Introduction to Low Impact Development

Application of Low Impact Development (LID) Principles

Consistent with the Model WQMP, a Project WQMP may include:

  • Site design measures
  • Low Impact Development (LID) Best Management Practices (BMPs)
  • Participation in sub regional/regional BMPs
  • Hydromodification BMPs
  • Use of alternative programs or treatment control BMPs, and
  • Applicable source control BMPs
  • Three Examples of Creative Stormwater Management Solutions

A key component of sustainable design is low impact development (LID), a land planning and engineering design approach for managing stormwater runoff. One of the most cost-effective LID strategies is "disconnection," which decouples roof downspouts, roadways and other impervious areas from stormwater conveyance systems. Its primary objective is to reduce the amount of runoff leaving the site, which it accomplishes by collecting and managing stormwater on-site or dispersing it into the landscape.

The updated Model WQMP was approved by the SARWQCB on May 19, 2011 and became effective on August 17, 2011. To assist with compliance with the SARWQCB permit requirements and to explain aspects of the Model WQMP, a Technical Guidance Document (TGD) is available for project proponents. Project proponents should also refer to Section 7.II–2.0 of the Model WQMP document for Project WQMP Requirements including structural, non-structural and LID BMPs.

A TGD has been prepared as a companion to this Model WQMP. The TGD contains more detailed information and explains how to complete the requirements and the technical analysis necessary for preparing a Conceptual or Preliminary WQMP, or Project WQMP. Please refer to the document as you prepare the Water Quality Management Plan.

Low Impact Development (LID) Standards

The new NPDES Permit requires the inclusion of low impact development (LID) standards into the design of new development or redevelopment projects. These concepts are intended to reduce the amount of impervious areas and prevent stormwater runoff from flowing off of an improved parcel.

If you plan to construct a project in the City of Cypress, you must incorporate LID concepts into the project design. While preparing for the design of your project, please download and review the document "Low Impact Development for Southern California." Keep in mind that the document should only be used as reference when developing a WQMP. The LID concepts selected shall conform to the requirements of the Model WQMP and the Technical Guidance Document.

Low Impact Development (LID) “Barrier Busters” Fact Sheet Series

The seven-part fact sheet series explains the benefits of low impact development (LID) in clear terms and gives thorough examples. These fact sheets directly address some concerns that have been raised about adopting LID, including topics related to benefits, terminology, costs, aesthetics, effectiveness, and maintenance of LID.

Please visit the following link for more information:
http://water.epa.gov/polwaste/green/bbfs.cfm

In summary, this is a manual of practice for LID that provides:

  • Details on how to use LID Principles and LID Best Management Practices (BMPs) to reduce the impacts of land development or re-development on water resources at the project level.
  • Guidance for municipalities, land use planners, land developers, consultants, design professionals who prepare stormwater engineering plans and specifications, and others in private industry and public service.
  • A site planning and design reference that will facilitate the implementation of LID for projects in Southern California. It is designed to complement the Stormwater BMP Manual(s) that have been developed and updated by the California Stormwater Quality Association (CASQA).
  • A tool that can be applied at the project level for the development of integrated water and stormwater management regulatory compliance and resource protection programs.

LID options that mimic natural processes to retain and use stormwater are preferred. By promoting infiltration, evapotranspiration, and harvesting throughout the landscape, green infrastructure preserves and restores the natural water balance. To learn more about the various available applications please click on the document: "Green Infrastructure in Arid and Semi-Arid Climates".

As noted above, all LID concepts considered for inclusion in development projects should conform to the requirements of the 4th Term NPDES Permit as well as the Model WQMP and Technical Guidance Document. The Model WQMP and Technical Guidance Document is also available for viewing and downloading at www.ocwatersheds.com. It is also recommended that proponents review Section XII of the 4th Term NPDES Permit for New Development/Redevelopment requirements.

Infiltration Practices for New Development/Redevelopment

There are stormwater infiltration practices which could provide benefits and best management practices at vacant parcels and brownfield sites. It assists communities, developers, and other stakeholders to determine the appropriateness of these practices. The benefits involve decreasing stormwater infrastructure costs, increasing groundwater recharge, and decreasing stormwater runoff.

To learn more about how to implement stormwater infiltration practices at your vacant parcel or brownfield site, please visit: Implementing Stormwater Infiltration Practices at Vacant Parcels and Brownfield Sites.

City of Cypress Department of Public Works ~ 5275 Orange Avenue ~ Cypress, CA 90630 ~ 714-229-6740