Water Distribution Model Research Articles

Modeling and Optimization of Water Distribution in Mineral Processing considering Water Cost and Recycled Water.

Reducing mineral processing water costs and freshwater consumption is a challenging task in the mineral processing water distribution (MPWD). The work presented in this paper focuses on two aspects of the MPWD optimization model and the MPWD optimization method. To achieve MPWD optimization effectively, a nonlinear constrained multiobjective model is built. The problem is formulated with two objectives of minimizing the mineral processing water costs and maximizing the amount of recycled water. In this paper, an optimization method named enhancing the multiobjective artificial bee colony (EMOABC) algorithm is proposed to solve this model. The EMOABC algorithm uses four strategies to obtain the Pareto-optimal solutions and to achieve the MPWD optimal solutions. With the three benchmark functions, the EMOABC algorithm outperforms the other two widely used algorithms in solving complex multiobjective optimization problems. The EMOABC algorithm is then applied to two cases. Results have shown that the proposed algorithm has the ability to solve the MPWD optimization model. The developed model and the proposed algorithm provide decision support for the actual MPWD problem.

Stress-Testing Framework for Urban Water Systems: A Source to Tap Approach for Stochastic Resilience Assessment

Optimizing the design and operation of an Urban Water System (UWS) faces significant challenges over its lifespan to account for the uncertainties of important stressors that arise from population growth rates, climate change factors, or shifting demand patterns. The analysis of a UWS’s performance across interdependent subsystems benefits from a multi-model approach where different designs are tested against a variety of metrics and in different times scales for each subsystem. In this work, we present a stress-testing framework for UWSs that assesses the system’s resilience, i.e., the degree to which a UWS continues to perform under progressively increasing disturbance (deviation from normal operating conditions). The framework is underpinned by a modeling chain that covers the entire water cycle, in a source-to-tap manner, coupling a water resources management model, a hydraulic water distribution model, and a water demand generation model. An additional stochastic simulation module enables the representation and modeling of uncertainty throughout the water cycle. We demonstrate the framework by “stress-testing” a synthetic UWS case study with an ensemble of scenarios whose parameters are stochastically changing within the UWS simulation timeframe and quantify the uncertainty in the estimation of the system’s resilience.

Water distribution and transport-kinetics model in fresh cement-based mixtures containing superabsorbent polymers based on 1H low-field NMR

Superabsorbent polymer (SAP) can be used as a curing agent in cement-based materials. Due to the replenish of humidity decline caused by the continuous consumption of water, the SAPs will contribute substantially to mitigating the shrinkage and obtaining the expected curing efficiency. Many studies have described the characteristics of water immigration in SAP-modified cement-based mixtures, but the travelled distance, volume, and transport-kinetics model of the water released from the SAP in cement-based materials still need to be investigated in detail. The paper focuses on the sustained water distribution of SAP at early-age cement-based mixtures. The swelling characteristics of SAP in different liquids and the water transport kinetics in hydrating cement-based mixtures were studied based on the ion concentration test and low-field Nuclear Magnetic Resonance (NMR) measurement. The results show that when SAP is in contact with water or cement filtrate, the exchangeable cations on the SAP structure will move freely to the solution and rapidly exchange with the metal cations in the solution within a few minutes (about 5 min). The most predominant form of water in fresh cement-based mixtures was the absorbed water (adsorbed on the surface of particles or in pores). Part of the adsorbed water or small capillary water on the surface of cement particles was consumed for hydration. The incorporation of SAP can prevent bleeding and segregation and promote the 28-day compressive strength of cement-based materials under the same total w/c ratio. Finally, the water-transport model in fresh cement-based mixtures was established and verified.

IRRIGATION UNIFORMITY OPTIMISATION OF A MINI-CENTRE PIVOT SYSTEM

In El Oued, southern Algeria, the traditional Mini-Centre Pivot System (MCPS) is widely used for the irrigation of agricultural crops, and its use has been growing continuously. However, these systems have a constant nozzle diameter along the lateral pipe, which affects productivity directly, besides decreasing both the quantity and quality of agricultural products by irrigation heterogeneity. Therefore, optimising the design of the MCPS nozzles is linked strongly to the desired uniform irrigation. This study aims to determine the optimal configuration of nozzles for high irrigation uniformity. To achieve this goal, a genetic algorithm was used for maximising the uniformity of MCPS-mediated irrigation. The optimisation is carried out according to water distribution modelling, calculation of the Heermann and Hein uniformity coefficient (CUH), and existing nozzle diameters. To verify the accuracy of the proposed model, three existing MCPS (60 m, 50 m, and 46 m in length) are investigated experimentally. The developed code findings in terms of CUH are in agreement with those obtained by experimental tests. The analysis indicated that the nozzle diameter should vary from 5 to 15 mm along the lateral pipe. In these optimal conditions, the CUH was improved by 29.77%, 33.99%, and 19.36%, respectively, for the existing 60, 50, and 46 m irrigation systems. The most obvious findings to emerge from this study is that using a genetic algorithm to optimise the design based on the nozzle size improves water application uniformity by more than 19% in terms of the CUH.

