By: Clay Prewitt
H2 Pre-Cast Inc.
H2 Pre-Cast Inc. supplied split box sections for construction of a box culvert used for fish passage on the North Fork Issaquah Creek under the East Lake Sammamish Parkway in Issaquah, Washington. The 26-foot x 11-foot precast concrete culvert was installed in just three days. The original installation schedule required a full six-day closure of East Lake Sammamish Parkway and lane closures on the Front Street ramps to I-90. The parkway was open to traffic two days ahead of schedule on June 16, because of the accelerated precast construction made possible by the experience of the contractor, Scarsella Brothers, Inc., and the precast design. The new culvert replaced a series of three (each 3-foot wide) culverts that were a barrier to fish passage.
A split box culvert is a two-piece, four-sided structure having a U-shaped bottom section and a precast concrete lid. Split culverts have a wide variety of applications other than fish passages, including managing stormwater at underpasses, service tunnels, subways, and small bridges.
The box culvert was installed at a new creek location underneath East Lake Sammamish Parkway. A second culvert was built underneath the nearby I-90 highway to give the local migratory trout and salmon additional access to a nearby offshoot of North Fork Issaquah Creek.
Existing culverts were a barrier to migratory salmon. Water flows are occasionally too low or strong for fish to navigate upstream. Moving the creek so it crosses the highway once and installing a wider culvert allowed the creek to flow naturally under the highway and improve the fish habitat in the area. The fish passage project is one of about 1,000 culverts across Washington State that are mandated to be replaced. In 2013, the U.S. District Court for Western Washington ruled that the state must remove culverts that block fish passage under state highways. The Issaquah Creek realignment and culvert project opens almost a mile of additional fish habitat.
This is a demonstration of the comparative flammability of polypropylene pipe (PP), reinforced concrete pipe (RCP), and high density polyethylene pipe (HDPE). Dry hay is ignited in three 18 in. by 18 in. pipes and allowed to burn. This is an unedited test conducted on October 21, 2015.