Impact of quarrying coarse gravel from river channel

The construction of the Gezhouba Project consumed a total concrete volume of 1 1.04million m 3 , in which the aggregates are sand and gravel from the river bed . To meet the needs of the concrete production and other aspects, a large amount of sand and gravel was quarried in downstream river stretch from Zhenchuanmen to Huyatan during the construction of the Project, with a total quarrying amount of 33million m 3 . As a consequence, the wet season water level has been lowered evidently in the following years. For the discharge of 4 OOO m 3 ∕s, the water level at the Yichang station has dropped, from 39.69 m to 38.66 m. Tlie minimum design navigable water depth of the shiplocks and the downstream approach channels can only meet the current navigation conditions, but the design water depth requirement of 4.5 m.