用DRAINMOD模型预测不同气候条件下排水及来水量对湿地水文的影响

水量减少是目前威胁湿地生存的一个重要原因.本文采用原美国农业部水土保持局(现美 国自然资源保护局,US-NRCS)所推荐的水管理模型DRAINMOD,根据该局1991年所 建议的湿地水文识别准则,利用不同气候条件下的降水资料,对湿润地区由于排水而引起湿 地水文情势的变化,以及干旱地区湿地形成过程中所需要的基本水量进行了预测分析.模拟结果表明对于年降水量大于1 000 mm的温暖湿润地区,在没有人工排水的情况下,湿地特征十分明显;当排水间距大于150 m时,仍可在50%的年份内满足湿地判别准则的湿润条件.而 对于年降水量小于250 mm的干旱模拟区,形成满足生长期内湿润时段的最小来水量在初春( 3月)时为173 mm,在生长期末(11月)为155 mm,分别是同期月平均降雨量的22倍和16倍 .

Predicting Effect of Drainage and Inflow on Wetland Hydrology under Different Climatic Conditions with DRAINMOD

Drainage and reduced water inflow are important reasons threatening the existence of wetlands at the present time. Based on the hydrologic criteria published by USDA-SCS in 1991, we conducted a modeling analysis with the field hydrology model-DRAINMOD on the change of wetland hydrology. The analysis focused on the change in water volume due to artificial drainage in humid areas and reduced inflow in arid areas. The model simulation results show that in humid areas with annual precipitation more than 1 000 mm, wetland hydrologic criteria can be easily satisfied with no artificial drainage. When drain spacing is larger than 150 m, half year still have wetland hydrology. For an arid area with annual precipitation less than 250 mm, minimum base inflow required to maintain wetland hydrology in the growing season is 173 mm and 155 mm, respectively, for the beginning and ending months of the growing season, which are 22 and 16 times of the average precipitation of the two months.