**Approaches to Stakeholder Engagement and Monitoring**

## **Application of Hydrologic Tools and Monitoring to Support Managed Aquifer Recharge Decision Making in the Upper San Pedro River, Arizona, USA**

### **Laurel J. Lacher, Dale S. Turner, Bruce Gungle, Brooke M. Bushman and Holly E. Richter**

**Abstract:** The San Pedro River originates in Sonora, Mexico, and flows north through Arizona, USA, to its confluence with the Gila River. The 92-km Upper San Pedro River is characterized by interrupted perennial flow, and serves as a vital wildlife corridor through this semiarid to arid region. Over the past century, groundwater pumping in this bi-national basin has depleted baseflows in the river. In 2007, the United States Geological Survey published the most recent groundwater model of the basin. This model served as the basis for predictive simulations, including maps of stream flow capture due to pumping and of stream flow restoration due to managed aquifer recharge. Simulation results show that ramping up near-stream recharge, as needed, to compensate for downward pumping-related stress on the water table, could sustain baseflows in the Upper San Pedro River at or above 2003 levels until the year 2100 with less than 4.7 million cubic meters per year (MCM/yr). Wet-dry mapping of the river over a period of 15 years developed a body of empirical evidence which, when combined with the simulation tools, provided powerful technical support to decision makers struggling to manage aquifer recharge to support baseflows in the river while also accommodating the economic needs of the basin.

Reprinted from *Water*. Cite as: Lacher, L.J.; Turner, D.S.; Gungle, B.; Bushman, B.M.; Richter, H.E. Application of Hydrologic Tools and Monitoring to Support Managed Aquifer Recharge Decision Making in the Upper San Pedro River, Arizona, USA. *Water* **2014**, *6*, 3495-3527.

### **1. Introduction**

### *1.1. Social Context*

Balancing the social and economic water needs of humans with those of the environment, frequently referred to as sustainable water management, presents a global challenge, especially in arid and semi-arid regions, such as the American Desert Southwest. Understanding that the concept of sustainable water management is subjective, particularly in areas where human groundwater extractions have long exceeded average annual natural recharge, this study focuses on the tension between human demands for groundwater and the groundwater needs of an exceedingly rare perennial river system within the same basin of Southeast Arizona.

We report here on a combination of hydrologic tools and monitoring that are supporting significant progress toward many measures of sustainability on the scale of decades at one important site. The case for developing a regional groundwater recharge network along the Upper San Pedro River is built upon a series of studies and reports funded by the Upper San Pedro Partnership (Partnership), and vetted by its Technical Committee over a period of approximately 15 years. The Partnership is a consortium of 23 agencies and organizations working together to meet the long-term water needs of the Sierra Vista Subwatershed by achieving sustainable yield of the regional aquifer to: (1) preserve the San Pedro Riparian National Conservation Area (SPRNCA); and (2) ensure the long-term viability of Fort Huachuca. The purpose of the Partnership is to coordinate and cooperate in the identification, prioritization and implementation of comprehensive policies and projects to assist in meeting water needs in the Sierra Vista Subwatershed of the Upper San Pedro River Basin. Richter and others [1] provide a more complete discussion of the purpose, methods, and vision encompassed by the Partnership. In addition, recent groundwater modeling efforts have focused stakeholders' collective understanding of the hydrologic system on actionable strategies. Together, this body of work helps identify potential spatial and temporal groundwater recharge targets for mitigating many of the negative environmental, regulatory and economic consequences that may result if groundwater inputs to the San Pedro River diminish as a result of pumping, as predicted by groundwater modeling. Using this information, three of the stakeholders including the U.S. Army Compatible Use Buffer (ACUB) Program, Cochise County, and The Nature Conservancy are collaborating to develop an aquifer protection and recharge network of sites in the San Pedro River basin to protect flows in the river from anticipated pumping-related depletions over the next 50 to 100 years. This interim solution is intended to allow time to develop other longer-term strategies for addressing issues of the accumulated groundwater deficit in the regional aquifer and climate change. Examples of such longer-term strategies could include gradual elimination of consumptive use of groundwater, limitations on new pumping, enhanced utilization of urban runoff, and importation of water from outside the basin. Most of these strategies are controversial and/or expensive, and would require significant political and legal efforts to secure physical water supplies. This approach—using the best available science to implement a relatively uncontroversial and legally available interim solution to preserve baseflows while more difficult long-term solutions are pursued—may serve as a model for other dry-land river basins.

### *1.2. Study Area*

The San Pedro River flows north 279 kilometers (km) from its headwaters in northeastern Sonora, Mexico, to its confluence with the Gila River in southeastern Arizona, U.S.A. This paper focuses on the 2460-km2 Sierra Vista Subwatershed ("subwatershed") of the Upper San Pedro basin ("basin"), north of the United States-Mexico boundary (Figure 1). This subwatershed area includes about 47 km of the river, most of it within the San Pedro Riparian National Conservation Area (SPRNCA), designated by the United States Congress in 1988 to protect and enhance the riparian area and its aquatic resources [2].

**Figure 1.** Map of the Upper San Pedro Basin showing the extent of the USGS groundwater flow model [3] and the San Pedro Riparian National Conservation Area. The Sierra Vista subwatershed is the area north of the United States—Mexico boundary.

Elevations within the Sierra Vista subwatershed range from more than 2800 meters (m) above mean sea level in the Huachuca Mountains on the western edge of the basin, to 1052 m at the Tombstone stream-flow gaging station at the north (downstream) end of the subwatershed. Precipitation across the topographically diverse basin ranges from 35 centimeters per year (cm/yr) near Tombstone in the central-north part of the subwatershed to about 76 cm/year in the highest parts of the Huachuca Mountains [4,5]. Like other areas in the desert southwest, precipitation in the study area is predictably bimodal with a summer monsoon season from July through mid-September accounting for about one half, and a winter wet season from December through March that accounts for another one third of the annual precipitation. Occasionally, tropical storms will trigger very large runoff events in October, but otherwise the fall months are typically dry. Stream flow is lowest in May and June, with peak monthly flows occurring during the summer monsoon season (Figure 2). Average monthly minimum flows range from about 1300 cubic meters per day (cu-m/d) at the Palominas stream-flow gaging station in the south (upstream) end of the subwatershed to 19,300 cu-m/d at the Charleston station, and 8100 cu-m/d at the Tombstone station on the north (downstream) end of the study area (Figure 2). Snow melt in the Huachuca Mountains often supports flow in mountain springs and intermittent streams in the spring months of March and April.

**Figure 2.** Mean monthly stream flow for the three long-term monitoring sites (shown in Figure 1) on the Upper San Pedro River in the Sierra Vista subwatershed for the period of record at each site. The y-axis is plotted on a log scale to highlight the minimum flows in May and June.

**Mean Monthly Flow for Three San Pedro River Sites**

Groundwater discharge from the regional basin-fill aquifer supports baseflows in the river and evapotranspiration by near-stream phreatophytes. Groundwater pumping from that same aquifer supplies a human population in the region that is expected to increase by 46% by the year 2050 [6]. Sierra Vista, Arizona, is the largest municipality in the basin with a population of roughly 45,300 [7]. The U.S. Department of Defense installation at Fort Huachuca borders Sierra Vista on the west and north sides and is a major economic force in the basin [8].

Because of its federal designation and its globally significant biodiversity [9], the SPRNCA has been the subject of extensive hydrological and ecological research. One major finding was that stream flow permanence explained most variance in the basal area of two keystone riparian species, Fremont cottonwood (*Populus fremontii*) and Goodding willow (*Salix gooddingii*) [10,11]. As a

result, conservation strategies have focused on maintaining or increasing stream flow through

### *1.3. Hydrological Studies in the Basin*

### 1.3.1. General Hydrologic Processes

The Upper San Pedro River is one of the most intensively studied semi-arid stream systems in the world. Estimated ages of the earliest paleo-Indian sites along the banks of the ancestral San Pedro River date back to 11,000 to 13,000 years ago [12,13]. Two Clovis Indian sites have been associated with mammoth kills in the subwatershed, providing some of the earliest dates for human hearths of this culture [13]. The basin has been grazed since the time of the first Spanish explorers in the 1500s [14], and has hosted two major metals mining operations in Tombstone (late 1800s) and Bisbee (1880s–1975), Arizona. In addition, Cananea, Mexico boasts a major copper mine that is currently in active production. The major U.S. Department of Defense Army installation at Fort Huachuca has been in active operation since 1877 and has one of the earliest water rights claims in the basin [15]. More recently, the town of Sierra Vista has grown to include over 45,000 people (including Fort Huachuca). All of these activities have had significant impacts on the landscape and water resources in the basin. Hereford [14] presents a clear description of the land use changes coupled with exceptional periods of flooding near 1900 that led to significant entrenchment and stabilization of the San Pedro River stream channel and dewatering of much of the shallow alluvium of the river channel.

reductions in groundwater pumping and managed aquifer recharge at key locations.

The Walnut Gulch Experimental Station (Figure 1) was established in the northeast area of the subwatershed by the Research Division of the Soil Conservation Service in 1951, and has been the source of continuous instrument-based hydrologic and rangeland studies since that time [16]. In 1966, Brown and others [17] evaluated the water resources of Fort Huachuca, which lies immediately west and north of the City of Sierra Vista (Figure 1). Brown and Aldridge [18] estimated San Pedro River surface discharge from the international boundary with Mexico to its confluence with the Gila River and inputs to the system from tributary inflow and from mountain-front recharge. Much of the assessment of hydrologic resources in the basin that followed came as a byproduct of the development of groundwater models, including those by Freethey [19], Vionnet and Maddock [20], Corell and others [21], Goode and Maddock [22], and Pool and Dickinson [3].

The Arizona Department of Water Resources (ADWR) evaluated the groundwater resources of the basin in 1990 [23], and then again in 2005 [24], in order to determine whether or not the basin should be classified as an Active Management Area (AMA) under the 1980 Groundwater Management Act of Arizona. The ADWR determined that the basin did not meet the statutory criteria for AMA designation [23,24], but much of the research that was conducted as part of that assessment remains highly relevant. Pool and Coes [25] described the state of the knowledge of hydrogeology of the subwatershed. As part of that work, an extensive monitoring program was initiated in the subwatershed that included geophysical surveys, ephemeral stream flow monitoring, installation or refurbishment of a number of stream gaging stations, aquifer storage monitoring using microgravity techniques, and basin-wide water level monitoring. Much of this monitoring program continues today.

In support of the conservation mission of the SPRNCA, Section 321 of the Defense Authorization Act of 2004 [26] revised how the federal Endangered Species Act applies to the Fort Huachuca Military Reservation and directed the Partnership to "...restore and maintain the sustainable yield of the regional aquifer [of the Sierra Vista Subwatershed] by and after September 30, 2011." It also required annual progress reports on these efforts, which were produced for most calendar years from 2002 through 2011 (see [27], for example).

The Partnership sponsored several research reports during this time, which provided the scientific basis for development of the U.S. Geological Survey (USGS) groundwater model by Pool and Dickinson [3]. These studies include Coes and Pool's [28] assessment of ephemeral-stream channel and basin-floor infiltration and recharge, Gungle's [29] analysis of the timing and duration of ephemeral stream flow in the subwatershed, and Leenhouts and others' [30] analysis of the hydrology, vegetation-hydrologic relationships, and evapotranspiration requirements and plant-water sources in the SPRNCA. Leenhouts and others [30] established additional streamflow and groundwater monitoring in the subwatershed, including streamflow stage and permanence data, near-stream alluvial aquifer groundwater and vertical gradient monitoring, and a continuous meteorological and eddy covariance monitoring station for measurement of evapotranspiration in the SPRNCA.

A statistical analysis of the trends in streamflow in the San Pedro River was also published in 2006 by Thomas and Pool [5]. Leake, Pool and Leenhouts [31] used Pool and Dickinson's [3] five-layer groundwater model of the basin to conduct a capture and recharge analysis that mapped the effects of pumping and recharge across the subwatershed on groundwater discharge to the SPRNCA. Kennedy and Gungle [32] analyzed baseflow discharge from the subwatershed at the USGS gaging station near Tombstone, Arizona, at the north end of the subwatershed. Most recently, Lacher [33] updated the Pool and Dickinson [3] groundwater flow model to include recent changes in pumping and artificial recharge in the subwatershed, and simulated the projected effects of population growth-driven increases in pumping on groundwater levels and baseflow through 2105.

### 1.3.2. Managed Aquifer Recharge

In 2006, Stantec [34] developed a Flood Control Urban Runoff Plan for Cochise County that evaluated the size, placement, and efficacy of 30 existing and proposed stormwater detention basins on the west side of the subwatershed functioning as de facto recharge basins. As part of this study, GeoSystems Analysis [35] used a detailed precipitation-recharge-stormwater runoff regression model, based on the U.S. Department of Agriculture's Automated Geospatial Watershed Assessment Tool [36] for the urbanized Coyote Wash watershed in Sierra Vista to estimate the cost, recharge volume, and urban-enhanced runoff for that watershed and several others on the west side of the San Pedro River within the subwatershed. GeoSystems Analysis previously developed the stormwater regression model used for the Upper San Pedro Partnership and Cochise County based on detailed AGWA stormwater modeling results for the Coyote Wash watershed located in the City of Sierra Vista [37].

Predictive groundwater modeling [33] indicates that within the next 100 years, two regional cones of depression will merge and reduce groundwater flow from the regional aquifer to the San Pedro and Babocomari (a major tributary to the San Pedro) rivers (Figure 3). These simulations incorporate pumping increases over time that reflect U.S. Census growth rates [5,6] and maintain constant natural recharge and evapotranspiration at 2003 levels (as published in the USGS groundwater model [2]) for the entire 21st century. Figure 4a maps the west-east transect A-A' for the simulated groundwater-level profiles shown in Figure 4b. This transect goes through the Sierra Vista-Fort Huachuca cone of depression, and illustrates how simulated groundwater levels at the groundwater divide between the cone of depression and the river have already declined by 17% since pre-development conditions in 1902 and are predicted to double that level of decline, to 35%, by the year 2100. These reductions in groundwater levels produce commensurate percent reductions in groundwater gradient (change in head divided by distance) as measured from the same point on the groundwater divide to the river. While gradients directly under the river are not yet showing the same degree of impacts as those farther west, the ultimate outcome of these simulated changes would be greater baseflow losses in some losing reaches, smaller gains in some gaining reaches, and possibly the conversion of some reaches from gaining to losing. The resulting groundwater-driven reduction in baseflow and shallow groundwater would likely impair the dependent riparian systems [33].

**Figure 3.** Simulated drawdown (m) in the primary regional aquifer of the basin (**a**) in 2000; (**b**) in 2050; and (**c**) in 2100 [33].

**Figure 4.** (**a**) Cross-section A-A' in the center of the Sierra Vista subwatershed (adapted from Stromberg and others [10]; (**b**) Simulated groundwater-level profiles in 1902, 2013, and 2100 along the A-A' cross-section showing change in gradient (*ǻi*) from í17% in 2013 to í35% in 2100.

**181**

One potential solution to the problem of aquifer storage depletion would entail importation of at least some water from a source outside the basin [38]. However, at this time, importation does not appear likely in the foreseeable future (see companion paper by Richter and others [1]). In lieu of a replacement water supply, water managers and stakeholders in the subwatershed recognize the need for a near- to medium-term (*i.e.*, years to decades) intervention to protect stream baseflows and the associated riparian areas.

The City of Sierra Vista has more than 10 years of monitoring data from its Environmental Operations Park (EOP) where treated effluent is recharged at a rate of roughly 9100 cubic-meters per day (m3 /d) through artificial wetlands and recharge basins between the City's pumping center and the San Pedro River. This project was designed and constructed to create a groundwater mound to sustain surface water flow and supplement alluvial groundwater levels during low-flow periods [39]. Groundwater modeling that incorporates the EOP recharge data indicates that the project is successfully contributing recharge to both the nearby cone of depression in the regional aquifer and to baseflows in the San Pedro River [33,40]. Further groundwater modeling presented in this study suggests that additional recharge projects designed to utilize enhanced urban runoff, treated effluent or other local supplies near the San Pedro and Babocomari rivers may successfully mitigate anticipated pumping-related baseflow depletions for up to 100 years.

While conservation efforts within the subwatershed have reduced consumptive use of groundwater in the basin, particularly on the Fort Huachuca Army installation, the cumulative storage loss in the regional aquifer within the subwatershed from the past half century of pumping, estimated to exceed 800 MCM (refer to explanation provided in Section 2.3.2) remains a threat to the San Pedro River and its tributaries by intercepting mountain-front recharge and by reducing the groundwater gradient that drives aquifer discharge to the rivers. Because of this storage deficit and the fact that virtually all water use in the subwatershed depends on groundwater, almost any level of continued groundwater use poses an increasing risk of stream and riparian evapotranspiration capture over time.

### 1.3.3. Streamflow Permanence Monitoring

Direct measurement of baseflow, defined as the portion of streamflow derived from groundwater, is complicated by the effects of prolonged storm and/or snowmelt runoff (which tend to exaggerate baseflow estimates) and evapotranspiration (which reduces apparent baseflow). Acknowledging these complexities, practitioners have found that inter-annual stream-flow permanence in a river system that experiences intermittent drying in some reaches is a useful indicator of both hydrologic and ecological conditions in the San Pedro basin. Using a technique called wet/dry mapping, analysis of surface water presence (strict criteria are used to ensure consistent definition of surface water versus minimal puddles) during the driest time of year (mid June in the San Pedro Basin) reveals areas with high year-to-year variation in the length of surface wetting (Figure 5). By limiting the influence of storm events as much as possible, and assuming no significant changes in the condition of the riparian forest, these variations in wetted length are believed to be the best available physical expression of local groundwater conditions and may provide early warning of ecological changes [41].

**Figure 5.** Wet/dry results from the San Pedro Riparian National Conservation Area. The heavy river line shows reaches, which were wet in June 2013. Bars on right side represent wet reaches for each year, 1999–2013. Labels on the far right identify the 10 analysis segments, each covering 8.1 km. The four green properties (parcels 1 through 4) on map were recently acquired for groundwater protection and recharge projects. Redrawn from Turner and Richter [41].

Wet/dry mapping, as applied in the San Pedro River basin, uses citizen scientists annually to map the spatial extent of surface water in a river or stream. The method provides a comprehensive snapshot of conditions for the whole river at the same date each year, allowing comparisons of year-to-year variability [41]. Beginning in 1999, staff from The Nature Conservancy and the U.S. Bureau of Land Management coordinated volunteers to map the spatial extent of surface water within the SPRNCA. The exact dates varied slightly, but mapping was conducted during the third weekend of June each year to coincide with the lowest flow before the expected start of the summer rainy season. Through the years, progressively more of the river and its tributaries have been surveyed, increasing to 231 km of the mainstem and 266 km of tributaries in 2013. This paper addresses only the 80 km of mainstem river surveyed through SPRNCA.

### **2. Methods**

### *2.1. Wet/Dry Mapping*

Surveyors walked predetermined segments of the river, recording the coordinates of beginning and end points of all surface water segments greater than or equal to 9.1 m long using paper data forms and consumer-grade Global Positioning System units. They disregarded any dry gaps less than 9.1 m long in otherwise wet reaches. The resulting point coordinates were imported to a Geographic Information System (ArcGIS, Environmental Systems Research Institute, Redlands, CA, USA), and snapped to the closest points on a linear representation of the river. To identify localized trends, organizers partitioned the SPRNCA into 10 equal segments, 8.1 km long. Segments were analyzed for probability of trend using the Mann-Kendall test. For graphic purposes, we calculated and display the Sen estimate of linear trend (detailed methods are provided by Turner and Richter [41]). Starting in 2007, maps and summary data from the wet/dry surveys have been posted each year to a web site (http://www.azconservation.org) for public distribution.

