Water infrastructure maintenance - Vegetation Management Program

Water Services undertakes programmed vegetation management on Power and Water Corporation's large above ground steel water mains in order to maintain the integrity of Darwin's bulk water system.

The mains are the water lifelines for Darwin and surrounds. Vegetation management and removal is essential to ensure the long term integrity and reliability of the system by reducing water main breaks, leaks and system outages.

There are four key reasons for removing trees and other vegetation from around the water mains:

  1. Trees lift or move the mains pipe causing it to break.
  2. Trees rub against and erode the pipe causing it to burst.
  3. Moisture becomes trapped around the pipe, accelerating corrosion and causing it to burst.
  4. Striking (falling vegetation), damages the pipe, causing the pipe to break.

The work typically begins near Manton Dam and continues along the highway towards the city. Power and Water staff discuss the works with key stakeholders throughout the program's progression.

The scope of the works is as follows:

  • Trees within one metre of the water main are removed.
  • The trees are cut as close as possible to the ground and poisoned.
  • The stumps are then left to rot away.
  • Where possible, we try to leave small shrubs or decorative plants that are not likely to damage the main.

An extensive tree removal program is conducted every decade and each year minor clearing and weed spraying is undertaken.