By 'coincidence', I saw the contractors cleaning out the local drains in our area (Thorndon) around 9:30am this morning 😌

KiwiSurfer:

 

I do agree though with drain cleaning. 

 

In Nelson (some years ago), the council stated that cleaning drain grates before storms was residents' job, not the council's.  Seriously? Which residents? There are dozens per drain grate on most suburban streets.   

I personally think homeowners of new and existing homes should be required to install stormwater detention tanks, where possible.  Perhaps 10,000L per dwelling for new and 20,000 for existing.  If my maths is mathsing, that would take 50mm of rain from a 200m^2 roof footprint.  New subdivisions should have to have separate detention ponds for another 100mm.

We should all be trying to improve the water absorbing capacity of our soils.  Deep aeration. Incorporated organic matter etc.

Of course ... sometimes rain is just set to bible-mode and there is nothing we can do about those events.  But if could shave off 150mm through detention that leaves less to cause havoc.

MikeAqua:

 

I personally think homeowners of new and existing homes should be required to install stormwater detention tanks, where possible.  Perhaps 10,000L per dwelling for new and 20,000 for existing.  If my maths is mathsing, that would take 50mm of rain from a 200m^2 roof footprint.  New subdivisions should have to have separate detention ponds for another 100mm.

 

Auckland Council already requires stormwater detention tanks for at least some new builds - this was certaintly a requirement for our new build a few years ago. Not sure if there certain conditions that needs to be met before that requirement goes into effect however. I guess the issue the becomes how to 'backport' this requirement back to exisiting houses. My in-laws place 1970's house next door also has stormwater detention tank only because that was a requirement for subdividing their lot into the two lots (one theirs and the other ours) we now occupy so Auckland Council does seem to try and enforce this to existing properties when they are able to attach newer requirements to new consents.

It'd be interesting to know if this is the case in Wellington.

I was talking to a plumber a couple of years ago who said something to the effect that new houses in my area of Wellington require storage tanks for waste water, as the system around where I live is at capacity at times. I vaguely remember sewage goes into a tank and is pumped out at night, or something like that.

Eva888:

 

Both Island Bay shops and Newtown shops flooded. We used to have one of the best wide boulevards in Wellington for years, wide enough for cycles, busses and cars, until Council decided to wreck it and make cycle lanes and a narrow road with extended footpaths in the shopping area. They changed it about four times adding more seal on to the road each time which raised it causing a hump in the middle of the road so now the water from the hump rolls down into the shops unimpeded by any decent drains. 

 

The 'improvements' to the shopping area without enough drainage means the brand new refurbished shops are filling with water even on a mildly rainy day. One poor chap just started his new business and all the fittings and carpets ruined many times. All this means Insurance goes up for all of us, thank you Council.  Climate change my foot. Bad design even a toddler with Lego could improve upon. 

 

In my lifetime I have never seen a flood at the hospital. Now in front of it the Council built an extended footpath/bus stop, with a cycle lane that commuters need to stand on while boarding a bus and become instant targets for the scooters and cyclists whizzing at them. These new extended footpaths don’t have adequate drainage either. Oh dear blame climate change again, never blame the blocked unmaintained drains, or new 'improvements' with runoff calculated incorrectly for sufficient drainage to incorporate all the new flats going up everywhere and new footpaths over old drains.. 

 

Most countries have a cleaning maintenance programme especially in late Autumn because of falling leaves, not our Wellington Council. The only time they clean drains is if Karen calls them to report a blocked drain flooding and she’s screeched loud enough. 

 

I’ve got plastic bottles and rubbish in a badly installed drain in the gutter front of house, where if you happen to stand getting out of a car, your entire leg will go down the huge gap into it. You’d definitely lose a small unleashed dog there or snap a kids leg. Reported umpteen times, no one fixes it. Large items get blown into it blocking a major storm water drain. If it floods…it’s that pesky climate change again and up goes insurance for the entire street. 

 

Councils do your job properly with timely, coordinated  maintenance and designs fit for purpose. 

 

 

 

This is what happens when Wellington votes for the greens . Same in Lower Hutt no drainage on theses cycle lanes 

Agree with @Stu1. Our last Mayor was a nightmare - plenty of excuses no action and decisions led by the unelected, wet behind the ears Greens within Council, most of whom are still there, so don’t hold your breath. You never get what you vote for. 

