Assessing impacts of agricultural water interventions in the Kothapally watershed, Southern India uri icon

abstract

  • The paper describes a hydrological model for agricultural water intervention in a community watershed at Kothapally in India,developed through integrated management and a consortium approach. The impacts of various soil and water managementinterventions in the watershed are compared to no-intervention during a 30-year simulation period by application of thecalibrated and validated ARCSWAT 2005 (Version 2.1.4a) modelling tool. Kothapally receives, on average, 800 mm rainfallin the monsoon period. 72% of total rainfall is converted as evaporation and transpiration (ET), 20% is stored by groundwateraquifer, and 8% exported as outflow from the watershed boundary in current water interventions. ET, groundwater rechargeand outflow under no-intervention conditions are found to be 64, 9, and 19%, respectively. Check dams helped in storing waterfor groundwater recharge, which can be used for irrigation, as well minimising soil loss. In situ water management practicesimproved the infiltration capacity and water holding capacity of the soil, which resulted in increased water availability by10?30% and better crop yields compared to no-intervention. Water outflows from the developed watershed were more thanhalved compared to no-intervention, indicating potentially large negative downstream impacts if these systems were to beimplemented on a larger scale. On the other hand, in the watershed development program, sediment loads to the streamswere less than one-tenth. It can be concluded that the hydrological impacts of large-scale implementation of agricultural waterinterventions are significant. They result in improved rain-fed agriculture and improved productivity and livelihood of farmersin upland areas while also addressing the issues of poverty, equity, and gender in watersheds. There is a need for case-specificstudies of such hydrological impacts along with other impacts in terms of equity, gender, sustainability, and development atthe mesoscale

publication date

  • 2012
  • 2012