Predicting the oscillating bi-directional exchange flow in the Straits of Mackinac

The Straits of Mackinac are a unique feature that connects Lake Michigan and Lake Huron into a single hydraulically linked system. With currents of up to 1 m/s and oscillating volumetric transport up to 80,000 m³/s, they play an important role in water quality, contaminant transport, navigation, and ecological processes. We present the first three-dimensional hydrodynamic model of the combined Lake Michigan–Huron, including the Straits of Mackinac at high-resolution, that is able to simulate the three dimensional structure of the oscillating flows at the Straits. In comparison with individual lake models for Michigan and Huron (no connection at the Straits), we are able to isolate the effects of the bi-lake oscillation and have found that although the oscillation (Helmholtz mode) is the dominant forcing mechanism, the flow can be modulated when atmospheric systems are in-phase with water level fluctuations. Furthermore, the area of influence of the Straits is found to extend up to 70 km into each lake, underscoring the need for realistic predictions within the Straits. For the first time, this combined-lake hydrodynamic model provides the capability to investigate and accurately predict flow at the Straits of Mackinac and its effect on Lake Michigan and Huron. This model forms the basis for the next generation of real-time hydrodynamic models being developed for the Great Lakes Coastal Forecasting System, a suite of models designed by the National Oceanic and Atmospheric Administration Great Lakes Environmental Research Laboratory (NOAA/GLERL) that predict hydrodynamic conditions such as currents, temperatures, and water levels in three dimensions.     

Economic damages from a worst-case oil spill in the Straits of Mackinac

This paper presents research on the economic damages from a hypothetical worst-case oil spill at the Straits of Mackinac between Lakes Huron and Michigan. This spill could occur because the Enbridge Line 5 oil pipeline traverses the Straits between Michigan's Upper and Lower Peninsula. We quantify potential economic damages to outdoor recreation, commercial fishing, shipping, residential properties, and energy and water supplies. Damages are estimated for two spill scenarios occurring at the onset of the summer tourism season with extensive shoreline oiling. Using evidence from past spills, economic damages would last for between one and two years and would affect locations on the periphery of the spill area, depending on the activity. We project the loss from the worst-case scenario would be at least $1.3 billion.     

Notes on the Benthic Alga Dichotomosiphon from the Straits of Mackinac Area of Lakes Michigan and Huron

During the summers of 1955–1956 the author was engaged in a sampling program to describe the distribution of the benthos and bottom sediments in the Straits of Mackinac area of the Great Lakes. The elusive benthic alga Dichotomosiphon tuberosus was identified from 17 of more than 690 bottom samples that were collected. Since there has been virtually no mention of this species in the Great Lakes literature since the time of collection, it is appropriate to report this matter at this time. This alga was distributed generally in the South Channel between Bois Blanc Island and the northern Michigan shoreline, and between the depths of 3.4 and 17.1 m. Most of the sediments associated with this species were sand with pebbles, low in clay, and with 5 to 10% silt.     

水库下游输水隧洞出口河段水沙分布研究

以辽宁大伙房输水隧洞出口河段为研究对象,基于实测资料,利用平面二维水流泥沙数学模型,计算了大伙房输水隧洞出口河段内水流和泥沙冲淤的分布形态,预测了出口河段30年内的水沙运动趋势,为工程实践提供了参考。     

Limnological Sampling Intensity in Lake St. Clair in Relation to Distribution of Water Masses

Cluster analyses of physical and chemical data from Lake St. Clair identified two distinct water masses, a northwestern mass consisting primarily of Lake Huron water flowing from the main channels of the St. Clair River, and a southeastern mass of more stable water enriched by nutrient loadings from Ontario tributaries and shoreline urban development. The margins of the masses shifted according to wind direction and speed but the overall discreteness of the distribution was maintained. Comparison of station data to water mass means indicated that one index station in each mass would provide a more-than-adequate estimate of water quality within each water mass. Data collected at a single index station over a five-year period were representative of each water mass and more than adequate for trend analysis. Multivariate analyses of environmental data collected on a grid basis demonstrated that uniformity of water masses permits a reduction in sampling intensity.     

