The Natural Resources Program helps maintain and promote a healthy environment in Wilsonville by providing long term care of local natural resources, such as streams, wetlands, and natural areas, the City is ensuring a sustainable future for the residents of Wilsonville.
What is stormwater?
Stormwater is runoff from rain and snowmelt which flows over the ground, driveways, streets, parking lots, and buildings that drains to streams, rivers, lakes, and the ocean.
Why should we be concerned with stormwater?
There are two main issues relating to stormwater runoff; one is the volume and intensity of the runoff water and the other relates to the potential contaminants that the water is carrying to a storm drain, lake, stream, wetland, or river.
What is stormwater management?
Stormwater management addresses delaying, capturing, storing, treating, or infiltrating stormwater runoff. The loss of wetland and floodplain areas along with the corresponding increase in impervious surfaces necessitates the active management of stormwater runoff through the use of structural controls, such as water quality facility and detention ponds, or other management measures within most urbanized areas.
Structural controls provide a means to manage the amount, intensity and contaminants contained 
within stormwater runoff. However, it is difficult to construct and operate a stormwater facility that will work as effectively as the natural system functioned prior to urbanization. Other measures that should be considered include, but are not limited to: restoring wetlands and floodplains, increasing the amount of typical and urban forest or native cover, reducing the amount of impervious cover, and minimizing our collective impact (e.g. responsible home and work practices) on any given watershed.
How is the City managing stormwater?
The Natural Resources Program works cooperatively with other city departments to plan and manage the drainage system in Wilsonville. The federal Clean Water Act, Safe Drinking Water Act, and Endangered Species Act direct the City to improve stormwater quality and protect watersheds, rivers, streams and drinking water resources.
Key elements of the city’s stormwater management program include:
- The Stormwater Master Plan– The Master Plan identifies areas of the city that currently experience erosion, flooding, and water quality problems, or that can be expected to experience such problems with future development. The Stormwater Master Plan Update is in progress.
- Public Works Standards (Section 3) – Public Works Standards (Section 3), outlines design and construction requirements for stormwater and surface water management. Provisions are intended to prevent or reduce adverse impacts to the drainage system and water resources. These requirements are intended to protect the beneficial uses, such as swimming, fishing etc., in the Willamette River.
- NPDES Permit - The federal Clean Water Act requires municipalities to obtain a National Pollutant Discharge Elimination System (NPDES) permit for stormwater discharges. The NPDES Permit link above takes you to a list of documents used in the application for the latest round of permit renewal.
- Stormwater Management Plan - The city’s Stormwater Management Plan (SWMP) is the means for complying with the NPDES permit and managing the city's stormwater system. All stormwater facilities on private property are maintained by the property owner or Home Owners Association.
- Total Maximum Daily Loads (TMDLs) - TMDLs define the amount of pollutants that can be present in a water body without causing water quality criteria to be exceeded.
Extensive water quality monitoring and modeling (for temperature, bacteria, and mercury) has been done to establish TMDLs for the Willamette River. In March of 2008 the City enacted its Willamette River TMDL Implementation Plan to ensure water quality protection of the Willamette River.
To report a clogged stormwater catch basin or pipe, contact Public Works at 503-682-4092 or fill out our online request form.