Theewaterskloof Dam: Difference between revisions
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'''Theewaterskloof Dam''' is an earth-fill type dam located on the [[Sonderend River]] near [[Villiersdorp]], [[Western Cape]], [[South Africa]]. Administratively it is located within [[Theewaterskloof Local Municipality]]. It was established in 1978 and forms a major component of the [[Western Cape Water Supply System]].<ref>[http://www.dwaf.gov.za/iwqs/gis_apps/dam/dams/index.htm List of South African Dams] from the [[Department of Water Affairs]]</ref> The dam mainly serves for municipal and industrial use as well as for irrigation purposes. The hazard potential of the dam has been ranked high (3). |
'''Theewaterskloof Dam''' is an earth-fill type dam located on the [[Sonderend River]] near [[Villiersdorp]], [[Western Cape]], [[South Africa]]. Administratively it is located within [[Theewaterskloof Local Municipality]]. It was established in 1978 and forms a major component of the [[Western Cape Water Supply System]].<ref>[http://www.dwaf.gov.za/iwqs/gis_apps/dam/dams/index.htm List of South African Dams] from the [[Department of Water Affairs]]</ref> The dam mainly serves for municipal and industrial use as well as for irrigation purposes. The hazard potential of the dam has been ranked high (3). |
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It is the largest of the [[Cape town supply dams|6 major dams]] in the |
It is the largest of the [[Cape town supply dams|6 major dams]] in the [[Western Cape]] with a capacity of 480 188 million litres. 8 minor dams also contribute to dam levels supplying water to the province. The dam stores about 41% of the water stored for cape town city council. |
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A dry period of rain in 2017 saw the levels drop to 12.9%. |
A dry period of rain in 2017 saw the levels drop to 12.9%. |
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3 water extraction towers are in operation, one for drinking water and the other two for municipal and irrigation. |
3 water extraction towers are in operation, one for drinking water and the other two for municipal and irrigation uses. |
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[[File:Theewaterskloof Dam water extraction point.jpg|thumb]] |
[[File:Theewaterskloof Dam water extraction point.jpg|thumb]] |
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== Water restrictions == |
== Water restrictions == |
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A heavy rain event in June 2017 saw an increase in the catchment areas and level increased to over 15%. The last 10% is mostly unusable. Water restrictions by provincial government to meet a target of 600 million litres of water per day were introduced in 2016.<ref>{{Cite web|url=https://www.capetown.gov.za/Family%20and%20home/Residential-utility-services/Residential-water-and-sanitation-services/2016-residential-water-restrictions-explained|title=Residential water restrictions explained|last=|first=|date=|website=www.capetown.gov.za|language=en|archive-url=|archive-date=|dead-url=|access-date=2017-06-13}}</ref> Currently, residents are restricted to 100 litres of water per day with car washing, pool level filling and lawn watering not allowed. |
A heavy rain event in June 2017 saw an increase in the catchment areas{{Dubious|reason=Rainfalls don't increase catchment areas|date=October 2017}} and the level increased to over 15%. The last 10% is mostly unusable. Water restrictions by provincial government to meet a target of 600 million litres of water per day were introduced in 2016.<ref>{{Cite web|url=https://www.capetown.gov.za/Family%20and%20home/Residential-utility-services/Residential-water-and-sanitation-services/2016-residential-water-restrictions-explained|title=Residential water restrictions explained|last=|first=|date=|website=www.capetown.gov.za|language=en|archive-url=|archive-date=|dead-url=|access-date=2017-06-13}}</ref> Currently, residents are restricted to 100 litres of water per day with car washing, pool level filling and lawn watering not allowed. |
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The City of Cape Town Council increased the water restriction level from 4 to 4b, on 1 July 2017, encouraging water users to utilise no more than 87 litres of water per person per day. |
The City of Cape Town Council increased the water restriction level from 4 to 4b, on 1 July 2017, encouraging water users to utilise no more than 87 litres of water per person per day. |
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Media footage of the declining dam level sparked the importance of conserving water. Provincial government is considering tapping into a sensitive aquifer and investing in a desalination plant to |
Media footage of the declining dam level sparked the importance of conserving water. Provincial government is considering tapping into a sensitive aquifer and investing in a desalination plant to augment the water supply.<ref>{{Cite web|url=https://www.enca.com/south-africa/western-cape-dam-levels-up-only-15-percent-after-storms|title=Western Cape dam levels up only 1.5% after storms|website=www.enca.com|language=en|access-date=2017-06-13}}</ref> It is expected that at least 3 years (past 2020) of winters are necessary for this dam to return to previous healthy levels. |
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== Rainfall and capacity == |
== Rainfall and capacity == |
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Theewaterskloof dam has a capacity of 480 406 000 cubic metres of water. The catchment area of 500 square kilometers is served by streams emanating in the Hottentots Holland |
