National Highways: Flood Control

The Department does not plan to make an assessment of the potential impact of maintaining balancing ponds owned by National Highways on the climate resilience of the transport network; National Highways already follow prescribed maintenance regimes so the capacity of balancing ponds is retained.

The provision of balancing ponds for flood mitigation has been common practice in highway design for many decades and is usually determined as part of a flood risk assessment during the design of a road. It should, however, be noted that the provision of balancing ponds is not usually for the protection of the highway, but to prevent downstream flooding once the water leaves National Highways’ boundary.

Additionally, I would like to reassure you that that climate change requirements are included in National Highways’ drainage design standards, having been introduced in 2006. Since then, National Highways drainage schemes, including balancing ponds, are designed with the latest climate change allowances in accordance with relevant published national policy to ensure resilience to flooding.