|
|
|
| Soil loss tolerance in the Loess Plateau based on the healthy function of the lower reaches of the Yellow River |
| Zhang Shijie1,2,Jiao Juying1 |
| 1.Institute of Soil and Water Conservation,Chinese Academy of Sciences and Minister of Water Resources,712100,Yangling,Shaanxi;2.Design Institute of Water Conservancy and Electric Power,543002,Wuzhou,Guangxi: China |
|
|
|
|
Abstract Based on previous researches on critical flow of different sediment concentration under equilibrium between scouring and deposition and pollutants concentration in the lower reaches of the Yellow River,using the daily flow and sediment yield of Huayuankou and Gaocun hydrologic station,we calculated the critical sediment discharge,which is 6.54×108 t in average year,8.83×108 t in high flow year and 3.95×108 t in dry year with an average of 6.44×108 t,when the lower reaches of Yellow River is in equilibrium between scouring and deposition.Taking ammonia nitrogen and total phosphorus as indicators,we analyzed the non-point source pollution caused by water and soil loss in anmenxia,Huayuankou and Gaocun section,and got the critical sediment discharge,which is 7.93×108 t and 5.20×108 t in Sanmenxia to Gaocun interval averagely,when the lower reaches of Yellow River up to the standard of Ⅲ and Ⅱ water quality based on environment quality standards of surface water.Considering equilibrium between scouring and deposition and water quality criterion as the constraint conditions of the healthy function of he lower reaches of the Yellow River,and combining the reduced sediment discharge by water conservancy and soil and water conservation,average sediment discharge of Toudaoguai hydrologic station,sediment discharge ratio of the Loess Plateau,we obtained soil loss tolerance of Loess Plateau,which is 9.41×108 t or 8.41×108 t when water quality up to Ⅲ or Ⅱ standard with equilibrium between scouring and deposition as well in the Lower reaches of the Yellow River.It provides scientific basis for the soil erosion control in the Loess Plateau.
|
|
Received: 05 September 2010
|
|
|
|
|
|
|
