Farm ponds in the semi-arid areas of Maharashtra: a case study

By Ankita Yadav

It is widely known that the state of Maharashtra, for the last many years, has frequently faced drought and drought-like conditions.  To deal with this challenge,  a number of policies and interventions have been implemented by State and Union government bodies while various coping mechanisms are being adopted at the local level.

One such intervention is the construction of farm ponds . The State government has introduced schemes like ‘Magel tyala Shettale’, (Farm Ponds on Demand) and ‘Jalyukt Shivar Abhiyan’, while the Union government has also supported farm ponds by allocating funds under schemes such as the National Horticulture Mission (NHM), Mahatma Gandhi National Rural Employment Guarantee Act (MGNREGA), Rashtriya Krishi Vikas Yojana (RKVY), Pradhan Mantri Krishi Sinchai Yojana (PMKSY), etc which also provide subsidy for plastic linings.

Farm Pond

An example of a farm pond in the Sangamner taluka of Ahmednagar district, Maharashtra. Photo: WOTR

Harvesting rainwater is crucial in semi-arid regions of Maharashtra, that receive very low rainfall. As Maharashtra is underlain by hard rock  [1] which have very low porosity, it allows only limited recharge by percolation.  It is also important to note that water resources in semi-arid Maharashtra are fragile and sensitive to human interventions and climate variability. Negative externalities like increasing rates of evaporation and erratic rainfall events are compounding the problem. Hence, farm ponds become a crucial tool in ensuring farmers have access to water in the periods of low rainfall.  In this blog, we take a closer look at farm ponds and their impact, in the context of six selected villages in Sangamner, Maharashtra.

Farm pond study

WOTR’s farm pond study was framed under Adaptation at Scale in Semi-Arid Regions (ASSAR) to understand social, climatic and economic impacts of the practices of storing groundwater on the surface in farm ponds. The parameters considered for economic analysis of farm ponds are: investment costs and benefits of constructions of farm ponds, the procedure of availing government subsidy, change in the cropping pattern and energy consumption, evaporation and land opportunity costs and desire of farmers to have farm ponds.

To ascertain this, a structured questionnaire survey was conducted in six selected villages of Sangamner, Ahmednagar district selected on the basis of the zonal distribution of groundwater vulnerability of villages. As many as 188 households owning farm ponds were interviewed in villages of Gunjalwadi, Dolasane, Karjule Pathar, Wankute, Bhojdari, Jawalebaleshwar which are categorized under ‘high to extremely high’ groundwater vulnerable zones [2]  The Sangamner block has also been declared as having ‘semi-critical’ status of groundwater development by the Central Groundwater Board (2014).

The figure of study area is given below:

Study Area Map

Farm ponds as rainwater harvesting structures

When on the field, we observed that the actual practice of farm pond storage and usage is not in keeping with the original intention of being rainwater harvesting structures. Many farm ponds are traditionally rainwater harvesting structures as groundwater storage structures. The general perception of farmers is that storing groundwater on the surface is securing their own private share of water. A large quantum of water is therefore indiscriminately extracted from the aquifer by selective farmers who are more economically powerful. This puts small and marginal farmers at high risk by creating limited access to groundwater resources.

The data of 206 farm ponds from study villages showed that there has been a deviation from prescribed structure size and designs. The dimensions of farm ponds are prescribed under the ‘Magel tyala Shettale’  as per land holding of farmers viz. 30m*30m*3m is the largest while the smallest size is 10m*10m*3m. A maximum of Rs. 50,000 is received for largest sized farm pond. Upto Rs. 75,000 can also be received for plastic linings under the farm pond scheme of NHM.  To obtain these benefits, one has to follow certain rules and norms while constructing the farm pond viz. dimension of farm pond, scientific site selection of farm pond. However, most of the farm ponds we were observed had dimensions 2 to 3 times bigger than recommendations while many others were constructed without guidance from nominated technical officers of government.

In our interactions, a few farmers said they found the application process for subsidy quite lengthy or difficult due to their lack of familiarity with e-government portals/services. Plastic lining is another  important component of a farm pond. Finding good quality ISI mark plastic lining at low prices is a difficult task for farmers, as a result the small and marginal farmers often struggle to line their farm ponds. Almost 70% of the documented farm ponds in the study area are non-functional due to such various reasons and remain as dead investment.

