Optimal Management of Coastal Aquifers Using Linked Simulation Optimization Approach

Saltwater intrusion management models can be used to derive optimal and efficient management strategies for controlling saltwater intrusion in coastal aquifers. To obtain physically meaningful optimal management strategies, the physical processes involved need to be simulated while deriving the management strategies. The flow and transport processes involved in coastal aquifers are difficult to simulate especially when the density-dependent flow and transport processes need to be modeled. Incorporation of this simulation model within an optimization-based management model is very complex and difficult. However, as an alternative, it is possible to link a simulation model externally with an optimization-based management model. The GA-based optimization approach is especially suitable for externally linking the numerical simulation model within the optimization model. Further efficiency in computational procedure can be achieved for such a linked model, if the simulation process can be simplified by approximation, as very large number of iterations between the optimization and simulation model is generally necessary to evolve an optimal management strategy. A possible approach for approximating the simulation model is to use a trained Artificial Neural Network (ANN) as the approximate simulator. Therefore, an ANN model is trained as an approximator of the three dimensional density-dependent flow and transport processes in a coastal aquifer. A linked simulation – optimization model is then developed to link the trained ANN with the GA-based optimization model for solving saltwater management problems. The performance of the developed optimization model is evaluated using an illustrative study area. The evaluation results show the potential applicability of the developed methodology using a GA- and ANN-based linked optimization – simulation model for optimal management of coastal aquifer.     

基于数据同化校正参数的河流磷迁移估计研究

通过磷迁移数学模型合理估计磷在河流中的时空分布,对防治水体富营养化,抑制水华暴发具有重要的科学和工程意义。数据同化方法可以将模型和观测两种研究手段有机地结合起来,将观测数据融入模型,优化模型状态变量,校正模型参数,进而提高数学模型的模拟预报精度,并依托物联网技术将传统数学模型发展为实时数学模型。本文将粒子滤波数据同化算法引入到水动力-泥沙-磷迁移模型中,以实测的断面磷含量作为观测数据,在观测时刻优化磷含量估计结果,同时校正模型参数磷相平衡分配系数Kd,构建了水动力-泥沙-磷迁移模型同化系统。将其应用于长江上游寸滩至坝前河段的计算结果表明,所构建的同化系统在真实的河流中计算效果良好,可以有效地优化更新状态变量各相磷含量浓度,并反演出模型参数Kd随水沙水环境条件变化的动态变化过程,同化之后模型模拟预报磷输移过程的精度显著提升,为水质实时模型打下基础。     

城市供水管网瞬态水力模型的建立和应用

以上海市北自来水公司供水管网为例,阐述了在"稳态模型"的基础上自动建立"瞬态模型"的系统方法:首先,根据管网情况对瞬变流需求分析进行权值计算;其次,根据统计模型确定计算范围并对管网进行自动标志;然后确定边界条件和其他系统参数,并用特征线法对"瞬态模型"进行计算;最后根据现场实测数据对模型进行校验.与传统方法相比较,该方法在建立供水管网动态水力模型的过程中将"稳态模型"和"瞬态模型"有机地结合起来,拓展了其应用的范围,能有效地帮助管理者预防管网事故的发生.     

A numerical tool to integrate biophysical diversity of a large regulated river: hydrobiogeochemical bases. The case of the Garonne River (France)

This article presents the bases of a hydrobiogeochemical model of the Garonne River (southwest France) which has been developed to integrate physical and biological processes during summer low‐water periods. The physical part of this model is composed of a one‐dimensional unsteady hydrodynamic model, allowing the resolution of the Saint‐Venant equations, and a transport model which simulates downstream changes in solute concentrations. Biogeochemical processes are considered through the definition of functional compartments which make up the channel bed. These different compartments are defined both by the organisms involved in the solute transformation processes and by the physical and hydraulic characteristics of their habitat. Integration of these functional compartments within the model required investigations at different scales. The scale at which biological processes take place ranges from millimetres to metres. The scale of a reach, at which organization of the functional compartments along the river can be linked to hydrodynamic and morphological characteristics, ranges from 500 m to several kilometres. The regional scale is that at which homogeneous reaches can be integrated. A feedback between numerical results and field experiments has allowed improvements to in situ measurement to increase modelling accuracy. For example, the model allows estimation of variables, such as fluxes, that are difficult to measure in situ. The developed model can integrate various functional compartments and their biogeochemical functioning. Two application examples, focused on dissolved inorganic nitrogen, are presented in order to illustrate the numerical tool functioning: integration of equations on nitrification processes in the water body, and integration of consumption/production terms on epilithic biofilm resulting from in situ experimental mean values. The model we have developed constitutes a promising analytical tool that will be able to integrate previous and future studies. Copyright © 2002 John Wiley & Sons, Ltd.     

