IMHE OpenIR  > 山地灾害与地表过程重点实验室
三峡库区紫色土小流域RUSLE模型研究
Alternative TitleStudy on Revised Universal Soil Loss Equation for Purple Soils Small Catchment in the Three Gorges Reservoir Region
Language中文
俱战省
Thesis Advisor文安邦
2015
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Name博士
Degree Discipline土壤学
Keyword三峡库区 Rusle模型 地形因子修正 137cs 210pb 泥沙平衡
Abstract三峡库区是我国水土流失最为严重的地区之一,库区土壤侵蚀产生的泥沙淤积和面源污染是水库安全运行和效益发挥的主要环境问题。为了防治库区水土流失,急需开展土壤侵蚀定量评价研究。修正通用土壤流失方程(Revised Universal Soil Loss Equation,RUSLE)是开展土壤侵蚀定量评价的主要手段。但是三峡库区山高坡陡、坡面破碎(短坡)、地貌呈阶梯状特征,这种特殊的地形条件与基于缓坡、长坡条件下构建的RUSLE模型截然不同,更重要的是,基于中低分辨率DEM提取的库区坡面坡度并不能描述地块坡度变化,然而这一明显差异在现有的研究中均被忽略,迄今尚未有研究对此因素及其影响进行系统研究。 论文以三峡库区腹地重庆忠县申家河的两个典型小流域—黄冲子小流域(6.4ha)和工农沟小流域(8.5ha)为研究对象,采用137Cs和210Pb复合示踪技术对塘库淤积泥沙沉积物进行定年,反演小流域不同时期产沙模数,并依据泥沙平衡原理计算小流域土壤侵蚀模数。在地理信息系统(Geographic Information System,GIS)的支持下,引用中国水利普查水土保持情况普查资料和最新成果,确定RUSLE模型各因子值,估算三峡库区小流域土壤侵蚀模数,并与基于泥沙平衡原理计算的土壤侵蚀模数进行比较;在分析库区小流域RUSLE模型适用性及其驱动因素的基础上,修正地形因子(LS因子)算法,建立不同尺度下(坡面和地块)地形因子转换的数学公式,构建适用于库区小流域的修正RUSLE模型,并在库区较大面积的菱角塘小流域和申家河小流域评价其适用性。主要研究结论如下: (1)采用137Cs定年技术得到黄冲子塘库沉积柱和工农沟塘库沉积柱1963年以来的泥沙淤积深度分别为74.07g cm-2和103.44g cm-2,据此计算的塘库沉积柱沉积速率分别为1.45g cm-2 a-1和2.03 g cm-2 a-1;利用210Pbex CRS模式定年技术计算的黄冲子塘库沉积柱(74.07g cm-2~0g cm-2)和工农沟塘库沉积柱(103.44g cm-2~0 g cm-2)沉积速率分别为1.33g cm-2 a-1和2.10g cm-2 a-1,137Cs时标定年法和 210Pbex CRS模式的定年结果基本吻合,2000年对应的黄冲子塘库沉积柱和工农沟塘库沉积柱质量深度分别为17.21g cm-2和33.33 g cm-2。 黄冲子塘库沉积柱1955~1963年、1963~2000年和2001~2014年平均沉积速率分别为4.76 g cm-2 a-1、1.43 g cm-2 a-1和1.13 g cm-2 a-1;工农沟塘库沉积柱1955~1963年、1963~2000年和2001~2014年平均沉积速率分别为3.35 g cm-2 a-1、2.22g cm-2 a-1和1.88 g cm-2 a-1。黄冲子小流域1955~1963年、1963~2000年和2001~2014年产沙模数分别为1620.99 t km-2 a-1、518.88 t km-2 a-1和387.87 t km-2 a-1;工农沟小流域1955~1963年、1963~2000年和2001~2014年产沙模数分别为527.48 t km-2 a-1、270.10 t km-2 a-1和248.39 t km-2 a-1。塘库泥沙沉积速率和小流域产沙模数均呈减少趋势,主要与不同时期的人类活动(1958年大跃进、1980年代初家庭联产承包责任制和2001年退耕还林工程等)有关,但与同期的降雨量关系不密切。 基于泥沙平衡原理计算的黄冲子小流域1963~2000年和2001~2014年土壤侵蚀模数分别为942.48 t km-2 a-1和811.47 t km-2 a-1;工农沟小流域1963~2000年和2001~2014年土壤侵蚀模数分别是270.10 t km-2 a-1和248.39 t km-2 a-1。 (2)基于RUSLE模型估算的黄冲子小流域1963~2000年和2001~2014年土壤侵蚀模数分别为2246.09 t km-2 a-1和868.63 t km-2 a-1;工农沟小流域1963~2000年和2001~2014年土壤侵蚀模数分别为1288.58 t km-2 a-1 和256.07 t km-2 a-1。2001~2014年小流域土壤侵蚀模数明显小于1963~2000年,主要与研究区实施了退耕还林工程有关,但与降雨量关系不大。1963~2000年黄冲子小流域和工农沟小流域中度及其以上侵蚀面积比例分别为37.19%和12.09%;而2001~2014年黄冲子小流域和工农沟小流域中度及其以上侵蚀面积比例分别降至6.88%和0%。 (3)RUSLE模型估算库区黄冲子小流域和工农沟小流域1963~2000年土壤侵蚀模数的相对误差分别为138.32%和377.08%,远大于20%,表明直接采用RUSLE模型估算库区农地小流域会产生较大误差,LS因子取值不合理是导致RUSLE模型估算结果误差大的关键驱动因素,需要对LS因子算法进行修正。