September 22nd 2010
“Inept and negligent design” causes flooding in Horseshoe
For years now the residents of Horseshoe Bay’s Apjohn Street and Corica Crescent neighbourhoods have waded and even paddled their way through their streets which regularly become flooded waterways after heavy rain. Whilst the area is naturally low lying the residents believe their problems are more the result of “inept and negligent design” and, after years of waiting for Council to act, they have begun a petition and are also threatening a class action.
With recent downpours portentous of another big wet on the way, resident and retired Senior Lecturer in Electrical Engineering from JCU, Mr John Wicking, is leading the charge to get Council to act on a flood mitigation strategy which identified the problem in 2005.
“This is a negligent design and TCC have been made aware of it a number of times over a number of years,” says John who, along with another 37 petitioners, “...believe the situation has been exacerbated by Council’s approval of head works up stream of Apjohn Street causing additional water to flow down the street,” and, “Council charges headworks fees to each developer yet, even after continued written complaints and evidence, refused to rectify the situation.”
With an engineer’s eye for detail, cause and effect, John Wicking showed Magnetic Times the most glaring aspect of the problem. On Apjohn street, running down from a large pipe beneath Horseshoe Bay Road is a drain which runs past several houses while shrinking away to almost nothing. According to John Wicking, after about 150mm of rain - a reasonably common event on Magnetic Island - the vanishing drain is exactly where the mass of water from a large catchment, which reaches right back up above Horseshoe Bay road as it comes off the Horseshoe Bay hill - is directed. Inevitably, the water simply washes across the road and across the residents’ gardens.
John Wicking stands on Apjohn Street near where the drain vanishes
To dramatically illustrate exactly what happens all too often, John made a flood video which tracks the water flow from developements upstream down to a flooded Apjohn street. (here).
John Wicking believes the solution is a simple one. A large drain needs to be built on the other (southern) side of Apjohn street to carry the seasonal flows down to meet the large culvert which runs parallel to and behind Corica Crescent.
Magnetic Times sought a comment from Magnetic Island Councillor, Trevor Roberts who wrote: “There’s a number of factors which compound the problem - the narrow layout of the streets, the limited capacity of storm water drainage under private driveways, and the problem of groundwater flows after a big deluge.”
John Wicking, who has measured the widths of the streets, told Magnetic Times, “The assertion that the streets are narrow is not evident,” and, “The limited capacity of water drainage under driveways is also not evident”. He notes that after number 37 Apjohn Street, “the drain ceases to exist” and that, “The capacity of street drains is a council responsibility. There is no further drain at this point and hence, there is no further capacity”.
He is also dismissive of “deluges”, as more of a, “biblical term rather than one that can be applied to rainfall.
“Rainfalls of 150 mm will cause flooding in Apjohn St.. This can occur several times during the course of the wet season. It is not an atypical event.”
According to a letter from Council’s Infrastructure Services Department, Acting Manager Investigations, Ms CordeliaDe Kievit, to another resident, “...this area experiences extended periods of groundwater flows long after rain events have ceased and can last up to three months after the wet season. Provision for this must also be considered in any design solution.”
But, according to the letter, a watercourse down the southern side of Apjohn Street is also seen as the “best option” but will require, “new culverts under Horseshoe Bay Road and the construction of a new ‘natural’ creek or large underground drain,...and may require the acquisition of land from the adjoining property”.
Due to "significant costs" the Infrastructure Services’ claim is that they lack the funding for such work, “in the immediate future”.
Residents would likely keep their gumboots handy following the further advice that the (Apjohn drainage) works, “are being considered along with other similar drainage problems and priorities identified in Council’s 10 year capital works program”.
What riles John Wicking is that, “Council has approved, and received funds for the development of residential property upstream of the Apjohn St. water course,” and, “This water flow has been obviously directed to Apjohn Street.”
“The flooding is not caused by excessive rain as claimed, but rather by an inept and negligent design. The Council is liable to rectify this situation it has caused and perpetuates”.
Cr Roberts told Magnetic Times, “The council has developed a flood mitigation strategy for the city which investigates costs and prioritises projects across the city and I’ll be pushing very strongly for Apjohn St to be right up there.”
There seems little doubt that the residents of Apjohn and adjoining streets will be closely watching his efforts.
Story & photos: George Hirst
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