Low impact development (LID) is a stormwater management strategy that emphasizes conservation and use of existing natural site features integrated with distributed, small-scale stormwater controls to more closely mimic natural hydrologic patterns in residential, commercial, and industrial settings. LID employs principles such as preserving and recreating natural landscape features and minimizing impervious surfaces to create functional and appealing site drainage that treat stormwater as a resource rather than a waste product. Practices that adhere to these LID principles include bioretention facilities, rain gardens, vegetated rooftops, rainwater harvesting (rain barrels and cisterns), and permeable pavements.
This webpage includes information on two LID practices: rain gardens and rainwater harvesting, including associated stormwater rate reductions.
The following resources address low impact development techniques.
- Developing Low Impact Development (LID) Standards, Washington State Department of Ecology - Results of state advisory committee process, 2009-2011
- Green Roofs for Healthy Cities, Green Roof Infrastructure Industry Association - Extensive information on green roof systems
- Low Impact Development, U.S. EPA - Includes LID factsheets and reports, design guidance manuals, and other information resources
- Low Impact Development Center - Nonprofit organization dedicated to the advancement of low impact development technology; includes publications, rain garden template, green highways, and green infrastructure
- Low Impact Development: An Alternative Approach to Site Design, by Asa Foss, PAS Memo, May/June 2005 (Available through MRSC Library Loan)
- Low Impact Development, Technical Guidance Manual for Puget Sound ( 18 MB), WSU and Puget Sound Partnership,12/2012 - Includes guidelines for low impact development practices and research and data related to those practices to help inform decision making when adapting LID applications to local jurisdictions
- Stormwater & Low Impact Development (LID), Puget Sound Partnership - Basic information about the benefits of LID
- Urban Design Tools for Low Impact Development, Low Impact Development Center - Provides watershed managers with tools and techniques that can be used to meet regulatory and receiving water protection program goals for urban retrofits, re-development projects, and new development sites
Sample Local Government Provisions
This section includes sample regulations and information on LID from Washington cities and counties.
- Bellingham Low-Impact Development - Includes native plant guide and information on rain gardens and rain barrels
- Bothell Low Impact Development Report, 2011 - This document is intended to help identify barriers for LID implementation and establish goals and metrics to promote and measure the use of LID techniques
- Edmonds Sustainability Low Impact Development - Links to several LID-related documents
- Fife Green Factor, Low Impact Development - Includes ordinance and Green Factor worksheets
- Kirkland Low Impact Development, Surface Water - Includes tools and requirements for surface water development and LID elements, such as pervious pavement, green roofs, rain barrels, and rain garden
- Mercer Island Low Impact Development - Basic LID information
- Port Angeles Municipal Code Ch. 17.44 - Planned Low Impact Development Overlay Zone
- Redmond Low Impact Development - Information about LID policies and projects
- Spokane Ordinance No. C35021, adopted 09/03/2013 - Regarding low impact development provisions
A rain garden is a shallow planted area in the landscape where rainwater is allowed to collect and absorb back into the soil. A rain garden mimics the undisturbed conditions of the natural environment. This section includes information on rain garden design.
- Bothell Rain Gardens - Demonstration Rain Garden-King County Library and facts about rain gardens
- Pierce County Rain Gardens - Includes rain garden handout and other resources
- Puget Sound Rain Gardens, WSU Extension, Snohomish County - Includes general rain garden information and links to rain garden resources in Puget Sound counties
- Puyallup Rain Gardens
- Rain Garden Handbook for Western Washington, Washington State Department of Ecolog - Designing landscape to protect streams, lakes, bays, and watersheds, 6/2013
- Seattle Building a Rain Garden to slow and filter roof or driveway runoff, RainWise factsheet, Seattle Public Utilities, revised 3/2011
- Tacoma Rain Gardens - Basic information on rain gardens
Rainwater harvesting for irrigation involves collecting the water that falls on a roof in a rain barrel or cistern and using it for watering lawns and gardens. Rainwater harvesting conserves water and can reduce the impact of heavy storm flows on streams, lakes, bays, and watersheds. The following is some information from communities in Washington State.
Statutes Allowing Reduction of Stormwater Charges
The following state statutes allow for possible rater reductions for new or remodeled commercial buildings that use permissive rainwater harvesting systems.
Sample Ordinances - Stormwater Rate Reductions for Rainwater Catchment Systems
- Kitsap County Ordinance No. 315-2004 - Amends Kitsap County Code Sec.12.40.050 to establish a surface and stormwater management program rate reduction for permissive rainwater harvesting systems, infiltration systems, and direct discharge systems, passed 04/12/2004
- Snohomish County Ordinance Nos. 05-102 and 05-103 provide reductions in surface water management rates and charges for commercial properties with approved rainwater harvesting systems, passed 10/2005
- Rainwater Harvesting, Oregon Smart Guide, Oregon Department of Consumer and Business Services, Building Codes Division - Useful introductory guide to rainwater harvesting
- Rainwater Harvesting: Moderate Investment Can Yield Big Results, by Doug Pushard, OnTap, Summer 2008 - Overview of rainwater harvesting
- Rainwater and Stormwater Harvesting, Sustainable Cities Institute - Describes basic components of a rainwater harvesting system
- The State of Rainwater Harvesting in the U.S, by Tammie Stark and Doug Pushard, On Tap, Fall 2008 - Review of rainwater harvesting regulations
- Rainwater Harvesting - Conservation, Credit, Codes, and Cost Literature Review and Case Studies , US EPA, 01/2013 - Information for states and other governments for developing and implementing rainwater harvesting programs