Agenda of Central Floodplain Risk Management Committee

Central Floodplain Risk Management Committee – 11 August 2021

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Membership

Clr Proudfoot (Chairperson)

All Councillors

CEO or nominee

Community representatives:-

Richard Carpenter

David Tarbert

Zachariah Cleary

Peter Foggitt

Janis Natt

Government Agency representatives:-

Local Aboriginal Land Council

NSW State Emergency Services

Department of Planning, Environment and Industry (DPIE)

Other relevant Government Agency representatives

Quorum – Three (3) provided that a minimum of the Chairperson and two community representatives are present.

Purpose:

The principal objective of the Central Floodplain Risk Management Committee is to assist Shoalhaven City Council in the development and implementation of one or more floodplain risk management plans for the central area of the Council. This will need to be in accordance with the NSW Floodplain Development Manual. The central area applies to the following catchments:

· St Georges Basin (includes Sussex inlet);

· Jervis Bay;

· Currambene Creek;

· Moona Moona Creek;

· Currarong Creek;

· Berrara Creek

· Callala Creek; and

· Swan Lake

Role:

1. To assist the Council in the development and implementation of the floodplain management plan for the areas listed under ‘Purpose’ (see above);

2. To assist the Council monitoring and assessing the effectiveness of the management plans during and after its implementation; and

3. To assist the Council providing input into known flood behaviour as part of the flood study.

Minutes of the Central Floodplain Risk Management Committee

Meeting Date: Wednesday, 21 April 2021

Location: Council Chambers, City Administrative Centre, Bridge Road, Nowra

Time: 4.07pm

The following members were present:

Clr Patricia White - Chair

Clr Nina Digiglio – (Remotely)

Mr Zachariah Cleary (Remotely)

Ms Janis Natt

Mr Phil Hansen - Acting Environmental Services Manager – (CEO Nominee)

Others Present:

Mr Mark Stone – Senior Floodplain Engineer

Mr John Murtagh - Department of Planning, Environment and Industry (DPIE) (Remotely)

Rod Whalen – NSW State emergency Services (Remotely)

Mr Julian Skipworth - Water Modelling Solutions (Remotely)

Apologies / Leave of Absence

An apology was received from David Tarbert, Richard Carpenter and Charles Court – Safe Navigation Action Group Inc.

Confirmation of the Minutes

Recommendation

That the Minutes of the Central Floodplain Risk Management Committee held on Wednesday 25 November 2020 be confirmed.

RESOLVED (Janis Natt / Clr White)

That the Minutes of the Central Floodplain Risk Management Committee held on Wednesday 25 November 2020 be confirmed.

CARRIED

Declarations of Interest

Nil.

Presentations

CFM21.1 Floodplain Risk Management Presentation

HPERM Ref: D21/141856

John Murtagh, Department of Planning, Industry and Environment (DPIE) gave a presentation on Floodplain Risk Management in the context of the Shoalhaven, and the role of the Committee.

The presentation is attached to these minutes.

Clr White raised a question whether Burrill Lake would be eligible for flood funding as the most recent flood studies done for Burrill Lake are quite old. Would a new review need to be conducted to deem Burrill Lake eligible for funding? Mr Murtagh advised that any mitigation measures that are included in the Floodplain Risk Management Plan are eligible for a funding contribution from DPIE. He did however address the meeting later on this point where he advised that there was merit in reviewing either the Burrill Lake Flood Study (adopted 2007) or the Floodplain Risk Management Study (adopted 2013).

Clr White advised that many Burrill Lake residents have raised concerns in regard to the increase in their insurance premiums due to the construction of the new Burrill Lake Bridge.

CFM21.2 Draft Currarong Creek Flood Study Presentation

HPERM Ref: D21/141861

Julian Skipworth, Water Modelling Solutions, gave a presentation to the meeting.

There are two methods of flood modelling basics that are used in this Flood Study, the Rainfall model and the Flood or Hydraulic model.

