By MICHAEL KITCH, LACONIA DAILY SUN
LACONIA — While the impact of the drought on dug wells and field crops is obvious, the conditions that began with the warm temperatures and sparse snowfall last winter and persisted through a hot, sunny, dry spring and summer have also affected lakes and ponds, where water appears relatively plentiful.
Low water levels are the clearest sign of the drought. On Wednesday, Lake Winnipesaukee stood at 504.75 feet, about 6 inches below its average level and just 4 inches above its lowest level since 1982 for this time of year. Only twice in the past 16 years has the lake fallen to lower levels at this time. The immediate effect of low water falls on marine traffic as boats are at greater risk from unmarked hazards. Last month the Sophie C ran aground in Meredith Bay and a boater posting on the Winnipesaukee Forum reported that six vessels struck rocks in "The Graveyard," a stretch of water north of Chases Point and south of Melvin Bay in Tuftonboro. Watermark Marine Systems recently advised its customers to navigate with caution.
Amy Smagula, a limnologist, or student of lakes, who manages the exotic species program at the New Hampshire Department of Environmental Services, said that the drought conditions will likely have effects on the plant and animal life of the lakes. As the lake level has fallen, more of the lake bottom is exposed to sunlight, which she said has enabled both invasive species, particularly variable milfoil, and native species of aquatic plants to grow at greater depth than usual. As a result, she said that colonies of milfoil may expand, especially in areas where they have not been effective managed and controlled.
Stormwater runoff, the primary carrier of the nutrients, particularly phosphorus, that degrade water quality has diminished with the scant rainfall. On the other hand, sluggish flows in tributaries feeding the lakes has slowed the flushing rates, or the amount of time water spends in the lake. David Neils, chief water pollution biologist at the New Hampshire Department of Environmental Services, said that while the amount of nutrients reaching the lakes has diminished they are lingering longer.
Neils said that cyanobacteria, or blue-green algae, blooms appear to be occurring more frequently as well as later in the year. But, he was quick to acknowledge that while some believe their proliferation is the result of a changing climate, there is no hard scientific evidence linking them to the drought conditions prevailing this year.
The warm water temperatures accompanying the drought, Smagula said, stress cold water species, like trout, and reduce the volume of oxygen in the lakes, which weighs on the growth of plankton and algae at the bottom of the food chain.
"For us, having to conserve water is an inconvenience," she said, "but the animal life in our lakes need water to survive."