1. Introduction
This study analyzes the economic aspects in the DINA-MAR project related to the price of Managed Aquifer Recharge (MAR) water. These aspects range from simple ratios to advanced proposals based on GIS. This analysis was conducted to study the feasibility of implementing new building works and to provide support to decision makers in Spain. DINA-MAR (Depth Investigation of New Areas for Managed Aquifer Recharge in Spain) is a project financed by the Tragsa Group with the aim of determining the most suitable areas for MAR and how to implement MAR activities within Spain.
The use of GIS for determining opportunities for MAR is broadly mentioned in hydrogeological literature. Some other approaches have been consulted, especially in papers or reports from Portugal, India, Australia and Italy, which provide a different GIS mapping approach than the one displayed in this article.
A regional scale study was performed by Dudding
et al., 2006, [
1], for the Melbourne region for ASR potential as well as for depth aquifers.
An explanation of the main features in relation to opportunities for water banking is exposed in Hostetler, 2007 [
2], although the aggregated features differs from specific opportunities for MAR.
Some papers from India on GIS approaches have been consulted, as for instance the analysis from Kallalia
et al., 2007 [
3] (pp. 111–119), for potential wastewater aquifer recharge sites, which assesses mapping MAR opportunities.
A GIS based expert system for selecting recharge methods is reported by Masciopinto
et al., 1991 [
4] (pp. 331–342). No reference could be found on the previous use of GIS for costing of MAR projects.
The study by Pedrero
et al., 2011 [
5] (pp. 105–116), describes a GIS-based multi-criteria analysis for site selection of aquifer recharge with reclaimed water. Another regional scale study was performed by Smith & Pollock, 2010 [
6], who evaluated the artificial recharge potential for a superficial aquifer by means of GIS in the Perth region.
Three different lines of action have been accomplished and presented in the paper to analyze the economics of MAR.
First, the investment ratios of construction costs to storage volume and the mean life of the existing MAR projects with various techniques were evaluated and compared to dam and irrigation pond costs. Numerous examples were collected for statistical analysis.
Second, an advanced GIS methodology determined the “MAR zones” in Spain. After the identification of these zones, the most ideal devices were identified according to the inventory of 24 categories that were proposed in the project [
7] (pp. 303–318).
Third, the origin of the water sources in the above two methods was considered. Water resources originating from either fluvial or sewage waters were then compared. Both of these water sources were budgeted.
The fluvial water is provided by a diversion structure in a river to an adequate aquifer for underground storage. Different premises have been considered according to the available flow, ease of application, suitability studies, feasibility studies and cost including exploitation and maintenance expenses. The sewage water option injects reclaimed water into deep boreholes and wells that are generally located near a sewage treatment plant. Economic studies have considered water flow, tertiary treatment, desalination, method of recharge to aquifers, construction costs, conservation costs, study costs and project costs.
Using the maps of potential sites or “MAR areas” for MAR in the Iberian Peninsula and Balearic Islands of Spain and the results of economic studies as the starting point of this study, we proposed a new specific mapping of the total expected costs for all “MAR zones” (€/m3) that depended on the most appropriate device for each case. This novel mapping provides guidelines that are intended to be valuable for water managers and practitioners for future development of Managed Aquifer Recharge projects.
2. Materials and Methods
The methodological approach consisted of a GIS study based on ARC/GIS and DINA-MAP programs. This process determines the most appropriate areas in Spain to apply MAR techniques with potential fluvial or waste waters.
The process is recursive because the method tests different algebraic map options on constructed maps with up to 83 layers and GIS coverage. Various parameters such as permeable outcrop layers, lithology, aquifers, water levels, fluvial riverbeds, water purifying plants, data collection stations with flow-rate measurements, slopes, altitudes, and distance to the coasts have been loaded in the system and taken into consideration (
Table 1 and
Figure 1).
To identify the MAR zones, 11 chloropeth maps of hydrographic basins were created. An example of the results for one of the most prospective basins is shown in
Figure 2. The entire map series is available at DINA-MAR website [
8].
This deductive process supported by algebra maps and analysis in GIS has two major drawbacks in information processing: different projection systems and an incorrect boundary overlay of the layers and thematic coverages used. An effort to unify the map was required.
Table 1.
Relating “Managed Aquifer Recharge (MAR) zones” by hydrographic major basins. Columns: basin name, the MAR zone area contained in the basin, the basin area, the percentage of the basin covered by a MAR zone and the percentage of an individual MAR of the total MAR area.
Table 1.
