You Can Help Prevent Blooms
Cyanobacteria, formerly known as blue-green algae, represent the earliest known form of life on earth. They are naturally occurring organisms that can grow in abundance to form blooms when there is the right combination of sunlight, warm water, and excess nutrients in a waterbody. Cyanobacteria can also produce cyanotoxins that can be harmful to both pets and humans.
Over the past 20 years or so, Webster Lake has experienced cyanobacteria blooms in the spring and fall when conditions are just right for a “bloom”, allowing the cyanobacteria to materialize into a green pollen-like substance in the water column and a blue-green scum on the surface. These conditions are: loss of stratification of the lake (meaning the water temperature is more even throughout the layers from top to bottom); the presence of the bacteria in the lake bed; and plenty of nutrients from outside sources to feed on.
In the early 2000s, the City of Franklin obtained a grant to do a watershed study to identify where these nutrients were originating. The majority were coming from what is known as external loading, which means that these nutrients are introduced from outside the lake. Several major sources were identified and remediated. However, external loading still exists—and you can help curtail the inflow. How? Here are several external loading sources and remedies:
- Fertilizers—fertilizers are nutrient-rich phosphorus-based chemicals that serve as a food source for cyanobacteria and are a major threat. Do not apply fertilizers within 25 feet of the shoreline.
- Run Off—Rain and storm-water runoff carry nutrients to the lake. Inspect your property and remediate any areas of erosion and water runoff.
- Septic Systems—Have your septic system pumped and inspected regularly. Systems with leaching beds not functioning properly are a major source of nutrient loading.
- Pet waste—pick it up!
- Phosphorus-free—use phosphorus-free soaps for laundry, bathing, and sinks in your residence.
- Storm drains—Storm drains on lakeside roads are direct conduits to the lake. Do not wash your car or perform cleaning operations where contaminants may find their way to the storm drain.
- Report any signs of green surface scum to NHDES using the Bloom Report Form on the NHDES Cyanobacteria Harmful Algal Blooms pages.
While the internal loading of the lake will continue, we can reduce the external loading by being vigilant in looking out and fixing nutrient loading issues. By doing this we will see dwindling severity and lessening of cyanobacteria blooms.