The key findings of the study are:

1. Currarong Road at Currarong Creek inundated in fairly frequent events (20% AEP and upwards) but to shallow depths and generally low velocity

2. Currarong Road begins to become unpassable in a 20% AEP event for small vehicles

3. Unpassable to all vehicles in a 5% AEP event

4. Eastern half of Currarong becomes isolated

5. Walton and Fishery Road may be cut in short duration storms (greater than 20% AEP)

6. Ponding water may develop in the western areas of Currarong starting in the 20% AEP event

7. Hazard will generally remain low for people but may cause above floor level inundation depending on ground conditions

8. Deeper inundation is generally well-confined to waterways rather than properties

9. Risk to property is generally quite low other than some small pockets

10. Main issue is overtopping of Currarong Road which cuts the evacuation route

11. Sea level rise has minimal impact on flood risk in this catchment

12. More critical event seems to be durations of 6-12 hours

Reports

CFM21.3 Draft Currarong Creek Flood Study

HPERM Ref: D21/139378

Council and DPIE have reviewed and provided feedback into the report. SES have not yet had a chance to respond as it coincided with the recent flooding across the State.

During discussion, it was raised that Council has a Policy for riverine flooding but not overland flooding. It was proposed that Council develop an overland flooding policy.

A copy of the presentation is attached to these Minutes.

Recommendation (Item to be determined under delegated authority)

The Committee receive the draft Currarong Creek Flood Study report for information and endorse the commencement of community engagement for the Draft Flood Study.

RESOLVED (Janis Natt / Zachariah Cleary)

That the Committee receive the draft Currarong Creek Flood Study report for information and endorse the commencement of community engagement for the Draft Flood Study.

CARRIED

CFM21.4 Update on the St Georges Basin Floodplain Risk Management Study & Plan

HPERM Ref: D21/141237

Mark Stone provided a verbal update in relation to the St Georges Basin Floodplain Risk Management Study & Plan.

Lower Shoalhaven River and St Georges Basin Floodplain Risk Management Study & Plan (FRMS&P) peer review is underway and expected to be completed soon. The Flood Study will continue and be finalised.

The findings from the draft Flood Study report will be presented to a future Floodplain Risk Management Committee (FRMC) meeting to seek endorsement to undertake community consultation and public exhibition of the Flood Study report. At this time input will also be requested for options to be considered in the FRMS&P.

The DPIE funding term completion date is 20 November 2021.

At the previous FRMC meeting there was discussion resulting in a recommendation to end the investigation at a Flood Study only, but Council is now more confident that a Flood Study and some of the FRMS&P can be completed within the DPIE funding term. The FRMS&P milestones not completed by the funding term will need to be funded with a budget bid (if successful) and / or Council’s Flood Program Budget.

Clr White raised the question that if there is a shortfall of funding after November 2021 is there an option to approach Department of Planning, Industry and Environment for additional funds.

John Murtagh explained that because the scope of the study had expanded from the original funding application (to approximately twice the original application amount), followed by DPIE offering a 60% increase in funding that there would be no scope to obtain additional funding or a time extension. However, there may be scope to apply for future funding in grant round but unsure at this point in time.

He added this note: Currarong Creek Flood Study – Limited hazard in overland flow but could enter houses. Intent is to try to ensure floor level of house is sufficiently high for overland flooding to flow around the house rather than through the house.

St Georges Basin / Sussex Inlet and Broughton Creek are high priority for review.

Recommendation (Item to be determined under delegated authority)

The Committee receive the report for information and endorse the continuation of this flood investigation through to the completion of the Floodplain Risk Management Study & Plan.

RESOLVED (Janis Natt / Zachariah Cleary)

That the Committee:

1. Receive the report for information and endorse the continuation of this flood investigation through to the completion of the Floodplain Risk Management Study & Plan.

2. Receive a report to a future meeting on the current status of the Works Program and the priorities.

CARRIED

GENERAL BUSINESS

CFM21.5 Additional Item - Currarong Creek Study - Verbal Update

Rodney Whalen – NSW State Emergency Services provided an update on the Currarong Creek Flood Study. SES will review the Draft Currarong Creek Flood Study and provide feedback.

