Managing Council’s Road Network for Better Outcomes

Storm Damage ExperienceIan de Bruyne

Manager Program Planning & DeliveryIPWEA Regional Forum

15 May 2012

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Council’s Road Network• Total Road Network Length 1791 km• Sealed Roads 1020 km• Gravel Roads 771 km

• Collector Roads sealed 440 km• Collector Roads unsealed 54 km.

• Local Roads sealed 580 km• Local Roads unsealed 717 km.

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Council’s Road network

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Council’s Road network

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Storm Damage

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• 240 storm affected sites• 140 of these are listed as landslips• 3 landslips categorised as severe• 26 landslips categorised as major• 100 sites on the road network were storm

affected (washouts, pavement erosion, mud on road, fallen trees etc)

• 24 gravel roads totalling 76km were damaged requiring resheeting

March 2011 Storm Event

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Feb 2011 RainfallWeather and factors leading up to the start of major landslips:

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March 2011 RainfallWeather and factors leading up to the start of major landslips:

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February March 2011 Rainfall

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Total Feb & Mar 2011 rainfall of 332mm

13 Year Feb Mar Rainfall Profile

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20002001

20022003

20042005

20062007

20082009

20102011

20120

50

100

150

200

250

300

350

38

11994 90

57

144

59

10582

58

142

332

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Feb and March Rainfall Totals

Year

Rain

fall

(mm

)

Response

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• Erect barricades and warning signs to, make damaged roads safe for traffic . Fully or part closed roads which required major reinstatement work.

• Cleaned up the debris along the affected roads, clean drains • Engaged Consultants to carry out road safety audits on the

landslip/storm affected roads who recommended further treatments in order to ensure the safety of road users.

• Liaise and inspect storm damaged site with Vic Roads. Keep data base of damaged sites (use GPS camera)

• Keep Public informed of extent of damage and plans for reinstatement – public meetings, letter drops, media releases, Council website.

Storm Damage Cost

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• Estimated total cost for the reinstatement works is $11.4 million

• Landslip estimates cost $9.4 million

• Resheet storm damaged roads $2 million

• Request for 50% of the estimated cost as advance payment for the reinstatement works was made to the Treasury.

• Treasury funded an advance payment of $5.6million

Recovery

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• Consultants engaged to investigate each of the severe and major

landslip sites, prepare preliminary concept designs and estimates for proposed reinstatements

• Continue monitoring progression of landslips and slumps

• Public meetings to keep the public of the issues and impending activities to reinstate damaged roads

• Attend to minor reinstatements

• Seek up front natural disaster funding from State Treasury

• Tender for the repair of severe and major landslips

Causes of Damage• Weather factors - cumulative and intense rainfall events• Fissured ground after long period of dry weather• Steep terrain• Steep dissected slopes (roads)• Slope stability• Reactive soils (montmorillonite, haloysite)• Soil moisture saturation• Inadequate table drain and under road culvert maintenance

– tree litter, road debris

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Reinstatement Treatment Options

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Landslips• Reinforced earth walls• Gabion walls• Extruded Polystyrene

Slumps• Reinforced earth walls• Gabion walls

Extruded Polystyrene Treatment

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Gabion Wall Treatment

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Inadequate Drainage Maintenance

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Gabion Wall

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Extruded Polystyrene

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Gabion Wall

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Reference

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"A Study of Landslides and their Relation to Engineering and Planning in the Southern Districts of the Narracan Shire, Victoria (1979)“• Examines the nature and distribution of

landslides, the properties of the soils involved and the factors responsible for slope instability.

• Provides suggestions for mitigating the existing and potential landslide hazards.

• Study undertaken by J.C. Brumley of the former Department of Minerals and Energy in 1978. Final report was prepared as part of an Unpublished Report series http://vro.dpi.vic.gov.au/dpi/vro/wgregn.nsf/pages/wg_landwtrmgmt_degrad_narracan

Learnings from our ExperienceMaintenanceRegularly maintain, especially during the drier seasons:• Table drains and under road culverts • Road shoulders• Remove tree litter not only in table drains or road shoulders

but also on slopes on the high side of the road• Use GPS cameras to record damageCommunications• Meet with communities or people affected by the damage• Issue regular status and progress updates.• Keep Council informed of progress or blockages

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End

Thank you for your attention

Any Questions?

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