Securing Flows in the River Systems through Irrigation Water Use Efﬁciency— A Case Study from Karula River in the Ganga River System

: The pressure on freshwater resources is leading to diminishing ﬂows in some of the critical river systems across the globe. India is no exception, and this is mainly because of water withdrawal for irrigation, which is often to the tune of 70% to 80% of the lean season ﬂows, with some proportion for domestic and industrial use. While graduating from the concept of environmental ﬂows and its assessment methodologies in India, the water-managers, the researchers and the conservationists are now moving towards answering the next question, if the rivers are to be revived, where will the water come from, especially in the case of over-allocated rivers, including the River Ganga. While the logical way is to look at the biggest user of water, i.e., irrigation, it remains to be seen whether the irrigation water savings will actually lead to enhancing ﬂows in a river, complementing the efforts towards maintaining e-ﬂows in rivers, or whether it will lead to more area under agriculture, bring changes in cropping patterns towards more water-intensive crops or result in something else. This is a growing debate across the globe, where India is no exception, and there has been a wide range of opinions in this regard. This paper discusses the process, ﬁndings and lessons from a joint initiative involving farmers, the Uttar Pradesh state Irrigation and Water Resources Department, Bijnor District Administration and a conservation organisation, WWF, to enhance ﬂows in a sub-tributary, called the Karula River, which is part of the Ganga River system. Another objective of this paper is to look at the scalability and replicability of similar approaches in other irrigation command areas to beneﬁt nearby river systems in general. Under this initiative, the team attempted to enhance ﬂows in the river Karula by routing the saved water from irrigation supplies in a canal commanded area. This saving of water is being achieved due to supply-side and demand-side measures that are being adopted in the project area. With the objective of ensuring the sustainability of the initiative, efforts are made to form an institutional arrangement, through which this initiative can be sustained beyond the project support.


Introduction and Context
Rivers, wetlands and aquifers are a critical source of water for nature, biodiversity and human beings. In fact, these sources have their own inter-dependent ecosystems. All of these ecosystems face multiple challenges, in the wake of: a.
feeding a growing population in a changing climate, while also conserving and restoring nature b.
reconciling multiple competing human demands for water, further compounded by changing lifestyles, market-driven processes and unplanned developmental activities

Project Area
Under the Karula river pilot project, the aspiration has been to enhance the diminishing flows in the Karula river, a tributary of the Ramganga River system (itself a tributary of the Ganga), from the saved water from the irrigated command area of a minor canal, called Khanpur Minor. The catchment area of Karula river is 957 km 2 , which is little over 4% of the catchment area of Ramganga basin (25,028 km 2 ). This canal system is operated and maintained by Uttar Pradesh Irrigation & Water Resources Department (UPI&WRD). The land use and land cover of Karula river catchment is agriculture dominated and the irrigated command area of Khanpur Minor canal is reflective of the same. The land-use and land-cover mapping for both Khanpur Minor command area and Karula River catchment is available as Appendices B and C.
The Karula River is not gauged, therefore the team started taking hydrological and hydraulic observations on fortnightly basis since mid of 2017 (with an objective to develop some understanding of flows in the river). The information on flows and hydraulic parameters were generated through these on-site observations (2017)(2018)(2019)(2020)(2021). This led to the understanding of the general flow's patterns and variations in water levels in the river across various seasons. Based on four years of data, the dependability curve was developed and the same is presented in Figure 1.
Ramganga water resources are stored in a reservoir called Kalagarh Dam, which is the second biggest dam-based reservoir (after Tehri dam) in the state of Uttarakhand, storing over 2448 million cubic meters of water, as per the National Register of Large Dams 2019, Central Water Commission [13]. The Kalagarh Multi-purpose Project was designed for irrigation, flood protection and production of electricity with an installed capacity of 198 MW (Uttarakhand Irrigation Department). The major proportion of water in Kalagarh dam is allocated to augment the lower Ganga Canal System (85%) while the rest is allocated to small independent canal systems known as the Ramganga sub feeder (10%) and Pheeka canal system (5%)-as per the information from authorities.
As a result of the diversion of Ramganga waters for irrigation canals, the flows in the Ramganga downstream barrage (Hareoli Barrage) are miniscule for the middle stretch of the Ramganga river. The lower stretch of the Ramganga, however, just before joining the Ganga, is relatively better due to contributions from the tributaries in the middle to lower stretches of the Ramganga River.
The Ramganga sub feeder canal system takes off from Kho Barrage built on the Kho River in Bijnor district (see Figure 2). This Ramganga sub feeder main canal has a series of minor canal systems extending irrigation supplies to the farms in three districts of Uttar Pradesh; one such minor canal is called the Khanpur Minor Canal, having a designed discharge of over 0.01 cubic m/s (3.5 cubic feet/second or 100 L/s). The irrigation command area of this canal system largely falls in four villages (Khanpur, Meerapur, Ramganga water resources are stored in a reservoir called Kalagarh Dam, which is the second biggest dam-based reservoir (after Tehri dam) in the state of Uttarakhand, storing over 2448 million cubic meters of water, as per the National Register of Large Dams 2019, Central Water Commission [13]. The Kalagarh Multi-purpose Project was designed for irrigation, flood protection and production of electricity with an installed capacity of 198 MW (Uttarakhand Irrigation Department). The major proportion of water in Kalagarh dam is allocated to augment the lower Ganga Canal System (85%) while the rest is allocated to small independent canal systems known as the Ramganga sub feeder (10%) and Pheeka canal system (5%)-as per the information from authorities.
As a result of the diversion of Ramganga waters for irrigation canals, the flows in the Ramganga downstream barrage (Hareoli Barrage) are miniscule for the middle stretch of the Ramganga river. The lower stretch of the Ramganga, however, just before joining the Ganga, is relatively better due to contributions from the tributaries in the middle to lower stretches of the Ramganga River.
The Ramganga sub feeder canal system takes off from Kho Barrage built on the Kho River in Bijnor district (see Figure 2). This Ramganga sub feeder main canal has a series of minor canal systems extending irrigation supplies to the farms in three districts of Uttar Pradesh; one such minor canal is called the Khanpur Minor Canal, having a designed discharge of over 0.01 cubic m/s (3.5 cubic feet/second or 100 L/s). The irrigation command area of this canal system largely falls in four villages (Khanpur, Meerapur, Rehtoli, Kolasagar) of Seohara Block in Bijnor district of Uttar Pradesh. Figure 2 illustrates the location of the pilot area on the map of the country.  The farmers in the catchment of the Karula river predominantly grow sugarcane, not only because of rich water resources and the presence of sugar-mills in the nearby areas (Seohara and Dhampur), but also due to the high economic value of sugarcane, as a cash crop, and the prevailing Minimum Support Price, which attracts farmers for assured incomes. According to a broad estimate, about 67% of the Khanpur Minor command area, i.e., about 260 ha, grows sugarcane and on the rest of the command, the usual wheatpaddy is grown. (Landuse Map, WWF-India-available as Appendix B) areas (Seohara and Dhampur), but also due to the high economic value of sugarcane, as a cash crop, and the prevailing Minimum Support Price, which attracts farmers for assured incomes. According to a broad estimate, about 67% of the Khanpur Minor command area, i.e., about 260 ha, grows sugarcane and on the rest of the command, the usual wheat-paddy is grown. (Landuse Map, WWF-India-available as Appendix B) The key statistics of the Khanpur Minor Canal are tabulated in Table 1. The tail end of the Khanpur Minor canal system is about 554 m (acceptable route) from the left bank of the river Karula. Therefore, one of the tasks under this initiative was to construct a passage to connect the tail-end of the canal with the left bank of the Karula river. This passage is a mix of open earthen and lined channel, with some portion as underground-pipeline.