Effective well management using the J100 framework and methodology

AbstractWell rehabilitation and replacement are critical functions and activities where water utilities can benefit from rational decision‐support frameworks and tools that enable them to navigate the complex range of technical, managerial, financial, and public/environmental health considerations involved. Based on this industry viewpoint and need, a 15‐variable risk‐based prioritization framework and methodology patterned after the ANSI/AWWA J100 Risk and Resilience Management Standard was therefore developed and tested on a relatively large water system in California. The framework draws from a wide range of information sources and analytical approaches, including existing drinking water source assessments, public documents concerning the health of groundwater basins and aquifers, the results of recently conducted climate change studies, and water distribution modeling to balance the three principal dimensions of the J100 methodology (threat, vulnerability, and consequence). The new tool is expected to help optimize routine monitoring and inspections, as well as enhance the scheduling and implementation of rehabilitation and replacement activities through the deeper and more holistic understanding it provides around regional, site and facility, and water distribution operational and systems engineering factors.

Establishing a Range of Extreme Precipitation Estimates in California for Planning in the Face of Climate Change

AbstractFor California water resource planning in the face of climate change, hydrological and water distribution models require inputs of high spatial– and temporal–resolution temperature and prec...

Modeling of Water Distribution under Center Pivot Irrigation Technique

AbstractAiming to quantify the impacts of the center pivot irrigation technique on soil moisture dynamics and to improve irrigation crop water needs, a mathematical model was developed to estimate ...

A New Model Predictive Control Method for Eliminating Hydraulic Oscillation and Dynamic Hydraulic Imbalance in a Complex Chilled Water System

To enhance the energy performance of a central air-conditioning system, an effective control method for the chilled water system is always essential. However, it is a real challenge to distribute exact cooling energy to multiple terminal units in different floors via a complex chilled water network. To mitigate hydraulic imbalance in a complex chilled water system, many throttle valves and variable-speed pumps are installed, which are usually regulated by PID-based controllers. Due to the severe hydraulic coupling among the valves and pumps, the hydraulic oscillation phenomena often occur while using those feedback-based controllers. Based on a data-calibrated water distribution model which can accurately predict the hydraulic behaviors of a chilled water system, a new Model Predictive Control (MPC) method is proposed in this study. The proposed method is validated by a real-life chilled water system in a 22-floor hotel. By the proposed method, the valves and pumps can be regulated safely without any hydraulic oscillations. Simultaneously, the hydraulic imbalance among different floors is also eliminated, which can save 23.3% electricity consumption of the pumps.

Experimental Study on the Behaviour of Seismic Actions on a Flexible Glass-Reinforced Plastic Structure Used in Water Transport Pipes.

This article presents the experimental results obtained by the testing an experimental model of water distribution which is flexible and above-head mounted on a seismic platform, and their validation in a theoretical manner, but also by the Finite Element Method, using the ANSYS simulation program. This type of system shown by the experimental model is desired to be used in practice not only in seismic areas, but also in the areas of heavy road transport, landslides, etc. thorugh the use thereof in the most stressed points of the network (hearth entry/exit, before/after an elbow, etc.) but also on long routes, at optimal distances. The results achieved are related to glass- reinforced plastic (GRP) pipes with a nominal diameter DN = 250 mm, but conclusions may be drawn starting from these to help future research where the mass of the earth is desired to be taken into account. The present results are comprehensive for buried pipes operated dynamically or seismically at low-medium intensity, as this type of earthquake occurs more and more often in Europe. The experimental tests in this article do not have the characteristics necessary for a high intensity seismic action (above 5° Richter).

