Stormwater Management

Developers are required by state and federal law to manage stormwater to prevent water pollution and flooding. Typically, a highway project deals with stormwater management by constructing large stormwater detention ponds. While meeting the technical requirements of the law, engineered ponds fail to replicate the natural hydrology of a floodplain and are biologically sterile.

Moreover, ponds simply wouldn't work in the Lower Hylebos Creek Floodplain where they would displace existing floodplain storage capacity and during floods, be under water.

Instead the SR 167 project will rely on restoring the natural floodplain around Hylebos Creek. Nature has been doing flood management for millennia, so it makes sense to use this natural approach, which will be more cost-effective than detention ponds, and will provide significant habitat value, as well.

The project will use a series of water quality treatment techniques, including wetland bioswales, composted medians and infiltration gallerys, to protect local water quality.

Stream and Wetland Mitigation

When a development project damages or destroys stream or wetland habitat, the developers are required to "mitigate" the loss by creating or restoring like habitat elsewhere. The SR 167 Project will impact reaches of Hylebos Creek and its Surprise Lake Tributary, as well as destroy wetlands in the project area.

The Friends has worked with WSDOT to identify stream and wetland mitigation  tat will provide greatly enhanced conditions for local salmon and wildlife than the resources being affected.

Years ago, Hylebos Creek was artificially moved to a ditch between I-5 and Pacific Highway South near the Fife curve of I-5. This channel is commonly referred to as the Death Ditch because of its poor habitat conditions. Much of the stream in this area looks like Death Ditch. The SR 167 project will relocate the stream to a salmon-friendly channel that will be routed through large riparian buffers, creating a greatly improved habitat.

Similarly, many of the wetlands that will be affected exist on the edges of I-5 or in active farmland, providing relatively marginal habitat value. We're working with WSDOT to identify wetland mitigation sites that will allow for full restoration and also provide connectivity to Hylebos Creek.