Something in the Water
By Steve Chaconas
Lake Anna anglers have been wary of the blue green algae that’s been spreading over the 13,000 acre lake, one of the largest freshwater inland reservoirs in Virginia. For the last four summers, swimming has been restricted as Cyanobacteria, a harmful algae that causes skin rashes and stomach illnesses, dangerous for children and animals, has been covering shallow coves of the recreational lake. The Department of Health has issued notices to steer clear of contact with the blooms, warning swimmers to “avoid discolored water or scums that are green or blueish-green because they are more likely to contain toxins.”
The Lake Anna Civic Association (LACA) is launching a pilot Cyanobacteria Mitigation Program. It addresses causes of the harmful algae and the elimination of it. Long-term solutions are based on prevention and that points to reducing nutrients, primarily phosphorus and nitrogen, entering from the watershed or from deposited sediments. A mix of runoff input from urban or agricultural areas is a big challenge as Anna has 200 miles of shoreline. Runoff from nearby farms and homes overloads the lake with nutrients allowing algae to flourish. In addition to the effects on humans and pets, algae can cloud the water creating more turbidity blocking light to other aquatic vegetation.
To address nutrients flowing into the lake, experts have created a plan to reduce nutrient loading in each basin and provide substantial water quality improvement, especially in sections where nutrients remain high. Watershed Management Best Management Practices (BMP) include street sweeping, catch basin cleaning, buffer strips, and filtration systems. Hydrogen peroxide-based treatments are also considered a BMP. Chemical treatments are fairly low cost and can offer immediate solutions to treat visible outbreaks, but still can be up to $1500 per acre and also used for spot treatment of outbreaks. Estimated costs per tributary, $200,000 to $500,000.
Studies have focused on areas with average depths of 9ft because shallow lake areas tend to have greater rates of nutrients suspended with wind, current and boating activity. LACA identified a section of Lake Anna as not meeting state water quality standards due to the harmful algae blooms. The algae blooms have spread mostly in the upper areas of the North Anna and Pamunkey branches, with smaller outbreaks in the middle and lower areas of the branches. Lots of testing has taken place and many feel now is the time for action. This initial pilot program will use BlueGreen Water Technologies’ granular treatment which is supposed to selectively target and eliminate harmful cyanobacteria/algae without harming other life forms or leaving any chemical trace in the water. Essentially, this releases hydrogen peroxide which is an algicide and eventually breaks down harmlessly into water and oxygen. It has been used in Israel, Russia, China, and South Africa and has been applied in Florida, Georgia, California, and Utah. The treatment is being reviewed by the Virginia Department of Agriculture and Consumer Services. Treatment needs to be applied before the blooms form, or 10 times more treatment will be needed.
Other cost-effective, natural, and long-term solutions include promoting native shoreline vegetation to improve water clarity, stabilize shorelines, and reduce nutrients. Plant growth levels of desired species are being established in areas where they would be effective.
Planting would occur in small plot areas in a variety of substrates to determine the best to minimize losses. Expected planting costs would be approximately $25,000 – $50,000 per surface acre, depending on planting density and species. Large common carp populations take a toll on subaquatic vegetation. Removing carp can help these natural vegetation filters. Carp also increase turbidity during spawning periods.
This algae will be tough and expensive to wipe out as Cyanobacteria survive well in high water temperatures, adapt to low light conditions, and are able to regulate their buoyancy in the water column to obtain nutrients from bottom to surface waters. Fingers of the lake are likely acting as nutrient filters for incoming watershed, meaning the primary productivity of plants and algae decreases downstream to the outflow at the dam. Unfortunately, algae uses the nutrients before they reach the water-clearing submerged vegetation. However, promoting growth of all vegetation in the lake’s fingers upstream could provide substantial water quality improvements.
It’s been reported that the cost of the first treatment is $100,000 and about $300,000 annually to prevent the blooms. LACA has launched a campaign “Kick the HAB”, referencing Harmful Algae Booms, to raise money. Attempting to kill off the algae blooms before they form is not a permanent solution. A complete, more intensive approach to eradicating algae blooms is needed, at an estimated $200 million cost and could take decades to complete.
Potomac River Bassing in August
Get out early before it gets too hot! Fish thick grass with hollow bodied frogs and punching. Use 60 pound test Gamma Torque braid. Same line with a ¾-1.5 ounce tungsten weight to punch through matted grass with Texas rigged soft plastics. These techniques are best when it’s hot and sunny. For frogs, cover water over grass to locate bass for the punching method. Punch through loose grass and sticks, etc. floating around thick mats.
Early in the day or under low tide or cloudy conditions, use walking baits and poppers, on 30 pound test Torque braid around edges of grass, docks, or riprap. Vary speeds depending on water clarity, faster in clear, slower in stained water.
Shallow diving crankbaits cover water tied to 14 pound test Gamma Edge fluorocarbon. Another bait to use it a big bodied, buoyant crankbait like the Lucky Craft BDS 4. Contacting grass is key for both of these. Crank down to the grass and snap free, then pause and repeat.
Jigs work…pitching, swimming and bladed jigs in craw patterns or black/blue pattern…in grass and around docks. Use either Gamma braid or fluorocarbon line. Heavy drop shot works around cover and in grass.
Author Capt. Steve Chaconas is Potomac bass fishing guide. Potomac River reports: nationalbass.com. Check out YouTube page, NationalBassGuide.