Jefferson County Public Works has received funding from FEMA’s Hazard Mitigation Grant Program to replace the Snow Creek Road, milepost 0.84, culvert. The current culvert was constructed in 1968 where the road crosses a 30-45 foot deep canyon/stream. The bottom of the 24-inch diameter, 190 ft long, corrugated metal pipe has rusted through undermining the culvert outlet and causing segments to drop off. The culvert was also originally installed under poorly compacted and steeply sloping fill material. It is undersized and has repeatedly become blocked with debris during storm events causing a dam that threatens to wash out the road fill. Past flood events have required the road crew to “tend” the culvert for hours using inlet poles and grapples to unplug it and keep it flowing. If the pipe were to plug and cause water to crest over the top of the road, it is likely the road fill would collapse sending a torrent of 14,000 cubic yards of liquefied “mud” down the stream and hillside into Lake Leland.
The culvert will be replaced with a new 72-inch diameter culvert with a 75-year design life. The greatly increased diameter will easily handle the necessary water and debris passage, eliminating the threat of washout, and allowing for the future relining of the pipe at a significantly reduced cost.
The current project is estimated to cost approximately $1.5 million, with $1.16 million secured in grant funding, and $500,000 secured through a Washington State Public Works Board construction loan. This project is scheduled to got to construction in summer of 2023.