The first steps taken to develop the Sundays River were made by James Somers Kirkwood who established the Sundays River Land and Irrigation Company in 1883. He dreamed of having a continuous water supply for the valley, but, as at that stage ostrich farming was at a high and the returns on investments were guaranteed and thus a better investment in Oudshoorn, instead of the valley. As the origins of the Sundays River is in the Karroo, which is a dry region and prone to thunderstorms, the need arose to establish a dam to conserve the floodwater. An Act of Parliament established the Sundays River Irrigation Board in 1917 with the sole purpose of constructing Darlington Dam (Lake Mentz). Water is withdrawn from the Gariep Dam at Oviston through the Teebus tunnel, which discharges, into the Teebus River, which flows into the Great Fish River. At the Elandsdrift Dam, approximately 15 kms downstream of Cradock, the water is diverted into a canal, which flows through the Cookhouse tunnel and discharges into the Little Fish River near Somerset East.
The water flows approximately four kilometres to the De Mistkraal Weir, where the water is lifted approximately four metres into a canal, which discharges into the Skoenmakers River, which flows into Darlington Dam. Due to the distance involved from the Gariep Dam to Darlington Dam the Department developed a computer model, which also takes into consideration the quality of the water that is required in Darlington Dam and arranges the releases from Oviston accordingly.
In terms of the National Water Act no 36 of 1998 the Irrigation Board had to transform to a Water User Association with its own Constitution. This was promulgated in the Government Gazette on the 20 August 2004 and the Management Committee was elected during February 2005 and started operating from 1 April 2005.