Document Type : Research Paper
Authors
1 Asistant Professor, Soil Conservation and Watershed Management Research Department, Lorestan Agricultural and Natural Resources Research and Education Center, AREEO, Khorramabad, Iran
2 Asistant Professor, Soil Conservation and Watershed Management Research Department, Tehran Soil Conservation and Watershed Management Research Institute, AREEO, Khorramabad, Iran
Abstract
Evaluation is a fundamental tool for implementation of projects, and is used as a tool to assess their effectiveness. In areas with no evaluation, assessment is difficult. A practical method for overcoming to this problem is basin simulation using mathematical models. This research was implemented in Dadabad Watershed in Lorestan, followed by impact assessment of watershed management operations on basin behavior change on reducing watershed area floods. Mapping and determining the volume of the built structures and their number, status, and characteristics constituted the first step of the research. The HEC-HMS mathematical model was then employed to estimate flood volumes. Results of simulations and comparison of the observed and simulated hydrographs indicated that the model had the required efficiency for simulating the Dadabad Watershed and was very sensitive to the parameters of curve number and initial loss. The capability of the storage ponds in storing runoff was then determined through calculating their volumes. The behavior of floodwater for the various return periods was simulated to determine the response of the watershed to design storms by applying the changes that had happened in the input part of the model. Results indicated that the water storage ponds could collect and store more than 80 percent of the runoff resulting from rainfalls with return periods of 2 and 5 years. In return periods of 10, 25, 50 and 100 years, 63.4, 54.3, 38.8 and 28.6 percent of the runoff stored in the ponds respectively, and the rest left the watershed from its outlet. In general, the water harvesting systems in the Dadabad Watershed could store 236645 m3 of runoff.
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