An Alternative Rotational Delivery Schedule for Improved Performance of Reservoir-based Canal Irrigation System

Alternative delivery scheduling approaches were tried to overcome the problem of low efficiency in eastern Indian irrigation projects. The features of the existing delivery schedules in the Left Bank Feeder Canal (LBFC) system of Kangsabati irrigation project, located in the state of West Bengal, India, have been studied. Four simulation scenarios were considered in the study. These are (1) actual canal scheduling with original transplanting date (S1), (2) Integrated Reservoir-based Canal Irrigation Model (IRCIM) scheduling for usual transplanting date (S2), (3) IRCIM scheduling for 5 days advanced transplanting date (S3), and (4) IRCIM scheduling for 5 days lagged transplanting date (S4). An attempt was made to develop a year-independent alternative delivery schedule based on the analysis of 11 years simulation results with all the above scenarios. For maximum number of simulation years, model performance was better for paddy transplanted on July 24, three irrigations from the reservoir between transplanting and harvesting, and restricting the release to minimum rule curve (MRC), i.e., maintaining the stage on any day above the minimum stage actually found in 16 years period. Hence, it was proposed as the year-independent alternative delivery schedule. This alternative delivery schedule saved 18.36% irrigation water over actual schedules, but increased the crop evapotranspiration by 0.61%. The proposed alternative delivery schedule also considered both the expected dry spells as well as critical growth periods of the crop during the simulation period. Thus, it was recommended to adopt the alternative delivery schedule instead of existing delivery schedule in the future years for the LBFC system of Kangsabati irrigation project.     

Optimization and risk analyses for rule curves of reservoir operation: application to Tien-Hua-Hu Reservoir in Taiwan.

Tien-Hua-Hu Reservoir is currently under planning by the Water Resources Agency, Taiwan to meet the increasing water demands of central Taiwan arising from rapid growth of domestic water supply, and high-tech industrial parks. This study develops a simulation model for the ten-day period reservoir operation to calculate the ten-day water shortage index under varying rule curves. A genetic algorithm is coupled to the simulation model to find the optimal rule curves using the minimum ten-day water shortage index as an objective function. This study generates many sets of synthetic streamflows for risk, reliability, resiliency, and vulnerability analyses of reservoir operation. ARMA and disaggregation models are developed and applied to the synthetic streamflow generation. The optimal rule curves obtained from this study perform better in the ten-day shortage index when compared to the originally designed rule curves from a previous study. The optimal rule curves are also superior to the originally designed rule curves in terms of vulnerability. However, in terms of reliability and resiliency, the optimal rule curves are inferior to the those originally designed. Results from this study have provided in general a set of improved rule curves for operation of the Tien-Hua-Hu Reservoir. Furthermore, results from reliability, resiliency and vulnerability analyses offer much useful information for decision making in reservoir operation.     

Optimizing Reservoir Operation Policy Using Chance Constraint Nonlinear Programming for Koga Irrigation Dam,Ethiopia

One of typical problems in water resources system modeling is derivation of optimal operating policy for reservoir to ensure water is used more efficiently. This paper introduces optimization analysis to determine monthly reservoir operating policies for five scenarios of predetermined cropping patterns for Koga irrigation scheme, Ethiopia. The objective function of the model was set to minimize the sum of squared deviation (SSD) from the desired targeted supply. Reservoir operation under different water availability and thresholds of irrigation demands has been analyzed by running a chance constraint nonlinear programming model based on uncertain inflow data. The model was optimized using Microsoft Excel Solver. The lowest SSD and vulnerability, and the highest volumetric reliability were gained at irrigation deficit thresholds of 20 % under scenario I, 30 % under scenario II, III and V, and at 40 % under scenario IV when compensation release is permitted for downstream environment. These thresholds of deficits could be reduced by 10 % for all scenarios if compensation release is not permitted. In conclusion the reservoir water is not sufficient enough to meet 100 % irrigation demand for design command areas of 7,000 ha. The developed model could be used for real time reservoir operation decision making for similar reservoir irrigation systems. In this specific case study system, attempt should be made to evaluate the technical performance of the scheme and introduce a regulated deficit irrigation application.     

