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National Estuary Program (NEP)

How the National Estuary Programs Address Pathogens

Pathogens are disease-causing microorganisms such as viruses, bacteria and parasites that can create health risks for people enjoying recreation in and on the water. Pathogens can be introduced into estuaries from the following sources:

  • Inadequately treated sewage
  • Runoff from urban areas and animal operations
  • Medical waste
  • Boat and marina waste
  • Combined sewer overflows
  • Waste from pets and wildlife

Pathogens pose a health threat to swimmers, divers and seafood consumers.

NEP Approach/Success Stories

In this section:

Mobile Bay National Estuary Program (Mobile Bay NEP)

Several Mobile Bay NEP (located in Alabama) efforts resulted in measurable decreases in bacteria concentrations.

The Big Creek Lake Watershed is the source of drinking water for most Mobile County residents. Here, Mobile Bay NEP supported outreach efforts and funding for projects to reduce bacterial loadings. The primary targets of the reduction efforts were a local dairy and property owners with failed septic tanks.

The Program supported technical assistance and community workshops conducted by the Mobile County Soil and Water Conservation District. These efforts resulted in pathogen loading reductions in Big Creek. The Program also assisted the Alabama Department of Environmental Management in the developing a TMDL for pathogens for Juniper Creek.

Additionally, a primary focus of the Program’s outreach activities is Three Mile Creek in the City of Mobile, which was since delisted for pathogen-related impairment. The Program will continue to play a primary role in the development and implementation of a watershed management plan for Three Mile Creek that results in restoration of the watershed’s hydrology.

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Santa Monica Bay National Estuary Program (SMBNEP)

Population growth and uncontrolled development have had serious impacts on the water quality of Santa Monica Bay. For example, popular swimming beaches are often posted with warnings due to high pathogen levels. Also, significant amounts of trash and pet waste frequently wash from city streets into the bay during storm events.

The adverse impacts on water quality of pathogens from stormwater and urban runoff are well documented. The Santa Monica Bay Restoration Commission conducted a landmark epidemiological study in 1995 that provided, for the first time, indisputable scientific evidence linking health risks to swimming in urban runoff-contaminated waters.

Finding solutions to water quality impairments caused by pathogens requires an understanding of the sources of pathogens and how these pollutants reach the bay and affect resources.

The sources of pathogens are numerous and disparate. Ultimately, however, they are a product of all the people, and their pets, that live in the bay's watershed. Moreover, pathogens reach the bay via numerous pathways, including the following:

  • Runoff from lawns and streets into creeks and storm drains
  • Municipal wastewater
  • Commercial discharges
  • Boating and shipping activities

Urban and stormwater runoff carried to the bay through the region's 5,000-mile storm drain network is a serious, year-round concern. In fact, each year sees an average of 30 billion gallons of runoff discharged through more than 200 outlets. Even in dry weather, 10 to 25 million gallons of water flow through storm drains into Santa Monica Bay every day.

And since the network was designed to convey flood waters to the ocean rapidly, all wet-weather flows and most dry-weather flows bypass wastewater treatment facilities and discharge directly to the bay. Reducing pathogen levels in the bay is a key goal of the Santa Monica Bay Restoration Plan, which emphasizes preventing pollution at the source and targeting specific areas for pollution reduction.

Stormwater and urban runoff are regulated through municipal, industrial and construction National Pollutant Discharge Elimination System (NPDES) permits. Required under the Clean Water Act, the NPDES Stormwater Program is a comprehensive national program for addressing sources of stormwater discharges that adversely affect the quality of our waters.

The Program uses NPDES permits to require the implementation of measures to reduce the amounts of pathogens carried by stormwater runoff into local water bodies. Permit holders must develop and implement Stormwater Pollution Prevention Plans or Stormwater Management Programs using Best Management Practices (BMPs) to prevent the discharge of pollutants into the bay.

These efforts will improve the water quality of the bay to ensure that the waters are swimmable and fishable, the ultimate goal of the Clean Water Act.

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