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1. What is stormwater runoff?

Stormwater runoff is precipitation from rain or melting snow that "runs off" across the land instead of seeping into the ground. This runoff usually flows into the nearest: 

• Creek
• Lake
• Ocean
• River
• Stream

Collectively, the draining water is called stormwater runoff and is not treated in any way.

2. What is polluted runoff?

Water from rain and melting snow either seeps into the ground or "runs off" to lower areas, making its way into streams, lakes and other water bodies. Stormwater runoff becomes a problem when it picks up and carry's debris, chemicals, dirt and other pollutants as it flows or when it causes flooding and erosion of stream banks. Some - like pesticides, fertilizers, oil and soap - are harmful in any quantity. Others - like sediment from construction, bare soil, or agricultural land, or pet waste, grass clippings and leaves - can harm creeks, rivers and lakes in sufficient quantities.

In addition to rain and snowmelt, various human activities like watering, car washing, and malfunctioning septic tank can also put water onto the land surface. Here, it can also create runoff that carries pollutants to creeks, rivers and lakes.

How It Happens

Polluted runoff generally happens anywhere people use or alter the land. For example, in developed areas, none of the water that falls on hard surfaces like roofs, driveways, parking lots or roads can seep into the ground. These impervious surfaces create large amounts of runoff that picks up pollutants. The runoff flows from gutters and storm drains to streams. Runoff not only pollutes' but erodes stream banks. The mix of pollution and eroded dirt muddies the water and causes problems downstream.

3. What causes polluted stormwater runoff?

Polluted stormwater runoff generally happens anywhere people use or alter the land. People going about their daily lives are the number one source of stormwater pollutants. Most people are unaware of how they impact water quality. Some common examples include: 

• Excessive Pesticide Use
• Letting Oil Drip out of Their Vehicles
• Littering
• Not Picking up Pet Waste
• Over Fertilizing Lawns
• Using Salt or Fertilizer to De-Ice Driveways

Developed Areas

Developed areas in general, with their increased runoff, concentrated numbers of people and animals, construction and other activities, are a major contributor to Non-point source pollution, as are agricultural activities. Other contributors include forest harvesting activities, roadways, and malfunctioning septic systems.

4. Why do we need to manage stormwater and polluted runoff?

Polluted stormwater runoff is the number one cause of water pollution in Texas. In most cases in Texas today, stormwater either does not receive any treatment before it enters our waterways or is inadequately treated. Polluted water creates numerous costs to the public and to wildlife. As the saying goes, "we all live downstream." Communities, such as Abilene, that use surface water for their drinking supply must pay much more to clean up polluted water than clean water.

Polluted water hurts the wildlife in creeks, streams, rivers and lakes. Dirt from erosion, also called sediment, covers up fish habitats while fertilizers can cause too much algae to grow, which also hurts wildlife by using up the oxygen they need to survive. Soaps hurt fish gills and fish skin, and other chemicals damage plants and animals when they enter the water.

The quantity of stormwater is also a problem. When stormwater falls on hard surfaces like roads, roofs, driveways and parking lots, it cannot seep into the ground, so it runs off to lower areas. To give you an idea of the difference a hard surface makes, consider the difference between one inch of rain falling onto a meadow and a parking lot. The parking lot sheds 16 times the amount of water that a meadow does!

Developed Areas

Because more water runs off hard surfaces, developed areas can experience local flooding. The high volume of water also causes streams banks to erode and washes the wildlife that lives there downstream.

5. What is the City of Abilene doing about stormwater runoff?

The City of Abilene is preventing stormwater pollution through a stormwater management program. This program addresses stormwater pollution from construction, new development, illegal dumping into storm sewer systems and drainage ways, and pollution prevention and good housekeeping practices in municipal operations. It will also continue to educate the community and get everyone involved in making sure that only thing that stormwater contributes to our water resources is: water.

6. How is stormwater runoff “managed”?

"Best Management Practices (BMP)" is a term used to describe different ways to keep pollutants out of runoff and to slow down high volumes of runoff. Preventing pollution from entering water is much more affordable than cleaning polluted water! Educating City residents about how to prevent pollution from entering waterways is one best management practice. Laws that require people and businesses involved in earth disturbing activities -like construction and agriculture - to take steps to prevent erosion are another way to prevent stormwater pollution. There are also laws about litter, cleaning up after pets and dumping oil or other substances into storm drains.

Education and laws are just two best management practice examples. Some BMPs are constructed to protect a certain area. Some are designed to slow down stormwater, others help reduce the pollutants already in it - there are also BMPs that do both of these things.

Examples

Detention ponds, built to temporarily hold water so it seeps away slowly, fill up quickly after a rainstorm and allow solids like sediment and litter to settle at the pond bottom. Then, they release the water slowly. These ponds are one constructed BMP example. Other examples include:

• Filter Strips
• Green Roofs
• Permeable Paving
• Sediment Fences
• Storm Drain Grates

7. If it only affects streams and creeks, why should I care?

Streams and creeks feed into rivers, lakes and eventually the ocean. We all drink water, so we are all affected when our water is polluted. When water treatment costs rise, the price of drinking water goes up. If you like to fish, swim or boat, you may have heard or been affected by advisories warning you not to swim, fish or boat in a certain area because of unhealthy water or too much algae. Shellfish like clams, oysters, and shrimp cannot be harvested from polluted waters, so anyone that enjoys these foods or makes a living from the shellfish industry is affected. 

Money made from tourism and water recreation can also be impacted, as are businesses and home flooded by stormwater runoff. When we pollute our water, everyone is affected!

8. Why all the recent fuss about stormwater?

The Federal Clean Water Act requires large and medium sized towns (Abilene meets the large criteria) across the United States to take steps to reduce polluted stormwater runoff. The law was applied in two phases. The first phase addressed large cities. The second phase, often referred to as "Phase II," requires medium and small cities, fast growing cities and those located near sensitive waters to take steps to reduce stormwater.

These laws require chosen cities to create a Stormwater Management Plan to meet the requirements in the City's permit.

9. What is the National Pollutant Discharge Elimination System (NPDES) Stormwater Program?

Polluted stormwater runoff is a leading cause of impairment to the nearly 40% of surveyed U.S. water bodies which do not meet water quality standards. Over land or via storm sewer systems, polluted runoff is discharged, often untreated, directly into local water bodies. When left uncontrolled, this water pollution can result in:

• The destruction of fish, wildlife, and aquatic life habitats
• A loss in aesthetic value
• Threats to public health due to contaminated food, drinking water supplies, and recreational waterways

10. What is a Municipal Separate Storm Sewer System (MS4)?

The regulatory definition of an MS4 (40 CFR 122.26(b)(8)) is "a conveyance or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains): (i) Owned or operated by a state, city, town, borough, county, parish, district, association, or other public body (created to 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 waters of the United States. (ii) Designed or used for collecting or conveying stormwater; (iii) Which is not a combined sewer; and (iv) Which is not part of a Publicly Owned Treatment Works (POTW) as defined at 40 CFR 122.2."

Examples of MS4s

In practical terms, operators of MS4s can include: 

• Correctional Facilities
• Military Bases
• Municipalities and Local Sewer Districts
• Public Hospitals
• Public Universities
• State and Federal Departments of Transportation

The Stormwater Phase II Rule added federal systems, such as military bases and correctional facilities by including them in the definition of small MS4s.