agenda of floodplain management committee - 6 august … · the report he was disappointed that the...

Floodplain Management Committee | 06 August 2015 1

AGENDA

FLOODPLAIN MANAGEMENT COMMITTEE TO BE HELD IN COUNCIL CHAMBERS ON THURSDAY, 6 AUGUST 2015 AT 1:00 PM

1 Apologies

2 Confirmation of Minutes

3 Business Arising

4 Declarations of Interest

5 Items of Business

CL01 p32 Presentation & Report - Darren Lyons Griffith Main Drain J & Mirrool Creek Floodplain Risk Management

Study & Plan - Response to Submissions received during public exhibition of the report

6 p58 Outstanding Action Report

7 General Business (a) FMA Quarterly Meeting – 20 August 2015, BOM Building, Sydney

8 Next Meeting

DISTRIBUTION LIST

Councillor Bill Lancaster (Chair), Councillor Simon Croce, Councillor Paul Rossetto, Leon Thorpe (Councillor - Alternate), Dino Zappacosta (Councillor - Alternate), Peter Budd (Community Rep), Joseph Dal Broi (Community Rep), Michael Fisher (Community Rep), Louie Forner (Community Rep), Dave Gilbert (Stakeholder), Paul Giovinazzo (Community), Sally Jones (Community Rep), Richard (Steve) Mortlock (Stakeholder), Peter Nankivell (Stakeholder), Peter Ryrie (Community Rep) General Manager, Brett Stonestreet; Director Utilities, Graham Gordon; Director Sustainable Development, Neil Southorn; Engineering Design Approvals Manager, Joe Rizzo; Senior Infrastructure Planning Coordinator, Durgananda Chaudhary; Landuse Planning and Compliance Coordinator, Kelly McNicol; Minute Secretary, Wendy Krzus

Quorum = 7

If you are unable to attend this meeting please notify the Minute Secretary prior to commencement of the meeting by email or by telephoning Council on 69628100.


MINUTES

FLOODPLAIN MANAGEMENT COMMITTEE HELD IN COUNCIL CHAMBERS ON

THURSDAY, 30 APRIL 2015 COMMENCING AT 1.00 PM

PRESENT

Councillor Bill Lancaster (Chair), Councillor Paul Rossetto, Councillor Simon Croce, Councillor Dino Zappacosta (Alternate), Councillor Leon Thorpe (Alternate), Louie Forner (Community), Peter Budd (Community), Sally Jones (Community), Peter Nankivell (OEH), Paul Giovinazzo (Community) & Dave Gilbert (MI)

Quorum = 7

STAFF

Director Sustainable Development, Neil Southorn; Director Utilities, Graham Gordon; Senior Infrastructure Planning Coordinator, Durgananda Chaudhary; Engineering Design & Approvals Manager, Joe Rizzo & Minute Secretary, Wendy Krzus.

CONSULTANT

Darren Lyons BMT WBM

1 APOLOGIES

RECOMMENDED on the motion of Councillor Paul Rossetto and Peter Budd that apologies be received from Joseph Dal Broi (Community), Peter Ryrie (Community), Steve Mortlock (SES) and General Manager, Brett Stonestreet

2 CONFIRMATION OF MINUTES

RECOMMENDED on the motion of Councillor Paul Rossetto and Peter Budd that the minutes of the previous meeting held on 4 December 2014 having first been circulated amongst members, be confirmed with the following amendments:

Minutes - Page 6

Paragraph 6 – the year 1991 be amended to 1999.

Sentence to read:

“Mr Gilbert stated that MI was note in existence at that time and that he thought it was the NSW Government who were the entity who changed those arrangements and that MI had only been privatised since 1999.”


Minutes – Page 7 Paragraph 3, second sentence. Insert the following text “abandoned flood structure at the”, after the words “acknowledged their responsibility for the operation of the……..” Delete the words “and in particular the flood gates”. Sentence to read: “Mr Gilbert acknowledged that Mr Borrows made reference to correspondence MI received from Council in 2013 where Council identified and acknowledged their responsibility for the operation of the abandoned flood structure at the EMR.” Minutes – Page 7 Point 2 – Mr Burrows to be corrected to read “Mr Borrows” Sentence to read: “Mr Budd made reference to the second last paragraph in Mr Borrow’s letter ……” Minutes – Page 8 Attachments (a) Correct spelling. Mr Burrows to be corrected to read “Mr Borrows”. Sentence to read: “(a) Letter to Chief Executive Officer MI, Peter Borrows from Director Utilities GCC, Graham Gordon re invitation to Mr Borrows to attend the next Floodplain Management Committee Meeting, dated 5 November 2014.” 3 BUSINESS ARISING Councillor Rossetto expressed his concern regarding the length of time between meetings, with the last meeting having been held on 4 December 2014. The Chair stated that there were reasons for the time delay between meetings and that staff were very conscious of this.

4 DECLARATIONS OF INTEREST Less Than Significant Non-Pecuniary Interests Members making a less than significant non-pecuniary interest declaration may stay in the meeting and participate in the debate and vote on the matter. Peter Budd - Agenda in general Reason - Mr Budd has clients that have properties in a floodway south of Mackay Avenue. The agenda items are general in nature and not property specific. Should discussion become more specific, there may be a conflict and a further declaration may be made at that time. Councillor Paul Rossetto – Clause 02 – Presentations and Reports – Raise NBC Bank Reason – If the NBC is enlarged to raise bank NBC irrigators may benefit by increased D/E entitlements. Councillor Rossetto has an orchard on NBC. Section 448(c) may apply. Councillor Paul Rossetto – Clause 02 – Presentations and Report – Flood Report – MI Stakeholder. Reason – Councillor Rossetto is a minority shareholder of MI. No Significant influence on MI.


