一种黄土区土壤侵蚀强度遥感调查新方法   总被引：2，自引：0，他引：2  

张兵  王向军  童庆禧 《国土资源遥感》1996,7(4):36-39

通过对TM图像的线性纹理提取和密度统计,首先获得了黄土丘陵区沟谷密度图,然后由沟谷密度反演区域土壤侵蚀强度。这种方法避开了影响土壤侵蚀量的诸多复杂因子。可直接从水土流失的外在表现---沟谷密度来反推土壤侵蚀强度。研究结果证明,这种方法对快速调查大范围黄土丘陵区的土壤侵蚀强度是十分有效的。  相似文献   

冰碛湖溃决泥石流流量计算方法   总被引：1，自引：0，他引：1  

党超  褚娜娜  张鹏 《冰川冻土》2019,41(1):165-174

冰碛湖溃决泥石流是高山高寒地区一种常见的灾害类型,虽爆发频率低,但造成的危害极大,该类型的泥石流防治是区域开发建设中必须要面对的问题,而流量计算又是其核心问题之一。以西藏地区近100 a以来的冰碛湖溃决实例为基础,探讨了溃口深度的计算方法;以逐渐溃决模型和配方法为基础,分析了冰碛湖溃决泥石流的容重峰值流量与洪峰演进计算方法的适用性与流程;通过案例的对比研究,探讨了计算模型参数率定与误差来源。结果表明：瞬间溃决模型高估了冰碛湖溃决泥石流的峰值流量,泥石流的预测值偏保守;而逐渐溃决模型更接近于冰碛湖溃决的物理机制,在冰川U型谷内,可不考虑泥石流的堵塞作用,泥石流的峰值流量预测值与实测值较吻合;在冰川U型谷外或近沟口段则需考虑泥石流的堵塞作用。文中提出的计算模型作为冰碛湖溃决泥石流防治工程参数设计的依据是可行的。  相似文献   

Sediment yield variability in Spain: a quantitative and semiqualitative analysis using reservoir sedimentation rates   总被引：3，自引：0，他引：3  

Gert Verstraeten  Jean Poesen  Joris de Vente  Xenia Koninckx 《Geomorphology》2003,50(4):327-348

An existing dataset of area-specific sediment yield (SSY) for 60 catchments in Spain that was retrieved from sediment deposition rates in reservoirs [Avendaño Salas, C., Sanz Montero, E., Rayán, C., Gómez Montaña, 1997. Sediment yield at Spanish reservoirs and its relationship with the drainage basin area. In: Proceedings of the 19th Symposium of Large Dams, Florence, 1997. ICOLD (International Committee on Large Dams), pp. 863–874] reveals that catchment area alone explains only 17% of the variability in SSY. In this study, an attempt to explain the remaining variability in SSY was made using a quantitative and a semiqualitative approach for 22 catchments. During a field survey, the 22 selected catchments were characterised by topography, vegetation cover, lithology, shape and the presence of gullies in the broad vicinity of the reservoir. This information was used to develop a factorial scoring index model that provides a fairly accurate and reliable prediction of SSY. A classical multiple regression model using climatic, topographic and land use properties derived from regional datasets could not explain as much variance as the qualitative index model, nor did it appear to be as reliable. The same conclusion could be drawn when using the CORINE soil erosion risk map of southern Europe. The low prediction capability of the multiple regression models and the CORINE soil erosion risk map could be attributed mainly to the fact that these methods do not incorporate gully erosion and that the land cover data are not a good representation of soil cover. Both variables have been shown to be of great importance during the field surveys. Future assessments of SSY could be quickly and efficiently made using the proposed factorial scoring index model. In comparison with other models, which demand more data, the index model offers an alternative prediction tool.  相似文献   

西藏波密米堆冰湖溃决浅议   总被引：4，自引：0，他引：4  

李德基  游勇 《山地学报》1992,(4)

1988年7月15日西藏波密米堆终碛湖发生溃决,最大洪峰流量1270立方米/秒,溃决水量540万立方米,形成了大规模的泥石流-洪水灾害。冰湖溃决的原因是;终碛堤存在渗漏薄弱环节,堤内有埋藏冰;持续高温和冰川融水的潜热使埋藏冰融化,由潜蚀而迅速发展成管涌导致溃决。  相似文献   

The development of montane arroyos and gullies     

William L. Graf 《地球表面变化过程与地形》1979,4(1):1-14

Field investigations in the Front Range of Colorado, U.S.A., confirm that the spatial distribution of vegetation in watersheds exerts strong control on the entrenchment of streams in the montane zone. When tractive force in channels exceeds threshold values of resistance on the valley floors, cutting of arroyos begins, producing forms that change allometrically. An algorithm based on the Cooke Method for discharge, the Manning Equation for depth of flow, and the DuBoys Equation for tractive force can be used to evaluate force for observed and experimental conditions. In small (<5 km²) basins in the Front Range of Colorado, forces for the 10-year discharge commonly range from 1 to 5 dynes, but the resistance offered by valley floors is usually unable to withstand forces from channel flows greater than 2 dynes. Biomass of vegetation on the valley floor exerts significant control on the trenching process, with threshold values of biomass commonly between 1.5 and 9 kg/m², the range of semi-arid vegetation cover. Thresholds exist in the montane erosion system for gradient, mean biomass in the basin, biomass on the valley floor, channel roughness, and channel width. Each threshold value, however, depends on the interrelationships among other variables in the system. Manipulation of the vegetation cover is the primary human impact on the montane channels, and management of the distribution of vegetation offers the most efficient method of maintaining the stability of channels.  相似文献   