Relating “Managed Aquifer Recharge (MAR) zones” by hydrographic major basins. Columns: basin name, the MAR zone area contained in the basin, the basin area, the percentage of the basin covered by a MAR zone and the percentage of an individual MAR of the total MAR area.
ID | Major basin | MAR Zones Areas within Basin (km2) | Total Basin Areas (km2) | % MAR Zones/Basin | % Total |
---|
1 | NORTH | 1,953 | 53,781 | 3.6 | 2.9 |
2 | DUERO | 21,565 | 78,955 | 27.3 | 32.3 |
3 | TAGUS | 10,186 | 55,815 | 18.2 | 15.2 |
4 | GUADIANA | 5,184 | 60,125 | 8.6 | 7.7 |
5 | GUADALQUIVIR | 4,878 | 63,298 | 7.7 | 7.3 |
6 | SOUTH | 1,458 | 18,408 | 7.9 | 2.2 |
7 | SEGURA | 2,283 | 18,833 | 12.1 | 3.4 |
8 | JUCAR | 7,892 | 42,682 | 18.5 | 11.8 |
9 | EBRO | 8,686 | 85,936 | 10.1 | 13.0 |
10 | PYRENEES | 1,746 | 16,555 | 10.6 | 2.6 |
11 | BALEARIC | 1,023 | 5,038 | 20.3 | 1.5 |
| Total | 66,854 | 499,428 | 13.4 | 100 |
In total, 23 main layers were employed with the assigned original number as follows:
- -
Geology of Spain, scale 1:200 000. MMA, 2006;
- -
Control of nitrates in the groundwater network;
- -
Vulnerable areas to nitrates;
- -
Irrigated areas and source of water;
- -
Concentric polygons around rivers and reservoirs;
- -
Risk of flooding;
- -
Tilt cartography;
- -
Tagus-Segura aqueducts;
- -
Quality of water: conductivity;
- -
Mines into aquifers. MMA, 2006;
- -
Groundwater piezometric monitoring network;
- -
Forest mapping for Spain, scale 1:50 000);
- -
Hydrogeological units;
- -
Sewage treatment plants;
- -
Detailed urban areas;
- -
Marine intrusion control network;
- -
Altitude;
- -
Dry wetlands;
- -
Watersheds with water surplus;
- -
Distance from shore;
- -
Dune systems;
- -
Administrative boundaries;
- -
Current MAR sites.
Figure 1.
Location map of the operative Managed Aquifer Recharge (MAR) sites in Spain.
Figure 1.
Location map of the operative Managed Aquifer Recharge (MAR) sites in Spain.
Figure 2.
Example of the distribution of “MAR zones” in the Spanish Jucar basin.
Figure 2.
Example of the distribution of “MAR zones” in the Spanish Jucar basin.
The main objective of this study was to identify a process producing similar results in existing inventories. The “MAR zones” in Spain were defined after several trials. The procedure that best represented these MAR activities in Spain was adopted (detailed explanation of this process in DINA-MAR, 2010 [
7]). The pixel size for map overlays was 1 km × 1 km.
To determine the ideal devices for each “MAR zone”, an inventory of 24 devices previously proposed (
Figure 3) was distributed and classified according to their characteristics and their most suitable environments.
Figure 3.
Inventory of feasible and applicable MAR devices, modified from Fernández & San Sebastián [
9] (pp. 5–6).
Figure 3.
Inventory of feasible and applicable MAR devices, modified from Fernández & San Sebastián [
9] (pp. 5–6).
Numerous “if-then” conditions were designed into the system for each device or technique to obtain a group of ranked results for each area according to the specific conditions (
Table 3).
A system of grades-weights was applied after studying each device individually; these values are presented in the “weight” column in
Table 2.
Table 2.
Initial indicator to determine the suitability of MAR techniques according to costing based on the ratio between the investment costs and the initial storage volume. Mean costs taken from Tragsa Group projects performed for the Spanish Ministry of Agriculture.
Table 2.
Initial indicator to determine the suitability of MAR techniques according to costing based on the ratio between the investment costs and the initial storage volume. Mean costs taken from Tragsa Group projects performed for the Spanish Ministry of Agriculture.
MAR facilities | Number of projects costed of this type | Mean investment cost ratio (€/m3) |
---|
Ponds | 18 | 9.75 |
Dams | 16 | 0.80 |
Surface MAR facilities (ponds, channels) | 8 ponds/58 km channel | 0.21 |
Deep boreholes | 4 | 0.58 |
Medium-deep boreholes | 25 | 0.36 |
After classifying the building projects performed by the Tragsa Group for the Spanish Government according to the origin of the water, a new specific mapping was proposed for total expected costs for all “MAR zones” (€/m3). This map depended on the most appropriate device for each case and featured a series of alternatives sorted according to technical suitability and cost.
