回水计算中流量模数计算方法的探讨

回水水面线计算是河流规划、沿河城市防洪堤设计及水库淹没赔偿范围确定的基本工作。要计算回水水面线,就必须计算流量模数。为此,归纳总结了回水计算中流量模数计算的6种方法,对6种计算方法进行了比较,得到了以第6种方法计算流量模数时取得的水位最高、最安全的结论;并以实际工程为例,对采用各种流量模数计算方法的回水计算结果进行了对比。     

Forecasting impacts of climate change on Great Lakes surface water temperatures

Temperature influences the rates of many ecosystem processes. A number of recent studies have found evidence of systematic increases in Great Lakes surface water temperatures. Our study aims to construct empirical relationships between surface water temperatures and local air temperatures that can be used to estimate future water temperatures using future air temperatures generated by global climate models. Remotely sensed data were used to model lake-wide average surface water temperature patterns during the open-water period in Lakes Superior, Huron, Erie, and Ontario. Surface water temperatures typically exhibit linear warming through the spring, form a plateau in mid-summer and then exhibit linear cooling in fall. Lake-specific warming and cooling rates vary little from year to year while plateau values vary substantially across years. These findings were used to construct a set of lake-specific empirical models linking surface water temperatures to local air temperatures for the period 1995–2006. Hindcasted whole-lake water temperatures from these models compare favourably to independently collected offshore water temperatures for the period 1968–2002. Relationships linking offshore water temperatures to inshore water temperatures at specific sites are also described. Predictions of future climates generated by the Canadian Global Climate Model Version 2 (CGCM2) under two future greenhouse gas emission scenarios are used to scope future Great Lakes surface water temperatures: substantial increases are expected, along with increases in the duration of summer stratification.     

大流量低水头渡槽的水力计算和加大流量时的水面线推算

大流量低水头渡槽根据设计流量和给定水头确定过水断面后,通过加大流量时,渡槽内就会发生非均匀流,需对这种水流情况进行推算,以确定渡槽在通过加大流量时的水面线．而且,由此计算渡槽侧墙高度和结构荷载,确保渡槽的安全．     

湟水流域地表水资源特征

通过对青海省境内湟水流域的降雨、蒸发、径流的地区分布、年内分配、年际变化及近年来的变化趋势进行分析,得出影响本流域径流变化的主要因素是降雨的分布及变化,以及对人类活动对径流量的影响。研究湟水流域地表水资源对三江源及下游地区水资源开发利用和生态环境保护起着举足轻重的作用。     

遗传算法在推求流量—水深关系中的应用

本在标准遗传算法（SGA）基础上，提出一种基于实数编码的遗传算法（RGA），解决了标准遗传算法（SGA）算法及献[1]中华罗庚优选法的循环次数过多、耗时长以及过早收敛、形成局部成等问题。并渴望在水利工程设计中多维、高度非线性等参数优化问题中得到应用。     

Cost-effective Approaches for Sustainable Groundwater Management in Alluvial Aquifer Systems

The consequences of unsustainable use of groundwater are becoming increasingly evident worldwide, particularly in developing nations. Groundwater management is a serious problem in many parts of the world. The prime concern is how to achieve groundwater sustainability. Artificial recharge techniques coupled with water harvesting hold a great promise for groundwater sustainability. The main intent of this paper is to highlight salient cost-effective and easy-to-use methods for augmenting groundwater resources in the alluvial hydrogeologic setting. Based on the intensive field investigation in a groundwater basin of Japan, three low-cost and easy-to-implement recharge techniques are suggested for alluvial aquifer systems, viz., augmentation of river flow, recharge through irrigation/drainage canals, and recharge from paddy fields. The source of recharge water for these recharge techniques is surface water supply. The efficacy of these methods or approaches has been demonstrated. It is emphasized that such cost-effective methods of groundwater recharge are key to sustainable groundwater management in both developing and developed countries. These methods must not be overlooked in the midst of sophisticated and highly expensive methods.     

