Eastman Lake is a focal point in the community where residents enjoy four seasons of activities in a beautiful setting. Its health depends upon good environmental practices year-round. So, hold the salt!
Members of Eastman Community Association’s (ECA) Lakes and Streams Committee work with volunteers primarily in the spring and summer months to monitor water quality and serve as Lake Hosts and Weed Watchers to help prevent, identify, and correct problems. However, maintaining a healthy lake requires a community-wide commitment year-round.
Amy Hoffman and Maureen Connelly collect a tributary water sample. / Kathy Curwen
From April to September each year, volunteers collect water samples from Eastman Lake as well as from the major tributaries that supply water to the lake. In 2016, volunteers Amy Hoffman and Maureen Connelly sampled the tributaries, including Stoney Brook and Butternut Brook that contribute 75% of the water entering the lake, and Stroing Brook, Northeast Brook, Anderson Pond Brook, Whiting Brook, Tamari Brook, and the Mill Pond Brook, all with smaller amounts of inflow. Jan Brookmeyer, Mary O’Rouke, and Alice Podesta sampled the water at the six beaches along the lake. Kathy and Robbie Stebbins generously offered their pontoon boat and expertise to assist Kathleen Curwen in testing the water from the deep spot in the lake.
Once the volunteers have collected samples, they are taken to the Volunteer Lake Assessment Program (VLAP) lab at Colby-Sawyer College in New London. After the lab finishes its work, the lab director takes some of the samples to the Concord VLAP for analysis. The VLAP labs measure a number of different parameters: E. coli (Escherichia coli), total phosphorus, chloride, conductivity, transparency, turbidity, pH, chlorophyll, and dissolved oxygen. They also provide monthly and annual reports showing Eastman’s data against median values from other New Hampshire lakes and water quality standards set by the NH Department of Environmental Services (NHDES).
Kathleen Curwen prepares to lower a sampling tube to collect water at the deep spot. / Kathy Stebbins
Eastman’s report card has been mixed. E. coli counts are consistently low and have been well within the NHDES’ standards for safe swimming at public beaches. These low counts are an indicator of good water quality.
Since E. coli is a disease-causing organism, it can be a major area of concern. To keep our E. coli counts low, homeowners must prevent their septic systems from failing and the community must prevent sewer-system malfunctions. It is also important to keep waterfowl off the beaches since geese and ducks can foul the water and raise E. coli levels.
Total phosphorus has been low, much less than the state’s median. Since phosphorus is the limiting nutrient that encourages algal blooms and sometimes toxic cyanobacteria growth, Eastman Lake’s low phosphorus levels have been good signs of the lake’s health. Sources of phosphorus include stormwater runoff, waterfowl waste, seepage from faulty septic and sewer systems, and fertilizer used on gardens and lawns.
The main area of concern for Eastman Lake’s water quality is our high conductivity readings. Conductivity is a measure of dissolved ions, such as iron, manganese and chloride, present in water. Eastman’s lake water contains iron and manganese ions because they are naturally present in bedrock throughout the watershed. There is no known remediation for these two ions. Chloride concentrations are high and have been increasing over the years. This pollutant represents a “cultural disturbance” due to human activity and is caused primarily by the use of salts in the winter on Route 10 and I-89, and on walkways, driveways, and roads in and around Eastman. Runoff and stormwater enter the groundwater and the tributaries that flow into the lake. Chronic high chloride levels can harm aquatic plants and animals.
Eastman’s Environmental Vitality staff (a/k/a maintenance staff) responsible for snow removal were certified three years ago through NHDES’ Green SnowPro Program and use a nontoxic, bio-degradable additive to help minimize the use of salt on roads. Homeowners can also do their part by eliminating or reducing winter salt use and minimizing stormwater runoff. Preventing, slowing, and dissipating overland flow of stormwater allows pollutants such as chloride to be absorbed by soil and plants before entering the lake. Homeowners with water softeners should consider preventing the discharge of salty wastewater into their septic systems. These practices can help reduce the chloride content of groundwater and tributary water that runs into the lake. Working to lower chloride levels is desirable because chronic high chloride levels can harm aquatic plants and animals. It takes more than a corps of dedicated volunteers to maintain high water quality. It takes a whole community in a year-round effort.
For more information on road salt and water quality, visit the NH Department of Environmental Services website at des. nh.gov/organization/divisions/water/wmb/was/salt-reductioninitiative/ index.htm.
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