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Bear Brook Watershed in Maine

About BBWM

The Bear Brook Watershed in Maine (BBWM) research program is centered on two small first-order adjacent forested stream watersheds in eastern Maine.  The research was begun in the mid-1980s as part of the national agenda of research to determine the effects of acid deposition on surface waters and their related watersheds.  Since then, the BBWM program of research has grown to encompass an array of scientific objectives that include acid deposition, climate change and carbon sequestration, nitrogen saturation, base cation depletion, and studies of the evolution of watershed biogeochemistry under prolonged experimental acidification.  The primary principal investigators for this research are faculty at the University of Maine, with strong collaborations with the USDA Forest Service and the US Geological Survey.  However, many other scientists and students from other institutions have and continue to work at BBWM.

Research at the BBWM site is internationally recognized for its contributions to understanding the effects of elevated nitrogen (N) and sulfur (S) deposition on forested watersheds through whole-ecosystem experimental manipulations.  Monitoring of the paired catchments began in 1987. Chemical additions of N and S, as (NH4)2SO4, were delivered bimonthly via manual and helicopter applications to the West Bear watershed beginning in November, 1989 and continued until August 2016. The adjacent untreated East Bear watershed serves as a reference.


Core Data for the Web

Precipitation and stream chemistry, along with hydrological flux, result in the core input/output fluxes of these watersheds.


The Bear Brook Watershed in Maine is a National Science Foundation Long Term Research in Environmental Biology project.

Publications from this research program can provide details of the methodology and findings.

Treatment of West Bear Brook Watershed

  • Ammonium Sulfate was used to treat the West Bear Brook Watershed.
  • West Bear Brook was treated via helicopter provided by Maine Helicopter Inc.
  • The West and East Bear Brook Watersheds are on the southeastern slope of Lead Mountain.