Managing Apparent Loss and Real Loss from the Nexus Perspective Using System Dynamics

When water utilities establish water loss control programs, they traditionally focus on apparent loss rather than real loss when considering economic feasibility in the water sector. There is an urgent need for new management approaches that can address complex relationships and ensure the sustainability of natural resources among different sectors. This study suggests a novel approach for water utilities to manage water losses from the water-energy (WE) Nexus perspective. The Nexus model uses system dynamics to simulate twelve scenarios with the differing status of water loss and energy intensities. This analysis identifies real loss as one of the main causes of resource waste and an essential factor from the Nexus perspective. It also demonstrates that the energy intensity of each process in the urban water system has a significant impact on resource use and transfer. The consumption and movement of resources can be quantified in each process involved in the urban water system to distinguish central and vulnerable processes. This study suggests that the Nexus approach can strongly contribute to quantifying the use and movement of resources between water and energy sectors and the strategic formulation of sustainable and systematic water loss management strategies from the Nexus perspective.

Modeling wind drift and evaporation losses during sprinkler irrigation in arid areas (case of Touggourt - Algeria)

In recent years, agriculture development in South-eastern Algeria progressed rapidly which increased the demand for agricultural products. Given that this region is characterized by hard agro-climatic conditions, irrigation seems to be a necessary factor for ensuring optimal development and high agricultural production. Like many irrigation technics widely used, sprinkler irrigation performance was considerably affected by these conditions, mainly evaporation, which causes water losses. This study aims to propose an adequate mathematical model predicting wind drift and evaporation losses under different weather conditions resume by the complex indicator of climatic intensity (ɸ). Results showed that complex indicators of climatic intensity, were significant factors affecting the wind drift and evaporation losses, puissance relationship between wind drift and evaporation losses, and complex indicators of climatic intensity, obtained model are adopted can be useful tools in the determination of the overall losses in terms of environmental conditions (air temperature, relative humidity, and wind speed). Totally 25 measure samples were used for training the model, and 15 measure samples for testing and validation of the model. The developed model for the WDEL modeling shows high good performance with a coefficient of determination (R2) = 0.808, mean squared error (RMSE) = 3.39%, and Mean Absolute Error MAE = 8.41%.

Probabilistic Minimum Night Flow Estimation in Water Distribution Networks and Comparison with the Water Balance Approach: Large-Scale Application to the City Center of Patras in Western Greece

Quantification of water losses (WL) in water distribution networks (WDNs) is a crucial task towards the development of proper strategies to reduce them. Currently, WL estimation methods rely on semi-empirical assumptions and different implementation strategies that increase the uncertainty of the obtained estimates. In this work, we compare the effectiveness and robustness of two widely applied WL estimation approaches found in the international literature: (a) the water balance, or top-down, approach introduced by the International Water Association (IWA), and (b) the bottom-up or minimum night flow (MNF) approach, based on a recently proposed probabilistic MNF estimation method. In doing so, we use users’ consumption and flow-pressure data from the 4 largest pressure management areas (PMAs) of the WDN of the city of Patras (the third largest city in Greece), which consist of more than 200 km of pipeline, cover the entire city center of Patras, and serve approximately 58,000 consumers. The obtained results show that: (a) when MNF estimation is done in a rigorous statistical setting from high resolution flow-pressure timeseries, and (b) there is sufficient understanding of the consumption types and patterns during day and night hours, the two approaches effectively converge, allowing for more reliable estimation of the individual WL components. In addition, when high resolution flow-pressure timeseries are available at the inlets of PMAs, the suggested version of the bottom-up approach with probabilistic estimation of MNF should be preferred as less sensitive, while allowing for confidence interval estimation of the individual components of water losses and development of proper strategies to reduce them.

