Cape Dams Levels – weekly report (011)

 ShowMe Winelands

Cape Dams Levels – weekly report nr. 011

as at 4th March 2019

                [Hely Hutchinson Dam, Table Mountain – Photo EWISA (Wilma Grebe). Currently 35% full]

The main SW Cape dams saw reduced net outflows week-on-week to 11.2 M.cuM, 1.3% of capacity, while combined water in the 6 dams fell from 493.7 M.cuM to 480.3 M.cuM; i.e. down from 54.0% to 52.7% of overall capacity.

Lest we forget,

during this same week in 2018, generous life-saving transfers from Groenland Water Users’  dams to Steenbras dam peaked at 10 M.cuM. Of this, 4.0 M.cuM had already reached Steenbras Upper Dam with the balance due to follow across the next 14-20 days.

Also, releases of water by DWS to the irrigation schemes stopped by end-February and serious hardship for the agricultural community commenced.

Accordingly, during the same week last year net outflows reduced sharply and the total volume stored fell by a far, far smaller 3.1 M.cuM (0.3%).

Here are the levels of the 6 main dams this week.

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There is a balance of forces pushing and pulling on our water consumption pattern at the moment.

1) summer visitors are leaving, reducing water consumption.

2) evaporation rate is starting to fall, reducing water losses.

3) agricultural irrigation is still operating at full tilt, maintaining outflows.

4) local residents are probably drifting usage upwards toward the allowed daily limit of 105 L/person.

To date, there has been no change in the published restrictions on water use.

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In the following graph we see the weekly net change in total water stored in the six main dams.

Since start of summer, the weekly net outflows from the main dams in 2019 initially closely tracked net outflows that occurred during the same weeks in 2017-18 (green). However, as expected across February, due to high releases of irrigation water this season, the net outflow line (red) diverged and started instead to track more closely to the 2016-17 (black) line.

This pattern is likely to continue until early April at which stage, due mainly to less irrigation releases by that stage, the three lines should once more converge.

                                                          [click on the graph to see an enlarged version]

Read here about the revised Cape Town water restrictions operative since 1st December 2018.

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The weather over the SW Cape for March is predicted to be mild and balmy with occasional rain and stronger falls of 15+ mm around 25th.

Two recent ‘MUST READ’ documents published by City of Cape Town :

1) the WATER OUTLOOK 2018 REPORT published 31st December 2018 by City of Cape Town, Water and Sanitation Department. It may be found here http://www.bit.ly/CCTrepDec18.

2) the CAPE TOWN DRAFT WATER STRATEGY document released for comment and objections which may be submitted until 15th March 2019. Find it at http://www.bit.ly/ShMeCCTstrat19. Let your voice be heard.

To otherwise remain informed you may check the following items weekly.

• City of Cape Town weekly “Water Dashboard“, to be found here.
• Our 7-day & 24-hour weather report here shows probable rain in Boland dam catchments.
• SA Weather Services current Synoptic Chart here showing the currently developing weather.
• Look at our supporting current monthly report here.