Design of Infiltrating Basin by Soil Storage and Conveyance Capacities

Abstract

Design of storm water storage basins must take both surface infiltrating flow and subsurface seepage flow into consideration. Standing water can result from the condition that the subsurface seepage capacity is less than the surface infiltrating capacity or the basin storage volume exceeds the soil pore volume underneath the basin. To avoid a prolonged draining operation, an infiltrating basin must be designed under the constraints of the soil pore storage capacity before saturation and the soil conveyance capacity after saturation. In this study, the potential flow model is developed to estimate the soil pore storage volume underneath the basin and to predict the conveyance capacity through the saturated soil medium between the basin and the local groundwater table. The potential flow model for infiltrating water flow provides a quantifiable basis to define the soil constraints and to compare various alternatives at the basin site.     

An Analysis of Future Water Policies in Jordan Using Decision Support Systems

Despite looming water shortages in Jordan, the country lacks a coherent water policy and has no recognized institutional mechan ism to create one. D urin g the last 30 years, this critical problem has largely been addressed by physical infrastructu re developm ent in the public sector and grou ndwater exploitation in the private. These efforts are not meeting the increasing dem ands of all competing sectors. This paper analyses possible future water policies in Jordan using decision support system s. An analytical hierarchy process is used to break policies in to compon ent parts, then synthesize and an alyse them in the context of constraints and scenarios in Jordan for the year 2010. The paper argues that Jordan mu st give priority to the efficient m anagement of water resources at the regional level. This includes institutional restructuring, new water pricing strategies, importation of water, and water desalination.     

Partially and Fully Constrained Ant Algorithms for the Optimal Solution of Large Scale Reservoir Operation Problems

This paper presents a constrained formulation of the ant colony optimization algorithm (ACOA) for the optimization of large scale reservoir operation problems. ACO algorithms enjoy a unique feature namely incremental solution building capability. In ACO algorithms, each ant is required to make a decision at some points of the search space called decision points. If the constraints of the problem are of explicit type, then ants may be forced to satisfy the constraints when making decisions. This could be done via the provision of a tabu list for each ant at each decision point of the problem. This is very useful when attempting large scale optimization problem as it would lead to a considerable reduction of the search space size. Two different formulations namely partially constrained and fully constrained version of the proposed method are outlined here using Max-Min Ant System for the solution of reservoir operation problems. Two cases of simple and hydropower reservoir operation problems are considered with the storage volumes taken as the decision variables of the problems. In the partially constrained version of the algorithm, knowing the value of the storage volume at an arbitrary decision point, the continuity equation is used to provide a tabu list for the feasible options at the next decision point. The tabu list is designed such that commonly used box constraints for the release and storage volumes are simultaneously satisfied. In the second and fully constrained algorithm, the box constraints of storage volumes at each period are modified prior to the main calculation such that ants will not have any chance of making infeasible decision in the search process. The proposed methods are used to optimally solve the problem of simple and hydropower operation of “Dez” reservoir in Iran and the results are presented and compared with the conventional unconstrained ACO algorithm. The results indicate the ability of the proposed methods to optimally solve large scale reservoir operation problems where the conventional heuristic methods fail to even find a feasible solution.     

A Decision Tool for Allocating the Waters of the Jordan River Basin between all Riparian Parties

Shared water resources are strong sources of conflict in the Jordan River basin shared by Israel, Jordan, Palestine, Syria and Lebanon. The control and allocation of water has been explicitly made a part of the ongoing peace negotiations. This article calls for the application of international water law in the resolution of water disputes in the negotiating process. The challenging task for negotiators is to translate water law principles into operating rules and procedures for the equitable apportionment of waters from shared water resources. The negotiators need a decision tool based upon objective criteria or standards to reach equitable entitlements to shared water resources by all parties. This paper introduces a multi-criteria decision tool as a possible approach to the problem of allocating the waters of the Jordan River between all riparian parties. The prime principle of the criteria is equitable allocation factors identified by water law. A general mathematical model was derived in which the proportional entitlements of the Jordan River basin waters were determined to the five riparians. It is hoped that, waternegotiators review this approach.     

Modelling an overdeveloped irrigation system in south India

An optimization model for irrigation planning is developed based on the experience gained from an overdeveloped irrigation system in South India. This model helps the decision maker in choosing the appropriate policy decisions under conditions of shortage of the available water potential to meet the demand of already overgrown irrigation systems. The objective of the model is to maximize the net benefits from crops in the commands of the irrigation projects considered. The constraints of the model include total land limitations of each project, subregional land limitations; reservoir balance, storage capacity, beginning‐year storage constraints for each reservoir; range of possible downstream riparian release policies; sociological constraints regarding essential food crop policy and commercial crop limitations.     

