Best Management Practices or BMPs are effective, practical, structural or nonstructural methods which prevent or reduce the movement of sediment, nutrients, pesticides and other pollutants from the land to surface or ground water, or which otherwise protect water quality from potential adverse effects of various land-use activities.

Climate Change is defined as a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years.

Combined Sewer is a type of sewer system that collects wastewater and stormwater in a single pipe.  These systems often get overwhelmed during precipitation events.

Combined Sewer Overflows (CSOs) occur when a combined sewer system exceeds capacity and overflows into waterways.  These overflows contain not only stormwater but also untreated human and industrial waste, toxic materials, and debris. They are a major water pollution concern for the approximately 772 cities in the U.S. that have combined sewer systems.  Read more here.

Concentrated Animal Feeding Operations (CAFOs) are agricultural operations where animals are kept and raised in confined situations.

Dry Wells are a type of infiltration device, located underground that collect and infiltrates roof runoff at gutter downspouts, roof valleys, and other places where large amounts of concentrated water flow off of a roof.

Electronic Waste (E-Waste) refers to discarded electronic devices.  In addition to lead, electronics can contain chromium, cadmium, mercury, beryllium, nickel, zinc and flame retardants. When electronics are not disposed of or recycled properly, these materials can cause environmental problems, including water pollution.

Environmental Site Design (ESD), also referred to as Better Site Design (BSD), is an effort to mimic natural systems along the whole stormwater flow path through combined application of a series of design principles throughout the development site to replicate the natural landscape prior to development.

Evapotranspiration is the combination of water that leaves the soil through evaporation and transporation from plants.

Green Infrastructure consists of site-specific management practices that are designed to maintain natural hydrologic functions by absorbing and infiltrating precipitation where it falls or utilizing natural systems that capture, cleanse and reduce stormwater runoff.

Groundwater is water that is underground, stored in rock and soil.

Household Hazardous Waste is leftover household products that contain corrosive, toxic, ignitable, or reactive ingredients are considered to be household hazardous waste (HHW).

Impervious Surfaces are surfaces that do not allow water to infiltrate.  Some examples of impervious surfaces are rooftops and paved roads.

Infiltration devices drain or infiltrate water directly into the ground, providing opportunity for groundwater recharge. Infiltration facilities are below ground, and water should not appear on the surface after 24-48 hours following rainfall. Infiltration trenches and dry wells are example of infiltration devices.

Lake is an inland body of standing water.

Low-Impact Development (LID) is a stormwater management approach that seeks to manage runoff by mimicking a site's predevelopment hydrology by using design techniques that infiltrate, filter, store, evaporate, and detain runoff close to its source. LID preserves natural drainage features and patterns. For more information visit Low Impact Development Center

Non-Point Source Pollution
Non-point Source Pollution

Non-Point Source Pollution is pollution that collects in small amounts from a variety of places.  Cumulatively, these small amounts often result in large amounts of pollution.  Stormwater picks up non-point source pollution as it moves across the land.  Examples of non-point source pollution are oil from cars, trash, and pesticides/fertilizers. 

Pervious Surfaces allow water to infiltrate.  Some examples of pervious surfaces are un-compacted landscaping beds and pervious pavement. 

Point Source Pollution is pollution that is discharged from a single point, such as an oil spill.

Rain Barrel is a device to collect rainwater from downspouts. Rain barrels can be bought in a store or made at home.

Rain Garden is a landscaping feature that is planted with wild flowers and other native plants that stores and infiltrates water runoff from a roof, driveway, or other paved surface. The water slowly seeps into the ground instead of heading for the nearest storm drain.

River is a large natural stream of water emptying into an ocean, lake, or other body of water and usually fed along its course by converging tributaries.

The Point
The Monongahela, Ohio, and Allegheny Rivers converging at Pittsburgh's "Point"

Runoff is water or snow melt that is not absorbed by soil during a precipitation event and flows into surface waters.

Sanitary Sewer is a type of sewer system that is designed to collect only wastewater.  Where these sewer systems are present, stormwater is conveyed to local waterways in pipes designed exclusively for stormwater. 

Separate Sewer Overflows (SSOs) occur when sanitary sewers exceed capacity and overflow.  EPA estimates that there are at least 23,000 - 75,000 SSOs per year (not including sewage backups into buildings). The untreated sewage from these overflows can contaminate our waters, causing serious water quality problems. It can also back-up into basements, causing property damage and threatening public health.  Read more at the EPA website.

Surface Water is a natural body of water that has not penetrated much below the surface of the ground.

Stormwater is water that originates during precipitation events.

Stormwater Runoff is generated when precipitation from rain and snowmelt events flows over land or impervious surfaces and does not percolate into the ground.

Urban Forestry is the management of trees and plants or forested area located within a city or other urban area.

Watershed is an area of land that drains precipitation (rain and snow) into a stream, river, wetland, lake or ocean.

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 Educational Materials

The Point, Larger Version
Green Roof, Larger Version
Lake Arthur, Larger Version

Who We Are

Erin Kepple Adams
Claire Jordy

Pennsylvania Stormwater Regulations

State & Federal Water Laws
Federal Laws | Pennsylvania Code

Regulatory Agencies & Legislative Resources



Watershed Information and Regional Watershed Conservation Plans

GIS Data Sources

Green Infrastructure


Regional Stakeholders

Key Contacts


Grants & Funding Resources

Land Use/Land Cover
Allegheny | Armstrong | Beaver |
Bulter | Fayette | Greene | Indiana |
Lawrence | Washington |


Water Resource Maps
MS4 Communities in the SPC Region
Act 167 Watersheds

NFIP Communities in the SPC Region Impaired Waterways by Source
Designated Uses in SPC Region
Total Maximum Daily Loads (TMDLs) for Impaired Waterways
Population Density
Bedrock Formations


Municipal Separate Stormwater System (MS4)

SPC Educational Resources

SPC Workshop Materials


Stormwater Management & Best Management Practices

Free Educational Webinars and Online Training

Resources for Student Education


SWPA's Homeowner's Guide To Stormwater

Climate Change and Water Resources

Resources for Water Suppliers & Wastewater Managers

Additional Water
Quality Information

UPDATED! Quick Resource Guide to the MS4 Program

Quick Resource Guide for Winter Maintenance BMPs

Education Materials SPC Water Resource Center