Magnuson Wetland Overlook
The operating hours for Magnuson Park vary with the seasons. From May 1 to Labor Day, the park is open from 4 a.m. – 11:30 p.m. From Labor Day to April 30, the park is open from 4 a.m. – 10 p.m.
The first and only waypoint for this multi-cache is a stop to gather some information at a sign near the top of a hill that overlooks the Magnuson Wetland Complex. There is a gently sloping gravel trail that leads to the top of the hill, as well as two steeper social trails. All of the information on the cache page was taken from various informational signs throughout the wetland complex.
The Sand Point Peninsula, known today as Magnuson Park, was once covered in wetlands, lowland forest, and even a small lake. The site was forever altered in the early 1900s, when the Lake Washington Ship Canal opened, lowering the lake by nine feet. The forest and wetlands were also dramatically altered when the peninsula was graded from rolling hills into a flat plain to serve as a Naval Air Station. Water from the surrounding hills and the site itself was diverted into underground pipes, essentially turning wetlands to dry land.
Today, Magnuson Park is reversing that action, making storm water a unifying element in the park. Starting at the hills and historic structures and weaving its way eastward through sports fields and ponds, storm water now moves through re-created wetlands. These wetlands provide wildlife habitat and improve the water’s quality before it enters Lake Washington.
Unfortunately, the park cannot restore the once-pristine conditions of the former wetlands. The marsh ponds visible at this first waypoint are anything but natural. As man-made as the runway that once stood here, they fill and overflow, one into the next, in a manner similar to rice paddies. This condition provides a broad range of habitat functions. While the shapes of the ponds begin as squares, oriented along an airstrip once on this site, their forms become more organic to the east. Regardless of their shape, they all provide valuable habitat that will evolve into an increasingly complex ecosystem over time.
The Magnuson Wetland Complex was largely built around existing stands of red alder and black cottonwood. These groves naturally established themselves after the naval station was decommissioned. While their location appears random, these trees established themselves on soils that were less impacted by the airstrip and the decommissioning process. Retaining these older trees provided a 30-year head start on re-establishing forests. The trees maintained valuable habitat throughout the wetland construction and created a microclimate that still benefits the establishment of new vegetation. The marsh ponds are emergent wetlands and are only seasonally wet. They fill up from rains in late fall and maintain a stable water level until rains cease in late spring. They dry out in summer, as do many natural marshes.
While you are at the first informational sign, you will need to make some calculations to determine the coordinates for the final cache location:
What year was the older photograph taken? ABCD
F = A + C
E = D – A
The final cache container is located at N 47° 40.FFE, W 122° 15.FAC
Enjoy your walk through the Warren G. Magnuson Wetlands!