Assessing the Impact of Land-use Changes on Recharging of a Multilayer Aquifer

Human activities and changing in land-use can affect geo-hydrological processes. This paper investigates historical land-use changes over Golestan multilayer aquifer, Northern IRAN, and their impacts on recharges of both phreatic and confined layers. To achieve this goal, three historical land-use maps of 1984, 2005 and 2013 were used. Also the effects of land-use changes on runoff generation potential and groundwater direct recharge have been evaluated using SCS method. Results show deforestation in mountainous region and urbanization in the plain are the most critical problems of the studied area. Forest and rangeland areas in the mountainous district decreased 8.7 and 4 percent, respectively, and totally added to agricultural lands. Effect of land-use changes on groundwater recharge was found to be more than runoff generation and confined layer is more impressed. In recent 30 years, land use changes caused reduction in natural recharge of confined and phreatic layers up to 18.12 and 12.40 percent, respectively. On the other hand, runoff generation potential increased by 14.14 and 4.23 percent, respectively.