Reston Association to spend more on lake management this year

The Reston Association plans to spend more on lake management in 2021 than in previous years.

Lake Anne and Lake Thoreau suffered from constant algae blooms and overgrowth of invasive hydrilla in 2020, according to an RA community discussion last week about the lakes.

To manage those rather typical lake-related issues, the plan is to take a more “proactive” mitigation strategy, but that requires increasing the lake management budget, a possibility that was first discussed last fall in relation to a potentially toxic algae bloom that emerged in Lake Thoreau over the summer.

However, the investment is planning to be substantially more than initially thought.

In 2020, RA spent $17,000 for monitoring and treating lakes. In 2021, the plan is to spend about three times more money — nearly $52,000.

As stated at the March 31 meeting, this is largely due to Lake Thoreau.

Besides algae, Reston’s deepest lake also suffers from overgrowth of hydrilla, an aggressive, invasive aquatic plant that crowds out native species and impedes boating and fish habitats.

“Hydrilla is a big concern in Lake Thoreau,” said Bill Kirkpatrick of Aquatic Environment Consultants, which RA hired to manage the lakes. “Hydrilla grew late in the year, and the treatment was done on an emergency basis. We’ve revisited this and rethought the process.”

The plan is to start treatment early in the growth stage with a low, multiple-dose application of herbicide that is released slowly through clay pellets dropped to the bottom of the lake.

“It’s kinda like taking antibiotics,” Kirkpatrick said. “You don’t take all of it at once…You split it up to keep a certain concentration in your body.”

While this is a more expensive and time consuming way of treating the hydrilla, the hope is that it lasts much longer.

“It should suppress the growth and it never reaches that big die-off phase,” Kirkpatrick said.

While the hydrilla treatment will cost about $19,000 in 2021, the consultant believes that, if it is successful, no further treatment will be needed in 2022 or, perhaps, for several years beyond.

Starting in May, both Lake Thoreau and Lake Anne will be treated with low-dose algeasized concentrations on a monthly basis through September.

“The goal is to control the noxious algaes and allow the beneficial algaes to exist,” Kirkpatrick said.

Aquatic Environment Consultants plans to manage algae in this manner going forward, and the cost of algae treatment in 2022 is expected to remain the same.

All in all, it’s currently being estimated that the budget for lake management in 2022 will be $29,471 — about $22,000 less than RA anticipates spending in 2021.

The budget also includes funds to monitor lake water quality and to manage alligator weed, water primrose, and water lilies on Lake Newport.

The community discussion covered several other lake-related topics as well, including restocking the carp population, a new fishing line recycling program, and managing the Canadian geese population by tracking nests, counting geese, and potentially addling eggs.

“They cause traffic disturbances, they cause damage to people’s property, and they can put a huge amount of nutrients in the lakes, which can cause some of those algae blooms,” RA Watershed Manager Bill Peterson said. “We are not trying to eradicate the geese population, just trying to keep it down to an acceptable level.”

In recent months, the Reston Association has increased the assessment fee by $10, and as noted at the meeting, the boat mooring rate has also gone up.