Wetland restoration after a mega-storm Jyneen Thatcher, Wetland Scientist Washington Conservation District Paul Bockenstedt, Ecologist Stantec

Prior conditions South Twin Lake- an impaired waters Brown’s Creek – a designated trout stream Wetland delineation

Approved development

Site conditions

Rainfall

August 14, 2007 Sediment and mulch against silt fence

August 14, 2007 Brown’s Creek Sediment plume

Site observations

Pond Brown’s Creek Slope Floodplain Old excavation (1980s) Old blow-out to Creek (1990s) Sediment flow

My observations

Problem list - wetlands Sediment fill into seepage wetlands and upland buffer Sediment into floodplain wetland and excavation Old blow-out into stream Hierarchy of impacts across the site Design of restoration order Buried bottle gentian in seepage area

Planning the restoration Timing of restoration What/how to restore Impact on private land Coordination with other agencies (DNR, BCWD, PCA) Responsive developer

First steps Stabilize site against more damage Stabilize outlet to Creek Develop restoration plan –Hire ecologist

Next steps Better stabilization of pond outlet Discuss options with ecologists

Restoration plan development Summarized conditions Identified areas for restoration –Areas with sediment –Surrounding invasive, nonnative areas –Outlet design for previously drained wetland Identify locations for monitoring Outline implementation specific to each sedimentation area

Restoration implementation Initial Restoration –Supplemental native seeding with diverse, local ecotype seed mix 45 spp. forbs, 5 spp. graminoids –Cut/treat invasive, nonnative vegetation

Restoration implementation Initial Restoration of Stone wetland –Reconstruct outlet of previously drained wetland –Sediment removal –Native seeding of disturbed areas with BWSR mix Grow-in maintenance –Spot spray, spot mow, hand weed

Monitoring Initial data collection at monitoring points in fall 2007 Annual monitoring –Data collected at five locations Within sedimentation areas In wetland with reconstructed outlet

Monitoring Results after 4 years –Buried seepage wetlands exhibit overall diminished quality Loss of some desirable natives in areas with ~4-6+ inches of sediment (i.e. bottle gentian) –Some desirable native species stable, post-sedimentation –Rebound of nonnatives and invasive natives in some areas Bottle gentian and foxglove beardtongue in buried seepage area

Monitoring Results after 4 years –Overall reduction of invasive, nonnative cover –Good establishment of seeded native grasses and forbs 20+ spp. established 35-45% cover (A1 - C1) –Vegetation management along Brown’s Creek contributes to long- term improvement Area cleared of dense buckthorn/honeysuckle and seeded to natives (top 2009, bottom 2010)

Site A-1 September 2008

Site B-1 September 2008

Site A-1July 2010

Site B-1 July 2010

Monitoring Results after 4 years –Restoration of pond is success, with good diversity of vegetation and stabilized outlet

What went right Spirit of cooperation, trust and mutual respect among agency and private sector staff involved Reasonable proposals for timing Cooperative developer/landowner Agreement with private landowner Support by other agencies for this process

Wetland restoration after a mega-storm Jyneen Thatcher, Wetland Scientist Washington Conservation District ext.37 Paul Bockenstedt, Ecologist Thank you!Questions?