Adirondack Lake Assessment Program: 2018 Report

Adirondack Watershed Institute

Corey Laxson, Elizabeth Yerger, Hunter Favreau, Sean Regalado, & Daniel Kelting

The Adirondack Lake Assessment Program (ALAP) is a research and monitoring collaboration between scientists and volunteers. Citizen science collaborations, such as ALAP, expand opportunities for scientific data collection and provide citizens with the benefit of knowing they helped advance the understanding of Adirondack lakes. ALAP is a cooperative effort between Protect the Adirondacks (PROTECT) and the Paul Smith’s College Adirondack Watershed Institute (AWI). The objectives of ALAP are to: (1) develop a long-term water quality database for Adirondack lakes and document historical trends in their limnological condition, (2) provide a repository for water quality data that multiple stakeholders can use to make informed decisions, and (3) engender lake stewardship by providing opportunities for citizens to participate in scientific monitoring. This report provides readers with appropriate background information on lake science, a regional analysis of the current water quality characteristics of Adirondack lakes, and a synthesis of current and historical water quality data for each of the participating lake. The report can be summarized in the following key points:

1. ALAP continues to be a highly successful program. Established in 1998 with only nine participating lakes, the program has grown to include up to 73 lakes, with 68 participating in 2018. Currently, the program supports 37 lakes with 15 or more years of consecutive data, and 11 lakes with 20 or more years of data. ALAP lakes are from all across the Adirondack Region, and for many of these lakes, the ALAP dataset represents the only available source for information on water quality.

2. We assessed that 65% of the participating lakes were oligotrophic in 2018. Oligotrophic lakes have low biological productivity due to relatively low nutrient availability. As a result, oligotrophic lakes tend to have high transparency, low algal abundance, and decreased probability of persistent algal blooms. We determined that 32% of the lakes were mesotrophic, an intermediate trophic status, and 3% were eutrophic, a status that is typified by low transparency and relatively high nutrient availability.

3. The average transparency of the participating lakes in 2018 ranged from an average of 1.2 meters in Otter Pond to as high as 8.7 meters in Brandreth Lake. The majority of lakes had an average transparency greater than 4 meters in depth. We found that 12% of the study lakes have exhibited a statistical decrease in transparency over time.

4. Chlorophyll-a concentration, a surrogate measure for algal productivity, ranged from 0.5 μg/L in Brandreth Lake, to as high as 17.2 μg/L in Amber Lake. Analysis of the historical data revealed that 73% of participating lakes showed no statistical change in algal productivity over time and that 27% had a decreasing trend in chlorophyll-a concentration.

5. In 2018, the average total phosphorus concentrations ranged from a low of 2.4 μg/L in Brandreth Lake to as high as 36 μg/L in Indian Lake (Franklin County). The majority of lakes (66%) had average values less than 10 μg/L.

6. The average pH values in 2018 ranged from a low 5.9 in Otter Pond to a high of to 8.6 in Augur Lake. The majority of lakes (75%) fell in the circumneutral range, defined as pH values between 6.5 and 7.5 pH units. Analysis of the historical data reveals that 25% of the lakes with long-term data have exhibited an increasing trend in pH (less acidic).

7. Wide spread use of road salt (primarily sodium chloride) over the last several decades has significantly increased the concentration of sodium and chloride in the environment. Many lakes in the Adirondacks now contain anywhere from 10 to 300 times the background concentration of chloride. The average chloride concentrations ranged from 0.3 mg/L in Otter Pond, to as high as 68 mg/L in Butternut Pond. Based on the chloride concentrations alone, we believe that roughly 72% of the participating ALAP lakes are influenced by road salt.