Managing Council’s Road Network for Better Outcomes Storm Damage Experience Ian de Bruyne Manager Program Planning & Delivery IPWEA Regional Forum 15 May

Council’s Road Network Total Road Network Length1791 km Sealed Roads1020 km Gravel Roads771 km Collector Roads sealed 440 km Collector Roads unsealed 54 km. Local Roads sealed580 km Local Roads unsealed 717 km. 2

Council’s Road network 3

4

Storm Damage 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 6

Feb 2011 Rainfall Weather and factors leading up to the start of major landslips: 7

March 2011 Rainfall Weather and factors leading up to the start of major landslips: 8

February March 2011 Rainfall 9 Total Feb & Mar 2011 rainfall of 332mm

13 Year Feb Mar Rainfall Profile 10

Response 11 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 12 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 13 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 14

Reinstatement Treatment Options 15 Landslips Reinforced earth walls Gabion walls Extruded Polystyrene Slumps Reinforced earth walls Gabion walls

Extruded Polystyrene Treatment 16

Gabion Wall Treatment 17

Inadequate Drainage Maintenance 18

Gabion Wall 19

Extruded Polystyrene 20

Gabion Wall 21

Reference 22 "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. 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. 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 Final report was prepared as part of an Unpublished Report series wg_landwtrmgmt_degrad_narracan Study undertaken by J.C. Brumley of the former Department of Minerals and Energy in Final report was prepared as part of an Unpublished Report series wg_landwtrmgmt_degrad_narracan

Learnings from our Experience Maintenance Regularly 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 damage Communications Meet with communities or people affected by the damage Issue regular status and progress updates. Keep Council informed of progress or blockages 23

End Thank you for your attention Any Questions? 24