Known locally as the dam artificial body of water which was created by the 6th Earl of Mar in 1713 to provide water power for pumping the coal mines in the vicinity. Up to 17 water wheels were used to move and pump the water
A weir was built on the Black Devon river at Forestmill and a lade aqueduct dug out 2 miles to the marshy hollow that was then Gartmorn.
An earthen dam held back the water providing a constant supply for Sauchie Pumps. Once this Dam was full it was flushed through a pipe system and with the flow of water silt which had built up in Alloa Harbour was removed making it easy for Ships to Dock in Alloa. Thus the water went full cycle and was completely regenerated.
The tail race down to the forth from the Gartmorn Dam together with the flow from local burns provided power for Alloa industries such as Tobacco snuff and corn grinding which were later replaced by distilling brewing and spinning. Before steam power took over in the 1860’s the tail race powered up to three colliery engines and 9 mills
In the early 19th Century Alloa grew in population and more demand was needed for water. In 1820 the Earl of Mar granted the Burgh the right to extract water from the tail race in 1891 the Alloa water act was passed and the reservoir was in enlarged and filter station was built the dam was then able to supply to the growing pop and local industry and did so for the next 100 years