The final map viewer is called “HydroGeoportal DINA-MAR” and is available at DINA-MAR “Visor cartográfico” website [
10].
3. Results and Discussion
3.1. Investment Ratios of Building Costs against Storage Volume
The initial indicator to determine the suitability of MAR techniques according to costs was based on the ratio between the investment costs and the initial storage volume. The mean life of the devices was evaluated and compared to the cost of dams and irrigation ponds that have a 25 year lifespan.
The examples considered in this study were buildings constructed by the Tragsa Group for the Spanish Ministry of Agriculture for 18 irrigation ponds and 16 medium size dams versus the ratios for MAR facilities in the Arenales Aquifer (four projects) for surface infiltration facilities and in the Guadiana basin for 25 medium-depth infiltration boreholes.
Data for MAR deep boreholes was collected from Spanish water supply companies.
Mean Investment Ratios
Data sets were treated by statistical methods (eliminating the maximum and the minimum,
etc.). The resulting ratios are as described in
Table 2.
According to these results, the MAR technique results are rather cheap for basic economic indicators in comparison with other water management techniques.
3.2. Advanced GIS Methodology Based on Linear Combination of Map Layer Attributes
3.2.1. Previous Legal Considerations
In Spain, the legal and technical framework is suited to integrate more MAR devices in water management schemes, although several implementation issues remain: Currently, regulations consider MAR as a spill, which is an obstacle to the development and the implementation of this technique. Royal Decree 1620/2007 is too restrictive in terms of water quality whereas the regulations in other countries are more permissive. The laws in these other countries consider the sanitation aspects of MAR and do not regulate several effects such as the changes in sodium concentration during deep injection.
3.2.2. Determining “MAR Zones” in Spain
The main aim of this project was to determine the most suitable areas for MAR in Spain (excluding the Canary Islands on which desalination is the typical water management technique). The calculation methodology is summarized in the previous section. A detailed description may be found at DINA-MAR, 2010 [
1] (pp. 215–216).
From the results, approximately 16% (67,000 km2) of the Spanish peninsular and Balearic Islands territory is suitable for recharge management. The most ideal basins are the Duero and Balearics basins, and the least ideal are the North and Guadalquivir basins.
The determined “MAR zones” or areas notably suitable to apply MAR activities are grouped by hydrographic basins in
Table 1.
3.2.3. Potential for the MAR Technique in Spain
Based on the premise defined by DINA-MAR that the future of water depends on the storage capacity, the storage potential of currently unsaturated Spanish aquifers was compared to the storage capacity of dams.
Based on the storage in dams in Spain in January 2005, which reached 53,198 hm3, and the definition of the MAR zones, a GIS was used to compare the capacities based on the water level depth, aquifer permeability and storage coefficients. Spanish subsoil (excluding the Canary Islands) was found to have a storage capacity of, approximately, 2.0 hm3/km2 in the MAR zones. Therefore, approximately 260% of the stored volume in the dams could be stored in aquifers in safeguarding the quality and utility of the water. Utilizing underground storage would also enable surface occupation of the land.
Despite the uncertainty inherent in the calculations, these figures indicate the high potential for MAR activities in Spain to provide new integrated water management schemes.
3.2.4. Search Criteria Used to Associate Devices with Each “MAR Zone”
With the physical elements well defined and the specifications of the 24 inventoried AR techniques known (
Figure 3), determining the most suitable technique was performed by a grades/weights system as the main association criteria. This system was designed and automated in such a way that each device receives a weight according to its suitability. This score is adjusted to the physical characteristics and other indicators with GIS support.
The established grades are the distribution of permeabilities, lithologies, nitrate contaminations, irrigable areas, irrigation origin, proximity to forests, purifying plants (with treatment types), dams (with associated capacities), wetlands, rivers (with average associated flows), distance to the coast, major aqueducts, slope, height, flood risk, water level, water quality, meteorological stations with sufficient rainfall or streamflow and urban areas. The weights range between zero (inadequate) and three (highly favorable).
By establishing a relational structure between physical factors and indicators with GIS support for MAR devices, an association matrix that supplies the HydroGeoportal DINA-MAR (
Table 3) was designed and automated.
The weight columns appear to be subjective based on the suitability of each device. Because of the important role that the devices hold in the final ranking, additional criteria are adopted to minimize the subjectivity and are presented as ranges (
Table 3, column 3). The ranges have been defined by the breakdown of each “layer” in different classes, generally distinguishing the different major types and establishing relevant groups to work with a reduced number of types. For example, the “water origin” layer distinguishes five types: surface water, groundwater, irrigation returns, water from treatment plants and water from desalination plants.
