She and her husband Chris have managed the camp for four years. Last summer a blue-green algae bloom meant popping a manu was off-limits for a month.
“They weren’t even allowed to go kayaking,” she says.
The water looked okay, but somewhere, either above or below them, a sample had shown potentially toxic blue-green algae. The health warning stating a risk of rashes, stomach upsets, asthma and hayfever attacks as well as possible neurological effects, added up to water too minging to manu in.
The river lake is at the end of the Taupō end of the river, which is supposed to have lower levels of nutrients in it, but the Muirs say even at the pristine end of the river, there are problems which point to high levels.
Stand on the banks of the island for a few minutes and rafts of lake weed slowly drift by. If the raft hits a snag, it starts banking up. Campers think the weed is gross, she says, but it also poses a safety risk.
“Weed definitely hinders us a lot when you are kayaking and swimming, because you can get tangled up in there.”
In the camp’s winter off-season the weed isn’t too bad, come summer when the camp is in full swing, it’s a different story.
“Depending on the summer, and how hot it's gotten, it can sometimes get to 70 to 80 percent coverage here. It's pretty disgusting.”
The lake weed and water lilies, which are also choking up parts of the lake where the current is sluggish, get sprayed once a year by power company Mercury who run the dams on either end of the lake.
The Muirs have noticed other changes. Chris’s parents ran the camp when he was a child, so he’s known the lake for decades, says Keziah.
“When Chris was a young boy, there was freshwater crayfish - kōura - in the lake. Whereas when we came, we could not see a single one. Normally, you can see the little red eyes at night when you shine a torch, but you cannot see a single one.”
The Muirs hope soon they’ll know more about what’s happening in the lake. Today Chris climbed one of the taller trees on the island, stringing cables to a 3 metre high communications pole connected to a water monitoring unit.
The pole will transmit results from the monitoring unit so it can be viewed in real-time on a website. Once it’s up and running, Chris plans to include it in what children learn about when they visit the camp. “I think it's a really good idea to tell them actually what we're doing and just the potential of being able to improve our lake.”
Among other things, the UV spectrometer in the monitoring unit detects chlorophyll, nitrate, and drivers for the growth of weed and algae.
The installation of the unit is thanks to Rob Dexter from DCM Process Control. His company specialises in water monitoring and his thirst for information has earned him a nickname.
Dexter installed the unit at his own cost. It’s one of four he’s put up and down the river, sweet-talking local landowners into allowing him access, and footing the bill for the small amount of electricity they use.
This is very different to how the councils usually monitor the river. They take water samples from different locations once a month and analyse them. But what’s been happening in the river on all the other days of the month remains a mystery.
It’s this real-time monitoring which could be a gamechanger.
Dexter says data from a similar unit owned by Hamilton City Council showed one day and one week spikes of nitrates. These would be missed if the monthly sample wasn’t taken during the spike.
Hooking up several units can show whether what happens upstream impacts downstream readings.
A unit at Orakei Korako showed high nutrient readings for several days but these didn’t show up downstream at his unit at the Cambridge golf course.
“That tells us that the nutrients were taken up by the river system enroute.”
Dexter’s not an ecologist and doesn’t profess to know the answers to fixing the river, but he hopes the huge amounts of data the units collect will be useful to others. He’s providing it to the Waikato Regional Council.
