Physical context and flood history
The city of Leeds is located in the county of Yorkshire in North England. There are a number of main rivers within the district; including the River Wharfe (in the north and east) and the River Calder (in the south), which joins the River Aire at Castleford (Environment Agency, 2010). The River Aire drains two thirds of the district and flows directly through the city of Leeds. In the past, this has caused significant flooding, most notably in 1946, 2000 and 2007.
The city of Leeds is exposed to fluvial flooding from the River Aire, as well as surface water and sewer flooding; with significant floods occurring in 1946, 2000, 2002, 2007 and 2012 (with the latter two events attributed to surface water). In terms of fluvial flood risk, an estimated 2,000 to 5,000 properties are vulnerable to the 1% annual probability fluvial flood (assuming no flood defences are in place; Environment Agency, 2010). To minimise the likelihood of flooding, there are currently 249 defences along the River Aire, with 70% of these providing at least a 1 in 50 year standard of protection (Environment Agency, 2010). In addition to flood defence, all five of the STAR-FLOOD Flood Risk Management Strategies (FRMSs) are embedded in the approach to FRM. Furthermore, within Leeds city there are plans to take further action to reduce flood risk from all sources.
A number of high priority measures have been proposed to minimise the likelihood of flooding in the Leeds district by 2018. Of interest for this research is the River Aire Flood Alleviation Scheme (RAFAS) (http://www.leeds.gov.uk/residents/Pages/FloodAlleviationScheme.aspx) in Leeds City Centre. Construction began in January 2015 and will involve a number of different measures, including;
The use of movable weirs to regulate water levels for navigation and flood control. These will replace existing fixed weirs at Crown Point and Knostrop. Importantly, this is the first time that such a measure has been employed in the UK.
- Removal of the island at Knostrop Cut to merge the River Aire with the canal (see figure).
- Flood walls and ‘hard landscaping’ in the city.
- A new fish pass.
When completed, the RAFAS will provide the city centre a 1 in 75 year standard of protection against flooding from the River Aire and Hol Beck. Whilst this may seem like a comparatively low safety standard it is noteworthy that prior to the RAFAS there was a proposal to construct another scheme to provide a 200 year safety standard. Numerous factors have been attributed to the decision to revise the original scheme, which will be examined further through this study.
This case study will primarily focus on understanding the governance and decision-making processes around the selection, funding, implementation and construction of the new scheme as well as its position within the wider flood risk management governance framework. There are a number of issues why this case is of interest to the STARFLOOD project:
- The Leeds city centre River Aire Flood Alleviation Scheme (RAFAS) represents an innovative project and will be the first time that moveable weirs will have been installed in the UK.
- Investigation of the decision to implement a revised scheme designed to a 1 in 75 year safety standard and the reasons which led to the previous project (based on a 1 in 200 year safety standard) to be abandoned.
- Flood risk governance in the context of a city centre location, and its place within wider local priorities. Flood risk management within the context of a highly developed area where protecting businesses and stimulating economic growth. The spectrum of sub-flood risk governance arrangements will be explored with these multiple priorities.
- This case study provides an example of a location whereby a Local Flood Risk Management Strategy has been implemented and therefore this type of strategy and the cooperative relationships that exist can be evaluated.
There are a number of specific questions to address in Leeds, listed below:
- What factors influenced the decision to provide a 1 in 75 year standard of protection?
- To what extent can the RAFAS be adjusted to accommodate future risk?
- What are the tensions/barriers encountered in delivering the RAFAS? How are these being resolved?
- How is the LFRMS implemented and to what extent is there evidence for effective partnership working in Leeds? What are the barriers to partnership working? Is there scope for ‘bridging mechanisms’? In what form should these exist?
- How is spatial planning in the context of a city centre location which prioritises economic growth taking material consideration of flood risk? To what extent can spatial planning in Leeds be held-up as an example of ‘good practice’?
- To what extent does the governance arrangement for FRM support societal resilience to flooding?
- To what extent are options for sustainable urban drainage being considered and/or incorporated and implemented into the urban landscape?
- How have arrangements for flood risk governance evolved over time? What are the driving forces for stability and/or change?
For further details contact Sally Priest at S.Priest@mdx.ac.uk