Regional flood management by combining soft and hard engineering solutions, the Norfolk Broadlands

The Broadland Flood Alleviation Project (BFAP) is a 20-year (2001-2021) programme to upgrade about 260 km of flood embankments protecting roughly 30,000 hectares of low-lying land in the Norfolk Broads, England, a nationally important wetland and tourism area attracting over 7 million visitors a year. The embankments, built from marshland peat and clay, had deteriorated and were vulnerable to breaching by modest tidal surges, a risk compounded by projected sea-level rise of up to about 40 cm by the 2080s.

The project's first step aimed to restore embankments to their 1995 crest height to reduce the risk of breaching, while a second, ongoing maintenance phase covers grass-cutting, erosion control, channel clearance and periodic crest top-up as banks continue to settle.

Across 40 discrete flood-protection compartments, works combined hard engineering (bank strengthening, in-place crest raising) with soft solutions such as bank 'setback' or 'rollback' onto a new landward alignment and the creation of natural reedbed as erosion protection against boat wash and river flow, replacing ageing steel and timber sheet piling. By 2016 the improvement phase was complete: about 200 km of banks strengthened, 50 km set back, 7 km re-piled, 20 km given other erosion protection, and 14.5 km of old piling removed. Flood-risk-management functions were delegated to Broadland Environmental Services Ltd (BESL), a Private Finance Initiative company owned 90% by BAM Nuttall Ltd and 10% by Halcrow Group (now CH2M HILL).

Total project costs were projected at about GBP 136 million (GBP 107.7 million construction, GBP 31.3 million maintenance to 2021). During a 2013 flood event with water levels comparable to the severe 1953 flood, the upgraded defences held with only two breaches and no properties flooded, compared with far more extensive breaching and flooding in 1953. The scheme is reported to protect 1,700 properties, the A47 highway, the Norwich-Great Yarmouth railway and 24,000 hectares of agricultural land, alongside co-benefits including 100 km of upgraded footpaths and 55 hectares of new freshwater reedbed habitat.

A key success factor identified is the public-private partnership structure, with the Environment Agency and BESL treated as equal partners bringing complementary strengths. Some landowners opposed bank setback on their land, which in some cases required re-aligning the new banks around the opposing landowner's property, leaving it without the planned protection. The project received the East of England Merit Award from the Institution of Civil Engineers in 2017.