This study presents a comprehensive review of the literature on implementation of various decentralized water systems along with centralized systems. The review highlights the benefits provided by these systems as well as various challenges posed associated with them. There are complex interactions involved within the water systems in an urban setting that are multidimensional and span over various aspects of water availability, quality, energy use, environmental, legal, economic, and social sectors. Although there are many economic, environmental, and social benefits associated with decentralized systems, there are some hidden challenges that are generally overlooked by planners and managers; these include the spatial integration of such systems, their energy intensity, social, economic, and environmental viability of these systems. Decisions to implement decentralized water systems require decision makers to consider economic, social, and environmental dimensions conjointly through an appropriate multicriteria decision analysis to select the hybrid water supply combination optimal for the given circumstances. The existing studies and tools are unable to address these factors using an integrated approach. So a holistic framework to evaluate and compare various water supply options in terms of energy use, social, economic, and environmental impacts is required to assess such systems in comprehensive manner. WIREs Water 2015, 2:623–634. doi: 10.1002/wat2.1099 This article is categorized under: Engineering Water > Planning Water Engineering Water > Sustainable Engineering of Water

Groundwater pumping has caused excessive groundwater depletion around the world, yet regulating pumping remains a profound challenge. California uses more groundwater than any other U.S. state, and serves as a microcosm of the adverse effects of pumping felt worldwide—land subsidence, impaired water quality, and damaged ecosystems, all against the looming threat of climate change. The state largely entrusts the control of depletion to the local level. This study uses internationally accepted water resources planning theories systematically to investigate three key aspects of controlling groundwater depletion in California, with an emphasis on local‐level action: (a) making decisions and engaging stakeholders; (b) monitoring groundwater; and (c) using mandatory, fee‐based and voluntary approaches to control groundwater depletion (e.g., pumping restrictions, pumping fees, and education about water conservation, respectively). The methodology used is the social science‐derived technique of content analysis, which involves using a coding scheme to record these three elements in local rules and plans, and State legislation, then analyzing patterns and trends. The study finds that Californian local groundwater managers rarely use, or plan to use, mandatory and fee‐based measures to control groundwater depletion. Most use only voluntary approaches or infrastructure to attempt to reduce depletion, regardless of whether they have more severe groundwater problems, or problems which are more likely to have irreversible adverse effects. The study suggests legal reforms to the local groundwater planning system, drawing upon its empirical findings. Considering the content of these recommendations may also benefit other jurisdictions that use a local groundwater management planning paradigm.

The Sustainable Groundwater Management Act (SGMA) aims to control, for the first time in California's history, the state's significant use and depletion of groundwater. SGMA gives local agencies a high degree of discretion in relation to a new permitting power, but the discretion is a double-edged sword: agencies gain maximum flexibility to tailor their regime to local conditions, yet the statute provides no direction on appropriate components of a groundwater permitting regime. We introduce SGMA and the broader legislative context to its permitting power, and we explain the continuing common law context in which the legislation operates. This information is used as the foundation for a comparative legal analysis of fundamental elements of permitting regimes. We compare a selection of six other south-western permitting regimes established in legislation for areas recognized as requiring intensive management through permitting: "special permitting areas" (SPAs). We find that permitting regimes in south-western SPAs share a structure containing several almost universal elements, although the policy settings that apply to those elements vary widely. The established permitting regimes in the other south-western states' SPAs may inform Californian agencies seeking to use their new permitting power for the first time, as well as water agencies further afield, as to important components of a permitting regime, and the different policy settings that could apply to those components. Californian local agencies, and its Department of Water Resources, which is charged with providing local agencies technical advice, should have regard to these permitting possibilities.

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