Work wisely with water
Despite the generous rain the Overstrand received over the weekend, residents and visitors are urged to double up on their water conservation efforts, as below-average rainfall figures have left the De Bos Dam level at just over 44%, with the warm and dry summer season sets in.
According to the Overstrand Municipality, from January to August this year only 337.5 mm rain was recorded, compared to an average of 450 mm in previous years for the same period. In fact, the annual rainfall for the area has been below normal since 2015 when, according to statistics of the South African National Space Agency (SANSA), a total of 466.6 mm was recorded against an annual average recorded over the last 70 years of 606.1 mm. Rainfall of 538.9 mm was recorded in 2016, 524.5 mm in 2017 and 504.2 mm in 2018, according to SANSA.
The monthly rainfall figures measured for the first 8 months of this year are equally concerning. In January 20.5 mm was measured against an average of 25.4 mm. In February the figure was 15.8 mm compared to an average of 29.2 mm. March brought some relief with 94.6 mm compared to 32.7 mm, but April measured 36.9 mm against 55 mm, May 23.5 mm against 58.9, June 55 mm against 79.9 mm, July 64 mm against 84.2 mm, and in August only 27.2 mm was recorded against an average of 81.3 mm.
Johan Montgomery, the viticulturist at Hamilton Russell Vineyards, says not only was much less rain recorded than in previous years, but the rain that did fall did not result in sufficient runoff. “Most of the rainfall that was measured during the year was during showers, with very little or no follow-up rain. Because of the dry ground conditions, there is virtually no runoff into streams and dams that supply the De Bos Dam,” said Montgomery.
He added that rainfall of more than 12 mm at a time, with generous follow-up rain, is what is needed to break the dry cycle. “We do regular ground moisture checks and we have never seen the ground as dry as it is now. This means that in addition to the low rainfall, there is little to no runoff, resulting in drier farm dams. The rain over the weekend (between 12 mm and 18 mm) was a blessing as it resulted in much-needed ground moisture for the vines in the valley that are just now reaching the budding phase. The buds for this year are looking good, better than last year, and we are hopeful that over the next few months there will be enough rain for us to deliver a good harvest,” he said.
At the beginning of November 2017, the municipality implemented level 1 water restrictions for the Greater Hermanus area and upgraded it to level 2 in June 2018. According to the municipality, until such time as the De Bos Dam has reached a level of at least 70%, water restrictions and the concomitant restrictive tariffs will remain in force, and the implementation of stricter restrictions may have to be considered in the short term.
“Apart from more stringent water usage restrictions, level 2 restrictions include the first level of water-restriction tariffs for Greater Hermanus. Although the tariff for domestic water use up to 6 kl per month has not increased, the tariffs for domestic use above 6 kl per month increased by 30% in terms of the water-restriction tariffs. The water tariff for all non-domestic use has also increased by 30%. This translates to an extra R3.96 more per kilolitre above the 6 kl-mark. Users who use more than 60 kl per month are paying an extra R21.32 per kilolitre above 60 kl, which means a total cost of R78.40 per kilolitre above 60 kl usage in one month,” the municipality said in a press release.
“Water restrictions are in a place of necessity as a temporary measure to discourage excessive water use and to preserve the water level of the dam. This leads to lower consumption, and the accompanying water restriction tariffs do not, therefore, generate additional income,” according to the municipality.
Hermanus residents co-operated very well in saving water over the last 10 years, despite a rapidly growing population during this period. The town’s total annual potable water demand for 2018/19 was 6.8% (258 000 kl) less than in 2005/06 and 10.1% (409 000 kl) less than in 2015/16.
Generous rainfall of 77.7 mm in September 2018 gave the De Bos Dam a boost to stand at 67.95% at the beginning of October, compared to this year’s 44.2%. In comparison, only about 25 mm of rain has been recorded during the first four weeks of September. The average daily consumption of water over the past few months has been in the region of 10 million litres per day. In summer this number increases to more than 13 million litres per day, peaking during Christmas and New Year at over 15 million litres.
According to the municipality, the 10 boreholes that are also supplying water to Hermanus are being used optimally and contributed 2 456 million litres to the Hermanus bulk water supply since October 2016; more than 30% of total demand over the period, thereby contributing significantly to the preservation of the De Bos Dam level.
“Two new boreholes have been drilled successfully during the past two months in the Gateway well field. These boreholes are currently being tested, after which equipment specifications and designs can be finalised and tenders called for their completion and commissioning as production boreholes. It is envisaged that the boreholes will come into production during the second quarter of 2020.
“In addition, feasibility studies are in an advanced stage for the implementation of seawater desalination in the Hermanus area in the medium term,” said the municipality.
LEVEL 2 RESTRICTIONS
- If you use municipal water to water your garden, you may only do so for one hour per week, before 09:00 or after 17:00, on one day per week only. The day of the week is determined in accordance with street numbers. For residents with even numbers, it is Wednesdays only, and for those with uneven numbers, Tuesdays only.
- The use of irrigation systems is still allowed but only for one hour per week.
- Vehicles and boats may only be washed with a bucket and cloth and the hosing down of hard surfaces or paved areas is prohibited.