Survey → Survey Verification — Drainage

Drainage Grade Design

Drainage grade design must connect the contributing area to a suitable outlet. Selecting a numerical fall before checking the outlet can produce a surface that cannot discharge as intended.

Before moving material

Survey entry points, structures and the receiving level.

Receiving operation and checks

Inspect the constructed route and its transitions. Check invert continuity and controls at crossings.

This guide does not size drains or establish discharge permissions.

What Verification Evidence Proves

Verification evidence should answer the acceptance question asked. Elevation measurements establish geometry; material records and relevant tests address layer condition. Neither should be silently substituted for the other.

Before moving material

Define the checks needed for the finished purpose.

Receiving operation and checks

Hand over accepted areas and clearly identify exceptions. Check that the evidence concerns the same layer and work zone.

An instrument display is not a complete acceptance record.

The Surface Is the Handover

The surface is the handover between operations. An excavator may finish its excavation, but the roller still needs suitable material, lift thickness and moisture. A scraper may finish shaping, but the irrigation operator still needs a connected fall to a usable outlet. Define acceptance at each transition instead of allowing the next machine to inherit an unresolved problem.

Before moving material

Name the operation that receives the surface and agree its requirements.

Receiving operation and checks

Release the area to the next operation only after outstanding defects are identified. Use independent level checks and project-specific material tests where required.

Visual smoothness alone does not prove compaction, bearing capacity or hydraulic performance.

Record the job inputs

Use this checklist to turn the scenario into a specific brief. Retain the design revision and agree who accepts each completed layer.

• Existing condition, extent and the reason for intervention
• Required finished purpose, receiving operation and acceptance criteria
• Material type, layer role, source, receiving area and volume state
• Reference levels, datum, survey method and issued design revision
• Available tractor, implement configuration, travel route and turning space
• Checks before work, stopping points and evidence retained at handover

Checklist ticks apply only while this page is open. Include the completed brief in your project records.

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