Results from wet/dry mapping in the SPRNCA (Figure 6), as a whole, show about half the river has permanent surface water with some year-to-year variation but no trends. However, analysis of the smaller segments shows considerable variation Turner and Richter [41]). The southernmost segment, Segment 1, displays a significant downward trend, while Segment 2 trends upward. Most of the other segments have either year-to-year up/down results or a stable condition without trend. The distribution of wet and dry reaches has provided a simple way to prioritize and site conservation actions aimed at reduced groundwater pumping and managed aquifer recharge, as described in Section 3 below. Wet/dry mapping data are also expected to provide a quantitative measure of conservation progress after those strategies are implemented.

**Figure 6.** Total wetted lengths for the 10 analysis segments in Figure 3. Segment numbers increase from south to north (downstream). Revised from Turner and Richter [41].

### *2.2. Capture Mapping*

### 2.2.1. Overview of Capture

The Upper San Pedro River's position near the geographic center of an alluvial basin makes it a classic example of basin-fill hydrology. The existence of a major pumping center at Sierra Vista/Fort Huachuca between the primary area of recharge for the subwatershed (the Huachuca Mountains on the western boundary) and the river (Figure 1) also makes the basin a classic case study in groundwater capture. Capture is the increase in recharge to, and (or) decrease in discharge from, a basin that eventually occurs as a result of groundwater pumping. Theis [42] first addressed the consequences of groundwater pumping from a previously undeveloped system in 1940:

*"Under natural conditions…previous to development by wells, aquifers are in a state of approximate dynamic equilibrium. Discharge by wells is thus a new discharge superimposed upon a previously stable system, and it must be balanced by an increase in the recharge of the aquifer, or by a decrease in the old natural discharge, or by loss of storage in the aquifer, or by a combination of these."* 

Lohman and others [43] further clarified the definition of capture from Theis' description:

*"The decrease in discharge plus the increase in recharge is termed capture."* 

This definition of capture may be written as:

$$
\mathcal{Capture} = \Delta \mathcal{R} + \Delta \mathcal{D} \tag{l}
$$

where *ǻR* and *ǻD* equal the increase in recharge and the decrease in discharge, respectively.

In the Upper San Pedro basin, as in many basins in the southwest deserts of the United States, aquifer storage is plentiful as a result of recharge over thousands of years of depositional history, but potential sources of capture are limited primarily to reductions in riparian ET, reductions of groundwater discharge to streams (baseflow), and direct capture of streamflow. The numerical partitioning of extracted groundwater into its constituent sources through a water-budget process is a common and fraught practice in many water-short areas of the United States. Bredehoft, Papodopulos, and Cooper [44] attributed this practice to "perhaps the most common misconception in groundwater hydrology" which is "that a water budget of an area determines the magnitude of possible groundwater development." Under this line of reasoning, many water managers have concluded that all water entering the system as natural recharge is available for extraction without long-term deleterious effects. Brown [45] addressed the problem with this argument through an example of a well whose cone of depression eventually expands to intersect a stream in which he demonstrated that,

*"…the rate at which the hydrologic system reaches a new steady state depends on the rate at which the natural discharge [in his example to a stream] can be captured by the cone of depression."* 

Figure 7 illustrates the evolution of a groundwater system which receives natural recharge (through precipitation) at a fixed and limited rate, *R0*, and discharges to a stream as baseflow at a rate of *D0***.** In Figure 7a, the system is in equilibrium prior to any significant groundwater development. In this natural state of equilibrium (roughly prior to 1940 in the Upper San Pedro basin [3]) recharge equals discharge (Equation (2)):

$$R\_0 = \,^\bullet D\_0 \tag{2}$$

**Figure 7.** (**a**) Groundwater discharging to stream under equilibrium conditions; (**b**) Pumping at rate Q from a well intercepting groundwater that would have discharged to the stream under equilibrium conditions; Q is roughly equal to the rate of change in aquifer storage (¨S) plus reduced groundwater discharge to the stream (¨S); (**c**) Pumping at the same rate (Q) under a new equilibrium condition. Now, pumping is reducing groundwater discharge to the stream (¨D) and inducing recharge directly from the stream (¨R), and aquifer storage depletion ceases (¨S = 0). Adapted from Winter and others ([46], Box C, p. 15) and from Heath ([47], p. 33).

In Figure 7b, pumping at a rate of *Q* is superimposed on the system, producing a rapid rate of change in aquifer storage near the well (*ǻS*) and intercepting some groundwater that would otherwise have discharged to the river (*ǻD)*, but having no immediate effect on discharge to the stream (*D0*) due to the persistence of a groundwater "high" between the well and the river. At this point, pumping is roughly equivalent to the rate of change in aquifer storage plus the reduction in groundwater discharge to the stream (Equation (3)).

$$\mathbf{Q} = \Delta \mathbf{S} + \Delta \mathbf{D} \tag{3}$$

and recharge and discharge are no longer in balance (Equation (4)):

$$R\_0 \neq Q + \mathcal{D}\_0 \tag{4}$$

After some time (Figure 7c), the cone of depression intercepts the stream and reverses the gradient of the groundwater so that it now flows toward the well from all directions, directly capturing streamflow. Even though the pumping rate (*Q*) remains constant, recharge from precipitation also remains fixed at *R0*, so the only sources of water for extraction come reduced groundwater discharge to the stream, capture (increased recharge) from the stream, itself, and possibly some additional aquifer storage. A new equilibrium is achieved when aquifer storage is no longer being depleted (*ǻS =* **0***)* and pumping is balanced by the capture of stream flow and decreased discharge to the stream (Equation (5)):

$$R\_0 = \mathcal{Q} + (\mathcal{D}\_0 - \Delta \mathcal{D} - \Delta \mathcal{R}) \tag{5}$$

or,

$$\mathcal{Q} = \Delta \mathcal{R} + \Delta \mathcal{D} \tag{6}$$

Lohman [48] identified another potential source of capture not expressly described above. He referred to it as "salvaged rejected recharge from precipitation." This potential source of capture would comprise a new source of recharge (*ǻR*) as described in Equations (1) and (6). In the case of a large alluvial basin like the San Pedro, where much of the shallow alluvial aquifer is separated by a thick sequence of confining materials from the underlying regional aquifer, this source of potential capture would derive from the occasional replenishment of the shallow alluvial aquifer during runoff from one or more very large precipitation events. Runoff exceeding 25M cu-m/d occurs roughly every 5 to 6 years at the Palominas station (Figure 1), so any excess alluvial aquifer storage opened up by groundwater pumping could capture flood flows that would otherwise have been rejected and remained in the stream.

For the period 2000 to 2009, Kennedy and Gungle [32] found that alluvial aquifer storage changes that govern baseflow measured at the Tombstone stream-flow gaging station (near the far downstream end of the study area (Figure 1)) were a function of upstream riparian ET and summer precipitation. Although they did not identify groundwater pumping as a clear source of baseflow decline in that reach over that short period, they do caution that, "[c]ontinued regional groundwater pumping will, however, eventually lead to a decline in the contribution of regional groundwater to base flow." This contrast between the interannual scale of fluctuations in alluvial aquifer storage and the multi-decadal scale of changes in regional aquifer discharge is highly significant for long-term water management planning. Our study focuses on these longer-term regional aquifer changes, but acknowledges the importance in improving our understanding of the linkages between sources of capture at different temporal and spatial scales.

Groundwater simulations [3,33] indicate that the Upper San Pedro basin is transitioning between the second and third scenarios illustrated in Figure 7. Of course, streamflow is not the only potential source of capture in most groundwater basins, and may not be available at all, as in basins where the streambed has lost connectivity with the underlying aquifer. Other potential sources of capture include riparian evapotranspiration, groundwater inflow from boundary sources, and groundwater outflow from the basin. Because groundwater and surface water systems operate on such different time scales, stresses on a groundwater system may not manifest as baseflow depletions for many years. Unfortunately, "in many circumstances the dynamics of the groundwater system are such that long periods of time are necessary before any kind of an equilibrium condition can develop. In some circumstances the system response is so slow that [groundwater] mining will continue well beyond any reasonable planning period" ([44], p. 55–57). The goal of the study described in this paper is to anticipate the future impacts of 20th and 21st century pumping on the San Pedro River and to develop a strategy to mitigate those effects as they occur.

### 2.2.2. Development of Capture Map

Leake and others [31,48] developed a unique tool that utilizes the Pool and Dickinson [3] regional groundwater flow model to assess simulated pumping-induced capture of streamflow, spring discharge, and riparian ET across the model domain in response to a unit pumping stress at every location in the model, and presents the results as a map overlay with colored contours representing the amount of capture, as a fraction of the pumping rate, after pumping for a specified amount of time (Figure 8). Leake and others [49] provide detailed steps for developing a capture map using a groundwater model. Alternatively, capture for a given location can be calculated as the pumping time needed to reach a depletion-dominated supply (the time at which capture begins to provide greater than 50% of total groundwater pumped). A typical time scale for a basin in the American Southwest might be 0 to 100 years [50]. Capture map development can also be run in reverse, providing estimates of the total increase in streamflow, riparian evapotranspiration, and spring flow, as a fraction of recharge rate, after recharging at a unit rate for a specified amount of time [51]. The two are not necessarily the inverse of each other. Leake and others [31] calculated stream and riparian area capture resulting from pumping in the lower basin fill primary aquifer (layer 4 of the 5-layer groundwater model [3]) in the Upper San Pedro basin. They used the same method to calculate response in the stream/riparian area from recharge applied to the top-most layer of the model that overlies the extent of layer 4 (layers 1, 2, or 4).

### 2.2.3. Use of Capture Map in the San Pedro Basin

Richter and others [1] discuss the evolution of the capture map concept and its use in policy development within the basin. While the capture map does not replace groundwater modeling, it is a simple, intuitive tool that permits the layman to gain a better understanding of the degree of connectivity between the groundwater system and the river. Policy makers and stakeholders embraced the capture map in the San Pedro basin as a guide for various preliminary decisions on community development and ecological restoration.

**Figure 8.** Computed capture (as a percentage of pumping rate) of streamflow, riparian evapotranspiration, and spring flow that would result for withdrawal of water from model layer 4 at a constant rate for 10 years. The color at any location represents the fraction of the withdrawal rate by a well at that location that can be accounted for as changes in outflow from and or inflow to the aquifer for model boundaries representing streams, riparian vegetation, and springs. Redrawn from Leake and others [31].

### 2.2.4. Advantages/Disadvantages and Limitations of the Tool

Capture maps highlight where pumping will have the greatest impact on a water resource (such as a river) within a specified period of time, and thus make an excellent preliminary planning tool for water managers, commercial and residential developers, and conservationists who can benefit from reducing the immediate impacts of groundwater pumping. The similarly constructed recharge map provides similar planning benefits, offering the planner an initial overview of the most advantageous sites for storm-water, treated effluent, or other recharge facilities.

Despite the value of capture maps for communicating some complex hydrologic concepts to lay audiences, details about specific volumes and rates of capture for specific sources/sinks in the basin cannot be extrapolated directly from this tool. Capture maps, based on linear superposition, reflect the assumption of constant hydrologic properties of the aquifer, assuming that pumping causes no non-linear behavior in the hydrologic system. This limitation, and the fact that each cell of the model is stressed in isolation to make the map, means that capture maps cannot replace the use of a full groundwater model for examining the cumulative impacts of various stresses and sinks that change over time or that cause nonlinearities in hydrologic properties or boundary conditions.

### *2.3. Near-Stream Recharge Simulations*

### 2.3.1. Description of Model

Simulations in this study used the most recent and most sophisticated groundwater flow model of the Upper San Pedro Basin available [3]. Although the model area includes all of the 4500-km2 basin of which 40% is in Mexico, this study focuses on the Sierra Vista subwatershed within the United States (Figure 1). This MODFLOW-2000 [52] model is based on a uniform 250 m × 250 m grid spacing oriented north-south in alignment with the basin. The stream is represented by the Stream Package [53], hydraulic flow is modeled with the Layer Property Flow (LPF) package, and riparian evapotranspiration is modeled with the Evapotranspiration (EVT) Package of MODFLOW-2000. The two-season model reflects the seasonal significance of evapotranspiration in the riparian zones along the San Pedro and its tributaries. The cool season extends from mid October to mid March, and the warm season runs from mid March through mid October [3].

As with all groundwater models, this model has several limitations. Most significantly, it does not simulate flood flows, which are known to contribute significant recharge to the alluvial aquifer near the center of the basin as well as along some ephemeral tributaries to the mainstem of the San Pedro River. This seasonal "topping off" of the shallow alluvial aquifer may support baseflows in the river through one or more dry seasons, and is an important component of the riparian system. While this shortcoming means that the model tends to underestimate true baseflow (regional aquifer plus shallow alluvial aquifer contributions), it does not preclude the model as a useful tool for analyzing the effects of pumping on the regional aquifer's contribution to baseflow. For this reason, the term "baseflow" in this study refers strictly to that component of total baseflow that derives from the regional aquifer where most of the pumping in the basin occurs.

Figure 9 illustrates the conceptualized hydrogeologic cross section (upstream view) of the subwatershed and shows how the model layers correspond to that conceptualization. The model structure includes five layers in a stacked-bowl configuration representing sediment accumulation in the structural depression between two bounding mountain ranges, as is typical of the Basin and Range province of the western United States [3]. Only model layer 5 is found throughout the entire region (Figure 10).

**Figure 9.** Conceptualized cross section of basin showing model layers. Adapted from Figure 3 in Pool and Dickinson [3]).

**Figure 10.** Model layers [2] in plan view with San Pedro River intersecting various layers. Light blue line represents river location but does not necessarily signify perennial flow.

### 2.3.2. Use of Model in Water Resources Assessments

Initial groundwater modeling efforts by Pool and Dickinson [3] simulated transient groundwater levels and baseflows in the basin resulting from 20th-century (1902–2003) pumping and changes in riparian evapotranspiration associated with climate and evolving geomorphology of the stream channel [14]. These simulations reflected the development of a major cone of depression under the Sierra Vista/Fort Huachuca population center on the west side of the river, and a smaller area of groundwater depletion very close to the river near the communities of Palominas and Hereford, where agricultural pumping occurred for many decades (Figure 3a). The effects of groundwater use in Mexico also manifest as an irregular cone of depression progressing northward from the south edge of the regional aquifer.

Simulations by Lacher [33] built on the work of Pool and Dickinson [3] and projected pumping through the 21st century based on population projections developed by the Arizona Department of Commerce [54] and TischlerBise [55], and calculating the total drawdown (Figure 3) and change in baseflow over the 1902–2100 period (Figure 11). These simulations predicted widespread increases in aquifer storage depletion across the western side of the basin during the 21st century (Figure 3b,c). They also quantified projected declines in baseflow in the basin over the next 100 years due to pumping and evapotranspiration, as well projected increases in baseflow until about 2050 resulting from the recharge facility at the City of Sierra Vista's Environmental Operations Park (EOP) (Figure 11b).

**Figure 11.** Simulated baseflow capture from 1902 to: (**a**) 2000; (**b**) 2050; and (**c**) 2100. Capture is cumulative [33] and measured in cu-m/d. EOP indicates location of Sierra Vista's Environmental Operations Park wastewater recharge facility.

Water budget calculations and groundwater simulations suggest that cumulative total groundwater depletion is presently on the order of 800 MCM in the subwatershed with annual net storage loss over the last decade on the order of 5 to 7 MCM [56,57]. Policy makers in the subwatershed have considered the feasibility of importing water at a maximum rate of roughly 37 MCM/yr [38]. However, even that most optimistic rate of importation would require nearly 25 years to bring the subwatershed's cumulative water budget back into balance. In the meantime, ongoing pumping-induced baseflow capture would continue to depress the groundwater gradient between the pumping centers and the river (Figure 4) further reducing baseflows.

### 2.3.3. Near-Stream Simulated Recharge Site Selection

Although artificial recharge of urban-enhanced runoff through detention basins has long been considered a viable option for mitigating impacts of groundwater pumping, the basins have previously been designed to target the active cone of depression in the Sierra Vista/Fort Huachuca area [34] rather than the river. The concept of simulating targeted near-stream recharge arose from the process of quantifying the pumping-induced capture of baseflow (*i.e.*, a reduction of groundwater discharge from the regional aquifer to the river) over time using the regional groundwater flow model [33]. With simulated current baseflow capture for the entire basin and projections of aquifer storage and baseflow capture trends over the next century, near-stream recharge was identified as a potential mechanism for addressing projected baseflow "deficits" (declines from 2003 (end of transient model calibration period) baseline values) in targeted areas of the basin.

Taken together, the suite of hydrologic tools pointed to sections of the San Pedro River where greater protection was warranted and where meaningful impacts—such as converting an intermittent stream reach into perennial reach—could be made. Simulations with the groundwater model [58] suggested that developing a distributed, strategically located network of recharge projects near select river reaches might result in groundwater mounding that would effectively compensate for baseflow capture, thus, protecting baseflow and the riparian vegetation community from the anticipated effects of pumping for several decades or more.

### 2.3.4. Application of Recharge Models

A small core team of technical experts within the Upper San Pedro Partnership Technical Committee selected three trial sites for simulating hypothetical recharge near the river: (1) Palominas; (2) Garden Canyon; and (3) Babocomari (Figure 12). The site selection process was informed by both simple geography (upper, middle, and lower part of the subwatershed) and current and projected baseflow capture in the river system. Simulated recharge at each trial site consisted of surface recharge over four 250 m × 250 m model cells (0.25 km2 ) for the period 2012–2111. For each of the three trial sites shown in Figure 12, the recharge simulation investigation involved increasing recharge, as needed, to prevent any decline in baseflow below baseline (2003) levels downstream of the site over the simulation period while also preventing simulated surface flooding at the trial site.

Starting with 0.62 MCM/yr, simulated recharge at each site was incrementally increased, and baseflow response tested, until baseflow downstream of each site remained at or above 2003 levels for the 100-year simulation period. Figure 13 shows simulated change in the cool season (October–March) baseflow from 2003 (end of the transient calibration period) conditions in the years 2030, 2050, 2070, and 2111. As the decreasing cool (blue and green) colors in the northern half of the subwatershed over time indicate, baseflows are predicted to fall below 2003 levels in all of the mainstem San Pedro River and on the Babocomari by 2111. Recharge at the Sierra Vista EOP successfully maintains simulated baseflows in the mainstem above 2003 levels until at least 2070, but the impacts of pumping (deepening and widening cone of depression) overwhelm the recharge benefits by about the turn of the century.

**Figure 12.** Simulated trial recharge sites (Babocomari, Garden Canyon, and Palominas) in the Sierra Vista subbasin. Riparian condition class reaches delineated within the SPRNCA [10]. Adapted from Figure 42 in Stromberg and others [10].

**Figure 13.** Simulated difference in baseflow (cu-m/d) in basin streams from 2003 conditions in: (**a**) 2030; (**b**) 2050; (**c**) 2070; and (**d**) 2111.

### 2.3.5. Simulation Results

Hydraulic conductivity, antecedent depth to groundwater, and projected aquifer storage depletion over time controlled the simulated baseflow response to recharge at each of the three trial sites. Since simulated recharge applied at each of the three trial sites was tailored to meet the anticipated baseflow deficit downstream, each site demanded a unique recharge distribution and exhibited a unique response to the simulated recharge. Figure 14 illustrates the recharge rates determined by trial and error as necessary to sustain simulated baseflows at or above 2003 levels in the groundwater model [3] through 2111. While each of the three test sites exhibited a unique response to the simulated recharge rates shown in Figure 14, the Babocomari site exhibited a much higher demand for recharge and a much more pronounced response in the underlying groundwater than the other two sites [58]. For the purpose of illustration, only the Babocomari test site recharge results will be discussed in detail here.