Context and Approach
The idea of the Karula pilot has been conceived keeping in view a stakeholder-centric participative approach, wherein the farmers, concerned state government institutions (especially the Uttar Pradesh Irrigation and Water Resources Department) and district authority (Bijnor district) were key stakeholders. Whilst the project team led and coordinated the entire task, the stakeholders, local knowledge and wisdom played a critical role, in terms of contextual guidance, rapport building and farmer-level coordination.
A three-pronged approach was adopted to implement the pilot activities, including: Key amongst the above three aspects of the approach has been the inclusion of socioeconomic aspects, technical considerations, and stakeholder engagement. During implementation of the three-pronged approach, these aspects were not only taken into account, but were of central focus.
The Karula river initiative began with the assessment of baseline information pertaining to farmers, their landholdings, literacy rate, cropping cycle and cropping pattern, modes of irrigation, agricultural yield, input cost, profit margins, the status of canals and allied infrastructure, and more. With the increased understanding about the area, the work began, wherein the role of various stakeholders (including command farmers, Uttar Pradesh Irrigation and Water Resources Department (UPI & WRD), Bijnor District Administration and WWF India) was critical.

Stakeholders Engagement
Stakeholder engagement is seen as a means of contributing to improved water governance, where governance is defined as the policy and practices giving rise to particular forms of water management in different contexts (Wehn et al., 2018) [14]. Various stakeholders under the Karula initiative had played an inclusive and iterative part in realising the larger objective. Although their responsibilities were distinct with overlapping roles, they did appreciate each other's contribution and collaborated to work for the larger water conservation goal. For instance, the supply side-interventions (rehabilitation and maintenance) on the Khanpur Minor canal are a Uttar Pradesh Irrigation and Water Resources Department task, but farmers and other stakeholders played a critical role in the overall supervision and coordination.
On the other hand, a passage was required to be constructed to connect the canal's tailend with the riverbank, which was purely physical activity. Here, the technical guidance of the Uttar Pradesh Irrigation and Water Resources Department was obtained, yet the farmers played the key role, as they deliberated and finalised the alignment of the passage route. In this process, the involvement of district authorities was critical to provide information about the rights (based on revenue records) on the land between the passage routes. Only then could all stakeholders take the final call on the passage route and the work begin.
Social learning has been an added advantage of such stakeholder-centric approaches. One of the most salient aspects of social learning is the collective-rather than individualprocess of learning, knowledge co-creation and accumulation of wide experiences to generate a broader knowledge and evidence base, from which decisions can be taken (Wehn et al., 2018) [14]. In terms of the Karula initiative, it has been a mutual learning for all stakeholders. For instance, whilst the team promoted trench-based sugarcane farming in the Khanpur Minor canal command, farmers came up with the idea of multi-cropping by making use of moisture in the soil, and therefore growing other crops to maximise their economic gains. Some of the progressive farmers in the adjoining areas as well as the Department of Sugarcane, Government of Uttar Pradesh (Success Stories of Sugarcane development in District-Bijnor, Uttar Pradesh, 2018 [15]) were promoting these practices. As a result of knowledge exchange, exposure visits and personal initiatives, many farmers adopted this idea. This has also been a learning experience for their fellow farmers (even outside the command area).
The chronology of the stakeholders' engagement process is illustrated in Figure 3.
partment of Sugarcane, Government of Uttar Pradesh (Success Stories of Sugarcane development in District-Bijnor, Uttar Pradesh, 2018 [15]) were promoting these practices. As a result of knowledge exchange, exposure visits and personal initiatives, many farmers adopted this idea. This has also been a learning experience for their fellow farmers (even outside the command area). The chronology of the stakeholders' engagement process is illustrated in Figure 3.

