Following extensive flooding in 2015, AECOM supported the Environment Agency in delivering a flood alleviation scheme for York to protect communities and businesses.
The City of York has a long history of flooding and has a series of existing flood defences already in place. However, the Boxing Day flood in December 2015 caused wide-scale disruption to multiple communities. The flooding affected over 600 homes along the River Ouse and River Foss, highlighting the need for all authorities with a responsibility for managing the risk of flooding to work together to minimise this threat.
AECOM identified holistic hard and soft solutions to adapt to climate change for the management of flooding in York. Our role involved completing initial assessments, options appraisals, and detailed designs for the scheme.
Enhancing flood protection
Following 23 initial assessments, more than 70 engineering options were proposed to provide a consistent standard of protection across the city. AECOM was appointed for the full range of integrated services to protect 2000 properties and businesses throughout the City of York. Subsequently, we developed detailed designs and provided onsite support throughout construction.
Conserving history
The project involved working around some highly sensitive heritage sites including Museum Gardens and Bishopthorpe Conservation Area. Our heritage and landscape specialists ensured the designs minimised any negative impacts to York’s heritage assets. Working closely with the Environment Agency, City of York Council and Historic England, we agreed a clear, secure path to Scheduled Monument and Listed Building consenting.
Proactive stakeholder engagement meant that considerations were addressed from the outset and during construction to avoid any potential delays. The designs complement the visual setting and continue to provide public access to the river for community use.
Modelling and cost analysis
Existing hydraulic modelling data for the River Ouse was used to undertake the analysis of the baseline flood risk. We identified properties which would be protected by the various options, and further modelling of the preferred options ensured that any new defences did not exacerbate flood risk elsewhere. Detailed analysis of the costs for each element was developed by our specialist river engineers, including the calculation of capital and whole life costs, covering future operational, maintenance and replacement costs.
From design to delivery
Following our modelling analysis and optioneering, we produced detailed designs, submitted planning for the flood cells and completed the associated environmental assessments. Taking carbon into account, we completed carbon footprint assessments to consider the full lifecycle of the flood defences, through construction, operation, and maintenance. We continued to support the Environment Agency in providing site support throughout the construction works. AECOM’s holistic approach on the York Flood Alleviation Scheme has delivered added value to residents and business owners alike. Not only will the community benefit from the advanced flood protection that the scheme promises, but the city’s heritage assets have been preserved.