Orange Township's ponds are getting old.
A sign at the pond at Township Hall Park, 1680 E. Orange Road, warns of algal blooms and the presence of toxins, urging people not to come into contact with the water.
That pond is one of three, along with two others at North Orange Park, for which the township is responsible. Other stormwater-retention ponds in the township were constructed by developers and do not fall under the direct supervision of the township, officials said.
Trustee Lisa Knapp said the quality and visual appeal of the township's three bodies of water is an ongoing issue that trustees are taking steps to rectify.
"We've been getting complaints about the ponds, mostly just how bad they look," Knapp said. "We're starting to learn of the potential health risk as well."
According to the Environmental Protection Agency, algal blooms can produce toxins that can sicken or kill people and animals, as well as create dead zones in water.
Township officials heard from Eugene Braig, program director, aquatic ecosystems for Ohio State University Extension, at the Aug. 19 board of trustees meeting.
Braig told officials that surface growth can be part of the natural aging process of ponds, and that the aging process can be accelerated in urban ponds, which often lack depth and volume and are built specifically to collect not just stormwater but also sediment, which further reduces depth and volume.
Braig said he did not find evidence of algal bloom or toxins at the North Orange Park ponds. However, the pond at Township Hall Park, which existed on private property prior to its acquisition by the township, is much older and shows "evident microcystic bloom, which, in heavy concentrations, has the potential to produce toxins."
"The township did the right thing by posting the signage," Braig said.
Solutions, Braig said, "depend on what the township wants to do with those sites, and the intent of having the ponds."
A fundamental approach, he said, would be to dredge the ponds, assuring they are at recommended depth and volume for stormwater or for stocking fish, again depending on the intent of the township. Braig also said the pond at Township Hall Park could be converted into a managed wetland.
"An open-water pond has a certain aesthetic, but a wetland can serve an important function and also be a beautiful space," Braig said.
Knapp said officials are weighing immediate options for all three ponds and prioritizing a long-term management plan.
Finances, she said, will play a role in the decision. She estimated dredging all three ponds could cost between $50,000 and $100,000 each.