WET News

DECEMBER 2014 WET NEWS 19 Combining soft and hard SuDS meant developable land could be freed up. A solution: Burying storage tanks T he solution was to move a significant proportion of the storage capacity un- derground to free up more of the site for development. As a con- sequence the design was sub- stantially amended to include a combination of two precast con- crete storage tanks buried be- neath the development's access road. "For this development, us- ing the large-capacity under- ground storage solutions was a critical part of the solution," says Kevin Pryor, the engineer at Edwards & Edwards who de- signed the SuDS solution for this development. The storage-based solution provides attenuation for run-off from the site's upper catchment area. The largest tank is formed from 62 precast concrete box culvert sections, each measur- ing 2m x 1m and produced by Concrete Pipelines System Asso- ciation (CPSA) member com- pany FP McCann. The tank has the capacity to store 360m3 of runoff. The scheme also includes a second, smaller capacity 70m3 attenuation tank formed from 1.2m diameter precast concrete pipes. The tanks have integral dry weather flow channels to maintain water velocities at times of low rainfall. Both tanks have subse- quently been adopted by Seven Trent Water. From the attenuation tanks the water flows, via two precast concrete vortex flow control cambers, to a lower catchment area. These flow controls throt- tle back runoff to the storage tanks during periods of high rainfall intensity and or extended rainfall duration. Runoff is released, via a headwall, into a small natural SuDS feature comprising a swale and a permanently wet micro-pool. The pool has the capacity to store 711m3 of runoff while bringing additional ecological benefits to the development. A third flow control chamber lim- its the runoff from this pool into an adjacent, existing water- course via a second headwall. Pollutants Alongside flood management the implementation of SuDS is also about improving water quality. A well designed SuDS scheme will simulate the many natural processes to remove pol- lutants from the surface water. Slowing down the conveyance of water, for example, is a sim- ple mechanism that enables sediments containing pollutants to settle out so that they can be captured and routinely removed from the system. For the Farmlands develop- ment, improved water quality is achieved using a pioneering proprietary treatment system in combination with vegetative treatment components designed to deal with pollutants expected in the runoff. Edwards & Edwards is working with Leices- tershire County Council High- ways Division to trial the design of a prototype precast concrete filter treatment chamber situ- ated beneath an area of residen- tial driveways. The unit incorporates an innovative filter to remove hydrocarbons, heavy metals and sediment before the run-off is released into the balancing pond where micro-organisms will remove nutrients and pesti- cides from the surface water. Pryor is a proponent of com- bining hard and so™ SuDS solu- tions. "We can free up develop- able land by using hard SuDS solutions while also enhancing the landscaping by including so™ SuDS elements as part of the combination," he says. n Stuart Crisp is business development director of the CPSA. www.concretepipes.co.uk Balmoral Tanks SALES Unit 2, Coomber Way Ind Est, Croydon, Surrey CR0 4TQ Tel +44 (0)208 665 4100 Email watertanksales@balmoral.co.uk Global water, wastewater and processing storage solutions We provide products and services to the following sectors: ¢ Anaerobic digestion ¢ Biofuel and Biomass ¢ Civil engineering ¢ Desalination ¢ Drainage ¢ Fire fighting www.balmoralindustrialtanks.com Providing turnkey services to the water, wastewater and processing sectors, Balmoral Tanks offers what is potentially the widest range of accredited tanks from a single supplier in the world. When this is supported by unrivalled engineering design experience and industry-leading customer service, installation, maintenance and repair services, why consider going anywhere else? Trust us with your project and in return we'll deliver a watertight quality promise. ¢ Irrigation ¢ Petro-chemicals ¢ Potable and Non-potable water ¢ Rainwater harvesting ¢ Storm water attenuation ¢ Wastewater and Effluent treatment Join today Membership has its benefi ts THE BUSINESS OF UTILITIES ✔ Essential 32-page weekly magazine ✔ Unlimited access to utilityweek.co.uk ✔ Daily news alerts ✔ 10% discount on Utility Week conferences ✔ Special editions and reports ✔ VIP drinks reception at Utility Week Awards ✔ Energy Supply Handbook print and digital ✔ Digital editions plus back issue archive ✔ 25% discount on job adverts ✔ Members lounge at Utility Week Live (incorporating IWEX) The essential reference tool for over 50 years 2015 UWmember-130x88-WWT advert.indd 1 21/11/2014 12:39 WHATEVER THE PE PIPE DIAMETER WHATEVER THE COIL LENGTH* There's a Steve Vick International Trailer for its safe, easy transportation, storage and dispensing. *From 40mm diameter pipe right up to 180mm diameter and coil lengths up to 500 metres. Please contact us for more information: Steve Vick International Ltd Treenwood Industrial Estate Bradford-on-Avon, Wiltshire BA15 2AU Phone: +44 (0)1225 864 864 info@stevevick.com www.stevevick.com The water flows through two precast concrete vortex flow control cambers to a lower catchment area. These flow controls throttle back runoff to the storage tanks during periods of high rainfall intensity UK Offi ce Tel: 01756 748519 Irish Offi ce Tel: 00353 46 9543646 sales@reliant-tanks.co.uk www.reliant-tanks.co.uk Celebrating over 40 years of successful tank building We are now pleased to announce the opening of our new Irish Offi ce to service the Irish market • Permastore R Glass-fused-to-Steel tanks • Industrial - Municipal - Agri/Biogas • Gas-Holders - Supply, Install and Service • Tank Inspection and Repairs • Digesters - Built to meet requirements

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