SAFETY RISK: Issues surrounding the safety of Ewen Maddock Dam in the Mooloolah Valley have been raised.
SAFETY RISK: Issues surrounding the safety of Ewen Maddock Dam in the Mooloolah Valley have been raised. Lachie Millard

Dam safety questioned, 17000 residents in flood failure zone

THE safety of one of the Sunshine Coast's major water catchments has been called into question following the rejection of a development.

Currently sitting at 97.4% capacity, the walls surrounding the pristine waters of Ewen Maddock Dam have been identified as a safety risk and even described as "vulnerable".

The rejection of a childcare development initially propelled the issues into the public spotlight, with the Courier Mail reporting more than 17,000 residents as being situated in a "flood failure zone" on Sunday.

In documents prepared by Seqwater for the Sunshine Coast Council, Ewen Maddock Dam was labelled as in need of upgrade to "ensure it can meet relevant Queensland and Australian guidelines into the future".

It identified dam safety issues which included inadequate spillway capacity, vulnerability to a major earthquake and "no defensive design features to prevent internal erosion of the embankment material".

Seqwater prepared the documents at the request of council when considering a material change of use application for a childcare centre.

The childcare centre was proposed to be located within the existing bowls club directly downstream of the Ewen Maddock Dam wall off Connection Rd at Glenview.


In Seqwater's response to council it cautioned against approving the development.

"Seqwater is concerned that the proposed development would appear to lie within the flood zone immediately downstream of the dam resulting from large to extreme flood events," the document stated.

It also noted that although unlikely "this risk is present in both flood and non-flood events, as a dam failure may result from an earthquake outside of a rainfall event".

The Courier Mail reported that the applicant had to abandon the project after spending $50,000 and investing more than 12 months in the process.

An Seqwater spokesman said Ewen Maddock Dam was "not at imminent risk of dam failure".

The spokesman said Seqwater had been approached by council regarding the childcare centre and had advised that the proposed development was located within a flood zone.

They said Ewen Maddock Dam was one of many dams listed in Seqwater's Dam Improvement Program to be upgraded.

Stage one works on Ewen Maddock dam were completed in 2012.

The spokesman said stage two works on the dam would start by 2019.

"The upgrades are about ensuring future safe operations and increasing resilience for extreme natural disasters such as floods," they said.

"Seqwater is currently working on detailed design and approvals for the planned upgrade at Ewen Maddock Dam."