Hoh Springs Stream Enhancement & Fish Passage Project

The Hoh Springs project removed man-made obstacles to coho and steelhead migration within a spring fed stream system. The project entailed the removal of two decommissioned weirs. An upper weir was plugged, buried and bypassed with a 230-ft. LWD- roughened channel. The lower weir, made of steel and concrete, was removed along with the blocking sediment. Approximate current pool elevation was be maintained by use of channel roughening LWD, gravel bars and boulders. The existing straightened stream channel was meandered to increase length and reduce gradient. Project also involved the placement of spawning gravel in the restored channel.

Due to the reduced costs to implement the project at the Hoh Springs worksite the Tribe also implemented a project at Dismal Pond located on the Hoh River where two impassable fish barriers were were removed to promote connectivity to off channel wetland complexes.

Added detail (9-13-16) to respond to NOAA comments:
Hoh Springs:
The work that occurred at the Hoh Springs worksite was intended to primarily provide access to wetland complex habitat in Hoh Springs a tributary to Dismal Creek. The project involved decommissioning two defunct man made WDFW SSHEAR structures (initially described as weirs) that were intended to increase forested wetland habitat by impounding water to increase wetland capacity. These structures when designed were intended to allow fish passage. Over time the lack of maintenance of the facilities resulted in them becoming impassable barriers. This project removed the two structures but rerouting the flow and creating a meander to provide a gradient that would maintain the existing wetland elevation and restore anadromous access to the forested wetland habitat.
Dismal Pond:
Dismal Pond formed from excavation associated with gravel pit operation. It is directly adjacent to a side channel of the Hoh mainstem. Once gravel operations ceased a straight channel was excavated to allow connectivity to the Hoh River. Over time the gradient of the channel flattened due aggradation which result in minimal interaction with the river and created a passage barrier. This project widened the original channel and increased the outlet gradient to provide access to dismal pond and promote better flushing of the pond to improve water quality parameters for salmonids. A Dismal pond inlet also had a natural barrier (beaver dam) that prevented access to additional wetland habitat. This obstruction was removed and a replaced with a meander channel to provide access to the wetland habitat previously not available due to the beaver dam.

This project site is located on property owned by Hoh River Trust, a conservancy group that manages their riparian forestland to establish old growth characteristics and to provide habitat for listed species and unlisted native salmonid populations. Two small weirs were built in the early 1990’s by the Washington Dept of Fisheries (SSHEAR projects) to increase pool area and juvenile rearing habitat in this high quality tributary to the Hoh River. Pool habitat is a recognized limiting factor for salmonid production in the Hoh basin. Both weirs were decommissioned.

The project will eliminate need for daily or weekly maintenance during periods when juvenile coho and steelhead migrate in and out of the spring fed ponds. Since these periods often coincide with storm events when maintenance is delayed or not possible, improved fry and smolt utilization should occur. Species with different run timing (such as chinook and cutthroat) will also have improved access. The silt layer that has built up on pre-existing spawning habitat will flush out as LWD and channel constrictions increase current velocity. Beaver usage will continue but is not expected to create permanent blockages to juvenile or adult passage.