Rehabilitation in Intermittent Water Distribution Networks for Optimal Operation

Equitable distribution of water is a growing source of worry, and concerns water systems’ managers as water-stressed areas steadily increase and situations of water scarcity are becoming more frequent. The problem goes beyond just the water sector and globally affects many countries’ economies since water resources have multiple uses (i.e., power generation, irrigation, etc.). One of the various strategies to overcome periods of extreme events (e.g., water scarcity) is the adoption of intermittent operation. Intermittent operation can minimize water losses, and manages to supply the same water demand (in terms of volume) during a reduced period of time. However, despite minimizing water losses, the energy consumption necessary to cope with the increased flows and head loss, due to the reduced number of operating hours, increases. This paper explores a strategy based on rehabilitation of the system’s main pipes. It also considers optimal selection and scheduling of pumps aiming at improving the system’s hydraulic parameters (e.g., velocity and head losses) and at reducing the operating costs. Both selection and scheduling of pumps and resizing of main pipes are optimized using Particle Swarm Optimization. The obtained results show that this strategy can significantly reduce the energy consumed and can be economically feasible.

Review on Conservation of Water by Water Audit

Water is used almost in every sector, growth in population and increase in the standard of living of people so demand is increased. Water is used by all the living creatures found in the world but a very small portion of water is available for drinking and other purposes. This available usable water is mismanaged by human beings, for this mismanagement of water introducing a tool by IWA/AWWA is water-audit. Water-audit is used for reducing water-losses, leakages and gives the information of water used by consumers. Environment audit carried out in stages, water audit also consists of many stages. In this review paper, case studies are highlighted, which gives the general methodology adopted for auditing. Water balance sheet is very useful for understanding the types of losses and type of water used in particular DMA (District Metered Area). Due to the loss of water Non-revenue water is increased, for reducing losses requires huge investments.

Determining the best strategy to reduce losses in Banias water network, based on the Analytical Hierarchy Process AHP: تحديد الاستراتيجية الأفضل لتخفيف الفواقد في شبكة مياه مدينة بانياس بالاعتماد على طريقة التحليل الهرمي Analytical Hierarchy Process (AHP)

The study aims to choose the best strategy for reducing Water losses in Banias City Water Distribution network, that reaches a large percentage about 65%, based on the Analytical Hierarchy Process (AHP). The strategies (alternatives), the main and secondary criteria necessary to reach the construction of the decision matrix and the development of the final strategies for the work of the Establishment in accordance with it, based on the opinions of experts in the Banias Water Establishment, in addition to references and previous studies in the field of research. The necessary questionnaire was prepared and then distributed to a group of experts (30 experts) of engineers and technicians working in Banias Water Establishment, and thus conducting comparison process between the main criteria, the sub- criteria, and the alternatives for the sub- criteria. The Expert Choice Software Which is based on AHP method, is used, and It automatically performs mathematical processes and calculates final relative weights to obtain the final decision matrix. The results showed that the strategy of dividing the network into district metered areas ranked first, with the highest rating of 27.8%, followed by the strategy of control and pressure management with 13.6%, while the strategy of replacing meters came last with 3.5%.

Soil Moisture Depletion Modelling Using a TDR Multi-Sensor System, GIS, Soil Analyzes, Precision Agriculture and Remote Sensing on Maize for Improved Irrigation-Fertilization Decisions

The effects of three drip irrigation (IR1: Farmer’s, IR2:Full (100%ETc), IR3:Deficit (80%ETc) irrigation), and two fertilization (Ft1, Ft2) treatments were studied on maize yield and biomass by applying new agro-technologies (TDR—sensors for soil moisture (SM) measurements, Precision Agriculture, Remote Sensing—NDVI (Sentinel-2 satellite sensor), soil-hydraulic analyses and Geostatistical models, SM-rootzone modelling-2D-GIS mapping). A daily soil moisture depletion (SMDp) model was developed. The two-way-ANOVA statistical analysis results revealed that irrigation (IR3 = best) and fertilization treatments (Ft1 = best) significantly affect yield and biomass. Deficit irrigation and proper fertilization based on new agro-technologies for improved management decisions can result in substantial improvement on yield (+116.10%) and biomass (+119.71%) with less net water use (−7.49%) and reduced drainage water losses (−41.02%).

