Alan McIntosh has run the Madloop Windsurfing club on Lake Pupuke for 25 years, and banged his head on the slippery rock foreshore in 2018 flooding.
Auckland Council last year held an internal discussion about draining Lake Pupuke at a cost of millions of dollars, amid fears there could be a "fatal" accident on its flooded shoreline.
Emails obtained by the Herald via official information, have revealed Auckland Council parks staff looked into the cost-risk benefitsof partially draining the Takapuna freshwater lake through a pipe into the ocean.
Pupuke occupies a volcanic crater with a circumference of about 4.5km, and became severely flooded after the winter of 2018.
Auckland Council senior parks co-ordinator Jaco Marais sent a number of emails to fellow council staff in November 2018 saying water levels could not be left too high in Lake Pupuke; a man had already fallen over and suffered a head injury.
"We had in the past week already trainer of the windsurfing club, Alan, slipping and sliding here and bumped his head after slipping on the algae," Marais wrote on November 23.
"With hundreds of kids joining the club to learn to surf, we have an obligation to provide a safe surface, which we can't if it is submerged.
"The risk is that a child could slip as well, bump his/her head which could be fatal."
On several occasions Marais highlights that there is no "contingency plan" to lower the water levels of Lake Pupuke, and that there are warning signs, but no ropes.
"But that doesn't stop an injury - not many kids reads these signs when they are out to play and learn to surf".
On November 22, 2018, Auckland Council's healthy waters manager Frank Tian emailed: "To my knowledge there is no artificial means of controlling the water level in the lake."
"I did ask our planning team to look at the possibility of installing a pipe and draining the lake water to the ocean," Tian said.
"This will cost millions of dollars and have to go through a complicated consenting process.
"Technically it is also challenging because most houses on eastern side of the lake are multimillion-dollar properties."
Last week, Auckland Council general manager of healthy waters Craig Mcilroy reiterated there was no intention to dig a pipe to drain Lake Pupuke to the ocean.
"This would cost millions of dollars, would be detrimental to the surrounding beaches and the Hauraki Gulf ecosystem and would be unlikely to get consent approval from council and iwi," Mcilroy said.
"The fluctuation of water levels in the lake is a natural process, there is an underground aquifer and springs between the lake and the sea that can cause the water level to rise."
Auckland Council head of operational management Agnes McCormack said "regular maintenance" cleared the lake's shoreline of algae "to prevent slipping".
"We are aware of the issues with flooding at Lake Pupuke and have installed signs down at the Pupuke shoreline to warn passers-by that the ground is slippery and to take caution," she said.
Alan McIntosh has run the Madloop Windsurfing club on Lake Pupuke for 25 years, and is the man referred to in council emails, banging his head on the slippery rock foreshore.
"The main thing is there's not good access points to get into the water and it is slippery. It would be better for the general public if they could put some jetties," McIntosh said.
"There's safety concerns when it [the water level] gets right up into the car park and then the car park itself gets slimy. I slipped over once and banged my head on the ground.
"The last three winters it has [flooded more]. It is a bit strange after 25 years of being here, seeing the water come up that high."
Ian Graham has been a resident on Manurere Ave, which faces on to Lake Pupuke, since 1974 and says in that time "there has never been anything like" the flooding in 2018.
"There was a sudden massive rise in the lake. Whether there has been a progressive gradual rise, I can't swear to," Graham said.
"I know I was flooded. Next door, he's lost around two metres of land. Last year it was certainly atypically high. That does sort of point to some sort of event doesn't it?"
Graham says his insurance funded the $75,000 reinforcement of a retaining wall, after his raised backyard leading down to Lake Pupuke collapsed in a mud slip.
"It's consumed my life trying to fix it, for the past year and a half."