Water Quality Management Plan

Plan Purpose

The purpose of a Water Quality Management Plan (WQMP) is to achieve a level of storm water runoff pollution prevention and abatement that would ensure the health of our local waterways and beaches. The WQMP prescribes post-construction Best Management Practices (BMPs) for the property to accomplish this goal.

Exempt from Submittal of a Plan

All new development/redevelopment projects require a WQMP. However, the following are exempt from the submittal of a WQMP, unless the City determines that the project may result in the discharge of significant levels of a pollutant into a tributary to the stormwater drainage system:

  • Construction of a single family detached residence 5,500 square feet or less of interior space including garage
  • Improvements to a single family detached residence that will result in a total of 5,500 square feet or less of interior space including garage and additions, or addition of a second story with no increase in the footprint or improvements that will add no more than 25% of existing footprint and will not exceed 1,000 square feet of additional space

Priority & Non-Priority Projects

The City will determine whether or not the project is a Priority Project or a Non-Priority Project. The scope of the WQMP will differ depending on its priority, and report templates for both are provided for your use. A Model WQMP and Technical Guidance Document was developed in 2011 to assist project applicants in preparing WQMPs, which may include but are not limited to;

  • Applicable source control BMPs
  • Hydromodification BMPs
  • Low Impact Development (LID) BMPs
  • Site design measures and hydrologic source controls

Low Impact Development

Projects must incorporate Low Impact Development (LID) principles (PDF) in their design as part of their WQMP requirements. Priority projects will be required to infiltrate, harvest-and-reuse, evapotranspire, or biofiltrate the 85th percentile storm event on-site. 

Hydromodification Management

Hydromodification management has also emerged as a prominent issue in stormwater runoff management. Hydromodification is defined as the physical degradation or change in channels associated with alterations in flow and sediment due to proposed land-use alteration. The goal of hydromodification management is to integrate hydrologic controls into a proposed project such that post-development 2 year peak flows do not exceed pre-development conditions. 

Reducing hydromodification and its effects can protect and restore beneficial uses of receiving waters, hence its importance in water quality land development requirements.