State College

Rainfall leads to more Oak Hall flooding

The entrance area of Oak Hall Regional Park, along Linden Hall Road, has been having erosion issues during heavy rain, July 14, 2014.
The entrance area of Oak Hall Regional Park, along Linden Hall Road, has been having erosion issues during heavy rain, July 14, 2014. CDT photo

Sunday’s storm cut deep gouges into the paths at the Oak Hall Regional Park in College Township and brought water rushing down the access road once again, despite efforts made earlier this month to prevent future flooding.

Stormwater carried mud and rocks across Linden Hall Road toward Stan and Darlene Smith’s house, where on June 25, a downpour caused a similar slide.

“I was at the house during the heat of the rain, around 7 p.m.,” said the Smiths’ son, Bill. “When I got there, there was a good stream of water flowing down the entire road from the park.

“We saw rocks washed out onto the park road and Linden Hall Road.”

A barrier of sandbags, rocks and fencing set up in front of the house diverted the flow, protecting the Smiths’ property from the bulk of the water.

The barrier was constructed after the June 25 rock slide that environmental officials called a “50-year storm,” described by the U.S. Department of Agriculture as a rainfall event that has a 1-in-50, or 2 percent, chance of occurring in a year.

All rocks and debris from Sunday’s washout have been cleared from Linden Hall Road and the park access road.

Centre Region Council of Governments Executive Director Jim Steff walked the park Monday, pointing out damaged areas and areas where work has been done to mitigate the flow of water.

Steff said the parking lot was a particular problem area.

At the time of the first storm, all the facilities had not been installed yet, and it hadn’t yet been prepped to handle the stormwater runoff.

“When you’re dealing with a project of this magnitude, not everything gets done at the same time.”

Large sections of the park are to remain as open fields, he said. The idea was to have a pasture effect with wild grasses in the open areas, but those grasses haven’t taken root yet, causing the water to flow off in sheets.

College Township Manager Adam Brumbaugh said crews are working on lower portions of the park, getting necessary installations in place that will direct water into a holding pond.

“If we could maybe get someone from upstairs to dial down the intensity of the rain a little bit,” he said. “I mean, I like rain, but this is ridiculous.”

According to AccuWeather, 1.15 inches of rain fell Sunday. About 2.36 inches have fallen this month, compared with a normal monthly average to date of 1.47 inches.

Steff also indicated where the water had washed away the portion of a path, leading water down to an access road walkway. This washout contributed to the flooding during Sunday’s storm. He said the path will be removed completely and more silt socks will be placed uphill from the road to act as an additional barrier.

Silt socks are a filter-fabric tube usually filled with wood chips that help control the rate of flowing water.

According to a construction map by Stahl Sheaffer Engineering, the Ferguson Township-based firm consulting for Centre Region Parks and Recreation, work completed since July 3 includes a cutoff swale downhill from the parking lot with a 24-inch pipe leading to a holding basin, an increased swale at the bottom of the access road to divert water toward Spring Creek and the temporary barrier protecting the Smiths’ property.

Future contracted work will include establishing seeding to “eliminate disturbed areas throughout the site”, installation of a 15-inch pipe along a central pathway to lead to the holding basin, installation of a 15-inch pipe along the northern perimeter of the park and various swale redefinitions to prevent trail washouts.

“This is a temporary rough spot,” Steff said. “At some juncture, somebody’s going to be playing out here with their kid, sitting on a bleacher, looking out at the park, saying, ‘Wow, that is a stunning view.’ ”