Cape Town dam levels: September sees below average rainfall

The City of Cape Town today published its latest dam storage report, but it makes for bleak reading. Although no massive drops have been reported, no substantial increases can be noted either (pdf).

And Cape Town needs a substantial increase.

Note: see last week’s dam levels report here.

The largest dam in the system — the Theewaterskloof — continued its negative trend this week, dropping 0.1% to 28.3% capacity. Following suit was the Steenbras Lower Dam, now just 45.5% full, down from 46.3% a week earlier.

But gains have been made by some of the other stores.

The Franschhoek’s Berg River Dam, for one, continues to hold more water each week and is now 65% full. It’s now just over 8% off October 2016’s capacity.

The Steenbras Upper Dam in Gordon’s Bay is also now over 100% full, holding 5% more water than at the same point last year. And finally, the Voelvlei and Wemmershoek Dams have also recorded increases to their hold, with 0.1% and 0.3% gains respectively.

Above: Cape Town dams’ current capacity in million litres (ML), info sourced from the City of Cape Town

Notably, both of the above dams benefitted from last week’s cold front, which brought 17mm and 18.3mm to the dams’ catchment areas respectively. Both however missed their September long-term rainfall averages by more than 40%.

113.7mm fell in Newlands in September, while the Theewaterskloof experienced just 20.8mm of rainfall last month. It usually experienced slightly less than 40mm.

But rainfall is seemingly an issue across the rest of the province too.

The Western Cape’s total dam storage level stood at 37.3% on 20 September, with some reservoirs dwindling even lower than that.

Price Albert’s Oukloof Dam, the Stompdrift Dam near De Rust and the Kammanassie Dam south of Oudtshoorn are all below 6%. The Garden Route Dam is just over 50% full, while the Brandvlei Dam outside Worcester is just over 33%.

As for Cape Town’s water consumption, the city’s residents continue to use too much water.

“Collective usage is at 618-million litres per day. This is 118-million litres above the necessary consumption target,” the City wrote in a press release.

To add to the pressure, the City also mentioned the “new National Government restriction targets” which requires the City of Cape Town to reduce its usage by 40%.

“To date, the national restriction has been 20%, which the City met successfully,” the City added.

“A reduction of 40% would equate to about 520-million litres of collective usage per day. As can be clearly seen, the City has been ahead of the curve by already having a target in place that is even lower than the new restriction target. This has been in an effort to act conservatively, proactively and to base our modelling on a worst-case scenario,” noted Xanthea Limberg, the City of Cape Town’s Mayco member for water and waste services.

“With the harsh summer ahead, rapid decline of dam levels should be expected. This year it will also be from lower levels.”

Rainfall is forecast for Cape Town on Tuesday and Wednesday.

Feature image: Hely-Hutchinson Reservoir, Table Mountain, by Damien du Toit via Flickr (CC 2.0 BY, resized)