Best Water/Environment: Utah Lake State Park Marina Dredging
Utah Lake State Park Marina Dredging
Owner: State of Utah DFCM
General Contractor: Geneva Rock Products
Civil Engineer: JUB Engineers Inc.
The marina at Utah Lake State Park was often closed to water recreation because of low-water levels, exposing massive amounts of mud. This dredging project restored the functionality of boating amenities by deepening the marina and the channel by 4 ft. A cofferdam was installed before fish in the lake were rescued and removed, including the endangered June sucker fish.
Fifty million gallons of water were then pumped out of the marina to allow for removal of 60,000 cu yd of mud. All excavated material was hauled to an onsite dump, where it was scattered and allowed to dry for later use. Water was pumped back into the marina and the dams were removed. The result is a 4-ft-deep waterway from the harbor to the lake that allows boats to safely access the marina.
Crews were continually challenged to keep water out of the harbor while they battled wind and ice that crushed Conex boxes and moved concrete anchors. After high winds blew ice flows across the lake and destroyed four bladder cofferdams, the team realized that the only way to continue dredging in those conditions was to install an earthen dam.
To ensure accurate dredging, crews used a static LiDAR system to compile a surface profile. They then created a model and lowered it vertically 4 ft to provide a target surface for excavation. This surface model was loaded into a machine-grade control system that had been installed on the excavators. This system gave operators a way to excavate the sediment, sometimes in the water and sometimes beneath it, to a neat line grade. Utilizing this system, the team excavated to within 2% of the calculated quantity of material.
The contractor credits design-build delivery with the opportunity to survey and track quantities on the project. The combined use of LiDAR and machine-grade controls also served as the basis for an accurate set of as-builts for the owner’s records.