Updated 17 Oct 2016
Archaeological record shows that the narrow gorge through which the confluence of the Crocodile and Magalies Rivers cuts through Magalesberg mountains has been of economic and social importance to Late Stone Age and Early Iron Age cultures for many hundreds of years. The first attempt to dam the Crocodile River was made by General Hendrik Schoeman in 1898 at what are now the headwaters of the dam. The dam was designed to supply water to the proposed town he called Schoemansdal and to irrigate 2000 ha of land. Unfortunately floods destroyed the stone and cement wall the following year but remnants of the intricate system of aqueducts and canals can still be seen.
After the end of the South African War in 1902 a Swedish engineer August Karlson proposed damming the river at the poort to create a larger reservoir than Schoeman's that would supply the Witwatersrand and its mines with water and hydro-electricity. The matter was shelved at that time, but resurrected between 1905 and 1908 when a full 'Reconnaissance of the Basin of the Western Crocodile River' was conducted by the Transvaal colonial government. This comprehensive report provided designs for an extensive network of dams on all of the rivers flowing north from the Magaliesberg. Engineering drawings of proposed dam walls, full hydrological descriptions, financial estimates and surveys of existing weirs and impoundments were given in detail.
With the creation of the Union of South Africa in 1910 responsibility for the dam shifted to the national government who recognized the economic potential of the dam and also saw it as a partial solution to question of uplifting poor whites at a time of economic depression and unemployment. Only white labour would be used and the irrigation scheme that resulted would also assist poor white people to engage in productive agriculture. According to one source, the "primary purpose of the dam in its original conception was contribute towards a solution of South Africa's ever increasing 'poor white' problem". The Geological tests were carried out in 1913 and the Hartebeestpoort Irrigation Scheme (Crocodile River) Act No. 32 was promulgated in 1914. The scheme suffered a setback with the outbreak of the First World War and the 1914 Rebellion and progress was only resumed in 1916. Two years later floods swept away part of the construction site causing further delay and the design of the wall was revised by A.W. Scott to allow it to be anchored into the cliffs on both sides of the river.
An interesting aspect of the wall is the "Victory Arch" built on pseudo-classical lines to celebrate the struggle against poverty. The inscriptions on either face of the arch read: "Sine aqua arida ac misera agri cultura." (Without water agriculture is withered and wretched) and "Dedi in deserto aquas flumina in invio" (I will pour water on the thirstly land and streams on the dry ground – Isaiah 44.3)
In 1923 the dam was finally completed and the road over the wall was opened to traffic and by 1930 the last of the network of more than 100km of irrigation canals was completed.
As the dam began to fill Hendrik Schoeman's town of Schoemansdal and the resort town of Kosmos were laid out on its banks. Soon the recreational value of the lake began to draw visitors from nearby Pretoria and Johannesburg and the economic boom in the 1990s saw an explosion of tourism and property development in the area.
Hartbeespoort Dam is a complex water body with abnormal nutrient loading from the cities in its catchment area, high solar radiation and low wind speeds creating conditions for eutrification and the prolific growth algae and weed. Research studies have been undertaken regularly since 1978 but water quality continues to deteriorate.
It is today a popular resort for for water sports and golfing on nearby golfing estates for more affluent middle class South Africans.