Vetiver NIDM South Aug22 2019 x264

BIO-ENGINEERING MEASURES  BY VETIVER SYSTEM

Background

Growing of Vetiver hedges on contours and adopting conservation tillage practices between them has been proved to be an effective method to reduce runoff and soil loss, and increase in-situ moisture, thereby obtaining higher crop yields. The species of Vetiver System (Chrysopogon zizanioides), originates in the state of Tamil Nadu, South India, which is now being promoted in nearly 120 countries. It is sterile, non invasive and has to be propagated by clump subdivision. Generally nursery multiplication of bare rooted plants is the preferred method. The average multiplication rate varies but is normally, in a nursery, about 1:30 after about three months. The Vetiver System (VS) can reduce or even eliminate landslides, mudslides, road batter instability, and erosion (river banks, canals, coastlines, dikes, and earth-dam batters). 

More than half of India's cropland is losing productivity because topsoil is being washed or blown away faster than natural forces can replace it. Reducing the topsoil layer means reducing plants' access to essential soil nutrients and water. For at least the next decade environmental issues will dominate the agricultural and natural resource sectors. Already the focus of much attention are the problems of deforestation, increased flooding by major rivers, and reduced dry-season water flows for irrigation and urban and industrial supplies. Not enough attention, however, has been given to the massive problem of soil erosion and, more specifically, to the need to reduce soil and water losses caused by excessive rainfall runoff. Changes in farming practices have made the problem worse in recent years. In response to the growing need for grain for exploding human and livestock populations, farmers switched from traditional rotations and multiple cropping to continuous-row cropping, a practice that encourages rainwater to run off the land at a faster and more destructive pace. As a result crops are denied the moisture they need for optimum growth (Truong and baker, 1998).

Results of numerous trial and mass applications of Vetiver grass in the last 30 years in many countries show that the grass is particularly effective in natural disaster reduction (flood, landslide, road batter failure, river bank, irrigation canal and coastal erosion, water retaining structure instability etc.), environmental protection (reduction of land and water contamination, treatment of solid and liquid waste, soil improvement etc.), and many other uses. The species of Vetiver System originates in the state of Tamil Nadu, South India, which is now being promoted in nearly 120 countries. It is a perennial bunchgrass of the Poaceae family. In western and northern India, it is popularly known as Khus. It is sterile, non invasive and has to be propagated by clump subdivision. Generally nursery multiplication of bare rooted plants is the preferred method. The average multiplication rate varies but is normally, in a nursery, about 1:30 after about three months. Nursery clumps are divided into planting slips of about 3 tillers each, and typically planted 15 cm apart on the contour to create, when mature, a barrier of stiff grass that acts as a buffer and spreader of down slope water flow, and a filter to sediment. A good hedge will reduce rainfall run off by as much as 70% and sediment by as much as 90%. A hedgerow will stay where it is planted and the sediment that is spread out behind the hedgerow gradually accumulates to form a long lasting terrace with Vetiver protection. It is a very low cost, labour intensive technology (linked to the cost of labour) with very high benefit: cost ratios. When used for civil works protection its cost is about 1/20 of traditional engineered systems and designs. Engineers liken the Vetiver root to a "Living Soil Nail" with an average tensile strength of 1/6 of mild steel.

What is Vetiver?

Vetiver is most closely related to Sorghum but shares many morphological characteristics with other fragrant grasses, such as lemongrass (Cymbopogon Citratus), citronella (Cymbopogon Nardus, C. Winterianus), and Palmarosa (Cymbopogon Martinii). It is a tall, tufted, perennial, scented grass, with a straight stem, long narrow leaves and a lacework root system (Fig. 1) that is abundant, complex, and extensive. It offers an inexpensive yet effective and eco-friendly tool to combat soil erosion. The roots have been used in Asia for centuries for their fragrance, and are woven into aromatic matting and screens. The roots of some cultivars and ecotypes possess essential oil that has been utilized as fragrant material since ancient times. The plant also contains active ingredients used in traditional medicine and as botanical pesticide.

The Plant Vetiver belongs to the same group of grass family of rice, maize, sorghum, sugarcane and lemon grass. It got its generic name Vetiveria, from its Tamil name 'Vetiver' which means root that is dug up. Its specific epithet, Zizanioides means 'the river side'. The fact is that the plant is commonly found along the waterways. Its name was later reclassified as Chrysopogon zizanioides. There are two types of Vetiver; one is seedling and the other is non seedling. Seedling type is commonly found in North India, where as non seedling variety is common in South India. Only the non seedling variety can be recommended for any purpose connected with Vetiver, because the other variety is able to spread unwantedly through seeds. The South Indian variety of Vetiver has existed for centuries under cultivation and is widely distributed throughout the continents. This variety can be propagated only through vegetative method.

