Day: July 28, 2025

‘We’re very proud of what we do’: #Colorado State University students help test dam safety on Halligan Reservoir model — Alex Hager (KUNC.org) #PoudreRiver

Engineering students take measurements from a scale model of the dam at Halligan Reservoir in a lab at Colorado State University in Fort Collins on July 15, 2025. Their data will help make the soon-to-be-built dam safer in the real world. Alex Hager/KUNC

Click the link to read the article on the KUNC website (Alex Hager):

July 15, 2025

This story is part of ongoing coverage of water in the West produced by KUNC and supported by the Walton Family Foundation.

If you’re going to build a new reservoir, you better be dam sure it’s safe.

Engineers at Colorado State University are doing exactly that by running tests on a giant model of a dam that will soon be built near Fort Collins. In an airy warehouse at CSU’s foothills campus, they’re sending water through a 24:1 scale mockup of the dam that will hold back an expanded Halligan Reservoir.

“It just gives us assurances on so many different levels that our design is sound, that it is going to be constructable, and that it is going to perform when it’s built, as expected,” said Darren Parkin, Halligan Water Supply Project Manager with the City of Fort Collins.

Water flows through a scale model of the area surrounding Halligan Reservoir in a lab at Colorado State University on July 15, 2025. The model was built to precisely mimic conditions at the actual reservoir. Alex Hager/KUNC

The new dam will be built to survive a one-in-ten-million year precipitation event — or 72 inches of rain — which is required to get building permits. For comparison, the devastating Spring Creek flood of 1997 was caused by 14.5 inches of rain.

Running that test, even on a dam that’s a fraction of the size of the real one, requires a huge pulse of water. It tumbles and whooshes through the manmade river with so much force that it’s hard to hear the person standing next to you.

When engineering students switch on the model, a large tank fills behind the dam. First, it spills down the stairstep-like face of the structure with a gentle trickle. Before long, it’s hitting the base as roiling whitewater. That’s exactly where most of this team’s research has been focused.

They built a series of “baffles” to slow that water down and prevent it from bashing the dam and eroding its base. They are essentially large blocks that change the speed and direction of water cascading over the dam. The engineers working on the dam say they were able to figure out precisely the best place to put those baffles, how many to install, and how far apart they should be because they were running tests on this model instead of a computer program.

A Colorado State University student monitors data at a scale model of the Halligan Reservoir dam in Fort Collins on July 15, 2025. Alex Hager/KUNC

“We can easily change things in a physical model,” said Jeff Ellis, who manages the hydraulics lab where the model is housed. “We can move things by an inch and just keep on retesting, and it’s really optimizing performance.”

The City of Fort Collins is nearing construction on the dam, which will enable them to expand Halligan Reservoir’s storage capacity. City officials say that it’s necessary to supply water to the growing city in the future. Work on the new dam, about 25 miles northwest of Fort Collins, is expected to start in early 2027 and finish in late 2029 or early 2030.

Ellis said the project serves another function, too. It’s giving engineering students a new kind of experience.

“It’s super rewarding,” he said. “A lot of time in class, you’re doing a lot of theoretical work, it’s not hands-on. Where this, they’re actually doing design and they’re helping solve these real world problems.”

Water tumbles over a model of the Halligan Reservoir dam in a lab at Colorado State University in Fort Collins on July 15, 2025. Students tested different baffles at the base of the dam to help prevent erosion during times of excess flow. Alex Hager/KUNC

Students helped build the intricate model, which is shaped exactly like the area around Halligan Reservoir, and they operate the data-gathering equipment that helps engineers form conclusions from their testing. Catherine Lambert, an undergraduate senior studying Environmental Engineering, said the experience was fun and exciting, but would also help prepare her for a career.

“It’s really cool to see all of our hard work actually translate into the real world,” she said, “We’re very proud of what we do here.”

Halligan Reservoir aerial credit: City of Fort Collins

Dry and getting drier — AlamosaCitizen.com #SanLuisValley

Unprecedented continental drying, shrinking freshwater availability, and increasing land contributions to sea level rise. Credit: Science Advances

From the Alamosa Citizen Monday Briefing:

This report by Science.org and this explainer from the investigative nonprofit ProPublica on the drying climate puts the San Luis Valley squarely in the camp of a mega-drought region that is dry and getting drier. It also signals the uphill battle irrigators in the San Luis Valley and the Upper Rio Grande face as they implement their own practices to reduce groundwater pumping and efforts to recharge the aquifers of the Valley; few other regions facing the same quandary of overpumping and depleting aquifers have committed to the same. In this case, there’s a lot others can learn from the Valley’s way of addressing its drying problem.

Click the link to access the research article on the Science Advances website (HRISHIKESH A. CHANDANPURKAR, JAMES S. FAMIGLIETTI, KAUSHIK GOPALAN, DAVID N. WIESE, YOSHIHIDE WADA, KAORU KAKINUMA, JOHN T. REAGER, and FAN ZHANG). Here’s the abstract:

Changes in terrestrial water storage (TWS) are a critical indicator of freshwater availability. We use NASA GRACE/GRACE-FO data to show that the continents have undergone unprecedented TWS loss since 2002. Areas experiencing drying increased by twice the size of California annually, creating “mega-drying” regions across the Northern Hemisphere. While most of the world’s dry/wet areas continue to get drier/wetter, dry areas are now drying faster than wet areas are wetting. Changes in TWS are driven by high-latitude water losses, intense Central American/European droughts, and groundwater depletion, which accounts for 68% of TWS loss over non-glaciated continental regions. “Continental drying” is having profound global impacts. Since 2002, 75% of the population lives in 101 countries that have been losing freshwater water. Furthermore, the continents now contribute more freshwater to sea level rise than the ice sheets, and drying regions now contribute more than land glaciers and ice caps. Urgent action is required to prepare for the major impacts of results presented.