when it rains, it drains

When It Rains,It Drains

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Quality vs. Quantity

• How has stormwater runoff changed in quality over the past 100 years?

• How has stormwater runoff changed in quantity over the past 100 years?

• https://www.youtube.com/watch?v=0x-TDvnbheM

Stormwater Runoff

• Water falls as rain, snow, or ice

• Most water seeps into the ground

• If the ground is saturated, frozen, or has an impermeable surface, water flows as runoff

Point vs. Non-Point Source

Point vs. Non-Point Source

• Point source:– Travels through a conveyance system– Regulated under permit program

• Non-point source:– Runoff that comes from a wide unspecific area– Addressed through voluntary programs

Why is stormwater a problem?

• Human activities cause stormwater to decrease in quality and increase in quantity

• Caused by developed and disturbed land

Where does stormwater go?

• Travels over land• Carried through Municipal Separate Storm

Sewer Systems (MS4)• Discharges into various creeks and streams• Ultimately, the creeks and streams discharge

into a larger body of water, like the Schuylkill River

Where does stormwater go?

• Stormwater flows to storm drains along the street

• Water may carry pollutants with it

• This runoff goes to streams, rivers, lakes, and the oceans untreated

Sediment Pollution

• Sediment comes from soil erosion and from decomposition of plants and animals

• Sediment makes water cloudy

• Sediment is the most common type of water pollutant

Sediment Pollution Prevention

• Create vegetative buffers along bodies of water

• Minimize the amount of exposed soil

• Use silt fences when disturbing soil

Oil and Grease Pollution

• The EPA estimates that 200 million gallons of oil are improperly disposed of each year

• 1 quart of oil can contaminate 1 million gallons of water

Oil and Grease Pollution Prevention

• Fix vehicles that are leaking fluid

• If you change your own oil, store it in a container and dispose of properly

Septic System Pollution

• The EPA estimates that 25% of homes in the U.S. use septic systems

• Over 4 billions gallons of wastewater per day is dispersed below ground through septic systems

• http://www.youtube.com/watch?v=gRz0wrwK8vs

Septic System Pollution Prevention

• Have septic system pumped regularly• Fix a faulty septic system• Fix faulty toilets and leaky faucets to reduce

water going through the system• Don’t overload the septic system (ex: you

should do several loads of laundry over several days, rather than all in one day)

Lawn Chemical Pollution

• Lawn chemicals are fertilizers, herbicides, and insecticides

• Over-application can result in toxic levels of chemicals and excessive nutrient runoff

Lawn Chemical Pollution Prevention

• Conduct a soil test• Don’t over-fertilize• Use chemicals

according to their instructions

• Landscape with native plants

Thermal Pollution

• Rain or snowmelt running over pavement picks up heat from asphalt and concrete

• Warm runoff raises the temperature of bodies of water

Thermal Pollution Prevention

• Install permeable pavement to allow water to infiltrate into the soil

• Plant vegetation in riparian zones to increase shade

Non-Structural BMPs

• Pollution prevention and source control• Street sweeping• Stormwater collection system cleaning and

maintenance• Low-impact development and land-use

planning• Public education

Structural BMPs

• Green roofs• High density

residential areas• Grassed/porous

pavement• Silt fences

Rain Gardens

Rain Gardens

Rain Impoundment Basin

Benefits of Stormwater Management• Enhances opportunities

for recreation• Reduces flood damage• Improves drinking

water quality• Benefits aquatic

organisms• Reduces illness• Enhances aesthetic

value