Councillor Croce left the meeting, the time being 1.12 pm. Councillor Croce returned to the meeting, the time being 1.13 pm. 5 ITEMS OF BUSINESS CL01 MINUTES OF TECHNICAL SUB-COMMITTEE MEETING – 15 APRIL 2015 Mr Gordon stated that the minutes of the Sub-Committee have been distributed to all members of the Sub-Committee and that comments have been received back from OEH and MI which are incorporated in the minutes which are attached to today’s agenda. Mr Budd enquired if the document received this week, being the Griffith Main Drain J and Mirrool Creek Floodplain Risk Management Study and Plan dated April 2015 had been amended or massaged based on the technical teleconference held on 15 April 2015.

My Lyons advised that the document had been amended to include the issues raised by the Technical Sub Committee.

Mr Gordon apologised for the lateness of the report and advised that the intention was to have the document well before this meeting for the Committee to comprehensively review. Mr Gordon stated that the minutes of the Technical Review Sub Committee highlights a lot of the concerns that the Technical Committee had and that Mr Lyons will address these issues in his presentation and how they are reflected in the document.

Mr Budd enquired about the flood immunity level for Yenda and if the freeboard of 2% and 5% was still current in the document.

Mr Lyons advised that the content of today’s presentation would involve and discuss the freeboard.

Councillor Rossetto enquired if there was any information from the Technical Committee that had been excluded from the report as be had noted that both the minutes and the report appeared to be similar.

Mr Lyons advised that the majority of changes involved the addition of information rather than exclusions or modifications.

Councillor Rossetto stated that when he was reading the Technical Committee Minutes and the report he was disappointed that the Lawson Syphon option appears towards the end of the meeting, appearing as though it is an add on and not a preferred option.

Mr Lyons advised that the updated report has the Lawson Syphon structure as a standalone option and is certainly clear in the revised report that there is no preferred option and that it is one of the potential feasible options equally feasible as any other type of structure arrangement and that it has not been excluded or has a lower propriety to other EMR based options that are presented. CL02 PRESENTATIONS AND REPORTS Griffith Main Drain J and Mirrool Creek Floodplain Risk Management Study and Plan – Draft Final Report for Public Exhibition – Darren Lyons BMT WBM

Mr Lyons acknowledged the delay in the delivery of the report and apologised for the less than ideal time for the Committee to review the report prior to today’s meeting.


Mr Lyons advised that the content of today’s session would give the Committee a real insight into the outcomes and recommendations of the report.

My Lyons presented a PowerPoint presentation, with the following information being noted:

Update

• Review of Draft Report for Public Exhibition • Focus on Recommended Floodplain Risk Management Plan measures/mitigation

options • Review of Griffith FRMS&P (2011) • Local solutions for:

o Yoogali o Yenda o Hanwood

Previous Griffith FRMS&P Recommendations

• New mapping produced in Council adopted updated flood study (BMT WBM 2014) • Formalisation in the FRMP

• PL10 and PL11 - Revised understanding of Main Drain ‘J’ catchment flood behaviour makes the real-time data at these locations of little benefit for flood warning purposes


• ST1 – Upgrade of Main Drain ‘J’ between Bilbul and Yoogali (Option S6) – largely updated with reference to revised flood study results and revised Yoogali flood protection options

• ST2 – Channel widening of Main Drain ‘J’ in vicinity of Yoogali and Hanwood (Option S7) – not required, additional capacity proposed through bank raising.

• ST5 – floodways confined to main channels in updated flood risk mapping • ST6 – flood study revision superseded all previous modelling and associated mapping

Yoogali Options

• Spill points evident in topography • DC 605 J flows controlled by Main Canal and siphons • Solution to retain more flow in-bank & discharge to MD J • Proposed embankment / bank height raising – DC605J / DC 621J / MD J • Culvert upgrades – Yenda Road and Bosanquet Road • Costs ~$500K – the majority of this in the culverts • Low B/C ratio because flood damages occur at 1% AEP events and above • Higher social costs / scheme benefits for works justification

Yenda Options

• Focus on EMR upgrade options • Various configurations available – but broadly can be described as:

• Gate type structure (Main Canal spill through of Mirrool Ck flows) • Siphon type structure (Main Canal flows siphoned under Mirrool Ck) • Fundamentally, any structural configuration is to increase the transfer capacity of

Mirrool Creek flows across the Main Canal • Objective to remove/reduce the redistribution of flow from the Mirrool Ck

floodplain to Yenda and North Yenda (MD J catchment)


• Design based on Stage-Discharge relationship at the EMR with a critical / threshold water level

NBC Embankment

• Critical level along NBC 134.3m AHD • At existing flood escape 134.8m AHD • DWR (1991) options report based structure capacity on 134.9m AHD • NBC embankment works proposed to raise critical spill level to 134.8m AHD • Structures designed for: • 1% AEP capacity at 134.3m AHD (provides for 0.5m freeboard) • 0.5% AEP capacity at 134.5m AHD (provides for 0.3m freeboard) • NBC works integral to design and performance of EMR upgrade options

Reinstate Existing Flood Gates

• Increase existing 5% AEP capacity to 2% AEP capacity • With NBC works that would provide a flood protection standard of 2% AEP + 0.5m

freeboard • Recognition that this option may be simple or straight forward, subject to:

• Full condition assessment • Structural/geotechnical integrity • Gate configurations / operations

• If cost is high to reinstate, preferred option to move to new structure • Interim measure - Ultimate solution to provide a full upgrade

Upgrade of EMR Flood Escape

• Design requirements: • ~120m3/s @ WL of 134.3m AHD (1% AEP +0.5m freeboard) • ~150m3/s @ WL of 134.5m AHD (0.5% AEP +0.3m freeboard)

• Provides for equivalent of March 2012 flows plus the freeboard • At this stage, configuration detail is conceptual – there will be numerous design

solutions to provide for above hydraulic performance requirement • Designs expected to be heavily influenced by MI requirements in integrating with

existing infrastructure and operations • Critical requirement is the nominal design capacity

Upgrade of EMR Flood Escape

• Existing siphons retained for low flows • U/S & D/S structures

• ~9bay 2.4m x 1.8m • U/S and D/S channel works to provide transitions • Bed and bank stabilisation works • Gate functions for MI operations


Lawson Siphon Type Structure

• Same design requirements: • ~120m3/s @ WL of 134.3m AHD (1% AEP +0.5m freeboard) • ~150m3/s @ WL of 134.5m AHD (0.5% AEP +0.3m freeboard)

• Approximate width of 70-100m depending on Mirool Ck floodway section channel and floodplain • Aim to maximise length – economies of scale with increasing width, other design

constraints.