Sensitivity analysis of non-point sources in a water quality model applied to a dammed low-flow-reach river.

Downstream of Capim Branco I hydroelectric dam (Minas Gerais state, Brazil), there is the need of keeping a minimum flow of 7 m3/s. This low flow reach (LFR) has a length of 9 km. In order to raise the water level in the low flow reach, the construction of intermediate dikes along the river bed was decided. The LFR has a tributary that receives the discharge of treated wastewater. As part of this study, water quality of the low-flow reach was modelled, in order to gain insight into its possible behaviour under different scenarios (without and with intermediate dikes). QUAL2E equations were implemented in FORTRAN code. The model takes into account point-source pollution and diffuse pollution. Uncertainty analysis was performed, presenting probabilistic results and allowing identification of the more important coefficients in the LFR water-quality model. The simulated results indicate, in general, very good conditions for most of the water quality parameters The variables of more influence found in the sensitivity analysis were the conversion coefficients (without and with dikes), the initial conditions in the reach (without dikes), the non-point incremental contributions (without dikes) and the hydraulic characteristics of the reach (with dikes).     

A Continental Scale Assessment of Australia’s Potential for Irrigation

Debate about irrigation development of water resources in northern Australia has been hampered by a lack of quantitative information to enable accurate assessment of the volume of water that could potentially be regulated in the ‘North’ (north of the tropic of Capricorn). Too often the debate focuses solely on streamflow volumes and quantities of runoff. In this paper we present simple calculations to estimate a representative irrigation requirement and the potential exploitable yield in each of the 12 drainage divisions of Australia in order to more fully inform this on-going debate. Environmental, social, cultural and economic considerations are not examined. The results indicate that, despite northern Australia generating approximately 64% of the continent’s runoff, only 45% of Australia’s potentially exploitable yield is located in that portion of Australia, due to unfavourable streamflow characteristics, storage constraints and large evaporation losses. If exploitable yield and irrigation requirement were the sole factors constraining sustainable irrigation, under a full development scenario, southern Australia could hypothetically support an area of irrigation about 60% greater than that of northern Australia (based on only 36% of the country’s runoff). Using ‘best estimates’ of rainfall and evapotranspiration projected under changes in climate resulting from a moderate emissions scenario, the percentage of Australia’s exploitable yield located in northern Australia is estimated to increase from 45% to 47% by the year 2050, which equates to a 2% increase to the percentage of Australia’s hypothetical area of irrigation that could be located in northern Australia. These results suggest that efforts towards achieving and developing sustainable irrigation practices in the South will remain most important in achieving Australia’s long term irrigation potential. This study also highlights the need for better regional scale information on the potential to regulate streamflow in Australia, under current and future climates. Such information is essential to guide policy and planning, future Government and private investment, and to manage community expectations of Australia’s water resources.     

Application of Decision Support System for Sustainable Management of Water Resources in the Azraq Basin—Jordan

Abstract

Water scarcity in Jordan is a significant constraint to development, with limited available water and financial resources. As population and economic activity increase, it will be necessary to implement national strategies that seek to balance the present needs and those of future generations. Multiple variables associated with agricultural crops, industries, and the impact of climate change, were incorporated into a Decision Support System (DSS). The DSS utilized Analytical Hierarchy Process (AHP), which resulted in the prioritization of sustainable water policies for management in the Azraq Basin. The inputs to the DSS were generated through application of Modflow (groundwater), stochastic, and Penman Montieth models and through calculations of water productivity for agricultural and industrial sectors. The results of the DSS make recommendations as to how to enhance long-term sustainability of water resources in Azraq, while allowing for water utilization and economic growth. It is recommended for future planning that further research of the impacts to water resources must be conducted at local and national levels and linked to regional and global climate change prediction. It can be concluded that the DSS tool and AHP are potentially positive contributions to the process of decision- making for selection and ranking of alternatives and policies and for help in solving problems that include conflicting criteria.     

蓄滞洪区洪水演进模拟及堤防溃决损失评估方法

堤防蓄滞洪区的经济社会发展和人口数量增长与防洪矛盾日益凸显,开展蓄滞洪区洪水灾害风险评估研究具有重要的工程价值,风险评估的关键一步是估算堤防溃决损失。为了准确估算堤防溃决造成的生命、经济、生态环境损失,发展了基于MIKE21 FM模型的洪水演进模拟方法,建立了基于蓄滞洪区洪水演进淹没数据的损失评估方法。以鄱阳湖康山大堤蓄滞洪区为例,模拟获得了历史最高水位下蓄滞洪区洪水演进过程,得到了切合工程实际的淹没数据(淹没面积、水深、流速)。在此基础上,划分了灾区内受灾等级,并将洪水演进与损失计算有机结合估算得到了蓄滞洪区的生命、经济和生态环境损失。研究成果为堤防溃决风险定量评估奠定基础,为蓄滞洪区防汛抢险决策方案的制定提供有效参考依据。     

