DEEP: Urban Sources Management Measures

Connecticut's Coastal Nonpoint Source Pollution Control Program

Urban Sources

Urban areas in Connecticut present the greatest nonpoint source-related threat to Long Island Sound.  The conversion of undeveloped land for new residential, commercial or industrial uses, or for roads, highways, and bridges, can cause or increase site erosion both during and after construction.  Poorly planned development can also increase stormwater runoff volumes and velocity when vegetated areas are paved or covered with buildings.  Stormwater running over urban areas can collect sediments, nutrients, road salts, heavy metals, petroleum hydrocarbons, and pathogens, and transport them into local watercourses and Long Island Sound.   Additionally, poorly maintained or improperly operated septic systems can introduce pathogens to ground water and surface waters, while perfectly functioning conventional systems can contribute nutrients to those waters.

Since urban nonpoint sources of pollution are so closely related to land use, municipal land use authorities play a central role in implementing this component of Connecticut’s CNP.  Workshops and other technical assistance are available to management area towns to help identify the existing tools available to implement the CNP.  These tools include:

  • the stormwater management, vegetated buffers and watershed management planning fact sheets contained in the Connecticut Coastal Management Manual;
  • recommended revisions to municipal plans of conservation and development and/or zoning and subdivision regulations to address nonpoint source pollution.  
  • model ordinances and examples of Connecticut-based stormwater ordinances contained in Appendix C of the 2004 Connecticut Stormwater Quality Manual; and
  • a model site plan application form and model instructions that focus on controlling nonpoint source pollution and stormwater.  The application form can be downloaded and modified to reflect individual municipal goals and objectives.  The application form provides for municipal review of stormwater plans for projects disturbing between 1 and 5 acres, in accordance with Phase II Stormwater requirements; asks applicants to determine if their project site contains or is adjacent to impaired waterbodies; and asks applicants to describe how proposed stormwater management practices will be consistent with the 2004 Connecticut Stormwater Quality Manual.

Key Concepts

  • Minimize adverse resource impacts.

  • Require proper site design.

  • Require the use of Best Management Practices (BMPs).

  • Provide for non-infringement buffers between site disturbance and resources.

  • Restore degraded habitats where possible.

  • Treat the “first flush” of runoff, considered to contain the greatest amount of pollutants.

  • Where suitable, retain onsite the volume of runoff generated by the first inch of rainfall.

  • Reduce impervious cover wherever possible, and “retrofit” existing paved areas.

  • Maintain post-development runoff rates and volumes at pre-development levels.

  • Once site is stabilized after construction, reduce the average annual total suspended solid loadings by 80 percent (or ensure that average annual total suspended solids loadings are no greater than predevelopment loadings).

  • Ensure that septic systems are properly designed, located, constructed, operated and maintained.

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