Flood Risk Assessments in Gloucestershire

The River Severn dominates the flood risk picture in Gloucester City and Tewkesbury Borough. Its tributaries, the Chelt, Leadon, Frome and Avon, back up during high Severn flows, causing flooding at locations where the main river is not the direct source. This backwater mechanism is a specific technical challenge. It requires EA tributary model data and an understanding of how the Severn catchment behaves as a system, not just a review of the standard flood zone map. Tewkesbury Borough, at the Severn and Avon confluence, is one of the most flood-constrained town centres in England and requires engagement with the JCS Level 2 SFRA for Gloucester, Cheltenham and Tewkesbury.

Cheltenham presents a different flood risk profile. The River Chelt flows through the town centre, culverted in places and regulated by a flood alleviation scheme. But intense rainfall events regularly overwhelm the older drainage infrastructure. The Cheltenham Borough SFRA identifies surface water flooding as the dominant risk for the majority of planning applications in the town. A drainage strategy for Cheltenham must address the surface water picture specifically, not just reference the main river flood zones.

Gloucestershire County Council as LLFA publishes its own SuDS design and maintenance guide. Every major development across the county must comply with it, and GCC Highways assesses drainage submissions as the statutory SuDS approving body. Stroud District, South Gloucestershire and the Forest of Dean each have their own SFRA requirements that apply alongside the county-level guidance. For development near the River Frome in Stroud, the River Wye in the Forest of Dean or the Avon in the south of the county, site-specific FRAs must engage with the relevant district SFRA evidence.

• Development in Flood Zone 2 or 3 along the Severn, Avon, Chelt, Leadon, Frome, Wye or any tributary
• Development of 1 hectare or more in Flood Zone 1
• Development requiring a surface water drainage strategy under Gloucestershire County Council SuDS guidance
• Sites near Severn tributaries where backwater flooding creates risk even behind Severn flood defences
• Development in the JCS growth areas for Gloucester, Cheltenham or Tewkesbury requiring Level 2 SFRA engagement
• Development in Cheltenham where surface water and drainage capacity are the primary planning concerns

We were appointed by Gloucestershire County Council through competitive tender to deliver over 100 property-level flood assessments following Storm Henk. We have worked directly with the council, understand the county’s drainage framework and know how the Severn backwater mechanism works in practice, not just in theory.

Our FRAs for Gloucestershire planning applications engage directly with EA Severn and tributary model data. We treat the flood zone as the starting point for a wider engineering exercise. We assess backwater risk, drainage capacity constraints and finished floor level requirements together, so the assessment supports the development rather than creating obstacles to it.

FPS Environmental has been delivering flood risk and drainage consultancy for over 12 years. We cover Gloucester City, Cheltenham, Tewkesbury, Stroud, Cotswold and Forest of Dean districts.