One of DU's first engineering projects was completed on the Moosehorn NWR, located in Downeast Maine, close to the town of Calais. The refuge was established in 1937 for the protection and management of habitats important to migratory waterfowl, especially black ducks. It is also important to other wildlife such as woodcock, where much research has been conducted on their life habits.
Many of the refuge's waterfowl impoundments were built 40 to 50 years ago and the infrastructure is beginning to fall into disrepair. One of the more productive impoundments, Howard Mill Marsh, was in need of a new water control structure to improve management capabilities. The new DU structure not only allows managers to regulate water levels on 43 acres for waterfowl but also provides for fish migration (primarily brook trout) to traditional spawning areas. The combination stop-log/fish ladder design is one of a kind.