Axtec Limited · ASX:AXI
Axtec — Axiom Properties — Technical Presentation (August 2003)
32 slides from Axtec's technical presentation, Aug 27, 2003
Slide 1: Port Geographe Presentation to Shire of Busselton
Port Geographe Presentation to Shire of Busselton on 27 August 03 by Mick Rogers Principal Coastal Engineer M P Rogers & Associates Pty Ltd M P ROGERS & ASSOCIATES 1 Coastal & Port Engineers
Slide 2: East Busselton Coast: Port Geographe & Wonnerup
East Busselton Coast Port Geographe & Wonnerup ¾ Studies & Experience with Coastal Processes at East Busselton 9 History of erosion – Guerin Street Groyne built to protect area to west 9 Guerin Street Groyne caused significant erosion to east including Wonnerup Beach 9 About 50,000 m3/yr of sand mix
Slide 3: Accretion and erosion caused by Guerin Street Groyne
Accretion caused by Guerin Street Groyne Erosion caused by Port Geographe Guerin Street Site Groyne M P ROGERS & ASSOCIATES 3 Coastal & Port Engineers
Slide 4: Fundamentals of Sediment Movement
Fundamentals of Sediment Movement M P ROGERS & ASSOCIATES 4 Coastal & Port Engineers
Slide 5: Fundamentals of Sediment Movement
Fundamentals of Sediment Movement ¾ During the action of wave breaking, the sand is stirred up and put into suspension ¾ The wind, tidal and currents caused by waves breaking at an angle to beach move the sand along the beach – most of the movement is in the wave breaking zone ¾ The magnitude and di
Slide 6: Fundamentals of Sediment Movement
Fundamentals of Sediment Movement ¾ Breakwaters and dredged channels interrupt this movement along the beach ¾ There is accumulation on to the west (updrift side) and erosion to the east (downdrift side) ¾ There is also accumulation in the dredged channel causing the channel to shoal and this can ef
Slide 7: Sand movement diagram: erosion and accretion
50,000 m3/yr Erosion Accretion 50,000 m3/yr M P ROGERS & ASSOCIATES 7 Coastal & Port Engineers
Slide 8: Seagrass Wrack Dynamics
Seagrass Wrack Dynamics ¾ Seagrass plants loose some of their leaves each winter due to biological response and the increased hydrodynamic forces from winter storms and swells ¾ The seagrass wrack can be close to neutrally buoyant and float in the surface layer of the ocean ¾ The surface layer of th
Slide 9: Seagrass wrack floating and easily moved by currents
Seagrass wrack floating and easily moved by currents M P ROGERS & ASSOCIATES 9 Coastal & Port Engineers
Slide 10: Seagrass Wrack Dynamics
Seagrass Wrack Dynamics ¾ Simple estimates indicate that about 300,000 m3 of seagrass wrack can form on the beaches ¾ This is a natural process and occurred prior to the construction of Port Geographe ¾ The change in wind, wave and water level conditions in late spring and summer can clear some of t
Slide 11: M P ROGERS & ASSOCIATES Coastal & Port Engineers
M P ROGERS & ASSOCIATES 11 Coastal & Port Engineers
Slide 12: Port Geographe
Port Geographe ¾ Initial plan by Kinhill Riedel & Byrne was to excavate a very large trap area every few years ¾ This was tried in 1998 and filled very quickly with seagrass wrack ¾ Some of this wrack has been covered by sand ¾ This approach failed because the trap filled with seagrass wrack rather
Slide 13: Aerial Photograph May 1998: Large Trap Dredged
Aerial Photograph May 1998 Large Trap Dredged M P ROGERS & ASSOCIATES 13 Coastal & Port Engineers
Slide 14: Aerial Photograph December 1998
Aerial Photograph December 1998 Trap filled with seagrass wrack & sand M P ROGERS & ASSOCIATES 14 Coastal & Port Engineers
Slide 15: Seagrass wrack being covered by sand in 1998
Seagrass wrack being covered by sand in 1998 M P ROGERS & ASSOCIATES 15 Coastal & Port Engineers
Slide 16: Aerial Photograph April 2001
Aerial Photograph April 2001 Note dredge working in trap area M P ROGERS & ASSOCIATES 16 Coastal & Port Engineers
Slide 17: August 2003 photograph of trap area
August 2003 photograph of trap area M P ROGERS & ASSOCIATES 17 Coastal & Port Engineers
Slide 18: August 2003 photograph of trap area
August 2003 photograph of trap area M P ROGERS & ASSOCIATES 18 Coastal & Port Engineers
Slide 19: Port Geographe
Port Geographe ¾ Beach monitoring has been completed over the years since Port Geographe was constructed ¾ Despite the bypassing completed, sand and seagrass wrack has accumulated to the west of the breakwaters ¾ There is a need to bypass larger quantities of material (a sand and seagrass wrack mixt
