Journal of water supply: research and technology. Aqua 

About: Journal of water supply: research and technology. Aqua is an academic journal published by UWA Publishing. The journal publishes majorly in the area(s): Environmental science & Chemistry. It has an ISSN identifier of 1605-3974. Over the lifetime, 36 publications have been published receiving 32 citations.

A combined model based on sparrow search optimized BP neural network and Markov chain for precipitation prediction in Zhengzhou City, China

Abstract: Simulation and prediction of precipitation time series changes are important for revealing global climate change patterns and understanding surface hydrological processes. However, precipitation is influenced by a variety of factors together, showing the characteristics of nonlinear variation patterns. Given that backpropagation (BP) neural network has a strong mapping ability for nonlinear fitting, we consider using BP neural network for precipitation prediction, then use Sparrow Search Algorithm (SSA) to optimize BP network initial threshold and weight information to improve the efficiency of precipitation prediction. To further enhance model predictive performance, the Markov model is employed to predict the residual series of the SSA-BP model, so as to finally construct a combined SSA-BP-Markov model of precipitation. In this paper, the model is used to simulate the rainfall prediction in Zhengzhou City, Henan Province, China, and to compare and analyze with the other traditional models. The empirical prediction results show that the SSA-BP-Markov model is more accurate and the convergence of the algorithm is better. The model provides a new way of thinking for precipitation prediction and is also useful for predicting precipitation in other regions.

Fuzzy logic-based integrated performance evaluation of a water distribution network

Abstract: A water distribution network (WDN) is an essential component of an urban water supply scheme to deliver safe and adequate water to consumers under various operational conditions. This study focuses on the performance evaluation of an urban WDN using fuzzy logic-based aggregation of reliability, resilience, and vulnerability indices. To assess the individual performance indicators, this study advocates the pressure-dependent analysis (PDA) for the hydraulic simulation. Furthermore, it advocates a fuzzy rule-based aggregated performance index (API) that will deliver the outcome in linguistic form and help the decision-maker to prioritize the maintenance of the WDN. The proposed method is illustrated with the help of a real-time WDN for part of Dire Dawa city in Ethiopia. It has been found that the API values for this network are 0.721 and 0.624, respectively, under normal and abnormal conditions, which are just satisfactory. It has been noticed that nodes J4, J44, J47, and J49 are critical from the overall low API. Efforts should be made to improve the hydraulic and residual chlorine conditions at these nodes to increase the API. It is felt that such a methodology will help the decision-makers in improving the performance of an existing urban WDN.

Integrating a GIS-based approach and a SWAT model to identify potential suitable sites for rainwater harvesting in Rwanda

Abstract: The increasing demand of water results in the overexploitation of water resources. This situation calls for more effective water management alternatives including rainwater harvesting (RWH) systems. Due to the lack of biophysical data and infrastructure, the identification of suitable sites for various RWH systems is a challenging issue. However, integrating geospatial analysis and modeling approaches has become a promising tool to identify suitable sites for RWH. Thus, this study aimed at identifying suitable sites for RWH in the Nyabugogo catchment located in Rwanda by integrating a geo-information-based multi-criteria decision-making (MCDM) and SWAT (Soil and Water Assessment Tool) model. Moreover, the sediment yield was compared to the soil erosion evaluated using the Revised Universal Soil Loss Equation (RUSLE) owing to the lack of sediment concentration measured data. The results revealed that about 4.8 and 16.35% of the study area are classified as highly suitable and suitable areas for RWH, respectively. Around 6% of the study area (98.5 km2) was found to be suitable for farm ponds, whereas 1.6% (26.1 km2) suitable for check dams, and 25.9% (423 km2) suitable for bench terraces. Among 50 proposed sites for the RWH structures, 29 are located in the most suitable area for RWH. The results implicated that the surface runoff, sediment yield, and topography are essential factors in identifying the suitability of RWH areas. It is concluded that the integrated geospatial and MCDM techniques provide a useful and efficient method for planning RWH at a basin scale in the study area.

Quantity–quality-based water allocation programming in a reservoir–river system

Abstract: Simulation–optimization approaches are useful methods for the assessment of water resource engineering plans and finding the best management policy at the watershed scale. In this study, to find the optimum operation for a reservoir with the purpose of satisfying water demands while meeting the water quantity and quality criteria, a generic reservoir and river basin simulation model (MODSIM) is coupled with the particle swarm optimization (PSO) algorithm leading to construct the PSO–MODSIM model. With the decision variables of the reservoir's monthly releases, the objective function is to maximize the supply for downstream demands while keeping the electrical conductivity (EC) in the river flow lower than a predefined level at the downstream checkpoint, which is a function of the EC in the agricultural return flows. Moreover, a safe flow rate is defined in which the streamflow should not exceed at the checkpoint resulting in mitigation of the submerging lands damage. Results obtained by the PSO–MODSIM model indicate the ability of the proposed simulation–optimization approach for solving the problem of optimal quantity–quality-based water allocation in a reservoir–river system. For instance, the EC at the checkpoint is decreased by 61% in the optimum reservoir operation state comparing the present situation, whereas the municipal and environmental demands are fully met and the agricultural demands are supplied with a desirable reliability satisfaction level.

Factors influencing economic benefit of rainwater harvesting: an empirical analysis

Abstract: This study examines key factors influencing the economic benefit of rainwater harvesting on the household at the Mongla Upazila in the Bagerhat district of coastal Bangladesh. The household survey questionnaire was used to collect primary data from 1040 households. The Ordinary Least Square (OLS) regression analysis was applied to understand the relationship between economic benefit and factors that can affect economic benefit in the household. The empirical result shows that income (1.103**), storage capacity (0.574***), water price (32708.9***), age of rainwater harvesting (100.083***), and total cost (1.627***) positively impact economic benefit while the number of children (35.531**) has a negative relationship. The finding confirms the validity of statistical hypotheses. In addition, heterogeneity analysis was employed to test the model's strength and robustness check to validate the structural function and efficiency of the regression model. The finding concludes with policy recommendations, especially for rain-intensive countries that focus on (i) formulating and implementing rainwater harvesting policy; (ii) integrating rainwater harvesting as a tool for poverty reduction and achieving sustainable development goals; (iii) minimizing mismanagement of (rain) water that causes floods; (iv) initiate programme and take necessary steps for providing financial and non-financial incentive for rainwater harvesting in commercial, and non-commercial building.