13 Feb 2024
by Tim Smith

Accelerated and continuous climate change and extreme weather events present a real liability risk to local authorities.

The 2023 National Risk Register confirmed that the main risks associated with climate change are flooding, periods of extreme heat and periods of extreme cold. Local authorities should therefore consider their current procedures and implement adaptations where appropriate to mitigate the risk of potential claims and ensure that they are climate change resilient.

Growth of tree roots

In periods of extreme heat, trees may absorb higher volumes of water to reduce water loss from leaves. Tree roots are consequently more likely to encroach onto neighbouring land which can result in soil dehydration and potential risk of damage to properties. Damage is particularly likely where tree roots extend below or near the foundations of neighbouring properties.

The roots absorb water from the soil beneath the foundations causing certain types of dehydrated soil to shrink, which in turn can result in structural movement. Local authorities should consider adapting their current procedures to mitigate the risk of resulting property damage claims.

Policy adaptation considerations:

  • Consideration of tree register – identifying hot spot areas and prioritising tree inspection based on risk.
  • Increased use of root barriers can prevent the growth of tree roots in the direction of neighbouring properties.
  • Increased use of root bridges can redirect the growth of tree roots away from neighbouring properties.
  • Felling and/or significant pruning based on a proactive system of inspection and maintenance is appropriate for larger trees in close proximity to neighbouring properties.
Growth of Japanese Knotweed

Japanese Knotweed is the most invasive plant in the UK. The high growth rate allows the plant to spread quickly, growing up to 10cm a day between the warmer months of April and October. Periods of extreme heat are extending the peak season of Japanese Knotweed growth. Growth is continuing for longer throughout the year, increasing the risk of encroachment onto neighbouring properties and the prospect of claims for damages in nuisance and negligence due to the encroachment.

Local authorities should consider adapting their current procedures to mitigate the risk of encroachment and resulting property damage claims.

Policy adaptation considerations:

  • Integrated pest management - implementing a multidisciplinary glyphosate-based treatment combining physical, biological and chemical methods can provide potential for a good level of control over Japanese Knotweed.
  • Increased mapping of Japanese Knotweed and recording – consider written records of inspection, treatment and photograph evidence of the reduction in the size and spread of Japanese Knotweed stands.
  • Consider treating a buffer zone around the perimeter of large affected area to try and prevent spread to adjoining properties.

Short periods of heavy rainfall increase the risk of public highways flooding due to surface water and ground water. Excessive rainfall can cause rivers to break their banks and surpass drain capacity. Saturated land caused by excessive rainfall and hard, dry land caused by periods of extreme heat further exacerbate the effects of flooding, as surface water cannot soak into the land and instead runs over the land. Periods of extreme cold intensify the liability risk, establishing an additional risk of ice.

Local authorities must adapt their procedures for dealing with adverse weather conditions and highway management to mitigate the risk of resulting personal injury and property damage claims.

Policy adaptation considerations:

  • Increased frequency of inspection and maintenance - systems including debris clearance, drain clearance and highway management must be reasonably adjusted to account for the increased regularity of flooding and ice.
  • Alternative flood alleviation measures – negotiations with third-parties for use of natural flood plains to avoid flooding incidents and clearance of water ways where appropriate.
  • Multi-agency reviews – regarding best practice and management of flood incidents and impact of occurrence.