Anlaby and East Ella Flood Alleviation Scheme

RICS Social Impact Awards - Infrastructure Works Winner & Winner of The Project of the Year

Overview

Mason Clark Associates carried out the feasibility studies on the Anlaby and East Ella Flood Alleviation Scheme (AEEFAS) in order to secure funding approval for this ambitious project for one of the areas badly affected in the floods of 2007, with over 11,000 properties flooded in the wider catchment area. The floods caused damage and disruption to businesses, as well as distress to the business owners and residents.

A long list of options was drawn up and assessed; the preferred option being the Anlaby and East Ella Flood Alleviation Scheme. This comprises a large diameter storm water culvert which collects overland flows from the Westella Valley and Tranby Hill catchments, and conveys the exceedance flows to a large discrete attenuation lagoon within the urban area of Anlaby.

Activity

Construction activities were separated into 3 phases to reduce disruption, maximise design and construction programme efficiency and deliver benefits promptly. A dedicated Project Management team carried out risk management which included the development of a brownfield site for the lagoon and significant earthworks activities with associated weather risks. In order to better understand the mechanics of the flood flow routes, a detailed virtual flood model was developed. This was the largest of its type at the time and used Infoworks ICM to create an integrated catchment model, requiring close liaison with the software developers. The model was tested and calibrated against the data collected from the devastating flood event of June 2007.

The main benefit of the scheme is to reduce direct damages to 8000 properties in Anlaby and East Ella during flood events. Indirect benefits include community assurance that there is a reduced risk of flooding.

As well as community groups, this project was carried out in partnership and collaboration with the following agencies:

• East Riding Yorkshire Council
• Hull City Council
• Environment Agency
• Yorkshire Water

Results

The scheme reduces pluvial flood risk to 8000 properties in deprived areas of Hull and Haltemprice. Many of the residents within this area would have had no insurance and little income making it much harder to recover from the effects of flooding.

The severe rainfall event of November 2019 resulted in the flood alleviation schemes activating, preventing flooding to up to 500 properties which would have flooded if the flood alleviation scheme had not been constructed.

Other benefits of the scheme include making the area a better place to live and work as a result of the flood risk being reduced. The AEEFAS storage lagoon has been constructed on a remediated brownfield site and includes high quality sports pitches, increasing leisure opportunities. This scheme has given the local community confidence that the risk of flooding has been reduced and has improved people’s wellbeing and overall, inspired a healthier community.

Ian Cook, Managing Director of Mason Clark Associates Ltd, said "We are extremely proud to have been lead designers on this scheme. The scheme comprises a 1.5km, 1.8m diameter tunnel, a new 120,000m³ storage lagoon and interaction with existing watercourses and reservoir. Significant public engagement and support from other statutory bodies were utilised at all stages of this project, generating tremendous support and an environmentally sensitive construction process and robust scheme. Our Engineers have provided dedication to the project that will be of benefit to the community for years to come."

Andrew Cooper, Principal Engineer at East Riding Infrastructure and Facilities said: “We are incredibly proud of the Anlaby and East Ella Flood Alleviation Scheme, which has already been proved to provide protection for many residents. Following the completion of the scheme a severe rainfall event occurred and the lagoons were activated. This event was very well received by the local residents, who are relieved that the flood alleviation scheme has resolved flooding in the area.”

RICS Regional Awards - Winner of Infrastructure Work Category This award honours an outstanding single project or programme of infrastructure works that delivers essential facilities in connection with transport systems, emergency services, supply projects for power generation, water or sewage treatment, sea defences or information technology networks.

Also

RICS Regional Awards - Winner of The Project of the Year This award is presented to the project which has been judged overall as an excellent example of best practice by professionals working in both the built and natural environments.