scholarly journals Assessment of Water Resources and Analysis of Safe Yield and Reliability of Surface Water Reservoirs of Asmara Water Supply System

2017 ◽  
Vol 7 (1) ◽  
pp. 45
Author(s):  
Kahsay N. Zeraebruk ◽  
Alfred O. Mayabi ◽  
John M. Gathenya

In a water supply system safe yield is the average annual volume that can be supplied to the system subject to an adopted set of operational rules and a typical demand pattern without violating a given level of service standard. It is dependent upon storage and hydrologic (rainfall/runoff/evaporation) characteristics of the sources, the source facilities, upstream and downstream permitted withdrawals and minimum in-stream flow requirements.For effective operation and management of a water supply system, it is important to have knowledge of water balance of the reservoirs and estimate their safe yield at a certain level of reliability. In this study, to assess water resources potential of existing surface water sources and new catchments and estimate the water balance of the water supply system, the hydrologic simulation model, SWAT (Soil and Water Assessment Tool) was utilized. The model was calibrated and validated successfully. The safe yield and corresponding reliability of reservoirs were estimated using a deterministic water balance model. The results of the water balance analysis and projected water demand were used to assess existing water supply situation and challenges in future. The assessment indicated that the gap between demand and supply at high population growth rate scenario is wide and very critical.To close the gap between the available water supply and the increasing water demand in the study area, utmost attention is needed by the decision making authorities and the management of the water utility to improve performance efficiency of the water supply system by instituting effective water governance and reducing leakage losses.

2020 ◽  
Author(s):  
Jolijn van Engelenburg ◽  
Erik van Slobbe ◽  
Adriaan J. Teuling ◽  
Remko Uijlenhoet ◽  
Petra Hellegers

Abstract. Developments such as climate change and growing demand for drinking water threaten the sustainability of drinking water supply worldwide. To deal with this threat, adaptation of drinking water supply systems is imperative, not only on a global and national scale, but particularly on a local scale. This investigation sought to establish characteristics that describe the sustainability of local drinking water supply. We use an integrated systems approach, describing the local drinking water supply system in terms of hydrological, technical and socio-economic characteristics that determine the sustainability of a local drinking water supply system. Three cases on drinking water supply in the Netherlands are analysed. One case relates to a short-term development, that is the 2018 summer drought, and two concern long-term phenomena, that is, changes in water quality and growth in drinking water demand. The approach taken recognises that next to extreme weather events, socio-economic developments will be among the main drivers of changes in drinking water supply. Effects of pressures associated with, for example, population growth, industrial developments and land use changes, could result in limited water resource availability, deteriorated groundwater quality and growing water demand. To gain a perspective on the case study findings broader than the Dutch context, the sustainability issues identified were paired with global issues concerning sustainable drinking water supply. This resulted in a proposed set of generally applicable sustainability characteristics, each divided into five criteria describing the hydrological, technical and socio-economic sustainability of a local drinking water supply system. Elaboration of these sustainability characteristics and criteria into a sustainability assessment can provide information on the challenges and trade-offs inherent in the sustainable development and management of a local drinking water supply system.


2018 ◽  
Vol 44 ◽  
pp. 00051 ◽  
Author(s):  
Joanna Gwozdziej-Mazur ◽  
Kamil Świętochowski

Water losses in the water supply network pose a continuous challenge for water companies. Already during designing new networks, the designer assumes that the amount of water demand must be increased by a certain percentage (usually by 10% of the total average daily water demand for municipal and industrial purposes) due to the possible occurrence of water losses. Water loss is meant the difference between the amount of water injected into the network and the amount of water used and invoiced, i.e. that brings income for the water supply company. Proper water metering management helps to limit water losses. This paper presents analysis of the water meter management of urban-rural water supply system.


