Contents

  • Cover
  • Front matter
  • Introduction
  • Identifying and managing risk
    • Risk overview
    • Working smart and efficiently
    • Starting the job – be prepared
    • The job is not finished until it is signed-off
  • Basics
    • Roading terms
    • Basics about soil
  • Good construction
    • A well-constructed road
    • A well-constructed landing
  • Earthworks
    • The right machine for the task
    • Clearing and stripping
    • Cut and side cast construction
    • Cut and bench fill construction
    • Full bench construction with end-haul
    • Earthworks compaction
    • Landing construction
    • Forming road corners and in-bends
    • Final grading before metalling
    • Stabilising cut/fill slopes
  • Water control
    • Water control overview
    • Ditches
    • Road drainage culverts
    • Berms and cut-outs
    • Flumes
    • Silt traps and soak holes
    • Silt fences
    • Single culvert river crossings
    • Ford crossings
    • Bridges
  • Applying aggregate (metalling)
  • Repairs and maintenance
    • R&M overview
    • R&M common to new construction
    • R&M of road formation
    • R&M during harvesting operations
    • R&M of river crossings
  • Assisting loggers and harvesting rehab
    • Installing deadmen
    • Installing debris traps
    • Harvesting track rehabilitation (rehab)
    • Harvesting track rehabilitation – cut-outs
    • Landing rehab
  • Want to learn more?
  • Glossary

NZ Forest Road Engineering Manual: Operators Guide

  1.  ›
  2. Water control ›
  3. Berms and cut-outs
 

Berms and cut-outs

Berms are small banks on the outside edge of roads and landings. They direct stormwater away from erosion-prone fills and slip faces to more stable ground. Water then goes to cut-outs, and possibly flumes and sediment traps.

  • The berm was constructed at the same time as the road
  • The berm has protected the fill
  • Grass helps stabilise the berm
  • Berms don’t need to be this wide
  • The berm is already starting to collapse because it has overloaded the fill
  • Berms should not be used to dispose of extra fill, because they get too big
  • The berm is not keyed into compacted fill
  • The fill is not stable
  • Berms protect the large fill
  • The road is shaped so runoff is directed away from the fill via berms to flumed cut-outs
  • The berm has been compacted and keyed into the fill
  • Ponding and scour will likely cause road failure
  • Water should have been cut out before the fill, and not allowed to pool in the middle and scour out and saturate the fill
  • The low point of the road should not be in the middle of the crossing. If unavoidable, use a through-berm flumed culvert to remove water
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