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Urban heat islands (UHIs) pose a significant challenge in cities worldwide, exacerbating energy use, air pollution, and health risks. This paper reviews the role of water bodies in mitigating UHI effects, which is vital for informed urban planning and climate adaptation. We analyze how water features, particularly when combined with green spaces and strategic urban design, can significantly cool urban environments. The effectiveness of water bodies in reducing temperatures is influenced by their size, shape, surrounding land use, climatic conditions, and vegetation. Empirical research and case studies indicate that larger and well-shaped water bodies, due to their extensive surface area and continuous evaporation, are more effective. Furthermore, the integration of water bodies with green spaces enhances cooling through increased evapotranspiration and shading. This review highlights the strategic placement and design of water bodies within urban landscapes as crucial for maximizing their cooling benefits. By integrating water features with other urban cooling strategies, such as tree planting and expanded greenery, cities can effectively counter UHI effects, leading to more sustainable and resilient urban environments. [ABSTRACT FROM AUTHOR]

The paper describes a procedure for the robust design of water distribution networks which incorporates the uncertainty of nodal water demands and pipe roughness in a multiobjective optimization scheme aimed at minimizing costs and maximizing hydraulic reliability. The methodology begins with a deterministic system design in order to generate a set of optimal networks that serves as the initial population for subsequent multiobjective stochastic design. This approach does not depend on the choice of multiobjective optimizer (for example, a multiobjective genetic algorithm is used here) and can drastically reduce the number of 'stochastic' runs needed for searching robust solutions. A collection of probability density functions based on the [beta] function is introduced and applied to modeling variable uncertainty according to different physical requirements. The approach is tested in a case study involving a real network, illustrating its computational advantages. CE Database subject headings: Stochastic processes; Water distribution systems; Networks; System reliability; Uncertainty principles.

The challenge of water demand representation in water distribution systems is revisited with a brief exploration of the relationship between a pressure-dependent leak and a fixed legitimate demand. Specifically, the idea that a leak can be modeled as an increment to legitimate demand in such a way that it entails an equivalent impact on both water loss and energy consumption is explored. Conversely, the representation of demands as leaks is briefly considered. The effectiveness of pressure reduction and demand curtailment as leak management schemes are compared for a single pipe system. The influence of pipe resistance on this relationship is assessed, suggesting that such schemes are more important in rougher pipes. In general, the notion that leakage and demand analysis/management are two sides of the same coin, and that pressure/demand management is essentially conservation, is put forth. CE Database subject headings: Water demand; Water distribution systems; Leakage.

A conceptual examination of the energy impact of leaks in systems with storage is undertaken. Consideration of how leakage is experienced at the pump is followed by an analysis of how different leakage levels alter energy costs for a rudimentary system with three topological configurations: two with a storage tank located at different points, and one without storage. Additionally, two friction regimes are subsumed in the analysis. EPANET 2 simulations are used to determine system pressures, storage tank levels, energy costs, power consumption, and leakage volumes for all scenarios at live levels of leakage. Leaks increase operating costs in terms of lost water and extra energy consumption for all systems, and when a price pattern is implemented, the financial cost of energy can sometimes be traded off with actual energy consumption. Storage in a system does not guarantee lower energy use relative to direct pumping, and in some cases it may promote higher leakage due to elevated system pressures. The results, though system specific, suggest that the importance of leaks in a system with storage depends on a number of factors, especially the relative locations of system components and the pumping strategy. Thoughtful consideration of the latter can be instrumental in achieving operation that balances financial and energy conservation objectives. To further test key relationships, a representative network is briefly considered. In all cases, the percentage increase in energy cost is greater than percentage leakage when the same pressure requirements are met. DOI: 10.1061/(ASCE)0733-9496(2005)131:2(146) CE Database subject headings: Leakage: Energy consumption: Water storage: Water distribution: Pumped storage.

Leaky distribution systems are costly in terms of lost water, potentially adverse water quality effects, and the energy consumed in supplying the leaks. To characterize the energy effectiveness of a leaky segment in a single pipe, several dimensionless parameters are analytically derived, which relate the leak size and location to its associated energy burden and water loss. The computer program EPANET is used to simulate the energy costs of leaks on representative distribution networks. In particular, analysis is performed to illustrate the influence of total system demand, leak location, and topological complexity. Furthermore, the connection between water loss and energy costs illustrates the potential importance of energy costs when pipes are leaky. The impact of leaks on water age is also evaluated through simulation and via a dimensionless expression relating leak size and location to residence time. DOI: 10.1061/(ASCE)0733-9496(2002)128:6(441) CE Database keywords: Leakage; Water pipes; Costs.

Comments on the article "Energy and Costs of Leaky Pipes: Toward Comprehensive Picture," by Andrew F. Colombo and Bryan W. Karney. Effects of leakage on pumping cost; Equation for pumping cost; Effects of leakage on energy use.