Blue Mountain Lake Watershed Monitoring Program Project Update: 2016
Adirondack Watershed Institute
Corey Laxson, Elizabeth Yerger, & Daniel Kelting
The Blue Mountain Lake watershed has been monitored by the Adirondack Watershed Institute in one form or another for the past 24 years. In 2015, the program was changed from one that performed nutrient analysis on specific segments of two tributaries (Museum and Potter Brooks); to one that takes a more comprehensive look at the five major streams flowing into the lake. The goal of this enhanced program is to gain a better understanding of nutrient loading to the lake and the impact of road deicers. To support the upgraded program, each stream was instrumented with stage recorders and in-stream conductivity meters. This report serves as an overview of the first two years of monitoring.
The level loggers and conductivity meters installed in the streams are all performing as expected. The data has been downloaded on a regular basis since October of 2015.
Correlation between the stream height recorded by the Levelogger and discharge for the study streams is very good, with coefficient of determination values (R2) exceeding 0.87. Full development of the stage-discharge curves and conductivity-chloride relationships will take at least one more field season. Once the relationships are developed we will be able to determine stream discharge and the amount of road salt contaminants entering the lake at 30 minute intervals for the sub-watersheds.
The stream water entering Blue Mountain Lake is acidic in the early spring, and circumneutral the remainder of the field season. The streams tended to have moderate acid neutralizing ability.
The greatest export of phosphorus and nitrate comes from Museum Brook. The elevated concentrations are likely related to the permitted discharge from the Adirondack Museum. Overall, nutrient export to the lake is quite low from all of the tributaries (including Museum Brook) and is within the range of nutrient export observed for other unimpacted streams in the Adirondacks.
The eastern side of the Blue Mountain Lake watershed is significantly influenced by road salt. In general, export of sodium and chloride to the lake increases with road density in the sub watersheds.
Beaver Brook is the only sub-watershed that lacks salted roads. Our initial calculations estimate that Beaver Brook exports 0.3 kg of chloride per day to the lake. Sub-watersheds that contain salted roads export 70 to 200 times more chloride than Beaver Brook. For example, we estimate that on average Museum Brook exports 51 kg of chloride per day to the lake, which is more than all of the other streams combined.
Our loading estimates for road salt are fairly coarse because they only take into consideration a total of 11 sampling days. Data from the instream conductivity meters demonstrated that the salt loading is much higher during the spring melting period. The impacted streams also had high levels of salt during the low flow period of the summer, which indicates indicating ground water contamination. Full development of the stage discharge curves and the conductivity- chloride relationship will allow us to develop a high resolution model of salt loading to Blue Mountain Lake.
