Description: To support sustainable long-term developments and minimize urban sprawl, Low Impact Development (LID) practices have been highlighted for a long time. They are useful, but understanding on LID practices and broadening the LID applications among practitioners is another important task. The main purpose of this study is to understand local professionals’ perceptions on different LID techniques and awareness on their benefits, while also gathering opinions on barriers and incentives. An online survey was delivered to 91 recipients, a diverse pool of stakeholders involved in the Energy Corridor District (ECD) area in Houston, Texas. The majority of the respondents answered that they were familiar with LID. The techniques that have been applied to a larger extent are Detention Ponds and Bioswales. When asked about applying techniques in the future, Retention Ponds, Rain Gardens, Bioswales, and Detention Ponds are highly probable items. Decision-makers identified the major barriers as being the lack of incentives for their application, lack of knowledge of the client, and lack of knowledge of the development team. Education programs would be the most successful incentive, followed by financial incentives and innovations in policy systems. Urban planners have the most expertise in LID practices, followed by architects/landscape architects, while developers were found not to be very familiar with the concepts. This study understands the current and practical opinions about LID from the decision-makers. Different groups understand the importance of education and identified a major barrier as the lack of policy instruments. Some innovation in regulations may elevate proper LID practices.

Description: It once seemed that all water managers had to do was to develop and manage infrastructure necessary to convert the natural spatial and temporal distributions of water and its quality to that desired by we humans at acceptable levels of reliability and cost. We are increasingly learning there are limits to achieving such goals, and the consequences can impact just about every component in our economy and society. We’re having to conserve, treat, reuse, find alternatives for and generally get smarter about how we develop and manage our natural resources. Furthermore, we must do it in a political environment of conflicting stakeholder expectations and in ways that minimize the damage to our natural environment as well. No one wants their behavior or life style to contribute to an environment of climatic extremes and regional conflicts that are outside the ranges we and our ecosystems can thrive, or even survive. If we who are in the business of developing and applying models for identifying and evaluating ways of improving how we plan, design, and operate water resources infrastructure systems do not address these broader global environmental and social issues, even partially, and in ways that lead to beneficial impacts, and reduced risks to health and economic security risks, what’s our value? Our literature, including this journal, is full of novel and often useful modeling approaches for identifying and evaluating alternative environmental resource systems designs, plans and policies. Is this enough? This paper addresses ways we might, and in my opinion should, as a discipline, extend our planning and management modeling expertise to address a wider range of societal concerns that stem from the impact water has on almost all human activities. How can we better provide and manage water to better serve society? In short how can we water systems analysts, planners and managers better serve humankind as we manage a critical resource everyone and every economy needs?

Description: The timely repair of City Water Distribution System, a basic guarantee for the life of city residents, requires a reasonable supervision area partition of the City Water Distribution Network (CWDN). In this paper, a graph-theoretic and multi-objective approach for the partition of CWDN is presented. The proposed framework is mainly based on rescue distance and extreme workload of the same area. The rescue distance is expressed by effective distance, which is calculated by the adjustment of straight line distance and seeking smallest value. Extreme workload refers to the average importance of failure nodes belonging to a same crew and needing to be placed in balance. The node importance is coupled with node function importance and node structure importance, and they are calculated using knowledge of Graph Theory. This approach can finish the emergency repair scope partition quickly and easily since it does not rely on precise hydraulic simulation which requires complex calibration processes and computation, while remaining meaningful from a physical and topological point of view. The method is also applied to the analysis of a CWDN and successfully tested, with the result that there emerged a 7.83% decrease of the rescue distance. In addition, the balance of extreme workload was found to be three times higher than the previous.

Description: Transverse mixing coefficient (TMC) is one of the key factors in the modelling of lateral dispersion of pollutants. Several researchers have attempted to estimate this coefficient using various models. However, robust equations that can accurately estimate lateral mixing in both straight and meandering streams are still required. In this study, novel formulae were developed using the hydraulic and geometric parameters of rivers. The multiple linear regression (MLR), genetic programming based symbolic regression (GPSR) and dimensionless parameters were used for this purpose. Two extensive data sets including data from straight channels/streams and meandering ones were employed to develop the formulae. The main advantage of the developed formula for meandering streams is proper consideration of the effects of aspect ratio, friction, and sinuosity. The formulae performances were then compared quantitatively with those of existing ones using accuracy metrics such as RMSE (Root Mean Square Error). The results illustrated that the proposed formulae outperform others in terms of accuracy and can be used for estimating TMC in straight and meandering streams. In addition, the comparison of MLR and GPSR models showed that the latter is marginally more accurate than MLR specially in meandering streams. However, the MLR models presented a more justifiable relationship between the TMC and governing dimensionless parameters. The main advantages of the presented formulae are that they are more accurate than previous models, can be used in both meandering and straight streams; and can be easily implemented in numerical models to estimate the pollutant concentration and mixing length.

Description: The global climate is changing and altering the hydrologic cycle that results in (i) reduction of water supply; (ii) increase in frequency and magnitude of flood and drought events; (iii) damage to the shoreline areas; (iv) increase in irrigation water use; (v) decrease in quality of all freshwater sources; and (vi) increase in functional and operational requirements for the existing water infrastructure. The paper provides the review of water resources management challenges posed by the climate change. In order to provide guidance for including climate change impacts into water management studies, a generic approach is detailed for potential implementation in practice. Methods for selecting global climate models and emission scenarios, followed by bias correction and downscaling are discussed. The paper ends with the description of one practical example, IDF_CC , a web based tool for updating intensity duration frequency curves under changing climate. The tool is designed in response to real needs of water engineering practice and has been in use in Canada since early 2015.

