Scrubgrass RunScrubgrass Run is a long 1st order tributary to Chartiers Creek in Allegheny County, Pennsylvania.CourseScrubgrass Run rises in Mt. Lebanon, Pennsylvania and then flows west-southwest to join Chartiers Creek across from Heidelberg.WatershedScrubgrass Run drains of area, receives about 38.5 in/year of precipitation, has a wetness index of 331.29, and is about 15% forested.