WET News

14 WET NEWS MARCH 2016 F lood risk is now a major concern for home owners and businesses across the UK, especially in flood prone areas. Recognising the value of sharing information and working together to identify the most suitable solutions to surface water flooding problems, Northumbrian Water Group (NWG) and local authority South Tyneside Council (STC) entered into a partnership agreement. Their goal was to resolve the issues faced by the Fellgate estate in Jarrow, Tyne and Wear, which has a long history of flooding and suffered extensive property damage in 2012. The project successfully implemented the partnering and sustainability philosophies set out in Defra's Surface Water Management Plan (SWMP) guidance. By demonstrating how efficiently a partnership approach can deliver, it has paved the way for future schemes. Sharing Surface water flooding in the Fellgate estate originated from sewers, highway drainage, runoff from land, small water courses and ditches during heavy rainfall. MWH was appointed as designer and Esh Construction as contractor in the NWG and STC partnership. The goal was to reduce the risk of flooding and provide wider benefits for the residents and community. This collaboration jointly delivered a solution containing both conventional sewer network enhancements and sustainable measures to manage surface water including swales, bunds and detention basins. Key to project success was: • Sharing knowledge to get a common understanding of the problems and using lat- est modelling techniques to understand risk • Identifying Sustainable Drainage Systems (SuDS) where feasible over con- ventional drainage • Identifying value-add opportunities such as bio- diversity enhancement, amenity and education • Engaging with the commu- nity throughout the project Works were phased to ensure below ground construction was completed before above ground earthworks to minimise disruption to the community. During the first phase (construction September 2014 – May 2015), NWG invested £2.5M to upgrade the surface water sewer network, which has significantly reduced the risk of sewer flooding. In the second phase, funded by STC, the Environment Agency Flood Defence Grant in Aid (FDGiA), local levy and private contributions (£2.3M in total), Reducing risk in more ways than one ONSITE Flood Risk MAnAgeMent delivered surface water management measures to protect against flooding up to the one-in-100-year return period. Statutory powers Ian Davison from NWG commented: "We worked collaboratively from the start and early, informal discussions developed into an agreement for joint delivery. It meant we could look at the flooding issues holistically and share funding and responsibility. Each partner's statutory powers helped us through the planning and consenting processes and led more easily to agreement on adoption and maintenance. "We estimate that by working as partners, sharing the same consultant and contractor, we were able to reduce overall project costs by 36%. Specifically, the implementation of SuDS over a traditional piped solution is estimated to have reduced the construction cost by over £2M and our partnering agreement enabled STC to accelerate their works so residents benefitted earlier." The contribution of each partner to the overall cost was based on the benefit each partner received from the scheme. The project was managed through a New Engineering Contract, (NEC) which has in-built risk management opportunities and the team held regular meetings and used an online collaboration site to share information and openly discuss risks and opportunities. The works were procured through the NWG framework suppliers, which permitted early contractor involvement and reduced construction risks. It was felt that risks were much reduced compared to what they would have been had each organisation been running independent projects. Technically natural MWH's design approach needed a team with a wide variety of skills. This included a landscape architect who designed a natural look and feel to the measures through a landscape plan, planting scheme and habitat design, and an ecologist who advised on planting and liaison with schools. MWH created an integrated model for the study, which included a representation of the sewerage system, surface water drainage system, watercourses and rural runoff from fields and green space. This enabled it to quantify the flood risk at each property, which was necessary to obtain the FDGiA funding. AutoDesk's AutoCad Civil • When a flood-prone estate in tyne and Wear needed a surface water management solution, could a partnership approach tick all the right boxes? Yes, says MWH's Chris Mclarnon. projEcT SpEcS • Provide a surface water management solution to a flood-prone site in tyne and Wear • share knowledge to get a common understanding of the problems • Use latest modelling techniques to understand risk • identify suds where feasible over conventional drainage • identify value-add opportunities such as biodiversity enhancement, amenity and education 3d visualisation of the completed scheme, which had input from a landscape architect and an ecologist

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