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Koll North Creek - Monitoring Report (1994)IES ASSOCIATES . `.? Th 1 Compagy K North _C;.ge 2 18 - ',c20th"A nu Hot 11, ,WAcP' 8021 June 6, 1995 Business Center S.E., Suite 138 ME.A4 Orhead ?I?q A 98502 JUN ' Ph: (206) 43-0127 CH I '-- c:,. ; nLLL COM. DEV. T994 Monitoring Report - Koll-North Creek By-Pass Channel Wetlands Introduction Three site investigations were complete during 1994, to monitor the over-flow channel wetland. The survey was a continuation of the 1993 monitoring report, which was continued into the spring of 1994, in an effort to evaluate the survival and spread of willows in the back-water, by-pass channel area. The site was walked and photographed from the surrounding area. The interior of the area was mapped to document the extent of the willow invasion, open-water components, island and other wetland species. Wildlife data was collected in each of the three site visits to record nesting activity (during the summer of 1994), fall migration figures and wintering data, through December 31. Wildlife data is a compilation of IES Associates field data and data from resident observers (who have maintained bird lists for the past 5 years). Vegetation The dramatic increase and spread of Sitka willow (Salix sitchensis), that was observed in 1993, continued into 1994. The extent of willow has not changed significantly; however, there are scattered patches of willow further south, within the bounds of the overflow wetland. The willow trees continued to grow, with some plants reaching 4.5 to 5 feet. However, the majority of plants remained approximately 3-3.5 feet tall. The willows have formed a matted root structure, which has eliminated the ability to pull the willow for thinning or use as nursery stock. Certain plants are starting to become more de winant . June 6, 1995 The Koll Company RE: 1994 Monitoring Report - Koll North Creek By-Pass channel Wetlands In portions of the area, the willow stand has become a mono- culture, with no vegetative ground cover. In other areas, buttercup and patches of reed canarygrass are still present; however, the willow has successfully "out-competed" reed canarygrass, isolating it to small clumps or individual stems. The north end of the mitigation wetland is still dominated by reed canarygrass, with scattered soft rush. In this area, the black cottonwood and river willow are being stressed by the competition for nutrients. There is a low area, along the east side that parallels the berm separation (between North Creek and the emergent marsh area), that has standing water and reed canarygrass throughout. South of the willow, the vegetative composition is varied. The area immediately north of the island, still supports a mixed stand of river bulrush, small-fruit bulrush, soft rush, buttercup and reed canarygrass. The drainage channel, along the east side of the island, has willow and emergent plants, but is still dominated by reed canarygrass. The area west of the island, which was planted to river bulrush, has a mix of soft rush, river bulrush, three-square bulrush, cattail, and reed canarygrass. During the winter 1994- 1995, willow had not become established in this area. The depression, west of the island and the backwater area to the west of this, still have a predominance of mixed emergent marsh plants, with a mixed (but relatively dense) stand of reed canarygrass becoming established. The dominant plant is still soft rush, with willow becoming scattered throughout. Pacific willow, which is planted on the island, is growing and may be contributing to the spread of willow in this area. The open-water component, south of the island, is still covered with water during the early stages of the year, up to approximately June 15. Beyond June 15, the area goes dry, leaving an un-vegetated mud flat. Willow weed became established in this area in early August, once the water was shallow or gone, and the mud was still saturated. The willow weed expanded across the area and stayed viable to the end of the growing season. Reed canarygrass and scattered patches of cattail are starting to become established in this area. 2 June 6, 1995 The Koll Company RE: 1994 Monitoring Report - Koll North Creek By-Pass channel Wetlands The area south of the log structure is still dominated by a near monoculture of reed canarygrass. The channel, extending from the rock structure to the creek is so overgrown with reed canarygrass, that it is impossible to observe water movement in this area. Willow, black cottonwood, red-osier dogwood, and Pacific ninebark, which are planted along the stream, are still alive and competing with reed canarygrass. There are places where reed canarygrass extends over the creek and forms an over-hanging canopy. In other areas, the willow cover has shaded out the reed canarygrass, providing a shrub overstory, with limited ground cover. Black cottonwood are spreading on the flat, south of the dike, and along the west side of the mitigation area. Photographs 1 through 10, Appendix A, document conditions during the summer and fall of 1994. It is evident, from on-going activities, the willow will eventually be the dominant species over most of the overflow/back- water by-pass area, with the exception of the north