“With the onset of climate change, better understanding of the risks trees pose for buried water utility assets is vital to asset maintenance,” says UKDN Waterflow (LG) Ltd director Richard Leigh.
Tree roots and their impact on drainage systems
The paper highlights surprising findings from Swedish & UK researchers and the Arbroricultural Adivsory and Information Service (AAIS). Common perceptions suggest that tree roots directly cause damage to pipes. Yet research discovered in the majority of cases, roots only take advantage of previously damaged or vulnerable pipes.
Tree roots can exert a pressure of up to 20 bar per sq. cm, far greater than the 6 bar per sq cm that most rubber seals can resist. While it might take up to 20 years for root ingress to occur, they can eventually break into a pipe by displacing a seal. Meanwhile, if a water pipe is leaking into the ground, tree roots can grow around it to absorb the moisture. This can cause soil drying and subsequent pipe movement, exacerbating cracks and gaps in joints. Additional nutrients and water in pipes encourage rapid growth to the point where the roots can fill the pipe.
Overcoming and preventing tree-related drainage problems
UKDN suggest the best way to guard against tree root ingress is to put in place a rigorous planned and preventative drainage maintenance system. Key elements include:
- Reviewing tree planting plans and avoiding species that have particularly vigorous root systems.
- Carrying out regular CCTV drainage surveys to check for defects and signs of root ingress.
- Mapping drainage systems to support effective SuDS planning and tree planting.
- Keeping pipes clean through water jetting.
- Removing tree roots with the most appropriate, cost-effective no-dig method. This may involve high pressure water jetting, electro-mechanical cutting, or robotic cutting.
- Installing glass reinforced plastic liners to create a strong barrier for pipes most at risk.
Download the white paper here for more insight and solutions including discussion on urban drainage systems, insurance disputes and the future of tree roots and drains from UKDN Waterflow.