基于正交试验法的河岸带水热耦合模型敏感参数识别

为了研究河岸带水热耦合模型参数对温度及侧向潜流交换速率有限元计算结果的影响,基于正交试验法,对影响河岸带温度T和侧向潜流交换速率|v_x|的水热耦合模型进行敏感参数识别。结果表明：孔隙率n对河岸带水热耦合模型温度输出结果的影响最大;对于侧向潜流交换速率,水力传导率k_s的影响最大,而其他参数的影响均较小。因此,在进行河岸带水热耦合模型参数反演或校正时,应将模型中的孔隙率和水力传导率作为重点参数,而敏感程度低的参数可通过工程类比的方法进行确定,这样既可以保证计算精度,又可以提高计算效率。     

Application of a Hydrologic Model Considering Rainwater Storage to Analyze Storm-induced Landslides in a Forest Catchment

In this study, a conceptual hydrologic model was applied for the analysis of storm-induced landslides, which were affected by typhoons in 2004, in the forest catchments of Ehime Prefecture, Japan. Through the model, hydrologic conditions such as rainfall intensity, rainwater storage, and soil moisture behavior in 2004 were obtained and compared with other 19 years (1985 ∼ 2003). Furthermore, the relationship between landslide occurrence and hydrologic phenomena in the catchments were assessed. Results of this study indicated that soil moisture, excess rainfall storage combined with rainfall intensity, and its duration in the forest were the key elements for the occurrence of landslides. The hydrologic model in this study was able to represent hydrologic phenomena reasonably and it can be used for the estimation of discharge, soil moisture content, and water storage in catchments. The concept of this model is available to be applied in other areas and can be expected to provide important information on soil moisture behavior for forecasting and preventing landslide disasters.     

考虑偶应力影响的双组节理岩体等效模型

考虑到岩体中节理存在的影响,针对具有两组斜交节理的岩体,通过对代表单元的分析,得到了基于一般 Cosserat 介质理论的等效模型,该模型可以退化到岩体具有两组正交节理或一组节理的情形。将上述模型以自编程序实现,对节理岩体沉降进行了数值模拟,同时采用增设节理单元法进行了对比分析,两者具有较好的一致性,最后讨论了两组节理不同斜交角度的影响,计算结果表明等效模型合理有效。     

一二维联解潮流数学模型在防洪评价中的应用

针对单纯使用一维或二维数学模型难以准确高效模拟大型涉水工程对水域影响的问题,通过利用一、二维联解潮流数学模型,在珠江口某港区码头工程附近使用二维模型,对该区域流场和流速变化范围进行模拟,其余水域采用一维模型模拟。结果表明,工程对珠江东四口门及工程周边水域水位、流速、河道潮量及分流比、潮排、潮灌、排涝等影响不大。结论认为,一、二维数学模型联解计算可以用于大型工程,尤其是海域内大型工程的防洪评价计算,并能够得出较为可靠的计算结果。     

Multicriteria Evaluation of Flood Control Measures: The Case of Ribeira do Livramento

This paper describes the multicriteria process used to evaluate flood control options for the catchment of Livramento creek in the peninsula of Setúbal, in Portugal. In the structuring phase, the environmental, social, and technical dimensions were identified. The MACBETH approach – Measuring Attractiveness by a Categorical Based Evaluation Technique – was then used to construct a quantitative evaluation model based on qualitative value judgments formulated by a group of experts from different technical and scientific fields. The model enabled the overall benefit associated with each option to be appraised, and extensive sensitivity analyses to be performed.     

