A conceptual framework for the economic evaluation of water harvesting

Abstract

Water harvesting technologies capture runoff and recycle it for productive use. Recently there has been renewed interest in the use of this technology in arid and semi-arid areas of the world. Despite the long history of water harvesting it has not been widely adopted. A conceptual framework was developed for the economic evaluation of water harvesting. The framework included all relevant agronomic, engineering and economic factors along with the necessary daily meteorological data to incorporate the effect of the different size and timing of weather events. The framework developed was used to investigate the economic feasibility of water harvesting for sorghum grain production at two locations in Texas. The results show large variations in profit from year to year. Two of the three technologies are shown to be more profitable than dryland farming at the two sites studied. The framework was found to be well suited to the task as it adequately dealt with the complexity of the issues and was simple to use. This will aid future users in identifying their data requirements and research agendas. Water harvesting was found to be another complex technology which has benefits in some locations. Adoption of the technology is constrained by the limited profit potential of water harvesting, the variability of water harvesting profits and the knowledge required to successfully use the technology. The profits from water harvesting can be increased by the production of higher value and more water responsive crops, the development of cheaper technology and the development of techniques to make better use of the rainfall in wet years.