面向双保证率的水库供水能力优化计算方法研究

随着城市化进程的推进和生态文明理念的深入,水库供水任务日趋复杂,涵盖城镇供水、农业灌溉、生态保障多类目标,分析水库多目标供水能力对于工程的功能调整等决策十分必要。本文综合考虑水库供水目标的竞争性与保证率差异性,提出面向双保证率的水库供水能力双层优化计算方法,通过调度线控制和城镇供水能力区间迭代实现满足不同保证率的多目标供水能力计算。外层基于粒子群算法以城镇供水能力最大为目标对水库调度线进行优化,协调不同用户的供水关系;内层在给定规则下通过迭代计算满足双保证率要求的城镇供水能力。通过内外层嵌套计算实现对水库调度规则和供水能力的同步优化。以三亚市赤田水库为实例进行研究,在城镇供水保证率为95%、农业灌溉保证率为90%时,通过优化调度规则得出水库总供水能力为9400万m~3。设置不同农业保证率和农业需水情景作分析对比,二者均对城镇供水能力有影响,总供水能力随农业保证率降低而提高。分析表明,双层优化计算方法可以实现对调度线的优化,得出满足城镇、农业双保证率要求的供水能力,且计算方法收敛稳定性较高,优化生成的调度线年内分布合理,可为水库多目标供水能力的计算和相关决策提供参考。     

Reservoir Optimization-Simulation with a Sediment Evacuation Model to Minimize Irrigation Deficits

Importance of existing reservoirs for supplying fresh water has increased significantly due to population increase and enhanced living standards, while the reduced development of new reservoirs in recent decades has made it even more pertinent that the current battery of reservoirs be operated in a sustainable and efficient manner. In order to move a step towards the goal of sustainability, sediment evacuation must be considered when optimizing a reservoir??s operations. The Reservoir Optimization-Simulation with Sediment Evacuation (ROSSE) model is a recently developed tool which internalizes sediment evacuation routines and the simulation module in a newly developed GA-based optimization module. This article applies the ROSSE model with the aim of minimizing irrigation shortages in the Tarbela Reservoir, Pakistan. The article also calculates the suitable values of various GA parameters required to run the model through a sensitivity analysis. Simulation results of three sets of rule curves??one existing and two optimized sets??are compared with each other for parameters like irrigation shortage, power generation, sediment evacuation and flood dis-benefits (damages). It is found that the optimized rule curves of scenario 1 reduce the irrigation shortages by 39?% while the optimized rule curves of scenario 2 can reduce the irrigation shortages by 24?% of that of the shortages by existing rule curves. The optimized rule curves of scenario 2 also ensure the current level of hydropower generation and sediment evacuation for the Tarbela reservoir. The study recommends a change in the reservoir??s existing rule curves in order to reduce irrigation shortages. The incorporation of the sediment evacuation routine and availability of economic and hydro based objective functions in the optimization model will help achieving the goal of sustainability.     

Single Reservoir Operating Policies Using Genetic Algorithm

To obtain optimal operating rules for storage reservoirs, large numbers of simulation and optimization models have been developed over the past several decades, which vary significantly in their mechanisms and applications. As every model has its own limitations, the selection of appropriate model for derivation of reservoir operating rule curves is difficult and most often there is a scope for further improvement as the model selection depends on data available. Hence, evaluation and modifications related to the reservoir operation remain classical. In the present study a Genetic Algorithm model has been developed and applied to Pechiparai reservoir in Tamil Nadu, India to derive the optimal operational strategies. The objective function is set to minimize the annual sum of squared deviation form desired irrigation release and desired storage volume. The decision variables are release for irrigation and other demands (industrial and municipal demands), from the reservoir. Since the rule curves are derived through random search it is found that the releases are same as that of demand requirements. Hence based on the present case study it is concluded that GA model could perform better if applied in real world operation of the reservoir.     

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.     

Reliability analysis for reservoir water supply due to uncertainties in hydrological factors,rainfall-runoff routing and operating rule curves

This study aims at developing a reliability-analysis model (RA_WS_RES) to quantify the effect of variations in uncertainties factors regarding the reservoir inflow and outflow at various 10-day periods on the reliability of water supply from the reservoir. The uncertainty factors considered are classified into three types: the hydrological factors (rainfall, baseflow, and initial water level of the reservoir), the reservoir operation rules for the water-allocation model (RIBASIM), and the parameters of rainfall-runoff model (i.e. Sacramento Soil Moisture Accounting, SAC-SMA). In the proposed RA_WS_RES model, the reliability of the water supply attributed to the uncertainty factors considered can be quantified by collaborating the multivariate Monte Carlo simulation (MMCS) methods and uncertainty-risk (advanced first order and second moment, AFOSM) analysis. Shihmen Reservoir watershed in Northern Taiwan is selected as the study area and four associated demand nodes are regarded as the study nodes; the hourly rainfall data from 1987 to 2014 and other hydrological data (i.e. rainfall, baseflow, and initial water level of the reservoir) as well as the operation rule curves are adopted in the model development and application. The results from the numerical experiences indicate that among the uncertainty factors concerned, the average rainfall depth at the current 10-day period and the range between the lower and critical levels are more sensitive to the estimation of water supply from Shihmen Reservoir. Additionally, the impact of variation in baseflow on the reliability of the water supply from Shihmen Reservoir should be taken into account, especially in the dry season. In addition to rainfall and baseflow, the initial water level should be an important source for the water supply, and its effect gradually reduces with the 10-day period. Furthermore, the reliability of water supply is obviously impacted by the uncertainty in the range between the lower and critical rule level, especially in the dry season, due to its range being adversely related with the water supply. Eventually, the proposed RA_WS_RES model can effectively and reasonably quantify the reliability of water supply attributed to variations in uncertainty factors at different 10-day period under the consideration of climate change.     

