We are pleased to announce that a recent project to replace water distribution and wastewater collection systems at Little Bighorn Battlefield National Monument received top honors from the Montana American Council of Engineering Companies (ACEC) 2022 Engineering Excellence Awards in the “Small Projects” category.
Little Bighorn Battlefield National Monument, a place of reflection, memorializes the fallen Lakota, Cheyenne, and Arapaho warriors and the 236 soldiers of the US Army’s 7th Cavalry who died while fighting each other in June of 1876. Also known as “Custer’s Last Stand” and “Battle of the Greasy Grass,” the Little Bighorn Battlefield holds historical significance for two cultures.
Although the site, now managed by the National Park Service (NPS), evolved over the years with new monuments and grave markers, the water and wastewater systems first installed in 1950’s to serve the facilities had not. Made up of asbestos-cement and clay pipes, the old systems were failing. Leaks, contamination, and sediment build-up frustrated NPS maintenance personnel and threatened to damage important cultural and natural resources at the site. Dry conditions and fluctuating water levels affected the availability of potable water for visitors and NPS staff.
After the NPS decided the existing systems were beyond repair, the DJ&A team was brought on to develop a rehabilitation and replacement design that would offer reliable service and reduce impacts to the historic site.
The first major challenge was to develop an accurate schematic design of how the existing systems, which had been expanded over a period of 70 years, operated and where failures were occurring. Our team completed a topographic survey and comprehensive site investigation, which included sorting through decades-old as-built documents, to create an accurate picture of present-day operations.
We worked closely with the NPS’ archaeologist and compliance personnel to evaluate several replacement options that would fulfill the Park’s desire for reliable service, while also selecting the best piping alignments and areas to minimize disturbance to a landscape with deep historic significance and archaeological artifacts.
For example, the 7th Cavalry Memorial (pictured above, right) is located a few feet from the existing underground water storage tank and its sole supply pipe. The final design preserved the supply line but added a second distribution pipe further away from the memorial.
Horizontal directional drilling protected the memorial and adjacent sensitive areas, including Lt. Col. George A. Custer’s original gravesite. Trenchless methods to replace several segments of pipe were used, which minimized the need for excavation. A final strategy included pipe bursting using a compact, mobile unit near the Park Headquarters and administration buildings. Traditional pipe bursting operations can often require a lot of equipment, but the compact unit used could complete the task while also minimizing potential disturbance.
A major success of this project was that it took only two months to construct and did not require any shutdowns of the memorial.
We were thrilled to have the project honored at this year’s Joint Engineering Conference in Helena, Montana and congratulate the NPS on this successful project.