Last year, Harmony and Zelienople boroughs, Jackson Township, the Western Butler County Authority and Butler County came together to study the Connoquenessing Creek and determine what could be done to address flooding issues.

The study examined the Connoquenessing Creek at its most downstream location in the county. Harmony lies within the floodplain of the creek, and the report noted that this is relatively unchanged since it was founded and developed by European settlers.

However, changes around the area are noted, including six bridges in the area of study: Interstate 79 north and south, two on Mercer Street, West New Castle Street and Route 19.

Construction of the Route 19 bridge is noted as having the largest impact. The northern embankment of the bridge and adjacent beams protrude into the stream.

The study examined the impact that removing the embankment would have on flooding. Under the concept, the embankment would be replaced with additional bridge deck and piers.

However, the work would affect flood levels for 10-, 50-, 100- and 500-year floods — historic flood level markers that often are used to gauge severity — by less than a foot, the study found. With permitting, design and construction as well as environmental impact mitigation, the work could cost $5 million to $10 million.

The study also looked at modifying the floodplain and floodways, which it noted have been developed, thus limiting “the opportunities for potential flood-reduction efforts.”

The area with the best chance for modification is along the Jackson Township-owned property adjacent to the Route 19 bridge. The study notes that property was historically used for three reservoirs, although it is being converted into soccer fields and a park.

Under the modifications, the most southern reservoir would remain a pond. The changes would aim to allow for a larger area for water flow, while also retaining the grading. It would remove reservoir beams, relocate utilities and regrade the area.

The result, however, indicated a decrease of less than one foot in all historic flood-event models. The unspecified cost would be significant due to the amount of work as well as the permitting required, the report notes.

Flood-control measures were also examined — such as a levee considered north of the railroad tracks in Harmony — with a focus on reducing the types of flooding the borough has seen recently.

The project would require easements or the purchase of property as well as the updating of FEMA flood maps to show floodplain changes.

All told, the project could cost $20 million to $30 million. The results of such changes would be minimal, with water surface elevations changing by one foot per each height investigated.

The study concluded that altering the Route 19 bridge and changing the floodplain at the Jackson Township reservoirs would be the best combination of projects to address flooding issues. However, the cost and length of time would be considerable.