井库流量补偿式配水系统及其配水方式研究

分析城市多水源供水工程中配水系统不同组成方式存在的不足,通过改进“供水水库＋调节水 库”联合供水方式,创新地提出了一种井库流量补偿式配水系统。配水系统在调节水库库岸增设配水 井,上游供水水库输水管道接入配水井后再向下游水厂供水,配水井设连通闸与调节水库连通,配水井 与调节水库之间供水流量可相互补偿,在常规的供水水库单独供水、调节水库单独供水、供水水库和调 节水库联合供水配水方式基础上,还具有供水水库向调节水库和下游水厂同时供水的功能。配水井是 井库流量补偿调节的中枢,配水井的布置以及体型对系统调节的稳定性及效率影响巨大,结合千岛湖配 水工程水工模型试验成果,提出了一种岸坝组合碗式配水井结构。     

水权理论与南水北调工程水权分配

南水北调是一项跨流域、跨省市的远距离调水工程，由于沿线各省（市）的自然地理、人口、资源、社会、经济等状况各不相同，因此必然存在流域、城市之间用水矛盾和利益协调问题。通过对国内外水权现状进行研究，根据水权基本理论，从我国社会主义市场经济体制、水资源状况和南水北调工程实际出发，提出了南水北调工程水权分配的基本思路、原则和程序。     

Some Measurements of Near Surface Turbulence in the Depth Direction and Some Phytoplankton Distribution Implications

Micro turbulence measurements were made near the surface in Hamilton and Toronto harbours using a hot film anemometer during stratified and well-mixed conditions. The turbulent structure in the two harbors was found to be different. The depth length scales were estimated to be 3.7 to 5.7 and 10.8 to 20 cm in the stratified and well-mixed cases respectively. The depth dispersion coefficients were estimated to be 4.8 to 8.6 cm² s^?1 and 22.7 to 44 cm² s^?1 in the stratified and well-mixed cases respectively. Depth phytoplankton patchiness did not exist in the well-mixed case. The mean depth patch size for greens and Cryptomonads showed some relationship with turbulence integral scales and the most predominant periodicities. Greens were a larger portion of the biomass when the length and time scales were small, while diatoms were more prevalent with larger length and time scales.     

水槽近底流速分布与推移质输移特性研究

通过开展水槽试验,利用ADV测速及高速摄像技术采集了近壁区的流速及紊动特征值,分条带计量了推移质输移情况。通过对比横向密布测点的流速结构差异,剖析了近底流速分布的变化特点与两侧的流速结构变异。基于输沙分条带量化观测模式,对推移质输移的空间横向分布特性进行了分析。结果表明:(1)近底流速的相对脉动强度呈现中间区域最大并向两侧递减的趋势,在临近侧壁处有突变波动现象,这与近底流速的横向分布在侧壁附近的突变特点相互对应;(2)推移质输移在横向分布上不均匀,整体呈从中间向两侧逐渐递减的趋势,80%的区域基本完成了断面的总输沙量,近侧壁区域输沙受边壁影响较明显;(3)近底流速横向分布、近底水流脉动强度与相对输沙强度的横向分布存在响应协同性。     

