Identifying priority watersheds to mitigate flood and drought impacts by novel conjunctive water use management uri icon

abstract

  • Deficit irrigation could be considered as one potential option to improve water productivity and obtain some level of assured income under water scarcity and drought conditions in Central Asia. This article investigates water productivity and economic returns to two varieties of potato crop under four different soilmoisture regimes in Uzbekistan. Results suggest that deficit irrigation may not be considered as an option to improve water productivity of potato crop, particularly when the deficit is high. However, deficit irrigation options could be still considered as a viable option to maintain food security and some assured farm income even under extreme drought conditions
  • New approaches that are cost effective and sustainable are needed globally to better manage flood and drought impacts. Recharging monsoon floodwaters in upstream areas to boost small-scale groundwater irrigation and to protect flood-affected urbanized areas downstream is proposed as one such approach and has been termed 'Underground Taming of Floods for Irrigation' (UTFI). Prospective locations for implementing UTFI are identified using a GIS-based method specifically developed here. There are three main steps to the method: (1) pre-feasibility analysis, (2) spatial data processing, and (3) index determination to rank prospects for establishing UTFI interventions. The methodology was applied to watersheds within the Ganges River Basin in South Asia. Data on the drainage density, flood frequency, flood mortality and distribution, extreme rainfall events, landuse, population density, geology, slope, soil, groundwater level, aquifer transmissivity and economic loss due to floods were used. The ranking and overlay index method adopted in arriving at the final suitability map showed that within the 43 % of the Ganges that is routinely subjected to floods, 68 % of this area had either 'very high' or 'high' suitability. Most important parameters identified from the sensitivity analysis were flood mortality and distribution, flood frequency and extent, drainage density and groundwater level. Suitability index values were generated for watersheds of different sizes which showed that smaller watersheds (100 km(2) or less) provide better results but that up to 1000 km(2) was considered acceptable. These results can be useful for prioritizing areas to apply integrated flood and drought management measures. The approach developed here may be directly transferable to other river basins.

publication date

  • 2016
  • 2016
  • 2016