Role of Different Stakeholders across the Three-Pronged Approach
The engagement of various stakeholders, in a categorised (activity-based) manner is explained in Table 2 along with their specific roles, the challenges that were faced and how these challenges were overcome.
Whilst the demand-side and supply-side interventions were implemented side-byside, however there is a degree of complementarity due to which both these aspects proved to be supportive to the Karula River initiative. A step-by-step process chart illustrating the implementation of activities under both types of interventions is available as Appendix D.

Farmer Surveys-Approach and Methodology
With an objective to assess the impact of the Karula river initiative on the farmers with respect to (i) on-farm water management and water savings and (ii) agricultural productivity and economic value of produce per unit of area, a detailed questionnaire (Appendix E) was developed. Based on this questionnaire, twelve farmer surveys were conducted jointly by some of the authors between 2018-2019 (sugarcane cropping season). For these farmer surveys, the sample selection was done from all the three reaches of Khanpur Minor canal, i.e., 2 farmers from each of the canal reach, i.e., head, middle and tail. The identification of the head, middle and tail end of the canal is done by dividing the total length of the canal into three equal parts. Within the reach the selection of farmer for survey was random. The farms where intervention (having BMPs) was made were noted as 'Demonstration-farms' and the ones with usual agricultural practices (without BMPs) were named as 'Control-farms'. It was noted while selecting the control farm, that both the control and demonstration farms belonged to similar specifications, except for sowing methods (with trencher and without trencher). Along with the field visit to all farms, detailed interactions based on the agreed questionnaire were conducted. Among all the command area farms, six sample demo plots (two each from head, middle and tail reaches of the canal) and correspondingly six control plots were selected to assess the impact and benefits of these interventions. Both the demonstration farms and control farms were geo-tagged, and their locations can be seen on the canal command area in Appendix F.
The farmer surveys were conducted through a combined approach, i.e., field-level measurements and 'farmer recall' method, this echo similar approach noted by Barton and Taron 2010 [16], while conducting representative farm surveys in the irrigation command areas in Tungabhadra River Basin, India.
There is a body of literature that talks about farmer-recall method as one of the means for conducting irrigation and agricultural surveys, especially in the absence of precise measuring and monitoring support. The analysis by Beegle et al., 2011 [17], as part of the work in three African countries, shows little evidence of recall bias impacting agriculture data quality at farm-level. They noted that the results of their work allay some concerns about the quality of some types of agricultural data collected through recall over lengthy periods. On the other hand, Wollburg et al., 2020 [18] find that, the recall length has a significant impact on reported outcomes in all areas of interest in agriculture surveys and analysis. They therefore suggested that, to reduce the risk of recall error and to improve the quality of key variables in agricultural surveys, shorter recall periods can be one of the solutions.
The authors, therefore, collected the information from the farmers during different stages of sugarcane crop, i.e., during land preparation, sowing, input applications and harvesting. Whilst multiple visits and interactions could be resource and time intensive; but, since the Karula river initiative has been a 4-year one and the team happened to visit field numerous times, which made it possible for the team to visit the farms and have discussions with the farmers during different phases of the crop cycle. This aspect is in alignment with the suggestions made in previous studies and research (Wollburg et al., 2021 [18], Beegle et al., 2011 [17], Barton and Taron 2010 [16]). Besides the farmer surveys, for the purpose of validation of information related to water application at sample farms, the team also measured the discharge and water levels in the field channels and farms.
The hydrological observations at Khanpur Minor were carried out through monitoring of gauge levels, active channel width and velocity to calculate discharges, which were used for water accounting. The observed discharge data is not available for the Karula river, as there is no monitoring station on this small river. It therefore becomes imperative to establish baselines which could later be utilised for comparison with the volume of saved water from irrigation discharged in the Karula river to improve its health.
The water used for sugarcane irrigation, both in demo and control fields, was compared with its ideal (theoretical) requirement. The actual discharge from tube wells with a 4-inch delivery pipe to the irrigation channel was measured at the site, using area velocity method and volumetric measurement. On this basis, an average discharge of 0.014 cubic meter/second (40 litres per second) was adopted. A primary survey was conducted to gather information regarding the actual running time of tube-wells in demo and control plots for each irrigation/season. The volume of water applied in a field was calculated by multiplying the discharge with water application time. The irrigation water depth applied to a plot was calculated by dividing the total volume of water applied by the area of the plot. The ideal (theoretical) crop water requirement is as per FAO (Food and Agriculture Organization) norms using CROPWAT-a tool for calculating crop water requirements. The meteorological data of the nearest climatological station (Bareilly) was used. The rainfall data of the district Bijnor was taken, and the value of crop coefficient "Kc" was taken from guidelines issued by CWC (Central Water Commission, Government of India) in 1984 (Technical Series 2: A Guide for Estimating Irrigation Water Requirement, Ministry of Irrigation, Water Management Division, New Delhi, May 1984 [19]. The theoretical irrigation water depth for sugarcane crop computed using FAO's CROPWAT Program is calculated as 67.6 cm, including the 25% leaching requirement. Against this norm, the current irrigation water depth in control plots (without trench method) was calculated as 87.6 cm. The irrigation water depth in demo plots (with trench method) was calculated as 72.3 cm.

Institutional Strengthening
The state of Uttar Pradesh promulgated the Uttar Pradesh Participatory Irrigation Management Act in the year 2009 and since then the constitution of Water Users Associations (WUAs) at canal systems has been underway in a phased manner. So far, this work has been done in project areas of the Uttar Pradesh Water Sector Restructuring Project (funded by the World Bank). Hence, WUA formation in this area (Khanpur Minor, around the Karula river) had not begun. Under the Karula initiative, WUA was considered as an appropriate participatory institutional mechanism to sustain and take forward this initiative.
Work towards formation of WUA in the Khanpur Minor command area has been underway since 2018, with a series of awareness, sensitization and training programmes being conducted to build the capacity of farmers regarding WUA functioning, and its roles and responsibilities as per the Uttar Pradesh Participatory Irrigation Management Act, 2009 (UP PIM Act 2009). Exposure trips of farmers from Khanpur minor command area to successful WUAs in the state and outside the state have also been conducted. This way, a strong momentum was generated in favour of constituting the WUA and a critical mass of experts and vigilant farmers was readied to support the affairs of the WUA. Finally, in February 2021, the Khanpur Minor WUA was constituted with the unanimous election of its governing board members. The Khanpur Minor WUA was constituted following the provisions of the UP PIM Act 2009. The unanimous election results indicated the overall positivity amongst the command farmers towards the initiative as well as the institutional setup.