The weights (
Table 3, column 4) appear in hierarchy according to their suitability and fit to the physical characteristics and remaining indicators. The weight assigned to each case and code directly intervenes in the process of SIG calculation because the database is associated with the calculation engine; then, an individual score is assigned to each polygon. For example, the calculation method to score device D1 (infiltration pond) is as follows. First, the fields D1, D2..., D24 are included in the layer in which all layers have been previously crossed to calculate the score for each device in these fields. The crosses table is then connected to the different facilities leader board, starting with the permeability, and D1 is calculated. Successive “joins” must be performed for each of the topics, and the formula of ranges-weights is applied to obtain a final value.
This process automatically calculates a score for each of the 24 techniques and the highest score determines the most appropriate technique.
The result is a large-scale map ranking the most to the least recommended devices (
Figure 4).
The results of these calculations are expressed in the “Favorable Device” map (
Figure 4).
This system has enabled several highly ideal MAR zones to be identified. For example, up to 11 MAR devices could be concentrated in the Lower Guadalhorce aquifer (Malaga) when water is withdrawn from the river and a wastewater treatment plant (
Figure 5).
Table 3.
Relating physical factors and indicators (based on GIS support) for different MAR devices.
Table 3.
Relating physical factors and indicators (based on GIS support) for different MAR devices.
Mar techniquesand devices | | | | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 |
---|
Mar zones | | | | Dispersion | Channels | Wells | Filtrat. | Rain | Suds |
---|
| cases 1 | code | weight | infiltration ponds/ wetlands | channels and infiltration ditches | ridges/ soil and aquifer treatment techniques | infiltration fields (flood and controlled spreading) | accidental recharge by irrigation return | reservoir dams and dams | permeable dams | levees | riverbed scarification | sub-surface/ underground dams | drilled dams | qanats (underground gallerys) | open infiltration wells | deep wells and boreholes | boreholes | sinkholes, collapses | asr | astr | river bank filtration (rbf) | interdune filtration | underground irrigation | rainwater harvesting in unproductive | accidental recharge pipes and sewer system | sustainable urban drainage systems |
permeable outcrops mma2006 | | very high | 3 | 3 | 3 | 2 | 3 | 2 | 3 | 2 | 2 | 3 | 1 | 2 | 1 | 3 | 3 | 1 | 3 | 1 | 1 | 1 | 3 | 1 | 1 | 1 | 1 |
high | 2 | 3 | 3 | 1 | 3 | 2 | 2 | 2 | 3 | 2 | 1 | 2 | 1 | 3 | 3 | 1 | 1 | 1 | 1 | 1 | 3 | 1 | 1 | 1 | 1 |
medium | 1 | 2 | 2 | 1 | 1 | 2 | 2 | 2 | 1 | 1 | 1 | 2 | 1 | 2 | 2 | 1 | 1 | 3 | 3 | 1 | 2 | 1 | 1 | 1 | 1 |
geology of spain. escale 1:200.000, mma 2006 | | aluvial | 7 | 3 | 3 | 2 | 3 | 1 | 3 | 3 | 3 | 3 | 3 | 3 | 1 | 3 | 3 | 3 | 0 | 3 | 3 | 3 | 0 | 1 | 1 | 1 | 1 |
detritic | 5 | 3 | 3 | 2 | 1 | 1 | 2 | 2 | 1 | 0 | 3 | 3 | 3 | 2 | 2 | 3 | 0 | 3 | 3 | 0 | 3 | 1 | 1 | 1 | 1 |
karstic | 6 | 2 | 2 | 2 | 2 | 1 | 3 | 3 | 2 | 0 | 1 | 2 | 3 | 3 | 3 | 2 | 3 | 2 | 2 | 0 | 0 | 1 | 1 | 1 | 1 |
metamorphic | 4 | 0 | 2 | 2 | 0.5 | 1 | 2 | 2 | 0 | 0 | 1 | 3 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 |
volcanic | 3 | 0 | 2 | 2 | 0.5 | 1 | 3 | 3 | 0 | 0 | 2 | 2 | 3 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 |
intrusive | 2 | 0 | 2 | 2 | 0.5 | 1 | 2 | 2 | 0 | 0 | 2 | 2 | 1 | 2 | 1 | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 |
evaporitic | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 2 | 1 | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 |
