基于随机暴雨移置方法的城市设计暴雨分析          下载免费PDF全文

周正正  刘曙光  Daniel B Wright 《水科学进展》1990,31(4):583-591

城市地区暴雨洪灾发生频繁，合理计算设计暴雨是解决城市洪涝的重要前提。采用随机暴雨移置方法（Stochastic Storm Transposition，SST），设定暴雨移置区并提取出暴雨目录，通过区域性概率重采样与暴雨空间变换相结合的方式进行降雨频率分析，估计本地化的极端暴雨频率。以上海地区为例，研究发现暴雨移置区内暴雨分布具有空间异质性，暴雨随机移置概率不均，计算得到的设计暴雨方案包含了降雨时空分布信息，在不同重现期下设计暴雨的时空结构存在变异性，说明传统方法中采用的简化雨型和均一化空间分布假设会增加设计暴雨的不确定性。  相似文献   

流域遥感:内涵与挑战   总被引：1，自引：0，他引：1       下载免费PDF全文

吴炳方  朱伟伟  曾红伟  闫娜娜  常胜  赵新峰 《水科学进展》1990,31(5):654-673

遥感在流域综合管理与流域科学研究中得到广泛应用并发挥着不可替代的作用。重点阐述了流域遥感的内涵、进展与面临的挑战，系统总结了相关的流域遥感数据产品。流域遥感研究流域下垫面、水循环、水资源、水灾害、流域生态的遥感解析能力并提供相关的遥感数据产品。流域遥感数据产品正逐步成为不断更新的公共产品和服务，满足了流域管理监测信息及时性、完整性、连续性和高精度的要求。流域遥感与云计算的结合，可降低流域遥感数据产品生成的技术瓶颈；与云服务结合，可降低流域遥感数据产品的应用难度和成本，将是流域遥感走向实用的主流方向，从而为流域综合管理提供全方位的信息支撑。  相似文献   

Comparing alpine watershed attributes from LiDAR,Photogrammetric, and Contour‐based Digital Elevation Models     

Chris Hopkinson  Masaki Hayashi  Derek Peddle 《水文研究》2009,23(3):451-463

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Dynamics in land cover and its effect on stream flow in the Chemoga watershed,Blue Nile basin,Ethiopia     

Woldeamlak Bewket  Geert Sterk 《水文研究》2005,19(2):445-458

The objective of this study was to analyse changes in stream flow patterns with reference to dynamics in land cover/use in a typical watershed, the Chemoga, in northwestern highland Ethiopia. The results show that, between 1960 and 1999, total annual stream flow decreased at a rate of 1 · 7 mm year⁻¹, whereas the annual rainfall decreased only at a rate of 0 · 29 mm year⁻¹. The decrease in the stream flow was more pronounced during the dry season (October to May), for which a statistically significant decline (0 · 6 mm year⁻¹) was observed while the corresponding rainfall showed no discernible trend. The wet season (June to September) rainfall and stream flow did not show any trends. Extreme low flows analysed at monthly and daily time steps reconfirmed that low flows declined with time, the changes being highly significant statistically. Between 1960 and 1999, the monthly rainfall and stream flow amounts of February (month of lowest long‐term mean flow) declined by 55% and 94% respectively. Similarly, minimum daily flows recorded during the three driest months (December to February) showed statistically highly significant declines over the same period. It declined from 0 · 6 m³ s⁻¹ to 0 · 2 m³ s⁻¹ in December, from 0 · 4 m³ s⁻¹ to 0 · 1 m³ s⁻¹ in January and from 0 · 4 m³ s⁻¹ to 0 · 02 m³ s⁻¹ in February (1 · 0 m³ s⁻¹ = 0 · 24 mm day⁻¹ in the Chemoga watershed). In contrast, extreme high flows analysed at monthly (for August) and daily (July to September) time steps did not reveal discernible trends. The observed adverse changes in the stream flow have partly resulted from changes in land cover/use and/or degradation of the watershed that involved destruction of natural vegetative covers, expansion of croplands, overgrazing and increased area under eucalypt plantations. The other contributory factor has been the increased dry‐season water abstraction to be expected from the increased human and livestock populations in the area. Given the significance of the stream flow as the only source of water to the local people, a set of measures aimed at reducing magnitudes of surface runoff generation and increasing groundwater recharge are required to sustain the water resource and maintain a balanced dry‐season flow in the watershed. Generally, an integrated watershed management approach, whereby the whole of the watershed can be holistically viewed and managed, would be desirable. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Simulation of water balance and forest treatment effects at the H.J. Andrews Experimental Forest     

