Vegetative Stabilization Techniques for Slope Protection
and Erosion Control
Vegetative stabilization involves using living plant materials to protect, stabilize, and
reinforce slopes, embankments, gullies, and other erosion-prone areas. Below are key
techniques, their descriptions, site requirements, materials, procedures, advantages,
limitations, and maintenance practices.
1. Turfing
Definition:
Turfing is the direct application of grass with developed roots (turf) onto slope surfaces.
Mature grass grows easily and extends roots that strengthen and armor the slope.
Site Requirements:
Suitable for gentle slopes, less than 30°.
Pegging with wooden pegs (3 cm diameter, 30 cm long) is required for slopes
steeper than 25°.
Best suited for well-drained sites with minimal slumping.
Materials:
Sharp-edged shovel (for cutting turf)
Old Khukuri (to shape turf)
Water (to keep turf moist before planting)
Wooden rammer (for soil compaction)
Wooden pegs (for steeper slopes >25°)
Species: Dubo grass
Procedure:
1. Mark lines for turf size.
2. Cut turf in sizes 30×30 cm (easier) or preferred 30×60 cm to 5 cm depth.
3. Water hard ground one day before cutting turf.
4. Prepare site by removing irregularities or filling.
5. For gravel slopes, place and compact 5 cm of topsoil.
6. Scarify surface before placing turf.
7. Lay turf tightly without gaps.
8. Install turf on the same day as it is prepared.
9. Compact with wooden rammer and water thoroughly.
Function:
Protects topsoil from erosion; suitable for new or backfill slopes and embankments.
Disadvantages:
Causes bare patches at turf source due to cutting.
Discontinuity may lead to soil creep or shallow slope failure.
Vulnerable to grazing and trampling.
Costly compared to other methods.
2. Live Fascines (Willow Wattling)
Definition:
Bundles of live woody branches placed in shallow trenches along contour or diagonal
lines to catch debris, reduce runoff velocity, and reinforce the slope.
Function:
Creates step-like features on slopes, reduces surface erosion, and can act as slope
drainage if angled.
Site Suitability:
Slopes up to 45°, pegging required for slopes over 25°.
Materials:
Woody cuttings (1 m length, 20–40 mm diameter)
Tools for trench digging (15–20 cm deep and wide)
String or wire for binding (optional)
Hessian and water to keep cuttings moist
Species: Assuro, Simali, Dabdabe, Bainsh
Spacing:
For slopes <30°: 4 m apart
For slopes 30–45°: 2 m apart
Procedure:
1. Clear debris and irregularities.
2. Mark planting lines along contour.
3. Start from the bottom of the slope.
4. Dig trenches 20×20 cm, 5 m length at a time.
5. Place 4–8 cuttings per bundle with overlapping ends.
6. Bind bundles if necessary.
7. Backfill soil and compact around the bundles.
Advantages:
Effective on steep and rocky slopes.
Reduces erosion.
Low cost and maintenance.
Limitations:
High runoff may undermine fascines.
Large quantity of live material required.
Must be installed quickly to avoid drying. Requires moisture for survival.
Maintenance:
Protection (Kartik 1)
Weeding (Shrawan 1, Bhadra 1, Ashwin 1)
Thinning after 3 years (Kartik 1)
3. Brush Layering
Definition:
Placement of live woody branch cuttings in small terraces excavated along contour lines.
This divides the slope into shorter, reinforced segments, preventing erosion and
increasing stability.
Function:
Reinforces soil as roots grow.
Increases resistance to shear displacement.
Prevents rill and gully formation.
Improves shallow slope stability.
Difference from Live Fascines:
Cuttings are placed perpendicular (brush layering) vs. parallel (fascines) to the slope,
providing better soil reinforcement.
Site Requirements:
Slopes up to 45°, suitable for debris sites, fills, and high embankments. Toe protection
necessary.
Materials:
6–18 months old woody cuttings (2–4 cm diameter, 40–60 cm length)
String line, shovels, pickaxes, tape measure
Hessian and water for moisture
Forest topsoil (1 m³ per 20 m for gravel slope)
Species: Assuro, Phaledo, Simali, Nigalo, Bainsh, Dabdabe
Spacing:
<30° slope: 2 m between rows
30–45°: 1 m between rows
Between cuttings: 5 cm
Procedure:
1. Mark terrace lines starting 50 cm above slope base.
2. Work from bottom to top excavating terraces.
3. Allow about ¼ of each branch to protrude.
4. For gravel slopes, add 5 cm soil cushion before planting.
5. Lay branches with tips facing outward.
6. Add 2 cm soil cushion between layers.
7. Place a staggered second layer, then 8 cm soil for gravel sites.
8. Partially backfill with 5 cm soil, compact gently.
9. Repeat upslope.
Advantages:
Low cost, very effective reinforcement barrier.
