西蒙得木对金沙江干热河谷生态保护的作用

金沙江干热河谷生态条件恶劣，水土流失严重，对长江流域中下游特别是三峡大坝存在着极大的负面影响。治理长江流域，保护三峡大坝的重要源头是金沙江干热河谷的生态环境建设。西蒙得木生长的生态环境与金沙江干热河谷的生态环境非常相似，并且西蒙得木具有极高的经济价值，因此在金沙江干热河谷种植西蒙得木，既能改良生态环境，又能发展当地经济。     

金沙江对硫酸的缓冲性能分析

本文分析了金沙江对硫酸的缓冲特征，建立了江水的缓冲曲线方程，并且验证了此方程的有效性，证明用此方程预测硫酸进入金沙江后江水pH值的变化情况，其预测准确度在0.2个pH单位内。     

河滩地的开发与利用——以云南小江流域为例

在川滇两省山地和云贵高原之间,分布着的河流谷地中,有大量的滩地资源,如金沙江、雅砻江下游,安宁河、龙川江、小江等中下游,海拔1300m 以下河谷。这一区域,新构造运动强烈,岩层破碎,矿藏丰富,近代以来,由于人类经济活动频繁,森林植被遭到破坏,水土流失严重,河床被大量泥沙淤积,水流散     

省长、市长要做规划环评“明白人”

山雨欲来风满楼。历时三年多的艰难酝酿与博弈，在《条例》实施前夕，中国环保遭遇空前的尴尬，各地正吞食着自酿的污染苦果：金沙江水电违法开发，美丽富饶的金沙江成为记忆；湖南浏阳镉污染、陕西凤翔“血铝”、山东临沂砷污染……一桩桩环境污染事件的背后，折射的正是规划环评的长期缺位。     

运用多元化投融资手段开发金沙江水电资源

金沙江水电资源丰富，占我国理论蕴藏量的16．5％，是全国最大的水电基地。在市场经济日益发达的今天，如何运用综合手段进行投融资以解决资金瓶颈问题，进一步开发金沙江水电资源使其尽快体现经济价值和为“西电东送”提供有力支撑是值得探讨的问题，这也将为其它基地的后续开发提供理论依据和经验支持。通过对该地区水电资源开发战略意义和现状的分析，明确提出了可以采取并综合运用的各种投融资手段。     

长江口泥沙和沉积物中磷酸盐存在形态的研究

本文根据长江口河段特性及河段中排污口分布特点，疏稀合理地设置监测站点。在长江口河段布点采样、实验室分析的基础上，对长江口泥沙和沉积物中磷酸盐的存在形态进行分析研究，得到了长江口泥沙和沉积物中及沉积物不同粒径中各形态磷的分布特性，其结果对长江口水质管理、污染控制具有现实意义。     

宜宾市主要江河水质现状及污染防治对策

本文根据对宜宾市主要河流多年的地表水质监测数据和污染源排污状况的综合分析，阐明了金沙江，岷江，长江宜浓段的水环境质量状况和污染成因，提出了水污染防治对策，为政府决策提供了科学依据。     

冰雪消融中的玉龙雪山

玉龙雪山位于云南省丽江北25km处，山北麓直抵金沙江。整座雪山由十三座山峰组成，由北向南呈纵向排列，延绵近50km，东西块宽约13km。     

近岸海域的河流沉积物：流理与结局

由于海平面大约在6000年前就达到它现在的位置，当海平面处于低位时，河湾携带的泥沙排入深海区，大多数河流泥沙就停留在近岸海域和内大陆架上，并集聚下来，由于排水量会随气候变化而有极大的变化，这种资料还不适用于预测未来的趋势，在不久的将来，侵蚀速率可能会继续增大，但由于修建的大坝越来越多，水和泥沙输入海中的数量几乎必定会有所减少，低处三角洲的无补偿（甚至加事）下沉，将成为河水与泥沙物质改变流向的主要影响，而着重指出侵蚀的海岸有可能大大后移，相反，淡水流量减少造成的影响，如红树林退缩和沿岩渔产减少，教师是直接可以感觉到的。     

金沙江水电资源梯级开发及其经济发展研究

金沙江流域是我国13大水电基地中水能资源蕴涵量最大的地区，但开发率相对较低。在介绍金沙江流域丰富的水电资源及其开发现状的基础上，分析了加快金沙江水电开发的可能条件和重要意义；针对开发中存在的主要问题，根据市场经济原则和具体情况提出了对策和建议。     

Upstream Sediment‐Control Dams: Five Decades of Experience in the Rapidly Eroding Dahan River Basin,Taiwan

