Relevant points to consider when working to reduce developmental impacts through

Site Planning and Developmental Design.

The information represents an adaptation of that produced by the Center for Watershed Protection, Better Site Design: A Handbook for Changing Development Rules in Your Community, August 1998 and Consensus Agreement On Model Development Principles To Protect Our Streams, Lakes, and Wetlands, April 1998. Go to: http://www.cwp.org/22_principles.htm


Residential Street and Parking Lots
• Design residential streets for the minimum required pavement width needed to support travel lanes, on-street parking, and emergency service vehicle access. These widths should be based on estimated traffic volume.
• Consider the implementation of a Traditional Neighborhood Design (TND) ordinance that will by design result in more compact community design, less roadway, shared parking and overall less surface acreage impacts.
• In springshed and karst landscapes minimize the use of curbs and gutters roadside and instead, encourage use of grassed roadside swales to maximize both onsite treatment of stormwater runoff and stormwater attenuation to the ground water.
• Reduce the total length of residential streets by examining alternative street layouts to determine the best option for increasing the number of homes per unit length.
• Wherever possible, residential street right-of-way widths should reflect the minimum required to accommodate the travel-way, the sidewalk, and vegetated drainageways. Utilities and storm drains should be located within the pavement section of the right-of-way wherever feasible.
• Minimize the number of residential street cul-de-sacs and incorporate landscape areas to reduce their impervious cover. The radius of cul-de-sacs should be the minimum required to accommodate emergency and maintenance vehicles. Alternative turnarounds should be considered.
• Where density, topography, soils, and slope permit, vegetated open channels should be used in the street right-of-way to convey and treat stormwater runoff.
• Relax required parking space standards and encourage shared parking between adjacent businesses. The required parking ratio governing a particular land use activity should be enforced as both a maximum and a minimum in order to curb excess parking space construction. Existing parking ratios should be reviewed for conformance, taking into account local and national experience to see if lower ratios are warranted and feasible. Often, local development requirements are forcing parking lots at each new business to be designed for peak holiday loads - results in excessive amounts of paved impervious surface.
• Parking codes should be revised to lower parking requirements where transit is available or enforceable shared parking arrangements are made.
• Reduce the overall imperviousness associated with parking lots by providing compact car spaces, minimizing stall dimensions, incorporating efficient parking lanes, and using pervious materials in the spillover parking areas where possible.
• Provide meaningful incentives to encourage structured and shared parking to make it more economically viable. Use local development review process to suggest and initiate shared parking opportunities for adjacent properties.
• Wherever possible, provide stormwater treatment for parking lot runoff using bioretention areas, filter strips, and/or other practices that can be integrated into required landscaping areas and traffic islands.

Lot Development
 • Advocate open space design development incorporating smaller lot sizes to minimize total impervious area, reduce total construction costs, conserve natural areas, provide community recreational space, and promote springshed protection.

Traditional subdivision design results in more road surface necessary, larger lots with less intact natural areas/habitat being preserved. In an open space design, smaller house lots result in more acerage of natural lands/habitat being protected and incorporated into the subdivision as common open space. Also, less road surface and other infrastructure deployment is necessary.


• Relax side yard setbacks and allow narrower frontages to reduce total road length in the community and overall site imperviousness. Relax front setback requirements to minimize driveway lengths and reduce overall lot imperviousness.
• Promote more flexible design standards for residential subdivision sidewalks. Where practical, consider locating sidewalks on only one side of the street and providing common walkways linking pedestrian area.
• Reduce overall lot imperviousness by promoting alternative driveway surfaces and shared driveways that connect two or more homes together.
• Clearly specify how community open space will be managed over the long term and designate a sustainable legal entity responsible for managing both natural and recreational designated open space.
• Direct rooftop runoff to pervious areas such as yards, open channels, or vegetated areas and avoid routing rooftop runoff to the roadway and the stormwater conveyance system.

Conservation of Natural Areas
 • Create a variable width, naturally vegetated buffer system along all perennial streams that also encompasses critical environmental features such as the 100-year floodplain, sinkholes, karst depressional features, slopes, and wetlands.

Graphic provided by George Vellidis, Associate Professor, University of Georgia, Tifton, GA.

• Preserved riparian stream buffers or sinkhole buffers or restored damaged areas with native vegetation. The buffer system should be identified and established through use of local the development project review process.

• Limit the clearing and grading of forested and native vegetation areas at a site. The minimum amount needed to build lots, allow access, and provide fire protection should be planned and used. A fixed portion of any community open space should be managed as protected green space in a consolidated manner. The best situation is to have these open space areas dedicated and a permanent easement established and recorded
• Conserve trees and other vegetation at each site and plant additional vegetation where impacts have occurred, clustering tree areas, and promoting the use of native plants that do not require excessive fertilization or watering. Wherever practical, manage community open space, street right-of-ways, parking lot islands, and other landscaped areas to minimize hardened surfaces, include shallow grassed swales, well planned multipurpose retention and detention areas with natural biological filtering capacity and vegetated edges.
• Use incentives and flexibility in the form of density compensation, buffer averaging, property tax reduction, stormwater credits, and by-right open space development should be encouraged to promote conservation of stream buffers, forests, meadows, and other areas of environmental value. In addition, off-site mitigation consistent with locally adopted plans should be encouraged.
• Ensure that new or redeveloped stormwater outfalls should not discharge untreated stormwater into sinkholes, jurisdictional wetlands, springshed principal recharge areas, or other identified sensitive areas.