Council Agenda - Kangaroo Island Council - SA.Gov.au

Question 2:
Given Council was briefed at the May 2012 workshop by its engineers through a ‘power
point’ presentation, of the consequences and risks associated with a dam (detailed within
Sheets C08 & C11) being sited at the end of Cheopis Street, on what basis was this site
chosen in preference to the recommended location on the top of Binneys Track shown on
2008 Layout
Plan: (http://www.kangarooisland.sa.gov.au/webdata/resources/files/Penneshaw-CWMS-
Scheme_Layout-2008-August.pdf ) and other alternative sites identified by the consultant
Answer
The site was preferred by Councillors as it represented a compromise between the costs
associated with the original Binneys Track proposal (the issue of vertical lift and the
ongoing high costs of pumping effluent up to this site were raised by Councillors during the
early assessments). The other alternative site to the south of the Golf Course has issues in
terms of visual amenity, cost of land, proximity to watercourse etc. A report in the July
Agenda discusses this further.
Question 3:
Have the risks of siting an earth dam on land above and close to the residential area and
issues related to earthquake-induced liquefaction (which is a common cause of earth dam
failure) been taken into consideration and factored in the designs and the construction
costs of the dam shown on Drawings-Sheets C08 & C11 If so, why does Council need to
conduct a further assessment on the designs and analysis of dam break risks
Answer
Yes it has – our Engineers would not have suggested the site and the design if they had
not assessed these issues as being minimal. They have made it clear that detail design
work would formally address any risk associated with the topography, tectonic, precipitation
activity and other land based parameters. However, there have been repeated suggestions
implying that a lagoon in this location would present major issues despite no facts being
made available to substantiate this. We have maintained that once the facts are
established, these perceived risks will either be validated or dismissed. Council will make
its own assessment of the advice it receives and will resolve whether to proceed with this
site or not at this time.
Given the repeated suggestions implying that the design is in some way unsuitable,
Council determined in April to formally request that this work be carried out in order to bring
facts to the fore as soon as possible.
Question 4:
If the matter in ‘Question 3' above was overlooked, why should this Council need to pay
extra consultant fees for further advice on the ‘probabilities of damage to an earth wall due
to earthquakes’ as directed by Council in ‘Resolution 20.1’ of April 2013 meeting
Answer
As above. Due to the continued suggestions implying the design is unsuitable Council
determined to specifically request additional work be done before the rest of the project is
completed. At this stage we have not been informed whether this work will attract additional
fees or otherwise.
Kangaroo Island Council – 10 July 2013 Agenda 6