2013 ◽  
Vol 13 (6) ◽  
pp. 1452-1462 ◽  
Author(s):  
H. Benqlilou ◽  
S. Bensaid

Located in a semi-arid region in the south and east of the country, the Moroccan oases are characterized by severe aridity and scarcity of water resources. However, the ancestral populations have shown a major form of adaptation to aridity constraints through the development of knowledge and heuristic expertise on a traditional water supply system called ‘Khettara’. Currently, the effects of climate change on the one hand and the deep social, cultural and economic transformations on the other, have caused the productivity of traditional agriculture to no longer match population needs with progressive vanishing of Khettara as its consequence. A diagnostic study of the situation of oases conducted in the south of Morocco makes it possible to address the socio-economic, environmental and cultural aspects by developing and using a specific methodology to assess fragile ecosystems (DPSIR: Driving Force-Pressure-State-Impact-Response). The main aim of the present work is to provide a methodology allowing the formulation of the required knowledge for the mobilization of traditional water resources techniques such as Khettaras, in order to maintain the national heritage of oases. The modeling formalism of UML (Unified Modeling Language) is borrowed from information technology for the purpose of standardization. The developed methodology enhances these traditional water supply systems by combining traditional and modern techniques to increase their performance in terms of reduced maintenance costs and increased productivity. The developed methodology has been applied to a real case characterized by extreme aridity.


2020 ◽  
Vol 1 (22) ◽  
Author(s):  
Sanel Buljubašić

Freshwater water resources are not inexhaustible [1]. In recent decades, more and more facts point to this statement from the European Charter for Water. Uncontrolled drinking water interventions, losses in water supply and climate change indicate the problem of sufficient quantities of drinking water [2]. Looking at this problem, it is hard to believe that new quantities of drinking water can be produced. The model of integrated water management has been increasingly used in recent years. The application of new technologies in water supply creates conditions for the controlled management of water intakes and losses in water supply. Each water sapply system needs to develop its own model for integrated water management.


Author(s):  

Centre of registry and cadaster provides with the developed DSS information support for management of the Moscow River water supply system since 2009. Information support includes hydrological and water resources analysis, inflow predictions, evaluation of the current state of MRWSS and development of recommendations for water reservoirs management pattern for a next operation term. The developed recommendations are regularly presented at the sessions of interdepartmental working group of the Moscow-Oka river basin authorities. Analysis of current hydrological state is provided on the base of GIS-technologies. Water inflow is calculated by ECOMAG hydrological model describing the full hydrological cycle of the Moscow River watershed. The technique for prediction of water inflow to reservoirs, based on use of a set of weather scenarios, is presented. Water regimes for 5 water reservoirs and downstream branches of the Moscow, Ruza, Ozerna and Istra rivers for a next planning term, are developed with use of VOLPOW water resources system simulation model. Finally the ways of improvement of the discussed DSS for Moscow River water supply system management are proposed.


Resources ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 173 ◽  
Author(s):  
Evangelos Rozos

Meticulously analyzing all contemporaneous conditions and available options before taking operations decisions regarding the management of the urban water resources is a necessary step owing to water scarcity. More often than not, this analysis is challenging because of the uncertainty regarding inflows to the system. The most common approach to account for this uncertainty is to combine the Bayesian decision theory with the dynamic programming optimization method. However, dynamic programming is plagued by the curse of dimensionality, that is, the complexity of the method is proportional to the number of discretized possible system states raised to the power of the number of reservoirs. Furthermore, classical statistics does not consistently represent the stochastic structure of the inflows (see persistence). To avoid these problems, this study will employ an appropriate stochastic model to produce synthetic time-series with long-term persistence, optimize the system employing a network flow programming modelling, and use the optimization results for training a feedforward neural network (FFN). This trained FFN alone can serve as a decision support tool that describes not only reservoir releases but also how to operate the entire water supply system. This methodology is applied in a simplified representation of the Athens water supply system, and the results suggest that the FFN is capable of successfully operating the system according to a predefined operating policy.


2011 ◽  
Vol 14 (1) ◽  
pp. 13-29 ◽  
Author(s):  
Stephen X. Zhang ◽  
Vladan Babovic

Water supply has become a priority for developed and developing nations of the world. Conventional water resources alone cannot meet the growing demand for water in urban cities. Management of the problem is amplified by uncertainty associated with different development strategies. Singapore has limited conventional water resources and progressively architects its water supply system through acquiring and sustaining multiple (alternative) water resources through innovative technologies. The full rationale and merits of such a policy cannot be properly understood based on traditional project valuation methods alone. This paper provides decision support using a real options approach by evaluating innovative water technologies from multiple perspectives under uncertainty. This paper demonstrates that incorporating innovative water technologies into water supply systems can concurrently improve water supply from the financial, political and socioeconomic perspectives. The development of innovative water technologies provides flexibility to the water supply system, and is a fundamental and effective means of risk management. The evaluation of innovative water technologies is based on an integrated real options approach, which provides decision support for architecting water supply systems under uncertainty. The approach gives specific tangible values for the water technologies and complements the general prescriptive Integrated Water Resources Management (IWRM) framework.


