The hydrologic cycle continuously cycles water through precipitation, runoff, soil percolation, evaporation, and condensation. Precipitation patterns vary naturally from year to year and over decades and centuries. The challenge for water suppliers is to determine how the hydrologic cycle provides water to service areas, in what quantities, and with what level of reliability (Bloetscher and Muñiz 2006). Water supply reliability and sustainability are closely linked. Water supply sustainability has been defined by the Water Resources Division of the American Water Works Association (AWWA) as “the planning, development, and management of water resources to provide an adequate and reliable supply of water with a quality suitable to meet the economic, environmental and social needs for current and future generations.” Murley (2006) added “in a manner that will not diminish the ability of future generations to meet their needs.”
Since the production and delivery of drinking water and the treatment of wastewater are recognized as vital functions of society, long-term viability and development of water supplies is required to sustain long-term economic viability and public health, despite competing interests that may include agriculture, ecosystems, recreation, and industrial demands. Unfortunately, there are many examples where water supplies in a given basin are overcommitted or where, as a result of changing precipitation and temperature patterns, a reduction in the water supply “pie” results. Prioritizing water use under such scenarios should include identifying needs so that lower-quality waters can be prioritized for lower-quality use needs like agriculture.
However, ecosystem water supply needs have historically been ignored, as has their intrinsic economic value. As a result, large-scale clearing and filling of coastal wetlands, bayous, and mangroves has subjected coastal areas to damage from storm events and sea level rise. Securing reliable water supplies for future generations is important in the face of changes in climatic patterns. Water supplies can become more reliable and sustainable through a comprehensive approach to water planning that includes using alternative water sources and planning future infrastructure needs with long-term trends in mind. Systems must be adaptable to changing conditions, because researchers expect that long-term trends will be altered as a result of climate impacts…
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