安徽省祁门县石荣沟泥石流发育特征及发展趋势分析     

孙凤贤 《中国地质灾害与防治学报》2003,14(2):103-108

石荣沟区降雨量丰富，多暴雨。支沟纵坡陡，沟谷内分布的变质砂岩、泥页岩，由于受多组构造裂隙的共同作用，滑坡、崩塌发育，这为泥石流的形成提供了物质条件。文章在野外调查的基础上，从地质、地貌、水文地质、气候和人为活动等条件入手，对石荣沟泥石流的发育条件、灾害特征和发展趋势进行了分析，并初步预测其未来变化趋势，为流域的综合治理提供了科学依据。  相似文献   

Assessment of sidewall erosion in large gullies using multi-temporal DEMs and logistic regression analysis   总被引：3，自引：0，他引：3  

J. A. Martínez-Casasnovas  M. C. Ramos  J. Poesen 《Geomorphology》2004,58(1-4):305-321

Although in the last decades gully erosion has been a thriving research field, few studies have specifically addressed the contribution and location of sidewall erosion processes in gullies. In this paper, sidewall erosion in some large gullies in a Mediterranean area (Anoia-Penedès, NE Spain) is mapped and assessed for two time intervals (1975–1995 and 1995–2002), using detailed digital elevation models derived from aerial photographs at a scale of 1:5000 to 1:7000. Logistic regression analysis is applied to compute the probability of occurrence of gully sidewall erosion from terrain variables. The results confirm the complex nature of sidewall processes, whose intensity is most probably related to rainfall characteristics. Prolonged wet soil conditions in the period 1995–2002, together with the large and high-intensity rainfall of an extreme event occurred on 10th June 2000, help to explain the different sediment production rates: 16±0.4 Mg ha⁻¹ year⁻¹ in 1975–1995 and 83±6.3 Mg ha⁻¹ year⁻¹ in 1995–2002. The logistic regression analysis revealed that gully-wall slope angle was the main factor controlling gully sidewall failure. In gully walls with high slope angles, tension crack development is the main process promoting wall collapse. The application of the logistic regression model showed a high overall accuracy (87%) but over 50% of commission and omission errors for the class of interest (sidewall erosion), in agreement with the variance explained by the model.  相似文献   

西藏波密冬茹弄巴的冰雪融水泥石流   总被引：6，自引：0，他引：6  

吕儒仁  李德基 《冰川冻土》1989,11(2):148-160

  相似文献   

Debris flow initiation and sediment recharge in gullies   总被引：2，自引：0，他引：2  

Drew Brayshaw  Marwan A. Hassan   《Geomorphology》2009,109(3-4):122-131

Landslides that enter gullied low-order drainages can either initiate debris flow or stop, depositing sediment in the channel. This process is one of the most common ways that debris flows initiate, but little attention to date has been paid to evaluating the factors that affect whether or not the initial landslide will become a debris flow or deposit sediment in the channel. Statistically significant parameters that determine whether slope failures become debris flows or act to recharge in-channel sediment are channel gradient, angle of entry of failure into the channel, initial failure volume, and the amount of in-channel stored sediment. Steeper channels, low angles of entry, lower volumes of in-channel sediment, and larger initial failures were more likely to result in debris flows. This study found that as the volume of in-channel stored sediment increased, the volume of initial failure required to initiate a debris flow also increased. This result calls into question the simple supply-limited model of cyclical debris recharge and debris flow in low-order gullied drainages and suggests a negative feedback mechanism between debris accumulation and debris flow susceptibility.  相似文献   

南伊沟水体水化学及氢氧同位素特征分析     

刘沛  黄峻川  喻晓 《中国地质调查》2023,10(1):91-99

南伊沟是林芝地区重要水源涵养区,研究南伊沟水体水化学和氢氧同位素特征,揭示“三水转化”规律,对提高林芝地区水体水文地球化学研究程度,支撑当地林水关系研究,服务高原地区水生态保护具有重要意义。运用水化学和氢氧同位素分析方法,分析了地区水化学特征、水岩作用情况和水循环特征。结果表明：南伊沟水体为极低矿化度淡水,地表水水化学类型为HCO₃-Ca·Mg型和SO₄·HCO₃-Ca·Mg型,地下水水化学类型为HCO₃-Ca·Na型;地表水和地下水的水化学离子成分主要受岩石风化控制,离子来源主要受碳酸盐岩溶解和硅酸盐岩风化影响,地表水中Na⁺、K⁺、Cl^-主要来源于盐岩溶解,同时还受降雨影响,地表水和地下水中Ca²⁺、Mg²⁺主要来源于碳酸盐岩矿物溶解;地下水和地表水水岩作用较弱,对比上游雅鲁藏布江和拉萨河地表水,大部分δ¹⁸O、δD值具有明显的高度效应和大陆效应;南伊沟枯水年内强烈...  相似文献