About 100 people were evacuated Monday in Derry Borough and Township to two shelters after an out-of-use dam began filling quickly with storm water, according to Westmoreland County Emergency Management Director Bud Mertz.
The Lower Ridge Dam, off Twin Maples Road, was 2 feet below evacuation level Monday morning when officials noticed some seepage in the wall of the dam, Mertz said.
The dam is owned by Derry Borough’s municipal authority, which activated its emergency action plan around 11 a.m. on Monday, according to Bradenville Volunteer Fire Department officials.
Once water levels drop to a safe level, the dam will be inspected by a professional engineer to determine if it is safe for residents to return to their homes, fire officials said.
The Lower Ridge Dam has been down for maintenance since June 14 when a drain line was damaged, Bradenville fire officials said.
“However, the excessive rainfall caused the off-line dam to rapidly fill with water, and it (created) pressure on the already-damaged drain line, (which caused) water to seep from the toe of the dam,” Bradenville officials posted on the fire department’s website.
Residents and others are cautioned to avoid the area downstream of the dam in the McGee Run Stream valley.
Evacuation centers were set up at Derry Area High School and St. Joseph’s Parish, however Red Cross Marketing and Communications Director Dan Tobin said the high-school center had begun the process of closing.
Renatta Signorini is a Tribune-Review staff writer. You can contact Renatta at 724-837-5374, [email protected] or via Twitter @byrenatta. Patrick Varine is a Tribune-Review staff writer. Reach him at 724-850-2862, [email protected] or @MurrysvilleStar.