Mapping Restored Tidal Connectivity in West Coast Estuaries

The Pacific Marine and Estuarine Fish Habitat Partnership (PMEP) has created a spatial data framework and web-based mapping tools that help restoration practitioners characterize habitats and synthesize information in support of habitat conservation and restoration goals. The tools provide easy access to compiled information on estuaries of California, Oregon, and Washington, including the Washington portion of the Salish Sea. The framework includes an indirect assessment of tidal wetland losses. PMEP identified a need to update the tidal wetland loss assessment to include areas where tidal connectivity and inundation have been restored. PMEP mapped 127 tidal re-connection projects across the West Coast, identifying 8,085 hectares (19,978 acres) of restored tidal wetland habitat. The project focused on mapping restored areas that were shown as “lost” within the 55 estuaries included in PMEP’s original tidal wetland loss assessment. Of the 55 estuaries assessed for tidal wetland loss, 13 were within the Salish Sea, and 7 of those had restored areas mapped as part of this effort. Restored areas that were already classified as tidal in the National Wetland Inventory were shown as “retained” in the tidal wetland loss assessment and were generally not included in this new mapping effort. The restored areas mapping effort resulted in 2.3% of tidal wetlands that were previously classified as “lost” being reclassified as “restored,” while 82.7% of tidal wetlands remained classified as “lost.” The Salish Sea region had the highest change in classification, with 4.1% of tidal wetlands that were lost now classified as restored. These results illustrate both the successes of restoring tidal connectivity and the potential for future efforts to re-connect important fish habitat across the West Coast