Inconsistent rainfall has repeatedly damaged paddy crops in Nepal over the last years, even though most agricultural lands are equipped with groundwater wells, contributing to missed national policy targets of food self-sufficiency and slow growth in cereal productivity. In a recently published article, Cereal Systems Initiative for South Asia (CSISA) researchers explore the drivers of smallholder farmers’ underuse of groundwater wells to combat in-season drought during the monsoon rice season in Nepal’s breadbasket — the Terai.
The study finds that several barriers inhibit full use of the groundwater irrigation infrastructure and proposes support pathways based on existing technologies.
A key issue is farmers’ tendency to schedule irrigation very late in an effort to save the crops when in-season drought occurs. By this time, rice crops have already been damaged by lack of water and yields will be decreased. High irrigation costs, especially when pumping equipment is rented at monopolistic rental rates, are a major factor of this investment aversion. In addition, private irrigation is a relatively new technology for many farmers making productive water use decisions.
After deciding to irrigate, queuing for pumpsets, tubewells, and repairs and maintenance further increase irrigation delays. Some villages have only a handful of pumpsets or tubewells shared between all households, so it can take up to two weeks for everybody to irrigate.
CSISA provides the following suggestions for three spatially nested support pathways to address these issues and support farmers in combatting monsoon season drought.
Raising awareness on the importance of timely irrigation
To avoid yield penalties and improve operational efficiency through better matched pumpsets, CSISA has raised awareness through agricultural FM radio broadcasts on the strong relationship between water stress and yield penalties. Messages highlight the function of the plough pan to keep infiltration rates low and encourage farmers to improve irrigation scheduling. Anecdotal evidence suggests that improved pump selection may decrease irrigation cost by up to 50%, and CSISA has initiated follow-up studies to develop recommendations for farmers.
In addition, timely irrigation often requires social interaction in purchasing fuel, transporting and installing pumps, or shared use of irrigation equipment. These activities pose risks of COVID-19 exposure and transmission and therefore require farmers to follow safety and hygiene practices which may cause further delays to irrigation. Raising awareness about the importance of timely irrigation therefore needs to go hand in hand with safe and hygienic irrigation practices. This information has been streamlined into the CSISA ongoing partnerships and FM broadcasts.
Improving community-level water markets through increased focus on drought preparedness and overcoming liquidity constraints
Farmers can save time by taking an anticipatory approach to terms and conditions of rentals instead of negotiating them when cracks in the soil are already large. Many pump renters also reported that pump owners are reluctant to rent out pumpsets if renters cannot pay up front. Given the seasonality of cash flows in agricultural, pro-poor and low interest credit provisions are likely to further smoothen community-level water markets.
Regional investment prioritization
Selectively targeting support and promotion programs in areas experiencing delays in access to pumpsets and groundwater wells can help farmers in combating monsoon season droughts.
Furthermore, the study shows that these delay factors differ across districts and that selectively targeted interventions will be most useful to provide high returns to investments. For example, farmers in Kailali reported that land access issues due to use of large bullock carts to transport pumpsets and fuel shortages constitute a barrier for 10% and 39% of the farmers, while in Rupandehi maintenance and tubewell availability were reported to be of greater importance.
As drought is increasingly threatening paddy production in Nepal’s Terai region, CSISA’s research shows that several support pathways exist to support farmers in combatting droughts. Sustainable water use can only be brought up to a scale where it benefits most farmers if all available tools including electrification, solar pumps and improved water level monitoring are deployed to provide benefits to a wide range of farmers.
Read the full article in Water International:
Anton Urfels, Andrew J. McDonald, Timothy J. Krupnik & Pieter R. van Oel (2020) Drivers of groundwater utilization in water-limited rice production systems in Nepal, Water International, 45:1, 39-59, DOI: https://doi.org/10.1080/02508060.2019.1708172
Comments
In reply to "Hello - I am curious as to…..." by Anna Brenes
Hi Anna!
Thank you for your interest. Some data and quite extensive local knowledge exists and farmers, well drillers and local government officials do use the existing knowledge to guide groundwater development and use. In general, available information, abstraction patterns and experience of neighboring regions - e.g. in West Bengal where water tables have not been falling despite electrification of irrigation wells - indicate that sustainable use rates are not likely to be crossed in the near term future.
However, the detailed data and information that do exist, are patchy and, for various reasons, little work has been done on aggregating and sharing existing knowledge, filling the gaps, and developing and communicating a comprehensive understanding of local and regional sustainable use limits. Improving the understanding of the region's aquifer characteristics, dynamics, and spatial heterogeneity is definitely a bottleneck to sustainable and integrated resource management and planning.
As you point out - in the absence of a better understanding of sustainable use patterns, balancing investments in productive groundwater use with monitoring and responsive action towards local indicators of groundwater depletion is crucial to ensure sustainable rural development in the region.
I hope this answers your question and I am happy to further discuss any detail.
Best wishes, Anton.
A few details:
In each district of the Tarai, 10 monitoring wells are being checked on a monthly basis by the Groundwater Resource Development Board and we are exploring options to improve the monitoring system. Importantly, there's a temporal component. The available monitoring data shows that the monsoon recharges to the aquifers to the same level each year after decreasing by ca. 4m, on average, during the dry season. Groundwater use in the Tarai is currently estimated to be ca. 22% of annual recharge (although this number is lower for the estimated potential recharge under higher use rates) with 1-3 flood irrigations in rice being common and agriculture accounting for ca. 97% of groundwater withdrawals. But patterns differ across villages and districts.
Also, well interference is definitely an issue to be coordinated. I am not aware of published studies on well interference (or single-well drawdown) across the Tarai that are accessible. But some records and local maps exist with respective offices/organizations. Anecdotally, shallow tube well (i.e. <200ft, <6inch) irrigation has limited interference with neighboring wells. For, deep tube wells (i.e. >200ft, >6inch), in pre-monsoon times (i.e. before the aquifers are refilled), farmers report that deep tube well use can dry up shallow wells for drinking and irrigation during the time of pumping. Where this problem occurs, communities have locally enacted some restrictions on deep tube well use when water levels are low. Also, farmers generally report great differences in groundwater dynamics and availability between villages and sub-regions in the Tarai. For sustainable resource management and planning, a more granular and localized understanding is required and proper governance models to be developed and shared!
Hello - I am curious as to whether or not groundwater well levels are closely monitored in this region of Nepal. Extreme aquifer drawdown rates for flooding rice paddies could result in unsustainable water use for irrigation and impact other crops, as well as the availability of water for human consumption. Have piezometer studies been done to understand patterns around pumping wells and what a sustainable drawdown rate is?