The location was selected because it was just above the upstream tidal flow of seawater at Colleges Crossing. The concrete structure was completed in April 1892.[3] The dam wall rises 4.57 metres (15.0 ft) and is 81.4 metres (267 ft) in length.[3] The weir has a capacity of 3,430 megalitres (750×10^6 imp gal; 910×10^6 US gal), making it one of the largest weirs in the region.[1] Above the weir is a one-lane road which is open to the public.
The nearby Mount Crosby Pumping Station is used to transport drinking water that is sourced from both the weir and the nearby Lake Manchester Dam, which was built shortly after the Mount Crosby Weir.
Without an ongoing eradication program, water hyacinth weed can choke the waters behind the weir, all the way upstream to Fernvale. In 2009, the weir was flushed to remove algae and organic matter that had built up.[4]
^ abHorton, Helen (1988). Brisbane's Back Door: The story of the D'Aguilar Range. Bowen Hills, Queensland: Boolarong Publications. p. 79. ISBN0-86439-036-X.