2020 ◽  
Author(s):  
Alessio Pugliese ◽  
Mattia Neri ◽  
Armando Brath ◽  
Elena Toth

<p>Complex water optimisation problems represent one of the biggest challenges of the near future due to human and climate impacts. On the one hand, stakeholders in the water supply sector require high-level knowledge of the whole water cycle process at different scales, with the aim to either assess the risk for uncertain future water availability or rely on more analytic approaches for decision making. On the other hand, scientific research produces high quality models, algorithms and schemes capable of solving the water problems, but scientists often struggle when it comes to deploy tools that deliver their research outcomes to stakeholders and decision makers that ultimately will use them. The principal goal of this project is to fill the gap between the development of innovative research methodologies and their practical usability in the real world. We present “RApp”, a web-based application written purely in R within the Shiny framework and developed in collaboration with the water supply company Romagna Acque SpA. RApp simulates and visualizes the behavior of the reservoir that sustains the drinking water supply system of the Romagna region, Italy, in order to support its optimal management. Reservoir simulations are obtained connecting, through a unique and site-specific modelling chain, the inflows from the upstream catchments, the functioning of the reservoir, the potential of the treatment plant and the water demand. The optimized monthly-based management rules were obtained off-line, through a multi-objective optimization algorithm by maximizing the water yields and, at the same time, minimizing the occurrence of water outages during drought periods. The RApp user can produce quick reports of the past and expected reservoir yields and stored volumes, in terms of either graphical or table outputs, as a function of different initial and boundary conditions provided by the users, such as the initial stored volume, the expected inflows, the adoption of optimized or user-defined management rules, the occurrence of an abrupt change in the water demand, thus, allowing stakeholders to explore the impact of different scenarios and management options. For developing the tool, a very close interaction between the research group and the stakeholders was required, and is still ongoing, in order to define and then expand the functionalities of the software that are most needed for its practical use.</p>


Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1723
Author(s):  
Farzad Emami ◽  
Manfred Koch

The present study aimed to quantify the future sustainability of a water supply system using dynamically-downscaled regional climate models (RCMs), produced in the South Asia Coordinated Regional Downscaling Experiment (CORDEX) framework. The case study is the Boukan dam, located on the Zarrine River (ZR) of Urmia’s drying lake basin, Iran. Different CORDEX- models were evaluated for model performance in predicting the temperatures and precipitation in the ZR basin (ZRB). The climate output of the most suitable climate model under the RCP45 and RCP85 scenarios was then bias-corrected for three 19-year-long future periods (2030, 2050, and 2080), and employed as input to the Soil and Water Assessment Tool (SWAT) river basin hydrologic model to simulate future Boukan reservoir inflows. Subsequently, the reservoir operation/water demands in the ZRB were modeled using the MODSIM water management tool for two water demand scenarios, i.e., WDcurrent and WDrecom, which represent the current and the more sustainable water demand scenarios, respectively. The reliability of the dam’s water supply for different water uses in the study area was then investigated by computing the supply/demand ratio (SDR). The results showed that, although the SDRs for the WDrecom were generally higher than that of the WDcurrent, the SDRs were all <1, i.e., future water deficits still prevailed. Finally, the performance of the water supply system was evaluated by means of risk, reliability, resiliency, vulnerability, and maximum deficit indices, and the combination of the indices to estimate the Sustainability Group Index (SGI). The findings indicated that, compared to the historical period for both the water demand scenarios, WDcurrent and WDrecom, the average SGI of each RCP would be decreased significantly, particularly, for the more extreme RCP85 scenario. However, as expected, the SGI decrease for the WDrecom was less than that of the WDcurrent, indicating the advantage of implementing this more sustainable water demand scenario.


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