Learning the lingo of the river

Sinuosity, Bankfull, Thalweg- it may seem like a foreign language.

But on May 14, Project Manager for Trout Unlimited, Jeff Streeter, and aquatic habitat hydrologist with the Wyoming Game and Fish (WGFD), Christina Barrineau, spent two-and-a-half hours explaining advanced river restoration terms to Platte Valley residents. Their presentation, referred to as River Restoration 101, was intended to help clarify questions the public may have about the Upper North Platte River Restoration Project.

After the meetings in December, when members of Stantec Inc. and Wildlife Hydrology presented an explanation of their operational procedures, Barrineau said she was approached by people with questions about the terminology.

"I have been asked questions about this potential project in town," Barrineau said. "Though I thought it was wonderful, and I understood what they said ... but that is because I deal with this on a daily basis. Some of the words they were talking about, I wouldn't have known what those words were either."

Though they did not comment directly to the potential North Platte River project, Streeter said the aim for the meeting was to educate the public on how rivers function and some of the terms used by the engineers.

"Those terms you are going to hear over and over again as the town and conservation district work on the project through Saratoga," he said.

Because data collection has not been completed, there is not a project plan for the Upper North Platte River Project.

In the presentation, Streeter said river restoration is meant to maintain "channel stability," which is defined as a state in which the river channel develops a stable dimension, pattern and profile, such that, over time channel features are maintained and the river system neither aggerades or degrades. When a river is stable, there is less flooding and sediment movement is at a natural state.

Though some erosion is normal in rivers, Barrineau said when there is too much erosion, it means the river itself is not stable.

When planning for a restoration project, there are several factors engineers and hydrologist need to examine, Streeter said.

"It takes a lot of data collection," he said. "We have to talk about pattern-profile, dimension, we have to talk about [water] velocity, we have to talk about size of the sediment, what is [the river] moving? How big is the sediment? Is it just moving sand because it is not a stable system, or is it taking away our banks?"

Streeter said there are more than 60 different values that needed to be accounted for in order for engineers to successfully restore a river.

"If you consider all of those gauges, you have a pretty good idea of what is going on," he said.

Due to the numerous interested parties in the Platte Valley who are concerned about the potential changes to the Upper North Platte River, Streeter recommended residents to think about the restoration like "building a house."

"First of all, you identify a need. Then maybe you scratch it out on a napkin of what you would like to see," Streeter said. "Pretty soon, you talk to an architect, then you fine tune it a little bit. Then it takes more money than you want to cost, then it takes longer than you wanted it to take. And then you realize, 'yeah, I really like living here, but I do have some compromises. Maybe I would do something a little differently next time, but I sure love it'."

Another meeting, which will include members of Stantec, will take place 1 p.m. on May 23 at the Platte Valley Community Center.

What is a "thalweg" anyways?

Bankfull - Bankfull calculation is the most important concept in river restoration. It is approximately every other year's high water. The flow is still contained within the river channel, and not spreading out onto its floodplain. This is when the river does most of the work in forming the channel. If the channel is unstable, bank erosion, and mid-channel deposition can result.

Thalweg - The deepest point of the channel; defining the channel profile.

Sinuosity -The curviness of the river channel, often used as an indicator of channel stability.

More definitions in next week's edition of the Saratoga Sun.