Siphon General Arrangement

• Constraints: • D/S floodway width • Bend in Main Canal • Hydraulic performance for MI operations • Integrating with main regulator and NBC offtake • Environmental impact assessment

EMR Upgrade Impacts

• Effectively the same for any configuration • Increase in flow to Mirrool Creek floodplain to compensate for reduced flow to Yenda • General increases in WL typically 0.1-0.2m

Increase in inundated area in Mirrool Ck floodplain (~20%) Lawson Siphons Impacts • Effectively the same for any configuration • Increase in flow to Mirrool Creek floodplain to compensate for reduced flow to Yenda • General increases in WL typically 0.1-0.2m • Increase in inundated area in Mirrool Ck floodplain (~20%) • Acceptability?

• Restoring a more natural floodplain flow distribution • Existing floodways based on nominal 1% AEP conditions • Largely agricultural area impacted • Trade off is 600+ Yenda properties • Impacts only materialise for 1% AEP events and above • Limited impact on D/S road immunity

Proposed EMR Works Package

• Reinstatement of existing structure: • Condition assessment (incl. structural and geotech) ~$200K • Hold point for above to consider feasibility • Preliminary design and costing, approvals • Detailed design and construct

• NBC bank raising works • Survey and bulk earthworks ~$500K

• EMR Upgrade • Feasibility / preferred option identification ~$100K • Preliminary Design / EIS / Approvals ~$500K • Detailed Design and construct ~$10M+

• Recommended as a package – staged implementation and funding

Hanwood Option


• Largely backwater inundation from MD J • Local drainage and bunding works proposed • Potential pumping enhancements • Cost ~$250K • MD J capacity works also provide benefit to some Hanwood locations

Main Drain J Capacity Works

• General profile/section has some additional capacity • Localised spilling at low points along the banks

• Natural topographical variations • Previous bank scraping

• Not extensive raising works required - scale of bank increases ~0.3m • Benefits to lower floodplain – once flows are out of bank there is limited

opportunity to re-enter the Drain • Continue capacity works D/S Walla Ave

Other Measures

• Planning and Development Controls • 1% AEP Flood Classifications • Floodway definition / Flood Planning Area

• Emergency Response • Updates to Local Flood Plan • New flood intelligence from March 2012 event and Flood Study results • Changes to evacuation procedures and property protection

• Flood Warning (some opportunity) • With structural works MD J system largely 0.5% AEP capacity - protection for

Yoogali and other areas March 2012 magnitude • Similarly Yenda works ultimately provide protection, warning system some

interim benefit • Benefits to MI operations and D/S properties - flows to Barren Box

Next Steps

• Completion of the study and ultimately adoption of the recommended FRM Plan represents a major step in ongoing floodplain risk management for the study area with a number of positive outcomes including:

• that a number of options have been identified and recommended that would alleviate the impacts of a flood on the community

• once adopted The FRM Plan will open the doors to funding for Council • the recommended actions will inform council‟s capital works program • the plan will require ongoing active community involvement and engagement.

During the presentation the following matters were raised:

Mr Lyons explained that a lot of focus today is in and around measures and mitigation options that are recommended in the plan. Part of the plan review has been the plan update which includes the review of the previous Griffith Floodplain Management Plan completed in 2011. One of the drivers for this particular study has been an update of that part of the report largely to include the contributions of Mirrool Creek flooding through the Yenda environment, as the Committee has seen over the progression of the last few years and that has diverged into a full update of the flood study. Mr Lyons advised that there are still elements of the 2011 flood study that are appropriate to move forward with and there are other elements that


are superseded. A lot of the solutions and measure put forward are to address some of the local flooding issues hot spot areas in the study areas in Yenda, Yoogali and Hanwood.

• Councillor Rossetto enquired if in relation to Yoogali options - flood embankments/levy works if they impact on any homes. Mr Lyons advised that some areas are less than 0.1m (orange areas on map) and less than 5 cm (yellow area on map) and that this is not expected it to have any impact on residential properties.

Councillor Thorpe entered the meeting, the time being 1.30 pm

• Councillor Rossetto enquired how the dollar values were arrived at in terms of cost benefit values or whether perhaps they were drawn from insurance companies or from a register of damages.

• Mr Lyons advised that they are arrived at from construction costs and weighted in terms of likely flood events, and are based on flood study results OEH have generated. Mr Lyons stated that the value for damages is arrived from flood study results and that there is a relationship between the depth of flooding and damage value to properties (industrial, commercial and residential).

• Mr Gilbert stated that at the December meeting the rail bridge modification and rail cross drainage options was mentioned and enquired if and they no longer required. Mr Lyons advised that this was identified in earlier Committee meetings as a potential option and that there is a section in the updated report that relates to this and that making changes to those structures redundant may only have a minimal impact on flood levels. Mr Lyons stated that it was more so the actual capacity of Main Drain J driving levels and that there was very little head losses across the structure so even with an upgrade there would only be minimal improvements of less than 5 to 10 cm in terms of actual peak flood levels for these type of events and on that basis they have not been recommended to be pursued as there would be very little benefit derived.

• Mr Budd stated that the Committee’s minutes and correspondence talk about an MOU with MI and stated that should the levy be constructed it could be considered a flood control structure and that the MOU should give consideration to who should maintain the integrity of the structure. Mr Budd further stated that there should be a mechanism in place so that the issue is discussed with MI and that there is a proper course of action taken as to who is going to make sure it is not going to get damaged and if it is damaged who is going to pay to have it fixed. Mr Budd advised that Mr Borrows letter made it clear that flood structures are Council’s responsibility.

