Rainfall and Erosion Simulation Laboratory Soil Conservation and Watershed Management Research Institute: Characteristics, Capabilities and Applications

Rainfall simulation is frequently employed in soil erosion and related processes studies. A rainfall simulator was constructed in Soil Conservation and Watershed Management Research Institute (SCWMRI)، which is superior to other existing simulators in country. This simulator consists of some parts such as; water supply، rainfall boom، tilting flume، runoff collection and storage system، control keyboard and laboratory. Rainfall boom has 6 nozzles which introduce a distribution of drop sizes from height of 7. 75 m. Tilting flume consists of flow generation section، drainage part، slope control facility adjusting to 60%، and runoff collection system. Rain Intensity can be controlled by water pressure، number of active nozzles، their distance and pattern، so different intensities ranges 35 to 125 mm h-1 are simulated with coefficient of uniformity more than 90%. Depending on rain intensity، mean drops diameter varies from 1. 64 to 2. 15 mm and terminal velocity ranges 5. 70 to 6. 78 m s-1. Besides، the kinetic energy of falling drops varies from 16. 24 to 22. 97 J m-2 s-1. This simulator can generate rainfall and or runoff separately or simultaneously. So، it is possible to study raindriven and or flow- driven processes under laboratory conditions.