Results
This section discusses the findings of a sample survey of farms at all reaches of the Khanpur Minor canal, i.e., head, middle and tail reaches of the canal. Farmers from both typologies of farms, i.e., where interventions are being carried out, and where agriculture is still being practised in a traditional manner, were interviewed. The data from these interviews were analysed and the results are presented in this section.
This section essentially narrates the following: 1.
Water savings at farm level 2.
Flows restored in the Karula river 3.
Change in sugarcane productivity 4.
Economic implications for the farmers and crop-water productivity

Water Savings at Farm Level
The sugarcane crop raised using traditional practices (primarily, flood irrigation) consumed more water, whereas the crop raised using Better Management Practices (BMPs), including trench-based technique, consumed less water. The analysis of data shows average water savings to the tune of 17.4% using the trench method of sowing, (with the range between 40% and 10%) as shown in Figure 4. The saving of water can be attributed to the larger spacing among cane rows in the trench method.
is still being practised in a traditional manner, were interviewed. The data from these interviews were analysed and the results are presented in this section.
This section essentially narrates the following: 1. Water savings at farm level 2. Flows restored in the Karula river 3. Change in sugarcane productivity 4. Economic implications for the farmers and crop-water productivity

Water Savings at Farm Level
The sugarcane crop raised using traditional practices (primarily, flood irrigation) consumed more water, whereas the crop raised using Better Management Practices (BMPs), including trench-based technique, consumed less water. The analysis of data shows average water savings to the tune of 17.4% using the trench method of sowing, (with the range between 40% and 10%) as shown in Figure 4. The saving of water can be attributed to the larger spacing among cane rows in the trench method.

Flows Restored into the Karula River
Now, after the rehabilitation, the irrigation system is fully functional whenever the Khanpur Minor Canal gets water as per the roster (which is the mechanism of irrigation scheduling, that defines the date and time of water distribution for various canals within a system, in a turn-by-turn fashion) issued by the UPI & WRD. The canal system is run as per the roster. The saved water from the canal is now released into the Karula river through the passage. The Khanpur Minor Canal generally runs for 6-8 months in a year (depending upon water availability in the reservoir and irrigation water demand by the command farmers).

Flows Restored into the Karula River
Now, after the rehabilitation, the irrigation system is fully functional whenever the Khanpur Minor Canal gets water as per the roster (which is the mechanism of irrigation scheduling, that defines the date and time of water distribution for various canals within a system, in a turn-by-turn fashion) issued by the UPI & WRD. The canal system is run as per the roster. The saved water from the canal is now released into the Karula river through the passage. The Khanpur Minor Canal generally runs for 6-8 months in a year (depending upon water availability in the reservoir and irrigation water demand by the command farmers). From May 2019 until June 2021, the Khanpur Minor canal, through the passage, discharged a total of 62.55 million litres of water saved from irrigation to the Karula river across 67 days from May 2019 to June 2021. The discharge from the tail end of the Khanpur canal into the Karula river within this period ranged from 0.0033-0.022 cumec (3.4-22.6 litres per second), with an average flow rate of 0.011 cumec (11.9 litres per second), which is 11% of the 'designed discharge' of Khanpur Minor canal. Figure 5 shows the temporal variation in saved water discharged into the Karula river since May 2019. Figure 6 gives an idea of minimum flows in Karula River and average discharge in Khanpur Minor vis-à-vis number of days in respective months, the saved water flown into the river.
From Figure 1, which shows the flow duration curve, it can be inferred that, at 90% dependability (leanest flows), about 0.085 cubic meter/second (85 L/s) water is available, whereas minimum average flows of 0.10 cumec (102 L/s) are observed in the month of June in the Karula, near the tail end of the Khanpur canal. It is also evident here that the saved water from irrigation discharged into the river Karula accounts for 7% of minimum lean season flows. It can be seen that except during the monsoon months (June to October) saved water from irrigation is discharged into river Karula during all the lean season months. With further adoption of Better Management Practices in the remaining sugarcane area in command and the scaling up of trench-based interventions, it is expected that more water will be contributed by the Khanpur command to the Karula River.
Water 2022, 14, x FOR PEER REVIEW 15 of 33 second), which is 11% of the 'designed discharge' of Khanpur Minor canal. Figure 5 shows the temporal variation in saved water discharged into the Karula river since May 2019.   From Figure 1, which shows the flow duration curve, it can be inferred that, at 90% dependability (leanest flows), about 0.085 cubic meter/second (85 L/s) water is available, whereas minimum average flows of 0.10 cumec (102 L/s) are observed in the month of June in the Karula, near the tail end of the Khanpur canal. It is also evident here that the saved water from irrigation discharged into the river Karula accounts for 7% of minimum lean season flows. It can be seen that except during the monsoon months (June to October)   second), which is 11% of the 'designed discharge' of Khanpur Minor canal. Figure 5 shows the temporal variation in saved water discharged into the Karula river since May 2019.   From Figure 1, which shows the flow duration curve, it can be inferred that, at 90% dependability (leanest flows), about 0.085 cubic meter/second (85 L/s) water is available, whereas minimum average flows of 0.10 cumec (102 L/s) are observed in the month of June in the Karula, near the tail end of the Khanpur canal. It is also evident here that the saved water from irrigation discharged into the river Karula accounts for 7% of minimum lean season flows. It can be seen that except during the monsoon months (June to October)