Mr Lyons agreed with Mr Budd’s comments and stated that works would be perceived as a formalised levy even to the point of how it is going to be constructed and funded. Mr Lyons stated that he anticipated that the NSW Government would fund the works and that it would be MI’s infrastructure in terms of long ongoing operation and maintenance and that should be included in the MOU and should be included in the plan’s recommendations.

• Ms Jones suggested that the levies be planted with vegetation in order to enhance the

aesthetics of the levies and enquired as to who would coordinator this, would it be MI or Council. Mr Lyons stated that this was a good idea and suggested it be taken up with Council’s planners and with MI.

• Councillor Zappacosta stated that a lot of the soil on channel banks has been taken away and banks reduced and in some cases banks are quite low. Councillor Zappacosta asked


Mr Gilbert if MI’s operations has resulted in some instances taking away soil to some other location. Mr Gilbert advised that MI has various maintenance practices in place, however MI is not licenced by the NSW Government to maintain bank heights at certain levels for flood mitigation purposes. Mr Gilbert further advised that MI attempt to ensure that they do not inadvertently affect the profile of the land however they do not go out and actively and ensure that farmers or anyone else is not disturbing the channel banks.

• Mr Budd commented that along the Yenda Road there used to be quite a substantial channel bank beside Main Drain J running all the way through to Beelbangera and Yenda that has been taken down quite substantially and it has beautified the area and the only place where it breached was near Yoogali. Instead a having a large bank that was difficult to keep clean of vegetation now there is a level area across to the road to the edge of the channel would looks much better and which resulted in only one breach point at Yoogali.

Mr Budd stated that is only a couple of points in the report where there is a possibility

where increasing the height of the channel bank could be an option.

• Mr Lyons stated that within Yenda there is a particular focus on the option for the upgrade of the flood structure escapes at the EMR and there are various configurations available for potential upgrade of this structure but broadly within the study itself and that ultimate objective is to remove or reduce the distribution of flow from the Mirrool Creek floodplain through to Yenda and to north Yenda which is essentially that cross catchment diversion into Main Drain J.

Councillor Rossetto stated that there was fundamentally a big difference between the

sluice gates structure and a siphon type structure in that the siphon type structure would be open all the time and the problem with the sluice gates on an irrigation channel is where you have irrigation water flowing through daily and in the event of a minor flood water can travel through the siphon structure without any problem.

Councillor Rossetto enquired where would the decision be made to open the sluice gates

and stated that before they are opened the irrigation water has to be stopped 3 or 4 days in advance as there would be a pipeline affect flowing down from Narrandera or from the various structures and therefore we cannot say for design purposes they are the same.

Mr Lyons agreed that there are fundamental differences and that the intent was to shift water – not to acknowledge there would be differences in there operation.

• Mr Budd enquired if at 1% ie 1:100 year flood event at 134.3m AHD which is what basically a channel bank is and with a 500mm freeboard, should works be done to improve the level for example increasing it to 1:200 year event and would that have an impact on the ability to apply for funding.

Mr Nankivell advised that this would have only a minor bearing on the application for funding.

• Councillor Croce asked how far along the Northern Branch Canal would the bank level of 134.8m AHD be maintained with Mr Lyons advising that it would be approximately 6 kms.

• Mr Forner enquired if soil would be brought in from other places to increase the bank levels or if it would be dredged out of the channel.

Mr Lyons advised that where the soil will come from at this stage has not been identified and that this would form part of the design process.


• Councillor Rossetto enquired if at the new operational level of 134.3 AHD if water would travel through the Binya State Forest, through the railway tracks and to north Yenda via Cemetery Road as it did during the 2012 flood event.

Mr Lyons advised that part of it would even though the level is a little different to the point where Binya Creek flows then splits and flows north again to Yenda which is more so to control the flows from Mirrool Creek proper heading north along the embankment. Councillor Rossetto stated that he didn’t think that it split the flow and that water was pooled up against the EMR and that once it found that level it travel through Binya State Forest, over the highway and over the railway tracks, blew through the track, then continued down Cemetery Road. Mr Lyons advised that the flow of water would still be pushed in that direction through to north Yenda.

Councillor Rossetto stated that it didn’t make sense to quarantine one half of Yenda whilst pushing more water to the other part of Yenda.

• Councillor Rossetto stated that by extending/raising the banks of the Northern Branch Canal another 3 or 4 kms in length that would give greater protection to north Yenda. Raising the Whitton Stock Route would result in holding back water in the Binya State Forest which would possibly become a storage areas rather than having to divert water around to north Yenda. Mr Lyons said that to provide storage, the railway embankment would have to be raised in that vicinity and that by raising 6 kms of the Northern Branch Canal was not long enough, this would only provide protection to Yenda township and divert water to north Yenda.

• Mr Budd stated that when looking at improving the flood immunity for Yenda there is a need to recognise that the flow of water cannot be stopped and let it flow to somewhere else which may cause a lot of damage elsewhere.

• Councillor Rossetto said that he believed there was a channel being constructed at the western end of Barren Box Swamp to cater for flood events and that it was no longer a matter of overfilling Barren Box Swamp causing flooding as MI have taken provision with landholders to have drainage run through that area.

Mr Gilbert stated that he didn’t believe that was correct and that if there is an increase in flow into Barren Box Swamp because of structural changes upstream, to have some modelling or ability to better understand the impacts would be useful.

Mr Lyons asked that if this information is available if it could be passed on outlining how it works in more detail.

• Ms Jones enquired as to what extent is Barren Box Swamp used as a flood mitigation measure.

• Councillor Rossetto stated that he was not happy with any scenario that increases the flood risk of half of Yenda for the betterment of the other side of Yenda and that in this regard it was not a viable option.

Councillor Thorpe left the meeting, the time being 2.16 pm.


• Mr Lyons advised that with the different options in the report, that the scale of impacts being spoken about are fairly minor and that in most parts of Yenda and north Yenda the options are improving the conditions.

• Mr Budd asked if when speaking about a siphon was Darren referring to the siphoning of Mirrool Creek under the main canal or was he referring to the Lawson syphon. Mr Lyons confirmed that he was referring to a Lawson syphon where the main canal is being siphoned and the Mirrool Creek is flowing through its natural course.

