Low Impact Development

Updated Stormwater Management Regulations

LID Business Case Analysis for Urban Centers

The City continues to research how to best integrate LID on-site management within the City's two urban centers (Downtown and Overlake). This analysis may result in further modifications to how low impact development is implemented in those areas.

The goal of this analysis is to make better informed decisions. Redmond must continue to protect the environment and meet state stormwater requirements. We also recognize our downtown—in particular—is a complex location in which to construct development projects due to factors such as the degree of urbanization, a high groundwater table, and the fact that this groundwater supplies Redmond with a third of its drinking water. The findings of this analysis will be used to generate recommendations to our City Council and may result in additional policy direction or updates to City Code or the Stormwater Technical Notebook.

Low Impact Development Urban Centers Analysis: Description, Study Questions, and Schedule
LID Business Case Focus Group Process Map

To support business case analysis the City of Redmond has conducted a number of technical investigations. Information from these analyses will be brought into and used within the larger LID Business Case Analysis.  The following links provide information regarding these technical investigations.

The Technical Investigation “Crosswalk” table offers information linking these technical investigations and technical criteria to the study questions that have been developed to direct and frame the larger LID Business Case Analysis.

In addition, City of Redmond Staff drafted the following technical memos to capture the methodologies used during these investigations.  (Unless a memo bears an engineering stamp or is noted as “final”—the memo is in draft form and may be updated.)

May 18, 2017 Draft Technical Memo - Environmental Impacts of Stormwater Policy
May 18, 2017 Draft Technical Memo - Stormwater Infiltration Downtown
May 18, 2017 Draft Technical Memo - Stormwater Capacity Analysis – Downtown
May 18, 2017 Draft Technical Memo - Downtown Stormwater Runoff Treatment Analysis
May 25, 2017 Overlake Village Modeling Update - Scenario Results & Assumptions
June 8, 2017 Draft Technical Memo - Development Prototype Analysis
June 9, 2017 Abstracts of All Technical Memos
June 9, 2017 Technical Memo - Overlake Regional Stormwater Capital Facility
June 9, 2017 Technical Memo - Overlake Regional Stormwater Operations and Maintenance Effort
June 9, 2017 Technical Memo - Site Infiltration Capital and Maintenance Considerations
August 8, 2017              Social, Economic, & Environmental Considerations Within the LID Business Case Analysis
August 9, 2017 Technical Memo - Draft - Evaluation of Infiltration On-Site, Regionally, and in the Right-of-Way

Stormwater Technical Notebook, Version 7A

A NEW VERSION of the Stormwater Technical Notebook, Version 7A, was approved by the City and made effective March 1, 2017. 

This new version of the notebook simplifies language regarding the requirements for Low Impact Development (LID) on-site stormwater management at new and re-developing project sites.

Stormwater Technical Notebook, Version 7, approved on December 28, 2016, adopted the 2014 Ecology Stormwater Manual, implemented low impact development requirements citywide (in compliance with the City’s NPDES permit), and provided language for use of the “special purpose zoning district“ competing needs clause within the City’s two urban centers.

Upon review, the City determined that the “special purpose zoning district” competing needs language was not needed and caused confusion. LID is required at all applicable project sites, unless it is determined to be infeasible according to the 2014 Ecology Manual’s infeasibility criteria.

LID-related Zoning Code

Amendments, were adopted by the Redmond City Council on December 7, 2016: Zoning Code

Municipal Code

NPDES-related Amendments, were adopted by the Redmond City Council on December 7, 2016:

RMC 13.06 was updated on December 6, 2016, by Ordinance 2859.

RMC 15.24 was updated on December 6, 2016, by Ordinance 2860(AM).

LID Integration Process Report

Summary of the citywide LID code review and revision process

Contact Information

Redmond Zoning Code Amendments
Peter Holte -  425-556-2822

Redmond Municipal Code Amendments
Andy Rheaume - 425-556-2741

Stormwater Technical Notebook Updates
Steve Hitch, PE, Senior Stormwater Engineer - 425-556-2891 

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