The Distribution of Diatoms Near a Thermal Bar in Lake Baikal

Studies of the spatial distribution of suspended matter and of diatoms across a thermal bar in Lake Baikal revealed that waters sinking at the thermal bar front (2 km off-shore) move to the bottom along the underwater slope, and may be traced to a depth of at least 700 m, 5 km off-shore. The distributions of 11 diatom species across the thermal bar were significantly different, reflecting their different ecological requirements. Maximum concentrations of Asterionella formosa, Nitzschia acicularis, Aulacoseira islandica occur near the shore. The distribution of Stephanodiscus hantzschii, a species characteristic of the Selenga River, suggests that riverine waters penetrate far into the lake along its eastern shore. Another species typical of the Selenga River, Stephanodiscus minutulus, was found both near the shore, and in the surface waters of the open lake. Endemic spring baikalian diatoms Aulacoseira baicalensis and Cyclotella baicalensis were found at highest concentrations in the deep waters far off-shore, beyond the thermal bar. Another endemic diatom, the autumn species Cyclotella minuta was evenly distributed over the open lake at all depths. The data obtained shed new light on the dynamics of water masses near thermal bars, and on the ecology of the diatom species studied.     

Water Distribution Scenarios in the Mexican Valley

Mexican Valley is one of the Mexico’s most critical areas of water supply, the groundwater resources are overexploited at a rate of 100% or more, generating ground sinking up to 0.4 cm/year in some areas. Water shortage in this area is already at an alarmingly critical level. The situation is expected to worsen due to increasing domestic, industrial and agricultural water demands. The limited water resources, the competing users and the combination of several water sources with different qualities require the development of an adequate water distribution system. The objective of this work is to generate a water distribution model as a three-person linear game in which the users are the players, the supplied amounts from five sources are the strategies, and the total water supplies are the payoffs. Since the available water supplies are lower than the total demands from the users, a tradeoff has to be determined. The nonsymmetric Nash bargaining method is used, which requires the solution of a special optimization problem with nonlinear objective function and linear constraints. For all water distribution scenarios there is no water distribution strategy that satisfies the domestic demand with the current system. Therefore investments and further developments are needed in combination with more efficient water usage by the three sectors in the near future to secure the satisfaction of domestic users. A market driven water pricing policy also would give an incentive to the users for more efficient usage of water.     

黄河三角洲附近海域悬浮泥沙浓度估算

基于黄河口附近海域水体悬浮泥沙浓度及光谱信息同步测量数据,设计了使用MODIS Band1波段反射率进行悬浮泥沙浓度定量反演的模型.以MODIS产品MOD09GQ陆地反射率数据为数据源,进行了黄河三角洲附近海域悬浮泥沙浓度反演,获得了2009年夏季黄河入海口悬浮泥沙浓度分布图,结果表明:悬浮泥沙浓度分布的基本趋势是由岸向海逐渐降低,但在黄河入海口南北两侧浓度梯度表现出较大差异;浓度大于300 mg/L的悬浮泥沙主要分布在清水沟流路以南的莱州湾西岸,而黄河清8汊以北区域仅在特定潮流及天气情况下在河口以外区域有较宽分布;浓度为10 ～ 300mg/L的中、低浓度悬浮泥沙主要分布在入海口南侧莱州湾中部海域、高浓度悬浮泥沙分布区以外;浓度小于10 mg/L的极低浓度悬浮泥沙主要分布在上述区域之外远离岸线的地区.     

调水工程水权计算方法研究

根据水权的基本理论，结合调水工程的特点，提出分时段水权的概念。在分析影响水权分配的主要因素后．把调水水权分成用户投资获取的水权和国家水权再分配两部分，概念清晰，易被接受，在此基础上建立了调水水权再分配计算的数学模型，利用混沌优化方法进行优化计算，求解精度和可靠性较高，最后给出了计算方法的应用示例．获得了较为合理的结果。     

黄河中游近期水土保持工作的两个重点

要想快速减少入黄泥沙，黄河中游近期水土保持应注意两个重点，一个是治理的区域重点，即7．86万km^2的多沙粗沙区治理，另一个是措施重点，即沟道坝系建设，坝库工程不仅有直接拦泥作用，还有明显的间接减蚀作用，从岔巴沟资料分析看,坝库间接减蚀量占天然输沙量的6．0％－34．8％，平均为20．7％。     

