Summary and Background
Above-average rainfall caused localized flooding in Salmon Creek Basin in the rainy seasons of 1996-97
and 1998-99. On some properties, the groundwater surfaced as puddles; on others, the water formed lake-like conditions that covered several acres. Property owners experienced a range of inconveniences - from
high water around and under homes, to failed septic systems, contaminated drinking water, and restricted
access to property.
A comprehensive study of the area was completed in late 1999. A multi-jurisdictional plan, the Salmon Creek Comprehensive Drainage Basin Plan was completed and adopted in the early 2000s by the governing jurisdictions.
Location of Basin
Salmon Creek Basin is located in Thurston County, Washington, just south of the Olympia Regional
Airport and the Tumwater City limits. The basin is relatively flat and slopes gently toward Salmon
Creek, which flows into Black River. The basin boundary encompasses approximately 12 square
miles (7 ,500 acres) from the Tumwater City Limits on the northern boundary, to 113th Avenue on its
southernmost edge. The western boundary lies along Littlerock Road, and the eastern boundary extends
just past Brooks Lane. The area of the basin is defined by the surface and groundwater sources that
contribute to recharge of Salmon Creek.
Appendix E (30 MB)
Tumwater Resolution R2004-012 (<1 MB)
Tumwater Ordinance O2005-003 (<1 MB)