Rain and storm for Cpt pt 2

AndyT1 said:
Extract from the CoCT Weekly Water Dashboard .....

View attachment 1740723
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Worth reading in full. I wasn't aware that report was updated already: https://resource.capetown.gov.za/do...ity research reports and review/damlevels.pdf
Note that agriculture is allocated 200 million m^3/year, most of which is used during summer.

Right at the bottom, the year on year rainfall (Wemmershoek at end of June) was significantly below average. Yet the dams are full:
1. The starting level at the beginning of winter is critical.
2. Rainfall in the mountain catchment can be higher than at lower elevation.
3. A lot of rain in one week produces more runoff than the same amount spread over a month.
 
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On the subject of rain, or further rain likelihood for next few days ....

Forecast: Today none, Tuesday less than 40/50% avg probability so many places might just get some occasional drizzle or none, Wednesday even less likely than Tuesday, but Thursday looking at 80% for moderate showers in the early hours and then 50% possiblity later.
So more cloud than rain until Friday, don't think the soil could have dealt with another week of heavy rain, but dams are once again at healthy levels after a v dry May and June.
 
MirageF1 said:
On the subject of rain, or further rain likelihood for next few days ....

Forecast: Today none, Tuesday less than 40/50% avg probability so many places might just get some occasional drizzle or none, Wednesday even less likely than Tuesday, but Thursday looking at 80% for moderate showers in the early hours and then 50% possiblity later.
So more cloud than rain until Friday, don't think the soil could have dealt with another week of heavy rain, but dams are once again at healthy levels after a v dry May and June.
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I hate percentage rainfall forecasts, but clearly the amount in millimeters is going to be less than last week. The dams are fine, but high groundwater levels means more flooding is likely. Hopefully a few stormwater drains can be cleaned by then.

P.S. Yesterday I saw the council putting hot tar into potholes in the pouring rain. Clearly not a long-term solution, but at least they are trying.
 
Gordon_R said:
I hate percentage rainfall forecasts, but clearly the amount in millimeters is going to be less than last week. The dams are fine, but high groundwater levels means more flooding is likely. Hopefully a few stormwater drains can be cleaned by then
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Truth is neither % nor mm mean much in an area as large and topographically diverse as CT. Far too much variability.
Anyway those numbers where for likelihood of any rain, not amount, which is probably a reasonable prediction average, time will tell over next few days.

Gordon_R said:
P.S. Yesterday I saw the council putting hot tar into potholes in the pouring rain. Clearly not a long-term solution, but at least they are trying.
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True, I'm sure the low lying areas of Cape Flats and locations need it even more desperately but let's not even go there...
 
MirageF1 said:
On the subject of rain, or further rain likelihood for next few days ....

Forecast: Today none, Tuesday less than 40/50% avg probability so many places might just get some occasional drizzle or none, Wednesday even less likely than Tuesday, but Thursday looking at 80% for moderate showers in the early hours and then 50% possiblity later.
So more cloud than rain until Friday, don't think the soil could have dealt with another week of heavy rain, but dams are once again at healthy levels after a v dry May and June.
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Good old synoptic charts are still useful. A weak front on Tuesday, a stronger one later in the week:
ma_sy_20240715_1200.gif
 
Gordon_R said:
Worth reading in full. I wasn't aware that report was updated already: https://resource.capetown.gov.za/documentcentre/Documents/City research reports and review/damlevels.pdf
Note that agriculture is allocated 200 million m^3/year, most of which is used during summer.

Right at the bottom, the year on year rainfall (Wemmershoek at end of June) was significantly below average. Yet the dams are full:
1. The starting level at the beginning of winter is critical.
2. Rainfall in the mountain catchment can be higher than at lower elevation.
3. A lot of rain in one week produces more runoff than the same amount spread over a month.
Click to expand...
3) the only problem with this amount of rain is the damage is causes- top soil lost, erosion dongas created, towns cut off (citrusdal), roads damaged and railway lines destroyed etc
 
Rocco1 said:
3) the only problem with this amount of rain is the damage is causes- top soil lost, erosion dongas created, towns cut off (citrusdal), roads damaged and railway lines destroyed etc
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Oh, I agree it was bad. Just trying to correlate an above average rainfall event, with an incredible amount of runoff. And justifying my underestimated prediction of dam levels.
 
Managed to get some golf in today.

The greens at Burgundy were a bit slow, and dirty with sand, but still needed only 17 putts on 9 holes.
 
FiestaST said:
My washing is out doing its thing.

In US & Canada practically all folks use a dryer, washing lines don't exist, that's a no from me.

(If you have limited sunlight then it will have to do).
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yup. Driers are for emergencies only. Tuff if the washing piles up - we get enough sun even in winter to deal with it. I can understand that in countries that are snowbound for many months that driers become a habit and probably get used even if it is not really nec.
 
Tinuva said:
however was not normal.
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Not the normal you have experienced, but for us old timers, this latest spell was more like what we were used to in the late fifties and sixties. Even the flooding -- but then there were not these vast wetland areas covered in houses and shacks and infrastructure that could be damaged. And as someone has said, there was much more land available to soak it all up.
Mankind is generally pretty good at creating his own disasters by ignoring the natural lie of the land and building and occupying areas in floodplains and the bitching and moaning when nature comes along and shows us all who actually runs the show.
 
Geoff.D said:
It is a pity this graph does not keep the 2015/2016/2017 plots on them as a reminder to everyone of how dire the situation was back then.
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The graph gets a bit cluttered after 7 years. Fortunately Wikipedia has immortalised the 2016/17 drought:
800px-Cape_Town_water_crisis_graph.svg.png
 
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