As you head upstream, quality diminishes as seen in the increased amounts of Class III organisms or complete absence of organisms. The west branch is slightly worse than the main branch. Total Macro-invertebrates More organisms are found in the summer and fall. Warmer water causes more activity and reproduction than in cold water. Also more food is available.
Weather is the direct result for changes in depth, width, velocity, and discharge.
The greater the amount of precipitation, the greater the runoff, which as an end result is to cause an increase in these factors. Only possible cause is malfunction of Schuylkill Haven Sewage Treatment Plant, too many suspended solids in the effluent.