What is stormwater?

Stormwater is probably a term you have heard before, but what does it mean? When it rains or when the snow is melting in the spring, that water runs across the ground. Where that water runs is significant. If it runs over impervious surfaces, it has the potential to pick up dirt and pollutants. When the stormwater runs across a paved parking lot, it can pick up litter and debris and carry it along until it finds a stream to flow into. The stormwater may run across your roof, draining through the gutters, flowing onto your grass, and then finding its way into the roadside ditch or stormdrain. Are there chemicals on your lawn for it to pick up along the way? Maybe even dog poop? 

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Water is constantly moving and flowing into a larger body of water, which we call a watershed. That includes all of our creeks, streams, ditches, rivers, and groundwater. We all live in a watershed. Our job is to make sure that stormwater is not picking up contaminants on it's way to our lakes and rivers. Ask yourself: what kind of impact am I having on our waterways? Maybe you feel like you're just one person, but each and every person together makes a huge impact everyday. Make sure the water that flows from your home, school, or place of work isn't flowing downhill with dirt, debris, or chemicals. The health of our drinking water is in all of our hands. We all make an impact; make sure it's a positive one!

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New York State Department of Environmental Conservation defines stormwater as:

"Stormwater is water from rain or melting snow that doesn't soak into the ground but runs off into waterways. It flows from rooftops, over paved areas and bare soil, and through sloped lawns while picking up a variety of materials on its way. The quality of runoff is affected by a variety of factors and depends on the season, local meteorology, geography and upon activities which lie in the path of the flow."

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What is an impervious surface?
Impervious surfaces include streets, parking lots, driveways, sidewalks, and buildings. These impenetrable surfaces prevent runoff waters from naturally infiltrating into the groundwater system. 

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Think about how the world has changed in the last 50 years? 10 years? Few months? Development is constantly increasing. This is great for our homes, schools, population, etc. When a new building is constructed or a new housing development is built, what happens? A new road or parking lot is paved, more rooftops appear, more sidewalks are constructed, etc. These are all impervious surfaces. Rain water used to absorb into the ground like a sponge at these locations when they were a farm field or woodlot. Now, that water is going to need to go somewhere, but where? That is where stormwater best management practices (BMPs) and green infrastructure practices come into play. 

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What is MS4?

The term MS4 does not solely refer to municipally-owned storm sewer systems, but rather is a term with a much broader application that includes, in addition to local jurisdictions: State departments of transportation, public universities, local sewer districts, public hospitals, military bases and prisons. An MS4 is not always just a system of underground pipes; it can include roads with drainage systems, gutters, and ditches.

 

The regulatory definition of an MS4 is:
According to 40 CFR 122.26(b)(8), “municipal separate storm sewer means a conveyance or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains): 

 

1. Owned or operated by a State, city, town, borough, county, parish, district, association, or other public body (created by or pursuant to State law)…including special districts under State law such as a sewer district, flood control district or drainage district, or similar entity, or an Indian tribe or an authorized Indian tribal organization, or a designated and approved management agency under section 208 of the Clean Water Act that discharges into the waters of the United States.” (Note: “Waters of the United States” refers to surface water only.) 

2. “Designed or used for collecting or conveying storm water 

3. Which is not a combined sewer; and  

4. Which is not part of a Publicly Owned Treatment Works (POTW) as defined at40 CFR 122.2"

According to 40 CFR 122.26(b)(16)iii, small MS4s (population less than 100,000) “includes systems similar to separate storm sewer systems in municipalities, such as systems at military bases, large hospitals or prison complexes, and highways and other thoroughfares. The term does not include separate storm sewers in very discrete areas such as individual buildings.”

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For more information go to:

• NYS Department of Environmental Conservation Website

• Environmental Protection Agency Website

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What is a SWMP?

The purpose of the Stormwater Management Plan (SWMP) is to implement programs and practices to control polluted storm water runoff.