Mark Stone advised that this feedback is welcome at any stage prior to the end of the community consultation period.

Note: Phil Hansen, Acting Environmental Services Manager, advised the meeting that he will be completing his acting role and Michael Roberts will be commencing in May as Kelie Clarke’s replacement.

Clr White thanked Phil for an excellent job especially over the last few months with the flood events.

Janis Natt thanked Phil for engaging the community during his time in the role.

There being no further business, the meeting concluded, the time being 5.50pm.

Clr Patricia White

CHAIRPERSON

Central Floodplain Risk Management Committee – 11 August 2021

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CFM21.7 Changes to DPIE Floodplain Risk Management Representative for the Shoalhaven LGA

HPERM Ref: D21/276757

Department: Environmental Services

Approver: Phil Costello, Director - City Development

Reason for Report

To provide Council and the Central Floodplain Risk Management Committee (FRMC) with an update on changes to NSW Department of Planning, Industry and Environment (DPIE) Floodplain Risk Management representative for the Shoalhaven LGA.

Recommendation (Item to be determined under delegated authority)

The Committee receive the report for information.

Options

1. The Committee receive the report for information.

Implications: Nil.

2. The Committee could choose to provide an alternative recommendation for consideration by Council.

Implications: Unknown.

NSW Government Floodplain Risk Management Program

DPIE administers the program supporting Councils with:

§ Policy advice, including a manual and series of technical guides as well as access to grant funding (available via the DPIE website).

§ Technical support from Regional Representatives with:

o Grant Applications.

o Technical Briefs.

o Review of Progress, Draft and Final Reports.

o Works Investigation, Design, Construction.

o Floodplain Risk Management Committee Operation.

o Councillor briefings when requested.

The DPIE Floodplain Risk Management representative for the Shoalhaven LGA is therefore an incredibly valuable resource to assist Council to deliver its responsibilities under the Floodplain Risk Management Program.

Changes to DPIE Floodplain Risk Management Representative

John Murtagh from DPIE has been Council’s floodplain risk management representative for many years. John has extensive knowledge of flooding issues within the Shoalhaven Region and has provided expert technical support for the majority of previous flood investigations undertaken by Council. His efforts and commitment to the Shoalhaven Region has been invaluable for Council to understand, and where possible, manage the flood risk to the Shoalhaven community.

John Murtagh has recently taken extended leave from DPIE and is therefore unavailable to attend this FRMC meeting. John asked that the following message be conveyed to all Councillors and the members of the FRMC.

“I would appreciate it if my heartfelt thanks for all the great collaboration I have received from the SCC Councillors, staff & communities could be conveyed to the meeting on my behalf”.

It is noted that Nathan Promfret will be taking over as the primary DPIE Regional Floodplain Risk Management representative. Nathan has extensive technical knowledge in floodplain risk management, in addition to knowledge of the Shoalhaven Region and Council are looking forward to working with Nathan and other DPIE staff on current and future flood investigations.

Policy Implications

None.

Financial Implications

None.

Central Floodplain Risk Management Committee – 11 August 2021

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CFM21.8 Update on Councils Flood Program

HPERM Ref: D21/276762

Department: Environmental Services

Approver: Phil Costello, Director - City Development

Reason for Report

To provide Council and the Central Floodplain Risk Management Committee (FRMC) with an update on Council’s Flood Program.

Recommendation (Item to be determined under delegated authority)

The Committee receive the report for information.

Options

1. The Committee receive the report for information.

Implications: Nil.

2. The Committee could choose to provide an alternative recommendation for consideration by Council.

Implications: Unknown.

Background

Council has a forward Flood Program which identifies and prioritises new and updated flood investigations for the Shoalhaven LGA. These flood investigations cover all phases of the floodplain risk management process from Flood Studies, Floodplain Risk Management Studies (FRMS), Floodplain Risk Management Plans (FRMP) and implementation of mitigation measures identified from these investigations.

Council can request grant funding from the Department of Planning Industry and Environment (DPIE) which administer the NSW Government Floodplain Risk Management Program. Flood investigations that are successful in obtaining grant funding are 2/3 funded by DPIE and 1/3 funded by Council.

