Oregon South Coast Estuaries: Hunter Creek, Pistol River, Chetco River, & Winchuck River Tidal Wetlands Assessment (2012-2015)

Identification Information

Citation

Originator: Cindy Ricks Myers, Curry Watersheds Partnership

Publish Date: 9/30/2015

Online Link: None

BPA Project #:

Contact Information

Agency: Watershed Councils

Name: Cindy Myers

Job Position: Water Quality Monitoring Program Coordinator

Telephone: 541-425-0239

E-Mail Address: cricks@currywatersheds.org

Description

Abstract: Although tidal wetlands on the Oregon South Coast are limited in extent, they may be particularly valuable for a variety of wetland functions. This assessment combines the Brophy (2007) and Adamus (2005) approaches to quantify the extent and causes of habitat loss and hydrogeomorphic changes in tidal wetlands of four Oregon South Coast Estuaries. The potential for restoring critical habitat and wetland functions is ranked using Ecological Prioritization Criteria (Brophy, 2007), while indicators of function, risk, and integrity are evaluated using scoring models from the Adamus (2005) Hydrogeomorphic (HGM) Rapid Assessment Method. The extent of inundation (head of tide) during King Tide conditions was observed and documented by staff and volunteers. Field measurements of salinity concentrations and stratification during high and low flow were tabulated. The historic aerial photo record was examined to detect channel migration, floodplain re-vegetation, and human-caused alterations. Related studies were combined with these observations to provide a summary of estuary hydrology, sedimentation, and channel stability related to wetland establishment and loss in each of the four estuaries. Ecological priority scores (Brophy, 2007) varied with wetland size, tidal channel condition, connectivity, and diversity of vegetation classes. Wetlands were categorized as restoration or conservation types, and priority ranks for wetlands were depicted on orthophoto base maps. Tidal wetlands and nearby floodplain wetlands in a variety of geomorphic settings were surveyed using the HGM protocol, including one “reference” and one restoration site . The HGM survey scores 55 indicators, including botanical transects, used to rank wetland functions (calculated by indicator scoring models). Risks to wetlands include human disturbances in close proximity to the wetlands and floodplains, resulting from the narrow valley floors in this tectonically active region. Wetland integrity is threatened by a surprising large proportion of non-native species in the botanical transects, 40%. Wetland indicators that scored low, and could be restored or enhanced, are discussed in a restoration considerations narrative. Wetland descriptions include lists of plant species, grouped by wetland status, native/non-native, and perennial/annual persistence. In addition to the HGM scores, an analysis of cover and diversity of all plant species in plots, off-transect species diversity, and waterfowl food distribution was completed using a wetland vegetation database developed for the Oregon South Coast.

Purpose: The surveys were undertaken to inform strategic planning for conservation and restoration of tidal wetlands, including mitigation of risks, maintenance of wetland integrity, and recommendations for actions to improve wetland functions. It is expected that the surveys will provide baseline data, and functional assessments needed for permitting of future wetland restoration activities.

Time Period of Content: Tidal inundation 2012-2015, Field survey summer 2013

Geographic Extent: South Coast Basin, Chetco Sub-basin, Estuaries and Tidal Wetlands

Status: Draft

Use Constraints: Analyses of South Coast Basin, Sixes Sub-basin, Estuaries and Tidal Wetlands, surveyed in 2014, are ongoing. Combined report to be released 12/15/15.

Format: Document (.pdf); containing maps and tables from spreadsheets and databases.

Data Quality Information

Lineage-Source: Original data generated from field observations, historic aerial photo overlays, botanical transects, and surveys of HGM indictors.

Data Information

No data information was supplied.

Entity and Attribute Information

Attributes Description: Ecological Prioritization Criteria from OWEB Estuary Component of Watershed Assessment Manual (Brophy 2007) and 55 Indicators from Hydrogeomorphic Rapid Assessment Methods (Adamus 2005).

Is a physical copy maintained for reference at Headquarters? Unknown