GENESIS EXPLANATION FOR LAST SATURDAY FLASH FLOOD:
Hi Ross,
Following on from my phone call on Monday, please find below a response to the concerns raised on your blog regarding the Tongariro River flood event on the weekend. I would also like to reiterate my offer from this time last year that for any future concerns, you may contact me directly. That way, we can respond to any issues straight away rather than a few days later once news of your blog has reached us.
As discussed, the rainfall that fell preceding this natural event was in the vicinity of 30 mm over this period. While this isn’t a large rainfall event, the catchment was already wetted from rainfall during the week, so the river responded quickly.
The attached hydrograph shows flows in the Waipakahi River (red line) and Tongariro River at Turangi (black line). The horizontal axis shows 1 hr increments from 3 am Saturday morning to 2am Sunday morning. As you can see, the rainfall resulted in a sharp increase in flows on the Waipakahi River (a natural catchment not affected by the Tongariro Power Scheme) from 20 m3/s to 115 m3/s in 1 hour. You can see this rapid increase in flows is replicated on the Tongariro River at Turangi an hour later, where (due to the location further down the catchment), flows increased from 40 m3/s to over 200 m3/s over 1 hour.
As previously discussed, Genesis Energy has limited ability to control or affect flood flows on the Tongariro River. The Poutu Intake (which takes water from the Tongariro River and transports it to Lake Rotoaira via Poutu Canal), has a maximum consented water take of 80 m3/s, and can typically only take 65-70 m3/s. When flows in the Tongariro River (at Poutu Intake) reach 160 m3/s, Genesis Energy is required to close the Poutu Intake. This prevents the transport of Tongariro River sediment to Lake Rotoaira and is a resource consent requirement. The closing of Poutu Intake is a staged automated process, occurring over a 1.25 hr period. This staged closing of the intake ensures that there is no sudden increase in natural flows. This essentially means that when the Poutu Intake is taking water, Genesis Energy is moderating the natural flood flows in the river. Once the river reaches 160 m3/s, the natural flow of the river is allowed to flow past the intake once it has been staged closed. The increase in flows you experienced on Saturday were well in excess of any storage capacity on the Tongariro Power Scheme.
Genesis Energy has the utmost respect for river users and takes the safety of all stakeholders very seriously. We have numerous controls in place around the scheme to help manage safety, such as the provision of publicly-accessible hydrology data on the Genesis Energy website (https://www.genesisenergy.co.nz/rivers-lakes-rainfall), and a Flow Phone (07 386 8113). I note that the flow data on the Genesis Energy website shows current flows in the rivers around the Tongariro Power Scheme. These are not forecasting tools, and river users should look at rainfall graphs (also available on our website) and weather forecasts to make decisions about whether it is safe to enter the river. The peaky nature of flows in the Tongariro River mean that the river can rise very quickly under natural flood conditions, and it is important to look at rainfall and forecasts for the headwaters of the catchment, not just in Turangi. As you know, it can often be raining in the headwaters of the catchment but not in Turangi, which will affect the river flows.
I hope the above information is useful in explaining the natural rapid river increase on 28th May. As I mentioned on the phone, I would be more than happy to show you the Poutu Intake to demonstrate the little ability Genesis Energy has to control flood flows in the river, or to answer any remaining questions you may have. In the future, please don’t hesitate to contact me directly with any queries or concerns and feel free to pass my contact details on to other members of the fishing community who may have similar queries.
Kind Regards
Craig
Craig Brown | Environmental Lead – North Island
Genesis Energy | Private Bag 36, Turangi, 3353
M. 021 230 4993 | DDI. 07 384 7241 | genesisenergy.co.nz
facebook/genesisenergynz
Thank you Craig.
I am sure all the inconsiderate unhappy dissatisfied soggy anglers now understand?
Yeah right…
TRM have seen the same explanation for years. Anglers (aka stakeholders) know there is no point in complaining directly to Genesis. They are never at fault. Anglers still complain to TRM as they know we will listen or that is where they are usually staying – to recover after their dunking..
Perhaps it also says something about Genesis PR communication skills…
TRM have again run Genesis’ explanation past local anglers but they do not accept it. They never have and never will.
