Tools for assessing water dynamics in rainfed agro-ecoystems

This is a compendium of smaller projects that were previously stand-alone activities. Understanding the dynamics of water variability is essential to managing water in rainfed agricultural systems. Conventional approaches are driven largely by biophysical data, disregarding farmers’ behaviors, responses and strategies. The Water Dynamics (WD) component aims to reconcile scientific (remotely sensed) descriptions of the dynamics of water variability with small-holder farmers’ perceptions, concerns and responses. This is essential to devise well-targeted policies and interventions that can improve livelihoods, as well as optimizing water management and agricultural production. Studies are being conducted in two different agro-ecologies, each with different options in terms of water management: Fogera, Blue Nile (terracing and SWC); and North Central province, Sri Lanka (tanks). MODIS data (available daily for 15 years) are processed and analysed to derive a range of standard products that describe spatial and temporal variability of water at landscape scales. These are compared with survey data describing small-holder perceptions and management responses. A second component uses participatory 3D mapping (P3DM) of land and water resources in the Jeldu catchment, to integrate local knowledge and technical hydrological modelling approaches, with specific emphasis on gender-differentiated views of landscapes and land use. P3DM has been developed and tested very successfully at village scales in 2014. Application of the approach at both village and watershed scales complements work being done under ILSSI to integrate hydrological modelling across scales (ILSSI IDSS, combining SWAT, FARMSIM and APEX). Preliminary work to set up P3DM for the Jeldu catchment was undertaken in 2014. The actual mapping exercise which involves several days of working intensively with the community, was conducted in early 2015. A third component, also ongoing, is assessing the extent and sustainability of groundwater resources in the Cambodian (GWCam) floodplain, to contribute to increased agricultural productivity and decreased agricultural risk for small-holders. The project is based on: • Interviews with local well drilling contractors, to compile their knowledge of the extent of the resource, including flow rates and depth to groundwater in different areas • Collation of results from existing hydro-geological studies • Re-establishing measurements in wells monitored by MOWRAM, iDE and JICA in late 1990s through to 2008, to examine long-term trends in water levels in aquifers which are currently being exploited. A parallel project (under AAS) will examine patterns of use for domestic and agricultural purposes, and institutional issues around sustainable management of groundwater at village level (however, as of November 2014 the status of this project is uncertain, due to revision of the AAS program) A fourth component is completion of an on-going activity exploring key drivers of successful irrigation schemes in SSA by examining irrigation mosaics – small, medium, and large scale irrigation schemes in Ethiopia, Tanzania, and Ghana.