**Figure 14.** Simulated recharge rates for the Babocomari, Palominas, and Garden Canyon test sites.

**Simulated Recharge Rates for Individual Test Sites**

Figure 15 illustrates the groundwater response to recharge at the Babocomari site. The black line represents depth to groundwater (DTW) under the stream adjacent to the recharge site in the baseline model with no simulated recharge at the Babocomari site. The orange line shows DTW in response to a constant rate of 0.62 MCM/yr. recharge, and the blue line shows DTW in the same location under the stream for the varying-recharge scenario illustrated by the green "Variable Recharge Rate" line. In the absence of any intervention (black DTW curve), simulated heads at this site are projected to drop by more than 10 m over the 21st century in response to pumping. However, these simulations suggest that incrementally increasing recharge from an initial rate of 0.74 MCM/yr in 2012 to 3.2 MCM/yr by 2100 would successfully maintain groundwater levels under the river at or slightly above the 2003 level.

The oscillation in the blue DTW curve reflects the fact that the simulated variable recharge increased groundwater levels under the river to a depth between the top of the evapotranspiration (ET) surface (1.5 m below top of aquifer) and the ET extinction depth at 6 m below the top of the aquifer. Thus, groundwater is more accessible to riparian vegetation in the varying-rate recharge scenario than in the baseline case, but baseflows still remain at or above 2003 levels in the area of the stream downstream where baseflow declines are projected under baseline conditions.

**Figure 15.** Simulated variable recharge rate at the Babocomari site and depth to water (DTW) under stream adjacent to the Babocomari recharge site from 2012 to 2111 for three scenarios: (**a**) no recharge; (**b**) 0.62 MCM constant-rate recharge; and (**c**) variable-rate recharge scenarios [58]. Evapotranspiration (ET) zone occurs between 1.5 and 6 m [3].

**Simulated Depth to Groundwater Under Stream Near Babocomari Site and Simulated Variable Recharge Rate Applied, 2012-2111**

### 2.3.6. Optimization of Recharge Rates

Section 2.3.5 presented the results of simulated varying-rate recharge at each of three trial sites individually along the San Pedro and Babocomari Rivers. One additional simulation combining the three trial recharge sites was run in order to answer the question of whether hydrologic efficiencies might be gained with simultaneous recharge at all three sites [58]. Because the reach of the San Pedro affected by simulated recharge at the Garden Canyon site is downstream of both the Babocomari and Palominas sites, some reduction in the required recharge at the Garden Canyon site was achieved by combining all three trial recharge sites in a single simulation. Figure 16 illustrates the reduced recharge required at the Garden Canyon site to maintain simulated baseflows downstream of that site at 2003 levels when recharge is simulated at the Palominas and Babocomari trial sites concurrently.

Total recharge required to maintain simulated baseflows at 2003 levels downstream of each of the three test sites is shown in Figure 17. The blue curve shows the total recharge required when the three sites are simulated independently of each other, and the green curve shows the total recharge requirement when all three test sites are simulated concurrently. The difference between the curves illustrates the efficiency gained by combining the three recharge test sites. The maximum total recharge rate in the independent simulations is 4.93 MCM/yr (3.35 MCM/yr average over the 2012–2111 period), but that value drops to 4.63 MCM/yr (2.91 MCM/yr average) for the concurrent recharge simulations. The average recharge saved by operating all three sites concurrently is 0.45 MCM/yr. Figure 18 shows the final simulated change in baseflow from 2003 conditions when recharge at the three test sites is optimized for concurrent simulation of the three sites.

**Figure 16.** Simulated variable recharge rates for the Babocomari, Palominas and Garden Canyon test sites. Simulating recharge at all three sites concurrently allowed a reduction in Garden Canyon recharge relative to the rates for the independent recharge simulations.

**Simulated Recharge Rates Optimized for Combined Test Sites**

**Figure 17.** Total simulated recharge at the Babocomari, Palominas, and Garden Canyon test sites required to maintain baseflows downstream of each site at or above 2003 levels when recharge is simulated at each site independently and when all three sites are simulated concurrently.

**Figure 18.** Simulated difference in March baseflow (cu-m/d) from 2003 conditions with optimized variable-rate recharge at three trial recharge sites in: (**a**) 2030; (**b**) 2050; (**c**) 2070; and (**d**) 2111.

2.3.7. Advantages/Disadvantages and Evolution of the Tool

Any perceived bias in the construction of the model, or simple disagreements among stakeholders with the technical modeling approach, can be problematic in terms of how modeling results will be used, if at all. Engagement of stakeholders throughout the model development process is essential for it to be embraced as a useful tool for decision making among varied interests. In this case, the groundwater model [3] was developed in response to wide dissatisfaction with some precursor models of the subwatershed. Richter and others [1] describe the process by which stakeholders were involved in the development of the Pool and Dickinson model [3] and the evolution of trust in the model among technical water resources experts and politicians in the basin.

Several years of experience with the Pool and Dickinson model [3] in developing and communicating results of baseline projections helped pave the way for using it as a tool to evaluate the prospects of near-stream recharge. The model made experimenting with various recharge rates and tracking the resultant changes in baseflow a fairly quick and inexpensive undertaking. While we feel that these simulation efforts successfully conveyed the general concept and potential merits of near-stream recharge to the public and decision makers, significant criticism arose from our choice of an arbitrary initial recharge rate of 0.62 MCM/yr for the hypothetical recharge sites. We viewed the initial near-stream recharge simulations as an exploratory mission to determine how much water would be required to produce the desired effect on baseflows in the San Pedro River, irrespective of the potential feasibility of attaining that quantity of water or distributing it in the locations of interest. As our initial simulation results were presented to stakeholders, many of them questioned the value in simulating recharge with water that is not available and for which no plans to develop were pending. We saw the near-stream modeling process as a "proof-of-concept" effort, but others quickly made the leap to the real difficulties in securing water for recharge. Significant time and energy were expended in efforts to bridge this conceptual gap, and in hindsight, more early effort to clarify the purpose and strategy behind the simulations would have been helpful.

### 2.3.8. Application of Recharge Simulations to Upper San Pedro Parcels

The primary value in the groundwater modeling efforts undertaken for the three "test sites" described above was in proving the potential benefit of multiple recharge sites near the river. In recent years, the U.S. Army Compatible Use Buffer program, Cochise County, and The Nature Conservancy collaboratively acquired and set aside for conservation purposes four parcels on the west side of the San Pedro River totaling 2226 hectares within the subwatershed (Figure 5). Collectively, these properties make up the physical sites currently under consideration for development of a network of near-stream recharge projects. The groundwater modeling process detailed above for the three hypothetical "test sites" was employed to some extent in the preliminary planning process for parcels 1 and 3 in Figure 5. As projects move from the conceptual phase to the physical site investigation stage, use of the groundwater model is being adapted to suit the project planning needs for the individual sites. While development of a recharge project on parcel 1 was constrained by several factors (parcel size, flood-control objectives, location of high-permeability soils off site), the current planning process for parcel 3 is relatively unconstrained. Modifications to model structure to reflect observed field conditions and refinement of the model grid to allow for more detailed simulation of potential recharge are two of the anticipated outcomes of the next phase of investigation at parcel 3.

### **3. Results and Discussion**

The suite of analytical tools discussed here is being used to inform key decisions necessary to balance groundwater use and maintain San Pedro River flows and associated riparian area ecological health. An extensive collection of hydrological studies and a robust, long-term monitoring program in the San Pedro basin have provided policy makers and stakeholders with important information about the complex relationships between groundwater condition, streamflow, and the ecological integrity of the riparian system within and near the SPRNCA. As a result, most of the stakeholders in the subwatershed understand that much of the San Pedro's riparian vegetation uses groundwater from the stream alluvium, and that this alluvial aquifer stores water from flood flows, receives groundwater from the regional aquifer, and contributes baseflow to the river during low-flow periods.

The groundwater model used in this study does not incorporate the complex interactions between flood-driven recharge of the shallow alluvium which influences baseflow to varying degrees from year to year, and pumping-induced depletions of the regional aquifer, which take decades to centuries to alter baseflow. While the model's authors made every effort to exclude storm-flow influences from the baseflow measurements they used in model calibration [3], it is virtually impossible to ensure that any given measured baseflow value represents only regional aquifer groundwater. The implication of this limitation is that the model may slightly overestimate the regional aquifer's contribution to baseflow, which would manifest as overestimated aquifer transmissivity and/or streambed conductance. That outcome, in turn, means that the model would also overestimate the simulated impact of pumping on baseflow until capture reaches its maximum (equilibrium) value. For the purpose of this study, which is to develop strategies for mitigating pumping-related impacts on baseflow, that response would be conservative and acceptable.

The Pool and Dickinson [3] model represents the culmination of years of study and is the best tool currently available for the study area. As discussed by Richter and others [1], using a groundwater model that is accepted by the vast majority of decision makers to perform predictive groundwater modeling has been essential for beginning to make management and project decisions from a common starting point. The modeling has demonstrated that within the next 100 years, two regional cones of depression will enlarge and likely change the nature of the hydrologic connection between the San Pedro River and the regional aquifer, reducing baseflow and impacting the dependent riparian system and thus wildlife populations.

Awareness and acceptance of an impending problem, however, is only the first step in finding a solution. The additional tools of the wet/dry maps and groundwater capture/recharge maps helped to focus management attention on finding both the most vulnerable areas of the system and the most beneficial locations for mitigation efforts. Analysis of wet/dry maps showing surface water presence during the driest time of year and areas with high year-to-year variation in wetted length may be the first physical evidence of changes in local groundwater conditions at the river. While wetted length is not solely controlled by groundwater conditions (it may also be affected by climate), different trends in various reaches of the river may help identify areas at higher risk of future ecological changes. Aligning these low-flow river reaches with the groundwater capture maps provided a rough indication of the rate that recharge in those areas of the aquifer might respond, expressing itself as baseflow in the San Pedro River. The capture maps also suggested the suitability of various locations for recharge that may communicate with the alluvial aquifer and/or the San Pedro River. On-site investigation of actual hydrogeologic conditions and suitability for recharge at a particular location is the first step toward refining a preliminary conceptual model derived from the tools described in this paper.

In the San Pedro basin, the use of these complementary approaches informed the purchase of the most hydrologically sensitive lands near or adjacent to SPRNCA (Figure 5) in order to both defer residential and/or agricultural development and provide the opportunity for near-stream recharge project development. The concept of a strategically located network of recharge projects near these river reaches evolved, in part, from the success of more than a decade of managed aquifer recharge at the City of Sierra Vista Environmental Operations Park in supporting both baseflow and replenishing the deep regional aquifer. We anticipate that recharging urban-enhanced runoff, storm water, and treated effluent near at-risk reaches shown would create groundwater mounds to sustain surface water flow and supplement alluvial groundwater levels during low-flow periods, effectively compensating for the otherwise deleterious impacts of encroaching cones of depression in the regional aquifer on baseflows for the next several decades or more.

### **4. Conclusions**

The application of the study methods presented in this paper and the development of system-specific techniques appear to have great promise for protecting dry-land riparian systems from the impacts of groundwater extraction, surface water diversions, and the extremes of climate change for up to several decades. The ecological, cultural, and economic significance of the San Pedro River has made it one of the most well-studied and understood river systems in the world. The tremendous volume of data and hydrologic tools already developed for this specific system coupled with many years of collaborative partnerships that have matured with the science make the San Pedro basin a very unique policy environment. There is likely no other river system with an identical set of social, political, and ecological circumstances, but the hydrologic analysis tools described in this paper can be used anywhere. The strength of collaborative partnerships and knowledge of which tools they jointly support is key to building a common understanding of the history, goals, and resources at hand to make real progress.

### **Acknowledgments**

The authors would like to acknowledge the Walton Family Foundation for its support in funding much of the science and policy development in the Upper San Pedro Basin in recent years. They would also like to express gratitude to the reviewers whose collective input substantially improved this paper.

### **Author Contributions**

The text of this article was written by Laurel J. Lacher, Dale S. Turner, Bruce Gungle, and Brooke M. Bushman, with contributions by Holly E. Richter. Laurel Lacher conducted background research on capture and urban-enhanced runoff, and performed the simulations of near-stream recharge. Bruce Gungle compiled and synthesized water budget data for the Upper San Pedro Partnership and provided the literature review. Dale Turner compiled and synthesized wet/dry mapping data. Brooke Bushman provided coordination of the research efforts in her role as the Upper San Pedro Basin Program Coordinator for The Nature Conservancy. Holly Richter provided content review and helped shape the presentation of our findings.

### **Conflicts of Interest**

The authors declare no conflict of interest.

### **References**


## **Development of a Shared Vision for Groundwater Management to Protect and Sustain Baseflows of the Upper San Pedro River, Arizona, USA**

### **Holly E. Richter, Bruce Gungle, Laurel J. Lacher, Dale S. Turner and Brooke M. Bushman**

**Abstract:** Groundwater pumping along portions of the binational San Pedro River has depleted aquifer storage that supports baseflow in the San Pedro River. A consortium of 23 agencies, business interests, and non-governmental organizations pooled their collective resources to develop the scientific understanding and technical tools required to optimize the management of this complex, interconnected groundwater-surface water system. A paradigm shift occurred as stakeholders first collaboratively developed, and then later applied, several key hydrologic simulation and monitoring tools. Water resources planning and management transitioned from a traditional water budget-based approach to a more strategic and spatially-explicit optimization process. After groundwater modeling results suggested that strategic near-stream recharge could reasonably sustain baseflows at or above 2003 levels until the year 2100, even in the presence of continued groundwater development, a group of collaborators worked for four years to acquire 2250 hectares of land in key locations along 34 kilometers of the river specifically for this purpose. These actions reflect an evolved common vision that considers the multiple water demands of both humans and the riparian ecosystem associated with the San Pedro River.

Reprinted from *Water*. Cite as: Richter, H.E.; Gungle, B.; Lacher, L.J.; Turner, D.S.; Bushman, B.M. Development of a Shared Vision for Groundwater Management to Protect and Sustain Baseflows of the Upper San Pedro River, Arizona, USA. *Water* **2014**, *6*, 2519-2538.

### **1. Introduction**

Many aquifers within the United States contain an essential—yet shrinking—supply of water for both people and natural systems. Groundwater resources support the irrigation of crops, drinking water supplies, and industry. Declining groundwater levels strongly affect riparian ecosystems in the semi-arid southwestern United States, where many aquifer systems are characterized by a large volume of water in storage, but a relatively small rate of natural annual recharge and discharge [1]. Because groundwater also supports natural systems such as wetlands, riparian systems, lakes, streams, and rivers, it has become increasingly difficult for water managers in this region to meet both increasing human water demands and the water needs of natural systems under persistent drought conditions [1,2]. In Arizona, perennial streamflows have significantly declined across the state—at least seven river systems could be dewatered over time, and an additional four will experience degradation if actions are not taken to reverse these trends [2]. In other words, it is increasingly difficult to manage groundwater supplies sustainably in either short or long time frames.

Widespread acceptance/adoption of "sustainable yield," which acknowledges long-term impacts of human pumping but tries to balance those impacts with environmental flow needs, represents a paradigm shift in groundwater management from the more common "safe yield" management paradigm that assumes it is acceptable for consumptive human uses of water to equal groundwater inflows. The name "safe yield" implies some level of security in terms of water availability, which by the very definition of the term is not afforded to water dependent natural systems if they are downstream of human water uses. Sustainable yield, on the other hand, more broadly addresses social, economic and environmental aspects of water availability. The methods for estimating sustainable yield, however, remain largely subjective and poorly understood by the general public, decision makers, and even water resources professionals.

This paper provides a regional case study of the Upper San Pedro River Basin of southeastern Arizona where groundwater management has focused for over a decade on the goal of sustainable groundwater yield, and proposes a generic framework for stakeholder engagement in this process, as well as lessons learned. While several questions and challenges persist, and the implementation of key strategies is ongoing, we present the tools and processes that have proven effective to date there. In particular, we offer a clear definition of sustainable use of groundwater, a conceptual framework for collaborative regional efforts to work toward attaining it along with an example of how the framework was applied in the basin, and examples of specific policies and projects that were developed to foster sustainable use there.

### **2. The Upper San Pedro Basin**

The Upper San Pedro Basin lies within the Basin and Range Province of the southwestern United States and is roughly bisected by the international boundary between Mexico and the United States (Figure 1). The basin is bounded on the east, west, and south by mountains that drain to the river near the center of the alluvial valley. The basin contains up to 520 meters of fill accumulated during the late Tertiary and early Pleistocene [3]. Runoff from the mountains recharged the basin fill over millennia, creating a vast aquifer underlying the San Pedro River. Today, dry-season flows in the San Pedro River depend almost entirely on groundwater discharge. In recent years, concern over potential pumping-related depletions of fragile surface water supplies has lent urgency to efforts to integrate the management of these two connected resources.

**Figure 1.** Map of the Upper San Pedro Basin showing the location of the San Pedro Riparian National Conservation Area managed by the U.S. Bureau of Land Management and the U.S. Army installation at Fort Huachuca within the Sierra Vista Subwatershed, just north of the United States—Mexico international boundary. From [4] (Figure 1).

Despite the fact that Arizona law generally does not recognize the hydrologic connection between groundwater and surface water, collaboration aimed at integrated groundwater-surface water management in the Upper San Pedro basin has been ongoing for decades, both within the United States and, to a lesser extent, between the United States and Mexico. The State of Arizona is in the process of delineating the "subflow zone" of river alluvium adjacent to the San Pedro River in order to protect senior surface water rights. Management, monitoring and modeling efforts focused on groundwater-surface water interactions in the Sierra Vista Subwatershed (Subwatershed) have supported vital scientific understanding of the physical basin. However, building a shared vision toward such an integrated water management approach along the binational San Pedro River is challenging for many reasons, including: differences in the political structure, economic development, cultural norms and values, water law, and language on either side of the border combined with a highly variable and complex physical system. Browning-Aiken *et al.* [5] laid out some of the processes used for collaborative watershed management of the San Pedro based on the principles of collective action theory, dispute resolution, adaptive management, power dynamics, and sustainability. The complex binational legal constraints pertinent to San Pedro water issues were also described by Browning-Aiken *et al.* [6]. This paper, however, focuses only on activities on the United States side of the border.

Within the United States, Congress created the San Pedro Riparian National Conservation Area (SPRNCA) in 1988 [7], the first Riparian National Conservation Area of its kind in the nation, and charged the U.S. Bureau of Land Management, to manage it "…in a manner that conserves, protects, and enhances the riparian area…" and other resources. This streamside riparian habitat, composed of Fremont cottonwood, Goodding willow, mesquite bosques, and sacaton floodplain grasslands, supports high levels of biodiversity and functions as a migratory bird corridor of hemispheric importance [8]. It includes approximately 64 km of the 279-km river that flows north to eventually join the Gila River, itself a tributary river to the larger Colorado River (Figure 1).

Several miles away from the SPRNCA another national asset, the U.S. Army installation at Fort Huachuca, had its own needs for groundwater to sustain its military mission associated with national security including communications testing. Fort Huachuca represents a major driver for southern Arizona's economy as the largest employer in the region and contributes approximately \$2 billion (U.S.) annually to the state's economy [9]. Located between these two federal interests, the residents of the City of Sierra Vista and Cochise County depend upon the same limited groundwater resources as the National Conservation Area and Fort Huachuca.

In terms of the legal and regulatory context, there are no state restrictions on groundwater extraction along the San Pedro River except for pumping from the zone of subflow, typically a narrow band along the river corridor corresponding to fluvially deposited alluvium. In Arizona, the legal priority of surface water rights is governed by the claim filing date: the earlier the filing date, the more senior and defensible the water right. However, a comprehensive adjudication of water rights on the Gila River system has been ongoing for decades, including federal and other water rights claims along the San Pedro, therefore, considerable uncertainty regarding the nature of surface water rights continues to exist. However, there is a clear legal distinction between surface water rights, which can be defended against more junior competing surface claims, and groundwater use, which is almost wholly unregulated in the state outside of specifically designated Active Management Areas.

