A useful Power Point by Paul Truong

VETIVER GRASS SYSTEMFOR INFRASTUCTUREDr. Paul TruongVeticon Consultingwww.uqconnect.net/veticonAll materials in this document remain the property of Veticon Consulting PtyLtd. Permission must be obtained for their use. Copyright © 2010

INTRODUCTION• The Vetiver System (VS) is based on the use of vetiver grass (Vetiveriaizizanioides L.) for a wide range of applications.• VS was first developed by the World Bank for soil and waterconservation and now being used in over 100 countries. In QueenslandVS was developed by the Department of Natural Resources for soilerosion and sediment control, land stabilisation and effluent disposal.• Vetiver grass is a native of the Indian sub-continent which wasintroduced to Queensland from Fiji since early in the 1900s. A sterilecultivar was selected and registered to the DPI as Monto vetiver inQueensland. Monto vetiver is sterile, non invasive, it flowers but set noseeds hence no weed potential.• R&D conducted by DPI and DNR showed that Monto vetiver is tolerantto the most adverse conditions, high levels of pesticides and herbicidesand also to a wide range of heavy metal toxicities. Therefore VS hasbeen successfully used for environmental protection purposes inAustralia, Asia, Africa and Europe.

TOPICS OF TODAY PRESENTATION1- Introducing Vetiver Grass• Its extraordinary attributes2- Infrastructure Protection• Road and Highway batters• Dam walls• River and stream bank erosion control

Introducing Vetiver grassUNIQUE MORPHOLOGICALCHARACTERISTICS OFMONTO VETIVERSiff Stiff and erect shoot growth

Erect stems upto 2m tall andover 2.5m withflower head

Forming a thick hedge when planted in row

Introducing Vetiver grassUNIQUE MORPHOLOGICALCHARACTERISTICS OFMONTO VETIVERMassive, deep and penetratingroot system

China: One year old with 3.3m deep rootsystem(These roots have a tensile strength equivalent to1/6 mild steel reinforcement)Australia: One yearold, 1.3m and rootbound

Infrastructure Protection• Research on tensile and shear strength of the rootgsystem• Road and Highway batters• Dam walls• River and stream bank erosion control

Soil stabilisation mechanism by vetiverVetiverhedgerowsVti Vetiverrootsslipping zone on slopesusually 0~2 m depthsDiti Hengchaovanich

Shear test of vetiver roots

(These roots have a tensile strengthequivalent to 1/6 mild steelreinforcement)

Strong root reinforcement holding up this wall of soil againstwater erosion

RootsExtensive rootdistribution atdepth of this amwall

Infrastructure ProtectionSome examples of works in Qld and Overseas• Road and Highway batters

Teemburra Dam Access Road Mackay Trial conducted by the DeptEnvironment and Heritage

After 400mm of rain in 10 days

One and half year after planting

Lakeland – Laura Road(At Split Rock )Batter Stabilisation

CAPE YORKPENINSULARLakeland – Laura Road(At Split Rock )Severe erosion onunprotected cut slope

This concrete shute will collapse due to severe erosionand undermining.

Completely stabilised seven months after planting

Hydromulching seven months after planting

Cooktown-Lakeland RoadStabilisation of road batters

Batter protected by vetiver contour planting at between 0.5 and 1.0mVertical Interval, Three weeks after planting

Eight months after planting

Cooktown-Lakeland RoadStabilisation of steep batters aboveculvert inlets and outlets

Steep batter protected by vetiver hedges

Eight months after planting

COSTS SUMMARYandCONCLUSIONNevil Bracken, Project Engineer,Pavement Construction Management Pty. Ltd

Road Batter ProtectionC ost SummariesAUD Per linearmetreAUD Per squaremetre of batterfaceVetiver hedges on CutBattersVetiver hedges on FillBatters18.40 21.4015.50 18.20Culvert ProtectionVetiver hedges 18.20Grouted rock pitching 65.75Saving 73%Road Shoulder ProtectionVetiver hedges 15.50T raditional concrete sh oulderdykes 38.00Saving 60%Table Drain Scour ProtectionVetiver contour hedges 15.50Traditional hard rock check dams 42.00Saving 64%Miscellaneous Protection W orkVetiver hedges generally 15.50Steel wire rock mattress 43.00Saving 64%

Other projects in Queensland- Blackwater-Emerald Railway Line- Murphy Creek – Toowoomba Railway line

Blackwater-Emerald Railway Line Unprotected batter

Two years after planting

Murphy Creek – Toowoomba Railway linePlanting on a steep batter

Once the batter fully stabilised after 6 years, native plantreturned to provide more permanent protectionVetiver row after slashing

OVERSEASEl Salvadore

A very high and steep road batter

Infrastructure ProtectionSome examples of works in Qld and Overseas• Dam walls

Nabalco Alumina Refinery, Gove, Northern Territorywall repaired after cyclone damageDam

Six weeks after planting

Two and half years after planting and unaffected by the wet season

Guangdong, China

South Africa

Infrastructure ProtectionSome examples of works in Qld and Overseas• River and stream bank erosion control

Principles of the Vetiver System for RiverBank StabilisationIn flood erosion control and riverbank stabilisation the VSuses the deep and high tensile root system to reinforce thebank slopes and its dense and stiff stems to spread andreduce flow velocity.• To stabilise the bank steep gradients, horizontal rows planted onapproximate contour lines• To reduce flow velocity of the strong current therefore preventingscouring from the strong flow, planting of cross rows is needed.• For maximum effect, the cross rows are orientated at right angleto the flow direction.• The spacing of both horizontal and cross rows varies with slopegradient and length, soil type, flow velocity and depth.

Condamine Highway between Miles and Goondiwindi

Severe erosion on the abutment of the Coolumboola Creek bridgenear Miles.

One month after planting

18 months after planting, note the bare area between rows, due tothe dry weather

Disaster Mitigation Project with Kellog Brown & Rootsat Quang Ngai, Vietnam

300 cumecs100cumecsVetiver rowsFlood erosioncontrol in drainagechannel at LaidleyVetiver hedges wereestablished to spreadwater out and also todivert water to the drainDrainage Channel

Water enters the site from the top and sideFlow

Middle section, note that vetiver hedges bent under strong current

Very fast flow flattened and inundated most of the hedges.The velocity was estimated up to 5m/sec in some areas

Submerged VetiverhedgesDrainage channel

Although only 3 month old, the young hedges provide a very effectiveprotection with only minimal erosion at the head of the channelSmall erosion

Strong flow exposed part of the crowns but failed todislodge the plants

Lake Evergreen, Guangdong, China:Highly erodible and badly eroded by wave during the wet season.

Two years after planting, trimming during the dry seasonWater line