A resolution of the Central FRMC meeting on 21 April 2021 was that Council would provide an update on Council’s Flood Program and priorities at the next scheduled FRMC meeting. As such, this report summarises Councils adopted flood investigations, investigations which are currently underway, outstanding investigations, investigations that require an update and preliminary priorities for the completion of these flood investigations.

It is noted that flood investigations are typically recommended to be updated every ten years or following a significant flood event and/or changes within the catchment.

The majority of Council’s flood investigations were developed prior to the update to the Australian Rainfall and Runoff guidelines (ARR2019), which provide Australian industry guidelines for flood estimation. The ongoing Millards Creek Flood Study, Currarong Creek Flood Study, Lower Shoalhaven River FRMS&P and St Georges Basin FRMS&P are being developed in accordance with the ARR2019 guidelines. Council’s existing flood investigations will need to be progressively updated in accordance with the ARR2019 guidelines.

Summary of Flood Program Priorities

A summary of Council’s Flood Program and preliminary priorities are provided below. Flood investigations have typically been identified as either a High, Medium or Low priority. It is noted that the ranking of flood investigations within each of the priorities has not been identified at this stage and these can change with time as a result of a number of factors, such as changes within each catchment, flood events and community expectations.

Council would welcome any feedback from the FRMC on the proposed forward Flood Program and associated priorities.

High Priority

§ Update to Lower Shoalhaven Flood Study and FRMS&P – in progress.

§ Update to St Georges Basin Flood Study and FRMS&P – in progress.

§ Update to Broughton Creek Flood Study and FRMS&P – Council has applied for DPIE grant funding and included Councils 1/3 contribution in the Delivery Program Operational Program (DPOP).

Medium Priority

§ Millards Creek FRMS&P. Ideally including Racecourse Creek, Mollymook Creek and Narrawallee Creek – Council intends to apply for grant funding for this investigation in the next round of DPIE grant funding.

§ Willinga Lake Flood Study and FRMS&P. Ideally including all creeks south to Pretty Beach – Council intends to apply for grant funding for this investigation in the next round of DPIE grant funding.

§ Update to Nowra and Browns Creek FRMS&P. Ideally including the entire Nowra urban areas.

Low Priority

§ Callala Creek Flood Study, Swan Lake Flood Study and Clyde River Flood Study. Council currently has limited flood information in these catchments. Callala Creek could be included with an update to the Currambene and Moona Moona Creek FRMS&P.

§ Currarong Creek FRMS&P.

§ Update to the Currambene and Moona Moona Creek FRMS&P, Kangaroo Valley FRMS&P, Bomaderry Creek FRMS&P, Burrill Lake FRMS&P, Lake Tabourie FRMS&P and Lake Conjola FRMS&P.

Detailed Summary of Flood Program

The following table provides a summary of Council’s adopted flood investigations, investigations which are currently underway, outstanding investigations, investigations that require an update and preliminary priorities for the completion of these flood investigations. A number of these flood investigations are recommended to be undertaken following the completion of major transport projects that are either underway or in the planning stage.