Arizona law prevents placing any use limitations—or even requiring a water meter—on wells with a maximum pump capacity of 132 liters/min or less [10], even within the state's Active Management Areas. While the Upper San Pedro River Basin is outside of any state groundwater management area, Cochise County is one of only two counties in Arizona that have adopted requirements that subdivisions in the County must obtain a Designation of Water Adequacy. This program, administered by the Arizona Department of Water Resources (ADWR) requires water companies or subdivisions to show proof of a 100-year water supply before development is permitted. A total of twenty-seven privately owned local water utilities that depend upon groundwater supplies are regulated at the state level by the Arizona Corporation Commission and Arizona Department of Environmental Quality and operate in the area. In addition, three public water supply providers operate municipal water utilities.

### **3. History of Collaborative Water Management in the Basin**

A consortium named the Upper San Pedro Partnership (Partnership) was created through a Memorandum of Understanding (MOU) in 1998 in response to the Arizona Department of Water Resources Rural Watershed Initiative. This collaboration also developed, at least partially, in response to a situation where "dueling hydrologists" hired by different factions provided widely varying opinions about the fate of groundwater and the San Pedro River. The Partnership provided a vehicle for local jurisdictions to work together alongside a range of federal and state agencies, as well as with non-governmental organizations and business interests. The organization's purpose is to meet the long-term water needs of both the SPRNCA and the area's residents [11]. According to the Partnerships mission statement, this goal is to be accomplished through the identification, prioritization, and implementation of policies and projects related to groundwater conservation and (or) enhancement [12].

One of the first objectives for the Partnership was to create a collaboratively-developed regional groundwater model on which all interests could agree and then utilize it for decision making. The model, developed by the USGS, was funded through multiple federal agency budgets, with additional supporting studies funded by other some of the other Partnership members. Over the course of the five years it took to build, USGS hydrologists provided a high level of transparency about the structure of the model and the empirical data sources used to calibrate it [8]. Ultimately, this collaborative model building process served to establish a clear context and common understanding of the complexities of the hydrogeology, surface and groundwater systems, human water demands, and riparian vegetation trends and water needs. During this time, the Partnership was also recognized (in 2003) by the U.S. Congress via Public Law 108-136, (Section 321) [13], which charged the Partnership with achieving sustainable yield of the Sierra Vista Subwatershed regional aquifer by 30 September 2011.

The Section 321 legislation also required the U.S. Secretary of the Interior to deliver nine annual reports to Congress on the water management and conservation measures necessary to restore and maintain the sustainable yield of the regional aquifer by and after 30 September 2011. Future federal appropriations to the Partnership were to depend on the Partnership's ability to meet its annual goals for groundwater deficit reduction. On behalf of the Secretary and following Partnership decisions about methods and content, the reports were compiled and written by USGS staff of the Arizona Water Science Center with the assistance of other Partnership members. What the 321 legislation did not provide was a Congressional definition of the term "sustainable yield of the regional aquifer."

The Partnership chose a definition of sustainable yield based on the competing objectives view of sustainability [14]

"…managing [groundwater] in a way that can be maintained for an indefinite period of time, without causing unacceptable environmental, economic, or social consequences" [15].

This was operationalized to mean, "…a sustainable level of groundwater pumping for the Sierra Vista subwatershed could be an amount between zero and a level that arrests storage depletion, with the understanding that to call a level of use sustainable (other than zero) will entail some consequences at some point in the future" [16].

Figure 2 summarizes the progress of the 23 member agencies in their collaborative efforts to reduce the groundwater deficit through water conservation, recharge and reuse programs after the Section 321 legislation was enacted.

**Figure 2.** Estimated actual Sierra Vista subwatershed annual storage deficit and projected annual storage deficit that would have occurred had no management, conservation, or incidental yields due to human activity taken place. Incidental yields include increased recharge of runoff due to urbanization. The projected annual storage deficit is based on 2002 pumping rates and actual (not projected) population data from the State of Arizona and the U.S. Census through 2012. Modified from [17].

### **4. Development of a Shared Vision for Sustainability**

Based on the approach used along the Upper San Pedro River, we developed a generic conceptual model (Figure 3) consisting of six components for developing a shared vision for sustainable groundwater management among diverse stakeholders, and for the subsequent implementation of measures to test and refine strategies over time.

**Figure 3.** Conceptual Model for the Development of a Shared Vision of Sustainability for Integrated Water Management: The process of developing a shared vision of sustainability for regional groundwater management first requires an initial investment in *building a common understanding* of: the context of the water management challenge among stakeholders, the specific criteria for meeting environmental, social and economic needs, the theory of what needs to change to meet these criteria, and lastly, the strategies that will result in the desired outcomes. The subsequent *implementation of projects or policies* will have a better chance of providing multiple benefits and avoiding conflict when preceded by these steps.

Given the physical, economic, and social/legal/political scope and complexity of managing groundwater and surface water at the regional scale, various water managers and stakeholders typically have differing assumptions and opinions regarding management priorities, strategies, and potential outcomes. The development of a shared understanding of these multi-faceted complexities provides an essential foundation upon which to build a more collaborative approach and more robust solutions. This can be critical, especially given that the decisions of certain water managers and/or stakeholders may directly impact, either for benefit or detriment, the interests of others in terms of water availability. However, given the urgency, timing, and often political or legal sensitivities associated with some of these regional water management challenges, the initial investment in building a common understanding among various affected interests is not always made before the execution of plans, or implementation of projects or policies. Other authors have described that the "co-evolution of preferences" takes place through developing shared values and that people ultimately change their demands out of a motivation not just of helping others meet their needs, but because their perceptions and understanding of the issue have also fundamentally changed [18].

Therefore, a process that builds a common understanding of the specific criteria for meeting environmental, social, and environmental water management needs, as well as agreed upon strategies to address these criteria, is crucial to not only avoid subsequent conflict between interests but to build the most effective and robust solutions. In addition, specific desired outcomes for sustainability should be accurately defined, as well as the theory of what specifically needs to change to reach these outcomes with specific timeframes in mind. The strategies and theory of change can subsequently be tested through the collective implementation of projects and/or policies only if adequate monitoring programs are in place to do so at the appropriate spatial and temporal scales (Figure 3).

### *4.1. Develop a Clear Context*

In our experience, the physical complexity of groundwater systems alone can be tremendous, and the simultaneous consideration of social and economic factors can seem insurmountable to stakeholders working together to identify shared solutions for regional water management. One of the key lessons learned from collaboration along the San Pedro was the pivotal step of directly engaging stakeholders early in the process to participate in defining the scope of technical investigations from their own perspectives as decision makers. However, this approach is not intuitive for scientists, who have been trained to approach problems from a purely technical perspective. Decision makers need specific types of information for making high-risk policy, finance, and political decisions. Even if risks are inherent or unavoidable, the ability of scientists to quantify the probability of certain outcomes can be very useful for decision makers to choose between various alternatives. Enabling scientists to understand the specific information most needed by decision makers early in collaborative planning processes is imperative. The subsequent steps in developing a shared vision of sustainability all depend upon getting this initial step of the process right [19].

Developing social and economic criteria related to groundwater management is sometimes hard to definitively quantify or even anticipate in a qualitative sense into the future. However, in the San Pedro example, the fact that the core interests of some of the stakeholders were conceptually defined through the development of even qualitative criteria (such as "Fort Huachuca remains operational unless for reasons unrelated to water") helped to build a shared understanding and advanced discussions toward a possible solution set. One approach taken by the Partnership was to develop a decision support system (DSS) model based on the USGS groundwater model to help decision makers understand the impacts and cost-effectiveness of different combinations of water-conservation measures and management policies [20,21].

The primary technical tools used along the San Pedro River to explore the physical aspects of regional water management options and to aid in their development are discussed in detail by Lacher *et al.* [22]. While various research, data collection, and monitoring efforts were conducted from 1998 to 2014, the development of a groundwater model acceptable to all stakeholders was the overarching process that united stakeholders around a common understanding of the physical system. As stakeholders began deconstructing the complexities of the system by discussing the individual assumptions that went into that physical model, they recognized the need for improved information on which to base the model, and additional technical studies and/or predictive modeling tools were developed, such as stormwater/runoff models, evapotranspiration models, and riparian health inventories to provide better context regarding pivotal aspects of physical systems. As these types of additional studies strengthened the development of the regional groundwater model over time, it also had a secondary, but very important direct benefit for stakeholders—it improved their own common understanding of the physical system, and the eventual modeling results at the regional scale became more and more intuitive to them as well [20].

A common understanding of the legal, social and economic context of regional groundwater management issues emerged over the years from monthly Partnership meetings, multiple public opinion surveys conducted by various groups with an interest in regional water issues, and contracted studies, as well as through annual production of the "Legal Impediments" portion of the Section 321 reports to Congress. In addition, building an understanding of the relative costs for enhancing water supplies through a detailed assessment of a wide range of strategies proved essential for decision makers. The Partnership conducted a cost/yield study of 74 water management alternatives [23]. This process helped clarify the universe of all stakeholders' preferences and ideas about possible water management solutions and put all these alternatives in a common currency of relative cost and benefit. It also reinforced the concept that no one, or even several, projects could address the existing short- and longer-term water challenges. Instead, based on an increased understanding of the physical system, stakeholders came to realize that an array of long-term demand-reduction measures would be needed along with more immediate aquifer recharge and stream flow protection measures.

### *4.2. Define Specific Criteria for Meeting Environmental, Social and Economic Needs*

For the cost/yield study of water management activities, the Partnership defined seven environmental criteria for sustainability, including two groundwater, three surface water, and two ecological criteria, through a facilitated consensus-driven process (Table 1).


**Table 1.** The suite of criteria developed by the Upper San Pedro Partnership for sustainable yield.

### 4.2.1. Environmental Criteria

In general, some of the defining environmental criteria commonly associated with sustainable yield include: (1) avoid excessive depletion of surface water and excessive reduction of groundwater discharge to springs, rivers, wetlands, and riparian vegetation (defined as capture); (2) prevent the intrusion of contaminated water to the groundwater system during induced recharge; and (3) avoid irreparable impact to any groundwater-dependent ecosystems, and prevent land subsidence from groundwater withdrawals [24].

Along the San Pedro River, the groundwater-dependent riparian habitat composed of native Fremont cottonwood and Goodding willow forest would experience increased mortality and declining recruitment and give way to invasive, non-native tamarisk if groundwater depths were to fall and persist beyond about 3 m below land surface within the riparian area [25,26]. Loss of surface flow to capture would likewise also result in the loss of wetland herbaceous plants such as rushes, sedges, and bulrush, dependent on continuously moist soils [26]. As the number and length of reaches with perennial surface flow decrease, the number and diversity of aquatic species would decrease as well [27].

Since the environmental consequences of falling groundwater elevations in near-stream locations would include the degradation of the current riparian and aquatic habitats along the San Pedro River [26] affecting species dependent on those habitats as well, *maintenance of groundwater elevations* was clearly a key criterion. However, in consideration of longer term time scales and larger spatial scales, the increase in *storage of the surrounding regional aquifer* was also considered a meaningful criterion for inclusion as well, given its connection and influence on the near-stream alluvial aquifer. *Surface water availability, water quality, and riparian health considerations* were also included as key criteria for environmental sustainability.

### 4.2.2. Social Criteria and Consequences

Typically, when the social consequences of sustainable groundwater development are discussed, it is in reference to a physical shortage of available and (or) uncontaminated groundwater supply for human use. In general, access to good quality potable groundwater supplies should be equally available to all residents; down-gradient users should have a water right equal to up-gradient users; and groundwater pumping should not damage the existing water rights to spring and surface waters [24].

For the San Pedro, not only was the physical *availability of water to meet human demands* one of the social criteria identified by the Upper San Pedro Partnership, but for them, the ability of the *local communities to influence and control their own destiny in water management decisions* was also a clear priority. The eventual establishment of a regional network of sites owned and operated by County and/or municipal governments for managed aquifer recharge purposes clearly met those criteria.

The recharge of treated wastewater effluent to sustain groundwater is a human health concern expressed by some along the San Pedro River, and *sustaining water quality* was identified as one of the social criteria for overall sustainability. Since 2003, the City of Sierra Vista has recharged approximately 3.1 million cubic meters per year (MCM/yr) of its treated wastewater with the aim of mitigating the effects of long-term groundwater pumping in the Sierra Vista Subwatershed. Water quality monitoring of spring discharge has been conducted near this recharge site and it was found that no constituent concentrations had exceeded any federal standards as of 2009 [28].

### 4.2.3. Economic Criteria and Consequences

In the United States desert southwest, most water users expect groundwater development to fulfill the water demands for agricultural irrigation, industrial uses, and residential development while maintaining an economically feasible depth to water with regard to pumping and well construction costs [29,30]. For the San Pedro, Fort Huachuca's water use is constrained by federal law, specifically the Endangered Species Act (ESA). Two federally listed endangered species, the Huachuca water umbel (*Lilaeopsis schaffneriana* var*. recurva*), a small semi-aquatic vascular plant that grows in moist soils along the San Pedro River, and the southwestern willow flycatcher (*Empidonax traillii extimus*), a songbird generally associated with permanent water, rely on the surface flow and riparian system of the San Pedro River corridor for habitat. Fort Huachuca and the U.S. Fish and Wildlife Service completed a Biological Opinion in March 2014 addressing these issues for the next 10 years [31]. From the perspective of sustainable groundwater yield, then, the use of groundwater for economic development (*i.e.*, to support the Fort's mission) is constrained by endangered species such as the Huachuca water umbel and southwest willow flycatcher, as reflected in the ESA.

This tension between regulatory mechanisms and economic drivers reverses the normal relationship between water use and economic need. In this case, Fort Huachuca must minimize its water use in order not to cause unacceptable adverse economic impacts to the Subwatershed. Therefore the set of environmental criteria—specifically hydrological—as listed in Table 1 are also direct measures of the reduction of social and economic risks. Thus, the issue of balancing sustainable groundwater use in the Sierra Vista Subwatershed revolves around the environmental needs of the San Pedro Riparian National Conservation Area's aquatic and riparian communities, which are inextricably linked to local economies and the federal military installation that acts as an economic engine across all of southern Arizona.

### *4.3. Define What Specifically Needs to Change through Strategies and Desired Outcomes*

It became clear to San Pedro decision-makers and stakeholders through the process of developing the numerical groundwater model with the USGS, development of a spatially explicit Decision Support System (DSS) model based in the USGS groundwater model, and later working with consulting hydrologists who ran various simulations [22,32,33], that balancing human demands with flows in the river required not only the quantification of current withdrawal rates, but the management of impacts expressing themselves today due to water uses of the past century. In addition, predictive simulations of anticipated changes in groundwater trends over the coming century was essential to inform the decisions we make about current groundwater management. This was a much more complex and multi-dimensional view of the problem and its possible solutions, both spatially and temporally, than simply attempting to balance the current year's groundwater budget deficit. And yet, understanding these complex relationships actually clarified and simplified the necessary strategies and outcomes by setting more realistic expectations about what could be realized in the short-term, as opposed to longer timeframes. For example, a balanced groundwater budget within the Subwatershed might not be accomplishable within the time frames of years to decades, nor would it necessarily ensure that flows would be protected. However, over longer timeframes of centuries a balanced budget will be essential, and there are actions we can begin today that will contribute toward these longer term goals.

Once the regional groundwater model was developed, specialized applications of it were also possible, including development of a regional groundwater capture map (Figure 4) to provide a comprehensive spatial view of pumping and recharge impacts or benefits at any location in the subwatershed [34]. This more-intuitive representation of the system's physical dynamics resonated with decision makers and the public alike, and began to clearly highlight that near-stream locations had higher importance than locations closer to the regional cone of depression in terms of anticipated depletions of the river from pumping.

This understanding helped stakeholders move toward near-stream solutions that could most effectively benefit flows. While not eliminating the need to balance the overall groundwater budget throughout the subwatershed over longer time frames, strategies to sustain and enhance river flows in the short-term needed to center around near-stream locations to have the most impact. Once partners began to focus on the concept of an optimized suite of sites for both aquifer protection and recharge along the river corridor, the model was used to assess sites that could protect the most vulnerable sections of the river. This information was used to identify specific parcels of land that were feasible for acquisition. Some of those were later acquired, and subsequent groundwater modeling efforts used higher-resolution, local-area models to assess specific site and reach recharge characteristics and to simulate more specific recharge scenarios [22].

### *4.4. Implement Specific Projects and Policies*

Member agencies of the Partnership have been implementing a wide array of projects and policies targeted at their collective goal of "the identification, prioritization, and implementation of policies and projects related to groundwater conservation and (or) enhancement" for approximately 15 years. The establishment of a dedicated fiscal agent (the City of Sierra Vista) and ongoing collaborative budget approval processes gave partners an effective way to pool resources and apply funding swiftly to key science and monitoring needs as they developed. These projects included water conservation outreach programs, residential water audits, water fixture rebate programs, construction of stormwater detention basins, and effluent reuse and recharge facilities.

However, as more predictive model simulations were run, an increased focus developed on projects that had the most immediate benefits for flows in the river: those that increased near-stream aquifer recharge. This included land acquisition and conservation easements specifically aimed at the permanent retirement of high-volume pumping over the last two decades. However, given a better understanding of the temporal and spatial dynamics of the groundwater system, Cochise County, The Nature Conservancy and Fort Huachuca recently added a new strategy to near-stream groundwater protection efforts. The addition of multiple aquifer recharge locations became a priority to complement the existing City of Sierra Vista effluent recharge facility that went into operation in 2002. The Nature Conservancy identified available land in areas believed to be the most productive for near-stream recharge, based on the groundwater capture map (Figure 4), wet-dry mapping of surface flows (described below) and other tools [22]. Thanks to funding for land acquisition made available from the U.S. Department of Defense Army Compatible Use Buffer Program, and in combination with drastically-reduced property values due to depressed market conditions in the past several years, the opportunity to acquire land previously slated for development arose at near-stream locations. Between 2011 and 2014, The Nature Conservancy purchased 2056 hectares and Cochise County purchased another 194 hectares of hydrologically sensitive land (Figures 4–6). This network of four properties, totaling over 2250 hectares, and spread along 34 km of the river, far exceeds the amount of land originally envisioned as attainable for managed aquifer recharge purposes.

**Figure 4.** Groundwater capture mapping shows where managed aquifer recharge offers the greatest benefits for the riparian system within a 50-year timeframe. Dots indicate existing recharge projects. Historically most were constructed as detention basins for downstream flood control with secondary recharge benefits to the larger regional aquifer (over the warmer colors), and more recently to more directly benefit flows in near-stream locations (over the cooler colors). Outlined and numbered near-stream recharge sites are locations where aquifer recharge projects are currently under construction or being investigated as future project locations. Redrawn from [34].

**Figure 5.** One of a series of in-channel infiltration basins recently constructed at Recharge Site #1 near the San Pedro River where on-site monitoring (e.g., soil-moisture probes, pressure transducers) will be used to quantify the relative performance of the individual structures, within this constructed channel that receives surface run-off from upstream residential areas.

**Figure 6.** The in-channel basins under construction include infiltration trenches and drywells at Recharge Site #1, within the constructed channel. The channel is perpendicular to the river, and the river's riparian corridor is visible in the background.

After the acquisition of this recharge network, the collaborating partners are conducting site assessments that include hydrogeologic sampling, more-detailed stormwater modeling simulations, and potential source water locations. Ongoing planning by the County and local municipalities will now have additional options for managing both stormwater and effluent, at the places with the most regional benefit for river flows.

