flight plan

This map shows a rough area of the land that will be covered by a geological survey to be conducted this summer. Survey lines are separated by about 330 feet and will be modified to not cross houses, barns, other man-made structures, quarries and the paved part of the interstate.

A $281,500 study of the subsurface hydrology along Interstate 80 east of Laramie has emergency responders hoping the results will help them better prepare for potential spills of hazardous chemicals. Local officials are also hoping it will give the public a more realistic view of threats facing the Casper Aquifer, which provides about half of Laramie’s drinking water.

This week, Albany County commissioners joined the city of Laramie in funding the study, to be led by a University of Wyoming research scientist, that should provide a rough 3-D model that should provide some clarity about which individual chemical spills along I-80 have a decent likelihood of contaminating the aquifer.

In the past month, Albany County officials have been urged by advocates of greater aquifer protections to take a more hardline stance on environmental protections east of town. That pressure came after Tumbleweed Express, the only gas station that lies in the aquifer overlay zone, completed renovations this spring with the plan of re-opening. The gas station’s underground storage tanks have been cited as a top risk to the aquifer.

During a lengthy discussion at Tuesday’s Albany County Commission meeting, Commissioner Heber Richardson said he thinks certain advocates’ fears are “hyperbolic” and hopes the study will provide a better idea of the threat level the aquifer faces and offer information that allows the county to enact the best policies regarding the aquifer.

“That aquifer has had development on it for 70 years and it’s pretty dang pristine,” he said. “I think we all know there’s risk. We just don’t know how to quantify it. We don’t know if it’s so fragile that we’re in bad trouble if something happens or if there’s some kind of resilience there.”

While neither the methods behind the aerial electromagnetic study nor the potential findings are anything new for UW or hydrogeologic research, the study’s lead investigator, Brad Carr, said during the Laramie City Council’s Tuesday work session on the issue that the county and city are posed for a unique opportunity to not only know more about the aquifer, but start understanding how it behaves.

“Not that any other place in the country knows any more about their aquifer, but we could potentially start to go down the path of really understanding our aquifer, which would be very novel, believe it or not,” Carr said.

Hoping to understand the whole region in detail, Carr said the research team’s goal is to map out the area’s limestone fractures and fault zones and how the water moves within them, hoping to know what would happen if a spill or other hazard were to happen.

While he believes the study “has value,” Richardson did say he worries some water advocates will take the result of the study and “cherry-pick data points without evaluating them in their whole context because they have an agenda and they want to advance that agenda.”

“I hope the scientific community and the advocates will understand the limitations of the information as it fits into the whole picture,” he said.

Richardson said properly responding to community concerns about the aquifer has been one of the tougher challenges of being a county commissioner.

“There are some qualified scientists in Albany County who come and ask this commission for things that aren’t appropriate, and then I can’t tell the difference between science and activism,” he said.

Richardson said “careful and nuanced” approaches to aquifer protection, like the planned Pilot Hill purchase, is a good way to prevent development atop the aquifer while also avoiding costly lawsuits that might arise from infringing on people’s private property rights.

“There are some who think that public water supply should take precedence over private property rights,” Richardson said. “I can’t really entertain that, because it’s a view in the absence of limitations. Even if it’s true in idea or morality, it doesn’t jive with the legal realities. I need to find ways to protect the water without overstepping on people’s private property rights.”

Carr said the fact that the research is being driven by the university should help reduce misuse of the data.

“We are expected to be a lot more unbiased in our evaluation of things,” Carr said. “I am very much in agreement with (Richardson) that’s a lot of misinformation — especially with our aquifer. As the lead investigator on this project, my onus is to make sure everyone understands the uncertainty, the viability and the context (of this study).

“One of the most common misconceptions of our basin is that any well you drill on the east side of the Laramie Basin is a high-production well — meaning anything over 150 gallons a minute. That’s not the case. If I could drill anywhere I was legally able to do it, I guarantee that the odds would be against me finding high production wells. … There’s a reason why the railroad and the town developed where they did. Those springs are valuable,” Carr said.

While Richardson said he’s concerned the science might be misused by advocates, Commissioner Pete Gosar said he thinks “that misunderstanding (is) happening in the absence of information.”

“Every data point is helpful,” he said.

Carr said he likewise hopes the study will provide the “baseline” data that could help quell some of the “fervor around the aquifer” if the data indicates an individual spill poses little risk of aquifer contamination.

“If there was a spill and it felt like it didn’t get contained and you had to spend money on remediation and pump treatment systems, you would have an understanding of which areas are a little more threatened,” Carr said. “Now maybe nothing is, and wouldn’t that be great?”