nitrates network for groundwater | nitrate content | <50 | 1 | 1 | 1 | 1 | 1 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
≥50 | 2 | 1 | 1 | 1 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 |
vulnerablezones 2005 | 1:vulnerable zones, 0: no vulnerable zones | | 1 | 1 | 1 | 1 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 |
water origin | | surface water | 4 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 1 | 3 | 1 | 3 | 3 | 1 | 3 | 1 | 3 | 1 | 1 | 2 | 1 | 1 | 1 |
groundwater | 2 | 1 | 1 | 1 | 0.5 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 2 | 2 | 1 | 0 | 2 | 0 | 0 | 0 |
irrigation return | 4 | 0 | 3 | 1 | 2 | 3 | 1 | 1 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
ww treatment plants | 6 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 2 | 1 | 0 | 1 | 2 | 1 | 1 | 1 | 1 | 0 | 1 | 2 | 0 | 0 | 1 |
desalination plants | 4 | 2 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1.5 | 0 | 0 | 2 | 2 | 2 | 1 | 2 | 1 | 0 | 1 | 2 | 0 | 0 | 0 |
areas up to 2 km far from dams | 1:zone 2 km dams 0 bigger distance | ≤ 2 km | 1 | 2 | 2 | 2 | 0 | 1 | 2 | 0 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 3 | 3 | 3 | 3 | 3 | 0 | 2 | 0 | 0 | 0.5 |
concentric poligons close to medium flowrate rivers (1 to 5 km) | 0–0.45 | ≤ 1 km | 3 | 3 | 1 | 3 | 3 | 1 | 2 | 0 | 3 | 0 | 1 | 2 | 1 | 1 | 1 | 3 | 2 | 3 | 3 | 3 | 0.5 | 1 | 0 | 0 | 0 |
>0.45–1.65 | >1 to ≤ 2 | 3 | 1 | 2 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | 2 | 1 | 1 | 3 | 1 | 3 | 3 | 0 | 1 | 1 | 0 | 0 | 0 |
>1.65–7.26 | >2 to ≤ 3 | 4 | 1 | 2 | 1 | 0.5 | 1 | 1 | 0 | 0 | 0 | 1 | 0 | 2 | 2 | 2 | 1 | 1 | 2 | 3 | 0 | 0 | 1 | 0 | 0 | 0 |
>7.26–27.5 | >3 to ≤ 4 | 5 | 1 | 2 | 0 | 0.5 | 1 | 1 | 0 | 0 | 0 | 0.5 | 0 | 2 | 2 | 2 | 1 | 1 | 1 | 2 | 0 | 0 | 1 | 0 | 0 | 0 |
>27.5 | >4 to ≤ 5 | 6 | 1 | 3 | 0 | 0.5 | 1 | 1 | 0 | 0 | 0 | 0.5 | 0 | 2 | 3 | 3 | 3 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 0 |
overflood risk | | no risk | 4 | 3 | 2 | 1 | 0 | 3 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 3 | 3 | 3 | 1 | 3 | 3 | 0 | 1 | 1 | 1 | 1 | 0.5 |
maximum | 1 | 0 | 0 | 2 | 3 | 0 | 3 | 2 | 3 | 3 | 1 | 2 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 2 | 1 | 0 | 0 | 0 | 1 |
mean | 2 | 1 | 1 | 2 | 3 | 0.5 | 2 | 2 | 1 | 0 | 1 | 3 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 0.5 | 0 | 0 | 1 |
minimum | 3 | 2 | 1 | 1 | 2 | 1 | 1 | 1 | 0 | 0 | 1 | 2 | 1 | 3 | 3 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 |
slope intervals | % | 0–10 | 2 | 3 | 3 | 1 | 3 | 1 | 1 | 1 | 3 | 3 | 3 | 1 | 1 | 3 | 3 | 3 | 1 | 3 | 3 | 3 | 1 | 1 | 1 | 1 | 1 |
10–20 | 2 | 2 | 2 | 1 | 0 | 1 | 2 | 1 | 1 | 1 | 2 | 1 | 1 | 3 | 2 | 1 | 1 | 2 | 2 | 0.5 | 0 | 1 | 1 | 1 | 1 |
20–30 | 3 | 1 | 1 | 2 | 0 | 0.5 | 2 | 2 | 0 | 0 | 1 | 3 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 |
30–40 | 4 | 0 | 0 | 2 | 0 | 0 | 3 | 2 | 0 | 0 | 0 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
40–50 | 5 | 0 | 0 | 2 | 0 | 0 | 3 | 0 | 0 | 0 | 0 | 2 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
areas until 1 km far away from wetlands | 1:influency zones from wetlands/ no | ≤1 km | 0.5 | 1 | 2 | 0 | 3 | 1 | 2 | 2 | 0 | 1 | 2 | 1 | 1 | 2 | 3 | 1 | 1 | 0 | 0 | 1 | 1 | 1.5 | 0 | 0 | 0 |
areas distant up to km from tagus-segura acueduct | 1:zones influency tagus-segura/ no | ≤1 km | 2 | 2 | 2 | 1 | 1 | 1 | 0 | 0 | 2 | 1 | 0 | 0 | 1 | 2 | 2 | 2 | 2 | 2 | 2 | 0 | 0 | 1 | 0 | 0 | 0 |
water quality. conductivity ›2500 us/cm | 1: zones conduct <2500 | < 2500 | 1 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 3 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 3 | 2 | 2 | 1 | 1 |
2: zones conduct >2500 | > 2500 | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 0 | 0 |