Initial model choice: An operational comparison of stochastic streamflow models for drought

The performance of five stochastic models for generating annual streamflow sequences is evaluated based on applications to four Utah streams. Model performance is evaluated in terms of preservation of annual persistence statistics; cost and ease of model use; magnitude of the economic regret associated with drought-related agricultural losses; and comparison of reservoir capacity and critical drought design parameters. The ARMA-Markov and ARMA models are judged to be best overall in terms of preserving short- and long-term persistence. The broken line model is judged to be best in terms of minimizing economic regret. An initial model choice procedure is proposed.     

大型浮体闸水工模型试验方法

根据浮体闸水动力量测要素的相似要求,详细分析水工模型试验所遵循的相似准则和设计试验方法,提出了双模型试验方法。基于工程安全和减小误差的原则,得出如下结论:浮体闸水力模型应按重力相似准则设计,以保证模型水流处于紊流阻力平方区,并且使模型浮体闸各部分质量分布与原型相似,结构振动模型在线应变比尺接近1的情况下可以独立地选取长度、弹性模量和密度比尺。简单介绍了模型浮体闸控制量测试验装置设计及测力传感器的布置方式。     

Response of Hydrodynamics and Water-quality Conditions to Climate Change in a Shallow Lake

Lake water resources operation and water quality management come up with higher challenges due to climate change. The frequency and intensity of extreme hydrological events are increasing under global warming, which may directly lead to more uncertainty and complexity for hydrodynamic and water-quality conditions in large shallow lake. However, studies about effects of climate change on lake hydrodynamic and water-quality conditions are not enough. Thus, a coupled model is es-tablished to investigate the potential responses of lake water level, flow field and pollutant migra-tion to the changing climatic factors. The results imply that water flow capacity and self-purification in the Hongze Lake can be improved by west, northwest, north, south and southeast winds indi-cating wind filed change has a great effect on the hydrodynamic and water-quality conditions in large shallow lake. It is further observed that both hydrodynamics and water quality are more sensitive to rainfall change than to temperature change; compared to the effect from temperature and rainfall, the effect from wind field appear to be more pronounced. Moreover, the results verify the feasibility of coupling basin hydrological model with lake hydrodynamic and water quality model. To the best of knowledge, the coupled model should not be used until independent calibra-tions and verifications for hydrodynamics and water quality modeling, the hydrological model and the coupled model.

     

AGNPS-based Assessment of the Impact of BMPs on Nitrate-Nitrogen Discharging into an Illinois Water Supply Lake

Abstract

The Agricultural Non-Point-Source Pollution (AGNPS) model was used to simulate storm-generated rainfall-runoff and distribution of nitrate-nitrogen (nitrate-N) concentration in the Upper Sangamon River basin draining into Lake Decatur in Decatur, Illinois. This water supply reservoir for the city of Decatur receives water from the 2,400-square-kilometer Lake Decatur agricultural watershed and has high nitrate-N concentrations periodically exceeding the 10 milligram per liter drinking water standard of the U.S. and Illinois Environmental Protection Agencies (USEPA and IEPA). Using monitored and estimated data, the model was calibrated and validated to predict closely-observed runoff volumes and nitrate-N concentrations. Sensitive model parameters were identified. The calibrated model was used to evaluate the effects of different agricultural and watershed management practices (BMPs) for reducing nitrate-N discharge into the lake. Model parameters were identified to represent the BMPs. Model results showed variations of nitrate-N discharge into the lake with respect to different BMPs and BMP applications at different areas of the watershed. The model was found useful in the preliminary evaluations of the BMPs in the Lake Decatur watershed for reducing nitrate-N discharge into the lake. The BMP evaluation approach and the results may be useful to users of the AGNPS model and other non-point-source pollution models. Model limitations must be kept in mind in interpreting the results from this empirically-based model and in using them to solve practical problems.     

