Stormwater Fact Sheet

All of the storm water in the City of West Linn that is collected by curb inlets and catch basins, drains to local streams.

The average annual rainfall in West Linn is 47.060 inches. Approximately 75% of the total precipitation occurs during the 6 months between October and March.

There are approximately 107 miles of storm lines, 2500 catch basins, 105 Pollution Control Manholes, 40 Ponds and 54 underground detention tanks that are maintained by the City's storm water crew each year.

Currently, approximately 42% of the total land area of the city is covered by impervious surfaces (e.g., streets, roofs and sidewalks).

The City monitors surface water quality at Trillium Creek, Johnson Creek and Tanner Creek. These locations were chosen because they are located at the bottom of three large drainages within the City and provide good geographical representation of the City. Samples are collected four times during the wet weather period (Oct. 1-April 30) and twice during the dry period (May 1-Sept. 30).

To protect the waters in our region, the city is in the process of enhancing its commercial storm water pollution control program. The goal of this program is to reduce the amount of pollutants entering private and public storm drains because these systems discharge to nearby streams.

In an effort to educate business owners, we visit all of the following types of West Linn businesses: grocery stores, restaurants, gas stations, car washes, oil lubes/auto repair shops, nurseries, etc. We look at their storm water facilities and practices and offer suggestions that will help improve the quality of water that is being released from these facilities.

If you would like more information, call 503-722-5500.