 As of 1984 , the mean annual precipitation for the Loyalsock Creek watershed ( which Plunketts Creek is part of ) was 42 to 48 inches ( <unk> to 1219 mm ) . Pennsylvania receives the greatest amount of acid rain of any state in the United States . Because Plunketts Creek is in a sandstone and shale mountain region , it has a relatively low capacity to neutralize added acid . This makes it especially vulnerable to increased <unk> from acid rain , which poses a threat to the long term health of the plants and animals in the creek . The total <unk> ( TA ) is a measure of the capacity of water to neutralize acid , with a larger TA corresponding to a greater capacity . In 2007 , the TA of two <unk> was known : Engle Run , a 4 @.@ 9 @-@ mile ( 7 @.@ 9 km ) tributary of King Run , had a TA of 5 , and the Noon Branch , a 1 @.@ 9 @-@ mile ( 3 @.@ 1 km ) tributary of Wolf Run , had a TA of 9 . 
