Using data collected over the past 15 years, DRBC, along with state and federal monitoring agencies, has improved the scientific record of background water quality conditions known as Existing Water Quality (EWQ) for Commission Special Protection Waters (SPW). SPW covers the entire non-tidal Delaware River and the watershed that drains to it.

Now that EWQ has been defined, DRBC compiled these water quality data into a technical document entitled Existing Water Quality Atlas of the Delaware River Special Protection Waters. This report summarizes EWQ for 85 locations on the upper, middle and lower Delaware River SPW:

• 28 Interstate Control Point (ICP) locations on the Delaware River and West Branch Delaware River
  
  
• 57 Boundary Control Point (BCP) locations in tributary watersheds:
  • 11 sites in New York
  • 30 sites in Pennsylvania
  • 16 sites in New Jersey

The primary use of these baseline site-specific data is to be able to assess measurable water quality changes in the river over time so that SPW program effectiveness can be measured. An assessment of the lower Delaware was completed from 2009-2011, and the report was published in August 2016. The next assessment is currently underway (2023-2025).

Existing Water Quality Atlas of the Delaware River Special Protection Waters, September 2016 (pdf 19 MB; includes bookmarks)

Report Sections:

• Introduction (pdf 8.75 MB)
  
  
• Upper Delaware: West Branch, Delaware River to Neversink River, N.Y. (pdf 8.3 MB; includes bookmarks)
  
  
• Middle Delaware: Delaware Water Gap Northern Boundary to Slateford Creek, Pa. (pdf 5.7 MB; includes bookmarks)
  
  
• Lower Delaware: Portland, Pa. to Trenton, N.J. (pdf 7.7 MB; includes bookmarks)