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