Impacts of urban areas and urban growth on groundwater in the Great Lakes Basin of North America

The Great Lakes Basin (GLB) holds vast reserves of groundwater, the great majority of which eventually drains to the lakes. Urban growth significantly affects both the quality and quantity of this groundwater and thereby represents a potential threat to the long-term viability of the Great Lakes hydrologic system. Urban areas import, manufacture, store, transport, and utilise large volumes of chemicals, a proportion of which inevitably finds its way to the shallow sub-surface. In many cases, potentially polluting chemicals are applied directly to urban surfaces (e.g. as road salts, fertilizers and pesticides), are stored in the subsurface (e.g. gasoline tanks) or are released to the subsurface (e.g. septic systems). Because most of the basin's larger urban areas rely almost exclusively on lake-based supplies, very little attention is given to the accumulation of contaminants in shallow urban groundwaters and the serious risks they pose. Assessment of the problem is complicated by the widespread use of urban fill and a complex network of drains, pipes and tunnels that create “urban karst”, a shallow artificial aquifer, unique to urban settings, that exerts a major, yet often unpredictable influence on groundwater flow and contaminant transport. Management of ground water pollution, and its impact on the receiving Great Lakes, will require rigorous audits of all urban sources of contamination together with the development and calibration of groundwater flow and transport models that will enable the fate of urban pollutants to be reliably predicted even when groundwater is not used for supply.     

海河流域地下水系统脆弱性评价的探讨

海河流域地下水目前面临着严峻的生态与环境问题。结合海河流域具体情况,选择山前平原的石家庄和唐山、中部平原的沧州和衡水、东部滨海平原的天津等地作为5个典型区域进行具体研究。在采用DRASTIC方法对典型区域进行地下水脆弱性评价时,选取了地下水埋深、土壤有机质含量、含水层的渗透系数、含水层累计（沙层）厚、降雨灌溉等入渗补给率、地下水开采系数这6个参数作为评价指标,并以此指标体系为基础进行了脆弱性研究。结果表明,海河流域地下水各典型区的脆弱性指数均较高,海河流域地下水的脆弱性问题较为严重。要恢复和提高地下水系统的生态与环境功能,需采取6项对策措施。     

Optimal allocation of surface water in regional water management

Surface water is a scarce reource that is applied by various users for a variety of activities. The regulation of surface water use is an element of regional water management at various management levels. At each management level, the allocation of surface water supply capacity is a policy instrument. An optimization model has been formulated to support the evaluation of potential allocations at a particular management level. The model describes the allocation problem as a network, in which arcs represent waterways and nodes represent inlets and locations where there is a demand for surface water supply. The use of surface water for a specific activity at a specific node is referred to as an application, for example, for sprinkling, for use as cooling water, for dissolving effluent, and for conservation of environmental areas. The optimization model generates the optimal allocation of surface water and of surface water supply capacity. The operation of the model was demonstrated by a case study, where it was applied to maximize the expected revenues in agriculture (measured as value added).     

Exploring market-based environmental policy for groundwater management and ecosystem protection for the Great Lakes region: Lessons learned

The Great Lakes–St. Lawrence River Basin Water Resources Compact (the Compact) was created to protect future water supplies and aquatic ecosystems in the Great Lakes. The Compact requires the eight Great Lakes state to regulate, among other things, large withdrawals of groundwater and surface water so that they do not negatively affect stream flows and ecosystems within the Great Lakes Basin. Thus, the Compact raises the possibility of increased restrictions on groundwater withdrawals in many locations throughout the Great Lakes region. However, restricting withdrawals is likely to encounter opposition from water users when such restrictions are viewed as an infringement on existing water use rights and/or as negatively impacting local economic development. Such conflicts could hinder effective implementation of state and regional water policy. This paper explores the application of a market-based environmental management tool called “Conservation Credit Offsets Trading (CCOT)” that could facilitate allocation of groundwater withdrawals, and develops a framework for guiding the implementation of CCOT within the context of a groundwater permitting system. Using a watershed in southwestern Michigan, this study demonstrates how bio-physical information and input from various local stakeholders were combined to aid groundwater policy designed to achieve the objective of no net (adverse) impact on stream ecosystems. By allowing flexibility through trading of conservation credit offsets, this groundwater policy tool appears to be more politically acceptable than traditional, less flexible, regulations. The results and discussion provide useful lessons learned with relevance to other areas in the Great Lakes Basin.     

