Evaluation of land-use change and its effect on flood hydrograph in Amameh watershed, Tehran Province
Subject Areas :
Maral Pezeshki
1
,
Baharak Motamedvaziri
2
,
Hasan Ahmadi
3
1 - MSc Candidate in Department of Watershed, Science and Research Branch, Islamic Azad University, Tehran, Iran.
2 - Assistant Professor, Department of Watershed, Science and Research Branch, Islamic Azad University, Tehran, Iran.
3 - Professor, Department of Watershed, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Keywords: Amameh watershed, flood, HEC-HMS, Land-use change,
Abstract :
Changes in the land-use pattern has affected hydrological processes in the watersheds and disrupted the natural balance of water flow. In the present study, changes in hydrological components of Amameh watershed as a result of land-use changes from1988 - 2013 were studied. Due to lack of the land-use map in past years, the land-use map was prepared and analyzed by Landsat TM satellite images in the ERDAS Imagine software in 1988. Furthermore, the available information were used to provide land-use map in 2013. Land-use maps of 1988 - 2013 were prepared using ArcGIS software. In existing maps, six land-use classes; class 1, 2, and 3 rangelands, agricultural and garden, arid land, and river-bed were designed. The results showed that Amameh watershed was affected by severe changes in the land-use during the study period, so that the class 1 rangelands to class 2, class 2 to class 3, and even arid land were changed. In addition, the residential areas (villa) were increased from 2.5% in 1988 to 8.4 in 2013. The HEC-HMS model was used to investigate the effect of land-use changes on the hydrological flood hydrograph of Amameh watershed. The results of hydrograph study of 1988 and 2013 showed the volume increase of runoff and peak discharge rates during the 25-year period, and also the watershed runoff coefficient was increased from 0.82 to 0.89.
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