Investigation of Effects of Check Dams on Time of Concentration: A Case Study in Watersheds of Eqlid, Marvdasht, and Mamasani Regions of Fars province

Check dams are small structures that reduce slope of stream bed and mitigate flow velocity for an increase in time of concentration and change of flood hydrograph. About 70% of recent watershed management measures for erosion and flood control consisted of check dams’ construction. Considering different function of check dams in reducing discharge (increase in time of concentration), this research carried out to determine function of check dams for increase in time of concentration in three watersheds including Eqlid, Marvdasht and Mamasani in Fars Province. In this research, more than 1000 check dams were investigated in Tavileh-Band, Tange-Shoul, and Jonagan watersheds located in Eqlid, Marvdasht, and Mamasani regions, respectively. Time of concentration before and after Constructed check dams was measured in the field and by theoretical methods. The results of this research revealed that constructed check dams were able to increase time of concentration but this change was different in different areas of study. Increasing concentration in Eqlid watershed was more than watershed of Marvdasht and mamasani.
The results of this research indicated that success of check dams for increase in time of concentration in watershed projects requires correct estimation of discharge, correct selection of critical stream, proper design of check dam dimension, considering optimum interval between check dams and management of check dams’ maintenance.