Water Quality

  We expect our water to be safe for drinking, recreation, hygiene, and other uses. Yet human activities related to different land use and land-management practices can have an impact on the water quality of a community.

Most urbanized areas have impervious surfaces that keep rainwater and water from snowmelt from percolating into the ground. These surfaces include roads, sidewalks, driveways, parking lots, swimming pool decks and rooftops. Even turf grass lawns restrict water flow into the ground and actually become nearly as impervious as paved surfaces because of turf grass’s densely-matted root structure. During and after a rainstorm, water rushing off impervious surfaces can be significant. This water is called runoff. Runoff rates could increase in the future in some areas of the world due to more frequent and extreme precipitation.

Runoff can be directly associated with erosion, sediment transport and sedimentary rock formation, flooding, loss of biodiversity, aquifer depletion, and water quality degradation. Water that does percolate into the ground after a precipitation event can carry contaminants from different waste sources like septic tanks, landfills and road runoff, to areas that may pose a risk to the health of people exposed to it.

One of the best ways to protect the water quality of a community is to minimize the disruption of the natural water cycle, also known as the hydrologic cycle-- the continuous movement of water on, above, and below the surface of the Earth. This requires city planners to consider the impact of their land use decisions on the community’s water quality and on human health. Considerations may include a low-impact development approach that would help conserve the natural systems and hydrologic functions of any site by:

• Capturing, cleansing, and reusing water from precipitation events through the integration of building and site design techniques such as greenroofs, porous paving systems, bioswales, bioretention areas, rainwater harvesting, and native landscape systems that are highly absorbent.
• Working towards a sustainable, site-appropriate design that integrates the reuse of wastes and water in a way that protects public health while preserving the integrity of ecological and biological systems.
• Protecting and incorporating natural aquatic systems (such as wetlands and streams) as design elements.
• Preserving natural open space (such as meadows and natural preserves) and minimizing land disturbance.
• Protecting watersheds and water resources through greenfield development practices.

Wastewater Management

Land use decisions related to wastewater management may also affect water quality. Wastewater management deals with collecting, treating, and disposing of wastewater.

EPA WaterSense Partner

CDC is an EPA WaterSense promotional partner and shares EPA’s goals: To use water resources more efficiently to preserve them for future generations and reduce water and wastewater infrastructure costs by reducing unnecessary water consumption.

For more information, refer to the following resources:

Centers for Disease Control and Prevention

• National Center for Environmental Health, Environmental Health Services
  CDC's Environmental Health Services Branch provides training, tools and guidance, and research to help environmental health practitioners prevent foodborne illnesses and outbreaks, protect water, and improve services.
• National Center for Zoonotic, Vector-Borne, and Enteric Diseases, Healthy Water
  The Web site has a variety of topics on water including drinking water; global water, sanitation and hygiene; healthy swimming/recreation water; water-related emergencies and outbreaks; and diseases, contaminants and injuries.

Environmental Protection Agency

• Office of Water
  The Web site provides information on the key goals of the U.S. EPA Office of Water: Clean and safe water; land preservation and restoration; healthy communities and ecosystems; and compliance and environmental stewardship.
• WaterSense
  WaterSense, a partnership program sponsored by the U.S. EPA, makes it easy for Americans to save water and protect the environment.
• Office of Research and Development, Sustainability Program
  The Web site provides one-stop access to the U.S. EPA and related programs and the latest research and activities related to urban sustainability and the built environment; water and ecosystem services; energy, biofuels and climate change; and materials management and human health.

Natural Processes of Groundwater and Surface Water Interaction
This U.S. Geological Services Web site explains the hydrologic cycle.

Managing Wet Weather with Green Infrastructure
Green infrastructure is an approach to wet weather management that is cost-effective, sustainable, and environmentally friendly. Green infrastructure management approaches and technologies infiltrate, evapotranspire, capture and reuse stormwater to maintain or restore natural hydrologies.

Low-Impact Development Center
The Low Impact Development Center is a non-profit organization dedicated to the advancement of Low Impact Development technology. Low Impact Development is a new, comprehensive land planning and engineering design approach with a goal of maintaining and enhancing the pre-development hydrologic regime of urban and developing watersheds.

Sustainable Sites Initiative
Hydrology is a focus area of the Initiative. The Initiative is an interdisciplinary effort by the American Society of Landscape Architects, the Lady Bird Johnson Wildflower Center and the United States Botanic Garden to create voluntary national guidelines and performance benchmarks for sustainable land design, construction and maintenance practices.

Farr, Douglas. Sustainable Urbanism. Jon Wiley & Sons, 2008.
The book includes discussions on stormwater systems, and indoor and outdoor wastewater treatment.

References

Schueler, TR, Holland, HK, editors. Why stormwater matters. The practice of watershed protection: an edited anthology. Article 63. Center for Watershed Protection; Maryland: 2000.

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