SPECIAL CHARACTERISTICS OF VETIVER GRASS

Morphological characteristics:

•         Vetiver grass does not have stolons or rhizomes. Its massive finely structured root system that can grow very fast, in some applications rooting depth can reach 3-4m in the first year. This deep root system makes vetiver plant extremely drought tolerant and difficult to dislodge by strong current.

•         Stiff and erect stems, which can stand up to relatively deep water flow

•         Highly resistance to pests, diseases and fire

•         A dense hedge is formed when planted close together acting as a very effective sediment filter and water spreader.

•         New shoots develop from the underground crown making vetiver resistant to fire, frosts, traffic and heavy grazing pressure.

•         New roots grow from nodes when buried by trapped sediment. Vetiver will continue to grow up with the deposited silt eventually forming terraces, if trapped sediment is not removed.

Fig. 1: Multi-functioning and multi-dimensional Vetiver system for the complete remediation of bio-environment

Physiological characteristics

•         Tolerance to extreme climatic variation such as prolonged drought, flood, submergence and extreme temperature from -15ºC to +55ºC. The optimal soil temperature for root growth is 25 °C. Root dormancy occurs under a temperature of 5 °C. Shoot growth is affected earlier; at 13 °C, shoot growth is minimal, but root growth is continued at a rate of 12.6 cm/day. Under frosty conditions, shoots become dormant and purple, or even die, but the underground growing points survive and can regrow quickly if the conditions improve.

•         Ability to regrow very quickly after being affected by drought, frosts, salinity and adverse conditions after the weather improves or soil ameliorants added.

•         Tolerance to wide range of soil pH from 3.5 to 11.0 without soil amendment.

•         High level of tolerance to herbicides and pesticides.

•         Highly efficient in absorbing dissolved nutrients such as N and P and heavy metals in polluted water.

•         Highly tolerant to growing medium high in acidity, alkalinity, salinity, sodicity and magnesium.

•         Highly tolerant to Al, Mn and heavy metals such as As, Cd, Cr, Ni, Pb, Hg, Se and Zn in the soils

•         Vetiver’s extremely deep and massive finely structured root system can extend down to two to three meters in the first year. On fill slope, many experiments show that this grass can reach 3.6m in 12 months. Vetiver does not penetrate deeply into the groundwater table. Therefore, at sites with a high groundwater level, its root system may not extend as long as in drier soil.

•         Vetiver’s extensive, and thick root system binds the soil which makes it very difficult to dislodge, and extremely tolerant to drought.

•         Vetiver roots can penetrate a compacted soil profile such as hardpan and blocky clay pan common in tropical soils, providing a good anchor for fill and topsoil.

•         When planted closely together, Vetiver plants form dense hedges that reduce flow velocity, spread and divert runoff water, and create a very effective filter that controls erosion. The hedges slow down the flow and spreads it out, allowing more time for water to soak into the ground.

•         Acting as a very effective filter, Vetiver hedges help reduce the turbidity of surface run-off. Since new roots develop from nodes when buried by trapped sediment, Vetiver continues to rise with the new ground level. Terraces form at the face of the hedges, this sediment should never be removed. The fertile sediment typically contains seeds of local plants, which facilitates their re-establishment. (Truong et al, 1996).  

•         This grass re-grows very quickly following drought, frost, salt and other adverse soil conditions when the adverse effects are removed.

•         Vetiver displays a high level of tolerance to soil acidity, salinity, solidicity and acid sulphate conditions (Le van Du and Truong, 2003)

Erosion control by Vetiver

Vetiver planting has been very effective in erosion control or stabilisation in the following conditions:

•         Slope stabilisation along highways and railways. Especially effective along mountainous rural roads, where the community lacks sufficient funding for road slope stabilisation and where it often takes part in road construction.

•         Dike and dam batter stabilisation, reduction of canal, riverbank and coastal erosion, and protection of hard structures themselves (e.g. rock riprap, concrete retaining walls, gabions, etc.).

•         Slope above culvert inlets and outlets (culverts, abutments).

•         Interface between cement and rock structures and erodible soil surfaces.

•         As a filter strip to trap sediment at culvert inlets.

•         To reduce energy at culvert outlets.

