Hartbeespoort Dam before the sluice gates: When the Crocodile River ruled the valley
Before the dam: A river through the mountains
Long before Hartbeespoort Dam became one of South Africa’s best-known inland recreational destinations, the landscape looked very different. Where boats now sail and waterfront homes overlook the water, the Crocodile River once wound through a fertile valley beneath the towering Magaliesberg mountains. The construction of the dam transformed this landscape forever.
Before the construction of Hartbeespoort Dam in the early 1920s, there was no vast expanse of water separating the northern and southern shores of what is now Hartbeespoort.
Instead, the Crocodile River flowed through the valley, fed by tributaries draining parts of the Witwatersrand and surrounding countryside.
The river passed through a dramatic natural opening in the Magaliesberg mountain range, where the dam wall would eventually be built.
The surrounding landscape consisted of riverbanks, farmland, natural vegetation and the slopes of the Magaliesberg. Seasonal rainfall influenced the river’s flow, with summer floods bringing large volumes of water downstream and dry periods reducing its level.
For generations, the valley provided water, grazing and fertile ground for communities living in the area.
The Magaliesberg had been inhabited and used by indigenous communities long before European settlement. In the nineteenth century, farms were established in the valley and surrounding areas.
The valley before it disappeared beneath the water
The first attempts to tame the Crocodile River
The idea of building a dam in the Hartbeespoort valley dates back to the late nineteenth century.
General Hendrik Schoeman, who owned land in the area, recognised the agricultural potential of storing water from the Crocodile River.
An early attempt to construct a dam, named Sophia Dam after his wife, ended in failure when flooding destroyed the structure.
His son, Johan Schoeman, later revived plans for a much larger dam. By 1905, proposals were being developed to use the narrow Magaliesberg gorge to create a major irrigation reservoir.
However, political upheaval, financial difficulties and the First World War delayed construction.
Building the dam that changed Hartbeespoort forever
Work on the dam faced repeated setbacks, particularly because of flooding.
In March 1921, floodwaters damaged the temporary structures intended to keep the river away from the construction site.
Engineer F.W. Scott subsequently redesigned the wall as a concrete arch structure, using the surrounding rock formations to support the enormous pressure of the stored water.
On 24 May 1921, the river was successfully diverted. Concrete was placed in the foundations during July, and by September the wall was already rising above the riverbed.
The main dam wall was completed in April 1923, and the road across it opened in September of that year.
The reservoir continued filling, reaching full capacity in March 1925.
A different Hartbeespoort Dam before the steel sluice gates
What many Hartbeespoort residents may not realise is that the original dam looked significantly different from the structure visible today.
The ten large steel sluice gates familiar to motorists and visitors were not part of the original dam wall.
For more than four decades after its completion, Hartbeespoort Dam operated without these modern crest gates.
Instead, excess water flowed over a fixed concrete spillway on the western side of the wall.
When the reservoir reached its overflow level, water passed over the spillway and descended towards the Crocodile River below.
The original design did include outlet structures and valves to supply the irrigation canals. It is therefore important to distinguish between these original water-release systems and the large steel gates installed much later.
The major change in 1969
By the 1960s, the demand for irrigation water had increased, and engineers sought ways to increase the dam’s storage capacity without rebuilding the entire structure.
The solution was to install ten steel radial crest gates on the existing spillway.
The gates, approximately 2.74 metres high, were installed in 1969, with some historical accounts referring to the completed modification around 1970.
This engineering modification raised the dam’s full supply level by approximately 2.4 metres.
The result was a substantial increase in the amount of water the reservoir could hold.
Did the higher water level change the shoreline?
Yes. Raising the full supply level meant that water could extend farther into low-lying areas around the reservoir when it was full.
This was particularly significant for the gently sloping shores, where a relatively small vertical rise could cause water to cover additional ground.
The extent of the change depended on the shape and elevation of the shoreline.
Some areas that had previously remained above the normal full-water level could now be submerged when the dam reached its new capacity.
This means that the shoreline familiar to residents today is not exactly the same as the shoreline during the dam’s first four decades.
From irrigation reservoir to holiday destination
Although Hartbeespoort Dam is now associated with boating, tourism, restaurants and residential estates, recreation was not the original reason for its construction.
Its principal purpose was to supply irrigation water to agricultural land in the Brits area.
The irrigation canals transformed farming opportunities north of the Magaliesberg and contributed to the development of the surrounding region.
Over time, the permanent body of water attracted holidaymakers, anglers, boating enthusiasts and property developers.
Communities such as Schoemansville, Meerhof and Kosmos became closely associated with the reservoir and its spectacular mountain setting.
The later installation of the steel gates formed another important chapter in this transformation
A century of change
Today, Hartbeespoort Dam is so closely identified with its famous wall and steel sluice gates that it is easy to assume they have always been there.
But the dam has passed through three distinct stages: first, the natural Crocodile River valley before construction; then the original reservoir with its fixed overflow spillway; and finally, the enlarged reservoir with the steel crest gates that are familiar today.
The next time motorists cross the dam wall or watch water pouring through its gates, they are looking at more than an engineering structure.
They are seeing a century of change in the Hartbeespoort landscape — from a river winding through the Magaliesberg to one of South Africa’s most recognisable dams.
And beneath the waters of Hartbeespoort lies the memory of a valley that existed long before the first concrete was poured.
Historical timeline
1. Before 1900 — The Crocodile River flows naturally through the Magaliesberg valley. Early dam-building efforts begin.
2. 1905 — Plans for a larger irrigation dam gain momentum.
3. 1921 — F.W. Scott redesigns the dam wall and major construction advances.
4. 1923 — The main dam wall is completed.
5. 1925 — The reservoir reaches full supply level and overflows.
6. 1969–1970 — Ten steel radial crest gates are installed, increasing storage capacity.
7. Today — The dam remains an important irrigation reservoir and a major recreational landmark.
Historical references: Water Research Commission, South African Institution of Civil Engineering, International Commission on Irrigation and Drainage, and Kormorant’s earlier feature Hartbeespoort – How it Began.
