(because groundwater recharge is lessened) and flooding since the amount of
water that remains on the surface is greater. Paved surfaces also tend to:
■ Fragment habitats
■ Increase groundwater depletion as water does not infiltrate into the soil to
recharge aquifers
■ Reduce biodiversity and seriously impact food webs in the area since
there is less vegetation available for primary consumers
■ Create microclimates due to the high heat capacity of asphalt, which
causes heat to be more easily captured and stored longer than it would in
the normal landscape
Most municipal storm sewer systems discharge untreated storm water to
streams, rivers, and bays. Urban runoff results in:
■ Runoff containing gasoline, motor oil, heavy metals, trash, fertilizers, and
pesticides
■ Increased erosion and resulting sedimentation in the runoff with the
sediments settling to the bottom of the water bodies and reservoirs,
directly affecting the water quality and the storage capacity
■ An increase in the risk of infections and diseases through contaminated
water supplies
■ An increase in algae growth due to the increased nutrients in the runoff
■ The increased temperature of the water in streams and waterways—this
significantly impacts fish and wildlife as heat is transferred from urban
sources (asphalt, buildings, etc.)
Remediation steps include:
■ Building constructed wetlands to naturally filter water before it’s released
into lakes, rivers, and oceans
■ Building water retention-infiltration basins—shallow artificial ponds that
are designed to infiltrate storm water through permeable soils into the
groundwater aquifer
■ Planning and constructing more open green spaces and parks within urban
communities to increase natural infiltration
■ Frequently using street sweeping vacuums that can reduce the trash and
other debris and pollutants that end up in runoff