• Councillor Rossetto stated that you are dealing with a 100 year old structure which has concrete cancer and suggested that it needs to be looked at sooner rather than later and asked why a new siphon could not be incorporated which would serve two benefits. 1. would give security and peace of mind if the exiting 100 year old structure was to collapse and if it needed to be taken off line there would be a new siphon with the same capacity, and 2. if another siphon was built under the channel it would supplement minor flood flows, possibly in the order of 1:50 year event without interfering with the flow of water in the irrigation channel. Mr Lyons advised that this in an example of a myriad of mitigation options. Councillor Croce left the meeting, the time being 2.35 pm.

• Councillor Zappacosta asked that in relation to the EMR upgrade impacts if the study looked at potential flooding further downstream such as past Yoogali with Mr Lyons advising that the model area extends almost to Barren Box Swamp looking at impacts all the way along.

Councillor Croce returned to the meeting, the time being 2.37 pm.

• Mr Budd enquired if the maps in relation to colouring (minus 50mm or plus 50mm in relation to 1% event) could be calibrated so that people could see where it starts to lose floodwaters with Mr Lyons advising that this could be achieved.

• Ms Jones stated that the lower Mirrool Creek was listed on the directory of nationally important wetlands and it needs to be flooded and that a consideration is the environmental benefits potentially downstream and how that can be enhanced and that the quality of water coming down is also a major consideration.

Councillor Croce left the meeting, the time being 2.50 pm.


• Councillor Rossetto stated that as the Northern Branch Canal is a restricted channel there would be benefits in dredging it out rather than truck in dirt.

• Mr Budd enquired how many weeks of downtime is required for the maintenance of channels during the winter months with Mr Gilbert advising that it was around 6 weeks from late May to early August depending on winter watering.

Mr Budd commented that if there is a 6 week window for the channel being out of action then it would be almost impossible to construction a Lawson syphon given the extensive work that would be required and enquired if it would be better to explore options where work could take place outside the line of the existing embankment.

Councillor Rossetto left the meeting, the time being 3.03 pm.

• Mr Gilbert sought clarification from Mr Lyons on the reinstatement option, asking if he was referring to the reinstatement of only one structure, being the southern floodgate structure or the northern structure or both so that they actually work in parallel to convey the volume of water expected. Mr Lyons stated that he was referring to both structures and that there was no costings associated with the design of these options and that it would possibly be somewhere in the vicinity of $200,000 upfront to work out whether it is worth spending $2M for a different type of arrangement.

Councillor Rossetto returned to the meeting, the time being 3.07 pm.

• Councillor Rossetto stated that what he would like to see is a temporary channel being built on the inside of the bend or temporary pipes laid which could act as a temporary water source while the main works are done over a 12 month period and that he would like to see a job done that is going to take the area forward another 100 years.

• Councillor Rossetto enquired if rainfall alerts would be recommended for the East Mirrool catchment area with Mr Lyons advising that he has been looking at that.

The Chair thanked Mr Lyons for his presentation. The Chair advised that Councillor Rossetto has requested to show some photographs of a siphon that he feels would be more adaptable than the Lawson syphon.

The Chair called on Councillor Rossetto to present his photographs of the siphon (attached).

The following was noted:

13 photos of the Lawson syphon structure at Aljoe’s Creek at Deniliquin. Structure is 700 mtrs south of the Edward River, a Lawson siphon structure visited

by Councillor Rossetto last year at the conference held in Deniliquin. Is almost a twin to the Mirrool Creek main channel junction because the capacities

are very similar. Aljoe’s Creek is a dry creek so it only runs when there is a significant rain event. Mulwala canal is piped through two 12 foot barrels Mulwala canal at that point has a capacity of 2,400mgs per day which is similar to

the Yenda EMR. Mulwala canal has 4 gates, approx. 1.4mtrs x 2 mtrs deep which gives it the same

capacity as the main canal as the EMR at Yenda. Photos showed the headwall of the 2 barrels leading underneath the Aljoe’s Creek. Bridge pylons are approx. 6 mtrs apart, bridge is approx. 4 – 5 mtrs high.


Councillor Rossetto spoke to a neighbour who reported that during the 2012 floods water got to half way up the pylons.

The Chair thanked Councillor Rossetto for his presentation. • Mr Gordon gave an outline of where to from here stating that based on the presentation

today and the fact that the Committee have the final draft report and having viewed the presentation that the Committee would have the confidence in the document to recommend it be presented to Council for adoption and public exhibition.

• Mr Gordon advised that Council was planning a Councillor Workshop to be held at Yenda

on 19 May 2015 which would provide an opportunity for community consultation. Mr Gordon further advised that there would be a community forum during the public exhibition period and perhaps a session at the Library with the consultants and the community will also be given the opportunity to book a time with himself and other technical members of Council so that they will have the opportunity to ask questions and get responses.

• Mr Budd referred to page 46 of the document, stating that the document was a little

misleading in relation to the mapping where the changing in peak levels are mapped and that it would be beneficial to include a figure showing the actual flood levels.

• Mr Lyons noted Mr Budd’s comments that stated that he would check for consistency. • Mr Budd also commented on the topographical maps eg in Figure 7.1 Yoogali levy option,

saying that be believed a lot of people would struggle with understanding what the map is actually showing. Mr Budd stated that people may look at the map and think that is what is flooding when it is actually depicting the elevations of the land and suggested that the title of the map needs to be made clearer and state ‘topographical or height level of natural ground’. Mr Budd referred to the map legend (where there is a change of elevation) and suggested that instead of having the lowest level at the top, this be reversed so that the highest level is a the top.

• Mr Budd stated that he has a serious issue with the flood planning level, given that it is

1:100 year event (in the blue map at the back of the document) plus 500mm freeboard. Mr Budd said that this makes a staggering difference to properties in the Griffith area that are within the flood planning area and that in the teleconference there were comments about the flood planning area and how that may impact of insurance and the inclusion on 149 Certificates.

• Ms Jones enquired if it was possible to have two colours on the topographical maps, one

being the 1:100 year event and the other showing the 1:100 year plus the 500mm freeboard.

