Storm Water Program Background | Region 10 | US EPA

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Storm Water Program Background


Background
Phase I Storm Water Requirements
Is Runoff from Agricultural or Timber Harvest Activities Regulated?
Phase II Storm Water Requirements
Small Community Exemption Expires in 2003
Why are Storm Water Discharges from Urban Areas a Problem?
Why are Storm Water Discharges from Construction Activity a Problem?
EPA Region 10's Storm Water Web page

Return to Region 10 Tribal Storm Water Web page



Background
Storm runoff is major source of pollution to surface water. Runoff from certain sources are subject to regulation by the federal Clean Water Act’s (CWA) National Pollutant Discharge Elimination System (NPDES) program, when such runoff is discharged directly to surface water.

According to the 1996 National Water Quality Inventory (Inventory), a biennial summary of water quality surveys, approximately 40 percent of surveyed U.S. waterbodies are still impaired by pollution and do not meet water quality standards. A leading source of this impairment is polluted runoff. In fact, according to the Inventory, 13 percent of impaired rivers, 21 percent of impaired lake acres and 45 percent of impaired estuaries are affected by urban/suburban storm water runoff and 6 percent of impaired rivers, 11 percent of impaired lake acres and 11 percent of impaired estuaries are affected by construction site discharges.


Phase I Storm Water Requirements:
Phase I of the EPA storm water program was promulgated in 1990 under the CWA. Phase I relies on National Pollutant Discharge Elimination System (NPDES) permit coverage to address storm water runoff from the sources listed below:

(1) “large” municipal separate storm sewer systems (MS4s) generally serving populations of 100,000 or greater,
(2) construction activity disturbing 5 acres of land or greater, and
(3) ten categories of industrial activity.


You will need Adobe Acrobat Reader, available as a free download, to view some of the files on this page. See EPA's PDF page to learn more about PDF, and for a link to the free Acrobat Reader.


Region 10 developed a short brochure on the current construction permitting requirements for construction projects in Indian Country



Is Runoff from Agricultural or Timber Harvest Activities Regulated?
No. The Clean Water Act does not regulate runoff from agricultural or silvicultural/timber activities. However, if a particular property is being converted from forestry or farming to any other use (such as to build a residence or permanent access road) the storm water discharge permitting requirements may apply.


Phase II Storm Water Requirements
The Storm Water Phase II Final Rule is the next step in EPA’s effort to preserve, protect, and improve the Nation’s water resources from polluted storm water runoff. The Phase II rules expand the Phase I program by requiring operators of smaller MS4s in urbanized areas and operators of small construction sites (1-5 acres), to implement programs and practices to control polluted storm water runoff through the use of NPDES permits. Phase II is intended to further reduce adverse impacts to water quality and aquatic habitat by instituting the use of controls on the unregulated sources of storm water discharges that have the greatest likelihood of causing continued environmental degradation. The environmental problems associated with discharges from MS4s in urbanized areas and discharges resulting from construction activity are outlined below.


Small Community Exemption Expires in 2003
Many tribal governments and other small communities are unfamiliar with the Phase I storm water permiting requirements for industrial and construction activity. Provisions within the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991 temporarily delayed the deadline for industrial activities operated by municipalities with populations of less than 100,000 people to obtain an NPDES storm water discharge permit. The exemption included all small municipal governments, including Tribal entities. Congress delayed the permitting deadline for these facilities to allow small municipalities additional time to comply with NPDES requirements. The Phase II Final Rule ended this temporary exemption from permitting and set a deadline of no later than March 10, 2003 for all ISTEA-exempted municipally operated industrial activities to obtain permit coverage.

Therefore, after March 2003, all industrial operations, construction projects and municipal storm sewer systems must comply with the NPDES storm water permit requirements, regardless of whether the activity is publically or privately owned.


Why are Storm Water Discharges from Urban Areas a Problem?
Storm water discharges from MS4s in urbanized areas are a concern because of the high concentration of pollutants found in these discharges. Concentrated development in urbanized areas substantially increases impervious surfaces, such as city streets, driveways, parking lots, and sidewalks, on which pollutants from concentrated human activities settle and remain until a storm event washes them into nearby storm drains. Common pollutants include pesticides, fertilizers, oils, salt, litter and other debris, and sediment. Another concern is the possible illicit connections of sanitary sewers, which can result in fecal coliform bacteria entering the storm sewer system. Storm water runoff picks up and transports these and other harmful pollutants then discharges them – untreated – to waterways via storm sewer systems. When left uncontrolled, these discharges can result in fish kills, the destruction of spawning and wildlife habitats, a loss in aesthetic value, and contamination of drinking water supplies and recreational waterways that can threaten public health.


Why are Storm Water Discharges from Construction Activity a Problem?
Uncontrolled runoff from construction sites is a water quality concern because of the devastating effects that sedimentation can have on local waterbodies, particularly small streams. Numerous studies have shown that the amount of sediment transported by storm water runoff from construction sites with no controls is significantly greater than from sites with controls. In addition to sediment, construction activities yield pollutants such as pesticides, petroleum products, construction chemicals, solvents, asphalts, and acids that can contaminate storm water runoff. During storms, construction sites may be the source of sediment-laden runoff, which can overwhelm a small stream channel’s capacity, resulting in streambed scour, streambank erosion, and destruction of near-stream vegetative cover. Where left uncontrolled, sediment-laden runoff has been shown to result in the loss of in-stream habitats for fish and other aquatic species, an increased difficulty in filtering drinking water, the loss of drinking water reservoir storage capacity, and negative impacts on the navigational capacity of waterways.

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URL: http://yosemite.epa.gov/R10/WATER.NSF/NPDES+Permits/SW+Background+-++IC+Fact+Sheet

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