I asked the following questions at last month's Council meeting. You might be surprised at how much of the works has already been completed or is approved to be undertaken. The most disturbing information is that the widening and deepening of identified sections of the creek between Victoria St and Cross Rd will not be completed until 2035/36. By this time property acquisition costs will have escalated considerably and until this work is done flooding is still a significant risk in Unley's section of the Creek!
1.
What projects for the entire Brown Hill Creek catchment have been
completed so far?
Ridge Park Detention Dam – City of Unley.
BHC Diversion Culvert by DPTI – City of Unley.
Upper BHC – Hawthorn Reserve – City of Mitcham.
Mount Osmond interchange dam modification.
Currently in year 3 (2018/19) of a 20-year program to implement the flood
mitigation works.
2.
What projects for the entire Brown Hill Creek catchment are in the
planning stage?
South Parklands – Victoria Park City of Adelaide (Public consultation of
proposed works to close 5 July 2019. Construction to commence 19/20FY
and be completed 2020/21).
Page 411 of Council Agenda 24 June 2019
South Parklands – Park 20 City of Adelaide (Public consultation of
proposed works to close 5 July 2019. Construction to commence 2020/21
and be completed 2021/22).
Glenside – City of Burnside (Construction to commence as part of the
Cedar Woods development at Glenside).
Upper BHC Area 1 Wilberforce Walk (Anzac Highway to Third Avenue
only) – City of Unley Construction to commence 2019/20 following land
acquisition.
3.
What projects have been identified but are yet to be planned or completed
in Unley?
Brown Hill Creek – Creek upgrade areas (widening)
Upper BHC Area 1 (Third Avenue – Forestville Reserve)
Area 2 (Victoria Street – Mitchell Street & Orphanage Park
culvert option)
Area 3 (Douglas Street – Malcolm Street)
Area 4 (Malcolm Street – Cross Road)
Bridge/culvert upgrades – Second Avenue, Forestville
First Avenue, Forestville
Regent Street, Millswood
Orphanage Park (internal road bridge) concept design
through Orphanage Park yet to be confirmed
Charles Street, Forestville
Ethel Street, Forestville
Northgate Street, Unley Park
Goodwood Road Culvert
Keswick Creek
Le Hunte Street Diversion – All three sections (Program 2025/26 – 2031/32).
Glen Osmond Creek
Fern Avenue, Fullarton Bridge upgrade.
Torrens Avenue, Fullarton Bridge upgrade.
Minor upgrades along Glen Osmond Creek between Braeside Avenue and
Burnham Avenue.
4.
For each project completed so far how much has the risk of flooding in
Unley reduced?
It is not possible to quantify the exact extent of reduction in flood risk,
however, in the proximity of each project and immediately downstream
there is a significant reduction in flood potential. The projects completed
and soon to be completed in the next few years have/will greatly reduce
the risk of flooding along Glen Osmond Creek, Parklands Creek and, to
some extent, Keswick Creek. The minor projects that have been
completed along Brown Hill Creek have had little impact on flood reduction
accept in the local area of the works.
5.
At what point will the risk have been reduced to an acceptable level?
The widely accepted stormwater industry standard for flood protection is 100yr ARI
(Average Recurrence Interval) or 1% AEP (Annual Exceedance Probability). This standard
is what has been assumed in the BHKC SMP. The project is scheduled to be completed
over 20 years and therefore the modelled 100yr ARI flood protection will not occur until
all projects are completed. Within the City of Unley – the Creek widening and bridge
replacement between Victoria Street and Cross Road (Area 2 ‐ Area 4 including
Orphanage Park) and Glen Osmond Creek minor upgrades are the last projects
scheduled and are proposed to be completed in year 20, 2035/36.
