Water resources management through rainwater harvesting in arid area

Water harvesting and artificial recharge has been a traditional solution to water scarcity problems in the arid and semiarid Middle East for thousands of years. These techniques are increasingly being encouraged and at present there has been a renewed interest to find improved methods for water harvesting in many arid countries. The objective of the present study was to evaluate the performance and hydrological function of an improved Flood Water Spreading (FWS) system in Iran. This was done by using available observations during a 14-year period together with extensive hydrogeological modeling and water balance approach. The estimated recharge amount in a studied FWS system varied from a few hundred thousand cubic meters per month during drought periods to about 4.5 million cubic meter per month during rainy periods. Thus, the FWS has large influence on the groundwater balance. The gain through artificial recharge, however, was depleted by too much groundwater abstraction by numerous new-drilled pumping wells. Hence, the groundwater declined in spite of the artificial recharge. As a result and in order to reach to a sustainable pumping rate in the studied area, there must be a balance between pumping and recharge to the groundwater storage. With a balanced pumping, however, this research showed that the FWS system could be an efficient way to increase groundwater resources in arid and semiarid areas. Further research is needed to optimize the floodwater harvesting system for improving the management in view of uncertain frequency and magnitude of inflow.