【作者】 刘孝盈；

【导师】 吴斌；

【作者基本信息】 北京林业大学 ， 水土保持与荒漠化防治， 2008， 博士

【摘要】 结合国家“九五”和“十五”三峡工程泥沙问题攻关课题—“嘉陵江典型小流域水土保持减沙效果研究”课题,以嘉陵江流域为研究区,运用基础理论知识和最新研究进展成果,以现场调研、资料分析、经验公式计算和模型验证等手段,通过多种水土保持减沙研究方法系统辨析了嘉陵江流域不同水土保持单项措施,不同水土保持组合措施和不同尺度的流域水土保持减沙效果。通过对嘉陵江流域内治理的胖土地沟与未治理的白米沟流域进行比较,在降雨条件相同时,径流量与断面平均含沙量、时段径流量与输沙量关系,显示了治理流域径流量与含沙量(输沙量)关系较为平稳,波动不大、且含沙量小。未治理流域两者关系波动较大,且有随径流量增大含沙量(输沙量)增大趋势。在一次降雨条件下,水保综合措施减沙效果对流域出口断面的水、沙影响明显。通过对嘉陵江中尺度流域的水土保持措施减沙研究,得出:蟠龙河流域经过综合治理后,减沙总量以农业+工程措施、生物+工程措施所占比重相当,生物+农业措施所占比重较小。单位面积减沙效益最高的则是生物+农业措施的组合。蒙溪河流域三类水保治理措施组合中,农业+生物措施居三种水保措施组合减沙量之首。同时农业+生物措施单位面积减沙率也大于其它两种水保治理措施组合,其减沙效果十分显著。根据流域降雨产沙模型计算结果看,90年代以来,流域水保治理措施实施以后减沙效益明显。而且,随着水土保持措施的不断深入实施,越往后期,减沙效益越明显。研究表明李子溪流域后期水土流失状况较前期有了明显好转。通过对嘉陵江大尺度流域的水土保持措施减沙研究,得出:三峡入库沙量减少主要是由于嘉陵江来沙量减少所致。根据水保分析法计算,嘉陵江流域水保治理后(1989-1998)干支流各测站年平均减沙量占治理前的百分数在33.8%-62.7%之间,且由于水土保持措施将发挥越来越大的减蚀作用。单从1989-1998年减沙幅度(输沙量减小幅度为66.2%)来看,嘉陵江减沙效果相当突出。分析流域来水来沙的变化、降雨落区分布、水库工程的拦沙、人为因素(如采沙)的影响等几个因素的减沙影响量并将其影响剔除后,流域水土保持措施发挥的减水减沙效益为:嘉陵江流域水土保持措施的减水约在1%～3%之间,减沙效益约在10%～25%之间。在RULSE方程基础上改进的流域年输沙量计算新方法,可以对流域的年泥沙输出量进行较准确的计算和预测。嘉陵江流域的流域输沙量模拟值与实测值波动趋势一致,且相对误差都控制在25%以内,对于条件复杂的大型流域而言,模拟效果已比较理想。川中丘陵区水保法、水文法对河流同一测站减沙计算成果归纳及对比看出,同一河流测站水文法研究的河流减沙量均大于水保法研究的河流减沙量;并且有水文法的减沙幅度基本是干流大于支流,而水保法的减沙幅度基本是支流大于干流。嘉陵江流域“长治”工程(水土保持措施)对不同等级流域河流的减沙幅度,1989～1996年平均为4.0%～17.2%;1996水平年为7.5%～31.06%。水土保持治理对河流的减沙幅度(比重)随河流流域面积的增大而减小。研究表明各单项水保措施蓄水保土作用的影响因素非常复杂,各主要影响因子(降雨、植被、土壤、坡度等)在不同条件下的作用千差万别,水保措施减蚀作用有很大不确定性。所以,在不同的治理流域,水保措施综合治理导致流域下游出口断面减水减沙效益的波动范围较大。更多还原

【Abstract】 This paper is based on the research subject of "9th five-year and 10th five-year Key Research Programs "sediment reduction of soil and water conservation in typical small watershed of Jialingjiang River" to systematically analyze sediment reduction effects of single soil conservation measures, different combination of conservation measures and different scale watersheds by exercising basic knowledge and most advanced recent research results and by means of site investigation, model simulation, data analysis and many kinds of research methodology of sediment reduction of soil and water conservation.Through the comparison between managemed Pangdigou baisn and unmanaged Baimigou basin in the Jialingjiang baisn,by the way of the relationship of the average runoff and the sediment quantity on profile,and time runoff and sediment with the same rainfall conditions, it’s showing that relationship of runoff and sediment at the managed watershed is more stable , less volatile, and small sediment; while the relationship of unmanaged Watershed is not volatile, and there is increasing sediment with runoff increasing trend. Under one rain condition, it’s markedly the effect of the Soil and Water Conservation comprehensive measures to reduce of water and sand exporting cross-section of the river basin.On the research of the soil and water conservation measures to reduce sediment at the middle scale of the Jialingjiang baisn, it’s drawn that in the Panlong River with comprehensive management, the total amount of reduced sand is in the combination between engineering and agricultural measures and the combination between biological and engineering, but the combination between agricultural and agricultural measures for a smaller proportion. Per unit area by the sand-effective is the combination between the biological and agricultural measures. Among the three combinations in the Mengxihe basin, the biological and agricultural is the best. At the same time this combination to reduce the sand rate at per unit area is better than the other two and the effect is very significant. According results of the rainfall-sediment model, the reducing effects of soil and water have gained apparent benefits after management measures since the 90’s. Moreover, with the deepening of soil and water conservation measures, more to the latter part of the sand is going with the more obvious benefits. Research shows that the combination between biological and agricultural has significantly better than the other two.On the research of soil and water conservation measures to reduce sediment in the large-scale Jialingjiang Basin, it’s conclusion that: reducing the amount of sand of the Three Gorges storage is mainly due to decreasing sediment.According to the analysis of soil and water conservation method, tributary stations was taken to the average percentage accounted for 33.8%-62.7% in the Jialingjiang basin after management compared to former from 1989 to 1998, and the soil and water conservation measures will play an increasing role in reducing erosion.Improved method on the basis of RULSE to calculate annal sediment is a new way that can provide more accurate calculations and forecasts. Jialingjiang basin basin fluctuations of simulated data and measured data has the same trend, and the relative error is less than 15% in control, so the simulation results have been satisfactory on the conditions for large-scale complex basin.At the Hilly region in Sichuan taking the method of soil and water conservation and hydrologicalmethods to analyse the same station.we can conclusion that results of hydrological way are greater than the other way; And the main stream is greater than tributary by the hydrological way,but it’s opposite by the method of water and soil conservation.According to Reducing amount of the different grades river range in the Jialing baisn caused by "Changzhi" project (soil and water conservation measures), it’s an average of 4.0 percent to 17.2 percent from 1989 to 1996; for the year 1996 is 7.5 percent to 31.06 percent. Effect of Soil and water conservation is becoming small with the baisn’s area increaseing.Research shows that the impact of individual water and soil is very complex, the role of the major factors (rainfall, vegetation, soil, slope, etc.), has huge diversity in different conditions, so the effect is uncertainly. Therefore, in a different managemed baisn, the sediment reduction effect caused by soil and water conservation measures fluctuated the larger scope.更多还原