Over a 1,000 properties could flood in 'once in a century' weather event

Flooding in the Brentford area

Over a thousand properties are at risk from surface water flooding according to a report commissioned for the council.

The details emerged with the publication of an updated Surface Water Management Plan (SWMP) by Hounslow Council.

This aims to help the Council understand the causes and effects of surface water flooding and agree the most cost-effective way of managing flooding risk for the long term.

Surface water flooding occurs when short duration, intense rainfall cannot infiltrate below ground or enter drainage systems and runs overland. It is intensified when soils are saturated or in urban areas with impermeable ground. The excess water can pond at local low points and often form flow pathways along roads, built up areas or open spaces.

The borough is divided into a number of catchment areas to assess the risk of surface water flooding. There are over six hundred properties (mostly residential) which are at risk from a once in 100 year event in East Brentford with over 2,000 at risk from a once in 1,000 year event.

Most flooding incidents in this area occurs in the TW8 (9) postcode area which is downstream from a major surface water flow path from Ealing to the River Thames.

The West Brentford area, which is the other side of the river Brent has over 300 properties deemed at risk from a once in a century weather event. 56 of these properties are in Brentford End close to the River Brent.

The Plan outlines how Hounslow uses modelling to identify flooding hot-spots and it will influence future council policies such as investment in infrastructure, drainage maintenance, emergency planning, increasing public engagement and understanding of the causes of flooding, land use planning and future housing developments.

The Plan also sets out how the Council can use co-ordinated action plans with partners such as neighbouring boroughs, Thames Water, the Environment Agency, the Greater London Authority (GLA) and Transport for London (TfL).

The councils says it is working with these agencies on the feasibility of several long-term projects to introduce improved and sustainable drainage systems to help tackle flooding in the future. The Thames Water Strategic Partnership (TWSP) is a five-year project running from 2020-2025 which will see £3million invested to improve surface water management by incorporating sustainable drainage systems across the Borough. Initial investigations will be carried out this autumn and winter.

It is also working with the Environment Agency on area-specific Flood Alleviation schemes which will cover Northwest Hounslow; Feltham; Isleworth and Brentford End; Chiswick and Grove Park and will also involve installing sustainable drainage systems.

The council highways team already uses specialist equipment to regularly unblock gutters and drains around the Borough to prevent localised issues.

Cllr Pritam Grewal Hounslow Council Cabinet Member for Contingency Planning, Resilience and Flood Risk Management said, “Unfortunately we saw a number of flooding incidents during heavy rain this summer and this Plan sets out what we intend to do to try and minimise the effects of flooding for residents as part of our wider Climate Emergency Action Plan.

“Every flooded house causes considerable expense, not to mention the stress and emotional toll, so we would encourage residents to also take action to reduce the risk of flooding if they can, and make sure they are prepared in advance if flooding does occur. Planning ahead can mean checking your home’s flood risk and signing up to flood warnings, as well as taking some simple steps such as checking your insurance, knowing how to turn off your gas, electricity and water or finding out where to go to get help.”

December 10, 2021