Howard Lake Road Removal & Upper Klickitat Floodplain Restoration

he history of impacts to the Klickitat River in the project area and its contributing watershed include direct manipulation to the channel and floodplain in the form of the BIA 32 Road crossing and the 255 Road crossing not far downstream, increased density of road networks in the contributing watershed (particularly in the Diamond Fork watershed), and timber harvest and cattle grazing in the contributing watershed. The current site conditions have limited salmonid productivity due to the lack of habitat diversity: the mainstem is primarily a plane-bed riffle with coarsened substrate; pools for juvenile rearing are few; access to floodplain habitats is limited to times of spring run-off, and sheet flow on the floodplain is routed back to the river due to the cross-valley embankment; and hydraulic conditions in the reach are severe due to flow largely being constrained in the east channel.



The Project design specifically addresses the primary limiting factors for this reach. These include lack of pools for juvenile rearing, restricted access to floodplain habitats, and increased peak-flow velocities in the main channel (due to channelization). The Project proposes full removal of artificial barriers to floodplain connectivity, improvement of in-channel rearing habitat, and increased access to enhanced off-channel habitat.



The removal of the valley-crossing of the BIA 32 Road and both bridges is expected to naturalize physical processes at the valley scale in two main ways. First, higher in-stream flows, such as ordinary high water and bankfull flow, interact with bridge geometry in the main channel. Secondly, overbank flows routed through floodplain channels are bisected by the road embankment. Placement of large wood structures in the main channel (east channel) and high flow channels (west channel and other high flow channels) is intended to enhance in-channel habitat, enhance off-channel habitat, increase access to off-channel habitat, and increase floodplain connectivity. Excavation of floodplain side-channel inlets is expected to increase the frequency and duration of side-channel connectivity with main channel flow. The overall effect is expected to be a perennial, multi-thread channel system.



These changes are expected to benefit target species at multiple life-stages including spawning and juvenile phases. Changes to in-channel hydraulics are expected to decrease velocity and sort gravel, benefiting spawning, adult holding, and juvenile rearing. Increase in access to, and enhancement of, off-channel habitat is expected to primarily benefit juvenile rearing and migration. Increased floodplain connectivity, particularly through the removal of the BIA 32 Road, is expected to provide overall benefits to process domains leading to natural formation and sustainability of critical habitats. Project goals and objectives are described in more detail in the attached proposal document.



Worksite #1 Proposed Work:



The cross-valley road alignment and associated fill will be removed along with two existing concrete bridges (note that this was reported under metric C.4.c as levee removal/alteration(. Strategic placement of wood will be utilized to reconfigure 0.75 miles of mainstem Klickitat River channel and 0.75 miles of side channel habitat. Twelve pools will be created through the placement of 30 log structures. Nearly 40 acres of floodplain will be reconnected. Funds will be used for a construction contract to remove the historic road and fill, harvest and transport wood to the project site and the construction of logjams on the mainsteam and side channels to encourage a multi-thread channel platform.

In the Klickitat Lead Entity Salmon Recovery Strategy (2021, Priority Matrix, pg. 75), the project location is in a Tier B reach: Upper Klickitat Mainstem: McGreedy Creek to Diamond Fork. The rationale for this ranking is that the reach has a high potential for productivity if restored.



The limiting factors identified are: lack of pools to support rearing of juveniles. Restriction of access to floodplain habitats. High Peak flow velocity.



The habitat forming processes are: Confinement of the channel by the road increases peak flow velocities. LWD, which contributes to pool formation, is lacking due to road construction and stream cleaning. The confinement limits accumulation of wood in the channel.

The A priority action to address these limiting factors are: Place ballasted LWD to increase rearing habitat. Realign channel in areas where benefits can be reasonably attained. The rational for these proposed actions is: There are larges sections of stream that are simplified with little pool volume. Placement of wood will increase rearing habitat through the formation of pools, improvement of sediment sorting and improvement of habitat complexity. Perforation of the road where realignment is impractical will allow peak flows to be reduced by allowing waters to move onto the floodplain.



The project is expected to benefit target species at multiple life-stages including spawning and juvenile phases. Changes to in-channel hydraulics are expected to decrease velocity and sort gravel, benefiting spawning, adult holding, and juvenile rearing. Increase in access to, and enhancement of, off-channel habitat is expected to primarily benefit juvenile rearing and migration. Increased floodplain connectivity, particularly through the removal of the BIA 32 Road, is expected to provide overall benefits to process domains leading to natural formation and sustainability of critical habitats.