### *4.5. Monitor Progress toward Desired Outcomes*

The member agencies of the Upper San Pedro Partnership remain committed to securing continued funding for a broad suite of monitoring activities to evaluate the response of the regional groundwater system to their ongoing project and policy development. The USGS and USDA Agricultural Research Service monitor regional and alluvial aquifer water levels, main-stem, tributary, and low-flow mountain stream gaging, storage change monitoring using micro-gravity methods, and streamflow permanence. The Nature Conservancy, in cooperation with the U.S. Bureau of Land Management, also leads an annual monitoring effort using GPS mapping of surface flows, a technique called wet/dry mapping, to determine the absence or presence of surface flows during the driest time of year (mid June in the San Pedro Basin). This 16-year dataset is used to track year-to-year variability of the length of surface flows, and used to infer changes in alluvial groundwater conditions that may provide early warning of ecological changes [22]. The USGS also continues to monitor water quality at the Charleston gaging station on the San Pedro River as part of the National Water-Quality Assessment program.

The Partnership has recently committed significant funding to a comprehensive, multiple-year analysis of progress toward sustainable groundwater use in the Subwatershed. While that analysis is not yet complete, their previous annual reports to Congress included a suite of eight indicators to measure progress toward sustainable yield, as shown in Table 2. It is important to note how strongly this suite of indicators aligns with the previously defined environmental criteria for sustainability described in Table 1.

**Table 2.** A suite of eight indicators was used to describe progress toward sustainable yield in the Section 321 reports to Congress that were prepared by the USGS (e.g., [17]). They relate directly to the environmental criteria for sustainability developed by the Partnership.


### **5. Results and Conclusions**

Based on the San Pedro experience, approaches such as the Partnership that directly engage affected policy makers, stakeholder organizations, regulatory agencies, and the scientific community can more effectively implement the necessary projects or policies, than if the partners were addressing the same challenge as individual interests. The involved partners more deeply understand the need for management measures, but are engaged in the actual exploration and development of possible alternatives, and witness the results and progress toward specific desired outcomes through adaptive management over time [35]. This was certainly the case for the Partnership as they first quantified the annual yield from a wide array of member agency water conservation, reuse, and recharge projects, then implemented dozens of them since 1998 [6] (Figure 2).

However, the Upper San Pedro Basin is unique in many ways. The presence of an important federal military installation and a federally protected riparian corridor within the Sierra Vista Subwatershed have brought a level of interest and involvement absent from many other basins with similar hydrogeologic conditions. The federal nexus in water issues has also resulted in significant funding to assess groundwater pumping impacts and to help mitigate those effects. Without Congressional funding for the Partnership and much of the federally-sponsored scientific research that supported development of the groundwater model, the state of the science would likely not have advanced to its current level.

Despite these unique socio-political aspects, the San Pedro Basin represents one of the best examples of riparian corridors remaining in the desert Southwest. The Gila River that drains more than 60% of the state no longer has any undammed perennially flowing segments, and is dry over most of its length. Many of the state's once-flowing, now-dry rivers reflect the impacts of long-term groundwater pumping in the mid to late 20th century. They provide a stark reminder of how directly connected groundwater and surface water resources are for our desert rivers.

### *5.1. Lessons Learned*

### **Lesson 1:** *Engage decision makers and key stakeholders early in the process to define the science and technical tools needed for an integrated water management approach.*

These needs should be tailored explicitly to the existing conceptual models of key stakeholders, and the gaps in understanding, disagreements and/or misperceptions that they hold. This approach strengthens the foundation for shaping meaningful criteria for success, the formation of effective strategies, and the definition of meaningful desired outcomes. The Upper San Pedro provides an example of a stakeholder-driven process where project implementation was driven by an evolving science-based understanding of the system, and additional financial resources and political support were generated over time in response to an enhanced understanding and appreciation of the challenges and opportunities. As stakeholders progressively learned more about the system, they were also in a better position to make the case for generating additional public and private funding to support their efforts.

### **Lesson 2:** *Collaboratively define desired outcomes as specifically as possible both temporally and spatially.*

The process of defining "sustainable yield" for the San Pedro is still underway more than 11 years after Congress mandated its implementation in the Subwatershed. By some measures, such as per-capita water consumption rates and managed aquifer recharge, efforts to mitigate the effects of groundwater pumping have been very successful. However, developing the predictive models to more specifically understand the response of the physical system allowed decision makers to recognize that, while their previous efforts would aid in slowing overall aquifer storage depletion, they would not necessarily protect the river from pumping-induced capture in shorter time frames (years to decades). Later efforts to initiate near-stream recharge arose from a better understanding of both the spatial and temporal aspects of the system, and strengthened the recognition that both short-term and long-term actions and effects were important.

**Lesson 3:** *Stakeholders with varied interests are more likely to work successfully toward a common goal if they feel that their individual interests are represented, and can actually benefit from the process.*

Challenging economic and legal contexts should not prevent diverse parties from working toward a solution if they perceive that their interests are represented in, and perhaps even benefit from a shared vision with other interests. Even though some objectives may seem to be competing (e.g., preserving reasonable depths to groundwater for water supply wells AND preserving baseflows in the river), finding a common thread among the parties—such as preservation of a vital economic driver for the region—can lead diverse parties to define and accept a mutually beneficial outcome. Once stakeholders recognize what outcomes of a solution might look like (such as baseflow supported by near-stream recharge), they may better reach consensus about how to achieve that proposed solution. For the San Pedro, the acknowledgement of all three aspects of sustainability—economic, social and environmental—helped to build trust, agreement and eventually support among interests. In addition, it opened conversations to the consideration of more specific objectives aimed at both the short- and long-term. The parties acknowledged that preserving flow in the river was the most immediate short-term concern, while also recognizing the need for longer-term efforts to maintain supplies at municipal pumping centers.

**Lesson 4:** *The importance of effective communication and two-way learning between scientists and decision makers cannot be overstated.* 

While scientists and subject experts may recognize specific physical trends and processes in respect to hydrologic systems, other stakeholders may not agree on the nature or even the existence of them. Conversely, water managers and decision makers function within an operating environment that includes many dynamic political, financial, and legal factors that are not clear to scientists. Developing a shared understanding of these challenges as they relate to key water management decisions may take years. How do we help decision makers with little or no technical knowledge of complex groundwater hydrology understand that the pumping of half a century ago will manifest as declines in baseflow over the next half century? Even more problematic is trying to convince them to invest in expensive solutions to a crisis that—if the solution works—will never materialize. Accepting these hydrologic "mysteries" that are taking place in an invisible underground system they will never see requires a considerable leap of faith.

The burden lies with both the scientific community and decision makers to invest the required time and effort communicating and learning about the environmental, social, and economic aspects of regional water management to be able to develop meaningful collaborative strategies together. The development of a set of specific criteria for meeting environmental, social, and economic needs as part of a shared vision of sustainable groundwater management is an essential first step toward the development of that understanding.

### **Acknowledgments**

The authors would like to recognize the support of the Upper San Pedro Partnership, and its respective 23 member agencies, over the past 15 years in developing the science and fostering the collaboration required for the progress that has been made toward groundwater sustainability in the Upper San Pedro Basin. The USGS has also made significant contributions toward not only the development of the groundwater model in the basin, but also toward the conceptual understanding of sustainable yield on a broader basis. Lacher Hydrological Consulting has played a pivotal role in running various groundwater model simulations. The Department of Defense Army Compatible Use Buffer (ACUB) Program provided significant funding for the acquisition of land for aquifer recharge sites, and the Walton Family Foundation generously provided private funding for the subsequent design and engineering of initial aquifer recharge facilities. The authors thank David Goodrich and two anonymous reviewers for substantially improving this article.

### **Author Contributions**

The text of this article was written by Holly E. Richter, Bruce Gungle, Laurel J. Lacher, Dale S. Turner and Brooke M. Bushman. Holly E. Richter and Bruce Gungle wrote the bulk of the history of the partnership and development of the shared vision content. Laurel Lacher helped formulate the basic concept of the paper, provided input on the concept of sustainable groundwater use, and assisted with organizing the paper's structure. Dale S. Turner conducted background research on the technical tools, helped hone the sustainable yield concepts, provided content review, and also served as our primary internal editor. Brooke Bushman added current project implementation content, developed several figures and maps, and also provided content review.

### **Conflicts of Interest**

The authors declare no conflict of interest.

### **References**


## **The Role of Transdisciplinary Approach and Community Participation in Village Scale Groundwater Management: Insights from Gujarat and Rajasthan, India**

**Basant Maheshwari, Maria Varua, John Ward, Roger Packham, Pennan Chinnasamy, Yogita Dashora, Seema Dave, Prahlad Soni, Peter Dillon, Ramesh Purohit, Hakimuddin, Tushaar Shah, Sachin Oza, Pradeep Singh, Sanmugam Prathapar, Ashish Patel, Yogesh Jadeja, Brijen Thaker, Rai Kookana, Harsharn Grewal, Kamal Yadav, Hemant Mittal, Michael Chew and Pratap Rao** 

**Abstract:** Sustainable use of groundwater is becoming critical in India and requires effective participation from local communities along with technical, social, economic, policy and political inputs. Access to groundwater for farming communities is also an emotional and complex issue as their livelihood and survival depends on it. In this article, we report on transdisciplinary approaches to understanding the issues, challenges and options for improving sustainability of groundwater use in States of Gujarat and Rajasthan, India. In this project, called Managed Aquifer Recharge through Village level Intervention (MARVI), the research is focused on developing a suitable participatory approach and methodology with associated tools that will assist in improving supply and demand management of groundwater. The study was conducted in the Meghraj watershed in Aravalli district, Gujarat, and the Dharta watershed in Udaipur district, Rajasthan, India. The study involved the collection of hydrologic, agronomic and socio-economic data and engagement of local village and school communities through their role in groundwater monitoring, field trials, photovoice activities and education campaigns. The study revealed that availability of relevant and reliable data related to the various aspects of groundwater and developing trust and support between local communities, NGOs and government agencies are the key to moving towards a dialogue to decide on what to do to achieve sustainable use of groundwater. The analysis of long-term water table data indicated considerable fluctuation in groundwater levels from year to year or a net lowering of the water table, but the levels tend to recover during wet years. This provides hope that by improving management of recharge structures and groundwater pumping, we can assist in stabilizing the local water table. Our interventions through *Bhujal Jankaar*s (BJs), (a Hindi word meaning "groundwater informed" volunteers), schools, photovoice workshops and newsletters have resulted in dialogue within the communities about the seriousness of the groundwater issue and ways to explore options for situation improvement. The BJs are now trained to understand how local recharge and discharge patterns are influenced by local rainfall patterns and pumping patterns and they are now becoming local champions of groundwater and an important link between farmers and project team. This study has further strengthened the belief that traditional research approaches to improve the groundwater situation are unlikely to be suitable for complex groundwater issues in the study areas. The experience from the study indicates that a transdisciplinary approach is likely to be more effective in enabling farmers, other village community members and NGOs to work together with researchers and government agencies to understand the groundwater situation and design

interventions that are holistic and have wider ownership. Also, such an approach is expected to deliver longer-term sustainability of groundwater at a regional level.

Reprinted from *Water*. Cite as: Maheshwari, B.; Varua, M.; Ward, J.; Packham, R.; Chinnasamy, P.; Dashora, Y.; Dave, S.; Soni, P.; Dillon, P.; Purohit, R.; Hakimuddin; Shah, T.; Oza, S.; Singh, P.; Prathapar, S.; Patel, A.; Jadeja, Y.; Thaker, B.; Kookana, R.; Grewal, H.; Yadav, K.; Mittal, H.; Chew, M.; Rao, P. The Role of Transdisciplinary Approach and Community Participation in Village Scale Groundwater Management: Insights from Gujarat and Rajasthan, India. *Water* **2014**, *6*, 3386-3408.

### **1. Introduction**

India is the largest user of groundwater in the world with an estimated usage of 230 km3 per year [1]. Globally, areas under groundwater irrigation are the highest in India (39 million ha), followed by China (19 million ha) and the USA (17 million ha), and at present 204 km3 y<sup>í</sup><sup>1</sup> of groundwater is pumped annually in India [2]. Several reasons may be attributed to this phenomenon. Access to groundwater increased since the 1970s, when diesel and electric pumps became affordable to most small landholders. The causes of increased groundwater use are also rooted in population growth and economic expansion, and as result the annual groundwater use now probably exceeds the annual rainfall recharge. The notion of groundwater as a private resource, the rights of which are associated with land rights, has led to an exploitative extraction regime [3].

Farmers in semi-arid parts of India use groundwater to save rainfed crops from failure and to increase yields. As it is a relatively cheap and easily accessible water resource for individual farmers, irrespective of their farm size, groundwater is often extracted beyond its natural recharging capacity. With increased use of groundwater, the depth to the water table in many parts are fluctuating considerably during the year and the use of groundwater has risen to a level that groundwater from shallow aquifers is not adequate to meet the rising demand. Hence, groundwater from deeper aquifers is being pumped by the drilling of tube wells. There are also instances where fresh groundwater at shallow depths has been depleted, rendering marginal quality water from deeper layers of the aquifer [4]. The extensive use of groundwater resources by farmers all over the country pumping out water in an unregulated manner creates its own sets of complex management and sustainability issues.

The use of groundwater in agriculture is important in India, as it has enabled farmers to manage deficiencies in monsoonal rainfall, allowed dry-season irrigation, thus contributing to poverty alleviation. For this reason, a range of on-ground works to recharge groundwater are being implemented at the village scale throughout India as a part of the Government of India's "Mahatma Gandhi National Rural Employment Guarantee Act" (MNREGA) to enhance livelihood opportunities while developing a durable asset base. A significant part of the investment through MNREGA is for enhancing long-term, local water security by on-ground structures such as check dams, percolation tanks, surface spreading basins, pits and recharge shafts [5]. The development of on-ground structures to enhance groundwater recharge in India is called "watershed development". It is a long running program of Government of India and has significant hydrologic consequences, in particular, altering the runoff regime in downstream regions and groundwater recharge at local and regional scales.

In spite of all the efforts in the past to improve the sustainability groundwater in India, the problem of groundwater management is still severe, particularly in Rajasthan and Gujarat. In this project, called **M**anaged **A**quifer **R**echarge through **V**illage level **I**ntervention (**MARVI**), the research is focused on developing a suitable participatory approach and methodology with associated tools that will assist in improving supply and demand management of groundwater. Another important aspect of the project is education of and engagement with village communities, local NGO and government agencies to facilitate them working together to achieve sustainable groundwater management.

In this article, we report on some key findings from the MARVI project with two main objectives: (i) to show how basic hydrologic information collected by farmers and supplemented with hydrologic, agronomic and socio-economic data collected by the project team is leading to an assessment and understanding of the groundwater storage changes; and (ii) to reveal how this information and engagement activities can be used to empower village communities and other stakeholders to develop and assess their own viable options for groundwater management, including managed aquifer recharge and measures to reduce water demand while sustaining livelihoods.

### **2. The Study Watersheds**

The work reported here was conducted in the Meghraj watershed in Aravalli district, Gujarat, and the Dharta watershed in Udaipur district, Rajasthan, India (Figure 1). Both watersheds have a semi-arid climate, with the average annual rainfall in excess of 600 mm, but more than 90% of this rainfall is received during the monsoon months of June to September. Most farmers in the two watersheds grow maize, black gram, mungbean, guar, soybeans (recently introduced) and vegetables as *Kharif* crops during the rainy season. Wheat, gram and mustard are the main *Rabi* crops grown during the winter season. Farmers who have access to groundwater (and in some instances canal water) grow two crops a year and those who have access to water supplies throughout the year also grow some summer crops such as vegetables and fodder.

**Figure 1.** The Meghraj and Dharta watersheds. The inset map shows the location of the watersheds in the states of Gujarat and Rajasthan in India.

The occurrence and distribution of rainfall in both the Meghraj and Dharta watersheds are highly uneven in both time and space. *Kharif* crops are mainly dependent on the vagaries of the monsoon and are often at risk of either complete or partial crop failure due to inadequate rainfall, or rainfall not occurring at a critical stage of crop growth. Therefore, the uneven and erratic distribution of rainfall provides a major challenge to growing crops successfully and to sustaining a decent livelihood. When rainfall does not occur at the right time or in the required amount, some supplementary irrigation, also called "life saving irrigation", using rainwater stored on the surface or drawn from the underground aquifer systems can make a huge difference in avoiding crop failure.

A number of *in situ* conservation measures, including farm ponds, percolation ponds and check dams have been constructed in the two watersheds under both the Integrated Watershed Management (IWM) programs and MNREGA. The State Governments of Gujarat and Rajasthan, along with the Central Government have invested significant amounts in these two watersheds in the past, and continue to do so by constructing more of these structures. However, it is not clear how effective these programs are, and what impacts these investments are having on groundwater security. Figures 2 and 3 show the MAR structures in the Meghraj and Dharta watersheds.

**Figure 2.** Location of MARs in Meghraj.

**Figure 3.** Location of MARs in the Dharta watershed.

It is important to note that both watersheds are in hard rock aquifer areas. It well known that hard rock aquifers have low porosity and low connectivity and the movement of groundwater occurs through faults, fissures and fractures. Hence they store limited volumes, and when stored water is withdrawn by pumps, the emptied pores are not immediately filled by flows from adjacent areas. As result of low rain-recharge, and low porosity and low connectivity, the depth to water table fluctuates considerably during the year and significant water scarcity is often experienced during summer months or drier years.

Most farmers in the Meghraj watershed belong to a tribal community, while those in the Dharta watershed are from mainstream groups. The farming practices in the two watersheds have not advanced adequately to cope with declining water supplies. For this reason, the physical and socioeconomic conditions in the two watersheds provide a diversity of transdisciplinary research opportunities and engagement issues around groundwater recharge and management.

### **3. Study Approach**

The study approach in the MARVI project is underpinned by transdisciplinary research with a main focus at the "village scale" to understand the complex interrelations between rainfall, aquifer recharge, groundwater pumping and livelihood opportunities. We define transdisciplinary research as one in which both researchers from different unrelated disciplines and non-academic participants, such as farmers and other villagers, work together for a common goal and create new knowledge and theory to improve a complex situation. Thus, in this project we recognized the importance of involving local villagers and other stakeholders through this approach during the research process and engaged them in participatory groundwater monitoring and education to explore options for groundwater sustainability. Figure 4 illustrates the application of relevant social and natural sciences research and engagement to improve the field situation.

**Figure 4.** Study approach in MARVI project.

With an active engagement of local villagers, the project team collected a range of hydrologic, agronomic, economic, social and cultural data at selected clusters of villages over a two-year period. The engagement of villagers and data collected are then employed to understand the current situation and develop bio-physical and socio-economic insights to evaluate the current issues, identify options and strategies, provides a scientific and evidence-based input to enhance watershed development policies.

### **4. Field Research and Data Analysis**

### *4.1. Participatory Groundwater Monitoring*

A desired outcome of the MARVI project would be collective action at village level that is mutually beneficial to all the villagers, and from which other communities could learn. To achieve this, [6] have shown the need to develop Social Capital. This project used participatory approaches to help to develop social capital competences, with training programs aimed at supporting cognitive aspects of this social capital competence. In addition, the project used participatory monitoring for some data collection to also support this development.

Participatory monitoring of the water table was achieved through the engagement of villagers in the two watersheds. A total of nine local villagers, called *Bhujal Jankaars* (BJs)-a Hindi word meaning "Groundwater Informed" volunteers—were recruited in the Meghraj watershed and similarly 25 BJs were selected in the Dharta watershed. The main idea of recruiting BJs into this project was to give local villagers ownership in the project, build their capacity so that they can understand their groundwater issues and eventually help them to become champions of their community for improving the groundwater situation. The BJs were trained in a number of relevant aspects, such as mapping, water table and water quality measurements. They were also exposed to basic hydro-geologic concepts influencing groundwater availability for agricultural use.

The BJs were involved in weekly monitoring of the water table in open wells, 110 wells in the Meghraj watershed and 250 in the Dharta watershed. Prior to the monitoring of wells, all BJ's did a baseline survey with the help of the project team to compile the required information about village wells. The BJs monitored the groundwater changes through the measurement of water level depth from the ground surface on weekly basis and pH and EC on monthly basis. To assist in the reliability of the data collected by BJs, the project staff each week randomly measured the water level depth data in some of the wells using the same method as those of the BJ and crosschecked water level depths with those measured by BJs. This ensured that BJs were collecting the data properly.

