Infrastructure planning involves changes in the regional growth planning process to contain 'sprawl' development. Sprawl development is the expansion of low-density development into previously undeveloped land. The American Farmland Trust has estimated that the United States is losing about 50 acres an hour to suburban and exurban development (Longman, 1998). This sprawl development requires local governments to extend public services to new residential communities whose tax payments often do not cover the cost of providing those services. For example, in Prince William County, Virginia, officials have estimated that the costs of providing services to new residential homes exceeds what is brought in from taxes and other fees by $1,600 per home (Shear and Casey, 1996).
Infrastructure planning makes wise decisions to locate public services, water, sewer, roads, schools, and emergency services in the suburban fringe and direct new growth into previously developed areas, discouraging
low-density development. Generally, this is done by drawing a boundary or envelope around a community, beyond which major public infrastructure investments are discouraged or not subsidized. Meanwhile, economic and other incentives are provided within the boundary to encourage growth in existing neighborhoods. By encouraging housing growth in areas that are already provided with public services, water, sewer, roads, schools, and emergency services communities not only save infrastructure development costs, but reduce the impacts of sprawl development on urban streams and water quality.
Sprawl development negatively impacts water quality in several ways. One of the most significant impacts comes from the increase in impervious cover that is associated with 'sprawl' growth. In addition to impervious area from rooftops, extension of road systems and additions of paved surface from driveways create an overall increase in imperviousness. This increase in the impervious cover level of an area directly influences local streams and water quality by increasing the volume of stormwater runoff. These elevated runoff levels impact urban streams in several ways, including enlarging stream channels, increasing sediment and pollutant loads, degrading stream habitat, and reducing aquatic diversity (Schueler, 1995). Sprawl has been reported to generate 43 percent more runoff that contains three times greater sediment loads than traditional development (SCCCL, 1995).
Sprawl development influences water quality in other ways. This type of development typically occurs in areas not served by centralized sewer or water services. For example, over 80 percent of the land developed in the state of Maryland in the last decade has been outside the sewer and water "envelope." This requires new housing developments to use septic systems or another form of on-site wastewater disposal to treat household sewage. These on-site treatment systems can represent a significant source of nutrients and bacteria that affect both surface waters and groundwater. More information about septic systems is contained in the fact sheets in both the Illicit Discharge Detection and Elimination Minimum Measure and the Pollution Prevention Minimum Measure.
Sprawl development occurs in all regions of the country and has recently become the subject of many new programs to counteract its impacts. These programs seldom focus on the water quality implications of sprawl growth, instead concentrating on economic and transportation issues. Even so, methods such as infrastructure planning can reduce the impact of new development. Promoting the infill and redevelopment of existing urban areas in combination with other better site design techniques (see the other fact sheets in this minimum measure) will decrease impervious cover levels and lessen the amount of pollution discharged to urban streams.
Siting and Design Conditions
Various techniques have been used to manage urban growth while conserving resources. Although none of these techniques specifically concentrates on infrastructure planning, each of the techniques recognizes that directing growth to areas that have been previously developed or promoting higher density development in areas where services exist prevents sprawl development and helps communities to mitigate the water quality impacts of economic growth. Among the techniques that have been used are:
Urban Growth Boundaries. This planning tool establishes a dividing line that defines where a growth limit is to occur and where agricultural or rural land is to be preserved. Often, an urban services area is included in this boundary that creates a zone where public services will not be extended.
Infill/Community Redevelopment. This practice encourages new development in unused or underutilized land in existing urban areas. Communities may offer tax breaks or other economic incentives to developers to promote the redevelopment of properties that are vacant or damaged.
Intense development of existing areas can create a new set of challenges for stormwater program managers. Stormwater management solutions can be more difficult and complex in ultra-urban areas than in suburban areas. The lack of space for structural stormwater controls and the high cost of available land where structural controls could be installed are just two problems that program managers will face in managing stormwater in intensely developed areas.