• Mr Budd referred to figure 7.6 (mapping in relation to Yoogali) showing change in peak

flood level, the area to the south of Mackay Avenue and C1 stating that he had concerns over C1. Figure 7.6 shows the change of flood level for the scenario of a levy bank for Yoogali and there is no change of water level south of Mackay Avenue however in C1 there is.


Mr Lyons noted Mr Budd’s concern and stated that he would check for consistency.

• Mr Gordon advised that to clarify the question about the flood planning level with the 500 mm freeboard, that the 500mm freeboard is included because there is a clause in the LEP – flood planning means the levels of 1:100 ARI flood event plus a .5m freeboard and that the LEP is a legal document that refers to the 500mm.

• Mr Gilbert enquired if the document goes out on public exhibition is there is enough

information that the public would understand that those in the flood planning area would potentially be affected by the insurance costs.

Councillor Rossetto advised that at the last meeting it was resolved to include this information in the rates notices and enquired if this had been done. Mr Gordon advised that an FMA Insurance information brochure was included in all rates notices.

• Councillor Rossetto stated that ratepayers needed to understand that the document is a

legal document, they have a choice to either build their houses up 500mm or pay the insurance and enquired if Council would have time to adjust the LEP given that there is still some other matters to be put to the government.

• Mr Budd stated that having a map showing what is inside and what is outside of the 1:100

year area would make a better document.

Mr Lyons agreed to incorporate the modification. • Mr Giovinazzo enquired if under the current arrangement, the 2011 flood map, if this

would have changed much and that it actually was a reduction in flood planning areas rather than an increase.

Mr Gordon advised that there is a lot less flood planning area due to the change in modelling.

• Councillor Rossetto made reference to what he believed to be ‘emotive language’ in

relation to prioritising works, and labelling of table columns as ‘low, medium, high etc’ and stated that some Yenda residents who may still be suffering financially from the flood see works labelled as ‘medium priority’ they may become a little upset.

• Mr Budd referred to the first sentence on page 26, “The total estimated flood damage to

occur in a 100-year ARI flood event is $7.9M, increasing to an estimated $85M worth of damage from the Extreme Flood” and questioned whether these figures were correct. Mr Budd asked whether $7.9M should be $28.196M and in an extreme flood $115M.

Mr Lyons agreed with Mr Budd’s comments.

• Mr Budd raised the matter of coloured boxes on page 89 in the ‘performance and

measures’ and asked if the box listed as high should be coloured green instead of brown.

Mr Lyons agreed with Mr Budd and would make the correction. • Ms Jones referred to the second paragraph in the ‘introduction’ where there is mention of

the two models and asked if there could be an explanation given of the differences of the two models.


Mr Lyons stated that rather than refer to the models themselves he could refer to it as ‘software’ and suggested the use the term “software”.

Ms Jones stated that there needs to be an brief explanation of why the two models are different.

Mr Giovinazzo left the meeting, the time being 3.59 pm. • Ms Jones stated that an option would be to automate the escapes from the MI system

because if there is an extreme rain event and conditions deteriorate you would not have to wait for it to dry out to go and open the escape, this could be carried out automatically.

Mr Gilbert stated that he was assuming it would be considered as part of the reinstatement but if it is a flood structure it wouldn’t be MI operating it, it would be operated by some other organisation who would assume that responsibility.

Mr Gilbert further stated that if it is escapes for irrigation purposes then he would expect MI to be operating those whether it’s a flood event or not but he was earlier referring specifically to those two escapes at the EMR, and that it should be MI who do those and they should have protocols in place to make sure those escapes are operating to reduce drainage issues downstream.

• Mr Budd stated the he was assuming there will be a press release once a decision is

made to place the document on public exhibition and believes it is important that somewhere in a press release that people are informed, particularly the people of Yenda that the event that took place in 2012 was the largest magnitude that has been recorded, being far bigger than 1956 event and that it was important to get that across and that the other important thing to get across to the people of Yenda is that, even if the EMR structure was operational Yenda still would have flooded and that the options in the document are to look at mitigating the problems.

Mr Gordon advised that the standard press release informs the public that the document is on public exhibition and that perhaps the above information could be included in a media release.

Mr Gilbert stated that he supported some sort of way that would explain the context in plain English to ensure people understood.

Peter Budd and Louie Forner MOVED the following RECOMMENDATION: That the Committee adopt the Griffith Main Drain J and Mirrool Creek Floodplain Risk Management Study and Plan and present it to the Ordinary Meeting of Council to be held on 12 May 2015, following which the document be placed on public exhibition for a period of 42 days with a number of minor changes (Appendix D and the Glossary) should it be necessary subject to discussion between Mr Gordon and Mr Lyons following what has been discussed at today’s meeting. • Mr Gordon explained that the Committee would have an opportunity to look at revised

document before it is finally adopted. • Councillor Rossetto asked Peter Nankivell if the exhibition period extends to 42 days if

this would affect any timing for application for some funding before the end of June.

Mr Nankivell advised that there would be no funding opportunity at this point of time. Once Council have solid figures supported by the plan, Council will be able to put in an application for 2016/17 in February/March 2016.


• Mr Budd enquired if given that we have a scenario where the decommissioning of the EMR structure which appears to have been carried out by state government bodies as opposed to MI – resulting in the reduction to the immunity level for Yenda whether this would give leverage in relation to getting funding to get it fixed

Mr Nankivell stated that he didn’t think this would be the case.

• Councillor Rossetto stated that he strongly recommended that the emotive statements be

excluded in the media release, as he believes that Yenda people are ‘over it and just want to get on with it’.