Scott R. Waichler  Beverley C. Wemple  Mark S. Wigmosta 《水文研究》2005,19(16):3177-3199

The distributed hydrology soil–vegetation model (DHSVM) was applied to the small watersheds WS1, 2, 3 in H.J. Andrews Experimental Forest, Oregon, and tested for skill in simulating observed forest treatment effects on streamflow. These watersheds, located in the rain–snow transition zone, underwent road and clearcut treatments during 1959–66 and subsequent natural regeneration. DHSVM was applied with 10 m and 1 h resolution to 1958–98, most of the period of record. Water balance for old‐growth WS2 indicated that evapotranspiration and streamflow were unlikely to be the only loss terms, and groundwater recharge was included to account for about 12% of precipitation; this term was assumed zero in previous studies. Overall efficiency in simulating hourly streamflow exceeded 0·7, and mean annual error was less than 10%. Model skill decreased at the margins, with overprediction of low flows and underprediction of high flows. However, statistical analyses of simulated and observed peakflows yielded similar characterizations of treatment effects. Primary simulation weaknesses were snowpack accumulation, snowmelt under rain‐on‐snow conditions, and production of quickflow. This was the first test of DHSVM against observations of both control and treated watersheds in a classic paired‐basin study involving a long time period of forest regrowth and hydrologic recovery. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Mercury transport in response to storm events from a northern forest landscape     

Joseph T. Bushey  Charles T. Driscoll  Myron J. Mitchell  Pranesh Selvendiran  Mario R. Montesdeoca 《水文研究》2008,22(25):4813-4826

Concentrations and fluxes of mercury (Hg) species in surface waters of forested watersheds are affected by hydrological events. The mechanisms of Hg transport during these events are poorly understood and yet may influence Hg bioavailability and exposure to aquatic biota. Three storm events with varying magnitude and intensity were investigated (June, September and November 2005) at a forested watershed in the Adirondack region of New York State, USA. Concentrations of Hg species increased during these events, both above and downstream of wetlands in the watershed. While Hg flux was higher from wetland drainage, the Hg flux from the upland site exhibited a greater relative increase to elevated runoff. Hg flux was controlled by discharge; however, Hg species concentrations were not well correlated with discharge, dissolved organic carbon (DOC), or total suspended solids (TSS) through the duration of events. A counter‐clockwise hysteresis response of DOC with increasing runoff contrasted with the clockwise response for total Hg, suggesting different contributions from source areas for these solutes. Correspondence with elevated total K and NO₃^? (α < 0·05) during the rising limb of the hydrograph suggests rapid delivery of throughfall Hg, potentially enhanced by hillslope hollows, to the stream channel. As the watershed saturated, stream Hg appears to be derived from the soil Hg pool. Results suggest that particulate Hg did not contribute substantially to total Hg flux during events (<25%). These results emphasize the role of watershed attributes and storm characteristics in Hg transport and bioavailability. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Progress in watershed geography in the Yangtze River Basin and the affiliated ecological security perspective in the past 20 years,China     

Gao  Yang  Jia  Junjie  Lu  Yao  Sun  Xiaomin  Wen  Xuefa  He  Nianpeng  Yang  Tiantian 《地理学报(英文版)》2020,30(6):867-880

