Guidelines on Tree Plantation along Rural Roads

IRC SP 103 - Scope & Key Specifications for Avenue Plantations (Clause 4.7)

This clause defines technical specifications for roadside plantations along rural roads to ensure ecological and aesthetic benefits.

Key Specifications from Table 4:

Additional Notes:

• In alkaline soils, break kankar pans with augur.
• In waterlogged areas, create mounds with height based on water level.
• Plantations should be close to the edge of the ROW but at least 0.5 m from embankment toe.

Visual Summary:

flowchart LR
    A[Toe of Embankment]
    B[Ornamental Plants<br>0.5 m away]
    C[Shade Plants<br>3 m behind Ornamental]
    A --> B --> C

This ensures proper spacing, survival, and growth conditions for roadside plantations per IRC SP 103.

IRC SP 103: General Considerations for Avenue Plantations

Key Specifications (Clause 4.7, Table 4)

Additional Notes:

• Pits should be prepared carefully considering soil conditions.
• Survival rate is critical for sustainable plantation.
• Plantations must be close to the ROW edge but maintain minimum distance from embankment toe.

flowchart LR
    A[Toe of Embankment] -->|≥ 0.5 m| B[Ornamental Plants (1st Row)]
    B -->|≥ 3 m| C[Shade Plants (2nd Row)]
    B -->|4-6 m spacing| B
    C -->|8-12 m spacing| C

This ensures proper spacing, growth, and roadside safety as per IRC SP 103.

Selection of Tree Species – IRC SP 103 Key Points

1. Species Selection Criteria (Clause 4.2)

• Tree form & size (spread, shape)
• Foliage/flower/fruit texture & color (seasonal variation)
• Adaptability to agro-climatic zones
• Growth rate & maturity age
• Maintenance needs
• Economic/social benefits
• Drawbacks (pests, grazing, human interference)

2. Recommended Species (Appendix-II & Tables 1 & 2)

3. Plantation Specifications (Table 4, Clause 4.7)

flowchart TD
    A[Selection of Tree

IRC SP 103: Plantation Techniques and Layout (Clause 4.7)

Key Specifications for Avenue Plantations (Table 4)

Additional Notes

• Pit preparation: In alkaline soils, break kankar pans using an augur.
• Waterlogged areas: Create mounds with height based on water level.
• Survival: Replace casualties within first 2 years for shade plants to maintain 90% survival.

flowchart LR
    A[Toe of Embankment] -->|0.5 m| B[1st Row: Ornamental Plants]
    B -->|3 m| C[2nd Row: Shade Plants]
    B -->|4-6 m spacing| D[Plant to Plant]
    C -->|8-12 m spacing| E[Plant to Plant]

This layout ensures healthy growth, adequate spacing, and longevity of roadside plantations per IRC SP 103 standards.

Bio-Engineering Measures in Slope Stabilization (IRC SP 103 Highlights):

• Purpose: Complement civil engineering works to stabilize roadside slopes against erosion and improve drainage.
• Plant Functions:
  • Anchor and reinforce soil via deep roots.
  • Trap erodible material/debris.
  • Drain excess water from slopes.

Key Specifications:

• Bio-engineering does not replace structural measures but supplements them.
• Plant selection and methodology are critical for success.
• Materials and skills for bio-engineering are locally available in rural areas.
• Refer to MoRD Specifications for Rural Roads, Section 16 (Clause 1612), 2014 for detailed procedures.

Plant Management (Clause 4.12.2):

• Pruning promotes healthy growth, removes diseased parts, and regulates flowering.
• Use proper tools: pruning knives, saws, shears.
• Prune during dormancy (Dec-Jan & May-Jun).
• Avoid damaging bark; remove overcrowded or weak branches.
• Light pruning can be done anytime for safety or sanitation.

Typical Bio-Engineering Techniques:

flowchart LR
    A[Slope Stability] --> B[Structural Measures]
    A --> C[Bio-Engineering Measures]
    C --> D[Plant Root Anchoring]
    C --> E[Surface Protection by Vegetation]
    C --> F[Drainage Improvement]
    B --> G[Retaining Walls, Drainage]

Summary: Use bio-engineering as a complementary measure with proper plant selection, pruning, and maintenance to enhance slope stability and erosion control.

IRC SP 103: Bridges and Approaches - Key Points

Design & Aesthetics (Clause 6.1)

• Bridge structures including railings, parapet walls must enhance road and landscape aesthetics.
• Approaches should blend with terrain, preserving natural beauty.
• Align major bridge approaches for visibility, breaking travel monotony.
• Use adequate planting & landscaping near bridges for visual enhancement.

Bio-engineering Measures (Clause 5.1)

• Use living plants for slope stabilization and erosion control alongside civil engineering.
• Plants anchor soil, catch debris, and improve drainage.
• Selection of plant species and methods is crucial.
• Refer MoRD Specifications (Section 16, Clause 1612) for detailed bio-engineering guidelines.

