Dunedin City Council (website) on Stormwater:
Stormwater is rain or snow runoff that does not soak into the soil.
When an area is developed, stormwater generally increases due to runoff from impermeable surfaces (eg roofs, roads, carparks, or compacted soil). It flows naturally from higher to lower ground, and ultimately discharges into natural watercourses such as wetlands, creeks, rivers or the sea. Land development results in the creation of both private and public stormwater systems, which collect and transfer stormwater to lower ground more efficiently. The public stormwater system is a network of drains, gutters, pipes, mud tanks, detention ponds, stormwater reserves and other associated infrastructure.
At other threads (here and here), contributor JimmyJones has cited the South Dunedin Integrated Catchment Management Plan (ICMP) to draw attention to the actual or perceived state of the stormwater pipes at South Dunedin. He believes the type of pipeways and the deteriorating condition of the pipes contributed to the June 2015 South Dunedin “flood event”, and will require budgeted upgrade.
But is the South Dunedin ICMP correct about the underground pipes and their condition?
Largely, the ICMP was a desktop assessment carried out by consultants for the Dunedin 3 Waters Strategy. Namely, Opus International Consultants and URS New Zealand (now trading as Aecom) in association with Dunedin City Council.
Read more about the 11 ICMPs for Dunedin here.
DCC says ICMPs are used for planning and management of the stormwater system. For each stormwater management area, or catchment, issues are identified and prioritised, and solutions are identified and implemented. The ICMPs are mainly in the metropolitan Dunedin area (including Mosgiel and Port Chalmers). They inform investigation and planning decisions and help focus council priorities for future operational and capital works. Implementing the ICMPs is also a key requirement of DCC consents to discharge stormwater into the coastal marine area. Further information is available on the Stormwater monitoring page, see also the Stormwater responsibilities page.
The Pipes at South Dunedin
Local water and drainage experts familiar with the stormwater system say:
Sat, 18 Jun 2016 at 10:52 a.m.
The South Dunedin ICMP report has been read, it’s “ok”. But it’s also described as “…glossy and costly for the consultant(s). Basically, such reports tell the Council stuff they neither read nor understand, but would have mostly been trivial knowledge (where accurate)” to local experts familiar with the design and day-to-day workings of the stormwater system.
“You can believe any part of [the ICMP] or not. It’s a desktop study, which speculates on pipe condition. Robinson and Hendry have read it and obviously don’t agree. Pipes last for an eternity with limited maintenance (other than blockage removal) provided there isn’t ground movement or corrosion (these pipes are concrete).”
Listener, June 11-17 2016, pp22-29 (not yet available online):
“Mr Hendry believed South Dunedin’s infrastructure, which he spent six years helping build as a surveyor in the 1960s, would have been good enough to prevent much of the damage had it been properly maintained. […] My view is that these people out here, a lot of them have got nothing. Now they have got a hell of lot less. It’s not fair on them. Nobody’s come out and said ‘we were wrong. Something wasn’t done right’.”
█ Come to the Public Meeting in South Dunedin on Monday evening, hosted by the South Dunedin Action Group.
Related Posts and Comments:
17.6.16 So we’re going to play it this way #SouthDunedinFlood
● 16.6.16 Public Meeting: South Dunedin Action Group #AllWelcome
10.6.16 “Civic administration” reacts to hard hitting Listener article
● 6.6.16 Listener June 11-17 2016 : Revisiting distress and mismanagement
● 4.6.16 Johnstone review … DCC Infrastructure Services meeting 26.4.16
3.6.16 DCC —godsakes, how did it get to this? #flood #property damage
● 19.5.16 Johnstone review of 2nd DCC report #SouthDunedinFlood
29.4.16 Vandervis emails batch 2 #Dunedin #infrastructure #flood #mudtanks
27.4.16 Vandervis emails batch 1 #Dunedin #infrastructure #flood #mudtanks
27.4.16 DCC meeting and apology NOT Enough— #SouthDunedinFlood
20.4.16 DCC Politics : Release of Infrastructure Report #SouthDunedinFlood
14.4.16 South Dunedin flood risk boosters #ClimateChangeCrap #PissOffPCE
31.3.16 DCC: Infrastructure report 2 pending —Mudtanks & stormwater…
● 8.3.16 Johnstone independent review of DCC report #SouthDunedinFlood
2.3.16 DCC compels extensions on LGOIMA requests #SouthDunedinFlood
26.2.16 Mudtanks and drains + Notice of Public Meeting #SouthDunedinFlood
21.2.16 DCC infrastructure … report (30.11.15) subject to ‘internal review’ only
● 13.2.16 South Dunedin Flood (3 June 2015): Bruce Hendry via ODT
4.2.16 2GP commissioner appears to tell Council outcome… #hazardzones
4.2.16 Level responses to Dunedin mayor’s hippo soup #Jun2015flood
30.1.16 DCC Rates: LOCAL CONTEXT not Stats —Delta and Hippopotamuses
● 25.1.16 DCC: South Dunedin Integrated Catchment Management Plan (ICMP)
19.1.16 Listener 23.1.16 (letter): South Dunedin #Jun2015flood
16.1.16 NZ Listener 16.1.16 (letter): South Dunedin #Jun2015flood
14.1.16 ‘Quaking!’ Dark day$ and tide$ to come #Dunedin #Jun2015flood
10.1.16 Infrastructure ‘open to facile misinterpretation’…. or local ignore
5.1.16 Hammered from all sides #fixit [dunedinflood Jun2015]
24.12.15 Site notice: posts removed
● 3.11.15 South Dunedin Flood | Correspondence & Debriefing Notes released by DCC today #LGOIMA
█ For more, enter the terms *flood*, *sea level rise*, *stormwater*, *hazard*, *johnstone*, *hendry*, *south dunedin action group*, *debriefing notes* or *listener* in the search box at right.
Posted by Elizabeth Kerr
Election Year. This post is offered in the public interest.