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A Reclamation Story

Pittsburgh Botanic Garden is built on land that was once actively mined for coal.  In the 1920s, the area was mined through “room and pillar” mining.  In the 1940’s, the land was extensively strip mined.  In the process, soil and rock was pushed to the side, exposing the coal seam for extraction.  This process removed all vegetation and created steep “highwalls.”

Both beauty and brains define the Garden’s reclamation story. Acid mine drainage seeping from abandoned mines polluted a pond on the property: neither plants or animals could live in the pond which at pH 2.9 had an acidity similar to vinegar. The pond is now the centerpiece of the Japanese Garden, a key feature of the Asian Woodlands.

A drainable limestone bed, largely imbedded in the ground next to the pond, was filled with 450 tons of limestone donated by Carmeuse Lime and Stone Co. The draining mine water flows over the bed and the acid is neutralized. A wooden walkway was built on top of it to make it nearly invisible. When you visit, you will hardly detect the presence of the innovative passive water treatment system that brought the pond back to life.

The project at the Lotus Pond was awarded the 2014 Governor’s Award for Environmental Excellence and is a good example of effective public-private partnership. Financial partners in the pond restoration project include the PA Office of Surface Mining and the PA Department of Environmental Protection Growing Greener Program, the Allegheny County Conservation District, the Foundation for Pennsylvania Watersheds, Trout Unlimited, Colcom Foundation and an anonymous foundation.