The Effectiveness of Rain Gardens as a Low-Impact Development Strategy for Storm Water Pollution Reduction in Western Washington

Date of Award


Document Type

Undergraduate Capstone Project

Degree Name

Master of Applied Science

Organizational Unit

University College, Environmental Policy and Management


Environmental Policy & Mgmt

First Advisor

Harold Tyus


Bioretention, Low-impact development, Rain gardens, Stormwater management, Stormwater runoff, Water quality


Stormwater runoff is a major cause of surface water pollution in western Washington and cost-effective control measures are needed to reduce contamination of receiving waters. This project evaluated the performance efficiency and costs of installing a residential rain garden by inspecting two gardens and testing water quality samples in one. Infiltration through the garden was effective in reducing metals and nutrients as indicated by reductions in copper and nitrate concentrations of 75% and 97%, respectively. The costs were affordable for most homeowners and cost-effective compared to other options. After doing on-site investigations, the storm water manual for the State of Washington was reviewed and eight recommendations were made for improving it.

Publication Statement

Copyright is held by the author. Permanently suppressed.

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