II. Background Information

1. How significant is urban development in the Great Lakes region?
2. What are the impacts of urban development on Great Lakes water quality?
3. How has the Great Lakes policy community responded to this issue?

1. How significant is urban development in the Great Lakes region?

Recent population growth in the Great Lakes region has been accompanied by massive suburban development. Today, more than 33 million people live in the region; four-fifths of them in 17 metropolitan areas (Thorp et al. 1997: 3). While the population has increased quite slowly since World War II, the area occupied by this population has grown much more quickly. In southeast Michigan, a 1.6 percent increase in population increased urbanized land by 28 percent. From 1970 to 1990 the Chicago metropolitan area grew in population by four percent, but spread out across 35 percent more land (www.glc.org/bridges/sprawl/). These trends are expected to continue. By 2020 the population of greater Toronto is expected to grow by two million - and an additional 600 square kilometers will be developed. In Michigan it is predicted that a state population increase of 12 percent by 2020 may be accompanied by an 87 percent increase in developed land (Thorp et al. 1997: 4).

This rapid expansion of developed land, far outstripping population growth, reflects the significance of suburbia as, ever since World War II, the predominant form of urban expansion. Several features are characteristic of this urban form: low-density residential and commercial development, segregated land uses, reliance on the automobile (implying substantial infrastructure and energy requirements), and substantial ecological costs.

Both citizens and policymakers are expressing increasing concerns regarding the environmental implications of suburban development. These implications include loss of agricultural land and natural habitats, deterioration of wildlife populations and of rural human communities, heavy demands on energy and other resources, and air pollution generated by motor vehicles. Of particular relevance, however, is the significance of this form of development as a generator of nonpoint source pollution.

2. What are the impacts of urban development on Great Lakes water quality?

Some of the most pervasive effects of urban development are on water quality and quantity, as a result of replacement of the natural landscape with pavement and other impervious materials. Such surfaces "interrupt the hydrologic cycle, alter stream structure, and degrade the chemical profile of the water that flows through streams. These changes affect fish and wildlife in various ways, and are cumulative within watersheds" (Heinz Center 2002: 266-267). A recent report sponsored by several environmental organizations found that across the United States unchecked suburban development has had a significant impact on water supplies, sending water into streams and rivers as polluted runoff, rather than filtering it through the soil to recharge groundwater aquifers (American Rivers, et al., 2002). Increased urbanization, resulting in a higher proportion of the basin land surface being impermeable to rainfall and runoff, is one of the most important environmental trends now occurring in the Great Lakes region. As little as 10 percent impervious cover can substantially affect the amount of rainfall that filters into the soil, causing reduced groundwater recharge, increased flooding and bank erosion, and diminished stream stability (GLSAB 2000: 4). In summary, then, urban development substantially modifies the hydrological cycle (Figure 1); the environmental implications of this modification are diverse and pervasive.

Figure 1: The Hydrologic Cycle (Source: Environment Canada, The Hydrologic Cycle)

Urban development affects water quality in a variety of ways. Although phosphorus levels have generally decreased to target levels set by the Great Lakes Water Quality Agreement, the nutrient problem is far from resolved. Nitrogen levels in the water column have remained unchanged and soil phosphorus levels continue to increase (GLSAB 2000: 5). In 1995, the Ontario Ministry of the Environment found that the algae Cladophora exhibited continued growth in 16 areas of Lake Erie, and shoreline fouling was observed at four points between Fort Erie and Port Dover (Edsall and Charlton 1997: 59). While sources such as agricultural fertilizers and household detergents have been brought under control, excessive nutrient loads continue to make their way into the Great Lakes. Three urban nonpoint sources appear most significant: atmospheric deposition and subsequent runoff from impervious surfaces, septic system effluent, and lawn fertilization. Of these, atmospheric deposition and runoff is most significant, responsible for 70 to 95 percent of nitrogen, and 20 to 35 percent of phosphorus in urban runoff (Schueler and Caraco 2000: 12).

Urban areas are also partly responsible for elevated contaminant levels in streams and lakes. Roads, parking lots and other impervious surfaces can trap and store volatile organic compounds (VOC's) in porous concrete and asphalt. These are then collected in storm water and rinsed into nearby streams and lakes (Lopes et al. 2000). Other contaminants commonly in urban runoff include zinc, cadmium, copper and PAHs. The Nationwide Urban Runoff Program of the early 1980s found that in many instances concentrations of heavy metals in urban runoff exceed EPA ambient water quality criteria and drinking water standards (Tsanis et al. 1994). Other urban sources of toxic substances include atmospheric deposition and lawn pesticides (IJC 2000: 30). Winter road salt can increase both sodium and chloride levels in water, generating human health concerns (Howard et al. 1993).