### *4.2. Hydrologic Measurements*

Two automatic weather stations, one in each watershed, were installed to collect local weather information for water balance modeling and evaluating the effectiveness of recharge structures on groundwater levels. In addition, six automatic rain gauges were installed in local schools in the Meghraj watershed and five in the Dharta watershed. The purpose of engaging schools in rainfall measurements was to make the school children aware of the water availability in the area and its importance. Some villagers, acting as BJs in the two watersheds, were also given manual rain gauges to monitor rainfall.

A total of five groundwater depth sensors were installed in the Dharta watershed and three in the Meghraj watershed for monitoring water table depth at 15 min intervals. The measurement of water table depth at such a short interval is helpful to analyze rapid changes in water table depth following a pumping event or significant rainfall occurrence. Four water meters in each watershed were installed to measure pumped volume and water productivity for specific crops. Groundwater and soil samples were collected in the watersheds at different times during the study to examine whether they impose limitations for crop production and consequently on the livelihood of people.

The Central Ground Water Board (CGWB), an Indian Government organization, maintains and monitors observation wells across the country. In Gujarat and Rajasthan, CGWB monitors 1197 and 1111 wells, respectively [7]. The data is collected four times, Post-Monsoon (*Rabi*), Pre-Monsoon, Monsoon and Post-Monsoon (*Kharif*), which correspond to January, May, August and November respectively. For the current study, we chose two wells that fall in our study watershed areas. The data was collected from the WRIS website [8] which is maintained by the Indian Space Research Organisation (ISRO) and Central Water Commission (CWC).

### *4.3. Socio-Economic Survey*

Households in the two watersheds that contributed to this study were identified through the first survey step—participatory community assessments. With the help of community leaders and extension workers, a total of 500 households from eleven villages from the Meghraj watershed were randomly selected and interviewed, representing 21%–24% of total village households. Similarly, a total of 300 households were interviewed from five villages in the Dharta watershed, representing 24%–29% of the total village households. Interviewees were either household heads or members who make decisions on behalf of household members.

Social and economic data were collected using a pre-tested questionnaire. Four major aspects were considered: (i) Household's livelihood assets—human, natural, physical, financial and social assets [9]; (ii) household livelihood activities and strategies; (iii) household's perceptions of livelihood determinants, potential future changes, and adaptive intentions; and (iv) farming inputs and outputs. A pilot survey in both watersheds was carried out to finalize the questionnaire before full-scale surveys were conducted.

A separate survey was also conducted to answer research question about women's responsibilities regarding water and gendered perceptions of water use, availability and quality and who collects water. Five villages from Gujarat and Rajasthan were chosen and an average of 10 women, three men and three members of community associations were interviewed from each village. A random sampling method was used. Both surveys mentioned here were translated in Hindi and Gujarati and field investigators underwent a three-day training session conducted by the MARVI research team.

Cluster Analysis was used to identify relatively homogeneous groups of households/farmers based on selected groundwater use characteristics. Because the goal of this cluster analysis is to identify a typology of similar groups of groundwater users, the agglomerative hierarchical clustering method was used in this study.

### *4.4. Engagement with Schools and Local Communities*

Engagement of village communities through a range of activities that involved farmers, school communities and other members of village communities was an important part of the transdisciplinary approach used in this project. Field demonstrations on farmers' fields in the middle and end of the crop seasons were conducted on aspects, such as water requirements and water conservation practices, such as mulching and crop varieties that may be more drought tolerant or may result in improved income for a given water use. School children and teachers were engaged to record daily rainfall. Total weekly, monthly and seasonal values of rainfall were displayed on school noticeboards by students to create awareness about rainfall patterns and amounts and general awareness about water issues in their local areas.

Photovoice workshops were organized in villages and schools in both watersheds. Students and farmers were trained in photography and interestingly, most of them had never touched a camera in their lives. The idea of using a camera to express their ideas was something new and exciting for them and they actively participated in these workshops. They captured photographs regarding their past, present and future thoughts about water resources and groundwater as one of the critical factors of livelihood in village communities.

A newsletter in Hindi, called "MARVI Manthan"—a Hindi word Manthan meaning "deep contemplation"—was launched to share the project findings with village communities. This newsletter is published twice a year to coincide with the beginning of *Rabi* and *Kharif* seasons. The target audiences of this newsletter are farmers, the general community and other stakeholders, and the main purpose of the newsletter is to connect with local communities and pursue a dialogue with farmers for participatory use and management of local groundwater resources.

### **5. Results**

### *5.1. Understanding the Local Groundwater Situation*

The water table fluctuation for the Dharta and Meghraj watersheds, based on the monitoring of the Central Ground Water Board of India, are shown in Figures 5 and 6 respectively. The water table depth trends for the Dharta watershed indicate a depleting of groundwater from January 1994 to November 2000, after which the groundwater level seems to stabilize over the next 14 year period. From the twenty-year analysis, the net rate of groundwater depletion is of the order of 0.18 m per year. However, from the 2005 to 2013 period, the groundwater levels are increasing at the rate of 0.36 m per year. Over the 20-year period, the largest water table fluctuation, *i.e.*, the maximum difference between the lowest and highest groundwater level, was estimated to be 24 m. For the Meghraj watershed, the 18-year time series of groundwater levels show some large fluctuations in the water table but overall the net depletion in groundwater over 18 years seems to be negligible (Figure 6). The largest water table fluctuation for the Meghraj watershed was 8 m for the monitoring period considered.

**Figure 5.** Central Ground Water Board groundwater head trends for the Dharta watershed from January 1994 to November 2013.

**Figure 6.** Central Ground Water Board groundwater head trends for the Meghraj watershed from January 2005 to November 2013.

### *5.2. Bhujal Jankaars*

While the BJs were monitoring the water table on a weekly basis, they have also helped to develop good linkages between this project and local communities, creating awareness about the groundwater issues in the two watersheds. The evaluation of the BJ approach so far indicated that BJs interact extensively with their communities as they do their measurement tasks on a weekly basis. They are sharing project outputs that are written in the local language and tailored to the needs of village communities, particularly sharing some observed water table data to indicate the state of groundwater fluctuations in the area.

Discussion with village communities indicates that BJs are now becoming an integral part of the engagement process and data collection activities in the project in both watersheds. There is now an increasing acceptance of BJs in village communities in regards to the source of information about the local rainfall, extent of water table fluctuations and groundwater quality. They have also become an important link between the project team and the village communities for mobilizing farmers for project meetings, field demonstrations and dissemination of research findings from the project.

### *5.3. Engaging with Local Community*

The engagement activities with the farming community through water table monitoring, crop demonstration, work with local schools and targeted workshops have helped to create community awareness about the local groundwater situation and develop a suitable atmosphere for future meaningful dialogue with the community on local groundwater management issues and challenges. Competencies are being built to enhance the social capital of the area, with the aim of facilitating mutually beneficial collective action. The workshops with villagers have indicated that farming and village communities were all deeply concerned about groundwater quality and the rapidly declining groundwater supplies. The community is willing to explore options that will help in improved water availability for irrigation and drinking purposes but are currently more focused on water

availability in their individual wells and not appreciating that groundwater needs to be managed at the village and watershed levels and beyond.

The school engagement activities in the project included a poster and painting competition on a range of topics such as drip irrigation, water harvesting, soil testing and climate change. It was observed that the engagement of school children in the project extended the groundwater dialogue with parents and may also result in longer-term benefits. Another important engagement activity was photovoice workshops that involved school communities and villagers and resulted in several hundred photos and the subsequent selection of over 50 photos with text from the participants. Photovoice is essentially a participatory process of collecting information and expressing issues and concerns through photographs, and it can be used to effectively engage different groups and communities in a research project. It can particularly help individuals and communities groups to record and reflect on their ideas and concerns, help them promote critical dialogue and exchange of knowledge about important issues at different levels and reach policymakers for improving situations. Photovoice in this study helped to significantly engage teachers, students and villagers and facilitated them to think about their current groundwater situation and some options they may like to pursue to improve the situation. In particular, through a participatory photography process, the activity helped to explore some basic questions regarding what water means to villagers in the two watersheds. The analysis of photographs and text provided by the participants indicated that women and youth tend to emphasize future and personal responsibility while older male participants focused more on current problems. Unsurprising, the photovoice data indicated that participants saw the lack of water as the overarching problem, alongside specific human behavior and infrastructure problems.

In general, engagement and awareness campaigns aimed at educating the beneficiaries on a potential policy may be more effective, rather than using uninformed preferences based on expert opinion to drive policy decisions for complex natural resources management issues and challenges [10] (Rogers, 2013). In this project, the engagement with the local community and stakeholders has been an important element of transdisciplinary research on complex issue such as groundwater sustainability and will particularly assist in an effective dialogue with village communities, government agencies, including policy makers at the state and national levels, for participatory management of groundwater.

### *5.4. Socio-Economic Dimension of Groundwater Management*

A series of 11 questions in the livelihood survey elicited household attitudes and perceptions concerning the role of MAR, adequacy of groundwater to meet future needs, the influence of extraction of, and on, proximate wells, mechanisms to coordinate aquifer resources, who should pay or be compensated for aquifer remediation and willingness to adjust extraction for future needs.

In this study, it was assumed that the cluster analysis can be used to identify relatively homogeneous groups of households/farmers based on selected groundwater use characteristics. There are numerous ways in which clusters can be formed and the hierarchical clustering is one of the most straightforward methods to use. Hierarchical clustering can be either agglomerative or divisive. Agglomerative hierarchical clustering begins with every case being a cluster unto itself. At successive steps, similar clusters are merged. The algorithm ends with everybody in one huge, but useless, cluster. A divisive clustering starts with one large cluster with all objects in it and gradually broken into smaller sized clusters and ends up with clusters with one object (singleton cluster). Because the goal of this cluster analysis is to form similar groups of groundwater users, the agglomerative hierarchical clustering method is used in this study.

The cluster analysis of the factor scores in this study revealed a four-cluster solution (Table 1). Cluster composition and membership was predicted by eleven groundwater questions specified as x-axis variables. The composition and relative values of the four groundwater management clusters mainly differentiated attitudes regarding the effectiveness of MAR, the willingness to reduce extraction for their children's future use, the role of markets in groundwater management and relative impacts of proximate wells. The four clusters were defined:


The present, markets groundwater management (Cluster D) is characterized by a low likelihood of children taking over the farm in the future, does not believe that increasing the depth of the well will have an impact on neighbors, does not consider that MAR is the best way to maintain the well, does not deem that efficient water use is the best way to maintain the well but expects that a MAR scheme operated by a neighbor and self should be compensated. In contrast, the future, markets, MAR groundwater management (Cluster A) is typified by a high likelihood of children taking over the farm, the belief that increasing the depth of the well had an impact on neighbors, judge MAR as the best way to maintain groundwater resources, and believe that a neighbor's groundwater use reduced water in their own well.


**Table 1.** Response to different questions for different clusters.

**Table 1.** *Cont.* 


The relative proportions of groundwater management cluster membership of respondents located in the two watersheds vary. About 9% of respondents from Gujarat are assigned membership in Cluster D, and 34% in Cluster A. The Rajasthan respondents are characterized by high proportional membership in Cluster D (55%) and Cluster A (40%). The farmers in Cluster D derive their groundwater information from traditional knowledge (42%), family (20%) and neighbors (19%), while those in Clusters A and B acquire information from family, neighbors and television. However, the farmers in Cluster C only rely on traditional knowledge (26%) and family (22%). As to the level of trust, there is no significant difference among the four clusters.

The cluster analysis indicates that groundwater management perceptions and attitudes influence the willingness and capacity of well owners to adopt specific remediating technological solutions and their compliance with policy incentives. Differentiated perceptions and information sources revealed in the cluster membership and the distribution of clusters in the two watersheds suggests that a suite of targeted technologies and incentives, in contrast to a reliance on single technological solutions and policy instruments, is likely to achieve the highest adoption rates [11]. The analysis provides the basis for designing watershed specific policy instruments and technologies that align with statistically differentiated attitudes and perceptions revealed in the four clusters.

### *5.5. Groundwater and Gender*

Though women are found to be significantly involved in irrigated agriculture in both the Dharta and Meghraj watersheds, the revenue generated from agriculture is entirely controlled by men. This clearly separated intra-household activities according to gender. These activities, however, are not separate from the water users' perspective, and this often impedes women's access to and control over this scarce resource. For instance, men usually have a greater say in water provision for irrigated agricultural production, which in turn influences agencies responsible for infrastructure and determines availability and security of water from the women's perspective. Even production from women's fields and household gardens is often controlled by men to a certain degree, as is the availability of water for non-agricultural tasks. This bias of water allocation and control is even greater in times of water scarcity.

Women were found to be responsible not only for domestic water use but also in the productive uses of water, such as vegetable growing and herding. The women interviewed are almost exclusively responsible for domestic chores and for maintaining hygiene in their households. Most of them commented that water scarcity has a direct impact on their access to water within the household as well as on the time they and their daughters and daughters-in-law have to spend in water collection. This means the time available for other activities in the household and livelihood opportunities becomes limited. In addition, mothers are concerned that their daughters are missing school because they have to help in water collection. A majority of them suggested boosting women representation in groundwater management.

The women interviewed are almost exclusively responsible for domestic chores and for maintaining hygiene in their households. Due to inadequate water being locally available for basic consumption in poorer households, women fetch water from nearby villages, where applicable, walking for more than 30 min and up to one hour per trip. The physical strain of collecting water is doubly compounded during the peak of summer, and women have to wait in long queues at water sources. This shows the precarious situation of women in households and also indicates how women are compelled to shoulder additional burdens for the welfare of their families.

Overall, the analysis of gender related issues of water indicate that for achieving broad livelihood improvement outcomes the needs of water from women's perspective cannot be ignored. Furthermore, the gender aspect of groundwater needs to be considered along with securing sustaining groundwater for crop production.

### **6. Discussion**

### *6.1. Capacity Building of BJs as Local Champions*

The training program of eight modules spread over about six months was aimed to orient the BJs regarding the MARVI project and to build their understanding about geology, hydrology, watershed management and mapping. While it was comparatively easy to develop an understanding of the depletion of surface water resources, the measures used for water harvesting and groundwater issues are quite complex to comprehend, both for the village communities as well as the project research partner field staff. However, in presenting these module inputs it was realized that, despite the difficulties, it was possible to demystify the technical aspects of groundwater management in a language that villagers could understand. It was also recognized that capacity building for the BJs has to be a gradual and continuous process, and one which blends theoretical inputs with practical exercises in their own villages in order to help them grasp these complex issues. Convincing people to work on an action research project that does not give them direct benefits requires a lot of effort. In addition, it was observed that groundwater management is a new concept that is not easily understood by rural communities. Retaining the BJs in the midst of other work opportunities available in and near the villages at a high remuneration was also an issue.

Besides well monitoring, the BJ's were also linked into other key project activities, viz.; village level meetings, field days during and after crop demonstrations and seed and fertilizer distribution. The BJs shared their experiences in a monthly meeting with project community organizers and prepared the plans and strategies for further activities. The BJs also interacted with other village members individually or through various village institutions like farmers' club, *Sujal Samiti* (water co-operative), *Gramsabha* (village council) and the like. In this way, the BJs were working as a communication bridge between the MARVI project team and villagers.

An interesting aspect of BJ involvement in this project was that the information collected by BJs made people in the villages curious about the MARVI project activities and triggered further communication. The location of monitoring wells also helped in spreading information as the wells were widely dispersed and every well owner asked why was the BJ taking readings and what will come out of it? These questions assisted in starting communication with the farmers about the current issues of groundwater scarcity. Some of the BJs became quite capable in preparing charts for displaying current rainfall and well water depth and hung these outside their house so that more people could see the results. Thus, as result of the BJ's involvement in the project most people in the villages came to know that this is a research project, not another project that focus on onground construction works, and that the research data which are being collected will be helpful for them in the future.

Given the skills that the BJs have acquired through their training, and subsequent practical experiences, they will be able to continue to contribute towards various development projects being implemented by local NGOs and the Government agencies, both in their own and the adjoining villages. It was observed that there was a dearth of competent human resources available at the village level before the commencement of this MARVI project, but now local villagers have relevant local groundwater knowledge, data collection experience and significant interest to improve their groundwater situation. It would be foolhardy for anybody not to utilize the local knowledge and skills on water and agriculture acquired by these BJs. At least one project partner is now collaborating with the Government of Gujarat to promote and effectively use the BJs to help implement the Mahatma Gandhi National Rural Employment Guarantee Act (MGNREGA), while in Rajasthan the BJs can continue to work with other government funded watershed development projects that are about to commence in the watershed. This is also in line with a recent report by the Planning Commission of India highlighting the need for building strong partnerships and collaborations among a broad spectrum of institutions and community to monitor and implement groundwater management strategies across India [12].

### *6.2. Managing Complexity of Groundwater Use*

Farmers in the two watersheds face significant water shortages and the risk of crop failure even with a slightly abnormal decline or delay in monsoonal rains. Because of advances in drilling technology and its easy access, there has been a massive increase in the drilling of tubewells and deepening of open wells for irrigation. This has motivated farmers to extract groundwater from whatever depth it is available. As a consequence, this phenomenon has changed the idea of equity and sustainability of groundwater use in the two watersheds. Not only is the water table lowering or fluctuating considerably from year to year, which impacts on crop production but, also the quality of groundwater has deteriorated due to pumping from deeper aquifers. For example, in the Dharta watershed, there is some evidence that fluoride levels in groundwater (which is also used for drinking water supplies) for some villages are above the values recommended in the World Health Organization's guidelines [13]. In general, the groundwater situation in the two study watersheds also illustrates what is prevailing in many other parts of the States of Gujarat and Rajasthan and for that matter in many States of India.

Another complex and difficult issue is determining the limits of groundwater available for withdrawal, especially in hard rock aquifers with limited storage capacity. Without mechanisms and sanctions to coordinate individual withdrawals to meet socially agreed sustainable levels, groundwater use represents an open access resource where at the end everyone loses when the groundwater system gets over exploited. Access to and availability of groundwater affects household livelihoods and community well-being and, in some instances in India, it has been reported to have led to farmers taking the extreme step of ending their own lives [14]. Therefore, a proposal to coordinate groundwater use remains a source of conflict between competing farmer interests and is the subject of significant political argument. The flow of groundwater does not recognize boundaries of individual farms, villages or watersheds and the subtractive attribute implies that one farmer's gain through over-pumping incurs a loss of access for others. Therefore, in the current situation it is almost impossible to ensure equity of access among farmers and regulate its use sustainably.

While groundwater recharge of varying amounts occurs during each monsoon season, there has been a net lowering of water tables in many parts of Gujarat and Rajasthan [4]. The consequences are notably manifest during the *Rabi* season. In the absence of institutions, regulations to share the costs and risks of aquifer remediation, individual farmers are unlikely to undertake mitigating actions independently, as they are unlikely to be compensated for the benefits shared by the common pool community. The depth to the water table increases with pumping over a longer time period, and the impact of such pumping usually extends over larger areas. While groundwater recharge of varying amounts occurs during each monsoon season, the real impact of any lowering of the water table is severely felt during drought periods. Once groundwater has been extracted in excess of annual recharge, it is not easy for individual farmers to reverse this situation. It then requires co-operative actions from group of adjoining farmers to see any real impact of local recharge and demand management on the water table situation.

