Glade EIS delayed again to better study Poudre River

By Cherry Sokoloski
North Forty News

The environmental impact statement for the Glade Reservoir project has been delayed until at least late October, as the permitting agency tries to get a handle on whether the project will harm the Cache la Poudre River.

Chandler Peter is project director for the U.S. Army Corps of Engineers, which is overseeing the EIS process and must eventually decide whether to issue a permit for the project. He said that before the agency can make value judgements, it must have better data.

"First, we have to know the effects on the river, so we can better predict what will happen (with the project)," Peter said.

Contractors working on the EIS already submitted such a report, but Peter wasn't satisfied with the amount of detail. "I want to make sure we have the appropriate level of information," he said.

"This is an extremely large project," Peter noted, "and we were aware of the significance of potential effects." In addition, the well-being of the Poudre was one of the largest concerns of the public during the project's scoping process.

Glade is part of a proposal from the Northern Integrated Supply Project, a partnership among 15 municipalities and water districts in northern Colorado that need additional domestic water supplies. Berthoud recently pulled out of the project because of its high cost.

To satisfy the Army Corps' demand for more information, a group of experts is now looking more closely at the effects of NISP on the Poudre. The team is using a complex computerized model to see how changes in hydrology would affect geomorphology (the shape of the river channel), fish and aquatic resources, riparian vegetation and wildlife.

Changes in the streamflow, Peter explained, have a ripple effect on all these other elements. The study is especially complicated on the Poudre, he added, since it's a highly used "working river."

Peak flows a concern

The primary concern of the Army Corps is the reduction in peak river flows that would be caused by the project.

"Peak flows could be reduced 60 percent or more," Peter said, depending on the location on the river. There's less water in the Poudre downstream of Fort Collins, so flow reductions translate to larger percentages there.

The largest actual volume difference would be at the mouth of the Poudre Canyon, Peter noted. In wet years, the peak flow there averages 1,800 cubic feet per second during the month of June. That flow would be reduced by one-third in wet years, with NISP taking 600 cfs off the peak.

The Northern Colorado Water Conservancy District, which is coordinating NISP, has pointed out that the project could not take new, junior-right water off the river in below-average runoff years.

Why does peak flow matter? "It's one of the main events that allows the river to push sediments through the system," Peter said.

If there's no flushing flow, sediments build up in the stream, causing many spin-off effects. The stream channel can change, becoming wider and shallower. Vegetation can encroach into the channel, in essence "choking" the channel. Stream water becomes warmer and less supportive of cold-water species such as trout, as well as some warm-water species. There can also be vegetation changes, with plants and trees growing on the newly created sandbars.

Outside the river channel, there are also effects from lower peak flows. Marshy areas, important to water quality and to some species, can be lost. With less standing water, amphibians are adversely affected, although the change could be advantageous to reptiles, birds and mammals.

"It's not all bad," said Peter, adding that what's good for one species isn't necessarily good for another. The Corps, he noted, will have to judge "how much flow we need for ecological integrity" in and along the Poudre River.

Peter said the EIS will not go into detail on possible NISP mitigations to offset the lower peak flows. "It's up to the applicant" to develop those, he said. However, the Corps could require actions such as a periodic flushing flow, if that's determined to be necessary for the health of the river.

Once the EIS is published, Peter said, he wants feedback from the public.

NCWCD recently released a short video that explains NISP from its perspective. The video can be accessed at www.ncwcd.org/media/video.asp.