The Leeds Flood Alleviation Scheme Phase 1 (FAS) has been built to protect the city against flooding from the River Aire. Working in close partnership with Leeds City Council, the Environment Agency, Yorkshire Water Services and the Canal and River Trust, phase 1 of the project focused on the lower lengths of the river including the area of Holbeck.
An earlier flood protection scheme that was suggested before Arup’s input in 2011, proposed a network of fixed walls and embankments built above the forecast heights of the flooded river. Early designs indicated that these walls would need to be over eight feet high in places to provide suitable protection. The improved design protected the character of the beautiful city waterfront for both wildlife and the public without affecting city views.
The Leeds FAS phase 1 principally protects against flooding of the River Aire
The FAS will most notably bring confidence for regeneration, economic growth and benefits to the people of Leeds for being the 'Best City for Health & Wellbeing;' as well as protecting 3000 homes and 500 existing businesses.
Arup’s team of expert engineers designed an innovation solution that helped maintain the connection between the river and city. Phase 1 saw the removal of the two main navigation weirs at Knostrop and at Crown Point and replaced them with new mechanical moving weirs. Normally, these new mechanical weirs will be in a raised position to allow barges to navigate up and down the river without compromising city views. However in periods of dangerously high flood levels, these weirs will progressively lower and reduce the height of the flooding to the lowest practicable level.
Landscaped flood defences and the modification of existing buildings were also included in Arup’s design, to ensure the highest standard of flood protection to be achieved in both the short and the long term.