Welbedacht Dam
Encyclopedia
Welbedacht Dam is situated in South Africa
, and was established in 1973.
Bloemfontein
is the sixth largest city in South Africa
with a population of approximately 300 000. It is situated in the Modder River
catchment which has insufficient water resources to meet the growing water requirements. The water supply to Bloemfontein is therefore augmented from the adjacent Caledon River
by means of the Caledon - Modder River Government Water Scheme (CMRGWS).
It was originally envisaged that Bloemfontein would receive Orange River
Water from Vanderkloof Dam
and the outlet works for the transfer scheme still exist at the dam wall. For various reasons, however, it was decided to construct a smaller scheme on the Caledon River
which could be implemented before completion of the Vanderkloof Dam. The Welbedacht Dam on the Caledon River
was constructed as the main storage element of the CMRGWS and water is abstracted from this dam for transfer to Bloemfontein and various smaller users along the way.
The Welbedacht Dam is a concrete barrage-type dam on the Caledon River
which was designed and constructed by the Department of Water Affairs. The dam has a catchment area of some 15 245 km² with a natural MAR of approximately 1210 million m³/a (1920 to 1987) and was completed in 1973. Its purpose was to supply water to the city of Bloemfontein via the 115 km long Caledon-Bloemfontein pipeline which has a capacity of ~1.157 m³/s. Due to the high sediment concentration in the water, the transfer from Welbedacht Dam is first purified at the Welbedacht Purification Plant which is located just downstream of the Dam. The purification plant has a capacity of 1.68 m³/s
Due to siltation, the storage capacity of the Welbedacht Dam reduced rapidly from the original 115 million m³ to approximately 16 million m³ during the twenty years since completion. This reduction in storage created problems in meeting the Bloemfontein demand at an acceptable level of reliability and as a result, the 50 m high Knellpoort Dam
was completed in 1988. It was the first arch gravity Roller Compacted Concrete (RCC) dam in the world and comprises almost 64 600 m³ rollcrete and 14 200 m³ concrete with a gross storage capacity of 137 million m³.
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
, and was established in 1973.
Bloemfontein
Bloemfontein
Bloemfontein is the capital city of the Free State Province of South Africa; and, as the judicial capital of the nation, one of South Africa's three national capitals – the other two being Cape Town, the legislative capital, and Pretoria, the administrative capital.Bloemfontein is popularly and...
is the sixth largest city in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
with a population of approximately 300 000. It is situated in the Modder River
Modder River
The Modder River is a river in South Africa that forms part of the border between the Northern Cape and the Free State provinces.Modder River may also refer to:* Modder River, Northern Cape - A small town in the Northern Cape....
catchment which has insufficient water resources to meet the growing water requirements. The water supply to Bloemfontein is therefore augmented from the adjacent Caledon River
Caledon River
The Caledon River is located in south-east Africa, rising in the Drakensberg Mountains in Lesotho. Origin in the former bantustan of QwaQwa, near the border with Lesotho, southwest of Witsieshoek. It then flows south-west, marking the border with South Africa and Lesotho before entering South...
by means of the Caledon - Modder River Government Water Scheme (CMRGWS).
It was originally envisaged that Bloemfontein would receive Orange River
Orange River
The Orange River , Gariep River, Groote River or Senqu River is the longest river in South Africa. It rises in the Drakensberg mountains in Lesotho, flowing westwards through South Africa to the Atlantic Ocean...
Water from Vanderkloof Dam
Vanderkloof Dam
The Vanderkloof Dam is situated approximately 130km down stream from Gariep Dam and is fed by the Orange River, South Africa's largest river. Vanderkloof Dam is the second largest dam in South Africa, boasting the highest dam wall in the country at 108m...
and the outlet works for the transfer scheme still exist at the dam wall. For various reasons, however, it was decided to construct a smaller scheme on the Caledon River
Caledon River
The Caledon River is located in south-east Africa, rising in the Drakensberg Mountains in Lesotho. Origin in the former bantustan of QwaQwa, near the border with Lesotho, southwest of Witsieshoek. It then flows south-west, marking the border with South Africa and Lesotho before entering South...
which could be implemented before completion of the Vanderkloof Dam. The Welbedacht Dam on the Caledon River
Caledon River
The Caledon River is located in south-east Africa, rising in the Drakensberg Mountains in Lesotho. Origin in the former bantustan of QwaQwa, near the border with Lesotho, southwest of Witsieshoek. It then flows south-west, marking the border with South Africa and Lesotho before entering South...
was constructed as the main storage element of the CMRGWS and water is abstracted from this dam for transfer to Bloemfontein and various smaller users along the way.
The Welbedacht Dam is a concrete barrage-type dam on the Caledon River
Caledon River
The Caledon River is located in south-east Africa, rising in the Drakensberg Mountains in Lesotho. Origin in the former bantustan of QwaQwa, near the border with Lesotho, southwest of Witsieshoek. It then flows south-west, marking the border with South Africa and Lesotho before entering South...
which was designed and constructed by the Department of Water Affairs. The dam has a catchment area of some 15 245 km² with a natural MAR of approximately 1210 million m³/a (1920 to 1987) and was completed in 1973. Its purpose was to supply water to the city of Bloemfontein via the 115 km long Caledon-Bloemfontein pipeline which has a capacity of ~1.157 m³/s. Due to the high sediment concentration in the water, the transfer from Welbedacht Dam is first purified at the Welbedacht Purification Plant which is located just downstream of the Dam. The purification plant has a capacity of 1.68 m³/s
Due to siltation, the storage capacity of the Welbedacht Dam reduced rapidly from the original 115 million m³ to approximately 16 million m³ during the twenty years since completion. This reduction in storage created problems in meeting the Bloemfontein demand at an acceptable level of reliability and as a result, the 50 m high Knellpoort Dam
Knellpoort Dam
Knellpoort Dam is a dam on the Riet Spruit, near Wepener, Free State, South Africa. It was established in 1988.Due to siltation, the storage capacity of the Welbedacht Dam reduced rapidly from the original 115 million m3 to approximately 16 million m3 during the twenty years since completion...
was completed in 1988. It was the first arch gravity Roller Compacted Concrete (RCC) dam in the world and comprises almost 64 600 m³ rollcrete and 14 200 m³ concrete with a gross storage capacity of 137 million m³.