Dillon Reservoir Is 280 Feet Deep. Divers Can Work 80 of Them.

Dillon Reservoir is the largest storage reservoir in the Denver Water system, and at its deepest point it is 280 feet deep. The Summit County Sheriff’s Office puts the practical limit for its divers at 80 feet. The gap between those two numbers is not a training problem or an equipment budget. It is elevation.

Dillon sits about 9,000 feet above sea level. Sergeant Mark Watson of the Summit County Sheriff’s Office told Denver Water that below 80 feet, going down requires specialized divers, specialized training, and specialized equipment, and that it gets expensive fast. So the agency bought a machine instead.

A Five-Pound Tool for a 280-Foot Problem

The device is a remote operated vehicle built by VideoRay, towed behind a boat on a cable. It carries side-scan sonar, lights, cameras, and a claw. It weighs about five pounds, measures under two feet long, and cost roughly $60,000. It is rated to 1,000 feet, which is more than three times the deepest water in the reservoir it was bought to work.

When Denver Water published the piece, Summit County was the only public agency in Colorado with an underwater drone of its own. Denver Water had used similar camera systems to inspect the underwater equipment that operates its dam, according to chief dam safety engineer Darren Brinker.

Finding Is Not the Same as Recovering

Watson was clear about what the machine does and does not do. It is not meant to replace divers. It locates an object, marks the position, and then the dive team gets called if the job needs one. The claw can retrieve small items. A boat engine that went into the water at Dillon is the kind of thing it found.

A vehicle is a different category of problem. Sonar can put a truck on a screen in fifteen minutes. Rigging that truck so it comes up in one piece, without tearing open a fuel tank on the way, is diver work, and at altitude the clock on that work runs faster. Altitude shortens no-decompression limits. Every foot of depth costs more bottom time in a mountain reservoir than it does at sea level, which is exactly why the 80-foot line exists.

Utah Has the Same Ceiling

Fathom Restoration is a disabled-veteran-led Utah 501(c)(3) nonprofit, and we are a diver organization first. Our mission is the recovery of submerged vehicles, vessels, and debris from lakes and waterways across the state, and the water quality that depends on getting them out.

Utah’s reservoirs sit at altitude too. Deer Creek Reservoir is at roughly 5,400 feet. That is thinner air than Colorado’s high country but it is not sea level, and it moves the same limits in the same direction. Any honest plan for Utah lake cleanup has to be built around what a diver can actually do at elevation, not around what the depth chart says.

What sits down there does not wait. A vehicle on a lakebed is a fuel tank, engine oil, ethylene glycol, and a lead acid battery inside a housing corroding around all four. Under the Clean Water Act, a discharge that leaves a visible sheen on the surface is reportable. The U.S. Geological Survey has tracked petroleum contamination persisting in groundwater for decades at its long-running research site near Bemidji, Minnesota.

We built the Utah Waterways Submerged Debris Atlas to keep the list. It documents an estimated 499 submerged items across 20 Utah lakes, 226 of them confirmed individually, including 103 vessels and 56 vehicles.

We are building toward doing this recovery work ourselves, and we are direct about the order it happens in: recovery-specific insurance, sovereign lands permits, and commercial dive certification, before a single lift. Altitude is one more reason that order is not negotiable.

Technology finds things. People bring them up. If you have seen a submerged vehicle, vessel, or debris pile in a Utah waterway, report it at fathomrestoration.org.

Fathom Restoration is a disabled-veteran-led Utah 501(c)(3) nonprofit dedicated to lake cleanup and the recovery of submerged vehicles, vessels, and debris from Utah’s lakes and waterways. Donate / Volunteer / Report a vehicle at fathomrestoration.org.

Source: https://www.denverwater.org/tap/underwater-drone-takes-the-pressure-off-dive-teams