地表水与地下水的联合调蓄及其供水风险性分析

本文阐述了年调节水库与地下水联合调蓄的模拟分析方法,并通过对石佛寺水库地表水与地下水联合调蓄模拟计算,提出了石佛寺平原水库地表水与地下水联合调蓄的供水规模及其运行方式。建立风险分析模型,进行了供水系统的风险性分析。     

雷州半岛地表水与地下水联合利用浅析

分析了雷州半岛的水资源情况及其存在的工程性缺水严重,地下水超采导致的地面沉降、海水入侵,等水资源供需矛盾日益突出的问题。论述了地表水--地下水联合利用的必要性,探讨了雷州半岛地表水、地下水资源联合利用的潜力及措施。     

建设项目温排水对水环境影响分析初探

建设项目水资源论证分析工作需要科学、实用的数学模型进行退水对水环境的影响分析计算，当前相继立项建设的电厂、热电厂都将产生大量的温排水，其稀释扩散规律与普通污染物扩散规律有一定的相似性。本文通过实例，采用二维对流扩散模型分析探讨温排水对水环境的影响程度。     

Groundwater contributions to surface water in the Assiniboine Delta Aquifer (ADA): A water quantity and quality perspective

In the Lake Winnipeg Basin (LWB), at both basin and regional scales, there are currently gaps regarding the significance of groundwater as a mediator of nutrient and contaminant fluxes to Lake Winnipeg. During 2018, surface water and groundwater samples were collected from various locations across the largest sand and gravel aquifer (Assiniboine Delta Aquifer [ADA]; 3800 km²) in the LWB as well as from surface water courses flowing above this aquifer. The samples collected during spring and fall were analyzed for anions and cations as well as for a series of isotopic and geochemical tracers (e.g. water isotopes, carbon 14, artificial sweeteners, pesticides, etc.). The results reveal that groundwater and the small watercourses flowing above the ADA have a similar chemical composition, which is in contrast with the chemical composition of the main watercourse flowing above the aquifer (Assiniboine River [AR]). When corroborated with stream discharge measurements this indicates that groundwater plays a significant role at local scale in controlling both the flow and the chemical composition of the AR tributaries. Nitrate showed low to non-detectable concentrations in both groundwater and surface water. With respect to groundwater, this could be related to the reducing conditions in the deeper aquifer in conjunction with relatively large groundwater travel times of up to 2400 years.     

柘林大坝第二溢洪道泄洪运行安全分析

柘林大坝第二溢洪道泄洪闸结构稳定,位移和渗流运行性态正常,泄流能力满足原设计要求。但尾渠内人口稠密、房屋林立,一旦泄洪,如何保障尾渠内的人民生命财产安全是本工程泄洪运行需要重点关注的问题。因此,电厂必须与地方政府联动,制定出切实可行的防洪抢险应急预案,警钟长鸣、定期演练,以能在泄洪非常时期把损失降到最低。     

UF-RO组合工艺处理循环冷却排污水的研究

在电力循环冷却排污水回用系统中,采用UF-RO组合工艺对循环排污水进行去浊除盐.通过现场试验,考察了超滤在循环冷却排污水回用中作为反渗透预处理的可行性;在工程实践中确定了系统实际运行工艺参数并对运行成本进行了分析.该工艺为循环冷却排污水的再利用开辟了一条新途径,既节约了水资源,又减少了环境污染.     

欧洲流域水质模型在我国水功能区污染物入河量控制中的应用

我国实施的最严格水资源管理制度明确提出要确立水功能区限制纳污红线,从严核定水功能区纳污量,严格控制入河排污总量。介绍了使用欧洲流域水质模型(CC+PLAS)核定水功能区纳污能力和制定污染物入河总量控制方案,为落实水功能区限制纳污红线提供决策支持。此模型将我国计算纳污能力和污染物入河量控制的方法与欧洲用于流域综合规划的水质模型理念相结合,综合考虑影响河流水质的各种因素,对多种不同设计流量下的纳污能力进行核定,对不同污染入河量控制方案产生的水质效果进行测试,使污染入河量控制方案具有广泛的操作性和灵活性,推动水功能区纳污红线的有效落实。此模型同时为流域水资源保护规划工作提供一种方便科学的计算工具,为实现2015、2020、2030年水功能区达标率的目标提供有力支持。     

Status of the major aquaculture carps of China in the Laurentian Great Lakes Basin

