辽河三角洲湿地景观的水文调节与防洪功能

Hydrological Adjustment and Flooding Control of Wetlands in the Liaohe Delta

以辽河三角洲为对象论述了湿地景观的水文功能,重点研究湿地蓄水容量与苇田蒸发散、湿地水更新率、稻田水量平衡等湿地的水文调节功能及人类活动的影响;探讨了湿地水文调节功能的价值估算,三角洲地下含水层的调洪功能;并根据辽河三角洲湿地的景观生态特征和在防洪中的功能,将湿地景观划分出5个功能区,为制定合理的景观规划,为促进三角洲地区的可持续发展服务。

Wetland is the transitive zone between open water body and dry land with some specific properties. Hydrology of wetlands includes water input, output, depth, flow manners, duration and frequency of inundation. Liaohe delta locates on the transitive zone between the Bohai Sea and the dry land, the convergence of fresh and salty water affected both by the sea and inland. These wetlands are playing important roles in hy-drological adjustment, i.e. regulating the water storage, flooding, tidal flow, and surface and ground water exchange by impounding, discharging and evapotranspiration. The function of estuary wetland on hydrologi-cal and flooding control is studied in this paper. It is estimated that the evapotranspiration in the reeds swamp during growth season(June to October) is 722.9 mm, which is 37.5% higher than large water body(E601: 525.9 mm). The water replacement rate in the reed field can reach 95% only when the rains continuously for 11 days and the precipitation reached 912 mm. For the water balance in the paddy field, the total water requirement ranges between 1920 mm and 1860 mm, among which, 31% is from precipitation, and the left is provided by reservoirs. The water usage efficiency is 0.35 at present productivity. Based on the landscape characteristics and functionalities on flooding control, 5 functional areas are designed for the Liaohe Delta: Key protected area; underground storage area; flooding discharge area; flood diversion area in emergency; and flood control drainage area.