Algae and Nutrient Control in Ponds | Weed & Algae Control Case Study
Keeping your lakes, ponds and fisheries ecologically balanced and looking beautiful isn’t a one-time job. It requires consistent care by highly trained lake management professionals. If you wait until a problem reveals itself to take action, chances are you’ll always be playing catch-up, which is why SOLitude believes in proactive management plans to help keep water quality issues from occurring.
Below are case studies highlighting a few of our success stories involving algae and pond weed control.
Location: Lewes, DE
This property is a subdivision just outside Lewes in Sussex County, Delaware, encompassing 35 acres which include 162 lots of ½ to 3 acres each. The landscape of this private community was developed in 2007. It is made up of mostly single-family homes and includes a community pool, pool house, and park. The park is approximately eight acres in size and contains a fully enclosed four-acre surface pond. The pond was created in 1878 during the construction of the Junction Breakwater Railroad. The tracks and rail bed were removed to create the Junction-Breakwater Trail, with the trailhead at the southern end of the pond and the northern unused bed forming the eastern boundary of the park bordering the community. The subdivision uses the swale system of stormwater management. The entire upper half of the development surface water and groundwater flows into a proximal catchment area then into the pond, exiting into the nearby marsh and watershed.
Scope of Work:
In the summer of 2015, the impaired watershed (the pond) sustained a compound algae bloom and an extensive fish kill following a natural algae die-off and subsequent drop in dissolved oxygen (<1.5). The water quality has suffered and the algae bloom was caused by an increase in organic nutrients with high phosphate levels from large trees having fallen into the pond and leaves blowing into the pond both caused by the destabilized and eroded banks.
The HOA turned to SOLitude Lake Management for short and long-term solutions based on their budget, contracted with SOLitude for one year of algaecide treatments with a plan to develop a long-term nutrient remediation solution. The goal of the short-term solution was to use algaecide applications at the onset of algal blooms to prevent large algal biomasses from dying off and causing dangerous drops in dissolved oxygen. It was determined that monitoring the pond twice a month would be sufficient to control an algae problem before it got out of hand.
On April 20, 2016, a report and observation of the pond showed a Pithophora heavy algae bloom forming at a rapid pace, going from approximately 2% surface coverage to 20% surface matting in a matter of days. SOLitude responded quickly and after reviewing the weather conditions decided to treat the pond the morning of April 21. Due to the early season nature of the algal bloom, an EPA registered aquatic herbicide was selected as the product of choice for its residual and nutrient-reducing properties. The thought was that removing some of the nutrients from decomposing algae mats would reduce the severity of future blooms as the 2016 growing season progressed. At the time of treatment, the current pond depth brought the acre-feet to just less than 15 feet and an environmentally sensitive aquatic product was applied. It was mixed with a 1.5 HP transfer pump directly with pond water in a boat-mounted spray tank and then spread across the surface with high pressure, breaking up the algal mats in the process. The algaecide mixture was also spiked with herbicide and surfactant to assist in breaking the cell walls of the Pithophora algae. Air temperature at the time of treatment was 67 degrees Fahrenheit and the sky was partly cloudy.
Six days later, on April 27, we returned to the pond to observe the results of the treatment and were amazed at what we found. The pond was completely cleared of algae and looked great! There was no evidence of the algal bloom anywhere in the pond, and SOLitude staff did not even see dead or decomposing algae in the water column. The HOA and SOLitude staff are very happy with the results and plan to continue using the selected aquatic herbicide as part of a permanent program to keep algae biomass and nutrient reintroduction down. Later in the season (June 30), a water sample showed the dissolved oxygen over 11 mg/L, which satisfied the main goal of preventing the algal mass from creating an unstable environment for fish and other wildlife.