Impact of Mechanical and Biological Watershed Treatments on Surface Runoff

Abstract

Floods are common types of water-related natural hazards that cause not only destruction and loss of lives but also erosion and sedimentation. Soil and water conservation (SWC) techniques such as mechanical treatments (placing check dams) and biological treatments (vegetation restoration) are being applied to reduce the velocity of runoff and mitigate the impact of floods. In this research, we evaluated four different SWC scenarios to see how the watershed responds to those watershed treatments. We calibrated and validated a rainfall-runoff model to simulate the impact of biological and mechanical treatments on peak discharge and volume of the runoff in Bishebone watershed in the north of Iran. Simulation of peak discharge for before and after watershed treatments for floods with return periods of 2 to 100 years shows that, the combination impact of mechanical and biological treatments on floods with return period of 100 years is 6.95 to 9.94 percent. Results also show that the impact of mechanical treatments on floods with higher return periods is relatively more than that of shorter return periods.