建立了库区坡面尺度LS因子与地块尺度LS因子之间转换的数学公式。借鉴该公式后,修正RUSLE模型估算的黄冲子小流域和工农沟小流域1963~2000年土壤侵蚀模数的相对误差分别降至8.14%和11.60%,小于20%,说明修正RUSLE模型估算结果合理;进一步表明本文提出的LS因子修正算法有效、可行。 RUSLE模型估算库区黄冲子小流域和工农沟小流域2001~2014年土壤侵蚀模数的相对误差分别为7.00%和3.09%,小于20%,说明RUSLE模型估算结果合理,其驱动因素主要是小流域C因子平均值随着退耕还林工程的实施大幅减少,导致RUSLE模型估算结果和基于泥沙平衡原理计算的土壤侵蚀模数基本吻合,并掩盖了库区坡面尺度和地块尺度LS因子差距大这一客观事实。 (4)修正RUSLE模型估算菱角塘小流域和申家河小流域的土壤侵蚀模数分别为914.88 t km-2 a-1和1410.69 t km-2 a-1,基于泥沙平衡原理计算的菱角塘小流域1963~2013年土壤侵蚀模数为1128.30 t km-2 a-1。修正RUSLE模型估算菱角塘小流域的土壤侵蚀模数相对误差为18.91%,其估算申家河小流域的土壤侵蚀模数相对误差在-14.50%~2.17%之间,小于±20%,说明修正RUSLE模型适用于三峡库区面积较大的菱角塘小流域和申家河小流域。另外,直接采用RUSLE模型估算菱角塘小流域和申家河小流域的土壤侵蚀模数相对误差分别为80.17%和277.67%,大于20%,更加证实了本文提出的LS因子修正算法有效、可行且实用性强。借鉴本文提出的不同尺度下LS因子转换公式,采用修正RUSLE模型定量评价库区小流域土壤侵蚀状况,可为三峡库区水土流失预测预报、水土保持规划和水土保持效益评价提供技术支撑。
Other AbstractOne of the most serious soil and water losses regions in China is the Three Gorges Reservoir Region (TGRR) suffering from critical environmental problems of sediment siltation and diffusion pollution derived from soil erosion, which threats reservoir security and benefit in the TGRR. It is urgent to estimate quantitatively soil erosion amount for combating soil and water loss in the TGRR. Currently, Revised Universal Soil Loss Equation (RUSLE) plays an important role in predicting soil erosion amount.Unfortunately, the utilization of RUSLE in the TGRR was constrained by topography condition because its slope gradient is very steep and slope length is extremely short which is completely different from that in USA. In addition, slope gradient derived from low-middle resolution Digital Elevation Model (DEM) cannot reflect slope gradient changes under block scale in the TGRR. However, up to date, this difference is commonly ignored by many researchers and there are rarely studies for talking about this topic and its effect in the TGRR. Study area was located in Zhongxian county, Chongqing municipality of middle part of the TGRR and Huangchongzi catchment (6.4ha) and Gongnonggou catchment (8.5ha) from Shenjiahe watershed were selected for carrying out study work. Pond siltation sediment was dated by combination of 137Cs and 210Pb tracer techniques in order to retrospect sediment yield modulus for different periods. Then soil erosion modulus for catchment was calculated on the basis of sediment balance principle. Meanwhile, each factor of RUSLE was determined referring to the latest results of soil and water conservation survey in National census for water resources in China with the help of Geographic Information System (GIS). Accordingly, Soil erosion modulus in catchment was estimated by RUSLE which it was used for comparing with soil erosion modulus calculated by sediment balance principle. Furthermore, adaptation analysis of RUSLE in catchment of the TGRR and its deriving factors were conducted and slope length and slope gradient factor (LS factor) was focused on and needed to be modified, therefore, the transformation equation between hill-slope and block scales in the TGRR was put forward. According to this equation, modified RUSLE was established for adapting catchment in the TGRR. Meanwhile, its adaptation analysis was carried out in large area catchment. The main conclusions were as following: (1) Sediment siltation mass depth for Huangchongzi pond and Gongnongou pond sedimentation core was 74.07g cm-2 and 103.44g cm-2 from 1963 to 2014 year, respectively, with the utilization of 137Cs dating technique. Accordingly, sediment siltation rate for Huangchongzi pond and Gongnonggou pond sedimentation core was 1.45g cm-2 a-1and 2.03 g cm-2 a-1, respectively, during the same period. In addition, siltation rate of Huangchongzi pond sediment core (74.07g cm-2~0 g cm-2) and Gongnonggou pond sediment core (103.44g cm-2~0 g cm-2)was 1.33g cm-2 a-1 and 2.10g cm-2 a-1, respectively, with the help of 210Pb Constant Rate of Supply (CRS) model. From above analysis, it was shown that 137Cs dating result was well consistent with 210Pb CRS model in each pond. According to this conclusion, mass depth of 17.21g cm-2 for Huangchongzi pond sediment core and 33.33 g cm-2 for Gongnongou pond sediment core was dated with the year of 2000, respectively. Average siltation rate of 1955~1963,1963~2000 and 2001~2014 year for Huangchongzi pond sediment core was 4.76 g cm-2 a-1, 1.43 g cm-2 a-1 and 1.13 g cm-2 a-1, respectively. At the same way, average siltation rate of 1955~1963, 1963~2000 and 2001~2014 year for Gongnonggou pond sediment core was 3.35g cm-2 a-1, 2.22g cm-2 a-1 and 1.88 g cm-2 a-1, respectively. In addition, sediment yield modulus of 1955~1963, 1963~2000 and 2001~2014 year for Huangchongzi catchment was 1620.99 t km-2 a-1, 518.88 t km-2 a-1 and 387.87 t km-2 a-1, respectively. Meanwhile, sediment yield modulus of 1955~1963, 1963~2
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/15063
Collection山地灾害与地表过程重点实验室
山地表生过程与生态调控重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
俱战省. 三峡库区紫色土小流域RUSLE模型研究[D]. 北京. 中国科学院大学,2015.
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