Carr said if the study determines spills on I-80 pose a serious threat to the aquifer, he thinks there could be federal grant funding that could help fund some of the engineering controls atop the aquifer proposed for I-80 by a 2011 Trihydro study.

“Let’s say that one of the biggest results of this work is that the engineering controls proposed are really the best solution, and that no real subsurface worries exist,” Carr said. “Let’s say that there are subsurface fault zones that could take material away from the corridor, then those are the areas that we would want to further investigate down the road.”

Carr said the actual data collection should entail 3-4 days of flying a helicopter back-and-forth in areas near I-80.

The scope of work indicates that 3-D structural model of the geophysics should be available by June 2020. A year later, a groundwater flow model with 1-2 test case scenarios is planned to be presented to city and county officials.

He said his research on the Laramie Basin in recent years has revealed about 60% of subsurface water movement occurs along bedding planes. About 40% percent is diverted by fault structures, and a 3-D map of the fault structures in Telephone Canyon will give a better idea of “where it really matters” when there’s road spills.

“We can see the fractures on the road surface now, but does that extend into depth?” Carr asked. “Does it dip off at some angle that we should care about? Maybe not, and that would be great if it doesn’t.”

Vice Mayor Pat Gabriel asked during the council’s work session if this would be the “defining study” outlining fractures and fissures in the aquifer. Carr said while that would be wonderful, it’s also a little ambitious.

“It is very possible that we’ll see those faults in those data that we don’t already know of from the surface, but understanding what the known faults look like in the subsurface is really the main goal here,” Carr said during the work session. “If we didn’t have the ensuing information that we have from the Turner wells, the other wells that I’ve drilled, the study wells that turned into monitoring wells like in Imperial Heights, we would be much worse off in terms of understanding what our parameters are in terms of the structure.”

The study, depending on how high and fast the helicopter is flying, can record data from as much as 1,400 feet underground. The granite below the aquifer, Carr said, is generally at around 900 feet.

Although the city and county have an idea of some of the area’s fractures from previous studies, Carr said this summer’s data collection will help reach the subsurface fractures in otherwise undetectable areas from the surface without drilling.

While drilling would be one way to get an in-depth look at the fault zones, getting the funds and permission to drill the required amount wouldn’t be easy.

Councilman Paul Weaver, who said he was in favor of the study, did ask during the work session if there are any challenges or limitations expected from the methodology of the study, anticipating residents potentially wanting to “challenge conclusions made, especially looking at policy down the road at some point.”

Some of the more obvious limitations are weather and wind, which will impact the hoop as it dangles 150 feet below the helicopter. However, Carr said as the researchers analyze the data, peers throughout the community will be able to help “vet these data pretty heavily prior to actually totally saying we’re done.”

“We have to make sure that when data is presented, you guys understand the limitations to the best of our ability,” Carr said. “There’s no reason to also not take advantage of my other colleagues in our department (at UW), the state engineers have hydrogeologists, the (Wyoming Department of Environmental Quality) has hydrogeologists.”

Carr added the acquired information would also vary based on the researcher’s interpretation of the data once the 3-D modeling process starts taking place in 2020.

“Predictive modeling is kind of that scary slippery slope,” Carr said. “We can build a structural, geophysical model that represents the situation to the best of our data’s ability with uncertainties in our analysis, but then we can’t always for sure know that the behavior that we’re trying to predict is exactly how it would exist in real life.”

Carr said he expects to present an update to the city and county next June as the team begins the predictive modeling process.

(2) comments


Trihydro submitted an "CASPER AQUIFER PROTECTION STUDY" on April 20, 2011 (Project #: 161-002-001). What became of that? Not much. Everyone knows you have to protect your water supplies, be they lakes, streams, aquifers, or whatever- it's in the Clean Water Act. This is just more wasted monies and hand-waving- it's not novel or new. Sadly, this is just one of many cans which will be kicked down the road. Nothing will come of this or any other study because that will mean development will stop...and we certainly can't have that.

Ernest Bass

One of the alternatives offered by Trihydro in 2011 was to design and implement engineering controls to assist with containment and mitigation of hazardous materials spills. Included were three lined hazardous waste catch basins (20,000-gallon capacities each), rock lined channels to guide any spills, and a concrete shelter to store emergency cleanup equipment onsite. The total estimated cost was $230,467.19 (Table 5). If the city and county had implemented Trihydro’s recommendations we would have had some measure of protection against spills for the last eight years and many years to come. Now our bureaucrats are eager to spend at least $281,500 for a study that will provide absolutely no aquifer protection whatsoever. Why were Trihydro’s professional recommendations ignored?

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