四川盆地丘陵区降雨侵蚀与输沙特征
文献类型：学位论文
| 学位类别 | 硕士 |
| 答辩日期 | 2009 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 陕西 |
| 导师 | 焦菊英 |
| 学位专业 | 水土保持与荒漠化防治 |
| 中文摘要 | 四川盆地丘陵区是长江上游人口稠密的农业区之一，由于自然因素和人为因素的影响，导致该区水土流失面积广、强度大，是长江上游水土流失重点产沙区之一，其入河泥沙量的大小直接关系到下游长江三峡工程的使用年限和安危，乃至整个长江流域经济的可持续发展。本文以四川盆地丘陵区为研究对象，选取多年实测降雨资料分析了降雨量及降雨侵蚀力的时空变化特征；利用径流小区及小流域观测站实测资料，研究了自然因素与人为活动因素对土壤侵蚀的影响，并结合水文站实测输沙量资料分析了河流输沙变化特征及河道冲淤情况，并估算了流域泥沙输移比。取得了以下主要研究结果： (1)四川盆地丘陵区大部分地区的年降雨量空间分布总体上是盆周多于盆底，由外而内逐渐减少；降雨年内分配极不均衡，主要集中于5～10月，占全年降水量的78%以上；年际变化也较大，且变化幅度为北部大于中部和南部，西北部大于东南部。顺坡休闲农耕地的侵蚀性雨量标准为11.3mm，多年平均总降雨量中有60%以上属于侵蚀性降雨，7、8两个月年均侵蚀性降雨量和土壤侵蚀量最大。年均降雨侵蚀力R值介于5000～6500MJ·mm·ha-1·h-1之间，主要由≥ 15mm降雨构成，其时空分布特征与降水量相似。(2)多年平均条件下，土壤侵蚀量和径流量均随坡度与坡长的增加而增大；在次降雨条件下，随着降雨量、降雨强度及降雨能量的增加，坡度的变化对坡面产流产沙的影响明显，而坡长变化的影响则不显著。(3)横坡垄作与顺坡垄作相比，减流率相对稳定，变化在35.1%～74.7%之间，而减蚀率变化趋势起伏较大，在8.5%～96.8%之间；林草措施相对于自然坡面的减流效益平均为48.6%和32.3%，减沙效益平均为54.4%和73.8%；梯地多年平均减流量为1.94×104m3/km2，减沙量为2151.0t/km2；淤地坝单坝年均拦沙量为143.7t；小型蓄用水工程平均每年汛期减少地表径流量13650m3，减少输沙量44.2t。(4)休闲裸地年侵蚀量为753.2t/km2，农耕地种植不同作物条件下年均侵蚀模数变化在9.2～15567.7t/km2之间，不同草地径流小区的多年平均侵蚀量变化在45.3～710.8t/km2，不同林地类型下多年平均侵蚀量变化在3.25～620.5t/km2。无论哪种土地利用类型，随着植被覆盖度或郁闭度的不断增大，降雨对土壤侵蚀的影响逐渐减弱，土壤侵蚀就会减轻。考虑土地利用类型、植被覆盖度、种植条件、侵蚀产沙特征等因素，归纳出四川盆地丘陵区不同土地利用类型的多年平均侵蚀模数：旱地为5424.8t/km2，水田为714.8t/km2，裸岩为12428.0t/km2，有林地、灌木林地、疏林地和经济林地的侵蚀模数分别为240.7t/km2、392.9t/km2、2326.7t/km2、514.9t/km2，高盖度草地、中盖度草地和低盖度草地的侵蚀模数分别为139.3t/km2、710.8t/km2、2038.9t/km2。 (5)在嘉陵江中游干流流域以武胜～(亭子口、红岩、赵家祠、清泉乡)区段的水土流失最严重，多年平均输沙模数为1060.4t/(km2·a)，渠江流域则为为罗渡溪～(苟渡口、静边)区段，多年平均输沙模数为2158.4t/(km2·a)，而涪江流域为将军石～甘溪区段，多年平均输沙模数为1730.6t/(km2·a)。在1957～1987年间，嘉陵江中游干流流域输沙模数呈下降趋势，涪江流域有略微降低趋势，与流域内降水量的逐年减少及水利工程的拦沙有关；而渠江流域呈上升趋势，其原因主要是降雨量的增加。(6)1983年与1965年相比，涪江干流河段除涪江桥站断面萎缩外，平武站、射洪站和小河坝站断面均以冲刷为主；支流平通河河床以冲刷为主，梓潼河、安昌河、凯江及魏城河河床均以淤积为主。涪江流域干流及主要支流水文站控制流域的SDR值变化范围在0.04～0.87之间，其中梓潼河流域SDR值变化于0.04～0.2之间，凯江流域SDR值为0.07，平通河流域SDR值为0.6，涪江流域干流不同控制区间内的SDR值变化于0.1～0.87之间。各水文站控制流域的SDR大小与流域控制断面的冲淤情况基本一致。 |
| 英文摘要 | The hilly area of Sichuan Basin is one of the most densely populated agricultural regions in China, and the area represents one of the most severely eroded regions in the upper Yangtze River basin because of the purple soils which are highly susceptible to erosion. The sediment yielding from the hilly area of Sichuan Basin are closely related to the service life and safe of Three Gorges Project, even to the sustainable development of the whole Yangtze River basin. Thus, the hilly area of Sichuan Basin was chose as the research area, the spatial and temporal characteristics of rainfall and rainfall erosivity, and the effect of natural factors and human activity factors on soil erosion were studied based on the measured data from runoff plots, small watersheds and rainfall stations. Meanwhile, the sediment transporting characteristics, scouring and silting changes of large riverbed sections and sediment delivery ratio (SDR) were analyzed based on the hydrological observation data. The main conclusions are including: (1)The spatial distribution of annual rainfall was gradually decreased from outside to inside in the hilly area of Sichuan Basin. The annual distribution of rainfall was concentrated in May to December, and accounted for above 78% of annual rainfall. The yearly variation of rainfall was also large, and much more variation in the north part than in the middle and south part, while much more variation in the northwest than the southeast. The erosive rainfall standard of downslope fallow arable land was 11.3mm, and more than 60% of the rainfall was erosive rainfall averagely. The most of annual average erosive rainfall and soil erosion amount was appeared in July and August. The annual average rainfall erosivity (R value) was between 5000 and 6000MJ·mm·ha-1·h-1, R value was mainly consisted by the ≥ 15mm rainfall, which took up above 80% of the annual R value. The spatial distribution of the rainfall erosivity was similar with the rainfall.