Multicriteria Analysis For Water Productivity in the Jordan Valley

Abstract

Multiple variables associated with agricultural sector, including crop water consumption, salinity tolerance, marketing, evapotranspiration and other factors related to industrial sector, were incorporated into a multi-criteria analysis (MCA). The MCA utilized Analytical Hierarchy Process (AHP) which resulted in the prioritization of water use for management in the Jordan Valley. The inputs to the MCA were generated through metrological variables for the Jordan Valley for the period 1980 to 1999. Soil data and crop data were evaluated using the EVAPOT program, the KCISA program, and the ISAREG model to estimate reference evapotranspiration, crop coefficiency, crop water requirement, and calculations of water productivity for agricultural and industrial sectors. The results of the MCA make recommendations for enhancing long-term sustainability of water resources in the Jordan Valley, while allowing for water utilization and economic growth. The MCA ranked the date palm as the highest priority crop with respect to the goal of sustainable agricultural use of water. Apparel manufacturing was the most sustainable industry. Overall, the industrial sector seems to perform better with regards to water productivity than the agricultural sector. It can be concluded that the MCA tool and ISAREG model are potentially positive contributions to the process of decision- making for selection and ranking of alternatives for help in solving problems that include conflicting criteria.     

Water Planning in Jordan

Abstract

This paper present a shift in water planning in Jordan from supply-side water management to more integrated and demand-driven water management. Assessment of existing water supply and demand is presented and strategies are outlined. Potential available water resources and uses are presented. Strategies to meet unsatisfied water demand are presented. These include use of nonconventional water resources, privatization, efficiency enhancement in distribution systems, and demand management. Scenarios for sustainable water management are developed. Each scenario was based on combinations of the role of government in the water sector and the national financial situation. Comparisons among these scenarios were performed for the case of Jordan and a set of recommendations are stated.     

小浪底水库支流倒灌与淤积形态模型试验

利用小浪底水库实体模型开展水库拦沙后期运用方式长系列年试验,对争议较大的库区支流倒灌及其淤积形态问题进行重点分析。结果表明:库区最大支流畛水河口门狭窄且库容较大,拦门沙问题最为突出,其纵坡面形态与设计有一定的差别;支流年淤积量与当年大于2600 m3/s流量时段的总水量有较好的相关性;通过优化水库运用方式可较长时期保持动态三角洲淤积形态,有利于支流库容的有效利用;水库干流河床处于动平衡状态时,支流河床仍然会逐渐淤积抬升而使得干支流淤积面高差趋于减少。     

城陵矶防洪控制水位的探讨

长期以来城陵矶控制水位既是堤防设计水位又是蓄洪工程调度运用水位,这一直是长江中游防洪问题争论的焦点。从分析现有江湖关系条件下的长江洪水特征出发,以长江中游防洪体系既定的布局为基础,结合三峡水库的调节作用,根据模型模拟结果和实际水情,提出将堤防设计水位与蓄洪工程调度水位分开,近期莲花塘防洪设计水位采用历史最高水位35.80 m、蓄洪工程调度水位采用34.4~35.80 m为宜。     

Sewer storage tank performance under climate change.

This paper describes a study of the potential effects of climate change on the design and performance of sewer storage tanks. A long-term synthetic rainfall time-series has been derived based on the IPPC medium-high emission scenario for a case study in London. Results indicate a 35% increase in the number of storm events that cause filling of the tank and a 57% increase in the average volume of storage required. A method to estimate the required future storage volume for any given return period has been developed and described. Indications are that significantly larger storage volumes will be required to maintain the same level of flood protection.     

Real-Time Operation of Reservoir System by Genetic Programming

Reservoir operation policy depends on specific values of deterministic variables and predictable actions as well as stochastic variables, in which small differences affect water release and reservoir operation efficiency. Operational rule curves of reservoir are policies which relate water release to the deterministic and stochastic variables such as storage volume and inflow. To operate a reservoir system in real time, a prediction model may be coupled with rule curves to estimate inflow as a stochastic variable. Inappropriate selection of this prediction model increases calculations and impacts the reservoir operation efficiency. Thus, extraction of an operational policy simultaneously with inflow prediction helps the operator to make an appropriate decision to calculate how much water to release from the reservoir without employing a prediction model. This paper addresses the use of genetic programming (GP) to develop a reservoir operation policy simultaneously with inflow prediction. To determine a water release policy, two operational rule curves are considered in each period by using (1) inflow and storage volume at the beginning of each period and (2) inflow of the 1^st, 2^nd, 12^th previous periods and storage volume at the beginning of each period. The obtained objective functions of those rules have only 4.86 and 0.44?% difference in the training and testing data sets. These results indicate that the proposed rule based on deterministic variables is effective in determining optimal rule curves simultaneously with inflow prediction for reservoirs.     

