Document Type : Research Paper
Authors
1 MSc, Agricultural and Natural Resources Research Center, West Azerbaijan, Iran
2 Assistant Professor, Soil Conservation and Watershed Management Research Institute, Iran
Abstract
Establishing permanent plant cover with economical efficiency is one of the approaches to control water erosion of piedmonts. For this purpose making rain water harvesting micro catchments systems for collecting enough rainwater by increasing surface runoff coefficient of catchment is necessary especially about low daily rainfalls. Created for rainwater catchment systems in arid and semi-arid areas is essential. The project is located in 30 km. Eastern south of Urmia city in West Azerbaijan. The dimension of runoff area is 5×6 square meters. Construction three treatments in four replications. The rainwater plots built with surface treatments of impediment, semi-impediment and natural surface with 4 blocks. That’s located on southern hillside with slope 12 to 15 percent. The Urmia synoptic station selected and prepared frequency of daily rainfall of every month with depths of more than 0, 1, 5 and 10 mm for period of 50 years. The results showed that average frequency of daily rainfalls with depth of equal or more than 1 and 5 mm for warm month (season of plants growth and production) include July, August and September was for every one year and one for every 3 years respectively. So the threshold of daily rainfall for runoff occurrence due to treatments of impediment, semi impediment and natural respectively are 2.5, 3.5 and 4.4 mm and percent of runoff coefficient 41.17, 10.58 and 1.74 for period of May to November of every year. Conclusion is that application of impediment rainwater catchment associated with runoff reserve system on rainy months (April and May) and reserved water distribution system on more water needy months (July, August, September) is recommended.
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