Development of a model for design of water harvesting systems in small scale rainfed agriculture

Abstract

In arid and semi-arid regions, water harvesting systems can augment water supply for crop production purposes. The functioning of this type of system is controlled by three major factors: weather, crop and soil characteristics. In particular, the weather factors vary stochastiscally and thus, need to be predicted on the basis of their probability of occurrence. Furthermore, long-term historical data is scarce in the arid regions. Consequently, the simulation approach is a good alternative for designing the system. This study developed a micro-computer based model, SSWHS89.BAS, for design of small scale water harvesting systems for perennial crops. The model uses elements of a simulation computer program, CLIMATE.BAS (Woolhiser, 1988), to generate daily rainfall, maximum and minimum temperature and radiation data and predicts evapotranspiration and runoff data from a deterministic computer program, PENMNSCS.BAS for the location of interest. The model was used to determine the characteristics of a water harvesting system in a vineyard field at Sonoita, Az.