To achieve a goal of “no net loss” of wetland functions as well as acreage, it is important to know which functions wetlands in a specific region or watershed may individually provide, at what level. Although methods exist for assessing functions of Oregon wetlands (ORWAP; Adamus et al. 2009), site visits and hours of data collection are required to apply these to any wetland. Moreover, property access restrictions prohibit their use on many wetlands. Thus, when there is a comprehensive objective to assess all mapped wetlands in a region or watershed, time and manpower constraints require that spatial data be processed automatically using GIS, even though assessments of functions using such an approach have much lower levels of certainty. The primary object of this project was to define criteria that would allow only the use of existing spatial databases (and only those with comprehensive coverage of the ecoregion) to identify the HGM class of mapped Willamette Ecoregion wetlands, and then apply those criteria automatically and systematically to every mapped wetland in the ecoregion, resulting in an HGM label for each mapped wetland. An ancillary goal was the creation of a database that describes over 200 attributes of each mapped wetland in the Willamette ecoregion, i.e., a regional wetland “profile.”

1.0 Background and Objectives 2.0 Methods 2.1 Data Sources 2.2 Defining Wetland Polygon Boundaries 2.3 Extracting Attributes from Spatial Data 2.4 Criteria for Predicting Hydrogeomorphic (HGM) Class from Existing Spatial Data, and Results 3.0 Validation of HGM Class Assignments 3.1 Validation Process 3.2 Validation Results 3.3 The Final (Reclassified) Database 4.0 Limitations 5.0 Willamette Wetlands Geodatabase 6.0 Literature Cited 6.0 Electronic Appendices File 1. Wetlands Geodatabase and Data Dictionary for the Willamette Ecoregion File 2. Wetlands Layer with HGM Labels (shapefiles in Arc format) Tables: Table 1. Statistical summary of the validation Table 2. Detailed validation results for assigned HGM classes.