The safe use of land resource to avoid flood risk within the lower Yellow River in Kaifeng
开封市黄河滩区土地资源规避洪水风险的安全利用

The Yellow River channel boundary and beach land use within Kaifeng City were mapped in detail by using 2007 SPOT 2.5 imagery, field surveys, and ArcGIS and ERDAS software. The river channel flood fringe lines of a typical 7-year period between 1992 and 2007 (less than 8000 m3/s) were generated from Landsat TM images of annual largest flood peak between 1992 and 2007, in conjunction with hydrological data along the Yellow River. Additionally, the submerged Yellow River beach areas with certain regular flood flows within Kaifeng City were created overlaid with background data. Certain levels of large floods and their potential submerged areas were calculated within the Yellow River beach in Kaifeng (especially over 8000 m3/s) based on the mathematical model of the 'downstream runoff and sediment of Yellow River' together with data obtained from a large cross section of the river channel after 2004. According to land resource management and safety requirements for flood transit within the channel, the current issues regarding the lower Yellow River are discussed, including the increased threat of floods in low beach villages, the infrastructure of agricultural development, the living condition of farmers within this Yellow River beach area, and the negative effects of brick-tile kilns and borrow pits on farmland and farming activities. Four principles of safe land use to avoid flood risk are proposed as follows: 1) protecting and using land resources to improve ecological and economic efficiencies as a whole; 2) utilizing land resources based on suitability; 3) prioritizing 'easily exploitable beach land', such as high and flat beach; 4) exploiting land resources intensively while decreasing beach land utilization rationally. Finally, four zones of safe land use to avoid flood are suggested in Kaifeng beach: a) the risk buffer zone close to the river channel (less than 4000 m3/s, about 200 m from the river course waterfront); b) the zone suitable for cultivated land near the river channel (4000-6000 m3/s); c) the zone of relatively stable land use (6000-8000 m3/s); and d) the zone of stable land use (above 8000 m3/s). At the same time, important measures of safe use beach land resources to avoid flood risk are proposed.