There is concern of economic and environmental damage occuring if any of the four major aquacultured carp species of China, black carp Mylopharyngodon piceus, bighead carp Hypophthalmichthys nobilis, silver carp H. molitrix, or grass carp Ctenopharyngodon idella, were to establish in the Laurentian Great Lakes. All four are reproducing in the Mississippi River Basin. We review the status of these fishes in relation to the Great Lakes and their proximity to pathways into the Great Lakes, based on captures and collections of eggs and larvae. No black carp have been captured in the Great Lakes Basin. One silver carp and one bighead carp were captured within the Chicago Area Waterway System, on the Great Lakes side of electric barriers designed to keep carp from entering the Great Lakes from the greater Mississippi River Basin. Three bighead carp were captured in Lake Erie, none later than the year 2000. By December 2019, at least 650 grass carps had been captured in the Great Lakes Basin, most in western Lake Erie, but none in Lake Superior. Grass carp reproduction has been documented in the Sandusky and Maumee rivers in Ohio, tributaries of Lake Erie. We also discuss environmental DNA (eDNA) results as an early detection and monitoring tool for bighead and silver carps. Detection of eDNA does not necessarily indicate presence of live fish, but bigheaded carp eDNA has been detected on the Great Lakes side of the barriers and in a small proportion of samples from the western basin of Lake Erie.     

Application of a glyphosate-based herbicide to Phragmites australis: Impact on groundwater and near-shore lake water at a beach on Georgian Bay

During the past decade, the invasive Phragmites australis (common reed) has established itself along beaches of the Great Lakes, causing detrimental impacts to both the natural ecological integrity of the shoreline and the recreational value of beaches. The herbicide Roundup®, containing the active ingredient glyphosate, was applied to Phragmites along a beach on the southern shore of Georgian Bay, Canada, to eradicate the Phragmites which was destroying the natural beach ecosystem. Groundwater and lake water were tested to determine if glyphosate enters the groundwater and lake at the beach and how long glyphosate will persist. Two days after application, the geometric mean concentration of glyphosate in the groundwater below the Phragmites was 0.060 μg/L with a maximum of 12.50 μg/L. Concentrations rapidly declined over the next two to three weeks to below minimum detection limits (< 0.020 μg/L). Glyphosate was also detected in the nearshore lake water with concentrations peaking at a geometric mean of 0.14 μg/L one week after application, and declining to 0.039 μg/L four weeks after application. Concentrations of glyphosate never exceeded the Canadian water quality guideline for the protection of aquatic life (65 μg/L) in either the groundwater or lake water. An approximate half-life for the dissipation of glyphosate by degradation and dilution/flushing as groundwater flows toward the lake, assuming a first order kinetic reaction, yielded a half-life of 3.5 during the 4 weeks after the herbicide was applied. The application of Roundup® resulted in an 90% reduction in the size of the stand of Phragmites.     

Relative importance of macrophyte community versus water quality variables for predicting fish assemblages in coastal wetlands of the Laurentian Great Lakes

Fish have been shown to be sensitive indicators of environmental quality in Great Lakes coastal wetlands. Fish composition also reflects aquatic macrophyte communities, which provide them with critical habitat. Although investigators have shown that the relationship between water quality and fish community structure can be used to indicate wetland health, we speculate that this relationship is a result of the stronger, more direct relationship between water quality and macrophytes, together with the ensuing interconnection between macrophyte and fish assemblages. In this study, we use data collected from 115 Great Lakes coastal marshes to test the hypothesis that plants are better predictors of fish species composition than is water quality. First we use canonical correspondence analysis (CCA) to conduct an ordination of the fish community constrained by water quality parameters. We then use co-correspondence analysis (COCA) to conduct a direct ordination of the fish community with the plant community data. By comparing the statistic ‘percent fit,’ which refers to the cumulative percentage variance of the species data, we show that plants are consistently better predictors of the fish community than are water quality variables in three separate trials: all wetlands in the Great Lakes basin (whole: 21.2% vs 14.0%; n = 60), all wetlands in Lakes Huron and Superior (Upper: 20.3% vs 18.8%; n =  32), and all wetlands in Georgian Bay and the North Channel (Georgian Bay: 18% vs 17%; n =  70). This is the largest study to directly examine plant–fish interactions in wetlands of the Great Lakes basin.