Flood Study / FRMS&P	Comments	Priority
*Northern FRMC*
Broughton Creek FRMS&P (2011). Broughton Creek Flood Study (2012).	Significant changes in catchment such as the TfNSW Berry to Bomaderry Bypass. Update to Flood Study (including ARR2019) and FRMS&P is required. Council has applied for grant funding from DPIE.	High
Bomaderry Creek Floodplain Risk Management Plan (2016). Bomaderry Creek Floodplain Risk Management Study (2016). Bomaderry Creek Flood Study (2010).	Update to FRMS&P not currently required. Flood Study is 10 years old and requires updating to ARR2019. Flood Study and FRMS&P should be updated following completion of the Nowra Bridge Duplication and Far North Collector Road projects. At this stage, the extent of significant urban expansion in this catchment will be better understood which will allow the ultimate development scenarios to be included.	Low
Nowra and Browns Creek Floodplain Risk Management Plan (2016). Nowra and Browns Creek Floodplain Risk Management Study (2016). Nowra and Browns Creek Flood Study (2005).	Flood Study is over 15 years old and requires updating to ARR2019. This would include direct rainfall modelling for the Nowra urban area and urban growth areas (commercial and residential) beyond the current study area. The Flood Study and FRMS&P should be updated in the next five years.	Medium
Kangaroo Valley Floodplain Risk Management Plan (2016). Kangaroo Valley Floodplain Risk Management Study (2016). Kangaroo Valley Flood Study (2009).	Flood Study is over 10 years old and requires updating to ARR2019. The review of the Shoalhaven River catchment provides an opportunity to update this Flood Study and FRMS&P to be consistent with the outcomes of the Lower Shoalhaven River FRMS&P. The Flood Study and FRMS&P should be updated in the next five years.	Low
Lower Shoalhaven River Floodplain Management Study & Plan – Climate Change Assessment (2011). Lower Shoalhaven River Floodplain Risk Management Plan (2008). Lower Shoalhaven River Floodplain Risk Management Study (2008). Lower Shoalhaven River Flood Study (1990). Riverview Road Floodplain Risk Management Plan (2002). Riverview Road Floodplain Risk Management Study (2002). Terara Floodplain Risk Management Plan (2002). Terara Floodplain Risk Management Study (2002).	Update to Flood Study and FRMS&P currently underway.	High
Lake Wollumboola Flood Study (2015).	Update to Flood Study not currently required. FRMS&P unlikely to be required.	Low
*Central FRMC*
Currarong Creek Flood Study.	Flood Study underway and to be completed in 2021. Consider applying for grant funding to complete FRMS&P following the completion of the CMP. The Community Consultation for the Flood Study has highlighted a number of issues to warrant the completion of a FRMS&P.	Low
Callala Creek Flood Study.	No contemporary Flood Study completed. Limited flood information available from a 1994 study. Callala Beach and Myola could be isolated as a result of Callala Creek flooding. This could be considered as part of the Currambene and Moona Moona Creek review. Consider applying for grant funding to complete Flood Study.	Low
Currambene and Moona Moona Creek FRMS&P (2016). Currambene Creek and Moona Moona Creek Flood Study (2006).	Flood Study is 15 years old and requires updating to ARR2019. Consider including Callala Creek in this FRMS&P review. The Flood Study and FRMS&P should be updated in the next five years.	Low
St Georges Basin Floodplain Risk Management Study & Plan – Climate Change Assessment (2013). St Georges Basin Floodplain Risk Management Plan (2006). St Georges Basin Floodplain Risk Management Study (2006). St Georges Basin Flood Study (2001).	Update to Flood Study and FRMS&P currently underway.	High
Swan Lake	No Flood Study completed. Some low-lying areas in Cudmirrah. Consider applying for grant funding to complete Flood Study.	Low
*Southern FRMC*
Lake Conjola FRMS&P (2013). Lake Conjola Flood Study (2007).	Update to Flood Study and FRMS&P not currently required. Consider update Flood Study and FRMS&P following the completion of the Lake Conjola CMP if needed.	Low
Narrawallee Creek.	No Flood Study completed. Consider applying for grant funding to complete Flood Study. This could be included in the scope of the Millards Creek FRMS&P.	Low
Millards Creek Flood Study.	Flood Study underway and to be completed in 2021. Council to apply for grant funding to complete FRMS&P. The Community Consultation for the Flood Study has highlighted a number of issues to warrant the completion of a FRMS&P. Ideally the scope would be expanded to include Racecourse Creek (isolation considerations for the SES) catchment to cover all of Ulladulla and also include Mollymook Creek and Narrawallee Creek.	Medium
Burrill Lake FRMS&P (2013). Burrill Lake Flood Study (2007).	Update to Flood Study required to include the new Burrill Lake bridge and ARR2019. The FRMS&P is also eight years old so should be updated. However, this should await the outcomes of the final Milton to Ulladulla Bypass which is currently being considered by TfNSW. The Flood Study and FRMS&P should be updated in the next five years.	Low
Lake Tabourie Floodplain Risk Management Plan (2016). Lake Tabourie Floodplain Risk Management Study (2016). Lake Tabourie Flood Study (2010).	Flood Study is over 10 years old and requires updating to ARR2019. However, this should await the outcomes of the proposed highway upgrade being considered by TfNSW at this location. The Flood Study and FRMS&P should be updated in the next five years.	Low
Willinga Lake.	No Flood Study completed. There are isolation risks for the Bawley Point and Kioloa communities associated with Willinga Lake. Flood Study to consider all relevant waterways that may impact on communities from the Princes Highway to Pretty Beach. Council to apply for grant funding to complete Flood Study and FRMS&P.	Medium
Clyde River.	No Flood Study completed. There are isolation issues for vulnerable communities which emerged following recent floods and bushfires. Emergency response concerns. Consider applying for grant funding to complete Flood Study in partnership with Eurobodalla Shire Council.	Low