Bibliometrics was used to statistically analyze key zones within the Yangtze River Basin(YRB) funded by the National Natural Science Foundation of China(NSFC) and national ministries over the past 20 years. This study determined that funds that derived from national ministries have mainly focused on issues related to environmental pollution, ecological security, technological water regulations, and river basin ecosystems, which offer a better understanding of the national requirements and the scientific knowledge of the YRB in combination with data from the NSFC. Under a background of bolstering the construction of green ecological corridors in the economic belt of the YRB, this study proposes future conceptual watershed research initiatives in this region as a study objective by reinforcing the implementation of the Chinese Ecosystem Research Network(CERN) and by emphasizing the use of new technologies, new methods, and new concepts for the prospective design of frontier research under the perspective of geoscience and earth system science. This study promotes large-scale scientific field and research objectives based on big science and big data.  相似文献   

黔中小流域水体C、S同位素特征及主要风化过程   总被引：1，自引：0，他引：1  

薛彦山  季宏兵  江用彬 《地球化学》2009,38(3):262-272

选取贵州省红枫湖流域四条支流为研究对象,通过对水体中C、S元素浓度及稳定同位素特征的分析,探讨了典型碳酸盐小流域的主要风化过程对流域C、S循环的贡献。红枫湖流域河水中的C同位素组成在-7．47‰--11．68‰之间,硫酸根浓度为295．5～1315．6μmol／L,除受当地煤矿影响较大的区域外,其余部分水体中离子的δ^34S值在-3‰--7‰之内,反映了这些河段中硫化物矿物的氧化的影响。通过质量守恒的方法,得到硫化物的氧化、蒸发岩溶解以及大气输入对河水硫酸根离子的贡献率分别为63．8％、30．8％和5．4％。来自硫酸对碳酸盐岩、碳酸对碳酸盐岩以及碳酸对硅酸盐岩风化的DIC比例为1：3．58：1．37,三种不同的风化过程对区域二氧化碳的净吸收量为7．97×10^9mol／a。  相似文献   

基于三方向搜索的DEM中洼地处理方法   总被引：2，自引：1，他引：1       下载免费PDF全文

李辉  陈晓玲  张利华  李长安 《水科学进展》2009,20(4):473-479

数字高程模型(DEM)是流域参数提取的基础,然而DEM中普遍存在的洼地和平地影响了流域水系的自动提取,因此洼地去除方法成为研究的热点。针对现有洼地去处方法存在的问题,提出了一种基于"三方向搜索"的洼地处理方法。该方法通过对洼地及其周围网格高程值增减来达到去除洼地的目的,避免了传统填洼方法大规模的对DEM进行增高处理。实验结果表明,该算法简单易行,能有效的去除洼地,消除DEM提取的河网中的伪河道及"平行线"现象;且对DEM中高程值的改动较小,从而较大限度的保留了原始地形信息。  相似文献   

小流域生态经济系统可持续发展评价 --以东北低山丘陵区黑牛河小流域为例   总被引：24，自引：0，他引：24  

戴全厚  刘国彬  刘明义  王跃邦  WANG Yuebang 《地理学报》2005,60(2):209-218

以黑牛河小流域为例,在详细分析东北低山丘陵区小流域可持续发展现状的基础上,对该小流域的可持续发展状况进行定量评价：从效益显著性、资源与环境可支撑性和系统运行稳定性3个方面,选择31个因素作为参评因子,建立评价指标体系;采用精度较高的均方差法确定指标权重,以消除人为经验主观判断,提高评价的客观性和准确率;运用递阶多层次综合法建立二级层次指标(效益显著性、资源与环境可支撑性和系统运行稳定性)评价模型,多目标线性加权函数法建立流域系统综合评价模型,评判出了该区小流域的二级层次指标和综合指标的可持续发展水平,并有针对性的提出了小流域可持续发展的具体对策和建议。  相似文献