Changes in Sugarcane Productivity
The data around sugarcane yield per unit area was discussed with the farmers. The figures around changes in yield (reported by the farmers) vary, depending upon the level/degree of adoption/adherence to Better Management Practices suggested, in addition to the adoption of the trench-based practice by individual farmers. Therefore, there may be some variations in the outcome or productivity levels.
In this case, of the six farms sampled, the general average trend of agricultural productivity enhancement is about 23.8%, with the range between 34% and 19%; Figure 7 exhibits the degree of change in sugarcane productivity.
figures around changes in yield (reported by the farmers) vary, depending upon the level/degree of adoption/adherence to Better Management Practices suggested, in addition to the adoption of the trench-based practice by individual farmers. Therefore, there may be some variations in the outcome or productivity levels.
In this case, of the six farms sampled, the general average trend of agricultural productivity enhancement is about 23.8%, with the range between 34% and 19%; Figure 7 exhibits the degree of change in sugarcane productivity.

Economic Implications for Farmers and Crop-Water Productivity
Farmers have benefited in terms of earnings as well. The average income per unit hactare area, in comparison with control plot, is to the tune of Rs. 117,000/ha, whereas the range is Rs. 162,039/ha to Rs. 91,884/ha (Figure 8).

Economic Implications for Farmers and Crop-Water Productivity
Farmers have benefited in terms of earnings as well. The average income per unit hactare area, in comparison with control plot, is to the tune of Rs. 117,000/ha, whereas the range is Rs. 162,039/ha to Rs. 91,884/ha (Figure 8).  Income per unit of water consumed (irrigation applied) was enhanced by 117 % (on average) in farms using BMPs than a traditionally sown farm (Figure 9). A farmer, on average, gets an additional income of Rs. 20.60 on every cubic metre of irrigation water used in the trench method. This is mainly due to a reduction in input costs (less fertiliser/pesticide, fuel etc.) and an increase in yield and higher returns.   Income per unit of water consumed (irrigation applied) was enhanced by 117 % (on average) in farms using BMPs than a traditionally sown farm (Figure 9). A farmer, on average, gets an additional income of Rs. 20.60 on every cubic metre of irrigation water used in the trench method. This is mainly due to a reduction in input costs (less fertiliser/pesticide, fuel etc.) and an increase in yield and higher returns. Income per unit of water consumed (irrigation applied) was enhanced by 117 % (on average) in farms using BMPs than a traditionally sown farm (Figure 9). A farmer, on average, gets an additional income of Rs. 20.60 on every cubic metre of irrigation water used in the trench method. This is mainly due to a reduction in input costs (less fertiliser/pesticide, fuel etc.) and an increase in yield and higher returns. The productivity per unit area may be attributed to the spacing between rows, which allows better aeration and provides space to grow freely, which results in cane plants of larger circumference and height, and weighing more, with greater sugar content. The per   The productivity per unit area may be attributed to the spacing between rows, which allows better aeration and provides space to grow freely, which results in cane plants of larger circumference and height, and weighing more, with greater sugar content. The per unit less water consumption may also be attributed to the heavier cane, providing greater yield of more value-with less water used.
Besides changes in sugarcane productivity and saving in irrigation water, the trench method offers opportunities to the farmers to grow a second crop in the sugarcane fields, simultaneously, between the ridges. Most of the farmers grow mustard or black-gram (urad) as an additional crop. These crops are not provided additional irrigation as their less water requirement is easily met with the soil moisture regime of the sugarcane crop. Farmers can use the additional crop for their consumption as well as to gain extra income from it. It has been calculated from demo farm data that the average income of multi-cropped sugarcane fields is around 20% higher (with the range between 15% and about 26%) than the single sugarcane crop sown with Better Management Practices, including the trench method, as shown in Figure 10.
The secondary crop, on average, contributes to around 17% (with the range between 13% and about 20%) of the total income of trench method sugarcane cultivation with multi-cropping. (Figure 11).
If the secondary crops had been sown alone, it would have consumed 15 cm irrigation water depth per hectare (assuming 50% area covered in sugarcane field is by the secondary crops, which consumes 30 cm water for maturity). This is totally saved by the irrigation water provided to the sugarcane. The total water requirement of both crops, if each crop is sown alone, comes to 87 cm (72cm + 15cm). Thus, the saving of 15 cm water of 87 cm is 17.2%. The sugarcane crop raised using trencher tool already has a saving of 17.4% over traditional sowing, hence the multi-cropping scenario offers total water saving of 34.6% over the traditional raising of sugarcane crop.
(urad) as an additional crop. These crops are not provided additional irrigation as their less water requirement is easily met with the soil moisture regime of the sugarcane crop. Farmers can use the additional crop for their consumption as well as to gain extra income from it. It has been calculated from demo farm data that the average income of multicropped sugarcane fields is around 20% higher (with the range between 15% and about 26%) than the single sugarcane crop sown with Better Management Practices, including the trench method, as shown in Figure 10. The secondary crop, on average, contributes to around 17% (with the range between 13% and about 20%) of the total income of trench method sugarcane cultivation with multi-cropping. (Figure 11). If the secondary crops had been sown alone, it would have consumed 15 cm irrigation water depth per hectare (assuming 50% area covered in sugarcane field is by the secondary crops, which consumes 30 cm water for maturity). This is totally saved by the  Farmers can use the additional crop for their consumption as well as to gain extra income from it. It has been calculated from demo farm data that the average income of multicropped sugarcane fields is around 20% higher (with the range between 15% and about 26%) than the single sugarcane crop sown with Better Management Practices, including the trench method, as shown in Figure 10. The secondary crop, on average, contributes to around 17% (with the range between 13% and about 20%) of the total income of trench method sugarcane cultivation with multi-cropping. (Figure 11). If the secondary crops had been sown alone, it would have consumed 15 cm irrigation water depth per hectare (assuming 50% area covered in sugarcane field is by the secondary crops, which consumes 30 cm water for maturity). This is totally saved by the From the river conservation and water management perspective, the major outcome and impact of this initiative is the water savings from irrigation and release of that water into the river Karula through the passage. There are two sets of calculations-total water savings at farm level in view of using Better Management Practices (BMPs), including trench-based sugarcane farming, and actual water discharge data (from the gauge near the riverbank on the passage). These calculations are shown in Table 3. Water saved to the tune of 62,550 cubic metres (25% of potential water savings) has found its way into the Karula river, thereby enhancing its flows. There are substantial conveyance (seepage) losses and unaccounted withdrawals, which has significantly reduced the overall volume of actual water released into Karula river. However, this means that there is an opportunity to bridge this inefficiency gap, so that the net gains can be enhanced.

