基于SCS模型的跨界小流域物质通量估算——以东莞石马河流域为例

Calculation of masses flux in a transboundary catchment based on SCS model: A case study in Shima River catchment, Dongguan City

为研究无观察资料跨界小流域的降雨-径流过程,物质通量及生态补偿问题,采用SCS（Soil Conservation Service）模型计算东莞石马河流域的月径流量,通过分析不同断面水样化学指标并结合径流量,估算了2012年石马河主要物质通量以及不同行政区污染物贡献百分比.结果表明,石马河流域最大月径流量出现在2008年6月,为9.12×108m3,最小值为8.61×106m3;不同时期的流域水质污染类型差异显著,2012年2月的水样重金属Mn、Zn、Cu和Fe的浓度范围分别为0.38∽0.75、0.09∽0.49、n.d.∽0.09和0.55∽9.86mg/L,6和11月则受N和P的污染,TN和TP浓度范围分别为6.66∽30.05mg/L和0.05∽2.49mg/L;2012年石马河重金属、N和P通量为318.16、12029和203.35t;在3次调查中,行政区对石马河N和P贡献率为惠州（59.78%和45.22%）〉东莞（35.50%和38.92%）〉深圳（4.71%和15.86%）,重金属平均贡献率的排序为东莞（43.90%）〉惠州（42.57%）〉深圳（13.52%）.

Project of Prediction in Ungauged Basins（PUB） was carried out in 2003 to solve the difficulty with regards to calculation of runoff without observation. Few studies focused on the mass fluxes in ungauged basin were reported. To investigate monthly runoff, mass fluxes and ecological compensation in ungauged trans-boundary watershed, monthly runoff was estimated by using SCS model developed by Soil Conservation Service, U.S. Water samples were collected from different sections between varied districts in February, June and November, 2012 to analyze the concentration of N, P nutrients and heavy metals, and main mass fluxes and contribution rates of contaminants from different districts were estimated in combination with the calculated monthly runoff in 2012. The results showed that the maximum and minimum monthly runoff during the investigated periods（1970∽2012） were 9.12×108m3 in June 2008 and 8.61×106m3 which was base flow, and the maximum and minimum annual runoff were 1.75×109m3 and 5.32×108m3 occurred in 1974 and 2006, respectively. Water quality was severely polluted by varied contaminants in different periods. The ranges of heavy metals concentration were 0.38∽0.75mg/L for Mn, 0.09∽0.49mg/L for Zn, n.d.-0.09mg/L for Cu and 0.55∽9.86mg/L for Fe in February, however, the pollution type was converted to nutrients（N and P） in June and November. Concentration of total nitrogen and total phosphorus ranged from 6.66 to 30.1mg/L and 0.05 to 2.49mg/L, respectively. Shima river transported 318.16 tons of metals, 12029.31 tons of nitrogen and 203.35 tons of phosphorus to the Pearl River Delta in 2012. During the 3investigated periods, the average contribution rates of nitrogen and phosphorus followed the sequences as Huizhou（59.78% and 45.22%）Dongguan（35.50% and 38.92%） Shenzhen（4.71% and 15.86%）, and that of heavy metals was given as Dongguan（43.90%） Huizhou（42.57%） Shenzhen（13.52%）.