The Optimization Principle of Storage Capacity of Small-Farm Reservoir in Rainfed Agriculture

抄録

  This study aims to develop a simulation model that provides the direction of how to design the capacity of a small-farm reservoir (SFR) for supplemental irrigation in rainfed agriculture. The model describes the water balance of an agricul-tural system that consists of an SFR, and the catchment and irrigation areas where peanuts or rice is cultivated. Simulations were conducted for two crop seasons during October 2013 and June 2014 with climate data in Gondangrejo, Central Java, Indonesia. The SFR capacity was either adequate, that is, the SFR supplied sufficient irrigation water throughout the crop seasons, or inadequate, the SFR failed to supply irrigation water. The optimum SFR capacity was defined as the minimum of the adequate capacity for given catchment and irrigation areas. Simulation results were compared with actual cases of five SFRs constructed in the simulation site. The results clarified the range of the adequate SFR capacity for peanut or rice cultivation in the first crop season during the rainy season and in the second crop season partly during the dry season. The model outputs can be utilized for evaluating and designing SFRs in rain-fed agricultural systems.