Low Impact Development



Rain garden in sidewalk

​Low Impact Development (also called LID) is a stormwater management approach with the basic principle to replicate nature: manage rainfall at the source using decentralized micro-scale stormwater treatment and storage facilities. LID's goal is to mimic a site's pre-development hydrology by using design techniques that infiltrate, filter, store, evaporate, and detain runoff close to its source. Green Infrastructure is another term being used with techniques similar to LID.

Starting in January 2016, Clark County regulations require that development projects utilize LID where feasible. Techniques such as preserving native vegetation, using permeable pavements and multiple small infiltration features, like bioretention swales, are required. These techniques treat stormwater runoff as a resource to recharge groundwater, support healthy plant growth and protect local creeks and streams.  Older design techniques tried to get water off a site as quickly as possible via piping systems to large centralized ponds. Those systems have limited treatment options to remove pollution and may cause scouring during large rain events.

Learn more about LID in our community:

  • Where is LID in Clark County - Visit our Southwest Washington Stormwater Partners web page for an interactive map of locations of various types of LID. More >>

  • Lots of training available - The state of Washington has a central resource for LID information, including LID overview presentations, technical training videos on design, construction and maintenance. More >>

    • Department of Ecology LID Resource page. More >>
    • Become certified LID Design or Operations/Maintenance with Ecology. More>>
    • Clark County has hosted a series of workshops and trainings for various audiences interested in learning more about LID in our community.
      • February 4, 2016 - Water Resources Education Center - Stormwater Manual and Code updates for Engineers.   Overview   Presentation

Learn more about Low Impact Development resources

VIsit our Stormwater Code and Manual web page.