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Session A1- The Vermont culvert screening tools for aquatic organism passage and geomorphic compatibility

The Vermont Department of Environmental Conservation (DEC), Vermont Fish and Wildlife Department (FWD), and others have collected stream crossing structure data using the Bridge and Culvert Assessment in the Vermont Stream Geomorphic Assessment Protocols. A publicly accessible database currently contains information on 5,000 culverts. FWD uses information to identify structures that impact fish passage. DEC uses these data to evaluate culverts that increase flood and erosion risks. Towns can use this information to manage crossing structures. The AOP Coarse Screen characterizes passage by physical measures of the culvert and stream. These data are useful at the watershed and subwatershed scales to identify structures having the most impact. The AOP Retrofit Potential Screen identifies the likelihood of improving passage via structural culvert changes. this screening tool considers the biology of fish, and indicates the potential passability for strong, moderate, and weak swimmers. It is useful at the subwatershed and local catchment scales to target structures for further analysis and management. The AOP Habitat Connectivity Potential Screen indicates the habitat that would be reconnected if passage were improved. This screen is best applied at the subwatershed and local catchment scales to realize the potential gains in habitat due to changes at a structure or set of structures. The Vermont Culvert Geomorphic Compatibility Screening Tool is based on the disruption of natural sediment transport, hydrology, and channel form. Five variables (i.e., percent bank, full width, sediment and debris continuity, slope, approach angle, and bank erosion) generated from field data are used to represent the level of geomorphic compatibility between the structure and stream. When used together, the Vermont Culvert AOP Screening Tool and Geomorphic Compatibility Screening Tool offer a comprehensive view of how a culvert influences both the physical and biological aspects of a stream.