Hylebos Wetlands Sinkhole - Federal Way, Washington
Posted by: 
Hikenutty
N 47° 17.253 W 122° 19.569
10T E 550954 N 5237339
This sinkhole in a peatbog was formed due to contact with the oxygen in the water. It is 20 feet deep and is home to the native red-legged frog and an endangered variety of sedge.
Waymark Code: WM1CQ0
Location: Washington, United States
Date Posted: 04/06/2007
Views: 128
This sinkhole has been named the Hylebos(High-luh-bohs) Deep Sinks and it began its formation soon after the last glaciation of this area. When the ice retreated some 10,000 to 15,000 years ago it left a large lake that gradually filled with sediment and plant material. At some point it became dry enough to support forest growth.
Peat forms in low oxygen conditions. The plant matter is unable to fully decompose, due to lack of oxygen and the layers build up. This particular bog is 30 feet thick and it is one of few of the old type of peatbogs left. Most were mined for their peat years ago.
This sinkhole is located in West Hylebos Park, which in turn is part of the Hylebos Watershed. The city owned park features a boardwalk trail meandering through the wetlands. There are interpretive signs along the trail, along with many benches and in one section, a bird blind. The area is home to several pileated woodpeckers and a host of other flora and fauna. Be sure to click on the gallery, because there are more pictures than the 5 showing. We took pictures of a rabbit on the way in and also some great fungi and flowers. There is a wonderful multi-cache in this park so be sure to check that out too.
The park entrance trail is located next to the site of 2 historic cabins. There is parking at the cabins at N47 18.077 W122 21.782.
Follow the trail that winds aroud the right, smaller cabin. This trail will wind around until you reach the trail register at N47 17.271 W122 19.713. From here follow the trail next to the kiosk and take a left at the first junction. Continue following the boardwalk and you will reach the above coordinates.
Visit Instructions:
Please provide a photo of you and/or your GPS at the site.