CFM21.9 Final Currarong Creek Flood Study

HPERM Ref: D21/276760

Department: Environmental Services

Approver: Phil Costello, Director - City Development

Reason for Report

To provide the Central Floodplain Risk Management Committee (FRMC) with an update on the Currarong Creek Flood Study and seek endorsement from the FRMC for the Final Currarong Creek Flood Study report to be adopted by Council.

Recommendation (Item to be determined under delegated authority)

The Committee receive the Final Currarong Creek Flood Study report for information and endorse the adoption of the Final Flood Study report by Council.

Options

1. The Committee receive the Final Currarong Creek Flood Study report for information and endorse the adoption of the Final Flood Study report by Council.

Implications: Nil.

2. The Committee could choose to provide an alternative recommendation for consideration by Council.

Implications: This option could delay the adoption of the Final Flood Study report, result in additional project costs and / or prevent the completion of a Flood Study within the project timeframe.

Background

The Currarong Creek catchment and associated tributaries are located in Currarong, and discharge to the Tasman Sea.

The objective of this study is to improve understanding of flood behaviour and impacts, and better inform management of flood risk in the study area in consideration of the available information. The study will also provide a sound technical basis for any further studies if this is found to be required. The scope of this flood study includes investigating both riverine and overland flooding within the Currarong Creek catchment.

The need for a Flood Study for the Currarong Creek catchment was identified as part of Council’s floodplain programme. The study outputs will inform decision making for investing in the floodplain, managing flood risk through prevention, preparedness, response and recovery activities, and informing and educating the community on flood risk and response to floods.

Current Status of the Project

The Draft Currarong Creek Flood Study report was presented to the Central FRMC on 21 April 2021. The FRMC endorsed the commencement of the public exhibition and community consultation of the Draft Currarong Creek Flood Study report.

The public exhibition and community consultation was undertaken from 3 May to 28 May 2021.

The Currarong Creek Flood Study report has been updated as required based on the outcomes of the public exhibition and community consultation phase.

The Final Currarong Creek Flood Study report has been completed. Council is seeking endorsement from the FRMC for the Final Currarong Creek Flood Study report to be adopted by Council. A link to the final report was provided with the FRMC meeting agenda.

The Final Currarong Creek Flood Study report will be reported to Council for adoption.

At the previous FRMC meeting, Council advised that some amendments to Development Control Plan Chapter G9: Development of Flood Prone Land are proposed, along with the development of an overland flooding policy as required. These documents would also be reported to Council.

The outcomes of the public exhibition and community consultation phase identified the need to progress the Currarong Creek Flood Study through to a Floodplain Risk Management Study and Plan (FRMS&P). At the appropriate time Council will apply for grant funding from the Department of Planning, Industry and Environment (DPIE) to complete a FRMS&P for the Currarong Creek catchment.

Community Engagement

The first round of community consultation was undertaken between December 2018 and January 2019. A project website was published by Council’s Get Involved website page to inform the community about the Flood Study. This page was designed to get feedback from community about their flooding experience within the catchment.

The public exhibition and community consultation was undertaken from 3 May to 28 May 2021.

