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VETIVER GRASS SYSTEMVETIVER GRASS SYSTEM FOR INFRASTUCTURE
Dr. Paul TruongVeticon Consulting
www.uqconnect.net/veticon
All materials in this document remain the property of Veticon Consulting Pty Ltd. Permission must be obtained for their use. Copyright © 2010
Th V ti S t (VS) i b d th f ti (V ti i
INTRODUCTION• The Vetiver System (VS) is based on the use of vetiver grass (Vetiveria zizanioides L.) for a wide range of applications.
• VS was first developed by the World Bank for soil and water• VS was first developed by the World Bank for soil and waterconservation and now being used in over 100 countries. In Queensland VS was developed by the Department of Natural Resources for soil erosion and sediment control, land stabilisation and effluent disposal.erosion and sediment control, land stabilisation and effluent disposal.
• Vetiver grass is a native of the Indian sub-continent which was introduced to Queensland from Fiji since early in the 1900s. A sterile j ycultivar was selected and registered to the DPI as Monto vetiver in Queensland. Monto vetiver is sterile, non invasive, it flowers but set no seeds hence no weed potential.
• R&D conducted by DPI and DNR showed that Monto vetiver is tolerant to the most adverse conditions, high levels of pesticides and herbicides and also to a ide range of hea metal to icities Therefore VS hasand also to a wide range of heavy metal toxicities. Therefore VS has been successfully used for environmental protection purposes in Australia, Asia, Africa and Europe.
TOPICS OF TODAY PRESENTATION
1- Introducing Vetiver Grassg• Its extraordinary attributes
2- Infrastructure Protection• Road and Highway batters• Dam walls• River and stream bank erosion control
Introducing Vetiver grass
UNIQUE MORPHOLOGICALUNIQUE MORPHOLOGICAL CHARACTERISTICS OF
MONTO VETIVERMONTO VETIVER
S iff d h hStiff and erect shoot growth
Erect stems up
to 2m tall and over 2.5m with flower headflower head
Forming a thick hedge when planted in row
Strong current flattened the native grass but not vetiver on this waterway
Introducing Vetiver grass
UNIQUE MORPHOLOGICAL CHARACTERISTICS OF
MONTO VETIVER
Massive deep and penetratingMassive, deep and penetrating root system
China: One year old with 3.3m deep root system
A t li Oy
(These roots have a tensile strength equivalent to 1/6 mild steel reinforcement)
Australia: One year old, 1.3m and root bound
Infrastructure Protection
• Research on tensile and shear strength of the root gsystem• Road and Highway batters• Dam walls• River and stream bank erosion control
Soil stabilisation mechanism by vetiver
Vetiver hedgerows
V ti
slipping zone on slopes
Vetiver roots
slipping zone on slopes
usually 0~2 m depths
Diti Hengchaovanich
Shear test of vetiver roots
(These roots have a tensile strength equivalent to 1/6 mild steel reinforcement)
Strong root reinforcement holding up this wall of soil against water erosion
E iRoots
Extensive root distribution at depth of this am pwall
Infrastructure Protection
Some examples of works in Qld and Overseasp
• Road and Highway batters
Teemburra Dam Access Road Mackay Trial conducted by the Dept Environment and Heritage
After 400mm of rain in 10 days
One and half year after planting
Lakeland – Laura Road(At Split Rock )
Batter StabilisationBatter Stabilisation
CAPE YORK PENINSULARLakeland – Laura Road(At Split Rock )(At Split Rock )Severe erosion on unprotected cut slope
This concrete shute will collapse due to severe erosion and undermining.
Highly erodible cut batter prior to vetiver planting
Completely stabilised seven months after planting
Hydromulching seven months after planting
Cooktown-Lakeland Road
Stabilisation of road battersStabilisation of road batters
Batter protected by vetiver contour planting at between 0.5 and 1.0m Vertical Interval, Three weeks after planting
Eight months after planting
Cooktown-Lakeland Road
Stabilisation of steep batters above culvert inlets and outlets
Steep batter protected by vetiver hedges
Eight months after planting
COSTS SUMMARYCOSTS SUMMARYand
CONCLUSION
Nevil Bracken, Project Engineer,Pavement Construction Management Pty. Ltd
C o s t S um m a r ie sR o a d B a t te r P r o t e c t io n A U D P e r lin e a r
m e t r eA U D P e r s q u a r em e t re o f b a t t e r
f a c e
V e tiv e r h e d g e s o n C u tB a tte rs
1 8 .4 0 2 1 .4 0
V e t iv e r h e d g e s o n F illB a tte rs
1 5 .5 0 1 8 .2 0B a tte rs
C u lv e r t P r o t e c t io nV e tiv e r h e d g e s 1 8 .2 0G ro u te d r o c k p itc h in g 6 5 .7 5p g
S a v in g 7 3%
R o a d S h o u ld e r P r o te c t io nV e tiv e r h e d g e s 1 5 .5 0T d it i l t h ldT ra d it io n a l c o n c re te s h o u ld e rd y k e s 3 8 .0 0
S a v in g 6 0%
T a b le D ra in S c o u r P r o te c t io nT a b le D ra in S c o u r P r o te c t io nV e tiv e r c o n to u r h e d g e s 1 5 .5 0T ra d it io n a l h a rd r o c k c h e c k d a m s 4 2 .0 0
S a v in g 6 4%
M is c e lla n e o u s P r o t e c t io n W o rkV e tiv e r h e d g e s g e n e ra lly 1 5 .5 0S te e l w ire ro c k m a ttre s s 4 3 .0 0
S a v in g 6 4%
O j i QOther 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 plant returned to provide more permanent protection
Vetiver row after slashingVetiver row after slashing
OVERSEAS
El Salvadore
A very high and steep road batter
Infrastructure Protection
Some examples of works in Qld and Overseasp
• Dam walls
Nabalco Alumina Refinery, Gove, Northern Territory Dam wall repaired after cyclone damage
Six weeks after planting
Two and half years after planting and unaffected by the wet season
Guangdong, China
South Africa
Infrastructure Protection
Some examples of works in Qld and Overseasp
• River and stream bank erosion control
Principles of the Vetiver System for River Bank Stabilisation
In flood erosion control and riverbank stabilisation the VS uses the deep and high tensile root system to reinforce the bank slopes and its dense and stiff stems to spread and reduce flow velocity.
T t bili th b k t di t h i t l l t d• To stabilise the bank steep gradients, horizontal rows planted on approximate contour lines
• To reduce flow velocity of the strong current therefore preventingTo 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 angle to the flow direction.
• The spacing of both horizontal and cross rows varies with slope gradient and length soil type flow velocity and depthgradient and length, soil type, flow velocity and depth.
Condamine Highway between Miles and Goondiwindi
Severe erosion on the abutment of the Coolumboola Creek bridge near Miles.
One month after planting
18 months after planting, note the bare area between rows, due to the dry weather
Disaster Mitigation Project with Kellog Brown & Roots at Quang Ngai, Vietnam
Flood erosion control in drainage
300 cumecsVetiver rows
gchannel at Laidley
100 cumecs Vetiver hedges were cumecs
established to spread water out and also to divert water to the draindivert water to the drain
Drainage Channel
Water enters the site from the top and side
Flow
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 Vetiver hedges
Drainage channelg
Although only 3 month old, the young hedges provide a very effective protection with only minimal erosion at the head of the channel
Small erosion
Strong flow exposed part of the crowns but failed to dislodge 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 season
Water line
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