mines in aquifers. buffer 2 km | 1:zones influency mines/0:zones no influency | ≤ 2 km | 2 | 2 | 2 | 1 | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 3 | 3 | 1 | 1 | 0 | 1 | 2 | 0 | 0 | 0.5 | 0 | 0 | 0 |
land use. from corine land cover | forestry | | 1 | 0 | 2 | 3 | 0 | 0 | 3 | 3 | 0 | 0 | 3 | 3 | 2 | 1 | 0 | 0 | 3 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 |
subdesertic | 1 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 2 | 0 | 3 | 3 | 3 | 2 | 2 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
meadows and pastures | 4 | 1 | 2 | 2 | 2.5 | 2 | 1 | 1 | 1 | 2 | 0.5 | 0 | 0 | 2 | 2 | 1 | 2 | 0 | 0 | 0 | 0 | 1 | 2 | 0 | 0 |
weight according to artificiality | agrary | | 4 | 3 | 3 | 2 | 3 | 3 | 1 | 2 | 2 | 3 | 1 | 3 | 0 | 3 | 3 | 3 | 0 | 3 | 3 | 1 | 0 | 3 | 2 | 0 | 0 |
barren | | 2 | 1 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 2 | 1 | 2 | 2 | 2 | 1 | 3 | 1 | 1 | 0 | 3 | 0 | 0 | 0 | 0 |
glaciars & permanent snow | | 1 | 0 | 0 | 3 | 0 | 0 | 3 | 3 | 0 | 0 | 1.5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
wetlands | | 3 | 2 | 2 | 0 | 3 | 1 | 2 | 2 | 2 | 3 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 1 | 0 | 0 | 0 | 0 |
infraestruct. hidraulic | | 4 | 3 | 3 | 0 | 0 | 0 | 2 | 2 | 1 | 0 | 3 | 3 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
infraestruct. transport | | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 1.5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 2 | 1 |
urban | | 5 | 2 | 1 | 0 | 0.5 | 1 | 0 | 0 | 0 | 0 | 0.5 | 0 | 0 | 3 | 3 | 2 | 0 | 2 | 2 | 3 | 0 | 2 | 3 | 3 | 3 |
industrial | | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 2 | 3 | 0 | 2 | 2 | 2.5 | 0 | 0 | 3 | 2 | 2 |
buffer 1 o 5 km urban areas | 1 km | nº InhabitantS < 20.000 | 1.5 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 3 | 2 | 2 |
5 km | nº InhabitantS ≥ 20000 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 3 | 3 | 1 | 1 | 1 | 3 | 3 | 3 |
groundwater table 2008 | isolines purple color | <25 | 1 | 3 | 3 | 1 | 3 | 3 | 3 | 1 | 3 | 3 | 3 | 1 | 3 | 3 | 1 | 0 | 1 | 0 | 0 | 3 | 1 | 3 | 1 | 1 | 3 |
>25 to ≤ 50 | 2 | 2 | 2 | 1 | 1 | 2 | 1 | 1 | 1 | 2 | 3 | 1 | 2 | 2 | 3 | 1 | 1 | 1 | 1 | 0.5 | 1 | 2 | 1 | 1 | 2 |
>50 to ≤ 150 | 3 | 1 | 1 | 0 | 0 | 0.5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 3 | 1 | 3 | 2 | 0 | 0 | 0 | 1 | 1 | 2 |
>150 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 1 | 3 | 3 | 0 | 0 | 0 | 0 | 0 | 2 |
depth groundwatertable 2008 | isolines pink color | P >200 m | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 0 | 3 | 3 | 0 | 0 | 0 | 0 | 0 | 0 |
forestry masses. escale 1:50.000 | forests | | 3 | 1 | 1 | 2 | 1 | 1 | 3 | 3 | 1 | 1 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 3 |
hydrogeology units suitable to be recherged according toigme, 1991 | | | 3 | 2 | 2 | 1 | 1 | 1 | 2 | 2 | 1 | 1 | 2 | 1 | 1 | 2 | 1 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 1 | 1 |
areas distant up to 1 km from waste water treatment plants | buffer of 1 km and eq inhabitant data | <20.000 | 1 | 1 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 3 | 1 | 1 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
≥20000 to<200.000 | 2 | 1 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 3 | 3 | 1 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 2 |
≥200.000 | 3 | 2 | 2 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2 | 1 | 3 | 3 | 2 | 1 | 1 | 1 | 1 | 3 |
lagoon wwtp | buffer of 1 km | | 2 | 3 | 1 | 1 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
areas up to 5 km away from marine intrusion | buffer of 5 km ptos intrusion | 5 km | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 3 | 0 | 3 | 3 | 0 | 0 | 0 | 0 | 0 | 1 |
altitude range | masl | > 0 to <20 | 1 | 2 | 0 | 2 | 2 | 2 | 0 | 1 | 2 | 1 | 1 | 1 | 1 | 2 | 2 | 2 | 1 | 2 | 2 | 1 | 2 | 1 | 1 | 1 | 1 |
