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Young Hughie's great dam assignment

 
This page contains a news story about school-kid Hughie Ponifasio and his super-interesting investigation in to the Whangarei Water Services.
Updated: 8/06/2020 9:02 a.m.
Picture of Hughie with his diagram of the Whangarei water systems.
​Hughie Ponifasio shows his water-system diagrams

​A highlight for Whangārei’s Water Services Department during the COVID-19 period was the chance to make it memorable for seven-year-old Hughie Ponifasio from St Francis Xavier School.

The team has been battling the drought for many months this year, and were delighted by the following letter they received from Hughie. They responded with letters answering all his questions and invited him for a one-on-one tour of the Whau Valley Dam and treatment plant after lockdown.

They were also impressed by his slide show and detailed charts that showed how water is stored at the dam, processed, delivered as drinking water, then collected and processed as waste water.

Water Services Manager Andrew Venmore also liked his new title bestowed by Hughie, “The Dam Boss.”

Here’s Hughie’s letter:

Dear Water Scientists,

My name is Hughie, I’m 7 years old and I’m very interested in Whau valley dam. I normally go to St Francis Xavier school, but I’m at home on lock down.

I am working on a project about where the water in Whangārei goes after we use it. We visited the Kioreroa road walk ways & Whau valley dam. I also used google maps to zoom in for a closer satellite look at things. I have some questions for you.

I went on a walk at the Kioreroa road walk ways and ponds near Lime burners creek. I saw some little sucking hole/pipes in the pond - where does that water go? I also read about UV lights at the waste water treatment plant on your website. I would like to know where are the UV lights? What do they do and what do they look like?

We also went for a walk to Whau valley dam. What does the giant plug hole at Whau valley dam do? Where does it go? When was it last in use?

What are the gutter/drain things on the grassy sloping side of the Whau valley dam for?

How does the water get into and out of the dam?

(I couldn’t see those parts!) I thought maybe rivers in the bush partly fill the dam? The water isn't high enough to reach the plug hole to let the water out, so maybe at the bottom of the tower something is sucking the water out? I could see the water moving there…

What is the weird metal mushroom shaped piece of equipment near the plug hole for, and why is it too dangerous for people to go on the bridge? (to the tower in the dam?)

Why are you building a new water treatment plant? We saw the construction site on the drive to the dam.

I was also worried that the dam was very empty. Thank you for your time reading this message, please answer my questions if you have time. 

Much appreciated,

From Hughie

Has this letter got you curious, too? Here are the answers!

Where does the water from the Kioreroa Road ponds go? Out to the nearby Limeburner's Creek, then it finds its way to the harbour.

The UV lights at the Waste Water Treatment Plant are inside: we have one system (low flow) with 160 lamps and one system (high flow) with 512 lamps, each lamp is 250 watts and delivers UV light at a wave length of 254nm, the UV at this intensity destroys the DNA of the microorganisms.

What does the giant plug hole at Whau valley dam do? This is the Bellmouth spillway.  When the dam is full any extra water flows over here and through the dam and down the Wairohia Stream to the harbour.

How does water get into and out of the dam? There are 2 streams that feed into the dam plus all the rain that falls in the catchment area. There are 3 inlet pipes on the tower to take the water away.  The top one is now out of the water because the water level is low.  We are taking water from the second one at the moment.  The lowest one is right at the bottom of the dam.  The water moving you saw is because we pump air into the water to keep the Oxygen level up and to stop algae growing in the lake.

What is the weird metal mushroom shaped piece of equipment near the plug hole for, and why is it too dangerous for people to go on the bridge? (to the tower in the dam?). The metal mushroom is a small bellmouth spillway which allows us to keep the dam level lower.  This would provide more storage so that in a heavy rainfall  event like a tropical cyclone we could keep more water in the Dam and prevent the centre of town from flooding. We don’t use it because we need the extra water. It is too dangerous for people to go on the bridge because it is 20m from the bridge to the bottom of the bellmouth spillway.  Also people like to throw things down the spillway which can damage it.

Why are you building a new water treatment plant? The new treatment plant that is being built will be able to treat more water than the old plant.  It will also use new technology and should be more reliable too.

Thanks for asking these great questions, Hughie!

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