•         To stabilize gully head erosion, when Vetiver hedges are planted on contour lines above gully heads.

•         To eliminate erosion caused by wave action, by planting a few rows of  Vetiver on the edge of the high water mark on big farm dam batters or river  banks.

•         In forest plantations, to stabilize the shoulders of access roads on very steep  slopes as well as the gullies (logging paths/ways) that develop following harvests.

Benefit of Vetiver Grass

§  A permanent, low maintenance solution: Vetiver grass is a perennial plant, which provides a permanent solution with little or no maintenance

§  Strong anchors are spread evenly over the stabilized area: The Vetiver root mass is very large and the fibrous roots are very strong

§  Deep anchorage: Vetiver roots penetrate several meters into native soil or fill material

§  A durable surface: Vetiver foliage is tough, it survives fire and extended flooding

§  Stops soil erosion: The dense foliage traps soil particles being washed downhill

§  Improves water quality: Sediments are trapped by foliage before entering nearby waterways

§  Water harvesting, flood mitigation: Vetiver greatly increases percolation rates

§  Supports local economies: Vetiver projects are labor intensive. They employ locals, especially in rural areas

§  A ‘Green’ solution: Vetiver is more natural and more attractive than stone or concrete

§  Side-benefits: Vetiver foliage may be harvested for thatching, fodder, composting or other purposes where biomass is required

Risk Assessment 

§  Vetiver is non-invasive: It sets sterile seed and does not have running stolons

§  Vetiver is non-competitive: Roots grow vertically downwards, vetiver does not compete with adjacent plants

§  Safe from pests and disease: Vetiver has been shown to have very few pest or disease problems

§  Precedents: Vetiver has been proven in many projects in many countries around the world. Vetiver has been promoted and supported by the World bank for many years

Advantages:

•         The major advantage of VS over conventional engineering measures is its low cost and longevity. For slope stabilisation in China, for example, savings are in the order of 85-90% (Xie, 1997 and Xia et al, 1999). In Australia, the cost advantage of VS over conventional engineering methods ranges from 64% to 72%, depending on the method used (Braken and Truong 2001). In summary, its maximum cost is only 30% of the cost of traditional measures. In addition annual maintenance costs are significantly reduced once Vetiver hedgerows are established

•         As with other bioengineering technologies, VS is a natural, environmentally-friendly way to control erosion control and stabilize land that ‘softens’ the harsh look of conventional rigid engineering measures such as concrete and rock structures. This is particularly important in urban and semi-rural areas where local communities decry the unsightly appearance of infrastructure development.

•         Long-term maintenance costs are low. In contrast to conventional engineering structures, green technology improves as the vegetative cover matures. VS requires a planned maintenance program in the first two years; however, once established, it is virtually maintenance-free. Therefore, the use of Vetiver is particularly well suited to remote areas where maintenance is costly and difficult.

•         Vetiver is very effective in poor and highly erodible and dispersible soils. 

VS is particularly well suited to areas with low-cost labour forces. Vetiver hedges are a natural, soft bioengineering technique, an eco-friendly alternative to rigid or hard structures.

Disadvantages:

•         The main disadvantage of VS applications is the Vetiver’s intolerance to shading, particularly within the establishment phase. Partial shading stunts its growth; significant shading can eliminate it in the long term by reducing its ability to compete with more shade-tolerant species. However, this weakness could be desirable in situations where initial stabilisation requires a pioneer to improve the ability of the micro-environment to host the voluntary or planned introduction of native endemic species.

•         The Vetiver System is effective only when the plants are well established. Effective planning requires an initial establishment period of about 2-3 months in warm weather and 4-6 months in cooler times. This delay can be accommodated by planting early, and in the dry season.

•         Vetiver hedges are fully effective only when plants form closed hedgerows. Gaps between clumps should be timely re-planted.

•         It is difficult to plant and water vegetation on very high or steep slopes.

•         Vetiver requires protection from livestock during its establishment phase.

