DESCRIPTION
The status of Lilliwaup Creek's habitat limits the spawning and rearing success of ESA-listed summer chum (threatened) and other anadromous species. Stream flow, tidal influence, estuarine connectivity, and spawning range are impaired by gravel aggradation in the 0.7 mile anadromous reach. Lack of riparian vegetation contributes to channel instability, reduces contribution of large woody debris, and reduces the amount of shade cover to cool the water and provide fish protection. Unmaintained culverts prevent access to side streams and pools. Upstream of the anadromous reach, steep stream banks may be unstable, threatening to repeat the mass wasting event that brought thousands of yards of gravel downstream into the reach in 2007.
The proposed project takes the first step toward restoring and protecting the anadromous reach by creating a Preliminary Project Design that identifies sites, methods, and alternatives for restoring: mainstem flows and side-stream connectivity (e.g. aggregated gravel and culvert removal); riparian and in-stream habitat (e.g. re-vegetation, install large woody debris); and the natural tidal influence. Upstream banks will also be assessed and stabilization alternatives proposed. Local residents are concerned about the creek's condition and express interest in seeing it restored. Over 16 years and several hundred thousand dollars in supplementation efforts to recover the Lilliwaup summer chum population are at risk if these issues are not addressed.
The Lilliwaup Creek Restoration Assessment and Preliminary Design report took the first steps toward restoring and protecting the anadromous reach. The Watershed Assessment section of the report found the following:
· A large reduction in the extent of tidal inundation experienced by the anadromous reach of Lilliwaup Creek, relative to the creek’s recent (5-10 year) and earliest recorded (1884 T-Sheet) structure;
· Extensive clear cutting to the forests below Lilliwaup Swamp during the last 70 years;
· The deposition of approximately 60,000 cubic yards of coarse sediment in anadromous reach of Lilliwaup Creek since 1995, including more than 45,000 cubic yards of coarse sediment between 2005 and 2007;
· During summer low flows up to 23% of the water in Lilliwaup Creek Flows subsurface and is therefore unavailable to ESA listed (threatened) Lilliwaup Creek summer chum present in the creek at that time;
· Channel complexity has been reduced as some channels have been shoaled and widened by aggraded sediment, and not all remaining channels maintain flow in late summer creating a much greater stranding risk for ESA listed (threatened) Lilliwaup Creek summer chum;
· Less frequent pools (58% of the target frequency) that are shallower than previously existing pools (given the shoaling and widening of the main channel, and the burial of previously existing large woody debris and other habitat forming structures) likely represents a decrease in function and smaller area of “tail out” habitat which spawning summer chum salmon prefer; and
· Riparian habitat adjacent to the lower anadromous reach has been significantly degraded by sediment deposition on the stream banks, and sediment aggradation in the main channel.
The Preliminary Project Design section of the report contained the following elements:
1. Upland slope and sediment source stabilization: stabilizing Winter Creek (a seasonally active sub-basin of Lilliwaup Creek); stabilizing and revegetating the flume slide scar, the road fill culvert failure in Beardsley Creek, and the logging landing slide scar in Beardsley Creek.
2. Off channel restoration: deepening the existing ponds to the south of the hatchery and connecting them to the eastern channel of Lilliwaup Creek at a point several hundred feet downstream of the east west channel fork; and constructing a small bridge to allow fish passage below an existing private road.
3. Creek channel restoration: removing sediment from the main channel, eastern and western forks to restore pre-2005 bed elevations and gradients which will restore tidal inundation, tidal prism, and reduce groundwater level in riparian soils; establishing channel dimensions necessary to maintain sediment transport, channel integrity, bank stability, and restore late summer surface flows in Lilliwaup Creek, and year round connectivity to the newly restored off channel habitat sites.
4. Upland enhancement: placing the majority of the sediment taken from the creek channel and placing it along the banks to be accessed and mobilized gradually; and placing the rich organic material generated by restoring the off channel habitat on top of the coarse sediment to improve fertility of upland soils and facilitate more diverse and abundant native vegetation and conifer growth.
5. Riparian vegetation and large woody debris enhancement: placing large woody debris suitable to bring abundance and volume up to target levels; and planting diverse native riparian vegetation which will include a mix of conifers and deciduous trees, shrubs, and groundcover to jumpstart the current state of succession.
In addition, comments on the report were solicited and incorporated as the project transitioned to the next phase (“Lilliwaup Creek 100% Design Completion”, PRISM #11-1316). Comments regarding the report are contained in Appendix K of the Lilliwaup Creek Watershed Assessment and Preliminary Design Report, and the comments are addressed in the report’s Executive Summary section.
Failing to restore and protect the anadromous reach of Lilliwaup Creek will squander not only biological resource of ESA listed (threatened) Hood Canal summer chum, but also: the good will of the local residents who continue to be concerned about the creek’s condition and have expressed interest in participating in activities to restore and maintain it; and over 16 years and several hundred thousand dollars in supplementation efforts already spent to recover Hood Canal summer chum in Lilliwaup Creek.
The condition of Lilliwaup Creek’s habitat continues to limit the spawning and rearing success of ESA-listed summer chum (threatened) and other native species. Stream flow, tidal influence, estuarine connectivity, and spawning range are impaired by gravel aggradation in the 0.7 mile anadromous reach. Lack of riparian vegetation contributes to channel instability, reduces contribution of large woody debris, and reduces the amount of shade cover to cool the water and provide cover to returning adults and out-migrating smolts. Unmaintained culverts prevent access to side streams and pools. Upstream of the anadromous reach, slide scars are revegetating slowly.