A flood risk assessment for a school and a block of residential flats on the former site of Putney Hospital, Wandsworth, London
RAB Consultants has recently completed a flood risk assessment for the site of the former Putney Hospital, Wandsworth. The planned development will see most of the site redeveloped as a school and a block of residential flats. Because the site is situated in the Environment Agency’s flood zone 3 at risk of flooding from the tidal River Thames a full assessment of the risk to the developments final occupants was required.
The assessment involved the following:
- A site visit to assess flood risk at the site;
- Assessment of collected Environment Agency data;
- Preparation of a flood risk assessment report in accordance with the National Planning Policy Framework;
- Preparation of a Sequential Test and Exception Test in accordance with the National Planning Policy Framework;
- Desk based assessment of suitable mitigation measures to offset any risk of flooding.
The report concluded that the flood defences along the stretch of the River Thames closest to the site offered sufficient protection for even the most extreme floods modelled by the Environment Agency now and would continue to do so in the future if defences are raised in line with the Thames Estuary 2100 Plan. Because the site was also shown to not be at risk of flooding from all other sources including surface water and drainage infrastructure, it was concluded that the development is appropriate for the flood risk.