Category: management

(updated August 22, 2026)

This package is a suite of generic design standards and guides for Vetiver Grass Technology, grounded in research, long-term field experience and, where applicable, current engineering practice. It exists because the global spread of VGT created a need for consistency. The standards give practitioners design and implementation guidance, help agencies, consultants and contractors prepare contract-ready documentation, and set minimum technical requirements for design, plant material, installation and quality assurance.

They are deliberately generic. VGT is a nature-based technology, and local soils, climate, hydrology, effluent characteristics and regulation all shape how it performs. Adapt them to your site, your regulatory framework and your project objectives. Do not apply them rigidly.

Every module contains a table of contents and a reference list supporting its design logic. Links point to Google Drive; internal table-of-contents links work only once the file is downloaded.

Start here

Background reading — the science behind the standards

Choosing a module

Modules are grouped in four domains — A water and hydrological protection, B slopes, earthworks and geotechnical stability, C wastewater, effluent and pollution control, D livelihoods, products and community systems. Work from the problem, not the domain:

Many sites need more than one module. Common pairings: B1 + C5 for landfills; B1 + C2 for sewage lagoons; A6 + A5 for degraded catchments; A3 + A4 for hydropower reservoirs; any C module + D1 for community-run systems.

 Data to gather before you design

 What VGT can and cannot do

VGT can

• Increase near-surface shear strength and reduce shallow slip risk
• Increase infiltration in the hedge zone and reduce runoff volume and velocity
• Reduce pore-water pressure in the rooted layer
• Trap sediment and build terraces
• Treat wastewater through evapotranspiration and nutrient uptake
• Survive nearly indefinitely anaerobic conditions so long as not totally submerged and receives a transition period
• Stabilize slopes, banks, embankments and gully works
• Supply forage, mulch, improve soil structure and health, thatch and craft material, and support rural enterprise

VGT cannot

• Replace structural reinforcement where deep-seated failure is likely
• Treat effluent beyond the biological capacity of the system without pre-treatment
• Grow in deep shade (stops growing at 80% shade)
• Tolerate glyphosate

Common causes of failure

Across global experience, failures come from a short and repetitive list. Each module’s design envelope carries its own risk notes; these are the ones that recur everywhere.

• • • Glyphosate drift. It kills vetiver outright. Keep a 2 m no-spray corridor and settle this at design stage, not in year two. Decisive where VGT is proposed alongside herbicide-based conservation tillage.
  • • Shade. Deep shade suppresses growth severely. Note that shading an already-established hedge is more damaging than establishing under shade, so agroforestry and orchard designs must consider canopy closure years ahead.
  • • Abrupt transfer into saturated ground. Vetiver does grow in waterlogged anaerobic soil, but it takes roughly three weeks to build the aerenchyma that oxygenates its roots there. Dryland-raised material set straight into standing anaerobic mud is at risk through that window. Stage the transition, or use material already raised wet. This is an establishment constraint, not a species limit — and it is the likeliest origin of the belief that vetiver cannot take waterlogging.
  • • Incorrect spacing, density or alignment. Off-contour alignment destroys the spreading function, which is the mechanism most field results depend on.
  • • Poor maintenance in the first 8–12 weeks. Includes livestock access before the hedge is established, and cultivation too close to the line.
  • • Overloading evapotranspiration or treatment systems. Loading beyond design capacity.
  • • Planting on active landslide zones. Drainage control comes first.
  • Ignoring hydrological pathways. Especially seep lines.

The Modules

Note: The fifth column will link each module to a matching specification sheet — problem definition, performance objectives, design criteria, layout, materials, installation sequence, operation and maintenance, failure modes and monitoring indicators, with numeric fields left open. This turns each standard into something a client can put into a proposal and a contractor can bid against. It is the step that makes the package commercially usable, and it directly supports the policy argument above. The current modules in this column are all version 1 and require revision.

A — Water and hydrological protection

B — Slopes, earthworks and geotechnical stability

C — Wastewater, effluent and pollution control

D — Livelihoods, products and community systems

Keeping the package current

These standards will keep developing, because VGT is a living technology and innovation, field learning and practitioner experience remain essential to it. TVNI welcomes feedback, case studies, corrections and technical contributions. Where errors are identified, modules are revised and the package is reissued; new modules are added as they are completed. Contradicting field evidence is as welcome as corroborating evidence, and more useful.