水资源管理系统区间数属性联系贴近度评价

针对水资源管理系统区间数多属性决策评价问题,借鉴集对分析理论,采用区间数属性联系贴近度评价方法,通过引进系统范数的概念进行属性区间数指标决策矩阵规范化处理,将区间数决策矩阵转化为联系数加权决策矩阵,获得水资源管理系统方案评价的计算方法,并通过实例对该方法的有效性和实用性进行验证,取得了较为满意的结果。     

Distribution and Characterization of PCBs in Lake Michigan Water

Polychlorinated biphenyls (PCBs) were measured in the water column of Lake Michigan at 28 stations. Distributions between dissolved and particulate phases were used to evaluate the partitioning behavior of PCBs. The average PCB concentration in Lake Michigan was 1.8 ng/L, corresponding to a total PCB burden of 8,900 kg. The average PCB concentration was significantly lower in open lake (1.2 ng/L) than in nearshore zone samples (3.2 ng/L). Concentrations in Green Bay were elevated compared to the rest of the lake. Variations in concentration with depth were small. The average log of the water-particle partition coefficient (Kp) was 5.9. Little dependence of Kp on particulate organic carbon was observed. A relationship was found between log Kp and log SPM (suspended particulate matter) concentration, perhaps reflecting association of a non-filterable fraction of the SPM with the aqueous phase. Selected PCB congener Kp and Koc (Kp × organic carbon weight-fraction) values were measured and related to congener Kow (octanol-water partition coefficient), yielding the predictive relationship log Koc = 4.2 + 0.34 log Kow. Congener log Kp values are predicted to range from 4.8 to 6.1, indicating that congener fates in the water column differ and are partly controlled by their physical chemical properties.     

广西城市供水水源的流域分布与水质特征

广西城市供水水源在珠江流域西江水系中呈流域分布的特点,水源的特征性指标与自然背景特征密切相关。通过对水源的特征性指标的全年表现和不同水系与流域的比较研究,发现不同水系和流域水源的水质特征有共同点也呈现差异性。各水系和流域的水硬度有明显的第次差别。研究结果表明以西江水系为主的地表水是广西城市供水理想的水源,水质特征对后续的水处理工艺非常有利。     

Parameter Estimation in Water Distribution Networks

Estimation of pipe roughness coefficients is an important task to be carried out before any water distribution network model is used for online applications such as monitoring and control. In this study, a combined state and parameter estimation model for water distribution networks is presented. Typically, estimation of roughness coefficient for each individual pipe is not possible due to non-availability of sufficient number of measurements. In order to address this problem, a formal procedure based on K-means clustering algorithm is proposed for grouping the pipes which are likely to have the same roughness characteristics. Also, graph-theoretic concepts are used to reduce the dimensionality of the problem and thereby achieve significant computational efficiency. The performance of the proposed model is demonstrated on a realistic urban water distribution network.     

改善城市供水管网水质的实践与探讨

嘉兴水司出厂水流经管网以后 ,浊度、色度、总铁有时升高明显 ,主要原因为出厂水稳定性较差 ,大部分管网老化严重。针对这些问题采取了用新净水工艺 ,提高出厂水水质 ,取消屋顶水箱 ,加快旧的输配水管网改造等应对措施     

Water Distribution Control Model in the Yellow River Basin

Abstract

This study develops a water distribution control model to manage and operate a multipurpose, multi-reservoir system in the Yellow River Basin. The aim is to make the best use of limited water resources and to coordinate different uses. The overall control task is made up of two processes. An initial distribution scheme is obtained through a simulation model first, then the scheme's output suggestions are adjusted by a harmony index which is considered as a feedback regulator, and the order parameter in synergetic theory is applied in this regulator. Control criteria and a subsequent application of the method are presented. Case studies indicate that the proposed control process facilitates quick and efficient distribution control and can provide both theoretical and technical support for sustainable water resources development in the Yellow River in China.