PITTSBURGH (KDKA) – It features some of most spectacular views in urban America and developers have built on just about every square inch. But, beneath the surface lies the danger.
Mount Washington sits atop abandoned coal mines, deep rock fissures and layers of red clay, all of which make it prone to the rockfalls and slides which have become an almost daily occurrence this past winter and spring. They’ve been responsible for blocking railroad tracks, shutting down McArdle Roadway and taking out other street.
It’s culminated in the largest landslide in a generation, which took out a house on Greenleaf Street.
KDKA’s Andy Sheehan: Is Mt. Washington falling down? Will it fall down around the edges?
Pat Hassett, of Pittsburgh Public Works: I would phrase it differently. I would say it’s sliding down,
Our cameras caught that sliding — a massive mound of saturated earth destroying everything in its path and oozing onto Route 51.
The scar it left reveals why. Relentless rain saturated the ground and filled abandoned mines below to capacity. All it needed was one more rainy day to set loose hundreds of thousands of gallons of gushing water to set the slide in motion.
It’s a combination of abandoned coal mines, clay formations and gravity. Add to that a record rainfall and you have a recipe for disaster that puts the whole of Mt. Washington at risk.
On the other end of the mount, William Street caved in February and residents say that’s the price of a great view.
“You have to pay to be on top of the mountain, but king of the mountain, then again king of the mountain is the first targeted to be taken out,” said Jaime Allen, William Street resident.
So what about all of those condominiums and restaurants on the edge of Grandview Avenue? This landslide raise concerns about LeMont, but it was found to be safely anchored.
Geo-technical engineer Jim Hamel said the ridge can be safely built upon given the proper investigation, engineering, construction and a lot of money.
If you want the view, be prepared to pay for it.
But, all building owners have to be aware of any shifts as they will surely come. The name Monongahela is derived from Native American word translated as “river with sliding bank.” Rockfalls and slides are a fact of life. The question is how best to deal with them?
The city wants to develop a plan of action for Mt. Washington, including keeping storm water out of the mines and vegetation to stabilize the hillsides and construction of retaining walls.
“And when they do slide make sure we have an incident management program in order to properly respond. We have the proper equipment, we have the proper coordination with the agencies,” said Hassett.
But, Hamel who has studied the mount for years, says there’s not much you can do but monitor and react.
“Just live with it. Rocks will fall, soil will slide over time as we’ve seen in the past and you clean ‘em up when they come. This is about the best you can do,” Hamel said.