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. Water control overview
 

Water control overview

Good drainage and sediment control are essential. They help protect roads and landings, and reduce the amount of sediment that gets into waterways. Ongoing sediment harms stream life.

  • Drainage is onto stable ground
  • Water is cut off as often as possible, to avoid directing lots of water into one place − where it would scour
  • Culverts on the top and lower sections of the road are lined up to minimise the amount of water forced into the lower road’s ditch
  • Poor water control can quickly cause a lot of damage and erosion
  • This leads to expensive road maintenance work
  • It also generates fine sediment, which can severely damage stream life
  • Drainage is directed away from the fill
  • The fill is contained by slash and stabilised by hydroseeding
  • Water and sediment control were installed to reduce sediment going into waterways
  • Large amounts of fine sediment are in the stream
  • If this was the result of poor practice, it could lead to prosecution
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