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North Creek Tour — November 2004

By Holly Zox

Now that our rainy season should be well under way, why not see where all that water goes. Pick a rainy day for this tour of what has been Washington’s fastest urbanizing watershed, Snohomish (and King) County’s North Creek.

Meltwaters flowing beneath the various advances and retreats at the end of Pleistocene glaciation carved a series of north-south valleys in the Puget lowlands. Before European settlement, North Creek would have meandered through one such valley, the hills covered in forest that would intercept precipitation, slow runoff, and allow some water to infiltrate and recharge the aquifer that fed the creek. The floodplain would have largely been forest of western redcedar (Thuja plicata), western hemlock (Tsuga heterophylla), Douglas-fir (Pseudotsuga menziesii), Sitka spruce (Picea sitchensis), red alder (Alnus rubra), and black cottonwood (Populus balsamifera ssp. trichocarpa), with a patchwork of scrub-shrub and emergent herbaceous wetlands, especially near the once marshy mouth, steeper now that Lake Washington is some 12’ lower than it was before construction of the Lake Washington ship canal and locks in 1913-1916.

All that timber proved irresistible to European settlers, and North Creek was straightened to float logs to market. Gone were the sources of coarse woody debris, which provided food and habitat for the aquatic ecosystem, including salmon, gone the habitat diversity of ripples and pools, backwater channels, and ever-shifting stream banks, and into the floodplain came farms and cattle pastures of invasive reed canary grass (Phalaris arundinacea), planted as a high quality forage grass in wet pastures. Houses and strip malls grow more money than trees and cows. Now the watershed is largely developed and covered in impervious surfaces, precipitation reaches the creek in mere hours and the hydrology, both flow and chemistry is altered forever.

Begin our tour in your mind, at the Everett Mall, site of North Creek’s headwaters. Then take I-5 exit 186 (128th St SE) 1/2 mile east to the entrance to McCollum Park on the south side of 128th. Drive past the pool and park near the WSU Extension offices at the south end of the park. Former site of a garbage dump; McCollum Park also contains a lovely remnant of second-growth forest for North Creek to meander through, and the headquarters of the Adopt-a-Stream Foundation. Enter the woods by crossing a bridge over North Creek. Wander through the redcedar/hemlock forest, with Douglas-fir, Sitka spruce, black cottonwood, red alder, vine maple (Acer circinatum), salmonberry (Rubus spectabilis), sword fern (Polystichum munitum), and piggyback plant (Tolmiea menziesii). See also plenty of dead stuff: snags and stumps, upturned root boles, and decaying logs.

Though just a small fragment, and always under the influence of its edge, the forest is not all the same. Evergreens sword fern, salal (Gaultheria shallon), and dwarf Oregon-grape (Berberis nervosa) make up most of the understory in the drier areas. Some areas, perhaps too dry and/or too dark, have virtually no understory. The most complex structure is found nearest the creek. Increased disturbance from fluctuating water levels

creates a diversity of conditions, with horizontal openings. Increased moisture and nutrients support a deciduous shrubby understory for vertical complexity. A 1.35 acre freshwater marsh reclaimed by Adopt-a-Stream from a gravel parking lot, adds to the diversity.

For more marsh, drive east on 128th St SE, which soon becomes 132nd St SE, 1/2 mile to 527 South. Take 527 South about 3.5 miles and turn west (right) onto 183rd St SE and drive 1/2 mile to North Creek County Park. Thousands of years of layering of poorly decomposing plants in the oxygen-poor soil of this glacial valley have resulted in peat deposits 20' thick. First homesteaded by the Bailey family in 1891, the land was used to raise cattle and mine peat. Now the wetlands serve the valuable functions of collecting and cleansing surface water and regulating flash floods. On a rainy day the boardwalk trail floats on runoff from the watershed’s impervious surfaces.

Look down at the valley and see a mosaic of dueling plants adapted to vegetative reproduction. Walk down the trail and encounter reed canary grass. Native “thugs” like hardhack (Spiraea douglasii) and cattails (Typha latifolia) muscle in on the exotic reed canary grass and creeping buttercup (Ranunculus repens)/ soft rush (Juncus effuses) communities. Nice colonies of inflated sedges (Carex utriculata and C. vesicaria) can also be seen. Numerous emergent and aquatic bed wetland plants, such as small bedstraw (Galium trifidum) and duckweed (Lemna minor) can be found along the boardwalk and in the ponds of this fine urban park.

Next, drive back to 527 and head south another 2.5 miles to 405 South. Take 405 South to exit 24 and turn right onto Beardslee Blvd, and drive 1/8 mile to the entrance to the University of Washington-Bothell/ Cascadia Community College campus at the distal end of North Creek where it joins the Sammamish River on its way to Lake Washington. The campus wetlands are an ambitious restoration to reconnect North Creek with its floodplain. The 58 acre floodplain restoration covers nearly 1/2 the campus and is mitigation for about 6 acres of hillslope wetland filled for building. The restoration is not just plants. Considerable efforts went to restore physical, chemical, and hydrological features and processes to transform pasture and farmland with a straight channel confined within levees into a dynamic floodplain with meandering primary and secondary channels which flood, and complex, gently sloping surrounding topography with microdepressions. Two hundred sixty-one polygons were then planted in a mosaic of forested, scrub-shrub, and emergent wetland communities from fall 1998 to spring 2002. Environmental science students help with ongoing monitoring of this living campus laboratory.

To view up close, walk the Regional Trail, stopping at interpretive signs and the viewing platform at the end of the boardwalk. See logjams, bank and bed features, and riffles and pools in the creek. Pioneer plants like red alder and Pacific and Sitka willows (Salix lucida ssp. lasiandra and S. sitchensis) have been especially successful. Birdsong from hardhack and willow thickets almost drowns out the roar of the freeway above.

All told, these 3 sites include about 3 miles of flat walking. At the end of the day, one can be both dismayed that the uplands have lost much of their protective mantle of forest, and encouraged by the multiple efforts to support the floodplain of this urban watershed on more of a landscape scale.

Updated: July 3, 2016
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