Estuary Restoration USFWS/Refuge partnership with NIT and DU (USGS?) Du – Engineering, grant management / NIT-technical support and funding assistance
Preferred alternative as implemented. 760 acres of estuary restored to tides. 250 acres of FW wetland habitat protected by setback levee, enhanced FW habitats with smaller levees/WCS and borrow areas. 25+ acres of new tidal riparian forest, reconnection of 8 significant tidal slough systems, ELJ to protect dike jct, Rock armor removal to allow river to migrate. Increased sanctuary areas. Improved FW wetlands in smaller area. New trail and boardwalk. Also NIT projects on E side of river – Pilot, Phase I, Phase II and Riparian Planting.
Clearing vegetation to facilitate earth work in spring 2009. Nesting bird surveys avoidance and deterrent implemented as well as reuse of woody mulch in riparian area.
Stage I dike removal – removing the top of the dike.
Stage II dike removal – Removal of 80% of the material while leaving a temporary wedge intact to keep out puget sound until lower than average high tides in September. Most material placed into borrow ditch where it came from originally.
Final berm removed in late Sept 2009 allowing tides to flood the site. Working around the tides and reconnecting channels as they moved around.
Rock armor removal to allow river to migrate and form distributary channels. Significant armor placed in mid 1970s due to dike breach and 1996/2002 after flood damage.
Barrier to fish, salinity, nutrient exchange, seeds. Subsidence due to farming drainage/tillage and loss of sediment from puget sound/river- Lots of new mudflats, Lots of sediment built up out side old dike.
Reconnected channels, no longer a barrier to water, fish, nutrients, sediments.
Channel reconnection – sediment accumulated outside the dike. Used clearing debris to access mudflats
Durring last phase of dike removal. Crews chased outgoing tides and incoming tide allowed to wash away last wedge to allow for full tidal cycle before evacuation to maximize dilution minimize water quality impacts.
Before/after photo of channel reconnection
Riparian habitats/ tidal influenced forest – important for out migrating salmon and nesting songbirds.
Mulch used to improve woody plant establishment. Very highest tides of the year inundate, but freshwater lens from river keeps very fresh. Pilot distributary channel to increase mixing zone fresh water input to site at high tide.
Pilot planting in riparian area. 500 local school children planted over 3000 willow cuttings. Additional planting planned for this winter over 20 acres. snags installed for raptor perches with logs cleared during the spring.
ELJ to protect Jct of new/old dike more habitat friendly bank protection in lieu of large rock wall
Challenging construction on tidal zone, 60’ pilings, racked logs 20’ below ground surface, salvage rip rap ballast to prevent undermining. Windfall logs donated by Ft. Lewis Forestry.
Willow rootwads installed for quick erosion control and heavy willow staking. Pilot structure meant to accumulate wood in the future and become more natural over time.
After construction, high tide inundates are with brackish river water.
Removal of culvert missed during construction in 2009. With hand crew and removal by boat
Boardwalk 5500 feet to replace trail along old dike. partial seasonal closure for waterfowl hunting.
AARA funding 2.7 million – Five Rivers Construction out of Longview. Employing 10 carpenters for 6 months. Many had not worked in months. Pin foundations in lieu of pile driving
Nisqually Delta Restoration Update
Nisqually NWR Estuary Restoration Update Nisqually River Council – November 19, 2010 Restoration Biologist Jesse Barham Key Partners