Penobscot and Piscataquis River Data Reports 

Data reports are currently available for 1997's sampling of the Penobscot and Piscataquis Rivers. This effort was lead by Dave Miller and Paul Mitnik of DEA assisted by Jim Sohns and Clarissa Trasko of EMRO, of L&W Bureau, and involved various stakeholders who participated in the planning and actual field sampling of the project. Some of the participants who assisted DEP included the Penobscot Indian Nation, USEPA, Great Northern Paper, Lincoln Pulp and Paper, Champion International Corp., Guilford- Sangerville Sanitary District, Guilford Industries and a coalition of point source dischargers named the Penobscot River Basin Dischargers Council (PRBDC). For the Penobscot project, 103 miles of river were covered from Millinocket to Bucksport. The Piscataquis project covered 23 miles of river from Guilford to Milo.

Parameters sampled included dissolved oxygen, temperature, nutrients, chlorophyll a, secchi depth, and ultimate BOD. The sampling was undertaken to check compliance with dissolved oxygen standards specified by water quality classification and for calibrating a water quality model. The water quality model is used to predict worse case dissolved oxygen levels at conditions of low river flow and high water temperature; and necessary pollution load reductions, if appropriate.

All dissolved oxygen readings on the Penobscot River either met or exceeded minimum classification criteria at all sampling locations except North Lincoln where minor violations (< 0.3 ppm) occurred on one day of the sampling. When readings are compared from the last major sampling effort in the early to mid 1980's, it can be concluded that water quality of the Penobscot is continuing to improve. In fact, readings for two class C segments (confluence Cambolasse Stream to confluence Piscataquis 15 miles; and Maine Central Railroad bridge in Bangor to confluence Reed's Brook - 6 miles) met class B D.O. standards except on one day above the West Enfield dam when D.O. readings (6.8 ppm) were within 0.2 ppm of the minimum B standard of 7 ppm. Both of these segment are currently being considered for upgrades in classification to B.

The Piscataquis River dissolved oxygen readings indicate that minimum classification criteria were met for a class C segment in Guilford, but not met for a class B segments at many locations in the Dover and Milo areas. There is not enough historical data here to make any conclusions about trends.

Address for comments:  Rob Mohlar 207-287-4301, Maine Department of Environmental Protection, State House Station 17, Augusta, ME  04333-0017.