Catchment Fall — How To Verify Finished Surface

Design - Measure - Move - Verify

Design, measure, move and verify is a closed loop. The verification step tests whether the movement achieved the design rather than merely whether the operator followed a display.

Before moving material

Issue an agreed surface design and reliable control.

Receiving operation and checks

Correct residual defects and record acceptance before the next operation. Use independent observations for the final check.

Do not treat production guidance and acceptance evidence as the same record.

Survey & Verify

Survey and verification compares the delivered surface with the brief before it is covered by the next layer. It should establish both compliant areas and defects.

Before moving material

Agree the acceptance method and reference.

Receiving operation and checks

Record accepted work and required corrections. Check the issued design revision and datum used for comparison.

A level survey cannot prove compaction, and a density test cannot prove grade.

Incorrect Fall

Fall is the change in elevation along a defined direction. An incorrect fall can include a reversal, an insufficient gradient or a gradient that differs from the design.

Before moving material

Identify the start and end points, distance and elevation reference.

Receiving operation and checks

Measure the corrected profile independently. Check intermediate points because correct end levels can still hide a local dip.

There is no universal drainage fall appropriate to every project.

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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