They reiterate to TRM again – it is such basic simple logic really. Any hydro power business operating system that puts lives at risk should be reviewed and modified or removed. The interests of river users should be placed ahead of $$$.
Everyone understands that – except Genesis. Once again, TRM anglers have asked us to reiterate the ideal solution for Genesis. i.e. Close down all the Tongariro dams and return the river to natural flow. Then you will not be liable next time an angler gets trapped.
As we have repeated now for over ten years – one day someone will not be so lucky as Graham Carter who just managed to escape on the weekend.
Genesis have been prepared to take that element of business risk and so far may have won. Anglers – aka stakeholders – are not prepared to.
If, as Genesis suggest: “The increase in flows you experienced on Saturday were well in excess of any storage capacity on the Tongariro Power Scheme.” then the power scheme should be shut down and removed as it is simply too dangerous to river users. But we understand Genesis have to put profits ahead of human life. There is no sense of corporate responsibility. They call it “business”? We call it lunacy.
Naturally they claim: “Genesis Energy has the utmost respect for river users and takes the safety of all stakeholders very seriously. We have numerous controls in place around the scheme to help manage safety….” The evidence is there that their systems do not work. Every season anglers are still put at risk. If it looks like heavy rain in the catchment and run-off might exceed 160 cumecs then it should be Genesis’ responsibility to ride up and down the Tongariro river bank to warn anglers before or as soon as they close their canal. They have never been seen patrolling the river when it floods.
Surprisingly and so disappointing, again there was no mention in Genesis’ letter of Turangi’s proposed new tourist attraction – the Cave of Mordor? Their refusal to even consider it is why anglers need to appeal to a higher authority. (Nor any exclusive contract to TRM? SWMBO will be relieved.) They must be in denial? Genesis must be making so much $$$ out of their power station they can walk away from potentially $1M p.a. for doing nothing more but just allowing tourists access.
Thank you for all the support. (I tried to go fishing yesterday but spent most of the time bailed up by angry anglers who were most encouraging about TRM’s reporting on Genesis. Genesis have no idea how much they upset locals…) i.e. following letter from a West Island angler received yesterday:
“Thank you for pointing out what in my opinion has been the single greatest detriment to the tongariro river; the reduced flows.
Historically the river’s claim to fame, apart from the size of the fish, was as a southern hemisphere surrogate for the (medium) large freestone steelhead rivers of the pacific northwest and the salmon rivers of the north atlantic.
Where one had the landlocked equivalent of an anadromous run into a river with large, and especially, wide pools demanding long casts to cover the lies. One needs no more than a superficial acquaintance with north american “spey” blogs to divine their enrapture and evangelism over “swinging” flies, and even allowing for their mode of expression, I think that is quite true. When fishing for running trout (or salmon) nothing beats a hook up wide out on the swing. The wider the better.
To a large extent that’s all gone now on the tongariro. Particularly the lower river; where once there was a reasonably long cast toward the far bank now just roll casting out the head puts your fly in the opposite vegetation.
Accompanying that is, I believe, a marked reduction in holding water or lies for running fish.
If one takes the time to trawl through the advocates reports etc. there is a lot of interesting material.
Mention is made of NIWA and Cawthron opinion that reduced flows have benefited the river. It seems to me that that is based solely on argument as to the capacity of the main river to produce/sustain juvenile stock (which is also contentious and ignores tributary streams) and fails to consider availability of holding water for running fish and the method of their pursuit.
Your material on the Elwha experience is encouraging.
The Olympic peninsula has some association with NZ.
I think Doug Rose (The Colour of Winter) references the NZ term “quinnat” salmon as deriving from chinook stock obtained from the quinault river.
And when one reads about Syd Glasso using lead based paint to try and create a more dense/faster shooting head there are similarities to early 70’s tongariro anglers with nothing much more than wet cel II
As a fellow “true believer” “keeping the faith” your recent post has spurred me to look at buying Genesis Energy shares with its opportunity, to scramble the metaphor somewhat, to be “inside the tent and pissing in”.
Cheers
AB Hobart”
9.30 am Update – another email received:
Hi Ross, Keep up the good work. Genesis response is BS.! If Genesis do not open the underground power station for tourists then they do not want to be a good corporate citizen. JT