变化情景下的漳卫南运河流域水量水质模拟

SIMULATION OF WATER QUANTITY AND QUALITY UNDER CHANGING SCENARIOS IN THE ZHANGWEINAN RIVER BASIN

漳卫南运河流域是我国一个水资源短缺、水质恶化的典型流域.本文应用SWAT模型,结合设置的9种变化情景(包括降雨量、灌溉量、点源排放量、面源污染量),模拟了流域内主要站点(辛集、元村、合河、庆云、四女寺、临清、观台和淇门站)的径流量、总氮、总磷质量以及流域蒸散发在不同情景下的响应.结果表明:降雨量增加25%,将增加径流量147%、总氮50.2%、总磷83.3%、蒸散发8%;灌溉量减少10%,将增加径流量约4%,降低蒸散发3%;点源污染按达标排放将减少总氮24%、总磷8%;按环境容量排放将减少总氮15%、总磷9%;按排放量消减15%,将减少总氮7%、总磷15%;面源污染量减少10%,将减少总氮4%、总磷2%.为了增加入海流量、减少入海污染量,最佳情景组合(即降雨量维持现状、灌溉用水量减少20%、点源按达标排放、面源污染量减少20%),将增加径流量43.6%,总氮和总磷含量减少29.9%和14.2%.这些结论可为漳卫南运河流域的水量配置和水质污染控制措施提供一定的科学依据.

Zhangweinan River basin is a typical area with the striking water scarcity and water quality degradation in China. Using SWAT model, this paper simulated the responses of water quantity and quality to 9 differing scenarios （e.g. changes of precipitation, irrigation, point and non-point sources pollutant discharges） in the river basin. Results showed that the increment of 25% in precipitation would potentially increase streamflow by 147%, TN 50.2%, TP 83.3% and ET 8%, respectively. The reduction of irrigation by 10% would possibly correspond to the rise of 4% in streamflow and the declination of 3% in ET. Decreasing of the point source pollutant discharge to the national wastewater discharge standard would contribute to the decrease of 24% in TN and 8% in TP, and if the discharge is within the local environmental capacity, the contributions to the decrease of both quantities would be 15% and 9%, respectively. The TN and TP could be reduced by 7% and 15% if the point-source pollutant discharge decrease by 15%. Smaller declinations in TN （4%） and TP （2%） would occur in the case of the decrease of 10% in non-point source pollutant discharge. For the increase of streamflow and decrease of pollutant to the Bohai sea, the best scenario （stable precipitation, decrease of both irrigation and Non-point pollution by 20%, standard point source pollution discharge） would result in the increase of streamflow by 43.6%, reduction of TN and TP by 29.9% and 14.2%.These results should have significant implications to the water resources allocation and pollutant control in the Zhangweinan River basin.