'A disaster for Grand Lake'

It's touch-and-go for state's 'most gorgeous' body of water

Todd Hartman, Rocky Mountain News

Published October 4, 2004 at midnight

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GRAND LAKE - One of Colorado's rarest jewels glimmers with snowmelt pouring off the Never Summer Mountains and into the watercourse that winds through the pastoral Kawuneeche Valley.

It's Grand Lake, the state's largest natural body of water, not a manmade reservoir like most of Colorado's destination waters.

But residents living along the shore complain that the deep blue waters of Grand Lake aren't as icy-pure as Mother Nature intended. And they're blaming the impact of water diversions to the Front Range.

Sediment is clouding the waters, they say, creating a visual smear and raising the lakebed in places, making navigation difficult for those trying to steer their boats through too-shallow reaches. Some have even seen their vessels stranded in boathouses.

Algae colonies, too, are plaguing parts of Grand Lake, as slimy green splotches spread over the water and on rocks. The sediment and algae, critics say, are linked to neighboring Shadow Mountain Reservoir and Lake Granby, components of the massive Colorado-Big Thompson Project.

The C-BT, as it's often called, moves about 230,000 acre-feet of water from the Western Slope to the northern Front Range each year, making it the largest cross-mountain water diversion in the state.

"It's really a disaster for Grand Lake," said Gordon Scheer, past president of the Three Lakes Watershed Association, a 200-member group of property owners in the Grand Lake area. "The most gorgeous natural lake in Colorado is being degraded."

Residents say the C-BT, which pulls water from Lake Granby into Shadow Mountain, then from Shadow Mountain into Grand Lake, is also pulling sediment from Shadow Mountain into Grand Lake.

The C-BT ultimately delivers that water through the Alva B. Adams Tunnel, under the Continental Divide, to a reservoir in Estes Park for distribution to northern Front Range farms and cities.

The turbidity in Grand Lake starts, residents say, with runoff from the national park, Arapaho National Forest and roads and lands undergoing development. The North Fork of the Colorado River carries the runoff to Shadow Mountain Reservoir, where sediment forms an underwater delta, a piece of submerged land stretching from the shore far into the reservoir.

"The effect upon the quality of water in Grand Lake has been devastating," Scheer wrote on behalf of the Three Lakes group in a letter to the Bureau of Reclamation last fall. The group was protesting plans by the Northern Colorado Water Conservancy District to bring even more water through the C-BT system.

"In the spring months, during normal flow (east to west), the water in Grand Lake is clear, as it was forever prior to the building of the C-BT. As the flow is reversed in July each year (with water going from Shadow Mountain into Grand Lake), the water becomes excessively turbid," Scheer added.

Because of its shallow depths, Scheer wrote, Shadow Mountain produces a "bumper crop" of aquatic weeds.

"The weeds are transported by the water flow into Grand Lake, along with substantial amounts of silt, thereby reducing the quality of life for lakeside residents and recreational users."

Other headaches

Pumping reservoir water from Lake Granby through Shadow Mountain and into Grand Lake causes other problems, residents say. It brings warmer water to Grand Lake from the shallower reservoirs - water laden with more nutrients, which exacerbates weed growth and can lead to algae blooms.

"It smells like decaying vegetable matter," said Elwin Crabtree, a longtime real estate agent in Grand Lake and current president of the Three Lakes group.

"Come July or August, you can't see a fishing lure one foot below the surface in Grand Lake."

Residents fear the problems will get worse with Northern's unfolding efforts to bring more water through its Windy Gap project. The utility could move another 30,000 acre-feet or more through the three lakes and the Adams Tunnel annually, which means water would be pumped through the lakes for longer periods of time.

"Grand Lake is going to become more and more foul, more and more of the year," Scheer said. Already, by late summer, the lake "turns green and starts to smell," he said. He blames the water imported from the other reservoirs.

In its letter to the Bureau of Reclamation, the Three Lakes group is asking that the beneficiaries of the Windy Gap project be assessed charges that would go toward dealing with the problem. Such work could include dredging and temporarily lowering water levels so the winter freeze would kill off the weeds. The group estimates the cost at $150,000 to $500,000 a year.

Officials with the Northern district say they understand residents' concerns, but say the issues need more study before blanket blame can be laid upon the operations of the C-BT project.

"I think the jury is still out," said Don Carlson, a top planner and engineer for Northern. "I don't disagree with (critics) entirely, but it's never been proven."

Carlson said some sediment from the underwater delta in Shadow Mountain could be making its way to Grand Lake, but he doubts it's a big contributor.

"(The delta) is way on the opposite end of (Shadow Mountain) reservoir," Carlson said. "It's far away."

Carlson suggests other sources, such as runoff from properties and streams around the lake, could produce sediment.

But locals are skeptical. Sarah Clements of the Grand County Water Information Network noted that sediment from the North Fork into Shadow Mountain is typically far higher, at more than 35 parts per million, than from the two inlets that flow into Grand Lake, which are around 5 parts per million.

Carlson said it's important to look at all sources of nutrients or pollutants that produce more weeds. Though wastewater discharge can be a source, pollutants also can come in the form of airborne nitrogen from cars, farms and industrial sources. One recent study said such airborne nitrogen accounted for about 20 percent of the nutrients in Grand Lake.

Furthermore, he said, the C-BT pumps water from the Windy Gap project into Lake Granby in the spring, when the water is at its highest, treated sewage is most diluted, and the seasonal population is at its lowest level, meaning the region is producing relatively little wastewater.

But mindful of mounting concerns, the Bureau of Reclamation, the U.S. Geological Survey and the Northern district are embarking on a study of all three lakes - Grand, Shadow Mountain and Granby. They hope to learn more about how nutrients and sediment move and how the interaction between the lakes affects weed growth.

Carlson said the Northern district would do what it can to manage nutrients and sediment, with the caveat that it still needs to operate its system.

"We need to continue to pump Windy Gap water," he said.

Northern officials say they've been monitoring water quality in the Three Lakes area since 1969.

"Why wouldn't we be concerned about water quality in the Three Lakes system?" said Northern's general manager, Eric Wilkinson, sitting in a conference room at the district's Berthoud headquarters. "That water is going to come over here."

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