Sedimentation is emerging as a key issue in sustainable reservoir management. One approach to controlling reservoir sedimentation is to trap sediment in hydraulic structures upstream of the reservoir. In the 1,163‐km² catchment of the Dahan River (Taiwan) over 120 “sabo” dams were built to reduce sediment yield to Shihmen Reservoir. Built in 1963 for water supply, Shihmen has lost over 40% of its 290‐Mm³ storage capacity to sedimentation. Most of these upstream structures were small, but three had capacities >9 Mm³. Field measurements and historical data from the Water Resources Agency show most smaller dams had filled with sediment by 1976. The three largest were full or nearly so by 2007, when one (Barlin Dam) failed, releasing a pulse of 7.5 Mm³, most of its 10.4 Mm³ stored sediment downstream. The Central Range of Taiwan is rapidly eroding (denudation rates 3‐6 mm/yr), so geologically high loads make sediment problems manifest sooner. Even in other environments, however, eventually small dams built upstream of large reservoirs are likely to fill themselves, creating multiple small sediment‐filled reservoirs, some located in sites inaccessible to mechanical removal. Our analysis suggests sabo dams do not offer a long‐term basis for controlling reservoir sedimentation in such a high‐sediment yield environment. Sustainable solutions must somehow pass sediment downstream, as would be accomplished by a sediment bypass around Shihmen Reservoir, as now being studied.     

SIMULATING SEDIMENT TRANSPORT IN THE CARSON RIVER AND LAHONTAN RESERVOIR,NEVADA, USA1

ABSTRACT: The discovery of the Comstock Lode in western Nevada in 1859 initiated the use of liquid mercury (Hg) or “quicksilver” to remove gold (Au) and silver (Ag) from crushed ore. Today, Hg is present in historic mill tailings piles, in alluvial deposits adjacent to the Carson River, and in Lahontan Reservoir. Mercury concentrations in Carson River water have been reported as high as 61 μg/L by the U.S. Geological Survey. Fish from Lahontan Reservoir have methylmorcury (MeHg) concentrations as much as four times the 1.0 μg/g limit for human consumption. Since more than 95 percent of total Hg in water can be associated with particulates, the transport of sediment must be quantified to understand the fate of Hg in the system. By linking the RIVMOD hydrodynamic model with the WASP5 water quality model, and using suspended sediment rating curves along with bedload transport equations, reliable predictions of sediment transport can be made. Measured suspended sediment data from the Carson River, and an estimate of annual sediment loading to Lahontan Reservoir, were used to create a calibrated sediment transport model. Model simulations predicted the long term transport of sediment into Lahontan Reservoir, the transport of sediment into Lahontan Reservoir during a flood year (1986 water year), and concentrations of total Hg in the Carson River using an estimate of sediment Hg concentrations. This research will eventually be used with an Hg model to predict the fate of Hg in the river and reservoir system.     

ESTIMATING THE SUSPENDED SEDIMENT LOAD IN RESERVOIRS1

ABSTRACT: The total suspended sediment loads of four north Mississippi reservoirs were determined from measurements of concentrations of suspended sediment in a vertical profile at several locations on each reservoir made during the year. These data were combined with the stage-height and known stage-volume relationships for each reservoir in a numerical integration to determine the total suspended sediment in the water body. Total suspended sediments were estimated using the product of the suspended sediment concentration in the surface water by the appropriate reservoir volume. The averaged ratios of the estimated to measured suspended sediment loads for each reservoir exceeded 0.90. Since the concentration of suspended sediments in surface waters of north Mississippi reservoirs has been shown as highly correlated with spectral reflectance, estimating the total suspended sediment of these reservoirs using remotely sensed spectral reflectance data is possible.     

RESERVOIR SEDIMENTATION1

ABSTRACT: Reservoirs, as well as lakes and estuaries, are subject to sediment accumulation. The rate at which sedimentation occurs is accelerated or diminished by man's activities. Acceptable rates of sedimentation are considered on the basis of costs of sediment storage and removal and a review of reservoirs constructed with sediment removal capabilities is given. The rates of reservoir sedimentation in the United States are summarized based on reliable data obtained from all sizes of reservoirs. Problems confronting the engineer concerning reservoir construction and maintenance are discussed on the basis of these data.     

SEDIMENT RESUSPENSION AND DRAWDOWN IN A WATER SUPPLY RESERVOIR1

ABSTRACT: The magnitudes and patterns of sediment resuspension are assessed in Cannonsville Reservoir, New York, to quantify and characterize this internal source of sediment. The assessment is based on analyses of sediment trap collections from 10 sites over the spring to fall interval of two years. Temporal and spatial patterns in sediment deposition are demonstrated to be driven by resuspension/redeposition processes. Sediment that had been resuspended and redeposited represented 80 to 96 percent, on average, of the depositing solids collected along the main axis of the lake. About 90 percent of the redeposited sediment was inorganic. Increased resuspension caused by drawdown of the reservoir surface and fall turnover resulted in 10 to 50‐fold increases in deposition rates compared to levels observed when the reservoir was full and strongly thermally stratified. Elevated levels of redeposition from resuspension in the reservoir have been driven by both higher water column concentrations of suspended solids and settling velocities. Recurring longitudinal and lateral gradients in resuspension are delineated, establishing that resuspended solids are transported from the riverine to the lacustrine zone and from near‐shore to pelagic areas. Resuspension is demonstrated to cause increases in inanimate particle (tripton) concentrations. Higher tripton levels have been observed in years with greater drawdown. Water quality impacts of the resuspension phenomenon are considered.     