A Semi-Analytical Solution for Countercurrent Spontaneous Imbibition in Water-Wet Fractured Reservoirs

Countercurrent spontaneous imbibition (SI) is an important flow mechanism for oil recovery in fractured reservoirs during waterflooding. SI plays a key role in the mobilization of oil in the matrix because it facilitates water infiltration by capillarity even when the matrix permeability is low, which limits fluid transport by advection. However, the modeling of SI in fractured media under dynamic conditions has been insufficiently studied. Most imbibition models assume conventional exponential functions and empirical constants based on experimental results of oil recovery under static conditions. Thus, the modeling of water distribution in the fracture and the matrix has been ignored which may lead to incorrect estimates of the efficiency of countercurrent SI to recover oil. Using the classic fractional flow equation, we present a semi-analytical solution to model countercurrent SI in a water-wet fractured medium by including a transfer function to account for continuous fluid exchange between the fracture and the matrix. The model is numerically solved using finite differences by including an effective imbibition time as a function of water advance in the fracture, which overcomes the difficulty of solving iterative numerical summations as shown in other imbibition models. The novelty of the presented solution is that it enables the modeling of water infiltration in the matrix under dynamic conditions. We verified the semi-analytical model against 2D numerical simulations and validated against experimental data to demonstrate that the model accurately predicts oil recovery and water infiltration in the matrix.

Cyber-Physical Stress-Testing Platform for Water Distribution Networks

The water sector is facing emerging challenges, as cyber-physical threats target Supervisory Control and Data Acquisition (SCADA) systems of water utilities. A cyber-physical stress-testing platform is presented in this work, named RISKNOUGHT, which is able to model water distribution networks as cyber-physical systems, simulating the information flow of the cyber layer and the feedback interactions with the physical processes under control. RISKNOUGHT utilizes an EPANET-based solver for the physical process and a customizable network model for the SCADA system, capable of implementing complex control logic schemes within a simulation. The platform enables the development of composite cyber-physical attacks on various elements of the SCADA, including sensors, actuators, and PLCs, assessing the impact they have on the hydraulic response of the distribution network and the level of service. The platform is tested on a proof-of-concept benchmark network with promising results that demonstrate that the platform can form an innovative cyber-physical tool to support strategic planning and risk management.

Effects of Demand, Mixing Fraction, and Rate Coefficient Uncertainty on Water Quality Models

AbstractThe effects uncertainty on water quality predictions by the free water distribution modeling software created by the US Environment Protection Agency (EPANET2) are assessed using both desig...

Study on Unsteady Flow Based on Optimized Water Distribution Model in Irrigation District

The canal delivery system is the main infrastructure of agricultural irrigation. The efficiency of water use in agriculture can be achieved by mastering the dynamic process of unsteady flow in the channel. In this study, an unsteady flow model for the calculation of the water flow transition information of the river channel during the water distribution process was established, based on the water distribution scheme given by the backtracking-search algorithm (BSA). This model was more suitable for areas with inefficient channel systems. The research areas included the main irrigation channels in Xiying City, which is one of the typical agricultural areas in northwestern China. The scheme obtained by optimal solution proposed for Xiying Irrigation District was feasible. According to the results of the flow simulations, the sluice gate calculation correlation could determine the change process of the gate opening of each channel, which provided a basis to realize the modernization of the irrigation area.

Revealing soil‐borne hydrogel effects on soil hydraulic properties using a roughness‐triangular pore space model

AbstractUnderstanding the influence of soil‐borne hydrogels (e.g., bacterial extracellular polymeric substances [EPS] and biofilm or root‐derived mucilage) on soil hydraulic properties is crucial for accurate modeling of flow and transport in porous media. The underlying mechanisms of how hydrogels modify soil physical and hydraulic properties, however, remain unclear. In this study, we applied a roughness‐triangular pore space model (R‐TPSM) to simulate water retention curve and hydraulic conductivity of hydrogel‐affected soils. The model considers the effective soil pore size distribution and physicochemical properties (e.g., surface tension and surface roughness) of soil and soil solution. The modeling results are in good agreement with measured water retention curves and hydraulic conductivity for different textured soils. Comparison of the fitted model parameters between control and hydrogel‐treated soil samples indicates that hydrogels reduce surface tension and shift the effective pore size distribution to a narrower size range. Hydrogels generally increase water retention in the form of adsorptive films and reduce film flow under relatively dry conditions. This study highlights the importance of considering reduced surface tension and mean pore size by hydrogels in changing soil hydraulic properties, which has important implications for accurate modeling of water distribution and flow in the rhizosphere.

