A Thames resident is concerned a council stormwater discharge pipe emptying on to the slope above her home could put her home and a popular walkway at risk of slips.
The property where Donna Pervan lives with the home’s owner Alan Kent is tucked into the hillside beside the Jacob’s Ladder walkway.
The driveway, and the steep steps, are on a road reserve or “paper road” owned by Thames Coromandel District Council. The reserve spans the hillside from the corner of Grey St and Heale streets below to Mt Pleasant Rd above.
During Cyclone Gabrielle in 2023, there was a slip behind Alan’s garage from the hillside above, within the property boundaries. Another slip, also on the property, occurred further down across the lower section of the driveway. The slips have since been cleared and retaining walls installed.
The garage was initially yellow-stickered by the council as mud and debris from the slip had piled up against its concrete block exterior, but the damage has since been repaired and the sticker removed.
But Donna was worried about further slips on the slope. The issue, she said, was a stormwater drainage pipe which ends just a couple of metres below the bench seat at the top of the ladder, discharging into the ground in the reserve.
“And [the council is] saying because the pipe runs in a straight line, that the water runs straight,” she said.
“But you can see the water, what it’s doing, seeping all in.”
Donna said she could see on the slope where the water had carved a path off to the side behind the property’s garage. She said water was also heading in the other direction, pooling under the steps of Jacob’s Ladder. The steps were beginning to list away from the hillside, she said, and she was worried they were becoming dangerous.
“The water’s getting under [the steps]… It’s all mud under here,” she said.
“It’s just a matter of time.”
Exacerbating the issue is the amount of leaf litter falling from the trees in the reserve, which Donna said was a constant source of blockages in the ladder’s drains and at the top of the walkway.
For the five years she’s lived there, she has spent a lot of time in the reserve, keeping the steps and drains free from debris.
“I’ll come down here with my blower vac and get all the drains,” she said. “Once the oak leaves drop, you’re just out here all the time because you’ve got to clean these gutters so that water can run down.”
Donna said she rarely saw workers maintaining the stairway.
“They used to come every week, but it’s all changed,” she said.
“This is what happens. They should be in here clearing all this shit out. And, of course, then [the drains] get blocked.”
The council did not respond to a Valley Profile query asking who was responsible for clearing the leaf litter, and how often it was done.
A simple way to fix the issue, Donna said, would be to extend the stormwater pipe part-way down the slope, so it discharged directly into the stormwater drain on her driveway.
But because both the pipe and the driveway were on council-owned land, Donna said she was unable to make the fix herself.
The Profile asked the council to explain whether the drainage pipe was affecting the structural integrity of the slope and Jacob’s Ladder. It replied with the following statement:
“Council’s drainage infrastructure adjacent to Jacob’s Ladder is adequate and fit for purpose. The overland flow that occurs during wet weather events for example is due to natural servitude”.
When pressed further, the council declined to respond.
However, an email from the council to Alan, dated September, 2023, said while the road drain did outfall above the site of the upper slip, it was not directly in line with the site, instead pointing down the centre of the road reserve. The email also referred to “subservient rights of discharge”.
“The road and road drainage above your property were in existence before your property was created, and I see no liability for council in this case,” the email read.
“Council has a right to discharge water downhill, and the property below has a right to accept the flow.”
Donna said the council had refused to look further into the issue unless she supplied them with her post-cyclone geotechnical report. The report was prepared for Donna and Alan in August, 2023, when the retaining walls were put in. It stated that an exploratory borehole at the top of the driveway had found groundwater not far below ground level.
“Groundwater was encountered at shallow depths between 0.4m to 1.86m bgl (below ground level) within exploratory holes. This is expected to be a seasonally high groundwater table due to the high levels of rainfall the region has experienced in the recent months,” the report said.
“Groundwater levels commonly fluctuate according to the season and rainfall events. As such, groundwater levels may vary and be identified at higher levels than monitored during this ground investigation.”
Matt Price, the contractor who put in the retaining walls at the property, said he could see the drain water flowing directly on to Alan’s land.
“They’re not fixing it properly, and that’s what’s creating a lot of the issues,” he said.
“I think that a pipe needs to come down that hill and connect it to the stormwater. It’s definitely going to get worse.”
Donna said she just wanted the council to take another look at the drain.
“It cost us over $30,000 [for the report] so why would I give it to them? They know what’s going on here,” she said.
“They need to re-divert that bloody drain.”
