Flood Management and Drainage

Managing water in a built-up catchment

Flood management is a significant concern in parts of Locks Heath, where the replacement of permeable farmland with impermeable housing, roads and car parks has altered the natural drainage patterns and increased the risk of surface water flooding during heavy rainfall. Understanding the flood risk is important for residents, homebuyers and anyone involved in planning decisions in the area.

The main flood risk in Locks Heath is from surface water, which occurs when rainfall exceeds the capacity of the drainage system and water accumulates on roads, in gardens and in low-lying areas. This type of flooding is distinct from river flooding or coastal flooding, although the proximity of Hook Lake and the tidal influence of the Solent adds complexity to the drainage picture in the southern part of the area.

The drainage infrastructure in Locks Heath was designed and built during the development period and reflects the engineering standards of the 1960s and 1970s. The system of underground pipes, culverts and surface drains was sized for the rainfall patterns expected at the time, but the combination of increased development, climate change and the intensity of modern rainfall events means that the system can be overwhelmed during heavy storms.

Problem areas for surface water flooding are known to residents and to the agencies responsible for drainage. Low points in the road network, areas where the drainage system has capacity constraints, and locations where water runs off hard surfaces and accumulates are all vulnerable during prolonged or intense rainfall. The council's surface water management plan identifies these areas and sets out measures for reducing the risk.

Property owners can take steps to reduce flood risk on their own land. Maintaining gutters and drains, ensuring that rainwater downpipes are connected to the drainage system, avoiding paving over front gardens with impermeable surfaces, and installing water butts to capture roof runoff all contribute to managing surface water. These individual actions, multiplied across thousands of properties, can make a meaningful difference to the overall flood risk in the area.

The planning system requires new developments to manage their surface water through sustainable drainage systems, known as SuDS. These systems use techniques such as permeable paving, swales, attenuation ponds and green roofs to slow the flow of rainwater and reduce the volume reaching the piped drainage network. Any new development in Locks Heath must demonstrate that it will not increase flood risk to existing properties, which is an important safeguard for residents.

Climate change projections suggest that heavy rainfall events will become more frequent and more intense in southern England, which means that flood risk in areas like Locks Heath is likely to increase over time. Adapting to this changing risk requires investment in drainage infrastructure, improvements to existing systems and continued vigilance from residents and authorities.

For homebuyers, checking the flood risk of a property before purchase is advisable. The Environment Agency's flood risk maps are available online and show areas at risk from different types of flooding. Solicitors acting on property purchases routinely obtain flood risk searches, and the results can influence mortgage availability, insurance costs and the purchase decision itself.

The agencies responsible for flood management in the Locks Heath area include Hampshire County Council as the lead local flood authority, Fareham Borough Council as the planning authority, Southern Water as the sewerage undertaker, and the Environment Agency as the national flood risk regulator. The interaction between these bodies is complex, and residents experiencing flooding problems may need to contact more than one agency to get a response.