Model Performance Indicator of Aging Pipes in a Domestic Water Supply Distribution Network

Aging pipes in the domestic water distribution network have the potential to decrease the quality and quantity of the treated water supplied to the consumers. Therefore, a calibrated water distribution model is helpful to monitor and understand the behaviour of a real water distribution network. However, a comprehensive performance indicator and an integrated method to assess the efficiency of model performance have not been well established in the literature. This study developed a methodology for a model calibration exercise, with consideration of two uncertainty parameters, i.e., Hazen–Williams roughness coefficient of the pipes and Non-Revenue Water (NRW) in each nodal demand. Following this, a statistical color-coded performance indicator was established, based on the Nash–Sutcliffe Efficiency Coefficient (NSEC), the coefficient of determination (R2), the correlation coefficient (r), and the Mean Absolute Error (MAE). The accuracy of the calibrated model was measured by Discrepancy Ratio (DR) analysis. This study concluded that the model performed well when NRW was added to the nodal demand in zone(s) with suspected water loss activities. The suggested Hazen–Williams roughness coefficient for PVC pipes was between 130 and 140 for pipes aged more than 20 years. The threshold error value to determine the accuracy of the simulated model was proposed to be between –0.05 and 0.05.

Multi-objective model of irrigation water distribution based on particle swarm optimization

Developing the high-efficiency agriculture is the strategy of agricultural sustainable development, and rational allocation of irrigation water resources is an important way in improving the efficiency of agricultural resources utilization. In this paper, the particle swarm optimization algorithm is used to optimize the irrigation water distribution schedule. This model focuses on decreasing the leakage loss and increasing allocation efficiency of irrigation water distribution. The transition process verified the rationality of the water distribution scheme and effectively satisfied the actual demand.

Evaluation of groundwater recharge by rice and crop rotation fields in Kumamoto, Japan

Abstract In Kumamoto, Japan, about one million people depend for all their water on groundwater resources. Paddy fields and rice farming in the middle river watershed area make a large contribution to the groundwater recharge. In our research, an environmental measure (artificial flooding for groundwater recharge) conducted by local governments is evaluated. Hydrological measurement was conducted in a paddy plot in the area. A simple model of water distribution was developed on the basis of the field measurement. Then, drought risk in the paddy-field district was estimated using the model and GIS data. The results reveal that the fields with a high percolation rate of more than 30 mm/d result in inefficient use of irrigation water although they have large potential for groundwater recharge. In addition, the water distribution model suggests that environmental measures can increase the risk of water shortage in the paddy-field district due to the farmers' careless use of water.

Water distribution model for center pivot end gun sprinklers

ABSTRACT End gun sprinklers can increase the irrigated area by center pivot irrigation systems without a substantial investment. This study was carried out at the Universidade Federal de Lavras, MG state, Brazil, and aimed to describe and validate a water distribution model for center pivot end gun sprinklers. The gun sprinkler PLONA-RL250®, attached at the end point of a center pivot, was used to evaluate the model in field tests. The sprinkler working conditions considered were nozzle diameters of 14 x 6 mm, working pressure of 292 kPa, and four asymmetric wetted angle adjustments (95 + 20º; 90 + 90º; 60 + 60º; 45 + 45º). These tests were carried out for wind speed lower than 0.9 m s-1. The measured and simulated irrigation depths showed an average absolute difference of 0.65 mm and determination coefficients from 71.55 to 89.37%. Based on the confidence coefficient (c = 0.82) the model can be classified as very good (0.76 ≤ c ≤ 0.85). Sprinkler wetted angle adjustment of 110º (95 + 20º) resulted in uniform water distribution and, for effective radius of throw between 70 to 90% of the gun sprinkler´s radius of throw, this working condition resulted in Christiansen’s uniformity greater than 80%.

Study on Pipe Burst Detection Frame Based on Water Distribution Model and Monitoring System

This paper describes an infrastructure to detect burst events in a water distribution network, which we illustrate using the Guangzhou water distribution system (WDS). We consider three issues: The feasibility and capability of accurate detection, the layout and design of the monitoring infrastructure, and the burst event detection algorithm. Background noise is identified by analyzing the monitored data. A burst event can be accurately detected only when the impact of the burst can be differentiated from the background noise. We hypothesize that there is a minimum pipe diameter below which accurate burst detection is impossible. We found that data from at least two sensors close to the burst event are required to reduce detection errors.

Water distribution modelling of capillary absorption in cementitious materials

Abstract In this paper, a novel capillary absorption model is proposed to investigate the capillary absorption process of cementitious materials. This model mainly consider the influence of tortuosity of the capillary pores of cement paste, which is the key factor affecting the capillary absorption process. The proposed model is verified by the capillary absorption process of paste samples with different water/cement ratios. The absorption height and water content profile of testing samples are measured by X-ray computed tomography. The results show that the proposed capillary absorption model that takes the tortuosity of capillary pores into consideration is suitable for investigating the capillary absorption process of water in cementitious materials.