Discussion
Globally, there are several initiatives, through which environmental gains are being tried and tested while implementing irrigation water use efficiency. Various researchers, over the period of time, have reviewed these initiatives. Qureshi et al., 2010 [20] reviewed two key incentive policies to acquire water for e-flows for a part of the Murray-Darling Basin (MDB) in Australia. One policy consists of paying irrigators and water delivery firms to make capital and management investments that improve on farm irrigation and water-conveyance; the other policy consists of having the government buy water from irrigators on the active MDB water market. The result from their study shows that, the first option leads to relatively larger return flows reductionwhich is not a welcome outcome. On the other hand, the second option tends to induce significant irrigated land retirement with relatively large reductions in consumptive use and small reductions in return flow. Thus, making the second option more viable than the first one.
Koech R. and Langat P. 2018 [21] reviewed the advancements made towards improving irrigation water use efficiency (WUE), with a focus on irrigation in Australia but with some examples from other countries. This body of work has demonstrated that the adoption of water-efficient technologies has delivered water savings at the field scale, with some of the savings being released as e-flows. However, the net water saving at the basin scale is not always achievable. In fact, some studies have demonstrated that a net increase in water consumption, largely due to the reuse of the saved water leads to expansion of land under irrigation.
On the other hand, a study by Ward and Velazquez 2008 [22] from Rio Grande basin, found out that water conservation subsidies are unlikely to reduce water depletions by agriculture. This study suggested that accurate accounting and measurement of water use can help identify opportunities for water savings, increase water productivity, and improve the rationale for water allocation among uses. Other measures include reducing or converting nonbeneficial evaporation from soil to beneficial crop ET, restricting acreage or water use expansion in cropped areas, switching to lower water-consuming crops, or irrigating current crops at a deficit.
Koech R. and Langat P. 2018 [21] further concluded that an overall reduction of water consumption at the basin scale is likely to be achieved when water-efficient technologies are used in combination with other measures, such as provision of incentives for water conservation and regulations to limit water allocation.
Unlike some of the global contexts, the water markets and subsidies for 'high-end' canal modernization, which comprise of pipelines, precision irrigation, linings etc. are not in practice at the moment in the catchment of Karula river; therefore, the basic improvisations in irrigation and agricultural practices holds the key to secure water for environmental requirements. This has been the thought process behind the propositions that were made to the farmers in the beginning of Karula pilot.
The Karula pilot was envisaged as a unique context-specific initiative, but under the backdrop of a well-debated idea-whether efficient irrigation water use can actually aid flows enhancement into the rivers and ultimately support the maintenance of e-flows in the rivers. On the other hand, there were externalities, which had the potential to disrupt the aspired outcomes of this initiative. However, a carefully developed stakeholder-led initiative has begun to deliver on the stated objectives, i.e., enhancing the flows in the river Karula. Herein, there have been favourable changes in terms of water use requirement from the demand-side and an efficient irrigation canal system, which ensured reliable water supply to the farmers. This has led to the achievement of saving water meant for irrigation and its release into the Karula river, besides benefiting the farmers economically. It is a combination of both these aspects along with institutional building, that powered the Karula pilot.
The specific values of water released into the river Karula would remain a dynamic figure, as there are several associated and external factors that would influence this. Some of these key factors could be as follows: a.
The quantum of water flows in the Khanpur Minor canal, which may vary depending upon Availability of water in the main/parent canal Irrigation demand by farmers within the Khanpur command area Unauthorised withdrawals from the Khanpur Minor canal b.
State of maintenance of Khanpur Minor c.
Rainfall in the local catchment d.
Maintenance of passage structure To sustain such an effort beyond the project duration is indeed a challenging ask, as there would be an apprehension that the situation would be back to business-as-usual once the external support is withdrawn. To overcome this challenge, the formation of the Water Users Association (WUA) as per the provision of the Uttar Pradesh Participatory Irrigation Management Act 2009 was facilitated. In February 2021, the Khanpur Minor WUA was constituted and the elections for Executive/Governing Body (comprising of President, Secretary, Treasurer and other office bearers) of the WUA were unanimous. This is indicative of positivity amongst command farmers about the institutional support for this initiative, besides bringing them permanent solutions to the operation and maintenance of the Khanpur Minor canal system.
Parallel to the efforts to form the WUA at the Khanpur Minor level, the capacity building of the farmers about roles, responsibilities and functions of WUA was done through training programmes, exposure visits to successful WUAs in the state and at the national level. This has helped in mobilising a "critical-mass", who is now ready to take up the affairs of the WUA. However, the WUA is only recently established and further support will be needed for it to become fully sustainable in financial and institutional terms.
The Karula initiative was planned in such a way that the process for enhancement of flows in the Karula river fits within the current mechanism of irrigation scheduling and allocations and does not overwhelmingly change existing farm practices. This would mean that the envisaged objective is likely to achieve partial success in terms of actually maintaining the e-flows for a river. Therefore, the initiative may not by itself achieve the full suite of e-flows requirements (locations, timing and quantity of flows) for the Karula river, but it certainly aids to enhance the flows in the river in times of need, like the lean season of November to June.
Some local factors that worked in favour of the Karula pilot were as follows: a. Farmers in this area largely grow sugarcane (a water intensive crop) and the produce is insured by the Central and State government through Fair and Remunerative Price (FRP) and State Advised Price (SAP). Additionally, according to Niti Aayog (serves as the apex public policy think tank of the Government of India), the sugar mills that buy sugarcane are mandated to purchase crops from farmers within a specified radius known as the Cane Reservation Area at the FRP, which serves as defined market linkage for this cash crop. The team was fully aware of this fact-due to the availability of water and assured purchase of produce by the government through sugar mills, farmers would not switch to another water-intensive crop, which is a general apprehension otherwise. b.
There has been another concern that farmers may tend to increase areas under agriculture using water saved from the application of Better Management Practices (including trench use) in sugarcane farming. Nevertheless, the team still faced a situation where, since the Khanpur Minor canal did not feed all the farms in the middle to tail-end, saturation of the command area was bound to happen -once the demand-side and supply-side interventions were applied in the command area, the saved water in the head to middle reaches of the canal would be used by the tail-enders. As this was well-understood since inception and there was no hurried and strict response from the team to ensure that the saved water fed immediately into the river, the team worked with the tail-end farmers and assured them that they could use the water from the canal as well as from the passage for irrigation (by adopting trench-based technique), while letting the remaining water discharge into the river. The tail-end farmers agreed, and this strategy worked well. c.
