Simulation of water reliability on a small scale water harvesting agrisystem

Abstract

Water harvesting techniques are being studied to determine its potential as an alternative reclamation practice. To assist planners and decision makers in evaluating the water harvesting potential, a procedure is developed by which precipitation and its distribution are simulated and incorporated with a runoff model to forecast the long term availability of harvested water. The output from the stochastic precipitation model and statistically- derived runoff model provide a simulated 100 years of annual precipitation and runoff events. Two reservoirs were designed and evaluated separately using varied seasonal irrigation demands. The sensitivity analysis, of varying the demand, revealed yearly water reliability decreased as the total seasonal irrigation demand approached the mean annual runoff. It was also shown that an appropriate reservoir size could be chosen using the probability distributions of the number of dry reservoir days and the number of days the reservoir overflows.