Students: Joe Sandstrom, Racquel Karl, Ly Nguyen, Jessica Carver, Robert Ellis
Faculty Advisor or Community Project Lead: Osama A. Abaza
Alaska Department of Transportation and Public Facilities (AK-DOT&PF)
Seawolf Engineering has been asked to design upgrades to the existing Parks Highway intersection with Big Lake Road, located at approximately MP 52 of the Parks Highway.
The sustained growth in the Matanuska-Susitna Borough in the past few years has resulted in a corresponding increase in highway traffic through the project area. This has resulted in increased crashes and fatalities in the project corridor, which have necessitated the improvement of the project intersection.
The project area includes the intersection of Big Lake Road and the Parks Highway and extends approximately 0.5 miles both ways from the intersection along the Parks Highway, as well as 0.25 miles from the intersection along Big Lake Road. The Parks Highway is a rural interstate highway that begins with an intersection of the Glenn Highway east of Wasilla and continues to Fairbanks, a distance of 324 miles.
Proposed improvements include construction of a signalized intersection at the intersection of Big Lake Road and the Parks Highway, which will also facilitate pedestrian and bicycle traffic. In accordance with the Environmental Assessment, the crossing of Little Meadow Creek will be relocated to its historical flow channel just to the north of the intersection, and a bridge will be installed over it. This will allow the creek bed to be returned to a more natural state and provide a crossing for local wildlife below the Parks Highway.
The signalized system is able to control a large area to accommodate the flow of traffic for both pedestrians and vehicles. This will reduce angle collision accidents, provide the maximum degree of control at the intersection, increase the capacity of handling traffic, induce an orderly flow of traffic, and reduce delays through the intersection. Due to a dramatic increase in volume for the design year, this design provides two left turning lanes from Parks Highway into Big Lake, additional through lanes on Parks Highway, separated pathways, and pedestrian crossings through the intersection.
Currently, Little Meadow Creek crosses though a 78 inch CMP culvert with a 48 inch overflow culvert. These will be replaced by a single span bridge. A double-crossing bench was designed to provide dual crossings for wildlife and pedestrians to cross under the roadway as well as recreational fishing in Little Meadow Creek. The open surface of the creek allows for a more natural crossing design for fish. The crossing under the bridge design was analyzed using HEC-RAS software. The analyses showed the design is feasible and will lower the 100 year flood event water surface elevations.
The US Army Corps of Engineers (USACE) Clean Water Act Section 404 Permit is required for this project because the project encompasses a portion of Little Meadow Creek and its surrounding wetlands. Seawolf Engineering minimized impacts to Little Meadow Creek and wetlands by preparing an ESCPand and USACE Section 404 Permit in accordance with the Environmental Assessment and Construction General Permit.