Sinkholes vary in shape and size. In regions of karst, sinkholes are formed by the removal of material such as limestone bedrock, from below by underground water flow. Some Sinkholes have the appearance of ponds - but don't be confused. The pond is simply a sinkhole that has trapped storm water run-off which is slowly infiltrating into and through the sediments overlying the limestone bedrock. Some sinkholes may flood only during periods of high rainfall and others are dry.
Sinkholes are direct connection to our groundwater through cracked and crevice limestone.
The run-off that enters through sinkholes are not filtered as it joins the groundwater system.