云南蜻蛉河大型灌区水库联合优化调度

针对蜻蛉河大型灌区在干旱条件下的水资源供需矛盾突出的问题,选取径流资料、灌区用水资料和水库资料建立了灌区水库优化调度模型。结果表明:在保证率为75%的情况下引水总量为668.25万m3;其中胡家山水库引水最多,大康郎水库引水最少。     

关于衣干其水库淤积问题的浅谈

衣干其水库是叶尔羌河中游灌区的一座平原灌注式水库,该水库引叶尔羌河河水,叶尔羌河是一条多泥沙河流,就衣干其水库运行40多年来发生的淤积过程及规律进行分析。     

Water Management of Irrigation Dams Considering Climate Variation: Case Study of Zayandeh-rud Reservoir, Iran

Dependency of reservoir operation on the climate variation occurs especially in regions, where agricultural demand has a significant share of the total water demands. The variability between demands that are based on annual climate conditions may be larger than the uncertainty associated with other explanatory variables in long-term operation of an irrigation dam. This paper proposed a rule curves to the water managers of the Zayandeh-rud reservoir in Iran in long-lead reservoir operation. A regional optimal allocation of water among different crops and irrigation units is developed. The optimal allocation model is coupled with a reservoir operating model, which is developed based on the certain hedging that deals with the available water and the water demands mutually. This coupled model is able to activate restrictions on allocating water to agricultural demands considering variation of inflow to the reservoir, variation of demands and the economic value of allocating water among different crops and irrigation units. The resulted rule curve is presented with a number of tables for more details and accuracy and a simple curve, which is more useful for operational purpose.     

Impact of climate on the vertical water column structure of Lajes Reservoir (Brazil): A tropical reservoir case

Ribeirão das Lajes Reservoir was constructed in 1905 for energy production, and is now used as a domestic water supply for about 1 million people. The reservoir was considered as being general monomictic, exhibiting water column mixing in the winter. Water column mixing, however, did not occur in the deepest parts of the reservoir in the warm year of 2005. Nevertheless, the long stratification period leads to an anoxic, nutrient-rich hypolimnion that exhibits poor water quality in the deepest part. The meteorological events of cold front passages in the reservoir region were not able to disrupt the water column stability, or affect its water quality for domestic supply. Maintenance of thermal stratification over most of the year was likely because of the low influence of wind, long water retention time, and the input of cold water from the tributary and from rain directly draining into the metalimnion.     

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.     

Application of Integrated Hydrologic and River Basin Management Modeling for the Optimal Development of a Multi-Purpose Reservoir Project

Multi-purpose reservoir development have been always a big challenge for the management of water resources. This paper describes an integrated approach for investigating catchment hydrology in the development of a hydropower and a canal irrigation system based on model analyses. The investigation aims to adequately determine an optimal domestic and irrigation water resources allocation scheme based on an assessment of the reservoir water balance and capacity for hydropower. The soil and water assessment tool (SWAT) which characterizes basin hydrology and the water management and planning model MODSIM which provides a decision support system for water allocation optimization, were used in this study. The integrated approach was applied to Prek Te River basin in Cambodia. The water demand aspect was examined based on domestic water use, irrigation water, environmental flow, and water losses. An operational rule curve was developed for hydropower operation with respect to a power potential of 13 MW. Hydrologic modeling revealed 90 % dependable water of about 2.7 m³/s during the dry season and 214.3 m³/s during the wet season, indicative of a wet-season dependent reservoir for storage. Results from the 26-years simulation period also showed that diversions for domestic water and irrigation water supply were 92.3 % dependable for a 13 MW capacity hydropower development. The integrated approach was shown to be a valuable decision support tool for water resources management with the determination of an optimum policy for multi-purpose reservoir operation based on available basin water supply.     

