The Environmental Impact of Urban Sprawl

Urban sprawl is detrimental to the environment. Our country is facing an environmental crisis, losing green space, farmland, and important ecosystems, all at the hand of urban sprawl. As urban areas grow, the environmental problems grow exponentially. Here are some of the environmental problems caused by urban sprawl.

Decrease in Water Quality
Paved surfaces create runoff during rainstorms. This runoff picks up oil, chemicals, and gravel from the pavement and grass. These chemicals would usually be filtered out of the water through the ground, however, due to the increase in concrete, now run off into streams. Fertilizers from yards run off into streams causing algae blooms. The algae blooms decrease the oxygen in the water, killing the fish. The water supply for the towns becomes contaminated.

Decrease in Air Quality
Urban sprawl causes a significant decrease in air quality. People spend much more time in cars commuting to work and running errands. Commuting to work use to take people 10-15 minutes in the car. Today, people are spending 30 minutes or more commuting to work due to urban sprawl. The extra exhaust decreases the air quality.

Less Groundwater
More paved surface means that there is less infiltration for groundwater. Areas that depend on groundwater as a source of public water supply are facing a water crisis as the aquifer becomes depleted. In addition, these areas are facing a problem with land subsidence. The increase demand on the groundwater due to urban sprawl has created a void in the aquifer. The land compresses, causing flooding problems, cracking of foundations, etc. San Jose has suffered more than 13 feet of land subsidence due to this problem.

Loss of Farmland
Between 1992 and 1997 13.7 million acres of farmland were converted to housing developments and highways.

Loss of Wetlands
Wetlands surrounding streams help prevent flooding. In addition, wetlands slow down runoff entering a stream. Wetlands absorb chemicals in runoff. Without wetlands to act as buffer, the water supply becomes contaminated and more areas flood.

Loss of Green Space
Urban sprawl takes away green space used for recreation, farmland, and improvement of air quality.

Light Pollution
One of the most overlooked repercussions of urban sprawl is the amount of light pollution. Our children are growing up not knowing the wonders of the nighttime sky.

Loss of Wildlife
Urban sprawl has a profound affect on wildlife and habitat. According to a study done in Wisconsin, only 0.5% of the grasslands remain in Wisconsin. 50% of the wetlands in Wisconsin were lost to urban sprawl. Also only 500 acres of oak savannas exist in Wisconsin. This is down from the 5.5 million acres of oak savannas that originally existed there. This is 0.01% of the original oak savanna habitat. This loss in habitat leaves animals no place to go. Suburbs begin to be overrun with deer, the threat of coyotes, and experience significant increases in road kill.

Heat Island Effect
Many cities and suburbs experience a heat island effect, where the temperature increases in the area due to the increase in the amount of asphalt and buildings. In some areas, this increase in temperature could be as much as 7 degrees F.

It has become evident that the amount of environmental problems caused by urban sprawl is significant. Urban areas cannot continue to grow without sparking an environmental crisis beyond repair. Solutions to these problems must be explored and enacted through careful planning.