(2)The annual average of soil erosion amount and runoff volume increased with the increasing of slope gradient and slope length. The effect of slope gradient on runoff and sediment yield was significant as more as the rainfall, rainfall intensity and rainfall energy increasing under the individual rainfall conditions, while the effect of slope length was not significant. (3)The runoff reduction of contour ridge cultivation was stable compared with downslope ridge cultivation which varied from 35.1% to 74.7%, while the sediment reduction was fluctuant widely which varied from 8.5% to 96.8%. The average runoff reduction benefit of forest and grass measures was 48.6% and 32.3% respectively and the average sediment reduction benefit was 54.4% and 73.8% seperately. The average runoff reduction and sediment reduction amount of terrace land was 1.94×104m3/km2 and 2151.0t/km2 respectively. The annual average silting amount of check dam was 143.7t. The runoff reduction amount was 13650m3 by water storage engineering in flood season, and the sediment reduction amount was 44.2t.(4)The annual average erosion modulus of fallow bare land was 753.2t/km2, of farmland growing with different crops varied from 9.2～15567.7t/km2, of different grass lands varied from 45.3～710.8t/km2, and of different forest lands varied from 3.25～620.5t/km2. The erosion modulus of different land use types were summarized in the hilly area of Sichuan Basin by considering the effect of vegetation coverage, crop condition and sediment yield characteristics. The average erosion modulus of dry land, paddy field and bare rock was 5424.8t/km2, 714.8t/km2 and 12428.0t/km2 respectively, of forest land, shrub land, open forest land and economic forest land was 240.7t/km2, 392.9t/km2, 2326.7t/km2 and 514.9t/km2, while of grass lands with high coverage, moderate coverage and low coverage was 139.3t/km2、710.8t/km2、2038.9t/km2. No matter what the land use types is, the effect of rainfall on soil erosion decreased as the coverage of vegetation increasing. (5)The soil loss in the section from Wusheng to Tingzikou, Hongyan, Zhaojiaci and Qing quanxiang was the most severe with annual average sediment discharge modulus of 1060.4t/(km2·a) in the middle main stream of Jialing River basin. While in the Qu River basin, the section from Luoduxi to Goudukou and Jingbian had the biggest annual average sediment transport modulus 2158.4t/(km2·a), and the section from Jiangjunshi to Ganxi is 1730.6t/(km2·a) in the Fu River basin. Among 1957 and 1987, the sediment transport modulus in the middle main stream of Jialing River basin and in the Fu River basin showed downtrend because of the decrease of rainfall and hydraulic engineering, while the sediment transport modulus in the Qu River basin showed uptrend mainly because of the increase of rainfall. (6)Based on the data of 1983 and 1965, the riverbed of Pingwu, Shehong and Xiao heba sections were mainly scoured except Fu Jiangqiao section in the main stream of Fu River, and the riverbed of Ganxi section was mainly silted but the riverbed of Zi Tong, Xiaoba, Guanyinchang and Liujiahe sections were mainly scoured in the tributary of Fu River. The SDR value of controlled watershed varied from 0.04 to 0.87 in the main stream and tributary of Fu River, while SDR value varied from 0.04 to 0.2 in the Zitong River , SDR value was 0.07 in the Kai River, SDR value was 0.6 in the Pingtong River, and SDR value of controlled areas varied from 0.1 to 0.87 in the main stream of Fu River. The SDR value in the controlled watersheds was consist with the souring and silting features of the corresponding sections |
| 公开日期 | 2011-07-01 |
| 源URL | [http://ir.iswc.ac.cn/handle/361005/4126]  |
| 专题 | 水土保持研究所_水保所知识产出(1956-2013) |
| 推荐引用方式 GB/T 7714 | . 四川盆地丘陵区降雨侵蚀与输沙特征[D]. 陕西. 中国科学院研究生院. 2009. |
入库方式： OAI收割
来源：水土保持研究所
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