chapter  7
22 Pages

Water use and conservation

WithAlfredo Fernández-González

The increase in human population and the rapid expansion of urban infrastructure have negatively impacted the hydrologic cycle. As societies become more affluent and their lifestyles continue to evolve, humans around the globe are now striving for additional comfort which demands an abundance of available resources, one of which is water. The extraction of natural resources and the mass production of industrial products result in large amounts of chemical discharge that affect the quality of surface and groundwater. Furthermore, the expansion of urban infrastructure is swallowing agricultural land, wiping out forests, and confining water streams. Impermeable, human-made surfaces also redirect natural flows of both surface and groundwater. As a result, urban areas are dealing with increased storm water runoff that is often times poorly managed, thus accentuating water pollution, urban heat island, the out-migration of local species, and an overall impairment of local ecosystems. The increase in impermeable surfaces is also a trigger for accelerated erosion and sedimentation. Impermeable materials used for construction and the paving of roads reduce groundwater infiltration and therefore have an impact on plant life. These relationships, illustrated in Figure 7.1, directly influence the natural hydrologic cycle. As a way to reduce the negative impacts of urbanization, the concept of integrated site and

building water management (ISBWM) was developed by mimicking the basis of the hydrologic cycle. ISBWMuses a series of onsite strategies that complement prudent decisions of water usage in daily human activities. The systems and strategies employed by the ISBWM approach can be applied to an

individual site or to a series of sites in a neighborhood or building tract to takemaximumadvantage of all viable water harvesting and treatment sources to minimize the dependence on municipal, centralized water supply systems. The harvested water resources may be used for a variety of purposes, such as irrigation of landscaped areas through digitally controlled, high-efficiency systems, cooling tower make-up, and toilet flushing. ISBWM strategies, along with other advanced principles of onsite water treatment, can help reduce the water footprint in urban areas and restore the natural balance of local ecosystems.