Evaporation losses

It is important to understand the extent of evaporation losses, if we are to assess the efficacy of farm ponds. The average annual evaporation rate over region was calculated using Penman’s formula [3] (Edward 2003) as 7.7 mm/day.

Table 1 shows the evaporation losses in terms of total volume of water lost to evaporation from standard recommended surface size of 30m * 30m farm pond. For each of study villages, it can be seen that from one single farm pond of 30m * 30m surface, approximately 20-21 tankers of water is lost to evaporation per month. Unfortunately in recent years, all these villages are experiencing drought which is making them more dependent on tankers for drinking water.

Study Villages Average annual Evaporation rate
mm/day
Evaporation rate
m/day
Standard Largest recommended surface dimension 30m*30m Evaporation Losses
Evaporation loss
liters/month
Volume loss per month as number of tanker of 10,000 liters capacity Loss in Rupees as cost of tankers (Rs. 600 per tanker
Gunjalwadi 7.27 0.00727 900 196290 20 11777
Dolasane 7.68 0.00768 900 207360 21 12442
Karjule Pathar 7.72 0.00772 900 208440 21 12506
Jawalebaleshwar 7.63 0.00763 900 206010 21 12361
Wankute 7.87 0.00787 900 212490 21 12749
Bhojdari 7.86 0.00786 900 212220 21 12733

(For the calculation of evaporation rate per village, localised data on temperature, dew point temperature and humidity was used, which was collected from automated weather stations installed in each village).

(ASSAR works actively in the semi-arid regions of Africa and India, through a five-year multi-institutional and multi-scale, interdisciplinary scientific research project) [5]

The opportunity cost of the volume of water used for agriculture was also calculated. If the same volume of water would have been used for irrigation of crops, it would have given production ranging between Rs 11,000 to Rs. 60,000., depending upon the crop chosen. The total volume of water lost to evaporation is very high when all such active farm ponds are considered in a village. In the event that the currently non-functional farm ponds become functional, the losses would become exponential which would lead to huge depletion of groundwater resources. Another important indirect cost is the opportunity cost of land lost in the construction of farm ponds.

Shift in cropping patterns

The shift in cropping pattern of active farm pond owners was also observed from traditional food crops to water-intensive cash crops and horticulture. The LULC assessment of Mula-Pravara sub-basins, that covers the whole Sangamner Block, shows that there is an increase of cropped area and area under horticulture plantations by about 98% and 1601% respectively [6]

This is mainly due to the perception of these farmers that privatizing the water on surface would provide secured irrigation to the crops. As cropping pattern has changed, the frequency of irrigation has increased; subsequently the frequency of groundwater extraction to fill up farm pond has also increased, leading to more borewells being drilled.

Conclusion

The study of general perception among farmers, including farm pond owners and non-farm pond owners, show that farm ponds are considered beneficial in providing water during dry spells. In normal rainfall years, these farm ponds are said to support additional crops grown in Rabi or summer seasons.

However, to make farm ponds truly effective, some changes would have to be made at the policy and implementation level.There needs to be a focus on small sized farm ponds, as these are a better option as compared to large sized farm ponds, in particular for small and marginal farmers. This is due to larger surface area exposed to evaporation in large farm ponds and the greater area these ponds occupy.  In conclusion, there also needs to be an effective monitoring system by the government or local institutions that would ensure that the farm ponds are built according to the prescribed guidelines. This would help make farm ponds both beneficial to farmers and also not strain the existing groundwater resources of the region.

References
  1. Thomas, Renie, and Vijayasekaran Duraisamy. 2018. “Hydrogeological Delineation of Groundwater Vulnerability to Droughts in Semi-Arid Areas of western Ahmednagar district”
  2. Ibid
  3. L. Edward, “A simple formula for estimating evaporation rates in various climates, using temperature data alone”, School of Earth Sciences, Macquarie University, Sydney (Australia), 2003
  4. Duraisamy, Vijayasekaran, Ramkumar Bendapudi, and Ajit Jadhav. 2018. “Identifying Hotspots in Land Use Land Cover Change and the Drivers in a Semi-Arid Region of India.” Environmental Monitoring and Assessment
  5. http://www.assar.uct.ac.za/about/about_ASSAR_project
  6. Duraisamy, Vijayasekaran, Ramkumar Bendapudi, and Ajit Jadhav. 2018. “Identifying Hotspots in Land Use Land Cover Change and the Drivers in a Semi-Arid Region of India.” Environmental Monitoring and Assessment

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