【作者】 亢伟；

【导师】 李占斌； 李鹏；

【作者基本信息】 西安理工大学 ， 水文学及水资源， 2008， 硕士

【摘要】 本文以大理河流域为研究对象,运用水土保持学、泥沙运动学、水文学、景观生态学和数理统计学等理论,系统开展了大理河流域坡面水土保持措施减沙机理及其减沙作用变化过程研究。主要取得了如下研究结论:(1)确定了大理河流域坡面水土保持措施的数量和质量。通过资料收集和典型调查,结合遥感影像图和GIS技术,分析了大理河流域坡面水土保持措施数量和质量的动态变化过程。1956年大理河流域有梯田430hm~2;林地3521hm~2;草地451hm~2;到2002年底,大理河流域共有梯田21793hm~2;林地78872hm~2;草地5012hm~2,水土保持治理面积大幅度增加。(2)应用模拟实验和定位观测资料,深入分析了灌草植被措施的减沙机理。结果表明,植被覆盖度因植被类型和生长季节的变化而有所差异,其产沙特征也发生相应的变化;同时灌草植被的空间结构和配置形式对坡面产沙具有深刻影响,植被覆盖度较高的坡面具有更为强大的水土保持功能。(3)进一步分析了大理河流域坡面主要水土保持措施的减沙效益,建立了汛期降雨条件下坡面主要水土保持措施减沙效益的计算公式。结果表明,大理河流域汛期降雨量大于300mm时,梯田的减沙作用减小;林地的覆盖度小于20%时,林地减沙作用不显著,林地覆盖度大于70%时,林地减沙效益不再发生明显变化;草地的覆盖度大于60%时,草地减沙效益不再发生明显变化。(4)确定了大理河流域不同等级坡面水土保持措施的减沙模数。根据流域观测资料和小区观测资料,结合主要水土保持治理措施的质量分析,确定大理河流域一、二、三类梯田的减沙模数分别为155t/hm~2、121t/hm~2和112t/hm~2,一、二、三类林地的减沙模数分别为138t/hm~2、52.5t/hm~2和22.5t/hm~2,一、二、三类草地的减沙模数分别为132t/hm~2、84t/hm~2和63t/hm~2。(5)分析了大理河流域坡面主要水土保持措施的减沙量。由“以洪算沙”计算成果可知,20世纪70、80和90年代大理河流域坡面水土保持措施年均分别减沙量254.6万t、549.2万t和948.6万t。流域1970～2002年坡面水土保持措施年均减沙量724.2万t,其中,梯田年均减沙量197.4万t,林地年均减沙量513.9万t,草地年均减沙量12.9万t。更多还原

【Abstract】 Based on the theory of soil and water conservation,hydrology,landscape ecology,sediment dynamics and mathematical statistical,the sediment reduction mechanism as well as the change process of the sediment reduction effects by soil and water conservation measures on slopes in Dali river watershed was studied.Following conclusions were reached:(1)Determining the quanlity and quantity of main soil and water conservation measures on the slope.Based on data collection and typical investigation,combined with the RS imagine analysis and GIS Technologies,The dynamic process and change tendency of the quantity and quality of soil and water conservation measures on slopes in Dali river watershed was studied. There were 4.3 km~2 terrace land,35.21km~2 forestland and 4.51km~2 grasslands in Dali river watershed in 1956.Until 2002,area by soil and water conservation inceased a lot,and there were 217.93 km~2 terrace land,788.721km~2 forestland and 50.12km~2 grasslands in 2002.The harnessing areas of soil and water conservation rapidly increased.(2)Based on the simulating study and site-specific observation,mechanics of sediment reduction by shrub and herbaceous vegetation was analyzed.Results showed that the vegetation coverage degree,as well as the sediment yield characteristics on the slope varied with the vegetation types and seasons.And the sediment yield on the slope was deeply affected by the spatial structure and deposition model of the vegetations measures.High vegetation coverage degree has stronger function of soil and water conservation.(3)According to the further researches on the sediment reduction effects by the soil and water conservation measures on slope,the formula for the sediment reduction effects calculation was established in the flood season.In Dali river watershed,the results showed that the sediment reduction effects of the terrace land decreased when the rainfalls greater than 300mm in the flood season.The sediment reduction effects of the forestland was not significant when the vegetation coverage degree of forestland was less than 20%.The sediment reduction effects of the forestland had no remarkable change when the vegetation coverage degree of forestland was greater than 70%.The sediment reduction effects of the grassland had no remarkable change on grassland when the vegetation coverage degree of grassland was greater than 60%.(4)The sediment-reducing modulus of different grades of soil and water conservation measures on slope in Dali river watershed was calculated.By the observation data and plots experiment,combined with the mass analysis of the main soil and water conservation measures on slope,the sediment-reducing modulus were calculated as 1.55·10~4t/km~2,1.21·10~4t/km~2 and 1.12·10~4t/km~2 for theⅠterrace land,Ⅱterrace land andⅢterrace land.The sediment-reducing modulus were calculated as 1.38·10~4t/km~2,0.525·10~4t/km~2 and 0.225·10~4t/km~2 for theⅠforestland,Ⅱforestland andⅢforestland.And the sediment-reducing modulus were calculated as 1.32·10~4t/km~2,0.84·10~4t/km~2 and 0.63·10~t/km~2 for theⅠgrassland,Ⅱgrassland andⅢgrassland.(5)The sediment reduction amounts of soil and water conservation measures on slope were calculated in Dali river watershed.The sediment-reducing amounts of soil and water conservation measures on slope were calculated as 254.6·10~4t,549.2·10~4t and 948.6·10~4t for the year of 1970s,1980s and 1990s.The annual average sediment-reducing amounts of soil and water conservation measures was 724.2·10~4t during 1970～2002.The annual average sediment-reducing amounts of the terrace land,forestland and grassland was taken for 197.4·10~4t,513.9·10~4t and 12.9·10~4t.更多还原