Evaluation of Real-Time Operation Rules in Reservoir Systems Operation

Reservoir operation rules are logical or mathematical equations that take into account system variables to calculate water release from a reservoir based on inflow and storage volume values. In fact, previous experiences of the system are used to balance reservoir system parameters in each operational period. Commonly, reservoir operation rules have been considered to be linear decision rules (LDRs) and constant coefficients developed by using various optimization procedures. This paper addresses the application of real-time operation rules on a reservoir system whose purpose is to supply total downstream demand. Those rules include standard operation policy (SOP), stochastic dynamic programming (SDP), LDR, and nonlinear decision rule (NLDR) with various orders of inflow and reservoir storage volume. Also, a multi-attribute decision method, elimination and choice expressing reality (ELECTRE)-I, with a combination of indices, objective functions, and reservoir performance criteria (reliability, resiliency, and vulnerability) are used to rank the aforementioned rules. The ranking method employs two combinations of indices: (1) performance criteria and (2) objective function and performance criteria by using the same weights for all criteria. Results show that the NLDR gives an appropriate rule for real-time operation. Moreover, NLDR validation is presented by testing predefined curves for dry, normal, and wet years.     

Optimization of Multi-Reservoir Operating Rules for a Water Supply System

To obtain the optimal releases of the multi-reservoir system, two sets of joint operating rules (JOR-I and JOR-II) are presented based on the aggregation-disaggregation approach and multi-reservoir approach respectively. In JOR-I, all reservoirs are aggregated to an equivalent reservoir, the operating rules of which, the release rule of the system is optimized following operating rule curves coupled with hedging rules. Then the system release is disaggregated into each reservoir according to water supply priorities and the dynamic demand partition approach. In JOR-II, a two-stage demand partition approach is applied to allocate the different demand priorities to determine the release from each reservoir. To assess the reliability and effectiveness of the joint operating rules, the proposed rules are applied to a multi-reservoir system in Liaoning province of China. Results demonstrate that JOR-I is suitable for high-dimensional multi-reservoir operation problems with large-scale inflow data, while JOR-II is suitable for low-dimensional multi-reservoir operation problems with small-scale inflow data, and JOR-II performs better than JOR-I but requires more computation time. The research provides guidelines for the management of multi-reservoir system.     

黄河三门峡以下流域水资源调配研究

黄河三门峡以下河段水资源供需紧张、断流频繁。本文针对此问题，采用月径流量延时曲线和超越机率曲线、系统仿真方法研究黄河三门峡以下流域在不同来流条件下水资源的供需情势，研究结果表明：(1)小浪底水库的兴建，大大改善了三门峡以下水资源的供需状况，但在来水较枯的年份，水资源供给仍然紧张；(2)在枯水年份，三门峡以下即使再增加水库或加大库容，也不能缓解水资源的供需紧张状况，要解决缺水状况主要依靠上游水库调节水量或采取节约用水的措施。     

十堰市中心城区水资源配置方案研究

为解决十堰市中心城区水资源供需矛盾,实现地区水资源的合理配置,在地区现状供用水情况调查评价、需水预测的基础上,利用VBA语言编程,建立了十堰市中心城区水资源配置模型,对地区现状基准年和规划水平年水资源供需平衡情况进行计算分析,并拟定了堵河潘口水库引水工程与本地水库工程联合调度供水的水资源配置方案。本文对十堰市中心城区水资源配置方案、配置模型的建立过程以及模型计算结果进行了介绍,并重点分析了水资源配置方案中以马家河水库、茅塔河水库作为充蓄调节水库,在减少潘口引水工程设计规模、提供潘口引水工程检修期供水两方面的作用。     

桦甸市城区新水源规划报告

本文根据桦甸市城市水资源状况与目前存在的水资源供需矛盾，提出将关门砬子水库由以灌溉为主扩建为以城市供水为主的综合利用水库，并结合大量资料进行了分析比较，认为，此规划方案经济可行，目前该水库一期扩建工程已完工，桦 甸市的水资源供需矛盾基本得到解决。     

Reservoir Operation Modelling with Fuzzy Logic

In this article, a fuzzy rule based model is developed for the operation of a single purpose reservoir. The model operates on an 'if – then' principle, where the 'if' is a vector of fuzzy premises and the 'then' is a vector of fuzzy consequences. The steps involved in the development of the model include, construction of membership functions for the inflow, storage, demand and the release, formulation of fuzzyrules, implication and defuzzification. The methodology is illustrated through the case study of the Malaprabha irrigation reservoir in Karnataka, India. Reservoir storage, inflow, and demands are used as premises and the release as the consequence.Simulated reservoir operation with a steady state policy provides the knowledge base necessary for the formulation of the Fuzzy rules.