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International Institute for Geo-Information Science and Earth Observation (ITC) 2003

Evaluating the effect of check dams on flood peaks to optimise the flood control measures : case study in Iran

Roshani, R. (Reza)

Titre : Evaluating the effect of check dams on flood peaks to optimise the flood control measures : case study in Iran

Auteur : Roshani, R. (Reza)

Etablissement de soutenance : University of Twente International Institute for Geo-Information Science and Earth Observation (ITC)

Grade : Master of Science in Geo-Information Science and Earth Observation 2003

Résumé
The recent flood events in Iran positively confirm that most regions are subject to cyclic destructive floods and the extent of damages is increasing. The depth and spatial extent of floods in economical terms demands further research as a priority. Although many studies have concentrated on causes of floods, and these factors have been identified, but the suggested flood control measures just have been concerned within the sub catchments and the effect of those measures at the main outlet of catchment have been neglected. Stream gradient is one of the most important factors in flood acceleration, particularly in mountainous regions. Slope plays an important role in time of concentration (TC). Check dams, as most commonly used measures in watershed management extremely will affect the stream gradient and TC consequently. The effect of slope variation on peak flow was explored. The most effective slope is determined and feasible method for achieving this slope identified. In each case the peak flow reduction index is identified. This index is the most important factor in any decision-making process. GIS environment was used to delineate the boundaries of catchment and sub catchments. Using 100- meter contours a digital elevation model is created. Physiographic factors such as surface slope ; longitudinal profiles of stream channels are calculated. HEC-HMS model was examined to route the rivers, which didn’t simulate feasible results. Convex routing method is used to simulate the inflow and outflow hydrographs. This method of routing is most capable in such cases. Manning equation was used to calculate the peak fl ow after constructing check dams. The result of convex method and manning calculated peak flow was compared. A decision support system (Definite 2 soft ware) selects the most cost effective planning of check dams, which should be constructed within the streams.

Version intégrale (ITC)

Page publiée le 3 février 2018