As the second largest religious metropolis in the world and the second largest city in Iran, Mashhad experienced an uneven and rapid growth from 1950 to 2004. The urban developmant started on a flood plain moving toward a mountain, covering first the alluvial fans and then scattered on the pediments. It has now started encroaching on drainage basins. This expansion, directly and indirectly, affected the local flluvial systems, making problems for the city itself by exerting pressureson these systems. The indirect effects have showed themselves in the form of a rise in the temperature, a change in the type and intensity of precipitation, and an increase in the volume and intensity of floods. Direct effects include intense morphologic changes in the drainage system due to overexploitation of stone resources, a change the profile of main streams due to the exploitiation of gravel resources, obstruction of water canals by consteuction waste deviation of the main water chanals poor, design of urban drainage and reduction of penetrable surfaces. In this article, the writers, using air photos and satellite images, has compared the geomorphic map of the city of Mashhad and the surrounding areas before the expansion with furthe changes as recorded in the above sources and observed in field studies. The changes are compared with appropriate patterns of change and the problem resutting from the imposition of unreasonable pressures on fluvial systems are discussed.
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