Water & Wastewater Treatment

www.wwtonline.co.uk | WWT | March 2015 | 21 • Innovations ● Sustainable urban Drainage systems (SuDS) were retrofitted on a large scale across a densely populated urban area ● Advanced modelling enabled Dwr Cymru Welsh Water to identify where to concentrate its work, and regular monitoring was put in place to measure its effectiveness ● A high degree of collaborative working with Carmarthenshire County Council and other stake- holders, culminating in a Memoran- dum of Understanding (MOU) over new developments work and road closures. Furthermore, for the programme to work long-term, understanding also had to be reached about planning and development, as new concrete-heavy developments and paving could not be allowed to come in unchecked and undermine the progress that had been made. Fortunately, local, regional and national authorities have united behind RainScape, culminating in a Memorandum of Understanding (MOU) between Dŵr Cymru Welsh Wa- ter, Carmarthenshire County Council, Swansea County Council and Natural Resources Wales. The MOU sets out that every time foul flow is added to the network by a development, compensatory surface water removal work should be under- taken to prevent deterioration in the estuary. At a time when SuDS legislation for new developments is about to be enforced in England through the planning system, and there is a rising interest in retrofitting SuDS across the UK, O'Brien feels that RainScape, and the co-operation of stakeholders in the Llanelli area in particular, serves a positive example of what can be achieved. "The individual schemes that we've done here aren't anything that unusual, but what's really ground breaking is the area-wide scale we've done this on: the modelling and the investigation we did to advance our understanding of where best to do the work," he says. "There's no-one that we can see in the UK that's done anything like the scale of work that we're doing and are still proposing to do in this area." Ofwat has been sufficiently im- pressed by RainScape, and the data Dŵr Cymru has provided on its perfor- mance, to approve its plans for £25M worth of more work in AMP6. The utility believes that once this work is completed it will be able to reduce the volume of CSO discharges in the area by 60% by 2020. "Although we are using this to deal with flooding issues and water qual- ity issues now, we also see the need to insulate our customers from the worst effects of climate change in the long run," concludes O'Brien. "That's why we have set ourselves the target of taking the equivalent of 25,000 houses worth of surface water out of the network in this coming five-year AMP6 period. Our vision is to have a network that meets the needs of our customers for the long term." critical – that together with disrup- tion, was probably the single biggest issue," O'Brien continues. "We did lots of letter drops, open days and drop-in sessions, but we still had people when the work was starting saying 'we had no idea this was going to happen'. So more recently we con- cluded we needed to take a knocking- on-doors approach, and that's really helped." Two-way dialogue has also been necessary with local businesses. A re- cent scheme, completed in December, saw planters installed in an Asda car park, which meant extensive consul- tation with the supermarket about the plans. Most crucially, co-operation with the local authority, Carmarthenshire County Council, has been essential at every stage of the process. Dŵr Cymru's design team met with council officers every two months to update each other on progress and co-ordi- nate actions related to the ongoing Queen Mary's Walk Swale (seen here being tested) would fill to the brim in a 1-in-100 year storm RainScape has been able to tackle runoff by introducing relatively small areas of green space

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