Eva888:

 

Most countries have a cleaning maintenance programme especially in late Autumn because of falling leaves, not our Wellington Council. The only time they clean drains is if Karen calls them to report a blocked drain flooding and she’s screeched loud enough. 

 

The councils were forced to get rid of their civil works departments by central government and employ contractors. Fine in theory but I recall flooded roads throughout the Wellington region a few years ago and all the available suction trucks were in Palmerston North clearing the flooding there.

I can think of numerous sites in Wellington that wouldn't need a call from Karen, just a note on the calendar. Pohutukawa if the roots don't get you the leaves will.

MikeAqua:

 

KiwiSurfer:

 

I do agree though with drain cleaning. 

 

 

In Nelson (some years ago), the council stated that cleaning drain grates before storms was residents' job, not the council's.  Seriously? Which residents? There are dozens per drain grate on most suburban streets.   

 

I personally think homeowners of new and existing homes should be required to install stormwater detention tanks, where possible.  Perhaps 10,000L per dwelling for new and 20,000 for existing.  If my maths is mathsing, that would take 50mm of rain from a 200m^2 roof footprint.  New subdivisions should have to have separate detention ponds for another 100mm.

 

We should all be trying to improve the water absorbing capacity of our soils.  Deep aeration. Incorporated organic matter etc.

 

Of course ... sometimes rain is just set to bible-mode and there is nothing we can do about those events.  But if could shave off 150mm through detention that leaves less to cause havoc.

 

We actually submitted a public  submission to our local council when they went out for submissions on creating a whole new residential zone. We said requiring each house to have their own 10,000L underground tank, which was a requirement of some other subdivisions. . The council basically ignored it saying it was outside their scope. The cynic in me thought that they didn't want to add to costs for developers, but it is really false economy to do so, because there are always water shortages in summer where water usage for gardening gets restricted. My impression therefore is that councils can be pretty lazy and they mainly act reactionary, rather than being proactive. I find many breaches of bylaws etc require the public to report them, rather than council staff to proactively act. For example I saw advertising signs on public verge, obstructing  drivers views, and had been there for months. Council staff had driven past it many times, but no one did anything until I actually reported it. They seem to work with tunnel vision, and not outside the scope of what each individual does. Maybe it is so they don't rock the boat, I don't know. But my brother worked for a council for about 10 years and he hated it and said it was so slack and so much money got wasted and he didn't want to speak out because it was in the culture to just get on with their own work with their head down.. 

mattwnz:

 

We actually submitted a public  submission to our local council when they went out for submissions on creating a whole new residential zone. We said requiring each house to have their own 10,000L underground tank, which was a requirement of some other subdivisions. . The council basically ignored it saying it was outside their scope. The cynic in me thought that they didn't want to add to costs for developers, but it is really false economy to do so, because there are always water shortages in summer where water usage for gardening gets restricted. 

 

Water storage is useful but that is separate from detention tanks.

mattwnz:

 

MikeAqua:

 

 

 

In Nelson (some years ago), the council stated that cleaning drain grates before storms was residents' job, not the council's.  Seriously? Which residents? There are dozens per drain grate on most suburban streets.   

 

I personally think homeowners of new and existing homes should be required to install stormwater detention tanks, where possible.  Perhaps 10,000L per dwelling for new and 20,000 for existing.  If my maths is mathsing, that would take 50mm of rain from a 200m^2 roof footprint.  New subdivisions should have to have separate detention ponds for another 100mm.

 

We should all be trying to improve the water absorbing capacity of our soils.  Deep aeration. Incorporated organic matter etc.

 

Of course ... sometimes rain is just set to bible-mode and there is nothing we can do about those events.  But if could shave off 150mm through detention that leaves less to cause havoc.

 

 

We actually submitted a public  submission to our local council when they went out for submissions on creating a whole new residential zone. We said requiring each house to have their own 10,000L underground tank, which was a requirement of some other subdivisions. . The council basically ignored it saying it was outside their scope. The cynic in me thought that they didn't want to add to costs for developers, but it is really false economy to do so, because there are always water shortages in summer where water usage for gardening gets restricted.

 

councils should be doing drain cleaning. 

people can install their own detention tanks if they want. not uncommon to make them dual purpose and be a retention tank as well. it doesn't have to be 10,000 litres, it all depends on what your trying to do. there is lots of different design options.

developers don't want the added cost and in theory if the storm water design is ok, then they should not need to.

soil drainage is generally pointless with these sort of rain events. way to much rain. whats more important is overland flow paths and storage. 