Over the last decade pathogenic microorganisms have re-emerged as a significant water quality concern. Since 1990 there have been three major outbreaks of illness as a result of contaminated drinking water. Over 4,000 Milwaukee residents were hospitalized after infection with the parasite Cryptosporidium, while a similar outbreak in Kitchener-Waterloo, Ontario resulted in 200 cases (Edsall and Charlton 1997). Most recently, an outbreak of Escherichia coli in Walkerton, Ontario, claimed seven lives and made over 2,300 ill (O'Connor 2002). The causes of these disease outbreaks are not yet entirely understood, although agricultural sources were likely most significant. But these outbreaks also drew attention to the fact that even after decades of investment, urban sewage systems continue to contribute to hazardous levels of bacteria in the Great Lakes. Many cities continue to use Combined Sewer Overflows, which carry both storm water and household wastewater. At times of heavy rain these systems allow wastewater (including sewage) to overflow into waterways (Lampe et al. 1996). Urban runoff contributes to this problem. City storm systems are designed to remove water quickly from built-up areas. But the network of impervious surfaces used to divert storm water into waterways also collects dirt, trash, sediment and animal feces, degrading water quality (GLSAB 2000). Non-human sources may play a large role in elevated bacterial levels in the Great Lakes. Animal feces, especially of cats and dogs, but also of urban wild animals such as raccoons, can have a major impact on water quality. Studies suggest that as much as 95 percent of coliform in the Great Lakes is from non-human sources.

Finally, increased sedimentation originates, in part, from urban areas. Urban development, and accompanying transportation and storm water infrastructure, tends to transform the hydrological cycle, increasing water runoff into streams and decreasing infiltration into soil. At times of peak flow, this can lead to formation of temporary channels that erode stream banks, depositing sediment downstream or in the lakes themselves. Sediment from construction sites is particularly significant: suspended solids concentrations are often higher near construction sites than anywhere else. The impacts on streams from construction can be severe: "trees and topsoil are removed, soils are exposed to erosion, steep slopes are cut, natural topography and drainage are altered, and sensitive areas are often disturbed" (Schueler and Caraco 2000: 20).

3. How has the Great Lakes policy community responded to this issue?

The foundation for a binational approach to nonpoint source pollutants is the Great Lakes Water Quality Agreement. The GLWQA led to creation of the IJC Water Quality Board and the Science Advisory Board, and, ultimately, to the Pollution from Land Use Activities Reference Group (PLUARG). PLUARG was the first binational panel to explicitly acknowledge the link between urbanization and water quality problems.

Since the 1970s the legal basis for binational cooperation has continued to evolve. Nonpoint source pollution from urban areas is addressed through two annexes of the GLQWA. Annex 3 relates to the control of phosphorus, and includes among its provisions the requirement to undertake nonpoint source programs and measures, including urban drainage management control programs, extending to either level 1 (e.g. erosion controls, use of natural storage capacities and street cleaning), or level 2 measures (e.g. artificial detention and sedimentation of stormwater and runoff and reduction of phosphorus in combined sewer overflows). Annex 13-Pollution from Nonpoint Sources-specifies that Parties are required to identify land-based activities contributing to water quality problems in Remedial Action Plans and Lakewide Management Plans, and to develop and implement watershed plans. Significant progress was made in addressing nonpoint sources in the 1980s (especially from agricultural activities, through such innovations as conservation tillage), but progress has since slowed (GLSAB 2000: 3). According to Kellogg (1997), integration of land use concerns within Remedial Action Plans has been inconsistent.

More generally, there is growing interest in alternatives to low-density suburban development. Much of this interest has focused on "smart growth," defined as an approach to city planning that "aims to continue to provide the jobs, tax revenues and amenities that growth and development provide without degrading the environment, raising local taxes, increasing traffic congestion or breaking local government budgets. Smart growth strives to restore community and vitality to center cities and older suburbs and encourages more town-centered and pedestrian-oriented new development and transit." Ten principles of smart growth have been widely endorsed:

1. Mix land uses.
2. Take advantage of compact building design.
3. Create a range of housing opportunities and choices.
4. Foster walkable, close-knit neighborhoods.
5. Promote distinctive, attractive communities with a strong sense of place.
6. Preserve open space, farmland, natural beauty, and critical environmental areas.
7. Strengthen and direct development toward existing communities.
8. Provide a variety of transportation choices.
9. Make development decisions predictable, fair, and cost-effective.
10. Encourage citizen and stakeholder participation in development decisions.
    (see: www.smartgrowthamerica.org)

A variety of smart growth initiatives are underway across the Great Lakes region, predominately at the state/provincial level (see: (www.glc.org/bridges/smartgrowth/).

Two important political dimensions of suburban development must be emphasized. First, the primary location of policy action on urban nonpoint source pollution, and urban development generally, is not at the federal or state/provincial level, but at the local level: in municipal and regional governments. This implies a highly fragmented responsibility for urban water quality. It also implies that those agencies with the most scientific expertise, such as the Environmental Protection Agency and Environment Canada, have no direct jurisdiction over the issue. Second, powerful forces continue to resist changes in suburban development patterns: many municipalities encourage growth as a means of increasing tax revenues, landowners often oppose efforts to control or redirect development, and continuing consumer demand for single-family housing encourages further suburban expansion.

© Copyright 2002 International Association for Great Lakes Research
Site Design by Loracs Creations, Inc.