The other consideration in the Karula pilot is the promotion of local and scalable ideas to manage the demand-side aspect and not really call for hi-tech, expensive means of pressure irrigation (drip and sprinkler), at least in the early phases of the project. The idea was not to introduce something totally new to the area, but to bring some of the improvisations that are rare but known amongst the progressive farmers in and around that district. However, at a later stage, a few farmers proposed the idea of demonstrating pressure irrigation techniques and the team agreed to facilitate these.
Various scientific studies have suggested that water from seepage through unlined canals recharges groundwater (Mirudhula K. 2014) [23] and helps build shallow aquifers that are generally used as a source for irrigation. Infiltration from the canals recharges the aquifer directly and partially compensates for water uptake from plants and evaporation (Arumi J.L. et al., 2009) [24]. The idea behind this project was to support conjunctive use and reduce overall water withdrawal (canal and groundwater for irrigation), combined with improved practices in irrigation and agriculture, which is likely to reduce the losses from evapotranspiration, a matter of further investigation.
The groundwater serves the function of discharging base-flows into the river, especially during lean season. It was observed that excess infiltration from the flood irrigation technique (earlier prevalent in the command area), though, may be recharging shallow aquifers to some extent, but would also be increasing the overall evapotranspiration (ET) losses. Post field interventions, the volume of canal water applied has reduced, which may affect infiltration, but will also reduce the overall groundwater abstractions, subsequently helping in stabilising groundwater levels in the long run and will continue to feed the river through base-flows. Following the interventions in the Khanpur Minor command area to reduce abstractions, increase efficiency, and connect the canal tail to the river, the water has a more direct route to the river which augments riverine flows in its leanest flows periods. However, there are larger river-groundwater interactions in play too, which impact the riverine baseflows. Precise and conclusive information in regard to the exact benefits to the river and to the catchment will need to be inferred through long-term hydrological and hydro-geological monitoring.
Initiatives like the Karula river pilot can influence larger irrigation systems, as in a general scenario, the tail-ends of irrigation canals (in gravity-based systems) are close to rivers and wetlands. The saved water from irrigation, if conveyed to these freshwater resources, is likely to aid improvement of flows in the rivers. Arriving at such a stage is a critical milestone for maintaining e-flows in a river, because the most important question for e-flows maintenance is where the water for e-flows will come from, especially in over-allocated river basins. The irrigation water use efficiency initiative, as that of Khanpur Minor, could theoretically be upscaled at the extent of the Karula basin-about 65% (625 sq. km.) of catchment area of the Karula river grows sugarcane (as depicted in Appendix B). The extrapolations show that there is a potential of saving about 68 million cubic metres of water from about 70% of sugarcane farms within the Karula catchment. Whilst all the sugarcane farms in the Karula catchment may not be supported by surfaceirrigation facilities (that could have otherwise directly demonstrated enhancing flows in Karula); however, potentially lesser groundwater pumping in view of application of Better Management Practices would certainly benefit the aquifer and river from these savings. This is likely to contribute to river discharges through enhanced base-flows. Moreover, there are about 30 minor irrigation canals in the adjoining areas of Khanpur Minor and these are all fed by the Ramganga Canal. If this initiative could be up-scaled in these irrigation sub-systems, then more water could be augmented into the Karula river.
Whilst the apprehension may be valid that even if the water from irrigation is saved, it may lead to "enhancing-area-under-irrigation' and/or push for 'adoption-of-more-waterintensive-crops", in certain circumstances, the Karula initiative has proved that a carefully designed participative programme can actually bear desired results in terms of enhanced flows. These are complex questions and the same are being debated by various researchers. Globally, many countries and regions are trying to address and overcome similar challenges. For instance, the European Union (EU) as part of its agri-environment measures (AEMs) 2017 [25] provide financial support for Member States to design and implement programmes and projects. AEMs are developed under the EU's Member State's Rural Development Programme. They are mandatory for national and regional administrations, but voluntary for farmers. Farmers who choose to go beyond the current basic requirements can claim payments for AEM. Each measure has to have a specific environmental objective, such as-the protection or enhancement of biodiversity, soil, water, landscape, or air quality, or climate change mitigation or adaptation. Approximately 25% of the EU's utilised agricultural area is under AES contracts with farmers, including organic farming.
With the passage of the Water Act 2007, the Murray-Darling Basin (MDB) in Australia is in the process of major policy reform. This reform process is multifaceted and is expected to be completed by 2024. Key aspects of the reforms include: (i) the setting of sustainable diversion limits (SDLs) that will determine the average annual levels of extractions of water from surface and groundwater at a basin and catchment scale; (ii) the purchase, until 2015 of water rights in the form of water access entitlements for environmental purposes; and (iii) the on-going use of subsidies for water infrastructure to increase both on-farm and off-farm water-use efficiency. The progress of this ambitious and complex programme has been reviewed by many researchers (including-Grafton and Wheeler 2018 [26], Williams et al., 2019 [27]). While reviewing the possible effects of water recovery on river flows in MDB, Williams et al., 2019 [27] emphasized, the critical need to comprehensively measure the effects on recoverable return flows of increased irrigation efficiency, as a result of water infrastructure subsidies. It was further advocated by them that, good public policy requires a halt to any further water infrastructure subsidies in the Murray-Darling Basin to increase irrigation efficiency until it can be scientifically determined by how much, if at all, whether such infrastructure subsidies increase net stream and river flows, and at what cost. While commenting on similar aspects, Grafton and Wheeler 2018 [26] pointed out that, buy-back is a cost-effective measure in comparison to subsidies.
Whilst these large scale reforms are underway with varying complexities, smaller initiatives like this one on Karula River have the potential to provide some helpful pointers to advance or broadbase the outcomes of such reforms. On the other hand, the Karula initiative demonstrates an alternative to promoting radical changes (suggesting newer cropping patterns or promoting pressure-irrigation in the early stages) in a short time span, without much rapport building with the stakeholders. It would be much more prudent to look for local solutions (trench-based sugarcane farming, other package of practices including application of bio-pesticides and bio-fertilizers) and promote them in the project area. Once the benefits for the farmers are proven, they will come forward to support other forthcoming propositions as well.