>20 to <1500 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 2 | 2 | 2 | 1 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 |
>1500 | 1 | 1 | 1 | 0.5 | 0.5 | 0 | 3 | 2 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 1 | 1 | 1 | 1 |
arid zones | precipitation | >400 mm | 3 | 2 | 1 | 0 | 2 | 2 | 2 | 1 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
≤400 mm | 1 | 1 | 0 | 0 | 0.5 | 0.5 | 3 | 0 | 0 | 0 | 3 | 2 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 0.5 | 3 | 2 | 2 | 1 | 1 |
meteo stations with watersurplus | sub-basins water surplus | | 2 | 2 | 1 | 1 | 2 | 2 | 2 | 2 | 2 | 1 | 1 | 2 | 1 | 3 | 1 | 1 | 2 | 1 | 1 | 2 | 2 | 1 | 2 | 2 | 3 |
distance to the coast | | < 2 km | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 3 | 1 | 1 | 1 | 1 |
> 2 to < 5 km | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 |
≥ 5 km | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 3 | 1 | 1 | 1 | 1 | 1 |
dunar systems(corine) | | | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 3 | 1 | 1 | 1 | 0 |
Figure 4.
Map of MAR areas and the most appropriate MAR devices. The “HydroGeoportal DINA-MAR” [
10] package also provides additional options for each zone.
Figure 4.
Map of MAR areas and the most appropriate MAR devices. The “HydroGeoportal DINA-MAR” [
10] package also provides additional options for each zone.
Figure 5.
“HydroGeoportal” predicting suitable areas to apply a MAR technique, notably in the Lower Guadalhorce aquifer (Malaga, Spain). The map displays the proposed location of MAR devices obtained through the exposed grades/weights system.
Figure 5.
“HydroGeoportal” predicting suitable areas to apply a MAR technique, notably in the Lower Guadalhorce aquifer (Malaga, Spain). The map displays the proposed location of MAR devices obtained through the exposed grades/weights system.
3.3. Economic Studies for MAR Activities Implementation Based on the Origin of the Water and Its Incorporation into “Hydrogeoportal” Map Viewer
An economic study was developed based on the investment ratio or the cost of the device in relation to the recovered water. The ratios for superficial MAR devices are approximately 1/5 of the ratio of the dams, whereas the ratio for ASR is similar to the dams ratio.
The referred study provides two alternatives for decision-making according to the origin of the sources of water, either of fluvial origin or sewage waters.
Table 4 shows the estimation process of the cost intervals. Column 3 differentiates six types according to either the origin of the water or the context in which each device is intended to be implemented. The five distinct classes are as follows: devices in river areas (wells, ponds and canals), dams and dikes in either surface or underground alluvial terrain, urban sustainable drainage systems, drilled wells less than 50 m deep and deep boreholes (deeper than 50 m).
The first alternative diverts running water from a river, channeling the water to an adequate aquifer (underground storage). This technique has several advantages including minimal occupation of the surface, less evaporation, preserved water quality, and the relatively low costs for the storage. For example, from the first row, using a river as a source of intake has a potential cost per action (investment ratio) of close to € 0.20/m
3 for an 8 km conduction pipe and the artificial recharge is performed using channels, infiltration ponds and wells. The cost for each activity is estimated to be close to 1.2 M€. Exploitation and maintenance costs have been estimated at € 0.01 m
3/year (real data taken from budgets of building projects performed by the company that the authors work for, in DINA-MAR, 2010 [
7]).
