Case Study: Trash Hunter Removes Debris Interfering with Fish Passage Facilities


  • Four hydroelectric facilities produce 550 megawatts of hydroelectricty
  • The facilities consists of 174 miles of streams with a total drop of 7,900 feet
  • The drainage basin area is 1,050 square miles consisting of forest and wildlife habitat
  • Fish passage through the dams was a major environmental concern; fish passage facilities sort and transport fish either upstream or downstream

View of the Lewis River in southern Washington State.


  • Surrounded by forest, heavy rains wash large wooden debris into the river system
  • Wooden debris clogs the fish collection system, leading to costly shut downs
  • Equipment must include spill protection and noise reduction
  • Travel to the facilities consist of forest roads and the equipment needs to move from one location to another


The Lewis River Hydroelectric Project, designed to meet the electrical needs of customers, operates two fish passage projects and funds operations at three fish hatcheries to support and improve the production of wild migratory fish.

Launched upstream from a fish passage facility, the Aquarius Systems TH-23 Aquatic Debris Skimmer collects floating debris trapped by a trash boom before the dam, intake and fish collectors.

Trash Hunters easily retrieve a wide variety of manmade and organic floating debris including litter, old tires, plastic, branches, and logs.

Launching the TH-23 Aquatic Trash Hunter into a reservoir.

This process prevents debris from blocking fish passage. By ensuring they can move freely and safely through, the Trash Hunter aids in fish migration and population growth. The debris removal also helps prevent clogging and equipment damage, ensuring the efficient operation of the facility.