Preventing Pollution & Runoff

What You Need To Know About Stormwater

Storm water runoff from lands modified by human activities can harm surface water and, in turn, cause or contribute to poor water quality by changing natural hydrologic patterns, accelerating natural stream flows, destroying aquatic habitat, and elevating pollutant concentrations and loadings.

Such runoff may contain high levels of contaminants, such as sediment, suspended solids, nutrients (phosphorus and nitrogen), heavy metals, pathogens, toxins, oxygen-demanding substances (organic material), and floatables (U.S. EPA. 1992. Environmental Impacts of Storm Water Discharges: A National Profile. EPA 841-R-92-001. Office of Water. Washington, DC).

After a rain, storm water runoff carries these pollutants into nearby streams, rivers, lakes, estuaries, wetlands, and oceans. Individually and combined, these pollutants impair water quality, threatening designated beneficial uses and causing habitat alteration and destruction.

Stormwater Protection At Home
The most common source of water pollution is runoff from lawns, roads, and agricultural land. Impervious surfaces like driveways, sidewalks, and streets prevent water from naturally soaking into the ground.
Problems occur when debris, chemicals, dirt, and other pollutants flow into stormwater systems or directly to streams, rivers, wetlands, and lakes. Anything entering these systems is discharged untreated into the waterbodies we use for swimming, fishing, and providing drinking water.
Common pollutants include oil and grease from roadways; pesticides, lawn clippings, dog waste, and leaves from lawns; and carelessly discarded trash, such as cigarette butts, wrappers, and plastic bottles. A few ways for you to help minimize this pollution are:
  • Compost or mulch yard waste. Do not sweep it into the street or storm drains.
  • Remember to pick up and dispose of pet waste properly, especially when out for a walk.

Illicit Discharge Into Stormwater Systems
Studies have shown that discharges from a storm drain system often include wastes and wastewater from non-stormwater sources, referred to as illicit discharges. These discharges are ‘illicit’ because municipal storm sewer systems are not designed to accept, process, or discharge such wastes.

Sources of illicit discharges can include sanitary wastewater illegally connected to the storm drain system; effluent from septic tanks; car wash, laundry, and other industrial wastewaters; improper disposal of auto and household toxics, such as used motor oil and pesticides; and spills from roadways.

Illicit discharges enter the system through either direct connections (e.g., wastewater piping either mistakenly or deliberately connected to the storm drains) or indirect connections (e.g., infiltration from cracked sanitary systems, spills collected by drain outlets, and paint or used oil dumped directly into a drain). The result is untreated discharges that contribute high levels of pollutants, including heavy metals, toxins, oil and grease, solvents, nutrients, viruses and bacteria into receiving waterbodies.

The City of Mandan is required to periodically inspect the stormwater system and reports as necessary on existing conditions. Do what you can to eliminate illicit discharge through proper maintenance and never dump or allow dumping into gutters or inlets.

This information and more is available through City Engineering and on the EPA website.

 

Construction Site Runoff Control
The North Dakota Department of Health requires construction sites of 1 acre in size and larger to attain permits for land disturbance. The required steps to attain this permit are:
  • Submit a Notice of Intent (NOI);
  • Develop and implement a Storm Water Pollution Prevention Plan (SWPPP). The SWPPP includes erosion and sediment controls, controls on waste at the site, self-inspection/monitoring, and reporting efforts; and
  • Submit a Notice of Termination (NOT) when permit coverage is no longer
  • necessary.

The City of Mandan adopted an ordinance in August, 2006 which also requires a stormwater plan to be submitted to the city for approval before building permits or plats may be approved. This ordinance satisfies part of the EPA’s MS4 requirements. The combination of these requirements is to ensure that the minimum possible contamination of runoff will come from construction sites.

This information and more is available through City Engineering and on the EPA and Department of Health websites: 

http://www.ndhealth.gov/

https://www.epa.gov/npdes/stormwater-discharges-municipal-sources

 

 

Post-Construction Stormwater Management
Post-construction storm water management in areas undergoing new development or redevelopment is necessary because runoff from these areas has been shown to significantly effect receiving waterbodies. Many studies indicate that prior planning and design for the minimization of pollutants in post-construction storm water discharges is the most cost-effective approach to storm water quality management.

The City of Mandan adopted an ordinance in August, 2006 which requires a stormwater plan to be submitted to the city for approval before qualifying building permits or plats may be approved. This ordinance includes requirements for runoff protection for post-construction as well as during construction.

This information and more is available through City Engineering and on the EPA and Department of Health websites.

 

Stormwater Protection - City Housekeeping
The Pollution Prevention/Good Housekeeping measure for municipal operations is a key element of the small MS4 storm water management program. The North Dakota Department of Health requires the City of Mandan to examine and subsequently alter actions to help ensure a reduction in the amount and type of pollution that
  1. collects on streets, parking lots, open spaces, and storage and vehicle maintenance areas and is discharged into local waterways; and
  2. results from actions such as environmentally damaging land development and flood management practices or poor maintenance of storm sewer systems. 

This measure is meant primarily to accomplish the goal of improving or protecting the quality of receiving waters by altering the performance of municipal or facility operations. Mandan meets these requirements through training of employees, proper vehicle maintenance, re-using street sanding material, and periodically inspecting containment sites.

This information and more is available through City Engineering and on the EPA and Department of Health websites.