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Extracting gravel from river beds causes steep slopes and waterfalls and can remove up stream sources of gravel, sand and river sides. With these slopes local fishes become unable to lay eggs or turbulent flows remove their sperms. This paper studies the problems due to gravel extracting from river beds and changing ecosystem. Extracted gravel and sand are washed and processed by the factories near the river and transported to the consuming centers. Washed gravel and sand suspend fine sediments like clay and slit in the river. These fine sediments settle in the river and make impermeable layers in the bed and prevent seepage of surface water to groundwater and increase the dangers of flooding and damaging to the adjacent regions of the river and destroy the environment.