NEC Project of the Year 2017 finalist: Leeds Flood Alleviation Scheme (LFAS) Phase 1
Value: £50 million
NEC Contracts used: NEC3 PSC Option C, NEC PSC Option E, NEC ECC Option C
Start-Finish dates: April 2013 to August 2017
Main Project Team: Leeds City Council (LCC), Environment Agency (EA), BMM JV (Bam Nuttall Mott MacDonald), Arup
The Phase 1 Leeds Flood Alleviation Scheme (LFAS) is one of the largest river flood defence projects in the country and reduces the risk of devastating physical and economic damage which can occur from flooding whilst supporting wider infrastructure for the region and encouraging further investment.
Since the announcement of government funding little over four years ago, the organisations involved have made rapid progress working with multiple stakeholders from different sectors to develop proposals, drive down costs, secure external funding, and construct the first phase of works. The complexity of the project in a difficult environment was identified as a significant risk however a total of six major procurements have been successfully completed with the spirit of mutual trust and co-operation firmly embedded resulting in the project being on programme to complete in August 2017 within the £50million budget despite northern Britain receiving some of the highest rainfall on record during this period, reinforcing the importance of the project.
The first phase reduces the flood risk of over 3,500 residential and commercial city centre properties together with key access routes to the train station area, telecommunications, internet facilities, electricity sub-stations and over 300 acres of developable land. The scheme has created 150 direct jobs and safeguards 22,000 more over the next 10 years, supporting the further growth and regeneration of the Leeds City Region economy with particular emphasis on the newly protected South Bank of the city (Europe’s largest regeneration area with potential to create 35,000 jobs and 4,000 homes, and the terminus of HS2).
One of the key components of the project is the replacement of existing fixed Victorian weirs at two locations with innovative mechanical weirs, placing Leeds at the cutting edge of national flood defence schemes. The new moveable weirs allow a significant reduction in the height of the high quality walls and embankments, most under 1.2 metres which together with terracing and landscaping maintains physical and visual connectivity with the waterfront. This use of pioneering technology is the first of its kind for a flood protection scheme in the UK, and is attracting much interest both nationally and internationally.
The removal of a manmade island which separated the river and canal over a 600 metre stretch has improved a bottleneck for flows and excavation of this 180,000 tonnes of material has been reused on a local development site and for the scheme in the diversion of the Trans Pennine Trail used by walkers, cyclists and horse riders across the Pennines. The diverted section of the Trail is designed to improve the natural wildlife environment and includes an iconic new bridge over one of the weirs creating a new Gateway into Leeds. Ecological enhancements have also been introduced through the creation of fish spawning habitats and diverse flow conditions, complemented by new fish, otter and elver passes at both of the weirs, resulting in salmon being spotted through the city centre for the first time in over 200 years.