Complex sentence: In dry conditions the river disappears underground into the sink hole known as Manchester Hole, if Scar House reservoir overflows then water flows past Manchester Hole to Goyden pot another sinkhole.
Split into simpler sentences: In dry conditions the river disappears underground into the sink hole known as Manchester Hole. If Scar House reservoir overflows, water flows past Manchester Hole to Goyden Pot, another sinkhole.