大洪水条件下黄河下游河道冲淤及滩区安全

在大洪水期行洪滞洪沉沙是黄河下游宽滩区的主要功能之一。近十几年来,随着黄河水沙的变化和小浪底水库的建成运用,对宽滩区运用方式的争论更为激烈,却一直缺乏系统的对比研究。为此,黄科院利用小浪底至陶城铺河道实体模型,采用2013年汛前地形,开展了黄河下游宽滩区是否修建防护堤两种不同运用方式下,大洪水期的洪水演进试验,通过对比分析不同运用方式下的下游河道在冲淤演变、洪水位变化和滩区防洪安全等方面的问题,探讨了大洪水条件下黄河下游河道冲淤及滩区的安全形势,以期为黄河下游河道治理措施的决策提供科学的参考依据。结果表明,宽滩区修建防护堤后,中常高含沙洪水条件下主槽淤积量小于不修防护堤方案,大洪水条件下主槽冲刷量大于不修防护堤方案,说明主槽过流能力和输沙能力均有所增大。但是,修建防护堤后的嫩滩淤积量,两种洪水条件下均呈现出明显大于不修防护堤方案,河道的横断面形态和"二级悬河"形势均有所恶化。同时,由于目前地形条件下夹河滩以上河段主河槽过流能力达到了6 000m3/s,洪水向下游的演进速度和水量明显增加,导致高村以下的洪水位比不修防护堤时显著提升,增大了高村以下河段的防洪压力,滩区的防洪安全受到严重威胁。     

长江上游水库群联合蓄水调度初步研究与思考

蓄水期是长江中下游地区用水需求最集中的时期,蓄水调度是实现水库综合利用任务最重要的环节。根据水库汛期承担的防洪任务,将长江上游蓄水水库分为仅承担所在支流防洪、自身无防洪任务但承担长江中下游防洪以及承担所在支流和长江中下游双重防洪任务的3种类型。重点分析了承担本河流和配合三峡水库承担长江中下游双重防洪任务的部分控制性水库防洪与蓄水的关系,并探讨了水库提前蓄水的可行性;结合来水的不确定性,分析了在特枯水年、偏枯水年和偏丰水年等不同典型年下三峡水库蓄水调度方式及应对措施。另外就水库群联合蓄水调度研究面临的挑战,提出了亟待开展的工作建议。     

Optimization of Nebhana Reservoir Water Allocation by Stochastic Dynamic Programming

This study is devoted to the identification of an optimal rule that would permit to improve the water resources management of dam in arid condition. The Nebhana dam is considered in this study as a representative of a set dams situated in such condition. The water storage is used for irrigation purpose. The identification of an optimal rule is based on two opposite objectives: the satisfaction of the irrigation water demand and the safeguard of a minimal water storage in the dam. By considering different weights for these objectives, the stochastic dynamic programming technique was lead to various optimal rules for the water resources management of the Nebhana dam. This technique takes into account the variability of the volume of water inflow to the dam on the basis of their occurrence probability; the water losses by means of forecasting models and the water resources goals using weight coefficients. The identified optimal rule would permit to estimate the necessary water release volume for irrigation by considering the water storage and the decision period.     

水位变化对赤田港堤防稳定性分析探讨

水位变化是影响堤防稳定安全的重要影响因素,为了定量分析赤田港堤防在不同水位变化条件下的迎水侧堤坡稳定安全,考虑水位变化速率影响,对堤防迎水侧进行堤坡稳定有限元计算。分析赤田港堤防在不同水位变化速率、堤坡比和冲刷深度影响下堤坡稳定安全的变化规律,对赤田港现状堤防结构优化和除险加固措施选取具有指导意义。     

利用活动坝抬高葛洲坝近坝段枯水位的方案研究

三峡水库建成后 ,葛洲坝近坝段冲刷降低枯水水位对航运的影响是重要的问题 ,各单位曾提出了许多方案。笔者用数学模型计算的方法研究了利用活动坝提高枯水位的途径 ,研究和分析了在河道中加入活动坝后上游水位抬升的效果。提出利用活动坝抬高葛洲坝近坝段枯水水位方案的初步可行性。在对活动坝影响河道的因素简化后 ,利用一维河流数学模型计算了在葛洲坝下游胭脂坝河段不同位置设置活动坝后的水面线、流速等水流参数 ,重点比较了坝布置位置以及水流流量对水位抬升的影响 ,并以此为依据提出了葛洲坝下游抬高水位的方案