Artificial recharge by floodwater spreading estimated by water balances and groundwater modeling

Water harvesting and artificial recharge have been the main and parsimonious solution for 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 and artificial recharge in many arid countries. In the present study water balance calculations and groundwater modeling were utilized to investigate the performance and hydrological function of an improved water harvesting technique called floodwater spreading system in arid Iran. The recharge amount varied from a few hundred thousand cubic meter per month during drought periods to about 4.5 million cubic meter per month during rainy periods. 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. With a balanced pumping, however, this research showed that the floodwater spreading 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.