改进的 GM（1，1）模型在工业需水量预测中的应用

灰色系统模型在贫信息、小样本的非线性系统建模中具有明显优势,适合对时间序列较短时的需水量进行预测。该文针对基本灰色预测模型背景值构造不合理及未充分利用新信息的缺点,采用重构背景值和等维递补原理对基本GM（1,1）模型进行改进,并利用改进模型对惠州市工业需水量进行拟合和预测,结果表明,改进模型预测精度更高,可作为城市需水量预测的一种方法。     

基于WPAPP模型的水土保持综合效益研究

鉴于传统的投影寻踪模型(PP)处理高维非线性数据很难达到良好的效果,引入生物群体智能算法中的狼群算法对PP模型进行优化,以提高投影寻踪模型的精准度。以生态效益和社会效益为准则层建立水土保持综合效益评价指标体系,并运用定量分析原理提出了水土保持综合效益的5类分级标准。将优化模型运用到湖北省郧西县3个时间段的水土保持综合效益研究中,分析结果与当地实际情况十分吻合,表明所建立的指标体系和优化模型比较合理,评价方法可行,不失为水土保持综合效益的研究提供了一类新的思路与方法。     

Evaluation of Reference Crop Evapotranspiration Equations in Various Climates

Evapotranspiration is one of the most important elements for quantifying available water since it generally constitutes the largest component of the terrestrial water cycle. This study evaluated four models (Makkink, Turc, Priestley–Taylor and Hargreaves) commonly used to estimate monthly reference crop evapotranspiration (ET_o) values. The main aim of this study was to determine the model used to estimate ET_o with small data requirements and high accuracy for twelve synoptic stations in four climates of Iran. The results showed that the Turc model was the best suited model in estimating ET_o for cold humid and arid climates. The Hargreaves model turned out to be the most precise model under warm humid and semi-arid climatic conditions. In contrast, the Makkink model presented the poorest estimates in all of the climates exception for cold humid environment. In cold humid climate, the Hargreaves model was the least accurate model in estimating ET_o. In general, the results obtained from this study revealed very clearly that the Makkink and Priestley–Taylor models estimated ET_o values less accurately than Turc and Hargreaves models for the all climates.     

基于MIKE模型的水华应急处理情景分析

基于MIKE模型的基础理论,建立了九龙江河段的水动力模型和水质模型,通过情景设计来分析水华应急处理方案的效果。分析结果显示:(1)水电开发降低了河道流速,特别是回水河段流速;(2)为满足抑制藻类生长的流速要求,需要增加目前的电站最小下泄流量;(3)当削减入河污染物排放时,河道污染物浓度降低,面源污染影响大于点源污染影响;(4)增加电站下泄流量和削减入河污染物可抑制水华发展。     

Relative humidity based model for estimation of reference evapotranspiration for western plateau and hills region of India

As an important constituent of hydrological cycle, estimation of Reference Evapotranspiration (ET_o) is essential for planning of projects related to water resources. This article compares the results obtained from the available pan evaporation based equations to estimate ET_o from pan evaporation (E_p) and proposes a new simplified methodology for estimation of ET_o, which needs only the data of relative humidity (H). The resulting model is based upon the collected meteorological data of a selected study area i.e. Nagpur District in Maharashtra State, which lies in western plateau and hills region of India. In the proposed methodology, E_p rates are adjusted to the values expected for 50 % relative humidity. Then, the relationship between ET_o and the adjusted E_p is established. The validation of the proposed new model has been carried out by comparing its results with the results obtained by the pan evaporation method, for the study area as well as for the data set of another area. This new model is found to be reasonably accurate for estimation of reference evapotranspiration for the study area and as such, is expected to be applicable to the river basins located in the regions having climatic conditions similar to that of the study area. Although, if the conditions are different then another site specific model can be developed by adopting the methodology proposed in this article.     

城市供水绩效的数据包络分析

在分析目前我国城市供水现状的基础上，阐述了供水绩效评价的重要性。介绍了数据包络分析(Data Envelopment Analysis，简称DEA)中C²R模型的基本概念，提出了使用Matlab求解此模型的具体步骤，建立了我国30个省市城市供水投入产出的C²R模型并对其进行了求解。实例的计算结果反映了目前我国城市供水的绩效水平，为城市供水绩效的分析评价找到了适用的定量化方法。