Slide 20: Key Issues Regarding Bypassing
Port Geographe Key Issues Regarding Bypassing ¾ There is limited equipment available capable of handling the sand / seagrass mixture ¾ The suitable equipment has limitations on the sea conditions in which it can safely operate ¾ The seagrass wrack does tend to clear from the west during late spring
Slide 21: Consultative Committee
Port Geographe Consultative Committee ¾ A Consultative Committee has been formed in accordance with the project approvals from the State Government and the Shire of Busselton ¾ There are members on this committee from the 9 Shire of Busselton 9 Department for Planning & Infrastructure 9 Department o
Slide 22: Current Bypassing Proposals
Port Geographe Current Bypassing Proposals ¾ Shire of Busselton requested that 100,000 m3 of material be bypassed in September and October 2003 ¾ Axiom advertised by public tender Australia wide – 17 sets of tender documents issued including several to contractors based in other states ¾ The tender
Slide 23: Bypassing Objectives In Light of Tenders Received
Bypassing Objectives In Light of Tenders Received ¾ Work with nature to minimise the amount of seagrass to be bypassed, ie start work in late September when nature has dispersed some of the seagrass wrack although late storms may return some wrack ¾ Bypass about 100,000 m3 of material as part of pro
Slide 24: Current Bypassing Proposals
Port Geographe Current Bypassing Proposals ¾ VMS Contractors have offered on a schedule rates basis to use land based equipment to bypass sand / seagrass wrack ¾ The offer is really a trial of equipment ¾ The equipment would include 9 Swamp dozer 9 Hydraulic excavator 9 Front end loader 9 3 or 4 Sem
Slide 25: Current Bypassing Proposals
Port Geographe Current Bypassing Proposals ¾ VMS can start in September ¾ Propose to proceed with trial and move about 60,000 m3 of material ¾ Pick up on beach to the east of Groyne Road and shape the beach to enhance the natural dispersion of the seagrass wrack ¾ Dispose material on eastern breakwa
Slide 26: Aerial photograph: VMS extraction and disposal areas
Aerial VMS disposal Photograph area April 2001 VMS extraction area M P ROGERS & ASSOCIATES 26 Coastal & Port Engineers
Slide 27: Current Bypassing Proposals
Port Geographe Current Bypassing Proposals ¾ Total Marine Services have tendered on a schedule of rates basis to use the dredge Sandpiper to bypass sand / seagrass wrack ¾ The offer is with proven equipment ¾ The equipment would include 9 Floating dredge 9 Crane 9 Booster pump 9 MDPE pipeline ¾ Equi
Slide 28: Current Bypassing Proposals
Port Geographe Current Bypassing Proposals ¾ Total Marine Services should be able to start in November ¾ Propose to move about 40,000 m3 of material ¾ Pick up on beach between Groyne Road and the marina entrance and in the marina entrance if needed ¾ Dispose material on eastern breakwater ¾ Cost abo
Slide 29: Aerial photograph: Total Marine Services extraction areas
Total Marine Aerial Services’ disposal Photograph area April 2001 Total Marine Services’ extraction areas M P ROGERS & ASSOCIATES 29 Coastal & Port Engineers
Slide 30: Current Bypassing Proposals
Port Geographe Current Bypassing Proposals ¾ Tender received from CGC Dredging offered floating dredge with significant qualifications concerning blockages and delays ¾ This dredge is unproven in this situation and may cost more than the other options ¾ Alternative equipment – Slurrytrak was also of
Slide 31: Current Bypassing Proposals
Port Geographe Current Bypassing Proposals ¾ Total cost of 2003/04 bypassing about $700,000 ¾ Work with nature as much as practicable ¾ Minimise impact on local community ¾ Trial new equipment and work methods ¾ Trial VMS using trucks on beach to move about 60,000 m3 of material in September to Xmas
Slide 32: Likely Outcomes of Proposed Bypassing
Port Geographe Likely Outcomes of Proposed Bypassing ¾ Operational experience on a range of equipment and methods for the long term management of the system ¾ Marina entrance maintained for small boat navigation ¾ Large amount of material placed on eastern beach to provide beach and protection ¾ Rem
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