APES Unit 5.13 Methods to Reduce Urban Runoff

Practice FRQ

★ Design an investigation to measure the relationship between the number of trees in a city and amount of stormwater runoff the

city produces

a) Propose a hypothesis for your investigation.

b) Outline a procedure for your investigation.

c) Identify your independent variable.

d) Identify your dependent variable

a) I hypothesize that the number of trees in a city is inversely proportional to the number of stormwater runoff the city produces.

b) I would compare the outcomes of three different scenarios: one city area with no trees, one with a minimal number of trees, and one with an abundance of trees.

c) The independent variable is the number of trees.

d) The dependent variable is the amount of stormwater runoff produced by the city.

Urban Runoff

Water in urban area that doesn’t evapotranspire or infiltrate soil (instead, drainage systems like sewers and urban streams

• Reducing Runoff → Reduces pollutants and volume of water

Salt

Pollutant: Plant and insect death

Sediment

Pollutant: Turbidity

Fertiier

Pollutant: Eutrophication

Pesticides

Pollutant: Kills non-target species

Oil and Gasoline

Pollutant: Suffocates aquatic organisms

Permeable Pavement

Designed to allow stormwater to infiltrate and recharge ground water

• Decreases Runoff: Thus pollutants in local water/storm drains

• Decreases Flooding: From rainfall

Urban System to Collect Water

Rain Garden: Habitats for pollinators + sense of place + carbon reservoir

Build Up, Not Out

Taller buildings so “footprint” on city surface remains while capacity of living/office space increases

• Decreases Impervious Surfaces

Increasing Planting of Trees and Public Transit

More cars on the road →street pollution + runoff into drains and local waters

• Public Transit: Also reduces traffic

• Trees: CO2