Upstream development caused severe winter and spring flooding that eroded stream banks and channels, choking the stream with sediment and allowing non-native plants like blackberries to replace salmon-friendly native vegetation. By the early 1990s, the Spring Valley stretch of Hylebos Creek was inhospitable to native salmon.

A privately-owned bridge in the same area was damaged from the flooding and threatened to collapse into the stream.

In 1997, the City of Federal Way Surface Water Management Department stabilized the stream bed and streambank and added several large log structures to the stream, creating new pool habitat.

Volunteers with Friends of the Hylebos followed up with several planting projects, replacing invasive Himalayan blackberry with native trees and shrubs which will provide shade for salmon and habitat for native birds and wildlife.

Earth Day 2001, volunteers turned out to remove invasive weed species from previous plantings and plant new native trees and shrubs at Hylebos Creek During Several events over 3 years, volunteers planted native trees and shrubs to shade Hylebos Creek and provide healthier salmon habitat