end, where the area is drier and the reed canarygrass is dominant, and the area south of the island, where the water remains for much of the summer. The open water and deeper component south of the island will also remain open or become established with an emergent marsh species that is more tolerant to seasonal inundation. The species that are currently growing in the area include cattail, hard-stem bulrush and reed canarygrass. Wildlife Use Three site visits were completed -- two during the summer months when foliage was on the trees, and one in the winter when the deciduous trees were barren. Nests were located, counted, and (when possible) identified. An effort was made to count only nests which showed current activity (not filled with leaves or showed evidence of winter degradation). The wildlife study was extended to the stream and stream corridor to monitor the overall wildlife utilization of the wetland 3 June 6, 1995 The Koll Company RE: 1994 Monitoring Report - Koll North Creek By-Pass channel Wetlands and stream habitat component. No survey was conducted in the trees or shrubs surrounding the detention pond; however, records were kept of all birds and broods observed on the pond. Wetlands Waterfowl broods and the majority of waterfowl activity, recorded during the summer of 1994, was recorded when there was water in the open-water component and in the backwater areas that had formed in the wetlands adjacent to North Creek. During the summer and fall, the dominant wetland bird activity, i.e., ducks and geese, was in the stream. Only five (5) broods of mallards, one (1) brood of pintail, and a brood of gadwall were observed. Six (6) broods of Canada geese were observed in the area. Because of their behavior, it was determined they were probably hatched on the site and were not migrants from upstream to the north. The island was examined for goose nests. Two nests that were present in 1993 were present; however, the southern-most nest appears to have been destroyed by a predator. This was determined by the condition of egg shell and the early abandonment of the nest, allowing grass to grow up through the nest. Birds that loafed on the open-water component, south of the island were predominantly mallard and pintail, with an occasional Canada goose. During fall migration, a wave of approximately 100 first year pintail spent about 10 days on the site.' These were mixed with early migrant green-wing teal and local mallards that had moved from more open streams into this area for protection. After the first rainfalls, when the open-water component at the south end of the island became flooded, the bird activity increased on a day-by- day basis, with birds moving in, apparently for protection during the night, then moving out to feed. In the fall, when the water dropped and the mud-flats south of the island were exposed, the area was visited by dunlins, western sandpipers, and killdeer. No shorebirds were observed using the site, once the by-pass channel flooded. Because of the log structure, the water reached a depth of one foot to 18 inches fairly rapidly in this area, which would prevent utilization by ' Personal contact with local "birders." 4 June 6, 1995 The Koll Company RE: 1994 Monitoring Report - Koll North Creek By-Pass channel Wetlands most shorebirds, which are limited to very shallow water or mud- flats. Great blue heron were seen along the creek and in the by-pass channel, during the period when the water was decreasing and the area was going dry. It is believed they were catching frogs; however, there are no observations of actual feeding activity. Heron also used the area along the creek and the retention/detention pond. An assortment of waterfowl used the detention pond. During the spring migration, the area was visited by mallard, pintail, gadwall, bufflehead, teal, lesser scaup, and shoveler. For the first time in four years, no rail were observed in the retention/ detention pond area. Snipe, however, were nesting in the grass at the edge of the lawn area, adjacent to the clubhouse. At least one brood of snipe were none to be hatched. Non-wetland Birds Non-wetland bird nesting was limited to identification of nests in the trees and shrubs and from observations of young birds being fed during the summer visit. As has been identified each year, the most common nests were robin. Swainson's thrush nests were either hidden or there was a reduction of thrush activity on the site. At least three species of sparrows are believed to have nested in the trees or in the grass area. Long-billed marsh wren and winter wren nests or breeding pairs were observed along the creek and in the area of the retention/detention pond. There appears to be chickadee and nuthatch nesting in two of the older snags, which are becoming decadent. The top blew out of one of these, eliminating a single downy woodpecker nest, which was identified in 1993. With the increase in the size of trees, the woodpecker activity continues to be relatively common. Two most common species observed were the downy woodpecker and western flicker. Ring-necked pheasants nested on the island and in the reed canarygrass area, at the north end of the site. 5 June 6, 1995 The Koll Company RE: 1994 Monitoring Report - Koll North Creek By-Pass