Theewaterskloof dam has a capacity of 480 406 000 cubic metres of water. The catchment area of 500 square kilometers is served by streams emanating in the Hottentots Holland mountain range. This area has a long-term average of 69 days with precipitation per year<ref>{{Cite news|url=https://www.yr.no/place/South_Africa/Western_Cape/Theewaterskloofdam/statistics.html|title=Weather statistics for Theewaterskloofdam|last=institutt|first=NRK og Meteorologisk|work=yr.no|access-date=2017-07-10|language=en-gb}}</ref>. Historically<ref>{{Cite web|url=https://www.dwaf.gov.za/Hydrology/Verified/HyData.aspx?Station=H6E00110.00&DataType=Monthly&StartDT=1974-11-30&EndDT=2017-02-01&SiteType=MET&Format=Old|title=Rainfall History|last=|first=|date=|website=|archive-url=|archive-date=|dead-url=|access-date=}}</ref> records show we are in a dry period <ref>{{Cite web|url=https://www.dwaf.gov.za/Hydrology/Provincial%20Rain/Default.aspx|title=Western Cape rainfall|last=|first=|date=|website=|archive-url=|archive-date=|dead-url=|access-date=}}</ref> 1mm of rain per square meter equates to 500 000 000 litres falling on this area. It takes a few days for all the runoff to reach the dam. Evaporation and how saturated the ground is affects the amount of water reaching the dam. An average amount of between 9% and 15% is used to offset the values against evaporation and soil absorption. A deeper dam has less evaporation due to less surface area. |
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Revision as of 02:08, 26 October 2017
| Theewaterskloof Dam | |
|---|---|
 View of Theewaterskloof reservoir between Grabouw and Villiersdorp | |
| Location | Western Cape, South Africa |
| Coordinates | 34°4′41″S 19°17′21″E / 34.07806°S 19.28917°E |
| Purpose | Irrigation and domestic |
| Opening date | 1980 |
| Owner(s) | Department of Water Affairs |
| Dam and spillways | |
| Type of dam | Earth fill dam |
| Impounds | Sonderend River |
| Height | 25 m |
| Length | 646 m |
| Reservoir | |
| Creates | Theewaterskloof Dam Reservoir |
| Total capacity | 480 406 000 m3 |
| Catchment area | 500 km2 |
| Surface area | 5 059 ha |
Theewaterskloof Dam is an earth-fill type dam located on the Sonderend River near Villiersdorp, Western Cape, South Africa. Administratively it is located within Theewaterskloof Local Municipality. It was established in 1978 and forms a major component of the Western Cape Water Supply System.[1] The dam mainly serves for municipal and industrial use as well as for irrigation purposes. The hazard potential of the dam has been ranked high (3).
It is the largest of the 6 major dams in the Western Cape with a capacity of 480 188 million litres. 8 minor dams also contribute to dam levels supplying water to the province. The dam stores about 41% of the water stored for cape town city council.
A dry period of rain in 2017 saw the levels drop to 12.9%.
3 water extraction towers are in operation, one for drinking water and the other two for municipal and irrigation uses.
Water restrictions
A heavy rain event in June 2017 saw an increase in the catchment areas[dubious – discuss] and the level increased to over 15%. The last 10% is mostly unusable. Water restrictions by provincial government to meet a target of 600 million litres of water per day were introduced in 2016.[2] Currently, residents are restricted to 100 litres of water per day with car washing, pool level filling and lawn watering not allowed.
The City of Cape Town Council increased the water restriction level from 4 to 4b, on 1 July 2017, encouraging water users to utilise no more than 87 litres of water per person per day.
Media footage of the declining dam level sparked the importance of conserving water. Provincial government is considering tapping into a sensitive aquifer and investing in a desalination plant to augment the water supply.[3] It is expected that at least 3 years (past 2020) of winters are necessary for this dam to return to previous healthy levels.
Rainfall and capacity
Theewaterskloof dam has a capacity of 480 406 000 cubic metres of water. The catchment area of 500 square kilometers is served by streams emanating in the Hottentots Holland mountain range. This area has a long-term average of 69 days with precipitation per year[4]. Historically[5] records show we are in a dry period [6] 1mm of rain per square meter equates to 500 000 000 litres falling on this area. It takes a few days for all the runoff to reach the dam. Evaporation and how saturated the ground is affects the amount of water reaching the dam. An average amount of between 9% and 15% is used to offset the values against evaporation and soil absorption. A deeper dam has less evaporation due to less surface area.
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Social events
The Theewaterskloof Dam is also the home of the annual Synergy Live music festival, one of the biggest outdoor music festivals in South Africa, which typically takes place on the last weekend of November or the first weekend of December.[7]
See also
References
- ^ List of South African Dams from the Department of Water Affairs
- ^ "Residential water restrictions explained". www.capetown.gov.za. Retrieved 2017-06-13.
{{cite web}}: Cite has empty unknown parameter:|dead-url=(help) - ^ "Western Cape dam levels up only 1.5% after storms". www.enca.com. Retrieved 2017-06-13.
- ^ institutt, NRK og Meteorologisk. "Weather statistics for Theewaterskloofdam". yr.no. Retrieved 2017-07-10.
- ^ "Rainfall History".
{{cite web}}: Cite has empty unknown parameter:|dead-url=(help) - ^ "Western Cape rainfall".
{{cite web}}: Cite has empty unknown parameter:|dead-url=(help) - ^ "Synergy". Synergy. 2015. Retrieved 30 May 2017.
External links