### *6.3. Challenges of Sharing Groundwater*

It is important to recognize that groundwater is an invisible, common property resource that is accessible to anyone who has a well and a pump, or can afford to dig a well and install a pump. The amount of groundwater available in hard rock aquifers with their limited storage capacity is not easy to predict, and hence it is hard to estimate the limit of groundwater pumping. Groundwater use is a good example of "tragedy of the commons" and "survival of the fittest" but at the end everyone loses when the groundwater system is over exploited. Groundwater can affect the livelihood and wellbeing of communities. Therefore, the regulation of groundwater use is a very sensitive issue for farmers and can become a significant political issue if not tackled properly

Common pool resources are characterized by costly exclusion of beneficiaries, a characteristic shared with public goods and rival consumption (or subtractable usage), a characteristic shared with private goods [15]. That is, the withdrawal of additional groundwater by an individual well owner appropriates and subtracts from the total available aquifer volume, reducing the opportunity of other irrigators to make use of the groundwater resource. When joint outcomes depend on multiple actors contributing inputs or actions that are costly and difficult to quantify and there is a lack of policy instruments to restrict usage, incentives exist for individuals to act opportunistically, often appropriating to a level where aggregate overuse occurs. A social dilemma occurs when individuals are tempted by short-term gains to over appropriate the common pool resource, thereby imposing group-shared costs on the common pool community. Additionally the opportunity exists for some individuals to free ride and benefit from the reductions in extraction or increases in recharge committed by other aquifer users. Individual over appropriation will eventually lead to falling water tables, increased pumping costs and lower crop productivity for all farmers.

The solution to the overexploitation of groundwater may well come from adequate licensing to access the resource. In India, the electricity for groundwater pumping is free in a number of states, and as such this has aggravated the problem of overuse groundwater. On the other hand, the State Government of Gujarat in recent years implemented a policy to limit groundwater pumping through limiting hours of electricity supply by constructing a separate power grid for farm sector. While the policy implementation in Gujarat has certainly limited the hours of pumping, this also pointed out that any attempt to deal with the issue of limiting user access to groundwater, in this case limiting the supply of electricity through a separate power grid, does involve some transaction cost of policy. An important outcome of the transdisciplinary research in this study would be to understand the issues and options of groundwater overexploitation from a number of perspectives and design a system of effective control for groundwater access.

### *6.4. Making Community Engagement Effective*

Groundwater, being a common resource accessible by every member of the community individually, requires a common approach to its management. However, in general, past efforts of community involvement in aquifer management have been shown to be quite inefficient [4]. Therefore, for this study, it was decided to tackle this issue through more effective participation by the village communities involved, and thus community engagement was critically important to the success of the study.

Effective participation is important groundwater management and in general it depends upon commitment rather than coercion and cannot be fully programmed or tightly controlled. Further, it involves resolving issues about the nature of participation in terms of extent and quality, as well as questions about who should participate. Sriskandarajah *et al*. [16] identified key themes in participative projects and included (i) the importance of the scope for genuine participation in decision-making if "community participation" is to be meaningful; (ii) the need to see participation as a continuing process of negotiation and decision-making rather than a once only input into project planning; (iii) the need for clear identification of interested parties as the first step in establishing community based resource management programs; and (iv) the need to recognize and build upon local knowledge and existing local resource management and institutional support practices.

A number of different forms of "Citizen participation" have been identified by Arnstein [17] in the form of a ladder, which moves from very tokenistic forms of participation (manipulation) and progresses to more meaningful forms of involvement (Citizen control), as illustrated in Figure 7. In the context of resource management projects, Sriskandarajah *et al*. [16] also suggested that at the three higher levels, community participation involved local people in making decisions about the management of the resources they used, while at the lower five levels, these decisions were made by bureaucratic "experts", with community members only being involved as either voluntary or paid labor. At the higher order, participation meant that communities either defined the ends themselves, or at least had a substantial input in defining them.

**Figure 7.** Degree of participation for managing groundwater (adapted from Arnstein, [17]).

Pretty [18] suggested that two overlapping schools of thought and practice have evolved. One views participation as a means to increase efficiency, with the central notion that when people are involved, they are more likely to agree with and support the new development or service. The other view sees participation as a fundamental right, in which the main aim is to initiate mobilization for collective action, empowerment and institution building. In an analysis somewhat similar to that of Arnstein [17], Pretty [18] notes that participation has been used to justify the extension of and control by the state, as well as to build local capacity and self-reliance; it has been used to justify external decisions, as well as to devolve power and decision-making away from external agencies; and it has been used for data collection, as well as for interactive analysis.

In this study we felt the problems Shah [4] had identified were due to participation being at level A, while we would use community engagement to strive to achieve level (B), but also developing local capacity to move to level C (Table 2). It is considered that we have achieved level B participation and that this is continuing to strengthen as the project matures. As research results become available and are shared through the community engagement processes, notably via the BJs, it is hoped that the options for improvement to ensure groundwater sustainability will be taken up and lead to the emergence of level C participation.


**Table 2.** A selection of the typology of participation: How people participate in development programs and projects (adapted from Pretty [18]).

### **7. Concluding Remarks**

Sustainable groundwater use is a wicked problem and has technical, social, economic, policy and political dimensions. The access to groundwater for the farming communities is also an emotional issue as their livelihood and survival depends on it. Availability of relevant and reliable data related to the various aspects of groundwater and developing trust and support between local communities, NGOs and government agencies are the key to moving towards a dialogue to decide on what to do to achieve sustainable use of groundwater. Technical information on water table fluctuations, groundwater balance modeling, socio-economic and other data and analyses alone will hardly have any impact on over-exploitation of groundwater resources. This study has demonstrated that transdisciplinary research, which involves people who are going to benefit, is more effective in developing a deeper understanding of issues and exploring options to improve the current groundwater situation. In particular, the involvement of local villagers through groundwater monitoring, photovoice techniques and community workshops has been valuable in generating local knowledge and capacity building.

The socio-economic analysis revealed diverse attitudes to farmers' own and neighbors' groundwater responsibilities, mechanisms to coordinate groundwater use, attitudes to MAR, information sources and preferred groundwater and MAR managing agencies. Cluster membership variance highlights three key factors in designing participatory approaches and potential ground water management instruments in the two study sites. First, design principles need to address the diversity of attitudes and motivations observed in the sampled households, by emphasizing the participation of members across the whole cluster typology. Second, a reliance on a single instrument or approach to coordinate aquifer access is unlikely to align with the diverse attitudes observed across clusters, potentially resulting in low compliance rates or antagonizing sustainable groundwater management and MAR efforts. Third, while the transaction costs and resource demands make the tailoring of instruments to correspond with cluster attributes infeasible, community consultation is likely to reveal instrument sequencing as a viable strategy to promote aquifer sustainability. Addressing these three design principles in response to the observed household diversity is likely to enhance the prospects of community participation and improve aquifer recharge and groundwater pumping coordination.

The project has demonstrated that the harnessing of local experience and the indigenous knowledge of villagers has been useful in understanding the real issues of groundwater management, the geology of the area and groundwater use and changes over time. This engagement also helped in creating awareness about the project and sensitizing the community about the concept of groundwater management. The community is well aware that their groundwater is depleting at a fast rate but they were not aware of the technical reasons behind it. Local villagers had the perception that by digging deeper tubewells they would have more water, but they were not examining the issues related to groundwater recharge and water quality management. The regular monitoring of wells by BJs and the subsequent community meetings and the presence of project staff in the two study areas has now prompted the communities to talk among themselves about the future of their groundwater resources and the need to find options for managing and using groundwater more sustainably.

Efforts have been made by various government and NGO's for the augmentation of the water table, but this has not been enough to ensure long term sustainability. There is a need to awaken the people to take up groundwater recharge and rainwater harvesting and also manage demand and make irrigation more efficient. This is where the local administration must take responsibility and ensure that villagers are fully involved in such schemes. Planning is required at the micro level using participatory approaches to make each village self-sufficient in water.

### **Acknowledgments**

Funding for this research was provided by the Australian Centre for International Agricultural Research, Canberra, Australia, and we appreciate the support of Evan Christen, Research Program Manager, Land and Water Resources during this study. Thanks to Joycelyn Applebee, Sita Ram Bhakar, Pradeep Bhatnagar and Anand Singh Jodha for their assistance during the study.

### **Author Contributions**

Data collection, analysis and writing: Basant Maheshwari, Ramesh Purohit, Hakimuddin, Tushaar Shah, Peter Dillon, Maria Estela Varua, John Ward, Roger Packham and Pennan Chinnasamy.

Mainly data collection and analysis: Yogita Dashora, Seema Dave, Prahlad Soni, Sachin Oza, Pradeep Singh, Sanmugam Prathapar, Ashish Patel, Yogesh Jadeja, Brijen Thaker, Rai Kookana, Harsharn Grewal, Kamal Yadav, Hemant Mittal, Michael Chew and Pratap Rao.

### **Conflicts of Interest**

The authors declare no conflict of interest.

### **References**


## **Policy Preferences about Managed Aquifer Recharge for Securing Sustainable Water Supply to Chennai City, India**

**Norbert Brunner, Markus Starkl, Ponnusamy Sakthivel, Lakshmanan Elango, Subbaiah Amirthalingam, Chinniyampalayam E. Pratap, Munuswamy Thirunavukkarasu and Sundaram Parimalarenganayaki** 

**Abstract:** The objective of this study is to bring out the policy changes with respect to managed aquifer recharge (focusing on infiltration ponds), which in the view of relevant stakeholders may ease the problem of groundwater depletion in the context of Chennai City; Tamil Nadu; India. Groundwater is needed for the drinking water security of Chennai and overexploitation has resulted in depletion and seawater intrusion. Current policies at the municipal; state and national level all support recharge of groundwater and rainwater harvesting to counter groundwater depletion. However, despite such favorable policies, the legal framework and the administrative praxis do not support systematic approaches towards managed aquifer recharge in the periphery of Chennai. The present study confirms this, considering the mandates of governmental key-actors and a survey of the preferences and motives of stakeholder representatives. There are about 25 stakeholder groups with interests in groundwater issues, but they lack a common vision. For example, conflicting interest of stakeholders may hinder implementation of certain types of managed aquifer recharge methods. To overcome this problem, most stakeholders support the idea to establish an authority in the state for licensing groundwater extraction and overseeing managed aquifer recharge.

Reprinted from *Water*. Cite as: Brunner, N.; Starkl, M.; Sakthivel, P.; Elango, L.; Amirthalingam, S.; Pratap, C.E.; Thirunavukkarasu, M.; Parimalarenganayaki, S. Policy Preferences about Managed Aquifer Recharge for Securing Sustainable Water Supply to Chennai City, India. *Water* **2014**, *6*, 3739-3757.

### **1. Introduction**

In India, as well as in many other countries (e.g., China [1]), overexploitation of groundwater is a serious problem. It has caused declining groundwater levels, deterioration of water quality, and in coastal regions intrusion of seawater. Such a situation may lead to a race for pumping water for irrigation, which accelerates groundwater depletion and ends in a "tragedy of the commons" [2,3]. This becomes evident by higher energy costs for pumping irrigation water: In India, energy for farmers is subsidized (diesel, electricity) or given free and the escalation of subsidies for agriculture burdens government budgets [4].

To overcome groundwater depletion and the associated costs, governments may support managed aquifer recharge (MAR). MAR is the purposeful recharge of water to aquifers for subsequent recovery or environmental benefit, such as rainwater harvesting (RWH), infiltration ponds, or check dams. These are considered in this paper, as they generate water supplies from sources that may otherwise be lost due to runoff [5–8]. MAR also has the aim of preserving or improving groundwater quality. Related groundwater management actions can include substituting alternative water sources for groundwater (the paper considers desalination) and "non-structural policy measures", by which the paper means demand management to promote water conservation (e.g., by water pricing or state sponsored incentive programs to reduce cropping; [9] is an early example).

The basis of this study is a water supply scenario for Chennai, where overexploitation of groundwater has become a threat to drinking water security [7]: "Chronic water shortages mark the norm in this city." Thereby, for the state of Tamil Nadu the legal framework provides a favorable atmosphere for groundwater management, making e.g., RWH on roofs mandatory since 2001. Also present water polices of India are favorable, acknowledging MAR as an important tool for sustaining water supplies for all kinds of users [10]. However, MAR involves multiple agencies, which may not always cooperate or share information [11]. At the same time, there are many different stakeholder groups and their interests in groundwater recharge, groundwater use, or quality of groundwater may not be compatible with each other; rather multiple conflicts of interests (e.g., urban *vs.* peri-urban and rural) are to be expected [12,13].

Therefore, the paper focuses on the perception of these stakeholder groups on MAR, considering the broader context of groundwater management. It also asks, which policy changes the stakeholders deem necessary to implement a specific MAR approach, namely the construction of many small infiltration ponds.

### **2. Background Information: Current Water Supply and Future Options**

Chennai City (formerly Madras) is the capital of Tamil Nadu state. With 4.7 million people (2011 census) and an area of 426 km2 it is the sixth largest city in India. (Official statistics refer to the old boundaries prior to the expansion of city limits in the year 2011.) With a larger metropolitan area of 1189 km2 and nine million people, it is the fourth largest metropolitan agglomeration in India. The Chennai Metropolitan Water Supply & Sewerage Board (CMWSSB), a statutory body established in 1978, is responsible for water supply and sewerage functions. It operates in the city, only, but is expected to gradually extend its services to the entire metropolitan area.

Over 90% of the water supply of Chennai is covered by water stemming from reservoirs, which are depending on the monsoon rains ([14] and Figure 1). When the reservoirs are empty then the water to the city is mostly met by groundwater to cover the gap in water supply. However, due to exploitation of the groundwater resources (pumping of groundwater for domestic, industrial and agricultural water supply), the contribution of groundwater to the water supply of Chennai has diminished, from a maximum of 25% to around 6% during 2000. At the beginning of the 2013 summer season (March 2013) the share of groundwater was as low as 1% [14]. This indicates over-dependence on all current sources to meet Chennai's water supply. Further, the decline of the groundwater level has led to the intrusion of seawater in the coastal area.

**Figure 1.** Reservoirs around Chennai.

Conventional technical approaches to overcome the water shortages during summer were the construction of new reservoirs (e.g., Veeranam Lake Water Supply Project, commissioned in 2004), the increase of the capacity of existing reservoirs, and the provision of desalination plants. The Telugu Ganga Project diverts water from Krishna River in Andhra Pradesh to Chennai. Also, water pricing is practiced; however, in comparison with other cities such as Bangalore and Hyderabad only few households have functioning meters [15].

In addition, MAR has been practiced to replenish the aquifer and to mitigate seawater intrusion. Thereby, MAR was considered for replenishing the local aquifer at acceptable costs in order to "build a credit that can be drawn on in drought" [16]. Indeed, mitigation of seawater intrusion by MAR in the aquifers north of Chennai was observed by [17]. Thereby, in Tamil Nadu State RWH in all buildings is mandatory. Further, there has been a popular movement for the revival of traditional structures, e.g., Oorani for RWH or temple tanks for groundwater recharge. Two other technologies for MAR have been implemented: check-dams and infiltration ponds.

With respect to infiltration ponds there is one pilot study, implemented by Anna University. To be effective, a large number of small ponds would be required and a preliminary survey has shown that around 10,000 percolation ponds are feasible in the Arani and Koratallai river basin north of Chennai. Initial results indicate that approximately 40% of water stored in an infiltration pond may be recharged.

Similar figures about recharge were published for check dams [18]. Their overall storage capacity shall be 31 million m3 , with capacities ranging from 0.2 to 2.87 million m3 . Currently, there are nine dams at Arani River (4.42 million m3 ), seven at Kortallai River (3.4 million m3 ) and three at Palar River (5.18 million m3 ). At Arani and Kortallai Rivers 71% of the planned capacity is implemented. Check dams at Palar River have lower priority, as the city depends only in extreme droughts on water from that river basin, which is at a distance of about 80 km.

Table 1 informs about the costs of recent projects.



Note: Data are drawn from project reports. These values were considered suitable for initiating discussion on stakeholder opinions, but should not be relied on for estimating actual costs of the respective types of infrastructure.

### **3. Problem and Goal**

This paper studies stakeholder perceptions in Chennai about groundwater management. It compares their views about three MAR options (roof top RWH in urban areas, large check dams and small infiltration ponds) with other approaches to overcome the problem of groundwater depletion due to over-exploitation, such as conventional infrastructure solutions (building or enlarging reservoirs), desalination, and non-structural policy instruments (e.g., water pricing). With respect to these options, the paper presents the interests, preferences and motivations of representatives of stakeholders at the national, state, municipal and individual levels, who took part in two workshops.

### **4. Method**

A preliminary study identified the most relevant local stakeholders, in particular the governmental key-actors with interests in groundwater use, recharge, and quality (Table 2). Subsequently, the perceptions and preferences of stakeholder representatives for about six options to secure the future water supply for Chennai were explored, based on two workshops. Stakeholders interested in the topics (first workshop about options to secure water supply for Chennai, second workshop about infiltration ponds) were contacted and invited to participate. Thereby, "stakeholders" at the national, state or municipal levels are government agencies involved in water governance, while at the local and individual level these are groups of persons, companies or organizations in the Chennai area with a concern for groundwater related issues.


**Table 2.** List of stakeholders.

A first workshop was conducted with participants from government and civil society. Also, several members of the project team took part and informed the participants about the present situation (see background information in Section 2).

In particular, respondents were informed about the technical options and costs observed for recent projects (Table 1): Increasing the capacity of existing reservoirs and groundwater recharge by infiltration ponds are most economical. The subsequent plenary discussions focused on the legal situation and on implementation aspects. At the end of the workshop, 25 respondents answered a questionnaire about the opinions concerning different groundwater management approaches, about the relevant criteria to assess these approaches, and about the opinions concerning different policy approaches.

The output of this workshop was used for the subsequent discussion of the legal and policy issues of implementing infiltration ponds in the area surrounding Chennai, mapped in Figure 1.

The project team presented these results at another workshop with representatives from government organizations and civil society. Again, at the end of the workshop 29 questionnaires were answered. (Respondents of the survey at the first workshop did not take part.) In addition to the previous questions about groundwater management approaches and criteria to assess them, a set of questions inquired specifically about infiltration ponds as well as legal and policy issues to implement them.

Participants of the workshops came from stakeholders groups, who could be decisive for MAR implementation. For the government (Table 2 for the abbreviations), these were members of the Chennai branch of CGWB for the central government; from Madras High Court for the jurisdiction, from several government departments (e.g., TNWSDB, Chennai, TNPWD, Chennai) of Tamil Nadu State; and from CMWSSB, Chennai, for the city. From civil society, there were representatives from business (e.g., consultants, advocates), NGOs (e.g., Alacrity Foundation, Chennai, DHAN Foundation, Chennai), and students and scientists from research institutions (e.g., Anna University, Chennai, Tamil Nadu Dr. Ambedkar Law University, Chennai). At both workshops, farmers took part, whose land might be used for MAR structures.

The surveys were conducted in the context of the future water supply needs of Chennai. For the interpretation, it should be recalled that the surveys were not intended to be representative opinion polls for any specific group, and *no concrete decision should be prepared*. Rather, these were explorative studies, where samples of 10–30 respondents suffice [19].

In particular, the sample was not representative for the population at large: 11% were women and the median age was 51, ranging from 20 to 37 for women and 25 to 71 for men. Further, 38% were from government or courts, 15% from research institutions, 19% experts from (other) NGOs, and 27% were farmers, some without education. To ensure their inclusion and to avoid misunderstandings of the questions, members of the project team (they did not take part in the survey) assisted the respondents in filling the questionnaires.

In order to identify explanatory structure, the survey data were processed by methods of pattern recognition, data mining, and social network analysis, using preferably non-parametric tests suitable for small sample sizes. The significance level was uniformly 95% (with the Bonferroni correction for significance of multiple comparisons, e.g., Milton Friedman's test). For one-sided 95% confidence intervals, Clopper-Pearson method (based on the inverse beta-distribution) was used, as it is conservative (higher confidence than stated as the nominal level). Software used was Microsoft Excel, XL-STAT of Addinsoft for statistical tests and data mining (an add-in to Microsoft Excel) and UCINET 6 of Analytic Technologies for social network analysis. In future decision making and project planning, accommodating and acknowledging stakeholder input and feedback will be important for a successful implementation and these methods may be applied again for such analysis.

