For the first time in more than a century, boaters and paddlers will soon be able to float the Green River between what became Flaming Gorge and Lake Powell reservoirs, thanks to the reconstruction of a historic diversion dam.
To the delight of river runners, federal authorities agreed to include a boat passage, as well as fish ladders, on the new Tusher Diversion, which becomes operational this week. Recreation advocates hope the project will enable more boaters to float the dozen miles upstream from the river's namesake town and increase take-out traffic at Green River State Park.
However, the state Department of Natural Resources has concerns about the passage's safety and wants to study how it performs before encouraging the boating public to run it, particularly at high water.
But melon growers and endangered fish don't have to wait to benefit from the rebuilt dam, the fruit of a multi-agency collaboration covered mostly by federal dollars.
In a public ceremony Wednesday, the state and federal agencies behind the $7.7 million project will remove the coffers and dedicate the dam. The event is at 11 a.m. on the river's west bank, accessed from Long Street, north of town.
"This dam will provide a secure supply of irrigation water for the many farmers, ranchers and secondary-water users in this area well into the future," said Utah agriculture commissioner LuAnn Adams. "Water in the West can make or break a community, and this dam literally keeps the green in Green River, Utah."
It will also keep the green in farmers' wallets, since the river supports Grand and Emery counties' $20 million agricultural industry. The Tusher Diversion waters 5,300 acres that produce many of the cantaloupes, casabas, honeydews, canary and other melons for which the Green River is known.
Settlers built the U-shaped rock-and-crib weir more than a century ago to divert some of the Green's flow onto fields. But the low structure also obstructed the movement of boats and various fish species that have since come under federal protection. Most boaters had to portage the dam or take out at Swasey's Beach, a few miles upstream. Intrepid boaters could run over the weir at certain water levels, but such a move was perilous, as the right side of the channel is littered with rebar-studded concrete and the left side is strewn with boulders disgorged from Tusher Wash.
High waters following the wet winter of 2011 hammered the aging dam, putting it a risk of a failure that would have dewatered the three canals exiting the river. The Natural Resources Conservation Service, an agency of the U.S. Department of Agriculture, targeted it for reconstruction under its Emergency Watershed Protection program, which has committed $93 million in recent years to fix and build dams and catch basins damaged in the wake of Utah's wildfires, floods and other disasters.
The initial Tusher plan did not call for a boat passage and river runners quickly mobilized, lobbying for features that would enable boaters to replicate the Green River portion of the 1869 expedition led by John Wesley Powell.
Officials agreed a boat passage was warranted and the Utah Division of Forestry, Fire and State Lands (FFSL) put up the $153,000 to help cover increased costs. As a result of such investments, the replacement diversion is far superior to the historic structure.
"That shows the benefit of taking time. It was over two years. Some might look at it as a downside, but the positive is it allows partners, community and interest groups to express their interests and allows us to incorporate it into our design," said Dave Brown, the Utah conservationist for the Natural Resources Conservation Service.
"We showed up and participated in the discussion," said Nathan Fey of American Whitewater. "The state advocated for boater safety. It was no longer an issue of fish versus boaters."
An archaeologist monitored the historic dam's demolition in an effort to document its construction and design for an exhibit proposed for Green River's John Wesley Powell River History Museum.
The new design also features screens to keep fish out of the diversion canals, as well as three fish passages — one for upstream swimmers and two for downstreamers — equipped with readers to count fish that have been injected with tiny electronic tags. This aspect of the project was funded and designed by state and federal wildlife agencies hoping to recover native humpback chub, Colorado pike minnow, razorback sucker and bonytail.
The state secured water rights that should ensure that water passes through the 25-foot gap at a rate of at least 147 cubic feet per second.
Now that the project is complete, however, the passage does not appear to be functioning as hoped, according Jason Curry, spokesman for the Utah Division of Forestry, Fire and State Lands.
"Something about the dam looks a little more treacherous than intended," Curry said. "It doesn't look like it's 100 percent safe for all boats. We would like it to be negotiable for all traffic. The main thing was to make it safe. We will do test runs to see how the hydraulics work. ... It might need some modifications."
A few miles upstream, Swasey's Beach boat ramp is a busy take-out where the 560 parties that float Desolation Canyon each year exit the river. That accounts for 5,500 and 6,000 people, while an unknown number of people run day trips from Nefertiti to the Swasey take-out, according to the Bureau of Land Management.
When the new passage opens, boaters can extend their trip past Swasey's Beach for the 12 river miles on relatively flat water to town, or put in at Swasey's. Because the current is so slow, this stretch is recommended for canoes and kayaks.
Brian Maffly covers public lands for The Salt Lake Tribune. Maffly can be reached at bmaffly@sltrib.com or 801-257-8713.
Twitter: @brianmaffly