Flood Risk: Development Proposal on Former Farmland, Shropshire
We were asked to assess the potential significance of flood risk to land upon which a two house residential development was being proposed on a site formerly used as a battery hen farm in east Shropshire.
The site was located close to the river flood plain and flood risks from all sources were investigated. The increase in surface water runoff from the site, due to the impact of the proposed development, was also considered.
Our FloodSmart Report showed that the level of flood risk was statistically insignificant, and that the off-site flood risk due to surface water runoff from impermeable surfaces was actually found to decrease with the proposed development.
In cases where properties are close to a flood plain, our Flood Risk Assessment can provide the confidence needed for development to progress.
We were asked to assess the nature and potential significance of flood risk to land upon which a two house residential development was being proposed on a site formerly used as a battery hen farm in east Shropshire.
The site was located close to the river flood plain and flood risks from river, surface water runoff and groundwater sources were investigated. The increase in surface water runoff from the site, due to the impact of the proposed development, was considered and the flood risk assessment followed the standards outlined in the National Planning Policy Framework (NPPF, 2012).
Our detailed review of the data indicated that, even though the site was very close to a river, it was identified as lying outside of the active flood plain, within the Environment Agency’s Flood Zone 1, where the probability of river flooding is less than 0.1% annually. In such instances the Environment Agency is unlikely to object to a development since there is reasonable confidence that the property will not be damaged by flooding during a river flooding event.
Additionally, the flooding history showed no reported floods at or within 250 metres of the site, and the site was not at risk due to a breach of flood defences as there were none within the surrounding area. It was also identified that there were no areas within 50 metres of the site at risk of groundwater flooding.
We assessed the off-site flood risk due to surface water runoff from impermeable surfaces and we concluded that the risk was actually found to decrease in the proposed development, since through careful design and use of permeable surfaces, the proposed residential buildings had a smaller impermeable footprint than the existing farm buildings.
The resulting reduction in impermeable hardstanding and introduction of permeable surfaces complies with the principles of a Sustainable Drainage System (SuDS) and therefore no further SuDS features were required, although we are able to offer the design of additional SuDS features if required. Our consultants are able to tailor suitable SuDS options to fit with the site conditions accordingly.
The FloodSmart Report represents great value and offers clarity to make informed decisions.
