How healthy is the Poudre River? — The Fort Collins Coloradoan

Map of the Northern Integrated Supply Project via Northern Water
Map of the Northern Integrated Supply Project via Northern Water

From the Fort Collins Coloradoan (Jacey Marmaduke):

Citing low flows in the winter and insufficient flushing flows in the spring, river experts give the health of the Cache la Poudre River moderate marks. Ken Kehmeier, senior fishery biologist at Colorado Parks and Wildlife, gives it a “C-plus.” Ellen Wohl, a Colorado State University geosciences professor, prefers “needs improvement.”

“It’s not going to catch on fire like the Cuyahoga River did in the ‘60s, but it’s a very different river than it was in say, 1858,” she said. “I’d never give up on the Poudre. It’s ailing in health, but it can recover, and it’s not anywhere near being done.”

What does the future hold for the Poudre? That interpretation depends a lot on who you ask. It also will depend on how Northern Colorado leaders respond to potential obstacles raised by climate change, urban development and the Northern Integrated Supply Project.

Climate change

Colorado’s in a weird spot when it comes to climate predictions.

While it’s clear temperatures will increase — they already have — there’s no consensus on whether climate change will bring more, less or the same precipitation to Colorado.

Regardless, warmer temperatures are an issue for the Poudre and its aquatic life and water users. The Poudre is fed primarily by mountain snowmelt, and as Colorado’s average temperatures rise, the spring pulse — the onset of higher spring flows fed by snowmelt — will come earlier than usual.

John Stokes, Fort Collins Natural Areas director, said he already sees it happening on the Poudre.

“Our snowmelt is getting earlier and earlier. It’s probably about two weeks earlier now than it used to be,” Stokes said. “As that accelerates, what does that do to our storage in the mountains, which is snow and ice? We rely on the timing of that storage.”

Not everybody agrees with Stokes. Poudre River Commissioner Mark Simpson said flows have varied so much during the last 50 years that he doesn’t see a shift in the peak, which generally occurs around the first week of June.

[Ellen Wohl] said she hasn’t necessarily noticed that trend on the Poudre — the system is so meticulously managed that it can be hard to tell when high flows are the work of Mother Nature or water engineers, she added…

Development

The biggest protection — literally — is a development buffer zone of 300 feet on either side of the river through most of Fort Collins. That’s nearly the length of a football field. The buffer zone, which is enhanced by city ownership of most of the land along the river, quells any fears that the Poudre will one day turn into a built-out river walk. It also mitigates flood risk.

“Maybe In a perfect world we would have had quarter- or half-mile setbacks from the river,” Stokes said. “This river used to go all over the place. It would change its course frequently. But now, it’s pretty much locked into its location because of the way we’ve developed around it.”

[…]

NISP

Proponents say Northern Colorado needed NISP yesterday. Opponents argue that the project will irreversibly damage the river that has long been a lifeblood for the region.

Reservoirs are “exhibit A” for the future of Western water, said Brian Werner, spokesman for NISP initiator Northern Water.

“We’re going to need reservoirs for the next 200 years,” he said. “We’ve got to figure out where to store that water in the wet times so you can use it in the dry times.”

It’s easy to reduce NISP to a lengthy timeline and a lot of bureaucratic jargon, but it’s more than that. The project has become symbolic of a major question about the future of water use: How do we meet the water needs of staggering population growth without harming our rivers?

NISP would divert from the Poudre during peak springtime flows. That causes concern for many because the river needs flushing flows to thrive.

“As the water moves, it has the power to carry things,” Kehmeier said. “When you take that power away from it, then all those sediment pieces drop out and deposit on the (river bed).”

Sediment buildup can make the river dirtier, smellier and fill it with algae and non-native, potentially invasive, species.

Wohl is skeptical of NISP, partially because of the flushing flows issue and partially because the river already lacks a natural flow regime.

Downstream, “the volume of the water isn’t really natural,” Wohl said. “That has a cascade of effects. If you change the amount of water in a river, you change the energy available for processes like picking up and moving sediment, you change the shape and size of the river, you change the habitat available for organisms.”

But it’s possible for NISP to coexist with a healthy river if Northern Water plans accordingly, Kehmeier said.

“With these flushing flows, you’re looking for a recurrence interval,” he said. “Every one-and-a-half to two years, you should have a flow that’s considered bank-full.”

NISP could also boost historically low winter flows on the Poudre by releasing reservoir water into the river during dry times, Kehmeier said.

“From a fisheries standpoint, the Poudre is as limited by low flows, probably more so, than it is by flushing flows,” he said. “Fish don’t survive very well without water.”

Wintertime releases are a component of Northern Water’s recently unveiled conveyance refinement proposal, which is basically a plan to run 14,000 acre feet of the diverted water through most of the Poudre’s stretch in Fort Collins. The move was partially intended to address some of the city of Fort Collins’ issues with NISP, but the city, which is not a NISP member, has yet to respond to the new plan…

What’s next for NISP:

The Army Corps of Engineers says it will release a final environmental impact statement for the project sometime in 2017. After that must come a 401 permit and a record of decision, which NISP opposition group Save the Poudre Executive Director Gary Wockner anticipates will come in 2019. If the record of decision approves the project, Save the Poudre is prepared to challenge it in court, setting off a legal battle which could take years.

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