Planning Of Water Supply Systems Research Articles

Assessment of ERA5-Land Data in Medium-Term Drinking Water Demand Modelling with Deep Learning

Drinking water demand modelling and forecasting is a crucial task for sustainable management and planning of water supply systems. Despite many short-term investigations, the medium-term problem needs better exploration, particularly the analysis and assessment of meteorological data for forecasting drinking water demand. This work proposes to analyse the suitability of ERA5-Land reanalysis data as weather input in water demand modelling. A multivariate deep learning model based on the long short-term memory architecture is used in this study over a prediction horizon ranging from seven days to two months. The performance of the model, fed by ground station data and ERA5-Land data, is compared and analysed. Close-to-operative forecasting is then presented using observed data for training and ERA5-Land dataset for testing. The results highlight the reliability of the proposed architecture fed by ERA5-Land data for different time horizons. In particular, the ERA5-Land shows promising performance as input of the multivariate machine learning forecasting model, although some meteorological biases are present, which can be improved, especially in close-to-operative application with bias correction techniques. The proposed study leads to practical implications in the use of regional climate model outputs to support drinking water forecasting for sustainable and efficient management of water distribution systems.

Resilience-based water main rehabilitation planning in a multi-hazard context

Due to aging beyond the intended design life, many water mains in the USA are currently deteriorated resulting in an increasing number of failures which challenge water utilities with diminished supply reliabilities, loss of treated water, and numerous other societal issues. Water pipeline systems serving regions that are naturally vulnerable to external hazards, such as earthquakes, pose additional challenges. Numerous vulnerabilities such as these must be congruently analyzed for optimal capital improvement planning of water supply systems. A resilience-based rehabilitation planning framework is presented and demonstrated in this paper to coherently integrate the vulnerabilities of water pipelines to seismic hazards and natural deterioration. The artificial bee colony (ABC), shuffled frog leaping (SFLA), and genetic algorithms (GA) are investigated to identify the best performing optimization algorithm to be used in the modeling framework presented in this study. A scenario of a real-world water supply system operating in the earthquake-prone region in South Carolina is used for demonstrating the rehabilitation framework. The study approach and the presented findings will provide guidance to water utility professionals in optimal capital improvement planning to enhance supply resilience to a multitude of vulnerabilities.

Remote-Sensing Applications to Support Rehabilitation of Water Infrastructure in Lapilang, Nepal

Disasters such as the earthquakes that struck Nepal in spring 2015 not only cause direct impacts of death and injuries to people, but also have long-term effects such as the destruction of vital infrastructure. To support the restoration of such infrastructure, remote-sensing applications can be helpful due to their potential to be complementary to in-situ data. In this study, GIS analyses are applied to Earth observation (EO) data in order to support the rehabilitation of water supply infrastructure planned by the Earthquake Recovery Operation of the Nepal Red Cross Society in the area of Lapilang, Nepal. Various aspects that are important for effective and sustainable planning are examined: (1) provision of accurate elevation information with a spatial resolution of 2m to support the planning of water supply systems; (2) mapping the distribution of buildings as a proxy for population distribution in order to facilitate a spatially explicit estimate of water demand; (3) identifying potential locations for community water taps that fulfil national standards; (4) the assessment of landcover / land use in watershed areas to estimate meliorating effects and potential contamination risks. The mapped results of the analysis are not only essential for onsite field work, but can also facilitate informed decision-making processes for both short- and long-term planning of water supply systems in the area.

Empirical Analysis of Water-Main Failure Consequences

Modern urban societies depend greatly on critical lifeline systems such as drinking water supply. Water supply systems in the United States comprise about one million mile length of interconnected pipelines that transport water from sources to consumption points with the support of treatment plants, pumping stations, storage tanks and valves. While depleting freshwater sources in some regions is an alarming concern, supply infrastructure woes exacerbate the problem of meeting supply reliability targets. Evidenced by the “D” or lower grade it has been receiving over the past few ASCE infrastructure report cards, the quality of water supply infrastructure has degraded to an extent where 240,000 water mains fail annually in the U.S. A majority of these failures result in significant economic, environmental and societal consequences. Pro-active rehabilitation of deteriorated infrastructure will avoid these unwarranted failure consequences. This paper employs empirical analysis of the economic, environmental and societal consequences of large-diameter water main failures to estimate their overall impact cost. Data on the impacts of 11 large-diameter water main failures has been gathered and synthesized. The results of this paper will aid in predicting the future water main failure consequences to enable risk-based, long-term capital improvement planning of water supply systems.

Optimal planning of water supply system for long-term sustainability

Developing a long-term system plan for sustainable water supply is a challenging task due to system complexity and future uncertainties in water demands and source availability. Here a coupled optimization model is proposed for water supply system design and long-term operations by deciding system component sizes and water flow allocations simultaneously. The objective is to minimize overall system costs (i.e., sum of capital and operation costs) while meeting water demands and operational constraints. The economic costs include initial component construction costs and operation expenditure over pre-defined operation years. The proposed model integrates a genetic algorithm with a linear programming model to optimize water infrastructure investments and annual water transfers satisfying flow constraints. The coupled model was applied to a simplified water supply network composed of multiple water sources and users. For the application network, various qualities of water from different sources could be supplied to different users. Plausible future scenarios with time varying water demands were simulated representing potential future conditions. Application results show that the proposed coupled model is beneficial in decision making process to design structural components in near future and prepare long-term policies for water shortage and water right issues in upcoming years. The model can be tailored to a specific system and various regulations and conditions can be incorporated within the model without adding complexity to the optimization framework.

Performance Analysis and Optimal Operational Planning of Water Supply Systems

From the viewpoints of energy and cost savings, it is important to rationally operate water supply systems composed of pumps, piping, and reservoirs. However, it is very difficult, because nonlinear performance characteristics of pumps and piping, discrete performance characteristics due to the combination for on/off status of pumps, and daily operational strategies of reservoirs must be considered. In this paper, a two-stage approach to the performance analysis and optimal operational planning of a water supply system is proposed. At the first stage, the performance characteristics of pumps and piping are analyzed by the Newton-Raphson method, and are optimized with respect to the combination for on/off status and revolution speed ratios of pumps by the enumeration and nonlinear programming methods, respectively. At the second stage, the daily operational strategy of the system is optimized with respect to the storage level of a reservoir by the dynamic programming method. A case study is conducted to show the effectiveness of this approach.

Robustness of water resources systems

When water resource systems investments are made there is little assurance that the predicted performance will coincide with the actual performance. Robustness is proposed as a measure of the likelihood that the actual cost of a proposed project will not exceed some fraction of the minimum possible cost of a system designed for the actual conditions that occur in the future. The robustness criterion is illustrated by its application to the planning of water supply systems in southwestern Sweden.

ON THE ESTIMATE OF PER CAPITA WATER USE IN A MUNICIPALITY

Per capita waer use is one of the most important variables in the evaluation of amounts of water consumption and in the planning of water supply systems. The estimating procedures, that have hitherto been adopted in the past Japanese studies dealing with municiplities, are far from being justifiable. This paper discusses problems on the estimate of per capita water use, based on a case study of IchiharaShi, Chiba Prefecture. In conclusion, the follwings are emphasized for the detailed estimate of per capita water use: municipal water demands depend on the two sorts of water users, that is, residential users and users who consume a large quantity of water such as public baths, hotels, big stores and industries. These two should clearly be differentiated from each other in studies on municipal water demands. It is of importance that per capita water use is estimated on the basis of amounts of water used for just residential purposes.