Overview

Approximately 1,200 residents of Emlenton Borough and Richland Township receive their drinking water from the Emlenton Water Treatment Plant (WTP). The raw water for this 288,000 GPD plant is sourced from the nearby Allegheny River via an underwater intake crib, dry well, and transfer pump system. The existing intake and dry well were over 100 years old and frequently clogged, requiring confined space crews to clean screens and restore flow. This system needed to be upgraded, while keeping water flowing to the WTP.

We designed a new intake system for the plant, with dual intake screens and air burst system to keep them clean and free of debris. Water piping (280 lf) from the intake screens to the dry well was also replaced. With the combined efforts of the entire project team, the upgrades were completed with minimal environmental impact to the river ecosystem, and the WTP now has a more reliable water supply.

A key issue related to permitting this project was that the Allegheny River at Emlenton is home to several Federally endangered freshwater mussel species. The construction of the intake was preceded by a salvage effort that relocated over 1,200 mussels out of the in-river construction area.

To keep the system operational during construction, two temporary floating pumps and piping were installed and operated prior to and during construction. With critical input from the project’s contractor, Reynolds Construction, a temporary causeway was built into the river to provide access to install the two 32,000 lb. concrete box foundations that house the new intake screens 200 feet out into the river. The two new screens are designed and contain coatings to prevent algae growth, muscles, and debris from clogging them. Additionally, a compressed air system was installed to periodically charge and release air bursts through the screens, to clear any silt or debris that may have settled on them.

To connect the new intakes to the dry well and compressed air system, 280 lf. of 8-inch water pipe and 1-inch air lines were installed via horizontal directional drilling. Scuba divers worked underwater to make all the final connections at the water intakes.

After the new system was finished, the stone causeway was removed, and the riverbank was restored to its original condition. Aqua and the residents can now be more confident in their water intake system’s reliability and enjoy reduced clogging and maintenance for decades to come.