Blue Mountain Lake 2013 Report: Chemistry of Museum and Potter Brooks
Adirondack Watershed Institute
Daniel Kelting & Corey Laxson
A tributary monitoring program was initiated in the 1990s within the Blue Mountain Lake watershed. The main purpose of this monitoring program is to identify and understand factors that influence the water quality of the lake itself. Two tributaries were monitored in 2013, Museum Brook and Potter Brook. A grab sample of stream water was obtained at each of 11 stream monitoring stations (4 along Museum Brook and 7 along Potter Brook) at five separate times roughly one month apart spanning May to September. Highlights from this report include:
Total phosphorus and nitrate concentrations were higher at downstream locations in Museum Brook and were higher at the outlet than the majority of observations from least impacted streams in other regions of the Adirondacks.
There were no trends in total phosphorus or nitrate concentrations moving downstream in Potter Brook. Total phosphorus concentrations were generally within the range of concentrations observed for least-impacted streams in other regions of the Adirondacks, while nitrate concentrations were generally higher than the majority of observations from these least impacted streams.
Total phosphorus load estimates averaged 0.12kg/ha/yr for Museum Brook and 0.11kg/ha/yr for Potter Brook, with no trends apparent in the estimates. Load estimates for both tributaries were within the range of total phosphorus loads reported for a least impacted stream in the Adirondacks, but the estimates for Museum Brook and Potter Brook were highly variable
Fecal coliform counts exceeded various thresholds for samples collected from both tributaries, with thresholds exceeded at both least impacted and impacted sampling locations.
Sodium and chloride concentrations and conductivity at the outlets of Museum Brook and Potter Brook were substantially higher than values for least impacted streams in other regions of the Adirondacks. Values for these analytes upstream of paved roads in Museum Brook and Potter Brook were within the range of values for least impacted streams in other regions of the Adirondacks.
Elevated total phosphorus and nitrate concentrations at downstream locations in Museum Brook were likely from pollutant inputs. Though total phosphorus loading estimates for Museum Brook suggested that loads were still within expected values for least impacted streams, high variation reduced our confidence in these estimates as well as in those for Potter Brook. The lack of downstream trends in total phosphorus and nitrate concentrations in Potter Brook suggested that development has not had measureable impacts on nutrient inputs to this stream. The substantially elevated sodium and chloride concentrations observed in both streams below paved roads were clearly from road salting, which has had a significant impact on the chemistry of both streams and the lake.
As was stated previously, the main purpose of this monitoring program is to identify and understand factors that influence the water quality of the lake itself. Yet, Museum Brook and Potter Brook collectively drain only 20% of the total watershed area of Blue Mountain Lake and thus most of the watershed is not currently monitored. Thus, we recommend expanding the stream monitoring program to include all major streams. We recommend further that the outlets of each stream be instrumented with conductivity and stage sensors to obtain the high resolution data necessary to observe impacts and to estimate nutrient and salt loads with greater confidence.
