Issue

The Washington Department of Ecology required up-to-date land cover information and more accurate wetland maps to explore trends in wetland loss and find strategies to avoid future losses. Producing and developing land cover data is expensive and requires technical expertise and time that many agencies don’t always have.

Process

Two programs—the Washington Department of Ecology and NOAA Coastal Change Analysis Program (C-CAP)—worked together on their shared goals of updating regional land cover data and improving wetland mapping accuracy. The team was able to expedite the C-CAP 2010 land cover update and develop a longer period of trend analysis with historic 1992 data from the coastal portion of Washington State.

The partners worked to improve wetland mapping accuracy for the state. They also used a new method for modeling potential wetlands by combined several data layers, including the National Wetland Inventory, Soil Survey Geographic (SSURGO) data, National Hydrography Dataset, C-CAP, National Elevation Dataset, and Landsat Satellite imagery and modeling. This approach provided a more robust representation of potential wetland features than any single data set could provide alone and addressed areas with gaps in coverage or dates.

Impact

Because of this partnership, the Washington Department of Ecology was able to obtain 2010 regional land cover data quickly, 1992 data at a lower cost, and wetland maps that were more accurate. The wetland potential product may be useful for wetland mitigation, restoration site evaluation, and assessing areas as past or current wetlands. The wetland potential methods were later applied to the entire C-CAP national mapping area and used to improve the wetlands categories mapped within all the regional land cover products produced by NOAA.