Im supposed to be carrying stuff out to the shed from the house. That clearly isnt happening.

The tarp covering up the hole where the chimney was is holding up well.

Might go do some more cleanup in the shed a bit later, but yeah its crazy hard at times.

It bucketed down for about 10 minutes here (Whakatane) just before midday, but now it's sunny. Go figure.

Its been stopped for ages on the shore, driveway is all dried out. Not game to cross the lawn yet tho.

darylblake:

Very Heavy rain here, flooding problems starting to get a lot worse in Auckland.

I wonder how everyone is faring. Personally I am sick of being stuck in side with kids getting a bit bored.

joker97:

darylblake:

 

Very Heavy rain here, flooding problems starting to get a lot worse in Auckland.

 

 

 

I wonder how everyone is faring. Personally I am sick of being stuck in side with kids getting a bit bored.

 

Has building of buildings superseded development of hidden infrastructure like stormwater drainage? Or is it unrelated?

You could build infrastructure to cater for rare events, but thats extremely expensive and inefficient. Should the NI weather keep repeating itself, then get the digger out to run bigger outflows.  

We had a massive influx of water to our little creek, turning it into a 30m wide riverbed at least 2.5m higher than it is usually (Tuakau) and flooding my bottom paddock.

Road flooding on Tuesday was caused by culverts becoming blocked with someones tree trimmings left too close to their edge of the stream, and the subsequent weeds snarling on branches up to 10cm in diameter criss-crossing the double 60cm culvert entrance. Council digger and truck cleared and removed the debris by Wednesday and the huge rainfall this weekend went straight through without any issues to the road.

My own concrete bridge however now has about 6m3 of weed and debris blocking it as I don't get much opportunity to work on it during the weekdays and only managed to clear half of it from Tuesdays inundation... no way on earth to clear it now without a digger/tractor so will have to see what the next 6 weeks has in store while all that weed rots out and I can eventually get to the branches holding it all together :(

*edit spelling

By the looks of it, will know more next week, the event in Auckland may have been at the 1% AEP event level which is commonly known as the 1 in 100 year storm.  In contrast, the standard reticulation system used in the road network is designed to handle the 1 in 5 to 1 in 10 year event.  Surprisingly handled the event well over all, despite the localised issues out West.

The street we are off we had a car floating as it is the low point for the area and had significant flooding!

The 1 in 100 year storm is what you pay for now days supposedly. The problems are poor execution, and existing infrastructure. 

The biggest issue with stormwater, is it tends to always end up in the same spots. And they get really bad. Generally it doesnt matter if the drainage in that area is good, it usually gets so overwhelmed from a heavy dump that it causes minor flooding at the least.

The rules for designing stormwater systems make you allow for overland flow paths. So when you have rainfall that exceeds a 1 in 100 year event. You don't get major flooding. The fact that a lake appeared in New Lynn means most likely someone stuffed up. Especially as the council redid that section of road not too long ago.

Looks like more work for lawyers because of this.

They really shouldn't call these things 1 in 100 year events, because it gives peoples false sense of security. It is better IMO to say that there is a 1% change of it occurring in any given year.  You can also as a result get 1:100 year flooding multiple times within a decade. Even in conservative years. The are many towns who's rivers will flood in a 1:100 event, but because people think that the odds are low enough for it not to be in their lifetime, they spend money building protection, such as stop banks. It has been proven to be very costly for some tiwn who had planned to build them, but didn't because they thought the risk was so low.

We don't call them by that old term, we use AEP; annual exceedance probability which uses percentages.  The current SMAF requires calcs for 0.5% AEP which equates to the old 1 in 200 event I believe, and most of new lynn and green bay/Titirangi North is in SMAF areas.  Basically old drainage systems, limited discharge points and developers refusing to deal with their own drainage and discharging to the road.

Overland flow paths are a necessary evil in NZ as we do not have the finances nor existing infrastructure to capture more water in to the network.  As MattWNZ points out, the risk is so low that developers refuse to entertain the idea and a lot of people are in floodplains but do not know it, especially those that haven't had the house more than 15 years or so.

Drove to whangarei Saturday morning and came back in the afternoon. We didnt see any floods at all. A few wet paddocks but nothing in the usual places we would always see in a storm(Done the trip 500 times plus) Minor damage to road surfaces and no slips. I was wondering what this monster storm was about, Given i was yet to see a flood around Albany to Devonport and on the trip north. Feels a little over emphasized.