Road Controlling Authorities Forum 27 th April 2012 Network resilience: update on opening the Gorge
WHERE IS IT? OPOTIKI SLIP GISBORNE
THE ISSUES WITH THE GORGE The gorge cuts through ranges of steep sided hills rising from 400 metres near the coast to 1000 metres inland The 57 km of the Waioeka Gorge consists of crushed and weathered greywacke rock and is immensely unstable The Gorge terrain is dissected by numerous fault crush zones which produce the larger slips. The SH at the slip site follows the incised valley cut by the Opato Stream i.e. very narrow The nature of the greywacke means that the slip material has moved some 25mm since the 3 rd March (as at 18 April)
THE HISTORY OF CLOSURES Waioeka Gorge Closures (2007 2012) 0 2 4 6 8 10 12 14 16 1/01/2007 1/02/2007 1/03/2007 1/04/2007 1/05/2007 1/06/2007 1/07/2007 1/08/2007 1/09/2007 1/10/2007 1/11/2007 1/12/2007 1/01/2008 1/02/2008 1/03/2008 1/04/2008 1/05/2008 1/06/2008 1/07/2008 1/08/2008 1/09/2008 1/10/2008 1/11/2008 1/12/2008 1/01/2009 1/02/2009 1/03/2009 1/04/2009 1/05/2009 1/06/2009 1/07/2009 1/08/2009 1/09/2009 1/10/2009 1/11/2009 1/12/2009 1/01/2010 1/02/2010 1/03/2010 1/04/2010 1/05/2010 1/06/2010 1/07/2010 1/08/2010 1/09/2010 1/10/2010 1/11/2010 1/12/2010 1/01/2011 1/02/2011 1/03/2011 1/04/2011 1/05/2011 1/06/2011 1/07/2011 1/08/2011 1/09/2011 1/10/2011 1/11/2011 1/12/2011 Date Closure Duartion (hours) Of these 11 gorge closures over the last 5 years, slips have been a direct cause of closure 7 times. The other four closures were caused by snowfalls or vehicular roll overs Last big closure (several weeks) was in July 1998 Contractor resources based in Opotiki to service the gorge Slip Slip Slip Slip Slip Slip Slip
WHAT HAPPENED? FRIDAY 2ND MARCH: Slip consisting of some 10,000m³ of soil occurs in the morning Road closed to allow for removal operation SATURDAY 3RD MARCH: Secondary, much larger slip occurs at 5:00pm bringing down approx 100,000m³ of soil near Sandy s Bridge Of this, some 30,000m³ of material created a rocky outcrop over the state highway а of the way up the slip Road closure continued indefinately
PROCESS FOR FIXING Week 1 Investigated and initiated safe methods to break down the rocky outcrop and stabilise the slip Week 2 Removed overhanging material at rocky outcrop; commenced slip removal operation Week 3 Commenced removal of material to local temporary disposal site and started to construct temporary access Week 4 Opened road to allow for one lane access during daylight hours and continued to stabilise slip face by removing loose material Week 5+ Opened road to allow for one lane access 24 hours a day and started construction of access track up the face to enable team to remove the rocky outcrop
IMPORTANCE OF OPENING Alternative routes via SH35 around the East Cape and SH5 through Taupo adding an additional 2.5 hours travel time per one way journey Local road alternative (Motu Road) not suitable for detouring traffic closed Significant impact on businesses due to the increased travel times and loss of direct route between Opotiki and Gisborne Significant impact on Gisborne tourism market Significant Impact on locals residents
COMMUNICATIONS AND FRONTING UP Treis updated immediately Detours set up via SH 35 and SH 5 Additional VMS signs put in place on SH2 at Paengaroa and on SH 30 east of Rotorua Dedicated website set up Media releases issued every second day Stakeholder list established and daily updates issued Radio and newspaper interviews conducted Meeting held with affected transport operators Numerous site visits conducted
LOOKING FORWARD Continue work with excavation machines to remove the 30,000 cubic metres of slip material from the middle of the slip face (expected to take up to four weeks weather dependant) Move to clear the state highway of slip material Repair damage to the state highway Reopen fully to two lanes
A VISUAL PERSPECTIVE A VISUAL PERSPECTIVE
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