Oregon State University
OP-10: Biodiversity

The City of Corvallis maintains Natural Features Inventories throughout the Corvallis Urban Growth Boundary (UGB) for streams, wetlands, riparian areas, wildlife habitats, significant vegetation, and tree groves. These inventories are used in identifying specific Natural Hazards and Natural Resources in the Corvallis Urban Growth Boundary that are protected according to the Natural Features and Natural Hazards provisions of the Corvallis Land Development Code. https://www.corvallisoregon.gov/cd/page/planning-division Examples of all three Corvallis area natural resource designations - wetlands, riparian corridors and significant vegetation can be found protected on the OSU campus. Oak Creek, in particular, represents an expansive highly protected riparian corridor that OSU has worked to restore and protect. More information on protected riparian areas can be found at: https://www.corvallisoregon.gov/cd/page/riparian-corridors-and-wetlands-map Significant vegetation on OSU's campus is also protected and deemed highly significant. OSU protects these areas from development and development-related impacts. More information on highly protected significant vegetation can be found here: https://www.corvallisoregon.gov/cd/page/land-development-code

OSU and the City of Corvallis, both independently and together, have identified wetlands and wildlife areas on the OSU Corvallis campus. More information about City's identification process can be found below and at this link: https://www.corvallisoregon.gov/cd/page/natural-features How To Use This Inventory The Natural Features Inventory is divided into four resource types: wetlands, riparian areas, wildlife habitat and tree groves. Each resource has a technical report that describes the detailed methodology with summary tables and analysis. Detailed data sheets can be found for each resource site. The maps are divided into two categories: water-related resources (wetlands and riparian areas) and upland resources (wildlife habitat and tree groves). Each resource category has three types of maps with increasing detail. A summary map identifies the resource location within the Corvallis UGB. The locator maps are divided by study area (north, west-central, south) and provide a map index to the detailed map sheets, using 2002 aerial photos as their base. Inventory Methodology Specific methods are used for each of the natural features in this inventory. The inventory and assessment methods described in this report are based on the Natural Features Scoping Project Report (2002) prepared by the Corvallis Natural Features Technical Advisory Committee (NFT AC). The scoping report provides clear direction regarding what natural features to inventory further and provides the methodological foundation for determining how to inventory the natural features. The functional values of each natural resource area are evaluated using ranking/point systems to allow comparisons among all areas with the same type of resources. Detailed descriptions of the methods are found in each of the technical reports. Briefly: - Local Wetlands Inventory (L WI) - the L WI includes all wetlands at least 0.5 acres is size, either isolated or within riparian assessment areas or wildlife habitat assessment areas. The methods are determined by Oregon Division of State Lands (DSL) administrative rules. The L WI is unique in that it is the only resource in which "significance" of a local wetland is determined by state administrative rules. The Oregon Freshwater Assessment Methodology (OFW AM) is used to assess whether or not a wetland meets the criteria for a Local Significant Wetland (LSW). - Riparian Assessment - the riparian assessment is conducted within riparian assessment areas (RAA), which vary in width depending on stream type (perennial or intermittent) and the presence of locally significant wetlands and/or continuous riparian vegetation. The width of the RAA extends beyond the width of the riparian vegetation to identify potential offsite impacts. Each RAA is mapped with subareas or "subpolygons" that indicate different vegetative cover types (i.e. trees, shrubs, grasses, developed). The methodology is based on the Urban Riparian Inventory and Assessment Guide (URIAG) and a supplemental Riparian Corridor Survey to provide additional information on vegetation cover and stream conditions consistent with the NFTAC Scoping Report. - Wildlife Habitat Assessment (WHA) - the wildlife habitat assessment includes all areas of at least five acres with natural vegetation, except for areas within riparian assessment areas. The WHA inventories and assess six general categories of habitat features or conditions: water, food, cover, human disturbance, patch size and connectivity, and unique features. Vegetation subpolygons are defined within each WHA area based on vegetative cover types. Each vegetation subpolygon includes a description and characterization of the vegetation and identification of any rare, threatened or endangered species associations. - Tree Grove Assessment (TGA) - tree grove assessments are conducted for all areas with trees that are predominantly 25 feet or more in height with a continuous canopy cover of 0.5 acres or more. The TGA distinguishes between isolated tree groves (less than five acres in size) and vegetative subpolygons within WHA areas (greater than five acres), but does not include tree cover within developed areas or riparian assessment areas. The TGA evaluates tree groves for scenic, aesthetic, and other functional values. Aerial photo interpretation is used to identify potential resource sites, which are then confirmed by field surveys. The fieldwork is conducted on-site where access permission is granted. Where access is not obtained, off-site assessments are conducted using aerial photographs, existing data sources, and observation from public lands and adjacent rights-of-way. In many cases, resource boundaries overlap. For example, tree groves may be isolated or part of a wildlife habitat assessment area; or, a riparian corridor may be located within a wildlife habitat assessment area. Similarly, wetlands may be part of either a wildlife habitat assessment area or a riparian assessment area. The methodology ensures comprehensive coverage and consideration of multiple functional values for each type of resource (i.e. riparian areas serve as wildlife habitat), while avoiding "double counting" resources.

https://www.corvallisoregon.gov/cd/page/natural-features

OSU takes multiple steps to protect wildlife habitat and sensitive areas on institutionally-owned land. OSU and the City of Corvallis have identified over 626 acres of land that OSU now has deemed protected from development. These areas currently fall into three categories highly protected riparian areas/corridors, highly protected significant vegetation, and Conservation Reserve Enhancement Program-protected (CREP) land. Under the CREP, OSU's Dept. of Animal and Rangeland Sciences has restored and protected areas of Oak Creek that wind through livestock facilities. Supported by funding from the U.S. Department of Agriculture and the Oregon Watershed Enhancement Board, the project created wildlife habitat and riparian buffers along more than five miles of streams that include Oak Creek and its tributaries. OSU has done other work to restore runs of Oak Creek, an urban stream and riparian area that runs through the heart of the main campus and many of OSU's agricultural areas. This work includes annual (or more frequent) stream cleanup events, removal of historical debris including dams and concrete, planting native plants, improved shading of the creek, fencing off the creek from animal areas to prevent direct access and work on stormwater outfalls to prevent erosion and slow and clean water using bioswales and other methods. Periodically, Oak Creek and its surrounding riparian area is used for academic course work, service learning requirements and research.