Ecological engineering strategies to reduce flooding damage to wetland crops in central China

Ecological engineering techniques are widely used in Chinese agriculture to reduce wastes and improve efficiency, but rarely to address crop loss asso ciated with flooding. In the middle Yangtze River basin in central China, d ish-shaped areas that formerly contained shallow lakes and marshes are now empoldered for the cultivation of rice, fish and other crops. These areas a re economically productive but regularly experience crop damage due to rain fall amounts exceeding the removal capacity of pumps and drainage canals. A field investigation gathered existing data on landforms, hydrology, agricu ltural and aquacultural practices, and recent flooding events at two scales : Xiaogang Farm, 24 km(2), and Honghu Flood Diversion Area, 2800 km(2). Com puter simulations suggested that local-scale increases in pumping capacity would effectively reduce local flooding damage, but this approach would be less effective if implemented over a wide area. Proposed ecological enginee ring strategies for hood resistance, including converting some low-position area from rice to flood-tolerant crops such as lotus (Nelumbo nucifera) or wild rice stem (Zizania latifolia), and raising dikes around the converted fields to allow passive storage of excess water during heavy rains, may re duce damage at both local and wide scales. (C) 1998 Published by Elsevier S cience B.V. All rights reserved.