The following forms of community engagement were undertaken during the public exhibition and community consultation phase:

§ Media release to inform the community of the community engagement period.

§ Mail out to all property owners and residents within the study area of the Flood Study.

§ An online questionnaire available through the projects Get Involved website to seek feedback from the community.

§ Community drop in session attended by Water Modelling Solutions, Council’s Flood Engineers, Floodplain Risk Management representative from DPIE and members from the NSW State Emergency Services (SES). This drop in session was held at the Currarong Progress Hall on 12 May 2021.

During the public exhibition period, a survey was made available via the Currarong Creek Flood Study Get Involved web page. In summary, there were 119 visits to the Get Involved web page during that period, with 5 surveys completed and 3 email submissions received. The interaction with the page also included 10 downloads of either the study report, fact sheet or mapping.

Key feedback from the survey included:

§ Concerns regarding siltation of the creek and a notable increase in the growth of the mangroves on the western / northern side of the creek. Concerned that “reduced water outflow through the creek” is increasing the potential for flooding.

§ Concern that the footbridge and road bridge create a choke area for flood waters, and that sand dunes at the northern side of the creek opening further narrow the creek.

§ Recommended construction to widen the creek and improve the water flow at the road bridge is required, combined with periodic / annual dredging of the creek.

§ Request that maintenance and budget should be allocated to ensure “the creek is dredged as required and that stormwater channels are freed up of vegetation and debris to allow free flow of water from north and east Currarong that naturally flows into the creek”.

§ Concern that “the health of the waterway has been deteriorating since the 1950's. Urgent action is required to dredge the creek now, until a longer-term solution can be implemented”.

§ Request that “SCC needs to clean all drains to ensure that flood waters have an escape route to the sea. This needs to be done to all drains in Currarong, particularly those in Walton Way”.

§ The key area of concern with regard to flooding is the location in which Plutus Creek crosses Currarong Road. This is a known issue that has been investigated via a separate Flood Investigation and the outcomes of this flood investigation will result in larger culverts installed at Plutus Creek which will significantly increase the level of service of Currarong Road to flood inundation.

The above comments did not require any changes to the Flood Study report or technical analysis. Comments received will, however, be considered during the development of a Floodplain Risk Management Study and Plan in the future.

The community consultation phase identified concerns about the overall health of Currarong Creek. It is considered that these concerns would be best addressed through the Coastal Management Programs (CMPs), which will set a long-term strategy for the coordinated management for Shoalhaven’s coastline and estuaries. Feedback associated with the overall health of Currarong Creek has been provided to Council’s Coastal Coordinator and the members of the community that raised these concerns have been encouraged to participate in the development of the CMPs by attending community sessions and subscribing to Council’s Get Involved web pages.

It is noted that Council provided an individual response to all members of the community that completed the survey.

It is also noted that Council’s Flood Engineers received numerous enquiries from members of the community during the public exhibition and community consultation period. A lot of these enquiries were from members of the community that were unable to access the electronic community consultation material or attend the drop in session for personal reasons. Council’s Flood Engineers were able to assist all of these community members with regard to their enquiries.

No feedback was received from the NSW SES for the Draft Currarong Creek Flood Study report.

Financial Implications

The Currarong Creek Flood Study is 2/3 funded by DPIE and 1/3 funded by Council. There have been no increases in project cost beyond the original approved funding.

Assuming the FRMC endorse the adoption of the Final Currarong Creek Flood Study report by Council, the project will be completed within the DPIE grant funding term.

Any potential project delays could however prevent the project being adopted by Council prior to the end of the DPIE milestone funding term and this could result in increased project costs.

Policy Implications

Council does not currently have a policy with regard to flood specific development controls that apply to locations mapped with overland flooding.

The inclusion of overland flooding in the Currarong Creek Flood Study provides an opportunity for Council to develop a policy on overland flooding and associated minor amendments to DCP Chapter G9: Development on Flood Prone Land, to provide appropriate flood specific development controls for new and redeveloped buildings located in areas that have been identified as comprising overland flooding.

