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 precipitation events, such as rainwater and snowmelt, from percolating into the ground. These surfaces include roads, sidewalks, driveways, parking lots, swimming pools 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 because the Earth’s climate is showing signs of a shift, becoming warmer, with more 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:
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
Environmental Protection Agency
Natural Processes of Groundwater and Surface Water Interaction
(http://pubs.usgs.gov/circ/circ1139/htdocs/natural_processes_of_ground.htm)
This U.S. Geological Services Web site explains the hydrologic cycle.
Managing Wet Weather with Green Infrastructure
(http://cfpub.epa.gov/npdes/home.cfm?program_id=298)
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
(http://www.lowimpactdevelopment.org/)
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
(http://www.sustainablesites.org/hydrology/)
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.
Disclaimer: Links to non-federal organizations found at this site are provided solely as a service to our users. These links do not constitute an endorsement of these organizations or their programs by CDC or the federal government, and none should be inferred. CDC is not responsible for the content of the individual organization Web pages found at these links.