Nolan Creek Culvert Project
You will see a number of references to “culvert repair and replacement” projects in the work that we do here at the Hoh River Trust. But, for many, it is not always immediately apparent why we spend so much time, effort and money to complete these projects. In our effort to increase fish passage and habitat restoration, removing or replacing undersized or obsolete culverts represents a great opportunity to return a stream to a more natural flow state.
The very process of creating roads, for commercial timber usage as well as recreational use, mandate the need for culverts to allow streams or seasonal water passage to keep from having to rebuild the roads year after year. Unfortunately as these culverts were installed little or no consideration was given to whether or not the stream was historic fish spawning areas or would have serious impact to habitat.
And in some cases poorly designed culverts pose a threat to prime spawning grounds even if they are not placed on historic spawning streams. Undersized culverts will eventually create a damming effect behind them, collecting wood debris and silt, sometimes forcing upstream flooding and the elimination of the historic stream channel. In a significant flow event these culverts can wash out, taking the road with it and then depositing many cubic yards of silt and soil into prime spawning habitat downstream. This siltation of stream beds greatly reduces the likelihood of successful spawning.
Nolan Creek is a historic salmon spawning tributary to the Hoh River. In 2007 we got the approval and funding to replace a culvert on a Nolan Creek tributary that had cut-off access to upstream habitat. As you can see by the picture there was absolutely no way fish could pass beyond this culvert to reach several miles of fine juvenile habitat. Upstream of the culvert the historic channel was barely visible and became more like a marsh than a stream.
Smolt trapping below the culvert found some evidence of the presence of Coho and Chinook salmon as well as other native species. Trapping above the culvert, as was expected, found no evidence of salmon smolt. It is in these small streams with sufficient protective structure that salmon smolt find protection from predation and from being swept out by high water flows.
In September of 2007 the Hoh River Trust received funding through the Family Forest Fish Passage Program
of the Salmon Recovery Funding Board to remove the culvert and replace it with a concrete span bridge. The work was completed by Quigg Brothers, Inc. of Hoquiam and the project received a lot of local support and interest. As you can see in the picture, with the culvert removed Nolan Creek looks like a creek once again. Not all culvert projects are complete removal projects; many simply replace old, undersized culverts with culverts that insure fish passage.
Springtime in the Hoh River valley means runoff season. We can see flows in the mainstem of the Hoh River go from 600 cubic feet per second (CFS) to 60,000 CFS. As you can imagine this much water can quickly and radically change a landscape. We will be watching carefully as increased flows move through the reclaimed area. We expect to see habitat above the old culvert return to looking like a creek and hopefully, as fish return to the system we will see evidence of spawning activity and the presence of salmon smolt in this newly reclaimed habitat.