July 28: Engineer Research and Development Center (full link below)
Researchers from the U.S. Army Engineer Research and Development Center (ERDC) have partnered with the U.S. Army Corps of Engineers (USACE) Pittsburgh District for a study focused on replacing auxiliary locks at three sites along the Upper Ohio River — Montgomery Lock, Emsworth Lock and Dashields Lock.
Improving and maintaining the navigability of our nation's waterways is a top priority for USACE and has been at the heart of the organization’s civil works mission for almost 200 years. Installing dams along waterways is beneficial for navigation, flood risk management, fish and wildlife conservation and recreation. However, once a dam is installed, there must be a way for vessel traffic to move from one side to the other — that’s what the locks do.
Currently, the existing auxiliary locks at Montgomery, Emsworth and Dashields are much smaller than the main locks. Using numerical and physical modeling, the research team is evaluating the best designs to replace the smaller ones with much larger structures.
“We started on Montgomery with the full expectation that we’re going to be doing the same kind of studies for Emsworth and Dashields,” said Allen Hammack, research mechanical engineer for the ERDC’s Coastal and Hydraulics Laboratory (CHL). “We began model design in October 2020 and started our initial testing in May 2021. We completed that late last year and began testing the current design in March. We should be done with that soon, and then we will move on to the other two locks.”
“Right now, everything looks good, and I think a lot of that good performance is based on the numerical modeling that Pittsburgh District did before we came to the physical models,” he continued. “They ran both a navigation model and a filling and emptying system model, and the numerical modeling helped answer some of the questions we had for the design.”
At the ERDC, two physical models have been constructed to test the new designs as well — a navigation approach model and a filling and emptying system model. Everything was built onsite save for a few specific commercially available instruments.
“The two models are inherently related,” said Hammack. “They both feed into the same overall lock design.”
The navigation approach model is a 1:100 scale model that includes a couple of miles upstream and downstream of the lock and dam. The model is used to evaluate guard wall lengths in relation to navigation conditions and how well — and safely — a vessel can navigate into the lock on both sides.
“Ryan Hoben, a research civil engineer with ERDC-CHL, is the team lead for the navigation approach model,” said Hammack. “He is also evaluating the navigation conditions during construction, or construction sequencing, because it’s going to take a few years. Three to five years is typical on this type of construction effort.”
With the filling and emptying system model, the team is taking a closer look at the details inside the lock, like the intakes, the culvert layout, the outlets and valve operation times.
“We’re measuring the hydraulic forces acting on the vessel,” said Hammack. “We’re measuring filling and emptying times and looking at general flow behavior — that’s where we’re releasing dye to watch how the jets from the culverts are issuing into the culverts and out through the ports. How are those interacting with one another? We’re trying to improve the design there.”
“It is far more cost-effective for us to analyze the performance of something in a scaled model and tweak the model than it is to tweak the full-size facility after it is constructed,” said Steve Fritz, mega projects program manager for the Pittsburgh District.
“Because the new locks are going to be on the riverside of the existing structure, we’re constrained on how we can introduce water and remove water from the system,” said Hammack. “We concluded that we want to do what’s called an in-chamber longitudinal system design, which takes the two culverts out of the walls and brings them into the chamber and puts them on the floor. That’s why we’re doing the physical model study. We’ve got unique or uncommon restrictions on the intake and outlet placement that is very site-specific.”
“The physical modeling and analysis that ERDC provided for this project gave us a lot of confidence in our design,” said Chris Dening, Pittsburgh District’s Upper Ohio Navigation project manager. “There’s nothing like physical modeling when it comes to ensuring an investment in major infrastructure, like a new lock chamber, will function as intended.”
The system of harbor channels and waterways developed and maintained by the USACE is integral to the nation’s transportation system and essential in maintaining economic competitiveness and national security.
“In our country, we see trucks on the road, and we know they are carrying stuff,” said Hammack. “We know we have airplanes moving stuff around, but so much more is moved through our waterways that people don’t see unless they live or work near those waterways. Coal, rock, grain and chemicals — things we couldn’t put on our roadways due to congestion or costs. Navigation is not only important, but vital to our way of life.”