Impact of River Realignment and Land Reclamation on Flood Control and Ecological Habitat in River-estuary-bay System

Abstract

Impacts of engineering works are studied in a complex river-estuary-bay system at Shenzhen in Southern China. The concerned engineering works include river realignment and land reclamation from the bay, which could result in significant effects on local flood control and ecological protection. The variations of water level and inter-tidal wetland areas are investigated with hydrodynamic models under different engineering scenarios. The modeling results show that the flood control apparently benefits from the realignment of Shenzhen River, but the flood-tide interaction in Deep Bay is only slightly modified. Reclamation activity for the purpose of land gain in the north side of the Deep Bay has a very small effect on the flood-tide interaction in the system, but it shadows a variety of impacts to inter-tidal wetlands in terms of different post-reclamation coastlines. Thus, a compromise should be made between the benefits and negative impacts from the engineering works by comparing the given options. The acceptability of various options is identified for various post-reclamation coastlines with negligible, non-negligible but mitigatable, and unacceptable impacts, respectively, in terms of increasing land area gain. Mitigation measures for loss of inert-tidal wetland are also suggested for habitat compensation

Keywords:

• Engineering works
• flood control
• ecological protection
• inter-tidal area