Typical Cross-Section (Clause 5.5)

• For rural intermediate lane:
  • Carriageway width: 5.5 m
  • Formation width: 9.0 m
• Refer Fig. 2 in IRC SP 103 for cross-sectional details.

Summary Table: Typical Rural Bridge Formation Width

flowchart TD
    A[Bridge Structure] --> B[Railings & Parapets]
    A --> C[Approaches]
    C --> D[Blend with Terrain]
    C --> E[Visible Alignment]
    A --> F[Landscaping & Planting]
    F --> G[Slope Stabilization]
    G --> H[Bio-engineering + Civil Measures]

This ensures functional, aesthetic, and environmentally sensitive bridge and approach design per IRC SP 103.

Maintenance of Roadside Plantation (IRC SP 103)

Key Specifications (Table 4 - Avenue Plantations)

Maintenance Guidelines

• Ensure visibility at intersections by maintaining height limits and clear sight lines (Clause 6.2).
• Pit preparation: Break kankar pans in alkaline soils; mound soil in waterlogged areas to prevent waterlogging.
• Survival monitoring: Replace casualties within first two years to maintain ≥ 90% survival.
• Spacing and positioning to avoid root damage to embankments and ensure healthy growth.

flowchart LR
    A[Planting] --> B[Pit Preparation]
    B --> C[Planting Saplings]
    C --> D[Spacing & Positioning]
    D --> E[Regular Watering & Fertilizing]
    E --> F[Monitoring Survival]
    F --> G[Replacement of Casualties]
    G --> H[Maintaining Sight Lines at Intersections]

This ensures sustainable roadside greenery, safety, and road visibility.

IRC SP 103 — Special Areas and Environmental Considerations: Key Specifications for Avenue Plantations

Table 4: Technical Specifications for Plants

Environmental Considerations

• Plant species selection should consider local climate and soil (see Annex A-E for regional species).
• Bio-engineering for slope stabilization is recommended (Clause 5).
• Maintain minimum distances to avoid embankment damage and ensure safety.

Summary Diagram of Plantation Layout

graph LR
    A[Embankment Toe]
    B[Ornamental Plants]
    C[Shade Plants]
    A -->|≥0.5 m| B
    B -->|≥3 m| C
    B -->|4-6 m spacing| B2[Next Ornamental Plant]
    C -->|8-12 m spacing| C2[Next Shade Plant]

This ensures durability, aesthetic value, and environmental compatibility along rural roads per IRC SP 103.

IRC SP 103 - Specifications for Grass Turfing (Clause 4.9)

Key Specifications:

• Surface Preparation (4.9.1):

  • Remove loose debris.
  • Level surface: fill concavities, remove convexities.
  • Provide good quality soil layer up to 450 mm depth for grass growth.

• Grass Sowing (4.9.2):

  • Grass seed rate: 25 grams/m².
  • Sowing time: Before monsoon onset (May-June).
  • Watering: Use tankers until monsoon rains begin.
  • Mulching: Apply a thin layer of dried herbs mulch to reduce sunlight and moisture loss.

• Purpose:

  • Establish a strong surface cover resistant to erosion and mass movement during initial growth.

Summary Table for Grass Turfing

flowchart TD
    A[Surface Preparation] --> B[Remove debris, level surface]
    B --> C[Apply good soil layer (450 mm)]
    C --> D[Grass Sowing (25 g/m²)]
    D --> E[Watering till monsoon]
    E --> F[Mulching with dried herbs]
    F --> G[Establishment of erosion-resistant grass cover]

This ensures a durable, erosion-resistant turf on embankments as per IRC SP 103.

IRC SP 103 - Personnel of Highways Specifications and Standards Committee

The document lists the committee members responsible for highway specifications and standards as of August 2014. This includes:

• Convenor: Das, S.N. (Director General, MORTH)
• Co-Convenor: Varkeyachan, K.C. (Addl. Director General, MORTH)
• Member-Secretary: Chief Engineer (R) S,R&T (Rep. by Shri S.K. Nirmal)
• Members: Senior engineers, professors, and consultants from MORTH, CRRI, IITs, PWDs, NHAI, and private sector.
• Corresponding Members: Experts and retired officials contributing as needed.
• Ex-Officio Members: Key office bearers of the Indian Roads Congress.

Key Points:

• The committee includes experts from government, academia, and industry.
• Roles cover policy, research, design, and implementation aspects.
• No formulas or technical tables are associated with this section.

This list is primarily for reference and governance and does not contain design formulas or technical specifications.

graph TD
A[Convenor] --> B[Co-Convenor]
B --> C[Member-Secretary]
C --> D[Members]
D --> E[Corresponding Members]
E --> F[Ex-Officio Members]

For technical formulas and tables, refer to other clauses of IRC SP 103 or relevant IRC codes.

Key Details on Recommended Tree Species (IRC:SP:103-2014)

1. Categories of Tree Species

• Category 1: Single row (usually ornamental trees for rural roads)
• Category 2: Two rows (shade and screening trees)

2. Recommended Species

3. Plantation Specifications (Table 4)