Changes in Streambed Composition in Salmonid Spawning Habitat of the Elwha River during Dam Removal

One uncertainty associated with large dam removal is the level of downstream sediment deposition and associated short‐term biological effects, particularly on salmonid spawning habitat. Recent studies report downstream sediment deposition following dam removal is influenced by proximity to the source and river transport capacity. The impacts of dam removal sediment releases are difficult to generalize due to the relatively small number of dam removals completed, the variation in release strategies, and the physical nature of systems. Changes to sediment deposition and associated streambed composition in the Elwha River, Washington State, were monitored prior to (2010‐2011) and during (2012‐2014) the simultaneous removal of two large dams (32 and 64 m). Changes in the surface layer substrate composition during dam removal varied by year and channel type. Riffles in floodplain channels downstream of the dams fined and remained sand dominated throughout the study period, and exceeded levels known to be detrimental to incubating salmonids. Mainstem riffles tended to fine to gravel, but appear to be trending toward cobble after the majority of the sediment was released and transported through system. Thus, salmonid spawning habitats in the mainstem appear to have been minimally impacted while those in floodplain channels appear to have been severely impacted during dam removal.     

Conversion of a Missouri River Dam and Reservoir to a Sustainable System: Sediment Management1

Abstract: A present and future challenge for water resources engineers is to extend the useful life of our dams and reservoirs. Ongoing reservoir sedimentation in impoundments must be addressed; sedimentation in many reservoirs already limits project benefits and effective project life. Sustainability requires that incoming sediment be moved downstream past the impounding dam. We use Lewis and Clark Lake, the most downstream of the six Missouri River main stem reservoirs, to demonstrate how a reservoir in advanced stages of its project life could be converted to a sustainable system with local benefits exceeding costs by a factor of 1.5. Full consideration of benefits would further enhance project justification. The proposed strategy involves four phases that will take about 50 years to complete. Cost estimates for this potential project range from the quantitative to the plausible, but it is clear that the results justify a full engineering, environmental, and economic study of this model project. If implemented, the project will create scientific knowledge and develop technologies useful for achieving sustainability at many other reservoirs in the Mississippi River basin and beyond.     

Integration of SWAT and HSPF for Simulation of Sediment Sources in Legacy Sediment‐Impacted Agricultural Watersheds

A total maximum daily load for the Chesapeake Bay requires reduction in pollutant load from sources within the Bay watersheds. The Conestoga River watershed has been identified as a major source of sediment load to the Bay. Upland loads of sediment from agriculture are a concern; however, a large proportion of the sediment load in the Conestoga River has been linked to scour of legacy sediment associated with historic millpond sites. Clarifying this distinction and identifying specific segments associated with upland vs. channel sources has important implications for future management. In order to address this important question, we combined the strengths of two widely accepted watershed management models — Soil and Water Assessment Tool (SWAT) for upland agricultural processes, and Hydrologic Simulation Program FORTRAN (HSPF) for instream fate and transport — to create a novel linked modeling system to predict sediment loading from critical sources in the watershed including upland and channel sources, and to aid in targeted implementation of management practices. The model indicates approximately 66% of the total sediment load is derived from instream sources, in agreement with other studies in the region and can be used to support identification of these channel source segments vs. upland source segments, further improving targeted management. The innovated linked SWAT‐HSPF model implemented in this study is useful for other watersheds where both upland agriculture and instream processes are important sources of sediment load.     

OPTIMAL CONTROL OF RESERVOIR RELEASES TO MINIMIZE SEDIMENTATION IN RIVERS AND RESERVOIRS1

ABSTRACT: An optimal control methodology and computational model are developed to evaluate multi‐reservoir release schedules that minimize sediment scour and deposition in rivers and reservoirs. The sedimentation problem is formulated within a discrete‐time optimal control framework in which reservoir releases represent control variables and reservoir bed elevations, storage levels, and river bed elevations represent state variables. Constraints imposed on reservoir storage levels and releases are accommodated using a penalty function method. The optimal control model consists of two interfaced components: a one‐dimensional finite‐difference simulation module used to evaluate flow hydraulics and sediment transport dynamics, and a successive approximation linear quadratic regulator (SALQR) optimization algorithm used to update reservoir release policies and solve the augmented control problem. Hypothetical two‐reservoir and five‐reservoir networks are used to demonstrate the methodology and its capabilities, which is a vital phase towards the development of a more robust optimal control model and application to an existing multiple‐reservoir river network.