Practical Implications of Karula River Initiative
The Karula River initiative provides some insights on how relatively straightforward and inexpensive interventions, co-designed with farmers and other stakeholders, can support achievement of environmental and socio-economic objectives in contexts similar to that found in the Karula River. Some of the key elements and takeaway points from the Karula River initiative are: a.
The objective of irrigation water saving was to enhance the flows in the river, besides reducing the chemical inputs and increasing the agricultural productivity and therefore farm income. b.
No high-end irrigation techniques (like drip, sprinkler) were considered across the project phase and mere improvisations in existing irrigation practices were promoted and implemented. c.
No absolute and radical canal modernization (concrete/brick-lining of the canals, pipelines etc.) was done and mere basic canal rehabilitation was undertaken. d.
Basic water management, water depth and water discharge monitoring mechanisms were considered (physical gauges with calibrated sections, flow-meters) instead of sophisticated tools and equipment. e.
Promotion of unified approach as an institution, i.e., Water Users Association, rather than a fragmented one, i.e., at individual farmer-level.
These points can be some of the critical insights for similar initiatives in other river basins. It is proposed that a gradual, inclusive, multistakeholder-led process hold the key to the success of the work.

Conclusions
As lessons learned from the Karula initiative, the following takeaway points are therefore made, which may not be conclusive for further replication of similar ideas, but are certainly key pointers for future considerations: a.
Integrated approach: rather than merely looking at a single aspect, a holistic and comprehensive view works better. For instance, instead of simply working on demand-side aspects, both supply-side aspects and institutional strengthening were also taken-up and this helped to achieve the objective. In addition, engagement with all key stakeholders, including the irrigation department, district authorities, local agriculture science centres and farmers, was critical for a transformational change b.
Equity and Ownership: a saturation of canal commanded area, in terms of access to irrigation water across the various ends of the canal (head-middle-tail) is a necessary and critical step in such exercises and therefore this should be acknowledged to get wholehearted support from the farmers across all reaches within the canal system. Such considerations also allow better buy-in and sense of ownership amongst the farmers in the entire canal command area c.
Monitoring: the monitoring of the transformation is a critical aspect and if this is done in a joint fashion, it adds value not only for the initiative, but also better informs the stakeholders about the change that is in the offing d.
Scalability: considering a unit for proof-of-concept that is scalable, is critical, as the demonstration at an optimum unit has far better potential of upscaling, and therefore mainstreaming Going forward, the team is now aspiring to upscale this initiative to about 16,000 hectare of Culturable Command Area (CCA) in the state of Uttar Pradesh, where the Ganga water resources feed the irrigation canals. This three-year programme will explore new leads, ideas, challenges, and opportunities, which would be worth narrating to a wider audience for their information, understanding and uptake.
It is fully recognized that the rejuvenation of some of the world's most populated and contested river systems continues to remain a challenging task, if the tributaries, rivulets, and wetlands in such river basins are not considered. It is in this context that the Karula pilot initiative is a pointer for policymakers and water-managers for the future. It is hoped that initiatives of this sort will help in curbing water-scarcity and will ensure wiser use of this precious resource. Moreover, the overall local ecology is set to benefit in this process as well.
Author Contributions: N.K., S.B., A.M., R.B., P.K.S. and R.K.A. were core members of the implementation team for Karula River initiative; N.K. conceived the idea of the paper and prepared first draft of the paper, plus subsequent revisions to the paper.; S.B. provided valuable guidance and inputs throughout the paper drafting; A.M. and R.B. provided required inputs and played critical role in shaping the paper, while providing field level information and graphical representation of the findings; P.K.S. and R.K.A. led the farmer surveys in the field and guided the project implementation team across the initiative, the key findings from the farmer survey have emerged out of their surveys; D.T. and C.L. provided valuable insights and overall guidance from the global context and helped in shaping the paper across review process. All authors have read and agreed to the published version of the manuscript.