Even during smaller incidents, any diversion of floodwater should be done in consultation with, and the consent of the relevant responsible agency, such as:

• The environmental agency
• The local authority responsible for surface water drainage
• The local sewerage undertaker
• The landowner

There may be unintended consequences as the diversion of floodwater may:

• Overwhelm the capacity of surface water drainage systems
• Have a detrimental impact on sewage works
• Affect biosecurity 
• Result in the flooding of unaffected areas
• Cause damage to other areas
• Negatively impact the flood management plan

In a rapidly developing incident or if there is a threat to life, if it has not been possible to obtain prior consent, the relevant responsible agency should be notified about the action that has been taken as soon as possible.

It may be beneficial to establish memoranda of understanding (MoUs) with responsible agencies to determine roles and responsibilities for diverting the flow, or improving the drainage, of floodwater.

Divert the flow of floodwater

It may be possible to divert the flow of water to either prevent flooding or protect assets. This can be achieved by:

• Using pumps to redirect water
• Making use of existing water management systems
• Excavating channels to direct the flow
• Erecting barriers

During larger floods, diverting the flow may allow areas to be protected. Areas of importance should be identified, such as:

• Those containing Critical National Infrastructure (CNI)
• Receptors of contamination, which could include water supplies
• Important transport networks
• Built-up areas

Improve the drainage of floodwater

Removing blockages in drainage systems and waterways is not the responsibility of the fire and rescue service. However, if it is appropriate and safe to do so, removing objects that are preventing floodwater from draining away may prevent or reduce damage. Ideally such action should not be taken until the consent of the relevant responsible agency has been obtained.