Bung:

 

The councils were forced to get rid of their civil works departments by central government and employ contractors. Fine in theory but I recall flooded roads throughout the Wellington region a few years ago and all the available suction trucks were in Palmerston North clearing the flooding there.

 

I can think of numerous sites in Wellington that wouldn't need a call from Karen, just a note on the calendar. Pohutukawa if the roots don't get you the leaves will.

YES THIS. Contractors don't have the same level of interest in fixing issues and the path to resolve is complex. Take the Wellington Water situation: - Resident reports an issue to council --> council logs and passes to Wellington Water --> Wellington Water passes to contractor and in some cases contractor passes --> to sub-contractor. It's no wonder things take forever/just don't get done.

In a real example that I reported three times before it was properly addressed, I noticed the seal slumping further down our street, but no obvious water seepage and reported it via WCC's Fixit app. Got logged with Wellington Water anyway who passed it to their contractor. Contractor decided "no leak, not us" and closed it. This happened twice more, until on the third time, I followed it up with a phone call to the WCC contact centre who transferred me to an actual WCC employee who decided to come and have a look. Was fixed within a week.

tweake:

 

councils should be doing drain cleaning. 

 

people can install their own detention tanks if they want. not uncommon to make them dual purpose and be a retention tank as well. it doesn't have to be 10,000 litres, it all depends on what your trying to do. there is lots of different design options.

 

developers don't want the added cost and in theory if the storm water design is ok, then they should not need to.

 

soil drainage is generally pointless with these sort of rain events. way to much rain. whats more important is overland flow paths and storage. 

 

I think storm water management is something where there are multiple opportunities to reduce impact.  A stormwater system has a finite capacity.  It's designed for a level of event and it will be overwhelmed at some point if there is enough rain.  So residential detention tanks and neighbourhood detention ponds all reduce the load on the stormwater system. 

I've noticed where we live that 100mm of steady heavy rain will fill the neighbourhood detention pond.  That's a big chunk out of even a very large rain event.  If every house had 20,00L tank (almost no one will, unless it's compulsory) and assuming 200m^2 houses and 50% site coverage ... that's another 50mm off each section.  Well-structured soil will comfortably absorb another 50mm, so that's another ~15mm with around one third site coverage.  Total of 165mm.

But yeah, directing water where you want it to go is a huge part of that. 

MikeAqua:

 

  Well-structured soil will comfortably absorb another 50mm,

 

its all northland clay here, it absorbs a couple of mm. anything more than light rain runs straight off. tho those on the coast on sandy soils, very well draining so heavy rain is not much of an issue. 

certainly adding detention tanks will help, but that can back fire if councils take advantage of that to shortcut/undersize their own systems. eg auckland storm water was designed for 50mm (article after Gabriel cyclone) yet our houses are designed for 100mm and some of the storms are hitting 150mm. 

tweake:

 

its all northland clay here, it absorbs a couple of mm. anything more than light rain runs straight off. tho those on the coast on sandy soils, very well draining so heavy rain is not much of an issue. 

 

certainly adding detention tanks will help, but that can back fire if councils take advantage of that to shortcut/undersize their own systems. e.g. Auckland storm water was designed for 50mm (article after Gabriel cyclone) yet our houses are designed for 100mm and some of the storms are hitting 150mm. 

 

Clay is hopeless, especially on slopes but on flatish land it can be improved over time - with the right treatment and planting.

We probably need some sort of national design direction around stormwater systems.  Because you're absolutely right, councils would take the opportunity to downsize there systems in favour of detention tanks. Probably we need to design for at least 200mm, given that buildings and stormwater systems last decades.

On the new build we've designed (no council stormwater system), I've gone with a ~280 x 100mm gutter profile (basically commercial building spouting) and overdone the down pipes.  It's been a bit of a nuisance aesthetically to conceal it all, but it will be easy to keep clean and will take a ridiculous amount of rain.  It won't overflow and we'll be able to capture all that rain for non-potable use.  It's actually been fun geeking out on this part of the design. 

MikeAqua:

 

Clay is hopeless, especially on slopes but on flatish land it can be improved over time - with the right treatment and planting.

 

Clay can give you nasty surprises on slopes. At our Wellington house there was a break in the ceramic stormwater pipe. The surrounding Clay absorbed water until it took on a porridge consistency and flowed downhill. That sort of thing is repeated regularly throughout the region. If it is a council owned pipe it is always determined that "it was the slope failure that damaged the pipe" not the other way around.