Drains slope while supporting soil infiltration.
Useful on embankments and fill sites.
Limitations:
Labour-intensive construction.
Causes disturbance during installation.
Not suitable for poorly drained slopes.
Maintenance:
Protection (Kartik 1)
Weeding (Shrawan 1, Bhadra 1, Ashwin 1)
Thinning (Kartik 1, after 3 years)
4. Palisades / Live Staking
Definition:
Woody cuttings planted in rows along contour lines that act as soil barriers and create
small terraces.
Functions:
Roots bind soil and reduce moisture.
Stabilizes slope soil.
Site Requirements:
Suitable for slopes up to 60°.
Not as structurally strong as brush layering.
Materials:
Woody cuttings (12 mm diameter, 30–50 cm long)
Pointed planting bars or crowbars
Hessian, water
Species: Assuro, Phaledo, Simali, Bainsh, Dabdabe
Spacing:
<30°: 2 m between rows
30–60°: 1 m between rows
Between cuttings: 3–5 cm
Burial depth: 2/3 to 3/4 of cutting length (approx. 10 cm exposed)
Procedure:
1. Clear site and debris.
2. Mark contour lines.
3. Work top to bottom.
4. Dig holes deep enough for cuttings.
5. Insert cuttings with 10 cm above ground.
6. Cushion blows to avoid splitting.
7. Firm soil around cuttings.
Advantages:
Simple, low cost.
Effective up to 60° slopes.
Limitations:
Less structural strength than brush layering.
Maintenance:
Protection (Kartik 1), Weeding (Shrawan 1, Bhadra 1, Ashwin 1)
Thinning (Kartik 1 after 3 years)
5. Live Check Dams
Definition:
Woody cuttings planted across gullies to form barriers that slow water flow, trap
sediment, and encourage step-terrace development.
Functions:
Stabilizes gullies.
Increases infiltration and vegetation growth.
Protects gully floors.
Site Requirements:
Gully slope ≤45°
Side slope and floor modifications needed.
Ensure safe drainage disposal.
Materials:
Vertical hardwood cuttings (up to 2 m), spaced 1–1.5 m
Horizontal cuttings spaced 3–5 cm within dam
Crowbars, Hessian, water
Horizontal species: Assuro, Bainsh, Nigalo, Namdiphul
Vertical species: Dabdabe, Phaledo
Spacing Between Dams: 3–5 m, depending on slope and gully severity
Procedure:
1. Select gully sites.
2. Dig holes and plant vertical cuttings with 30 cm protruding.
3. Firm soil around vertical cuttings.
4. Place horizontal cuttings keyed into gully walls every 300–500 mm.
5. Backfill and compact soil.
Advantages:
Reduces water velocity.
Traps sediment and debris.
Encourages formation of terraces.
6. Hydro-Seeding
Definition:
Spraying a slurry of seed, mulch, and fertilizer onto soil surfaces to quickly establish
vegetation cover.
Functions:
Provides temporary surface protection.
Promotes seed germination and soil armoring.
Applicable Sites: Almost any, except poorly drained slopes.
Procedure:
1. Prepare site by removing debris and irregularities.
2. Mix slurry of seed, mulch, fertilizer.
3. Spray over slope evenly.
4. Maintain surface cover thickness of 5–20 mm.
Advantages:
Rapid coverage.
Increases organic matter and soil microbial activity.
Limitations:
Temporary solution; no structural reinforcement.
Costly.
7. Bamboo Culm Cuttings Plantation
Definition:
Planting rooted bamboo cuttings at the base of slopes and gullies to stabilize soil.
Site Requirements:
Cool, moist, non-stony sites.
Slopes ≤30°.
Spacing:
Across slope: 2 m
Up/down slope: 5 m
Materials:
Rooted single-node bamboo culm cuttings
Tools for hole digging
Hessian and water to keep roots moist
Mulch material
Species: Choya/Tama Bans, Dhanu Bans, Kalo Bans
Procedure:
1. Remove debris.
2. Wrap roots in wet hessian.
3. Dig holes and insert cuttings carefully.
4. Backfill and firm soil.
5. Apply mulch.
6. Create water-collecting depression around plants.
Advantages:
Provides strong base support.
Traps debris downslope.
Limitations:
Slow to stabilize (about 5 years).
Needs early protection from damage.
Upper steep slopes prone to slumping.
Maintenance:
Protection (Kartik 1)
Weekly watering during initial months (Chaitra, Baisakh, Jestha)
Mulching for 2 years (Mangsir 1)