### **5. Results**

### *5.1. Stakeholder Survey*

This section lists 25 stakeholders (Table 2) and summarizes their interests in groundwater issues (Figure 2).

**Figure 2.** Stakeholders and their groundwater-related interests.

Notes: (2-mode network, using UCINET 6): Grey squares are groundwater-related interests; "GW quality" = pollution control of groundwater, "GW use" = extraction of groundwater, "GW recharge" = RWH or other MAR infrastructure, "Other issues" = water saving by the use of recycled water or similar questions. White circles represent stakeholders (abbreviations explained in Table 2), whereby lines connect stakeholders to their interests.

For governmental stakeholders, the interests are defined from the mandate (*i.e.*, laws and policies). For instance, as GoI delegated to the states groundwater responsibilities [20], and as the municipalities are responsible for actual water provision, at all levels of government there is an interest in all groundwater issues. More specialized government institutions have more restricted interests (Figure 2).

For institutional non-governmental local stakeholders (companies, universities, water user associations and other organizations), interests in groundwater issues, also indirect ones (e.g., industry, with direct interest in groundwater extraction, but not necessarily in recharge), were inferred from their business, research or other activities. For instance (with respect to CSOs), media regularly inform the public about the depletion of groundwater and sea water intrusion, and about advantages of groundwater recharge. The same is true for certain NGOs, such as local groups against sale of groundwater in the villages around Chennai [21].

For groups of individual stakeholders (e.g., farmers, peasants, residents), the interests were figured out from their needs.

### *5.2. Comparing Acceptance for Water Supply Options*

The results of this subsection are based on two stakeholder workshops and the subsequent surveys with 54 responses, of which 50 could be used, as all relevant questions were answered.

Stakeholders were asked about the acceptance of six approaches: increasing the capacity of reservoirs (representative of conventional approaches), desalination, non-structural policy instruments (such as water pricing), and MAR through RWH, check dams, and infiltration ponds. The options were chosen, because they were practiced or considered in the political discourse in the context of water saving and recovery, drinking water security, and groundwater recharge. (RWH is mandatory, reservoirs, desalination, and check dams are common, infiltration ponds and water pricing are discussed.) Further, they are typical instruments for different policy and technology approaches, and they operate at different scales.

Respondents were asked to assess the potential of the different options for securing the water supply (very high, high, low, very low) and to rank the options in terms of their individual preferences (from 1 = highest preference to 6 = lowest), using the "1224 competition ranking" (rank function of Microsoft Excel) to handle equals. From these answers, *low acceptance* (–1) of an option for a stakeholder was defined, if it was of low or very low potential and the ranking was five or six, and *high acceptance* (+1) was defined symmetrically (high or very high potential and rank one or two); the other answers were interpreted as *indifference* (0).

Summarizing the confidence intervals (Table 3), except for desalination plants and non-structural policies with low acceptance for at least ¼ of stakeholders, all other options appeared to be acceptable. Infiltration ponds were neither strongly supported, nor disliked by many.


**Table 3.** One-sided 95% Clopper-Pearson confidence intervals for acceptance of options.

Comparing also the distribution of the acceptance levels of each two options (Figure 3), desalination and policies had with 95% significance stochastically lower acceptance than RWH, building new check dams or enlarging reservoirs. For infiltration ponds (37 indifferent respondents) there were no significant differences in acceptance to any other option.

**Figure 3.** Pair-wise tests for differences in acceptance.

Notes: Based on 50 responses, nodes represent options for securing water supply and links indicate, that "there is no 99.7% significant difference by Friedman's test", as computed with XL-Stat (correcting significance for 15 pair-wise comparisons). Colors identify two K-cores (clique-like structures) and node size is by closeness (a measure of centrality, which identifies far-off and thus rather different options), as computed with UCINET 6. The positions indicate lower acceptance to the right.

### *5.3. Stakeholder Motivations*

The results of this subsection are based on two stakeholder workshops with 54 respondents.

Again, from 54 responses 50 were used, as they answered all relevant questions. To explore the motivation, respondents were asked to rank key-criteria by importance. As expected, on average human health (water quality) was most important, followed by the impact on the environment, social aspects (equity), impact on economy (costs, development), and practical issues (implementation, readiness of institutions). While between two consecutive criteria (e.g., health and environment) the difference was not significant, the criterion after the next one (e.g., social compared to health) had a stochastically higher (*i.e.*, worse) rank for importance (Friedman's test at 99.5% significance to correct for 10 pair-wise comparisons).

The 50 responses that answered all questions about the ranks of criteria and about the potentials, ranks, and acceptance of options were positively correlated, which indicates some consensus amongst respondents. A cluster analysis based on high correlations identified 22 respondents ("cluster respondents") with similar views (Figure 4). However, it also singled out 28 "non-cluster respondents", of them 22 idiosyncratic (no high correlation to any other response) and six almost idiosyncratic (highly correlated to only one other response). Regression trees (using XL-Stat) characterized the cluster-preferences (see [22] for atypical responses): Typically, 91% of the cluster respondents (20 of 22) had low acceptance for desalination and they ranked health first or second. Non-cluster respondents were expected to be more diverse, but typically, 68% of the non-cluster respondents (19 of 28) were indifferent or positive (high acceptance) about desalination and indifferent or negative (low acceptance) about check dams.

**Figure 4.** Cluster analysis of respondents to identify consensus.

Notes: Nodes labeled S and T denote participants of the first and second workshops respectively. Based on the preferences for options (potential, rank, and acceptance) and criteria (importance rank), for each pair of responses the correlation coefficient was computed. Links indicate a 99.99% significant positive correlation coefficient of 0.9 or higher between responses (*T*-test, XL-Stat). For the figure, 22 isolated responses were removed (not highly correlated to any other response) and for six (white) nodes there is a link to one other node only. The remaining 22 nodes identify "cluster respondents" with similar views. Within this group, 14 black nodes represent a K-core (a clique like structure), of them 50% farmers, and 8 grey nodes peripheral respondents; they would be disconnected upon removal of a node (computations with UCINET 6).

### *5.4. Views on Legal Regulations and Policy Instruments for Implementing Infiltration Ponds*

The results of this subsection are based on the second workshop.

For Table 4, 24 of 29 respondents answered all relevant questions (five did not). The workshop focused on the stakeholder views concerning the implementation of infiltration ponds, as in the view of the project team building thousands of small infiltration ponds would be an economically viable response to groundwater depletion, where the social group with the largest consumption of groundwater, the farmers, assume responsibility for its recharge.

Table 4 summarizes the views and displays significant differences between cluster and noncluster respondents. The majority of respondents was critical about water supply, supported "the proposal to construct thousands of infiltration ponds in agricultural areas around Chennai" (interview question), whereby the farmers should take the initiative to implement them, the government should finance a substantial share of the construction costs, and farmers should operate and maintain their infiltration ponds and be responsible for the running costs (*i.e.*, for operation and maintenance). As to the differences between cluster and non-cluster respondents displayed in Table 4, cluster respondents have seen more responsibility in all aspects with the farmers.

For Table 5, the acceptance for instruments that support implementation of infiltration ponds was explored on the basis of 26 responses at the second workshop. (Three of 29 respondents did not answer all respective questions.) Thereby, the acceptance for policies was defined from the answers about the suitability (suitable, rather suitable, rather not suitable, not suitable) and the rank (1 = highest to 5 = lowest preference; respondents could propose as fifth category "other") of the policy instruments: High acceptance means suitable and rank one or two, low acceptance means not suitable and rank four or five. Table 5 displays the acceptance. ("Other" is not displayed, as only 7 of 26 respondents considered it.) Summarizing, two policy instruments to promote infiltration ponds were acceptable: supporting ponds using public funds and providing information. Thereby, "information" was discussed in a broader context of a (participative) communication strategy, as outlined e.g., by [23]. Making infiltration ponds mandatory for farms with more than one acre (about 4000 m2 ) may be contested, with up to 32% opponents (not so much farmers) and up to 56% supporters. Rather not acceptable was fining farmers, who do not have infiltration ponds.


**Table 4.** One-sided 95% Clopper-Pearson confidence intervals for stakeholder views.


**Table 4.** *Cont.* 

Notes: Respondents could answer yes/no = ±1, and yes/no with reservations = ±0.5. "Approval" gives one sided 95% confidence intervals for the percent answering yes or yes with reservations. "Cluster difference" informs, if with 99.99% significance (Mann-Whitney test) respondents of one cluster had a stochastically higher/lower approval and different mean approval rates.


As the questions to identify needs for legal and policy changes were more specialized, respondents of the second workshop skipped certain questions depending on the expertise. (For this set of questions, 7% of 667 entries, *i.e.*, 29 responses to 23 questions, were not answered). The following percentages refer to those respondents that answered the respective questions.


groups, except "other") had with 95% significance a stochastically lower priority than civil society and farmers.


### *5.5. Specific Observations from the Workshop Discussions*

Compared to the other options, "non-structural policy instruments" was atypical, as it describes a bundle of policy instruments. In the workshops, the project team explained that this would include e.g., water pricing, banning or licensing of groundwater extraction, enforcing or supporting change to less water demanding crops, enforcing or supporting summer plowing to maintain soil humidity, or merely awareness rising amongst different target groups for issues related to water saving. However, perhaps as water pricing is practiced in Chennai (see Section 2), the discussions focused on "reducing demand by higher drinking water or irrigation water prices". Thus, for this paper "non-structural policy instruments" de facto means "water pricing and measures supporting it" (e.g., cut of energy subsidies, privatization).

For the other options, no such problems occurred. Further, although respondents of the first workshop added several proposals for mitigating water scarcity, these proposals were conceptually similar to the considered options. Amongst the proposals was metering in apartment complexes and big hotels; control of demand by licensing; to encourage water saving toilets; recycling of grey water for domestic purposes (toilet flush); to simplify water recycling by separating wastewater according to its sources; clearing silt and sand from existing ponds to help sustain groundwater

recharge; recharging storm-water and treated wastewater. Other suggestions were interlinking the rivers of Chennai and transporting water from distant sources.

For the criteria, additional questions (at the first workshop only) indicated that in applying the criteria to specific options, respondents lacked a common understanding about the meaning of the criteria. For instance, with respect to health, some approved of desalination, as it provides clean water, while others disapproved, as it does not provide natural water, which they perceived as healthy. Also for RWH, some were concerned about possible contamination, if collected rainwater was used for drinking, while others focused on other domestic uses and were not concerned. Similarly, for reservoirs and to a lesser extent for infiltration ponds, some were concerned about risks due to water contamination and dumping of waste.

In view of these experiences, the second workshop on infiltration ponds elaborated more on these criteria. However, with respect to the preferences there were no significant differences between the workshops, except for RWH: Participants of the second workshop had with 95% significance a stochastically higher acceptance for RWH than those of the first workshop (but at both workshops it was highly accepted). Perhaps, this was due to the focus of the second workshop on infiltration ponds, which are conceptually similar (small decentralized systems) to RWH.

For the legal situation, although by Table 3, RWH had highest support and least opposition, and at both workshops there was substantial criticism. Some stakeholder representatives disapproved of the mandatory implementation of RWH in every building without taking note of the different geological patterns, the different capacity of the ground to hold water, different rainfall patterns and complex groundwater usage. Stakeholder representatives of the second workshop therefore asked that regulations should allow considering the local situation (point 7 in Section 5.4).

These concerns about the consideration of the local situation apply also to the other options: If e.g., laws were requiring all farmers to build infiltration ponds, under certain circumstances such ponds may be meaningless.

Further, stakeholders reported implementation problems, as due to understaffing CMWSSB barely communicates with the public and lacks support from other stakeholders. This in turn results in deficient law enforcement: RWH structures are routinely monitored and maintained only in exceptional cases. Hence, stakeholders asked for more regular monitoring.

Similar implementation problems made current groundwater laws (point 3 in Section 5.4) inadequate: While CMWSSB denies groundwater extraction licenses for commercial purposes, the registration of wells largely failed and unauthorized extraction of groundwater is prevailing throughout the city; the offenders enjoy impunity.

### **6. Discussion**

The stakeholder surveys confirmed the known fact that a substantial fraction of stakeholder representatives was skeptical about desalination plants, which are amongst the most costly options to secure drinking water supply. Such low acceptance for desalination plants is known also from other countries, e.g., Australia [25]. In India cultural issues (also for educated populations, only spring water may be perceived as clean and healthy) aggravate this low acceptance problem.

The observed low acceptance of non-structural policies may be explained by the critical discussion of water pricing and privatization of water services. These policies are perceived critically also in other countries, e.g., Bolivia, where increases of tariffs have stirred violent public protests [26], Ghana and Tanzania [27], or South Africa [28]. There are concerns about environmental justice, as the burdens for the poor could be out of proportion [29].

Also, the high acceptance for RWH was as expected, as RWH is a traditional water supply option supported also by court judgments that repeatedly confirmed the eviction of encroachers from land used for RWH [30]. However, stakeholders had doubts about the efficient functioning of RWH structures.

The conventional approach to secure water supply is building new reservoirs. The stakeholder views on this option were not inquired, as there are limitations to new reservoirs, and to fulfill its water needs, Tamil Nadu state already operates reservoirs outside the state. This causes specific problems, as is illustrated by a recent interstate case at the Supreme Court of India [31]: Tamil Nadu state leases and operates Mullaperiyar dam in Kerala. Kerala was concerned about the earthquake-safety of the dam and enacted a state law to limit the reservoir level. In view of the consequently unmet water needs of Tamil Nadu, in 2014 the Court declared the Kerala state law as unconstitutional.

Increasing the capacity of existing reservoirs was the most economical of the considered solutions and it was generally accepted. However, stakeholders were aware that for reservoirs there is a need for regulations that consider the local situations: Vulnerable water bodies might need a higher protection than guaranteed by the national standards. A notorious example, for 15 years in courts, was the Orathupalayam dam project to use water from Noyyal River for irrigation, where five years after its completion in 1992, heavy water pollution from textile industry forced farmers to give up irrigation [32].

Groundwater recharge by check dams was the second most expensive option, but it was generally accepted and it is widely used. Conflicts about land acquisition plans may hinder the realization of such large scale infrastructure projects. This is exemplified by the delay of the construction of the Thirukandalam check dam [33]. For although landowners benefit substantially from check dams by increased yields [34], farmers fear receiving insufficient compensation for arable land that is used for such projects. Also, the survey confirmed that stakeholders were aware of the need to hear farmers, when formulating water policies (see point 2 in Section 5.4).

In terms of unit costs, infiltration ponds were second best with respect to unit costs. While the acceptance was not as clear as for the other options (see Figure 3), stakeholder representatives at the second workshop (about infiltration ponds) supported the idea to construct thousands of infiltration ponds in the rural areas surrounding Chennai (point 2 in Table 4). Farmers may at first not understand why they should give up arable land and spend money to build such ponds (just to secure the water supply of Chennai). Stakeholder representatives were aware of this problem and they approved the idea that the government should support the farmers in building infiltration ponds (Table 5 and point 10 in Table 4). Later on, the farmers should operate and maintain them without public support (points 14 and 19 in Table 4). Thereby, the implementation of infiltration ponds may also benefit from the observed high acceptance for RWH. Accordingly, infiltration ponds are small structures comparable to RWH structures and farmers will benefit from the aquifer recharge. Media reports [35] further emphasized that farmers may generate additional income from aqua-cultures (with risks for water quality).

Stakeholder representatives at the second workshop were not so critical about existing laws (many are used to apply them in administration and courts) and considered that current laws would support infiltration ponds (point 3 in Table 4).

However, in view of the workshop discussions, the majority, and also the project team, had critical views about the inadequacy of current groundwater laws and regulations (point 3 in Section 5.4). An example for the ineffectiveness of existing laws was the still applied national Easement Act of 1882 vesting owners of land with ownership of groundwater, irrespective of the rights of neighbors or public interests in groundwater preservation. Thereby, the interests of neighbors in water *de facto* have not been framed as legal entitlements or obligations. Further, national agencies (CGWB, CPCB) in charge of the implementation of national policies may not really influence actual decision making, as they tend to approve projects, which receive a "no objection certificate" from state agencies [36]. Yet, the stakeholder representatives considered that the national government should indeed have only a minor role for groundwater conservation, below state governments in importance (point 1 in Section 5.4).

For the specific problem of groundwater extraction, more than 75% of stakeholder representatives acknowledged the need to better regulate it and they supported the idea that a state authority should be in charge of MAR (points 4 and 6 in Section 5.4). Currently, different agencies of the government appear to act in an uncoordinated manner and without an integrated perspective about MAR [11]. For example, the water bodies and channels are not governed by CMWSSB, and neither are the temple tanks, which could serve as MAR structures. Another issue for the workshop was ineffective governance of groundwater, as commercial operators extract it unlawfully throughout the city.

The survey also identified a communication problem, illustrated by the lack of a common understanding of key criteria, such as health. A cluster analysis confirmed this lack of a common vision: While amongst 50 stakeholder representatives, 22 "cluster respondents" with similar preferences could be identified (Figure 3), the other 56% of respondents were almost idiosyncratic and perhaps unfavorable to MAR; e.g., the "typical non-cluster respondent" was indifferent or negative with respect to check dams.

### **7. Conclusions**

Groundwater is an important source of domestic water supply in Chennai during the regular droughts and the peri-urban villages depend completely on groundwater. As agriculture and industry have been overexploiting groundwater, which is evident from the lowering of the water table and the intrusion of seawater, more effective instruments would be needed to control the extraction of groundwater and the use of water.

The paper investigated several feasible approaches, amongst them two MAR options, namely to build large check dams or many small infiltration ponds.

For the considered options, urban RWH is widely accepted and already mandatory, but stakeholders reported ineffective monitoring. Thus, better enforcement could make RWH more effective and better define the impact.

As to non-structural policy instruments, stakeholders identified them with water pricing and did not accept them.

Desalination plants and reverse osmosis of brackish water are too costly solutions to cover the basic demand, and consumers may not accept them.

Building new reservoirs for additional water or building check dams for groundwater recharge are costly, too, and in similar projects conflicts about land acquisition have caused substantial delays.

For the same reason, infiltration ponds could meet resistance, as thousands of ponds would be needed, but there is no legislation that would make them mandatory.

Further, for the implementation of infiltration ponds there is a coordination problem, as it would have not much effect, if only a few farmers would build small infiltration ponds: About 500 ponds would correspond to a small check dam and 10,000 to a large one. Thus, farmers would face costs, the groundwater table might barely rise, and if it rises, then farmers without infiltration ponds would be free-riders that benefit as well.

From these considerations it follows:


To solve the coordination problem, stakeholder representatives support the idea to establish an authority in the state for licensing groundwater extraction and overseeing MAR. Accordingly, the establishment of a state authority responsible for groundwater governance and MAR (TNWRRA) would support the legal and policy measures needed to implement MAR structures. Thus, in this respect, stakeholders basically support the National Water Policies, where such instruments have been proposed. Of course, stakeholders did not envision merely another organization amongst the many existing ones, but wanted to see all groundwater responsibilities amalgamated.

### **Acknowledgments**

Co-funding to the collaborative project "Enhancement of natural water systems and treatment methods for safe and sustainable water supply in India—Saph Pani" (www.saphpani.eu) from the European Commission within the Seventh Framework Programme (grant agreement number 282911) is gratefully acknowledged.

### **Author Contributions**

All authors are equally responsible for the conception of the paper. The CEMDS team was responsible for the data analysis and legal analyses, the Anna University team for the factual information and all Indian authors for the information acquisition from the workshops.

### **Conflicts of Interest**

The authors declare no conflict of interest.

### **References and Notes**


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