Coalbank Slough Project Development

This Technical Assistance grant proposes to develop a multi-faceted habitat restoration project in the Coalbank Slough sub-basin, by monitoring/assessing/evaluating current watershed conditions and developing restoration treatments that will restore watershed function and improve water quality through fish passage, access to off-channel habitat, riparian planting/fencing and livestock exclusion fencing. The Coalbank Slough sub-basin is a DEQ 303(d) listed stream (bacteria and temperature) draining to the Coos Estuary. Situated along a narrow agricultural valley and directly adjacent to Coos Bay, this sub-basin has been heavily impacted by past land management practices, resulting in stream channelization, outdated/undersized infrastructure and removal of riparian trees/shrubs that have negatively impacted water quality and aquatic species for decades. This project proposes to evaluate restoration potential across ~8.3 miles of stream within the Coalbank Slough sub-basin having ~3.5 miles of high Coho Intrinsic Potential (range 0.8 - 1.0) and a large concentration of critical anchor habitats identified in the recent Coho SAP.

OWEB funds will cover project management, tidal monitoring, RTK elevation mapping, permit scoping, hydrologic review, project designs, travel, project materials, and indirect costs. Private lowland landowners and members of the Englewood Diking and Libby Drainage Districts have met with CoosWA and CCD Business Development Corporation staff and are supportive of this planning and design project. The Coos County Road Department, City of Coos Bay, ODFW and USACE have met with the districts to discuss implementation strategies. CoosWA has started conversations with NRCS, CREP and SWCD to expand on the ecological uplift and collaborative intent of this multi-faceted project. Tribal partners at CTCLUSI’s (Tribal Historical Preservation Office) are committed to assisting with preliminary site visits for archaeology evaluation of this project.

Restoration of this site will provide salmonids with valuable off-channel rearing habitat. The site is positioned adjacent to the coos estuary and provides a resting area for migrating salmonids on their way to the estuary and out to the ocean. The project is designed to create complex habitat through a network of tidal channels, which will allow fish to self-regulate along gradients of water velocity, salinity, and stream temperatures. The proposed restoration treatments will allow us to address the primary coho limiting factors (summer/winter rearing) within the Coalbank Slough sub-basin with the hope of increased juvenile survival/abundance and ultimately resulting in a more robust and healthier out migrating smolt population annually.