Delta processes and management strategies in China

Abstract

Abstract Most rivers in China carry high sediment loads, and therefore develop deltas. Many cities have consequently developed near river mouths and have become centers of commerce within China. The increasing population pressure poses new problems and the need for new river basin management strategies. This paper discusses such deltaic processes and the corresponding management strategies for the Yangtze, Yellow and Haihe River deltas, with these being three typical examples. The Yangtze River carries large amounts of water and sediment into the East China Sea. Deltaic islands and shores develop continuously at the river mouth, leading to bifurcations of the channels. Navigation channel dredging and land creation projects are being implemented in the estuary, with these projects intended to narrow and stabilize the river mouth. The present Yellow River delta has developed over the past 147 years as a consequence of siltation and avulsions of the river channel, flooding and sedimentation. Human activities has also sharply changed the delta processes. Oil fields and a new city with a modern infrastructure have been developed on the newly created land. The river channel within the delta is unstable and avulsions often occur. Stabilization of the river channel is necessary for construction of the oil field infrastructure and residences etc. Moreover, the sediment is being used for land creation. The Haihe River mouth is shrinking due primarily to the reduced runoff and sediment deposition from the sea. Dredging is only a temporary solution to this problem. Double guiding dykes, long enough to cut off the high turbidity belt along the coast, are being examined as the main strategy to control sedimentation of the river mouths. Sediment transported by coastal and oceanic currents is also being used for land creation