Description: Evolutionary algorithms are used widely in optimization studies on water distribution networks. The optimization algorithms use simulation models that analyse the networks under various operating conditions. The solution process typically involves cost minimization along with reliability constraints that ensure reasonably satisfactory performance under abnormal operating conditions also. Flow entropy has been employed previously as a surrogate reliability measure. While a body of work exists for a single operating condition under steady state conditions, the effectiveness of flow entropy for systems with multiple operating conditions has received very little attention. This paper describes a multi-objective genetic algorithm that maximizes the flow entropy under multiple operating conditions for any given network. The new methodology proposed is consistent with the maximum entropy formalism that requires active consideration of all the relevant information. Furthermore, an alternative but equivalent flow entropy model that emphasizes the relative uniformity of the nodal demands is described. The flow entropy of water distribution networks under multiple operating conditions is discussed with reference to the joint entropy of multiple probability spaces, which provides the theoretical foundation for the optimization methodology proposed. Besides the rationale, results are included that show that the most robust or failure-tolerant solutions are achieved by maximizing the sum of the entropies.

Description: A simulation-optimization framework is presented for reliability-based optimal sizing, operation, and water allocation in the Bashar-to-Zohreh inter-basin water transfer project. The problem was formulated as a mixed integer nonlinear program (MINLP), for which two solution approaches were tested, including gradient-based nonlinear programming and simulation-optimization (SO). The SO framework linked the water evaluation and planning system (WEAP) simulation module, benefiting from fast, single-period linear programming, to the multi-objective particle swarm optimization (MOPSO) for multiperiod optimization. The objective functions were minimizing the sizes of the project’s infrastructures and maximizing the reliability of supplying water to agricultural lands. The combination of nonlinear programming and the branch-and-bound algorithm was not able to solve the resulting MINLP. The results of the MOPSO-WEAP framework indicated that the project can supply water for land development in the Dehdasht and Choram agricultural plains, located in the less developed Kohgiluye and Boyer-Ahmad Province of Iran at an acceptable reliability level. For example, for one of the Pareto solutions found corresponding to maximum land development (30,000 ha), an average volume of 237 million cubic meter (MCM) is transferred annually at a 73.2% reliability level with average sizes of water transfer and storage elements. Further, design-operation and hydropower scenarios were also evaluated, and the Pareto solutions were obtained.

Description: Leak detection and localization in water pipeline networks is of paramount importance to industry, especially in regions where water is scarce. In this paper, we present a novel multi-modal and multi-scale approach for leak detection and localization in water pipeline networks, in which pressure measurements at various points on the network are used to localize the pipe segment in which the leak is occurring, and then the vibration sensors are used to localize the leak within this segment. In some situations where the complete pipeline model is not available, pressure data alone may not be effective in localizing the leak. However, in such a situation, by supplementing pressure data with vibration data, the leak can be localized, as these additional data are easier to acquire at arbitrary points, since vibration sensors are non-invasive. In order to validate the effectiveness of the approach that needs both pressure and vibration data, we simulate the pipeline model using EPANET that includes models for flow and pressure at various points on the pipeline, then integrate the vibration model with it in MATLAB, since EPNAET does not include models for vibration measurements. A case study of a pipeline network is considered, and the proposed scheme is used to detect and localize the leak. Extensive simulation results show the effectiveness of the proposed scheme in providing accurate leak detection and localization.

Description: The purpose of this study is to evaluate Gharanghu multi-purpose reservoir system (East Azerbaijan, Iran) using efficiency indexes (EIs) affected by climate change. At first, the effects of climate change on inflow to the reservoir, as well as changes in the demand volume over a time interval of 30 years (2040–2069) are reviewed. Simulation results show that inflow to the reservoir is decreased in climate change interval compared to the baseline interval (1971–2000), so that comparison of long-term average monthly inflow to the reservoir in climate change interval is reduced about 25% compared to the baseline. Also, water demand in climate change interval will increase, namely volume of water demand for agricultural, drinking and industrial, and environmental in climate change interval is expected to increase by 20%. The simulation results of the water evaluation and planning (WEAP) model is used to determine EIs of multi-purpose reservoir system. Next, three scenarios of water supply for climate change interval are introduced to WEAP model, keeping variable of parameter related to water demand volume (based on different percentages of supply) and keeping constant of the parameter related to the volume of inflow to the reservoir. Results show that system EIs in climate change interval will have a disadvantage compared to the baseline. So that, reliability, vulnerability, resiliency and flexibility indexes in climate change interval based on 100% of water supply compared to the baseline will decrease 18%, increase 150%, decrease 33%, and decrease 47%, respectively. These indexes based on 85% of supply compared to the baseline will decrease 12%, increase 75%, decrease 30%, and decrease 39%, respectively. Also, those based on 70% of supply compared to the baseline will decrease 1%, will be without change, decrease 18%, and decrease 18%, respectively. Changes in indexes in future interval indicate the need to manage water resource development projects in the basin.