PNWWATER 046: Landscaping to Protect Community Water

Fall 2004
PNWWATER 046

Landscaping to Protect Community Water

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Whether you garden on a balcony in the urban core, or on land in rural America, landscape and gardening practices can affect water quality. A birds-eye view of any community shows the gradation from forested hills, through farmland to suburban, urban, and industrial land use. It is usually crossed by streams and rivers moving excess water to the low areas where it forms the ponds and lakes.

Natural and Disturbed Systems
In a natural setting, water is intercepted by the canopy of trees, and/or shrubs and low plants so that much of the rain never reaches the ground. The water that does reach the soil soaks in slowly, with any excess slowly seeping toward the low areas where it joins pools and streams. As vegetation is removed at harvest, or for streets, parking lots, and buildings, less water is intercepted, more reaches the streams. When cement replaces the forest litter, it prevents water from "soaking" into the ground, where it would seep downward eventually recharging the groundwater. What doesn't soak "in" "runs off" into streams.

Cycle showing how pesticide contaminated material moves from street to stream. The groundwater is the source of water for water supply wells but it also eventually reaches and recharges streams, supplying cool water for fish in the summer months. If the water moves through soil treated with soluble pesticides or fertilizers, both groundwater, then surface water, can become contaminated. It is usually the accumulation of small amouts of pollutants from large areas of land with many uses that creates the problem.

What are pollutants?
A pollutant is a substance in the wrong place.

Manure can help improve soil quality but can be a pollutant (contributing bacteria and nitrogen) if it is washed off site and reaches community waters.
Autumn leaf litter is great for protecting soil and plants, reducing water loss, and enhancing soil tilth by providing food for worms and microorganisms. But when leaves are raked to the street, they are crushed to "ooze" by parking cars and then are carried with storm water to storm drains.
Pesticides designed to solve a pest problem may move with soil or air or on grass clippings that are blown to the street. These contaminants may harm fish and the aquatic insects they rely on for dinner.

Landscape and Gardening Practices Can Contribute to Degraded Community Waters
Too much water on the surface runs off carrying bits of debris and dirt along with any nutrients and pesticides (such as "weed killers") attached to the soil particles down ditches, through storm drains, or directly into local "receiving waters." There they mix with oil, antifreeze, salts, and other contaminants from streets and parking lots. This mix may settle to the bottom or it may stay suspended in the water. Contaminated sediment is costly to remove when the harbors and boat moorages have to be dredged.

Pacific Northwest Regional Water
Quality Coordination Project
Partners
Land Grant Universities
Alaska
Cooperative Extension Service
Contact Fred Sorensen:
907-786-6311
http://www.uaf.edu/ces/water/
University Publications:
http://www.alaska.edu/uaf/ces/publications/
Idaho
University of Idaho
Cooperative Extension System
Contact Bob Mahler: 208-885-7025
http://www.uidaho.edu/wq/wqhome.html
University Publications:
http://info.ag.uidaho.edu/Catalog/catalog.html
Oregon
Oregon State University
Extension Service
Contact Mike Gamroth: 541-737-3316
http://extension.oregonstate.edu/
University Publications:
http://extension.oregonstate.edu/catalog/
Washington
Washington State University
WSU Extension
Contact Bob Simmons:
360-427-9670 ext. 690
http://wawater.wsu.edu/
University Publications:
http://pubs.wsu.edu/
Northwest Indian College
Contact Charlotte Clausing:
360-392-4319
cclausing@nwic.edu or
http://www.nwic.edu/
Water Resource Research Institutes
Water and Environmental Research
Center (Alaska)
http://www.uaf.edu/water/
Idaho Water Resources
Research Institute
http://www.boise.uidaho.edu/
Institute for Water and Watersheds
(Oregon)
http://water.oregonstate.edu/
State of Washington
Water Research Center
http://www.swwrc.wsu.edu/
Environmental Protection Agency
EPA, Region 10
The Pacific Northwest
http://www.epa.gov/r10earth/
Office of Research and Development,
Corvallis Laboratory
http://www.epa.gov/wed/
For more information contact
Jan Seago at 206-553-0038 or
seago.jan@epa.gov

Landscape Features
The physical "improvements" to a landscape also can contribute positively or negatively to the quality of local waters.

Flat terraced hillsides or planted slopes help retain water, while bare slopes speed runoff and may contribute to contamination.

Impervious surfaces (cement walkways, paved parking) increase the amount and speed of water runoff, while porous surfaces such as crushed gravel or porous pavement slow runoff and help hold water on a site.

House roofs shed water creating excesses from the downspouts, but if that water is captured and held at the site with a swale or a garden of water loving plants some may even filter down to recharge groundwater.

Community waters aren't degraded by the one-time pollutant or practice, but rather by multiple pollutants accumulating from the many rural, suburban, and urban landscapes that stretch from hilltop to the shore. Each of us can help improve community waters with small positive actions. In future updates these topics will be considered in greater depth with a focus on ways landscapes can enhance rather than pollute our community waters and sources of more information.

To get started, visit the web sites on community water quality protection below:

Idaho Water Quality Publications and Low Input Landscaping
http://info.ag.uidaho.edu

University of Alaska Extension
http://www.uaf.edu/ces/water/

Oregon State University Well Water Program: list of titles on home gardening and water quality. See also the side bar for other topics.
http://wellwater.oregonstate.edu/lawnsgardens.php

Gardening to Protect Groundwater
http://extension.oregonstate.edu/answer.php#garden

Taking Care of Streams in the PNW: A Homeowner's Guide
http://extension.oregonstate.edu/catalog/pdf/pnw/pnw557.pdf

Washington's Water (WSU)
http://wawater.wsu.edu/

Your Yard and Water Quality: Simple Things Gardeners Can Do To Prevent Water Contamination
http://cru.cahe.wsu.edu/CEPublications/eb1744/eb1744.html

Photo of how over-irrigating can waste water and carry soluble material to water bodies.

National Water Quality Program Areas
The four land grant universities in the Pacific Northwest have aligned our water resource extension and research efforts with eight themes of the USDA's National Institute of Food and Agriculture.

Animal Waste Management
Drinking Water and Human Health
Environmental Restoration
Nutrient and Pesticide Management
Pollution Assessment and Prevention
Watershed Management
Water Conservation and Agricultural Water Management
Water Policy and Economics

NIFA is the Cooperative States Research, Education and Extension Service, a sub-agency of the United States Department of Agriculture, and is the federal partner in this water quality program.

Download the informational PDF flyer here

A cooperative program consisting of the USDA National Institute of Food and Agriculture
and
the Land Grant Colleges and Universities.

- a Regionally-Based National Network -

USDA National Institute of Food and Agriculture

NIFA National Water Quality Program

This material is based upon work supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under Agreement No. 2008-51130-04734.

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page last modified on August 27, 2006