It may be raining and our gardens are looking green again but our water situation is still deep in the red.  Unless we are far more frugal with the water we have right now, predictions by weather and water specialists show a very high probability that Cape Town will run out of water by early March 2018.   How can that be?  Look at the calculations below based on current water consumption levels. (source: weather scientist, Dr Peter Johnston, UCT who admits to being cautiously conservative. Quite right too considering what is at stake.)

2017 08 water drop Q your score (5)Dam Levels as of 14 August = 31.0%   (Net amount of extractable water 21.0%)

Predicted Winter rain weekly dam level increase of 0.5-2% (say 1.5%)
Predicted Summer weekly consumption drop of 0.5-1.5% (say 1%)
Weeks remaining this Winter assuming winter rain over by spring equinox, Sept 23 = 5 weeks. Likely total dam level increase owing to winter rain:  7.5%
Usable level by Mid September 28.5% (31+7.5 less 10% )
Summer weekly consumption & evaporation drop of 1% = 28.5 weeks = 200 days
Water runs out in 200 days from 14 August on 2 March!! NO EXTRACTABLE DAM WATER! See graph comparing dam levels and water consumption at the end of the article.

Collectively we are using 630 million litres of water each day while the City’s target is 500 million litres or 87 litres per person. 87 litres of water per person for household consumption is entirely doable. The best opportunity we have to make the meagre supply last is to save as much of what we have starting from NOW.  The City has a number of expensive emergency interventions including desalination, boreholes into deep aquifers and trucking in water (from where?). The city’s intent is to drive down collective usage to 500 Mℓ/day as well as to ensure that there is always at least 500 Mℓ/day of water in production. (http://www.infrastructurene.ws/2017/08/19/cape-town-announces-water-resilience-plan/The big question is how likely, given the scale of the operations, will sufficient water augmentation be implemented in time?

We can’t wait for the City to manage this crisis so that we don’t run out of drinking water.  The inconvenient truth is that everyone can and needs to reduce consumption to below 87 liters starting now.  Many are already using less – more need to do so!  Based on the increasing cost of water to pay for the City’s augmentation projects, it also makes financial sense to be as water efficient as possible.

Every drop counts!  How do you measure up against the official target of 87litres per day?  Look at the Water Budget Table below based on using 87 litres in the left hand columns and see how much more you can save with the tips in the right hand columns.

87 Litre target Activity   How you can do better! Less litres
2 Reserve 2 litres in a bucket for hand washing Use to flush toilet at end of day. 2
0.5 For brushing teeth For brushing teeth 0.5
35 A two minute shower can use as much as 30 – 40 litres.

Catch shower water in a basin to use for flushing the toilet.

Reduce water pressure while showering. Switch off flow while soaping. Catch shower water in a basin. It is not necessary to shower every day. Wash in a basin and only use 5 – 10 litres of water. 10 -20
30 A toilet flushes between 9 – 10 litres. Three flushes per day uses 30 litres of drinking water. Flush a maximum of 2 x per person per day, preferably using shower, rain or well point water. Reduce volume of cistern by placing a 1 – 2 litre bottle in it. 16
4 Water for drinking and cooking. Water for drinking and cooking. Cook with family and friends to save water. 4
5.5 Washing dishes. Wipe scraps off the plates to reduce need for water. Wash dishes once a day. Wipe scraps off the plates to reduce need for water. Rinse washed dishes in basin and reuse this water. 4.5
6 Washing clothes 2 x per week uses about 36 litres 6 litres per day. Washing clothes 2 x per week uses about 36 litres or 6 litres per day. Use bio-friendly detergent and catch rinse water to reuse for washing floors or watering plants. 6
6 Use shower water or clothes rinse water to wash floors. Use shower water or clothes rinse water to wash floors. 6
Total 88 litres minus re-use of 30 litres of shower and 6 litres of clothes rinse water = 52 Litres of drinking water used.   50 – 60 litres minus re-use of 10 – 20 litres of shower and 6 litres of clothes rinse water = 34 – 44 Litres of drinking water used per day.

We are not the only citizens in Cape Town impacted by the drought. As summer approaches please remember the birds, lizards, frogs and urban wildlife and top up the bird baths and dishes of water for the ground dwellers.

 

Kim Kruyshaar 2017 08 20

2017 08 Daily Mavrick rain & dam levels graph of past 6 years