IWMI at World Water Week 2020

In the Ganges basin, 8268.6 km2 of irrigation command area is waterlogged following monsoon rains. In this study, vertical drain (VD) (L × D, 7 × 1 m) filled with drainage gravel (6.5 m) and coarse sand (0.5 m) is installed in farmer’s agricultural field to minimize the duration of seasonal waterlogging and tested in Mukundpur village, Vaishalli District, Bihar, India. At the experimental site, inundation of rainfall and runoff from surrounding areas along with the seepage from an earthen canal start in September and remain till February, every year which prevents timely planting of wheat in November-end/December. Drainage due to percolation and recharge to groundwater is constrained by 6.4-m thick clay layer, below 0.5-m root-zone, and the groundwater level, which rises to the surface level. VDs were installed to provide a path and allow inundated water to recharge the aquifer, as groundwater level recedes. Groundwater level drop, floodwater infiltration rate, groundwater discharge, and VD capability were estimated through field data. Results show that VDs connected the floodwater to groundwater and transferred the floodwater to the aquifer when groundwater level started to recede. The site was fully drained by the end of December, permitting farmers to plant wheat in January providing cool nights at germination, thus increasing yields.

Improvements in land use and management are needed at a global scale to tackle interconnected global challenges of population growth, poverty, migration, climate change, biodiversity loss, and degrading land and water resources. There are hundreds of technical options for improving the sustainability of land management and preventing or reversing degradation, but there are many sociocultural, institutional, economic, and policy barriers hindering their adoption at large scale. To tackle this challenge, the Dryland Systems Program of the Consultative Group for International Agricultural Research and the UN Convention to Combat Desertification convened an expert group to consider barriers and incentives to scaling technologies, processes, policies, or institutional arrangements. The group reviewed existing frameworks for scaling sustainable land management (SLM) interventions across a range of contexts and identified eight critical actions for success: (a) plan iteratively; (b) consistently fund; (c) select SLM options for scaling based on best available evidence; (d) identify and engage with stakeholders at all scales; (e) build capacity for scaling; (f) foster institutional leadership and policy change to support scaling; (g) achieve early benefits and incentives for as many stakeholders as possible; and (h) monitor, evaluate, and communicate. Incentives for scaling were identified for the private sector, farmers and their communities, and policy makers. Based on these findings, a new action framework for scaling is presented that analyses the contexts where specific SLM interventions can be scaled, so that SLM options can be screened and adapted to these contexts, piloted and disseminated. The framework can help countries achieve land degradation neutrality.

Groundwater use in India, and many developing countries, is linked to livelihood and well-being of village communities. It is, therefore, important to characterise groundwater behaviour and resilience and identify strategies that will help to improve the sustainability of groundwater supplies. The concept of Standardised Precipitation Index (SPI) has been widely used for analysing rainfall drought. In this study, we adapt SPI to understand watertable fluctuations and assess resilience of groundwater supplies vis--vis rainfall variability from one year to the next. The modified SPI, called Groundwater Resilience Index (GRI), represents a normalized continuous watertable elevation variability function. The index is applied to two districts, viz., Udaipur and Aravalli in Rajasthan and Gujarat, India, respectively, to assess its usefulness. To evaluate the association of rainfall variability with groundwater depth fluctuation, SPI was also calculated. The study showed that GRI varies less than SPI, indicating that groundwater availability is less variable than the rainfall in both districts. This means that groundwater increases reliability of water supply for irrigation in both districts. The estimated SPI and GRI at 6-month intervals for the study period show that even though the groundwater is not stressed (normal condition in 75% of the months observed), there is variation in resilience of the aquifer system to drought and extreme events. Overall, the study indicated that the proposed GRI can be a useful tool for understanding watertable fluctuations and assessing groundwater resilience, especially to prioritise areas for groundwater recharge when funds for recharge works are limited.

Overall high annual precipitation in Sri Lanka belies significant spatial and temporal variation in surface water availability. The ‘dry zone’ comprising two-third of Sri Lanka’s land area receives significantly less rainfall and has high precipitation rates and a five-month dry season. Nevertheless, these regions account for the majority of rice production, the staple crop, thanks largely to the ancient hydraulic civilization based on networks of rainwater harvesting (irrigation) tanks. This manipulation of surface water resources including modern surface irrigation schemes continues to form the backbone of dry zone farming. Groundwater irrigation has remained in the shadows except in the North where surface flows are absent. This scenario is now changing as population growth; poorly maintained infrastructure; commercial agriculture; sectoral competition for water and climate change combine to exert severe pressure on surface water resources. Since the dry zone is also home to a large number of Sri Lanka’s poor households, and a close association exists between high poverty clusters and access to irrigation, the implications of water insecurity for a range of poverty indicators are clear. Not surprisingly, these pressures have prompted an increasing recourse to groundwater in several parts of the dry zone, as governments and farmers recognize the imperative to increase agriculture output, promote crop diversification, and improve agrarian incomes. Yet, with limited groundwater potential, limited detailed knowledge of this resource, and under-developed groundwater-oriented institutions, it is far from certain whether future groundwater exploitation can steer away from anarchy.

This paper develops a conceptual framework with an indicator-based approach to assess Climate-Smart Villages (CSVs) and applies it to case study sites in Lao PDR (Ekxang CSV), Cambodia (Rohal Suong CSV), and Vietnam (Tra Hat CSV) in Southeast Asia. The intensification, extensification, diversification, commercialization, alteration of practices, use of common lands, migration strategies that can augment climate resilience, farm income, assets, and food security are assessed based on a composite index of the strategies and key outcome variables. The study demonstrates a method that can be applied widely for assessing climate-smart agriculture strategies and finding possible entry points for climate-smart interventions. The influence of gender in resource control and livelihood strategies is also discussed. It is also evident that the climate-smart interventions can augment different livelihood strategies of farmers and enhance the developmental and climate resilience outcomes. There is a need to prioritize the possible interventions in each case and implement them with the help of donor agencies, local institutions, and government offices.

In the Tana River Basin in Kenya, six Regional Circulation Models (RCMs) simulating two Representative Concentration Pathways (RCPs) (i.e., 4.5 and 8.5) were used as input to the Soil and Water Assessment Tool (SWAT) model to determine the possible implications for the hydrology and water resources of the basin. Four hydrological characteristics – water yield, groundwater recharge, base flow and flow regulation – were determined and mapped throughout the basin for three 30-year time periods: 2020–2049, 2040–2069 and 2070–2099. Results were compared with a baseline period, 1983–2011. All four hydrological characteristics show steady increases under both RCPs for the entire basin but with considerable spatial heterogeneity and greater increases under RCP 8.5 than RCP 4.5. The results have important implications for the way water resources in the basin are managed. It is imperative that water managers and policy makers take into account the additional challenges imposed by climate change in operating built infrastructure.