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University of Oregon North Campus Conditional Use Permit Project Riparian Assessment and Management Report fringe wetlands, boulder clusters, and backwater and side channel habitat. These components along the Willamette River provide habitat and forage for a wide-range of native fish species, both resident and anadromous. In order to spawn, most native fish require spawning gravels of various sizes with adequate flow and cool clear water. In addition, rearing juveniles and adults need sufficient cover in the form of large woody debris, undercut banks, and backwater or side channel habitat to provide protection from predators and refuge during high flow events. Based on the aquatic habitat features present along the Willamette River, the aquatic habitat within in the PSA appears to provide habitat that is suitable for all native fish species life stages expected to occur in the river. Many other aquatic and water-dependent terrestrial species can benefit from these aquatic habitat components. For example, vegetated benches provide excellent habitat for garter snakes (Thamnophis sp.). Backwater microhabitats, fringe wetlands, and large woody debris create habitat for turtles to bask, reproduce, migrate, and forage. Waterfowl utilize fringe wetlands and gravel bars for feeding and roosting as well as shelters from disturbance. Sensitive species such as bald eagles and osprey rely on these aquatic habitats for forage. River- dependent mammals such as beavers and otters, along with several species of bat, all rely on one or more of the river components listed above for food and shelter. Although the Willamette River within the PSA provides habitat for aquatic species, the area has also been subject to anthropogenic disturbances for many years. Current and historic use of the area for recreation has also directly and indirectly affected local aquatic habitat through disturbances to vegetation and streambank morphology, refuse build up, and nonpoint source pollutants. The majority of the PSA adjacent to the aquatic habitat was used as a gravel plant, a concrete plant, a transmission pole yard, and a sand and gravel mine. These historical industrial land uses have contributed to degraded aquatic conditions due to the runoff of contaminants and the addition of artificial barriers at the bottom of the bank. During the July 2017 field effort, MB&G noted riprap as well as large blocks of concrete slabs along the streambanks in the PSA. These slabs were most likely excess material from the concrete plant and were likely used to stabilize the bank. While these concrete slabs can provide limited shade and shelter to some aquatic species, the unnatural shape and size likely deter native species. Riprap and concrete blocks along a streambank can affect local flow hydraulics and scour regimes resulting in degraded channel and streambank dynamics. In addition, large riprap and concrete pieces can transfer heat to waterbodies as they absorb solar radiation during long summer days. However, the majority of substrate materials along the river margin consisted of cobbles, cohesive silt, and clay and are relatively resistant to erosion. 3.2Riparian Habitat Historically, the PSA was completely comprised of riparian bottomland forest with a wide floodplain and sloped bankline (Johnson et. al., 2010). Land uses have dramatically reduced the historic extent of the PSA’s riparian forest to a narrow band of habitat along the Willamette River and Millrace Slough. Thick patches of Himalayan blackberry grow adjacent to and within the riparian zone, degrading habitat function and composition. Streambank armoring and other local physical streambank alterations have affected the riparian zone’s ability to adapt and respond naturally to various flow regimes in the river. Flood control measures upstream of the PSA at multiple large reservoirs have limited the frequency and intensity of flood events, which limits the natural development and maintenance of riparian habitat and floodplain connectivity. Still, this narrow band of riparian habitat provides many of the necessary functions that are beneficial to the adjacent floodplain and aquatic areas, such as channel stability, limited flood storage, primary production and nutrient cycling, and shade. It also provides habitat for terrestrial wildlife species. page 5