The other considered alternative is the direct injection of reclaimed water during managed aquifer recharge (files 5 and 6) using deep injection boreholes and wells. These injection sites are generally located in the vicinity of sewage treatment plants. The water must be tertiary treated, osmotized and inserted into the aquifers. The flow availability is more regular than in the previous alternative. This study considered flows between 50 and 80 l/s to be recharged through 50 m depth wells. Flows exceeding 100 l/s require boreholes approximately 500 m in depth (average values). This technique does not require special water surpluses and can be used for numerous purposes such as irrigation, combating marine intrusion, environmental practices, and industrial supply. The unit cost of investment is € 0.23/m3 (50 m) and € 0.58/m3 (500 m) (tertiary treatment was not considered). An average estimated cost for a 50 m building project is 172,500 €, and 580,000 € is estimated for a borehole 500 m depth plus additional MAR facilities. The estimated costs of conservation per year are € 0.13/m3 (50 m) and € 0.15/m3 (500 m).
The premises considered were the variability of the available flow (100 to 1000 l/s) and the possibility of applying this technique in approximately 16% of the Spanish territory (excluding the Canary Islands). This investigation also considered that the projects must be subject to concessions and require detailed suitability and feasibility studies.
The standards for water quality are ambitious in Spain; therefore, the costs may be lower for countries with less rigorous regulations.
Table 4.
The averaged economic index prior to connection with inventoried devices and “MAR zones” in the “HydroGeoportal DINA-MAR” iso-costs layer. The top numbers are specified in
Figure 2 (inventory). 1/0 indicates applies/not applies.
Table 4.
The averaged economic index prior to connection with inventoried devices and “MAR zones” in the “HydroGeoportal DINA-MAR” iso-costs layer. The top numbers are specified in Figure 2 (inventory). 1/0 indicates applies/not applies.
Mar techniques and devices | | | | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 |
---|
Dispersion | Channels | Wells | Filtration | Rain | Suds |
---|
| cases 1 | code | weight | infiltration ponds/wetlands | channels and infiltration ditches | ridges/ soil and aquifer treatment techniques | infiltration fields (flood and controlled spreading) | accidental recharge by irrigation return | reservoir dams and dams | permeable dams | levees | riverbed scarification | sub-surface/underground dams | drilled dams | qanats (underground gallerys) | open infiltration wells | deep wells and boreholes | boreholes | sinkholes, collapses | asr | astr | river bank filtration (rbf) | interdune filtration | underground irrigation | rainwater harvesting in unproductive | accidental recharge pipes and sewer system | sustainable urban drainage systems |
Economic index (average inversion) | euros/m3/year | fluvial | 0.20 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 |
river dams | 0.10 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
buried dikes in rivers | 0.22 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
suds (urban) | 0.08 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 0 |
wwtp <50 l/s | 0.23 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
wwtp >50 l/s | 0.58 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | |
Using the maps of potential “MAR Zones” for Managed Aquifer Recharge in Spain Iberian Peninsula and Balearic Islands (in [
8]) as the starting point, a new specific mapping is proposed using the total expected costs for each zone (€/m
3) that depended on the most appropriate device for each case. The result is a novel map (
Figure 6).
Figure 6.
(
a) Choroplethic map of “iso-costs” for the best MAR facilities in each “MAR Zone” for Spanish Peninsula and Balearic Islands; (
b) Detailed view for the East of Madrid province (square in
Figure 6a). These results are available at DINA-MAR [
8].
Figure 6.
(
a) Choroplethic map of “iso-costs” for the best MAR facilities in each “MAR Zone” for Spanish Peninsula and Balearic Islands; (
b) Detailed view for the East of Madrid province (square in
Figure 6a). These results are available at DINA-MAR [
8].
Classes:
- -
€ 0.08 /m3. Urban (SUDS) /forestry runoff capture;
- -
€ 0.10 /m3 Surface devices from river origin;
- -
€ 0.20 /m3 MAR from buried dikes in rivers;
- -
€ 0.23 /m3 Wells and boreholes with an injection capacity below 50 l/s;
- -
€ 0.58 /m3 Boreholes with an injection capacity exceeding 50 l/s.
This novel mapping provides valuable guidance for future development of MAR projects. Water managers and practitioners are anticipated to be able to utilize these innovative results.