Lower Mooney Dam is located on the Mooney Mooney Creek, about 21 km upstream from the Hawkesbury River. In March 1938 the Gosford Mayor turned the tap to add the water from this dam into the small town water supply of the time. It is a concrete arch dam, with a capacity of 1,000 megalitres, and was superseded by the more than 4 times larger 'Upper Mooney Dam' in 1982. There is a set of timber steps and a faint track that leads down to the waters edge on the uphill side of the dam wall, the dam wall is fenced and is clearly out of bounds. A sign reminds visitors that swimming is not allowed.