Artificial recharge by floodwater spreading estimated by water balances and groundwater modelling in arid Iran

Water harvesting and artificial recharge have been a traditional solution to water scarcity problems in the arid and semi-arid Middle East for thousands of years. These techniques are increasingly being encouraged, and recently there has been renewed interest to find improved methods for water harvesting and artificial recharge in many arid countries. In this study, water balance calculations and groundwater modelling were utilized to investigate the performance and hydrological function of an improved water harvesting technique, referred to as the floodwater spreading system, in arid Iran. The recharge amount in the floodwater spreading system studied varied from a few hundred thousand cubic metres per month during drought periods to about 4.5 × 106 m3 per month during rainy periods. However, the gain through artificial recharge was diminished by excessive ground- water abstraction by numerous newly drilled pumping wells. Hence, the groundwater declined in spite of the artificial recharge. However, this research showed that, with balanced pumping, the floodwater spreading system could be an efficient way to increase groundwater resources in arid and semi-arid areas. Further research is needed to optimize the floodwater harvesting system to improve its management in view of the uncertain frequency and magnitude of inflow