Councillor Paul Rossetto and Sally Jones MOVED the following AMENDMENT: That given the in-depth discussions this Committee has had at today’s meeting the Griffith Main Drain J and Mirrool Creek Floodplain Risk Management Study and Plan be accepted by the Committee and presented to the Ordinary Meeting of Council to be held on 26 May 2015, following which the document be placed on public exhibition for a period of 42 days with a number of minor changes (Appendix D and the Glossary) should it be necessary subject to discussion between Mr Gordon and Mr Lyons following what has been discussed at today’s meeting. The AMENDMENT was PUT and CARRIED. RECOMMENDED on the MOTION of Councillor Paul Rossetto and Sally Jones: That given the in-depth discussions this Committee has had at today’s meeting the Griffith Main Drain J and Mirrool Creek Floodplain Risk Management Study and Plan be accepted by the Committee and presented to the Ordinary Meeting of Council to be held on 26 May 2015, following which the document be placed on public exhibition for a period of 42 days with a number of minor changes (Appendix D and the Glossary) should it be necessary subject to discussion between Mr Gordon and Mr Lyons following what has been discussed at today’s meeting. Mr Lyons left the meeting, the time being 4.20 pm. Mr Lyons returned to the meeting, the time being 4.22 pm. Discussion took place on what should be included in a media release, whether or not it should be a standard media release advising the public that the document is public exhibition, where to obtain a copy, its availability and for how long or whether it should be a more complex media release as discussed earlier.


Peter Budd and Sally Jones MOVED the following RECOMMENDATION: That a detailed media release be issued advising the public that the Griffith Main Drain J and Mirrool Creek Floodplain Risk Management Study and Plan is on public exhibition including information regarding the flooding of Yenda in 2012. Councillor Paul Rossetto and Louie Forner MOVED the following AMENDMENT: That a standard media release be issued to advise the public that the Griffith Main Drain J and Mirrool Creek Floodplain Risk Management Study and Plan is on public exhibition. The AMENDMENT was PUT and LOST RECOMMENDED on the MOTION of Peter Budd and Sally Jones: That a detailed media release be issued advising the public that the Griffith Main Drain J and Mirrool Creek Floodplain Risk Management Study and Plan is on public exhibition including information regarding the flooding of Yenda in 2012. Mr Gordon advised that at the Council Meeting held on Tuesday 28 April 2015 there was a notice of motion for Council to include $150,000 in the next financial year’s budget for the purpose of design work at the Yenda EMR. Mr Gordon confirmed that the two thirds funding from OEH was not available for the 2015/16 financial year as funding submissions had closed. Mr Nankivell from OEH also confirmed this. 6 OUTSTANDING ACTION REPORT RECOMMENDED on the motion of Peter Budd and Councillor Dino Zappacosta that the Outstanding Action report be noted.

Meeting of 4 December 2014 – CL07 – General Business – Correspondence from MI

Councillor Rossetto stated that he would like to congratulate Mr Gordon on the very strong letter to Mr Borrows. Mr Gordon advised that a response to his letter was received late on Wednesday afternoon. Mr Gordon distributed copies of the letter to the Committee (copy of letter attached). Matter finalised – to be removed from Outstanding Action Report.

Mr Budd enquired if it is possible to explore options of whether there can be an emergency protocol for blowing out the banks or something similar given that funding is now out of the question for the next financial year as the circumstance where Yenda’s flood immunity is reduced.

Mr Gordon stated that we could work with MI with the protocals and operational issues that MI would have in place if in an emergency centre, SES made the decision to breach the bank/s.

Mr Gordon further advised that it is in the report as an option and that Council can work with the key stakeholders to put a formal MOU in place that can be called upon as a protocol in a event of an emergency.

Mr Gilbert advised that MI would be happy to explore such options but noting that it is a major supply channel and restoration of supply to customers who have contracts with MI to supply would be an issue.

Mr Gordon stated that Griffith City Council is an important customer of MI and the town water supply is a priority.


Ms Jones enquired if protocols in dealing with an emergency situation such as the 2012 flood event could be tabled at the next committee meeting..

Mr Gordon advised that with the operation of an emergency operation centre the State Emergency protocol through our emergency response plans is the protocol.

Mr Gordon further advised that should there be an event like the 2012 flood event today, Council would have more information than what was available during 2012 and Council would draw on that information. Mr Gordon advised that he would be happy to bring back to the next meeting an Emergency Response Plan to show what the protocols are.

Mr Gilbert left the meeting, the time being 4.40 pm.

Mr Gilbert returned to the meeting, the time being 4.42 pm.

Ms Jones asked that having received this report what would be done differently in the event of a major flood and enquired if the Committee could be given a list of what things/protocols that would be included in an MOU.

Mr Forner left the meeting, the time being 4.43 pm.

The Chair stated that we cannot have protocols made up with a series of hypotheticals and in reality there is always going to be a different set of circumstances or different intensity. The Chair advised that he didn’t think we needed to produce a document that is going to anticipate and make decisions now about a series of future hypothetical circumstances.

Councillor Rossetto stated that he has read the SES Emergency Protocols and the reason they took over responsibility for the 2012 flood was because it reached one of their level 1 criteria which is greater than 3 metres in depth and that once flood waters reach that level it then becomes a risk and triggers the SES protocol. Councillor Rossetto further stated that whether the protocols are the same as in 2012 or whether they have been adjusted to accommodate local knowledge since the 2012 flood we do not know for sure and that he would be interested in finding this out. The other aspect that Councillor Rossetto would be interested in finding out is furthering the MOU with MI and understanding it because if it doesn’t trigger an SES overview it is just Council and MI working together to mitigate the flood.

Councillor Rossetto enquired what would happen between Council and MI and at what point would the SES come into play if 4 inches of rain was to occur within 48 hours and trigger an overflow of the Northern Branch Canal.

Mr Gordon advised that this can be explored with the SES.

Mr Forner returned to the meeting, the time being 4.45 pm.

RECOMMENDED on the motion of Councillor Paul Rossetto and Sally Jones that a report be brought back to the next Committee meeting in relation to emergency protocols during a major flood event.

7 GENERAL BUSINESS

7.1 Community Forum during Public Exhibition of the Report

Item 7.1 was discussed earlier in the meeting.

7.2 FMA National Conference Brisbane – May 2015


Mr Gordon advised that the Floodplain Management Association Conference will be held in Brisbane on 19, 20 and 21 May 2015. This year’s theme is “Building a Flood Resilient Australia”, which will focus on building resilient communities and flood resilient buildings and infrastructure.

