 Aplin's Weir lies downstream of Gleeson's Weir and is the last weir before the mouth of the river.Aplin's Weir started out as small stop weir, built in 1927 to prevent incursion of salt water into the water supplies pumped from the upstream "Top River" wells, located at the end of Thompson Street, Mundingburra.The original stop weir consisted of a curtain of sheet steel which was driven into the sand to the clay bed.