Required Enforcement towards Earthquake Resistant Constructions

       i.            To ensure empowerment and accountability of the various actors involved in building construction, namely, the owner, the builder/developer/promoter, the architect, the structural engineer, supervisors, the local body personnel involved in approval of plans, inspection of constructions and issuing of building use permits.

     ii.            To insist on the submission of design and drawings signed by all four stakeholders namely, the owner, builder of approved qualifications, qualified architect and structural engineer of specified qualifications before the permit to build is issued.

  iii.            To insist on submission of a building schedule (check list) along with the application indicating the data and the standards that will be followed, to be cleared by one of the empanelled experts by the competent authority.

  iv.            Building use permit be issued only after complete structural design adopted, material test certificates and other safety certificates for fire and electrical installations etc. are submitted to the satisfaction of the local authority.

     v.            To formulate suitable legislative mechanisms for regulating the professional conduct (with penal provisions) and related responsibilities of architects, engineers (responsible for structural design and supervision) builders, developers and promoters.

  vi.            Efforts should be made to construct and maintain major hospitals, school buildings and public amenity building for storage of essential life saving materials (food, medicine), equipment and machinery for removal of damaged material, using disaster resistant technologies of a higher order, so that these buildings not only serve as good examples of disaster resistant technology but also could be utilised as relief shelters providing the necessary emergency support facilities.

vii.            Efforts for integrating seismic safety in construction practice of owner-built houses is considered a part of a comprehensive strategy that includes public awareness programs, regular consultation for house-owners, informal training to masons and contractors, and education and training programs at the community levels. Efforts must be made to build the capacity of local authorities (municipalities) in adopting seismic provision of building codes in their building permit process.

EXPLORING DISASTER PREPAREDNESS

By

Prof. Chandan Ghosh, NIDM

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In tackling Disasters

Let’s try our best possibly

In the quest of

Our Faithfulness to the GOD almighty   (? )

Our Knowledge, knowhow, supportive environs  (?) 

Resources, analytical power,  data-mining  (?)

Scientific, experimental, technical acumen   (?)

Rehearsing

Our Hard work, sincerity, skills, man power    (?)

Modeling, predicting, early warning tenacity  (?)

Ideology, budgetary support, attitudinal idiosyncrasy   (?)

Trying, befalling, deadline friendly cultural ethnicity (?)

Let’s look forward to

Nurturing

Our undeterred  outlook in managing and

Fortifying disaster response teams amid

Amending DM-Act and making effective DM system

That become operative in plans and reports

Dictating

Everything under the tutelage of relief managers

Who despite having trained to adapt IRS

Remain hapless until disaster events

Drive all into grave crises and panicky

Ordering

Thru’ emergent meeting to edifice crisis mongers

 In the proliferation of lot more punitive

Yet toothless regulating authorities made for

Exerting conditional blockages to seamless operations

Regulating

All developmental activities in the Himalaya

Charged by the oath for protecting environs that

Creating uncertain cloud bursts and flash flood

Uprooting our establishments by landslides

Creating

Enigmatic shadow in the name of enviro-degradation

To which EIA officials continue to play role

In the data-mining for the software input

Often tuned enough to satisfy distorted whims of few

Getting

Woefully busy in sanctioning man-made activities

In several counts under the run-of-the river projects

In some vested manners and spirit we continue to see

All formalities in files but for the sake of the Himalaya

Delegating 

Responsible organs to take on the complaints

Filed thru’ PILs and RTIs by some of the affected

Who run from pillar to post to fend their rights

And privilege to live peacefully adoring Himalaya

Expecting

Much of the share of the resources and energy

Tapped out of the multipurpose projects

Alluring pilgrimage for the sake of affluent living

In tune with all that enjoyed by those living in plains

Let’s unite for the cause

Voicing

Our concern to respond to every such clarion

Call from the Nature by re-jigging us from slumber

Ordering our organised forces to tackle situation

Much to the need of the victims on compassion

Ordering

Command and poring relief packets from the sky

Counting on the fortitude and courage shorn

By Army, NDRF and many faith based organisations

Mounting with figures and heating debates in the media

Orchestrating

Hi-flying teams often sans subject specialities

To oversee the damages and losses sans quantifying tools

Followed up by surveys and sanctioning budget

For the states suffering the blunt of the shaking

Follow up actions 

In the name of post-disaster need assessment

And submitting reports after organising disaster tourism

Thereafter, conducting seminar-symposium-talk-show

For the sake of awareness drive and seasoned life style

Nay!

By all might the country has achieved several milestones

In keeping our organized forces in perfect order

Making them effectively functional gratifying in

Coordinating response and relief operations

Despite

Tattered by misgivings of the communication

Network and unrealised early warning system

Unmindfully maintained by nodal agencies

Leave us at our fate unaware, uncalled for

Yet

We shall continue to unravel our lacunae

In the name of disaster preparedness

Till we come forward with all sincerity

While wrapping up the truth before

Taking ownership by anybody for the

Unbecoming of our resilience syndrome

While every event takes us a bit closer to

Revisit and have reality check on our preparedness! 

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