Examining the Effectiveness of Catch Crops as a Nature-Based Solution to Mitigate Surface Soil and Water Losses as an Environmental Regional Concern

The main goal of this research was to conduct a biophysical, economic, social, and perception-based approach to foresee the solutions that could be used to mitigate the soil loss problem cost-effectively in “La Ribera del Xúquer” district (Valencia Region, Spain). To achieve these goals, a farmer perception survey was carried out, and an assessment of the biophysical impact of catch crops on soil organic matter, bulk density, steady-state infiltration rate (double-ring infiltrometer) and runoff generation, and soil erosion (rainfall simulation experiments) was carried out in 2016. For the biophysical approach, two paired plots, i.e., catch crops vs. glyphosate herbicide treatment (in advance, control plot), were selected under clementine citrus production. The results show that soil organic matter increased from 1.14 to 1.63%, and bulk density decreased from 1.47 to 1.27 g cm−3 after 10 years of treatments using catch crops. They also facilitated higher infiltration rates from 16.7 to 171 mm h−1 and a delay in runoff generation from 149 to 654 s for control and catch crop plots. Both runoff rates (from 50.6 to 3.1%) and soil erosion (from 3.9 to 0.04 Mg ha−1 h−1) were reduced once the catch crops were deployed in the field. After surveying (2018–2019), farmers stated the use of catch crops as a speck of dirt and a cause of possible loss of reputation when used. Moreover, farmers (N = 73) would accept the catch crops as an effective nature-based alternative only if a subsidy of 131.17€ ha−1 would be paid. The survey results also demonstrated that the farmers' community would see catch crop more as a benefit for the planet's health and society. Few constraints, such as ageing of the farmers’ population, lack of education and negative perception for other management factors, are the critical detrimental factors for adopting catch crops as a nature-based solution to reduce soil and water losses. There is a need for an effective agrarian extension service to change the fate of the current agriculture and achieve sustainability by adopting new management strategies in contemporary agricultural practices.

Implications of the Resource Nexus on International Relations: The Case of the Grand Ethiopian Renaissance Dam

The Grand Ethiopian Renaissance Dam is causing tensions and potential for conflict along the Nile. Egypt fears water losses and threatens sanctions; Ethiopia plans to expand the electric power supply. The United Nations Security Council is advocating negotiations under the auspices of the African Union. Against this backdrop, this article discusses the nexus between water and energy in International Relations. A constructivist perspective helps to elaborate potential solutions on energy systems, water demand management and food that may be helpful in upcoming talks and in institution-building in similar endeavours.

Integrated approach to reducing drinking water losses in the distribution networks in the city of Sebastopol

Природный дефицит водных ресурсов в сочетании с высокой степенью износа систем водоснабжения обусловливает напряженную ситуацию с обеспечением питьевой водой в Крыму. За последние несколько лет для решения проблемы на региональном и федеральном уровне были разработаны и реализуются программы модернизации водного хозяйства полуострова. Одной из ключевых задач этих программ является снижение потерь воды, которые в настоящее время достигают 40–60%. Описан комплекс мероприятий, направленных на снижение потерь воды в г. Севастополе. Комплекс мер, разработанный в соответствии с международным опытом и российскими рекомендациями, учитывает существующее состояние системы водоснабжения Крыма. Мероприятия включают в себя создание современного комплекса управления сетями, зонирование водопроводной сети, регулирование давления, мониторинг и устранение утечек. По результатам анализа производственных показателей определено, что первоочередным мероприятием для Севастополя является внедрение современной системы акустического мониторинга на распределительных сетях, которая позволит эффективно обнаруживать скрытые утечки и сэкономить городу тысячи кубометров дефицитной питьевой воды. Описаны результаты пилотного проекта по обследованию 5 км водопроводных сетей системой акустического мониторинга. The natural scarcity of water resources coupled with a high degree of deterioration of water supply systems result in a tense situation with the drinking water supply in Crimea. Over the past few years, a number of programs of upgrading the peninsula's water industry have been developed and are being implemented in order to solve the problem at the regional and federal levels. One of the key objectives of these programs is to reduce water losses that currently reach 40–60%. A set of measures aimed at reducing water losses in Sebastopol is described. The set of measures developed in accordance with the international experience and Russian recommendations takes into account the current condition of the Crimean water supply system. The activities include designing an advanced network management complex, zoning of the water supply network, pressure regulation, monitoring and elimination of leaks. Based on the results of the analysis of the performance indicators, it was determined that the priority measure for Sebastopol was the introduction of an advanced acoustic monitoring system in the water distribution networks that would provide for detecting effectively latent leaks and saving the city thousands of cubic meters of scarce drinking water. The results of a pilot project on the inspection of 5 km of the water supply networks using the acoustic monitoring system are described.