Integrating Low-Impact Development
into the Thurston County Code
New Stormwater Standards Underway
Thurston County is among many counties and cities required to make “Low-Impact Development,” or LID, the preferred and commonly used approach to site development. LID is a stormwater management strategy that is designed to minimize impervious surfaces, maximize native vegetation retention, and filter stormwater on site as much as possible.
Regulatory Framework for Updating Codes
In mid-2014, TRPC began helping Thurston County review its codes, plans and standards and consider ways to encourage LID practices, per the Phase II Western Washington Municipal Stormwater Permit requirement to make LID the “preferred and commonly used approach to site development.”
The project team gathered input from several other workgroups and broader public outreach efforts through 2015 and drafted code and plan revisions for policymaker consideration. The Thurston County Board of County Commissioners adopted the code changes in late 2016.
The primary stormwater management objective of LID is to approximate pre-development (native) forest conditions (or prairie condition if historic records indicate that as the native setting) over the full range of rainfall intensities and durations.