STABILISATION AND REHABILITATION OF STEEP SLOPES USING VETIVER SYSTEM TECHNOLOGY

Transcription

1 STABILISATION AND REHABILITATION OF STEEP SLOPES USING VETIVER SYSTEM TECHNOLOGY Paul Truong TVNI Technical Director, Brisbane, Australia All materials in this document remain the property of TVNI. Permission must be obtained for their use. Copyright /14/17 THE VETIVER NETWORK INTERNATIONAL 1

2 Vetiver System The Vetiver System (VS), which is based on the application of Vetiver grass ( Chrysopogon zizanioides L.), was first developed by the World Bank for soil and water conservation in India in the 1980s. In addition to its very important application in agricultural lands, scientific research conducted in the last 30 years has clearly demonstrated that VS is also one of the most effective and low cost natural methods of environmental protection. 12/14/17 THE VETIVER NETWORK INTERNATIONAL 2

3 VETIVER BIOENGINEERING A technology based on the use of vetiver grass The following characteristics make vetiver grass highly effective for steep slope stabilization: A deep, penetrating and extensive root system that binds the soil, and reinforces the soil structure which requires extraordinary force to dislodge. Erect and stiff stems forming a dense hedge which is very effective in retarding water flow and reducing the erosive power of the strong current. Vetiver is tolerant to drought, saline, sodic and acidic soil conditions. 12/14/17 THE VETIVER NETWORK INTERNATIONAL 3

4 These vetiver roots have a tensile strength equivalent to 1/6 mild steel reinforcement Vietnam China Thailand: 1 year 3.3m 12/14/17 THE VETIVER NETWORK INTERNATIONAL 4

5 Indonesian Institute of Road Engineering (IRE) Trial comparing 3 Vetiver planting densities, Bahia grass and bare slope at Nagreg, West Java 12/14/17 THE VETIVER NETWORK INTERNATIONAL 5

6 Bahia grass Vetiver Vetiver planted at 3 densities 12/14/17 THE VETIVER NETWORK INTERNATIONAL 6

7 Very steep, 80 0 slope on highly erodible red volcanic soil 12/14/17 THE VETIVER NETWORK INTERNATIONAL 7

8 Based on the above technical data, vetiver system has been used very effectively in stabilising extreme and highly erodible slopes around the world CHINA : Zhejiang Province (Cheng Zhou ) National Highway 330 on slope area of m2 to prevent landslides 12/14/17 THE VETIVER NETWORK INTERNATIONAL 8

9 BRAZIL : Road Batters (Paula Pereira, Deflor ) 12/14/17 THE VETIVER NETWORK INTERNATIONAL 9

10 BRAZIL : Road Batters (Paula Pereira, Deflor ) 12/14/17 THE VETIVER NETWORK INTERNATIONAL 10

11 INDONESIA : East Java ( IRE, ) : Before month 2.5 months Slope length 300m, height: 14 m, 4 months Regular trimmings after 4 month 12/14/17 THE VETIVER NETWORK INTERNATIONAL 11

12 MADAGASCAR : Railway between Tananarive and Tamatave (Yoann Coppin) Vetiver were planted in August 2013, total 2.500m in length, with a spacing of 0.60m between the rows. 12/14/17 THE VETIVER NETWORK INTERNATIONAL 12

13 THAILAND: Central Highlands (Surapol Sanguankaeo) 12/14/17 THE VETIVER NETWORK INTERNATIONAL 13

14 VENEZUELA: Road Batters (Rafael Luque) 12/14/17 THE VETIVER NETWORK INTERNATIONAL 14

15 GUATEMALA : Batters on 72 degree slope using 3D geofabrics (Leonel Castro) 12/14/17 THE VETIVER NETWORK INTERNATIONAL 15

16 Batters on 72 degree slope using 3D geofabrics (Leonel Castro) & Vetiver May 2012 December /14/17 THE VETIVER NETWORK INTERNATIONAL 16

17 DR CONGO: Road Batters (Roley Noffke ) On vertical slope using Green TerraMesh walls at Selembao Kinshasa and Vetiver. 12/14/17 THE VETIVER NETWORK INTERNATIONAL 17

18 The Ho Chi Minh Highway, Vietnam Following the failure of the costly conventional measure in controlling the erosion and landslips along the Highway, the Ministry of Transport adopted VST as a preferred erosion control measure on all new sections of the Highway and on eroded slopes of the completed sections. One to two month old planting on newly constructed batters 12/14/17 THE VETIVER NETWORK INTERNATIONAL 18

19 2005 SOME BEFORE AND AFTER VIEWS Vetiver Native plants and Vetiver 12/14/17 THE VETIVER NETWORK INTERNATIONAL 19

20 SOME BEFORE AND AFTER SCENERY Some vetiver left but mostly endemic plants /14/17 THE VETIVER NETWORK INTERNATIONAL 20

21 Gizo Island, Solomon Island, 2015 The application of VS to this site was under the technical support of Robinson Vanoh 12/14/17 THE VETIVER NETWORK INTERNATIONAL 21

22 Unstable, eroding site 12/14/17 THE VETIVER NETWORK INTERNATIONAL 22

23 Slope slippage with damage to building 12/14/17 THE VETIVER NETWORK INTERNATIONAL 23

24 Approx 45 o 1:1 12/14/17 THE VETIVER NETWORK INTERNATIONAL 24

25 Planting in /14/17 THE VETIVER NETWORK INTERNATIONAL 25

26 Two years after planting, /14/17 THE VETIVER NETWORK INTERNATIONAL 26

27 Two years after planting, /14/17 THE VETIVER NETWORK INTERNATIONAL 27

28 Two years after planting, /14/17 THE VETIVER NETWORK INTERNATIONAL 28

29 With Vetiver No Vetiver 12/14/17 THE VETIVER NETWORK INTERNATIONAL 29