These documents will be reported to Council following the upcoming Local Government elections following their completion.

CFM21.10 Update on St Georges Basin FRMS&P

HPERM Ref: D21/276761

Department: Environmental Services

Approver: Phil Costello, Director - City Development

Reason for Report

To provide Council and the Central Floodplain Risk Management Committee (FRMC) with an update on the review of the Floodplain Risk Management Study & Plan (FRMS&P) for the St Georges Basin catchment.

Recommendation (Item to be determined under delegated authority)

The Committee receive the report for information.

Options

1. The Committee receive the report for information.

Implications: Nil.

2. The Committee could choose to provide an alternative recommendation for consideration by Council.

Implications: This option could delay the progress of the project, result in additional project costs and/or prevent the completion of a Flood Study and FRMS&P within the project timeframe.

Background

The study area comprises St Georges Basin itself, the Estuary area, Sussex Inlet and upstream residential areas along the tributary creeks. The entire catchment covers an area of approximately 358 square kilometres with approximately 10% of the catchment area covered by the Basin itself. The catchment area of the Basin contains a number of creeks including Pats Creek, Home Creek, Wandandian Creek, Tomerong / Cockrow Creek, Cow Creek, Tullarwalla Creek and Worrowing Creek. The Basin connects to the ocean through the Sussex Inlet Channel and there are no recorded periods of closure of the Basin’s entrance.

The previous Floodplain Risk Management Study and Plan (FRMS&P) for St Georges Basin was completed in 2013. A review was recommended as per the NSW Floodplain Development Manual. It is noted that the Australian Rainfall and Runoff (ARR) Guidelines were updated in 2019 and this resulted in a number of changes to input parameters for design event flood modelling, such as the Bureau of Meteorology (BoM) design rainfall depths and ARR rainfall losses and design temporal patterns.

The study outputs will inform decision making for investing in the floodplain, managing flood risk through prevention, preparedness, response and recovery activities, and informing and educating the community on flood risk and response to floods.

Funding was approved by DPIE for this study in October 2017 and Cardno were engaged to prepare the St Georges Basin FRMS&P in June 2018.

Current Status of the Project

The data collection, model development and calibration phases of the investigation have been completed. The hydrological and hydraulic models have been calibrated against historic flood events and were found to provide a reasonable overall calibration.

An external peer review has been completed by Mark Babister from WMAwater.

The consultant is currently undertaking all flood modelling and the associated preparation of flood mapping. Council is expecting to receive a draft St Georges Basin Flood Study report by mid-September 2021.

Following agency review, the draft St Georges Basin Flood Study report will be presented to the Central FRMC for comment and to seek the committee’s endorsement to commence public exhibition and community consultation. It is envisioned that the public exhibition and community consultation will include both the outcomes from the draft St Georges Basin Flood Study report, as well as, seeking input from the community on potential mitigation measures to be considered as part of the FRMS&P phase of the project. The next Central FRMC meeting is therefore expected to be held following the upcoming Local Government elections.

Accordingly, it will be crucial to re-establish membership of the Central FRMC following the upcoming Local Government elections as quickly as possible to prevent any further delays to the completion of the St Georges Basin Flood Study and FRMS&P.

Community Engagement

The first round of community consultation was undertaken between November 2018 and February 2019. A project website was published by Council to inform the community about this project.

Following the completion of the draft St Georges Basin Flood Study, the outcomes will be presented at a FRMC meeting to seek endorsement to commence community consultation and public exhibition.

Financial Implications

The St Georges Basin FRMS&P is 2/3 funded by DPIE and 1/3 funded by Council. This funding has been approved under the NSW State Government ‘Floodplain Management Program’ on a 2:1 basis. Council’s matching 1/3 contribution comes from the existing general Floodplain Management Program budget. There have been no increases in project cost beyond the original approved funding other than the external peer review.

The grant funding milestones associated with the completion of the Flood Study phase will be completed within the current DPIE funding term.

The aspects of the FRMS&P that are not completed by the project completion date are expected to be able to be funded through a capital budget bid and Council’s flood program budget.