DNREC Treats Griffith Lake for Aquatic Weeds


Staff Report

On Thursday, May 17 Delaware’s Department of Natural Resources and Environmental Control (DNREC) announced that as inland water temperatures rise and aquatic plants emerge, DNREC’s Division of Fish & Wildlife has started treating several downstate ponds for nuisance aquatic weeds. These nuisance weeds, if left unchecked, can choke the water they have invaded, crowd out beneficial plant species and prevent fishing and boating access. Griffith Lake, near Milford, was treated on May 8. Other public-access ponds to be treated are Horsey Pond and Chipmans Pond near Laurel and Millsboro Pond.

Hydrilla, a non-native plant that likely entered the state through the aquarium trade, is the primary target of the treatment. The Division of Fish & Wildlife’s Fisheries Section is applying Sonar, an EPA-registered and approved aquatic herbicide containing fluridone, to the ponds. In compliance with new guidelines issued by the EPA, DNREC has filed a notice of intent to use Sonar and has submitted a pesticide discharge management plan to the EPA. Sonar has been used in Delaware since the 1980s and has proven safe and effective for controlling hydrilla. Sonar does not pose any threat to wildlife, including fish.

“There are no restrictions on fishing or consumption of fish as a result of these planned treatments,” said Fisheries Administrator John Clark. Signs will be posted in the boat ramp area of each pond on the day of treatment. The only special precaution for residents is a 30-day restriction from the date of treatment on water use from the ponds.

“Residents who live alongside the ponds and those directly downstream should not use pond water to irrigate their gardens, yards, or agricultural lands for 30 days following treatment to avoid possible damage to their plantings,” Clark said. “To prevent the spread of invasive aquatic vegetation to other ponds and waterways, anglers and boaters are encouraged to remove all hydrilla and other aquatic plants from their boats, trailers and gear before leaving the boat ramp area.”

In the case of state-managed ponds used for crop irrigation such as Griffith Lake, farmers who irrigate from them are contacted prior to treatment to ensure that the 30-day after-treatment water-use restriction will not negatively impact their agricultural activities. In some cases, ponds cannot be treated due to agricultural water needs.

The Division of Fish & Wildlife treats only state-managed ponds that allow public access for anglers, since the treatment work is funded through the Federal Sport Fish Restoration Program and state fishing license funds. While the Division of Fish & Wildlife does not treat private ponds, it can provide upon request a list of businesses licensed in Delaware to treat nuisance aquatic weeds in ponds. For more information on treatment of state-managed ponds, individuals can call the Fisheries Section at 302-739-9914.

Fisheries Administrator Clark also noted the Division of Fish & Wildlife reminds residents that in order to use water from Delaware’s freshwater ponds, an annual permit from DNREC’s Division of Water is required. Residents who have these permits will receive individual notice of the upcoming pond treatments.For information on obtaining an irrigation permit from the Division of Water, individuals can call Bill Cocke, Water Allocation Section, at 302-739-9945.