channel Wetlands Total birds observed, nesting results, and waterfowl use daysz are recorded on Tables 1-3, Appendix B. Mammals For the first time in three years, no coyotes were recorded on this site, although there is a high probability they are present, since they were observed in the dairy area to the north. Columbia black-tailed deer moved in the area and were seen in the backwater area, in the midst of the willows. With the increase of willow shoots, it is expected that gnawing and browsing mammal use could increase. Conclusions The diversity of vegetation within the backwater area is slowly decreasing with reed canarygrass and willow becoming the two dominant species. The only area with a distinct absence of these two species is the seasonally flooded, deeper area at the south end of the island. Reed canarygrass is slowly disappearing in certain areas along the creek bank, as the shade increases. However, the overflow channels adjacent to the creek are still dominated by the grass. With the amount of reed canarygrass north of the site and the amount of seeding reed canarygrass on the site, it will be impossible to reduce or eliminate the reed canarygrass. With the increase in willow and the density of downed reed canarygrass, the foraging habitat for waterfowl and other seed eating or probing birds is gradually reducing. Currently, the expanding willow stand has not reached a level of maturity where it can provide nesting habitat or cover for birds or mammals. The reed canarygrass is providing excellent water quality treatment. The amount of sediment and silt in the reed canarygrass portions of both the overflow channel (adjacent to the creek) and the south end of the by-pass channel, indicate that during winter floods, when there is heavy amounts of silt and other contaminants from the north in the water, the area does filter out large amounts Assumes birds observed for one day on the site equals one use day - U.S. Fish & Wildlife Service. 6 June 6, 1995 The Koll Company RE: 1994 Monitoring Report - Koll North Creek By-Pass channel Wetlands of sediment from the water, before it passes down-stream to Sammamish Slough. Wildlife use is still high. The majority of use is in the riparian border, adjacent to the creek; the shrub area around the detention pond; the open-water area at the south end of the island, during the winter when there is sufficient water; and in late summer, when the area becomes a rich insect-ladened mud-flat. This completes the 1994-95 Monitoring Report for North Creek, with an emphasis on North Creek By-pass Channel vegetation. Sincer y, Z?)eq?? R. L. "Rex" Van Wormer Senior Biologist IES Associates Holl.mon 7 Appendix A - KOLL NORTH CREEK PHOTOGRAPHS Photo 1 - Looking southeast, across the By-Pass Channel wetlands from the northwest corner; note reed canarygrass and willow stand (June 1994). Photo 2 - Looking southeast in the By-Pass Channel, showing willow in summer of 1994. Photo 3- Looking south from the south edge of the willow stand at the open-water component, island, and mixed canarygrass/ soft rush area, at the south end of the By-Pass Channel mitigation area (June 1994). Photo 4 - Deep-water component south of island at the south end of mitigation area; note waterfowl use (June 1994). •'"t c • , Abo T' Photo 5 - Taken from the north northeast. edge of Koji Creek, looking Shows density of reed canarygrass in area surrounding the center core of wetland. Photo e - Taken December '94 canarygrass and willow stand wingBy-Pass 1Channelewetlanda Photo 7 - Willow stand in winter; showing density and height of Sitka willow. Photo 8 - Looking north, along the east side of the island; showing open-water, emergent-marsh component blocked in by reed canarygrass (winter 1994-95). Photo 9 - December '94 - Overflow channel, showing the invasion of reed canarygrass. Photo 10 Red-osier dogwood/willow stand at the edge of creek, with reed canarygrass in the overflow area. Appendix B - TABLES Table 1. Stream Bank Nesting' Non-Waterfowl Species Year 1 Year 3 Year 5 1993 1994' Common Bushtit 0 0 2 0 0 Fox Sparrow 0 3 2 0 1 Junco 1 4 5 1 4 Lng-bill'd Marsh Wren 0 2 3 2 2 Robin 4 4 7 11 14 Rufous Hummingbird2 0 0 1 1 0 Song Sparrow3 1 3 6 4 3 Starling 0 0 2 0 0 Towhee' 0 2 6 2 1 White-crown Sparrow 1 0 0 0 2 Winter Wren3 0 3 5 4 6 Yellowthroat3 0 3 7 2 1 Swainson's Thrush 0 0 0 5 2 Oriole (spp) 0 0 0 2 0 Ring-necked Pheasant 0 0 0 2 3 ' Based on limited surveys. 2 Only nest located 3 Based on territorial males. a Based on young birds. 2 Table 2. Backwater Wetland/Stream Bank Shorebird and Wading Bird Use' Pre- Species Const Year 1 Year 3 Year 5 1993 1994 Dunlin 0 25 50 280 40) )- - 75 Lng-bill'd Dowitcher 0 0 0 40 77) Great Blue Heron 4 6 7 5 7 9 Green Heron 0 0 0 3 1 2 Killdeer 4 10 15 28 14 10 Least Bittern 0 0 0 1 1 0 Lesser Yellowlegs 0 0 3 10 18 6 Semipalmated Plover 0 0 0 11 0 0 Spotted Sandpiper 0 6 6 10 6) ) -- 40 Western Sandpiper 0 0 10 200 119) s Maximum number at any one time. 3 Table 3. Backwater Wetland/Stream Bank Waterfowl Use Pre- Peak Use Total Const Numbers Days Broods Youn 6 Year 1 50 2250 0 0 Year 2 850 47,500 10 53 Year 3 1140 63,400 16 72 Year 5 900 64,000 15 68 1993 Ducks 1150 41,400 10 52 Geese 200 4,000 6 19 1994 Ducks 400 12,600 6 32 Geese 30 600 3 10 6 Field Counted. 4