Case Study: Aquatic Weed Harvester Protects Salmon Spawning Grounds

BACKGROUND INFORMATION

Located just outside Valdez, Robe Lake is an important part of the Valdez ecosystem
Slow moving with a gravel bottom creates the ideal spawning ground for salmon
Freshwater lake with three tributary streams leading to Prince William Sound and eventually the Pacific Ocean
Lake ecology changed and weeds grew on the gravel bottom spawning beds
Valdez Fisheries Development Assn operates one of the largest fisheries programs in North America with a $100 million economic impact

Robe Lake is a great locale for wildlife viewing.

PROJECT CHALLENGE

Aquatic vegetation causes oxygen depletion and the loss of spawning habitat
Dense plants grew at the mouth of the Robe River blocking access upstream
Very shallow water and narrow channels

THE SOLUTION

The barge style HM-420 Aquatic Weed Harvester with swing to stern paddle wheels has a low draft and narrow operating width allowing the Harvester access to operate around Robe Lake and on Robe River.

Transitioning from mid-ship paddle wheels to stern operated.

HM-420 with swing to stern paddle wheels.

Aquatic weed harvester and approaching float plane

Aquatic Weed Harvesters and Offloading Conveyors are installed on both lakes with the larger of the lakes operating a second harvester as well as a Transport Barge. The Lakes Rehabilitation District has collected over 20 years of aquatic plant harvesting data and while there is still nuisance vegetation, it has significantly reduced.