Tidal Wetland Prioritization for the Smith River Watershed, Umpqua River Estuary of Oregon

Throughout the Pacific Northwest, there is increasing recognition of estuarine contributions to watershed and marine processes. This recognition has generated new interest in tidal wetland conservation and restoration. In Oregon, overall losses of tidal wetlands since the 1850’s are estimated at 70% (Christy 2004, Good 2000, Boule and Bierly 1987, Thomas 1983), supporting the need for restoration. Conservation of the small remaining percentage of tidal wetlands is equally important. However, because each estuary offers a wide variety of restoration and conservation opportunities, strategic planning is needed.

This prioritization is designed to provide strategic focus for tidal wetland conservation and restoration actions undertaken in partnership with willing landowners. The study highlights land areas in the Smith River Watershed (within the Umpqua River estuary) where tidal wetland restoration or conservation action may offer the biggest ecological “bang for the buck” – that is, those locations that may offer the highest potential to protect or increase estuary functions. The information provided by this study provides a basis for working with interested landowners to develop site-specific action plans.

This study’s products are meant for active use. Information was stored in a Geographic Information System (GIS) and in Excel spreadsheets. The GIS shapefiles, spreadsheets and maps can be used to organize information about tidal wetlands and estuary conservation activities. The estuary is a dynamic place, so we recommend regular updating of site-specific data, as well as verification of the details in this report before site-specific action planning.

This prioritization uses ecological factors to rank sites for both conservation and restoration actions. The study uses an ecosystem perspective, prioritizing wetland areas (“sites”) rather than specific restoration projects. Criteria for prioritization included size of site, tidal channel condition, wetland connectivity, salmonid habitat connectivity, historic vegetation type, and diversity of current vegetation types. Information on these characteristics was obtained from publicly available data, field reconnaissance (offsite observation), and aerial photograph interpretation. Number of landowners, ownership type, proximity to development, and community perceptions can also be important factors in restoration planning. These factors are addressed in supplemental analyses.

This study has no regulatory intent or significance; it is intended only to foster conservation and restoration by interested and willing landowners. This project did not delineate jurisdictional wetlands; existing NWI maps were used for site boundaries. Because NWI maps are based on offsite data and establishment of wetland boundaries requires field work (beyond the scope of this project), this study’s sites may contain both wetlands and uplands. The results of this study do not alter the regulatory status of any resources, and the study is not intended to replace existing regulatory planning processes. For example, this study cannot substitute for regulatory resource evaluations such as determinations of significance in the context of comprehensive planning programs. This prioritization is not intended to be an assessment of site functions. Assessment of tidal wetland functions is a complex and technical field (Simenstad et al. 1991, Adamus 2005a, b, c) and not within the scope of this analysis. However, the criteria used for prioritization were selected because they strongly influence a broad range of tidal wetland functions.

This study strives for transparent methods and usability. The data sources, data manipulations, scoring methods, and results are thoroughly documented and all analyses are repeatable. All of the data used are stored in the site information tables and can be accessed, checked for accuracy, and updated as needed. Sufficient data are provided for fine-tuning site selection and action planning; these data (and additional new data) can also be used to re-rank sites using alternative methods if desired.

This prioritization is intended to provide a broad perspective and help guide decisions; it should not be used to eliminate any site from consideration for restoration or conservation. Even sites ranked low in this study are important, because so many tidal wetlands have been lost or converted to other habitat types. All tidal wetlands offer valuable ecological services to people and wildlife.

To improve the accuracy and usefulness of this study, we actively sought input from local landowners, residents and resource specialists. Information gleaned from landowner meetings and other forums has been included in the site characterization and prioritization, the site information table, and this written report.