Infrastructure planning is often done on a regional scale and requires a cooperative effort between all the communities within a given region in order to be successful. Stormwater managers will need to develop lines of communication with other state and local agencies and community leaders to ensure that infrastructure plans direct growth to those areas that will have the least impacts on watersheds and water quality.
The effectiveness of infrastructure planning at protecting water quality is currently unknown. Although studies exist detailing the economic benefits of infrastructure planning, how this translates to stormwater pollutant reductions is difficult to calculate. However, a relationship exists between impervious cover levels and urban stream characteristics, and one can assume that tools such as infrastructure planning that help control imperviousness have a positive impact on water quality.
Compact development benefits program managers in numerous ways. One benefit is that compact development can preserve prime agricultural land and sensitive areas while reducing costly construction of new infrastructure (Pelley, 1997). Less new land developed translates into less need for new infrastructure and public services.
The economic benefits of reducing costly construction of new infrastructure and providing new services can be quite substantial. The following is a list of examples of the projected savings of limiting sprawl through managed growth (APA, no date):
- New Jersey's plan for managed growth will save the state $700 million in road costs, $562 million in sewer and water costs, $178 million in school costs, and up to $380 million in operating costs per year.
- Fifteen years of continued sprawl would cost Maryland $10 billion more than a more compact pattern of growth.
- A 1989 Florida study demonstrated that planned, concentrated growth would cost the taxpayer 50 percent to 75 percent less than continued sprawl.
- The Cities of Minneapolis-St. Paul will spend $3.1 billion by the year 2020 for new water and sewer services to accommodate sprawl.
- Since 1980 the City of Fresno, California, has added $56 million in yearly revenues but has added $123 million in service costs.
Other studies have found that planned development consumes about 45 percent less land and costs 25 percent less for roads, 15 percent less for utilities, 5 percent less for housing, and 2 percent less for other fiscal impacts (Burchell and Listokin, 1995, as cited in Pelley, 1997).
The control of sprawl development through legislation and "Smart Growth" programs is currently being implemented in a number of states and counties across the U.S. As these programs mature and begin to influence development patterns in urban areas, local governments should begin to see the positive impacts of condensed growth on the aquatic environment and water quality of local streams.
American Planning Association (APA). No date. Points of View: Paying for Sprawl. Accessed November 17, 2005.
Burchell, R.W., and Listokin. 1995. Land, Infrastructure, Housing Costs and Fiscal Impacts Associated with Growth: The Literature on the Impacts of Sprawl Versus Managed Growth. Lincoln Institute of Land Policy, Cambridge, MA.
Longman, P. 1998. Who Pays for Sprawl? U.S. News and World Report.
Maryland Office of Planning (MOP). No date. Priority Funding Areas. [www.mdp.state.md.us/fundingact.htm
]. Accessed November 17, 2005.
Pelley, J. 1997. The Economics of Urban Sprawl. Watershed Protection Techniques 2(4):461¿467.
Schueler, T.R. 1995. Site Planning for Urban Stream Protection. Metropolitan Washington Council of Governments, Washington, DC.
Shear, M.D., and W. Casey. 1996, June 21. Just Saying "Yes" to Developers. The Washington Post, p. A1.
South Carolina Coastal Conservation League (SCCCL). 1995. Land Development Bulletin. Fall 1995. South Carolina Coastal Conservation League, Charleston, SC.
Center for Watershed Protection (CWP). 1998. Better Site Design: A Handbook for Changing Development Rules in Your Community. Center for Watershed Protection, Ellicott City, MD.
Harbinger Institute. 1998. Smart Talk for Growing Communities: Meeting the Challenges of Growth and Development. Prepared for the Congressional Exchange, Washington, DC, by the Harbinger Institute, Kapa'au, HI.
International City/County Management Association (ICMA). 1998. Why Smart Growth: A Primer. International City/County Management Association, Washington, DC.
Redman Johnston Associates, Ltd. 1997. Beyond Sprawl: Land Management Techniques to Protect the Chesapeake Bay. EPA 903-B-97-005. Prepared for the U.S. Environmental Protection Agency, Chesapeake Bay Program, by Redman Johnston Associates, Ltd., Easton, MD.