February ice and deep snow does not mean you can ignore the pond.

Properly constructed ponds seldom are frozen deep enough to harm fish. This is because as long as light can penetrate the ice layer, aquatic plants continue to produce oxygen — especially microscopic plants commonly found in ponds.

However, snow blanketing the ice for more than three consecutive weeks prevents light penetration and aquatic plants can no longer photosynthesize and produce oxygen.

If snow cover is prolonged more than three weeks, aquatic plants start to die and become organic matter. To compound the issue, bacteria in the pond will decompose the dead vegetation (organic matter). During this process, the bacteria will respirate by taking in available dissolved oxygen from the water and release carbon dioxide. Between the aquatic plants dying and the bacteria breaking down the organic matter the dissolved oxygen in the water decreases. If the dissolved oxygen falls below 6 ppm, fish become stressed. As dissolved oxygen continues to decrease beyond that point, fish suffocation and death may occur.

Winter’s severity is one of the foremost factors increasing the likelihood of a winter fish kill. Pond owners should be most concerned during a harsh winter in which ice cover persists and there is considerable snow cover on the ice. Ponds that contained a lot of aquatic plants the previous summer, and ponds that have large fish concentrations are more prone for winter fish kills.

Fortunately, winter fish kills can be prevented in most cases by removal of snow from at least twenty-five percent of the pond surface. Before any type of snow removal can occur on ponds, several precautionary measures need to be examined. Ice is generally thinner where there is moving water, such as inlets and outlets, decks and docks, and objects that protrude through the ice. Another consideration is the use of pond aerators during the winter. Though they produce oxygen to help prevent fish kills, they also produce uneven and dangerous ice conditions.

If ice at the shoreline, is cracked or squishy, stay off. Do not go on the ice during thaws. Avoid honeycombed ice, dark snow and dark ice. Never assume the ice is thick enough to support your weight. Check it. Start at the shoreline and using a cordless drill with an inch paddle bit, make test holes and measure at intervals as you proceed onto the ice.

As a rule of thumb, (for new, clear ice) there should be a minimum of 4-6 inches of ice to support a few, well- dispersed people, 6 to 7 inches for small, on-foot group activities, and at least 8 to 10 inches for snowmobile activities. This information on ice thickness is based on recommendations from the Cold Regions Research Laboratory in Hanover, New Hampshire.

What is your liability if someone is harmed in your pond? Should you take precautions to prevent access to a pond? Ohio law establishes legal duties a landowner has to visitors in and around the pond and provides protection from liability in certain situations, such as an inherent dangerous condition. An inherent dangerous condition is one that creates an unreasonable and unnecessary risk of harm that is not readily apparent to the visitor.

Is a pond a “dangerous condition” for which a landowner could be liable? Ohio courts have determined that a pond is not an inherently dangerous condition. Rather, a pond is an “open and obvious danger,” and the landowner and any visitors are expected to realize the risk of drowning or being harmed in a pond. However, if pond is frozen over and covered with snow, pond is not readily seen as it is in unfrozen conditions.

What should you do about trespassers? What if a child or an adult trespass and drowns in a pond?

The “attractive nuisance doctrine” adopted by the Ohio Supreme Court and later enacted by the Ohio Legislature places a duty upon landowners to protect a foreseeable child trespasser from “dangerous artificial conditions” on the property that attract a child who cannot recognize the danger. A landowner can be liable for the child’s harm and for harm to an adult attempting to rescue the child if the landowner did not take steps to protect the child from the danger, even if the child and rescuer were trespassing. Does a pond qualify as a “dangerous artificial condition” for purposes of the attractive nuisance doctrine? Ohio courts have not had a case on this issue, but at least one court has suggested evidence that a pond is artificially created could result in the landowner being subject to the attractive nuisance doctrine. An example how this could be challenged is a snowmobile trespasses and drives over frozen snow-covered pond with weak ice and falls through.

Based upon Ohio law, the following steps can help reduce the possibility of liability if someone suffers injury in or around your pond:

Limit or deny access to the pond by fencing or other means, especially if children might be trespassing around the pond. Some townships and municipalities may require fencing around ponds. Check with the local zoning authority on local requirements.

Post signs around the pond that warn of deep water, steep banks, sudden drop-offs or underwater obstacles like stumps, pumps, and fish attractors. Identify no access areas and indicate the depth of the pond. Be aware that children may not be able to read or comprehend a sign. Use both written and visual signs that span multiple reading comprehension levels.

Install a pond rescue post that contains lifesaving equipment and other aids that could help rescue a visitor or trespasser, such as ladders, benches, or a nylon rope with a life buoy, long enough to reach the middle of the pond.

Be on the safe side and plan for more than is expected. For more information on Pond Liability issues in Ohio, refer to- Ohio State University Extension Farm Office Premises Liability Law Library Ponds and Legal Liability. https://farmoffice.osu.edu/our-library/premises-liability-law

For more information on causes and prevention of Winter Fish Kills in ponds refer to 2018 Ohio State University Extension Pond Update. https://senr.osu.edu/sites/senr/files/imce/images/Winter2018_0.pdf