CAUTION Macon  

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Macon, Ga

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    Grassy Swales  

   

Grassy Swales
Picture of a parking lot where a series of vegetated swales capture stormwater runoff from the parking lot. These densely vegetated swales incorporate a variety of trees, grasses, and shrubs. Small check dams slow and spread the flow. Cuts in the curbs allow stormwater to enter the swales.  - http://www.lcrep.org/fieldguide/examples/swale.htm
Swales in Parking Lots
What is a grassy drainage swale?

Swales are grassy depressions in the ground designed to collect stormwater runoff from streets, driveways, rooftops and parking lots. The grass in the swale removes pollutants from stormwater as the water infiltrates into the soil. The treated water recharges groundwater supplies including the Spokane Valley - Rathdrum Prairie Aquifer. The Aquifer is the sole source of drinking water for the greater Spokane and Coeur d’Alene metropolitan areas.

http://www.spokanecounty.org/utilities/stormwtr/data/sw-2.pdf

Developers Must Curb Runoff, Board Says Pollution:
Water panel imposes strict guidelines on new buildings, malls, gas stations and homes.
In a sweeping effort to prevent Los Angeles County beaches from becoming more polluted as population grows, the region's water quality board Wednesday approved standards to require new building projects across the county to limit urban runoff that fouls ocean waters.. . .
Each project must collect or filter runoff from the first three-quarters of an inch of rain that falls in a 24 hour period. Developers will have a range of options to comply. One option is to plant grassy swales so runoff can seep into the ground instead of flowing into storm drains.
http://www.drainpac.com/LATimestext.htm


This shows picture of combination of "perforated" CURBS and SWALES and sidewalks-
Swales and Curbs
A number of new streets in the Rivergate area of North Portland utilize perforated curbs and grassy swales to infiltrate stormwater generated by the streets and sidewalks. The system looks and performs exactly like a traditional curb and gutter system except for the small rectangular holes in the curbs that allow water to drain from the street into the grassy swales – thereby keeping stormwater out of the storm system. An overflow outlet connects to a traditional storm drain in case a large storm overflows the swales.
Swales with Curbing
http://www.lcrep.org/fieldguide/examples/curbalternatives.htm


Water quality of highway runoff in the Austin, Texas area was determined by monitoring runoff at three locations . . .

The effectiveness of grassy swales for treating highway runoff was evaluated by comparing the runoff at one of the sites, before and after passing across a swale. The grassy swale proved effective for reducing the concentrations of most constituents in runoff. The low runoff coefficient due to infiltration of runoff into the swale produced a large reduction (90%) in pollutant load discharged. This reduction of runoff volume effectively reduces the impact of constituents whose concentrations are not reduced by the swale.
http://www.crwr.utexas.edu/reports/1995/rpt95-10.shtml


   

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Forest Hill Road