1- Associate Professor, Faculty of Physical Geography, Geography Department, University of Tehran, Tehran, Iran.
2- . Ph.D. Student of Physical Geography(Geomorphology), University of Tehran, Tehran, Iran
Abstract: (11064 Views)
The subjects related to Geomorphologic studies of Tehran metropolis, from assessment aspect that develope d during last half a century are numerous. Investigation of the surface drainage basins and rivers is one of these subjects. Changing the rivers and their natural flood channels without respecting geomorphologic principals and processes in Tehran metropolis will create different kinds of problems and damages for the civilians of Tehran. At present, the drainages of Tehran are supported by three territories: A) Basins ended to Kan River and West bund for flood channel; B) Basins ended to Aboozar channel and Barootkobi and C) Basins ended to the agricultural terrains of the South part of Tehran (Salehabad territory).
In the present work, the above basins along with flood channel network before the development. were pictured by the aid of topography maps of 1970, air photos taken in different period, also geological maps. The domains of all mountainous and urban basins at present situation were determined by the aid of topography maps of 2001 and changes of drainage network. The maximum amounts of aquifer of each basins were calculated by rational analysis method and using Intensity-Duration-Frequency curves of Mehrabad and Saadabad stations for the return periods of 2, 5, 10, 25, 50 and 100 years. By utilization of physiographic characteristics, drainage systems, and their hydrological calculation and by comparing these characteristics with the nature of basins, the geomorphologic limitations of development in the territory surface drainage basins were assessed. The research procedure is based on analytical method. The key instrument of this research was compiling of Geographical Information System by Arc GIS software and statistical method.
The results indicated that basins compile and a change in the direction of surface waters and their conversion to artificial channels augment aquifer and floods. Especially in long return periods, the increment is obvious, and as a result, it increases urban flood hazard. Blocking of the elementary water channels and creating the new ones in domain of Tehran metropolis without considering the geomorphologic and values. Therefore, in order to reduce the damages and to stabilize the basins development, it is a decisive necessity to apply the geomorphologic principles .
Received: 2007/12/19 | Accepted: 2008/04/15 | Published: 2010/10/13