Queensland's extensive floods, impressive response and recovery programs, and current flood mitigation projects will provide excellent learning which can be applied across Australia. To ensure the conference is relevant at national as well as individual state and territory levels it is guided by a Program Advisory Committee with representatives from every state and territory.

The conference program will include outstanding Australian and international keynote speakers, over 50 presentations to choose from, a Local Government Councillors' session, the National Conference Forum, field trips addressing floodplain issues in the Brisbane River catchment, and networking events.

The Chair enquired if Councillor Rossetto would like to represent Council at the conference.

Mr Gordon advised that the minutes of this meeting would not be presented to Council for consideration until the Ordinary Meeting of Council on 26 May 2015.

7.3 Letter sent to Mr Peter Borrows, MI – 1 April 2015

This matter was discussed in Clause 06 – Outstanding Action Report.

7.4 Cost Benefit Analysis

Mr Gilbert asked Mr Nankivell if he was able to comment on cost benefit analysis in particular as it is an influencing factor in assessing funding applications.

Mr Nankivell advised that it is a factor but not a heavily influencing factor, benefit cost ratio is one of many items considered on the new works ranking form that accompanies the application form.

Mr Chaudhary left the meeting, the time being 4.47 pm.

Mr Chaudhary returned to the meeting, the time being 4.48 pm.

Mr Rizzo left the meeting, the time being 4.50 pm.

Mr Rizzo returned to the meeting, the time being 4.52 pm.

Mr Nankivell outlined the funding process in relation to the receival and assessment of funding applications.

6 NEXT MEETING

Mr Gordon stated that the next is scheduled to be held on 9 July and thought that perhaps this would be too soon following the public exhibition period.

Mr Gordon will be an apology for the 9 July meeting.

The next meeting of the Floodplain Management Committee is to be held on Thursday 6 August 2015 at 1.00 pm in the Council Chambers.

Mr Budd enquired if it would be worthwhile as a Committee in taking a bus and inspecting some of the areas to have a better understanding of what has been discussed, for example McCormack Road and the Northern Branch Canal Levy.


Mr Gordon stated that an inspection by bus could be coordinated prior to the next meeting, to commence at 1.00 pm.

Mr Gilbert advised that any MI specific areas would need to be coordinated with MI.

There being no further business the meeting terminated at 4.55 pm.

Confirmed: ..........................................

CHAIRPERSON


Copy of photographic presentation made by Councillor Rossetto


Griffith City Council REPORT CLAUSE CL01 TITLE Presentation & Report - Darren Lyons - Griffith Main Drain J & Mirrool

Creek Floodplain Risk Management Study & Plan - Response to Submissions received during public exhibition of the report

FROM Graham Gordon, Director Utilities TRIM REF 15/50218 SUMMARY

At the previous meeting of the Floodplain Management Committee held on 30 April 2015 the Committee recommended the following:

“That given the in-depth discussions this Committee has had at today’s meeting the Griffith Main Drain J and Mirrool Creek Floodplain Risk Management Study and Plan be accepted by the Committee and presented to the Ordinary Meeting of Council to be held on 26 May 2015, following which the document be placed on public exhibition for a period of 42 days with a number of minor changes (Appendix D and the Glossary) should it be necessary subject to discussion between Mr Gordon and Mr Lyons following what has been discussed at today’s meeting”.

Council adopted the minutes of the Floodplain Management Committee Meeting of 30 April 2015 at its Ordinary Meeting of Council held on 26 May 2015 following which the Draft Main Drain J and Mirrool Creek Floodplain Risk Management Study and Plan was placed on public exhibition for 42 days commencing 29 May 2015.

A number of submissions were received during the public exhibition period. The submissions were forwarded to BMT WBM for a response to be prepared.

Attached to this report is the responses prepared by Darren Lyons, BMT WBM for each of the submissions received (refer to the attachments).

RECOMMENDATION

For the Committee’s determination.

ATTACHMENTS

(a) Response to submission received from R Zalunardo 34

(b) Response to submission received from Carrathool Shire Council 41

(c) Response to submission received from P Pietroboni 44

(d) Response to submission received from G & R McKenzie 45

(e) Response to submission received from Yenda Flood Victims Ass. Inc. 46

(f) Response to submission received from B Taylor 48


(g) Response to submission received from G Forner 49

(h) Response to submission received from M & J Bianchini 50

(i) Response to submission received from Yenda Progress Association 51

(j) Response to submission received from J Bisetto 53

(k) Response to submission received from G & S Walters 54

(l) Response to submission received from M Forner 55

(m) Response to submission received from P & R Calabria 56

(n) Response to submission received from G Cannard 57

CL01 Attachment (a) Response to submission received from R Zalunardo


CL01 Attachment (b) Response to submission received from Carrathool Shire Council


CL01 Attachment (c) Response to submission received from P Pietroboni


CL01 Attachment (d) Response to submission received from G & R McKenzie


CL01 Attachment (e) Response to submission received from Yenda Flood Victims Ass. Inc.


CL01 Attachment (f) Response to submission received from B Taylor


CL01 Attachment (g) Response to submission received from G Forner


CL01 Attachment (h) Response to submission received from M & J Bianchini


CL01 Attachment (i) Response to submission received from Yenda Progress Association


CL01 Attachment (j) Response to submission received from J Bisetto


CL01 Attachment (k) Response to submission received from G & S Walters


CL01 Attachment (l) Response to submission received from M Forner


CL01 Attachment (m) Response to submission received from P & R Calabria


CL01 Attachment (n) Response to submission received from G Cannard



Griffith City Council OUTSTANDING ACTION REPORT TITLE Outstanding Action Report TRIM REF 15/49884 RECOMMENDATION

The report be noted by the Committee.

ATTACHMENTS

(a) Outstanding Action Report as at 30 April 2015 59

6 Attachment (a) Outstanding Action Report as at 30 April 2015


agenda of floodplain management committee - 6 august … · the report he was disappointed that the...

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