Former Irish Glass Bottle & Fabrizia Sites, Poolbeg West, Dublin 4
19. The Developer shall comply with the following conditions from the Drainage Division: b) Detailed attenuation calculations for full suite of rainfall events shall be submitted for written agreement with the DCC Drainage Division prior to the commencement of the development demonstrating that sufficient attenuation storage has been provided within the development to attenuate 1 in 30 year critical storm event + 20% Climate Change. It is not clear from the format of calculations submitted in response to Clarification of Further Information Request how the critical storm event was established. There seems to be a large discrepancy between the previously calculated 30 year attenuation volume included in the initial submission and the attenuation volume required according to the calculations included in the response received for Clarification of Further Information. Justification for the use of applied run-off factors within the calculations shall be provided. c) The 65mm deep Bauder drainage matt indicated on the drawing called SuDS Details Sheet 1 – Rev. PL4 has manufacturer’s declared storage capacity of 10-12 litres of water per m2 and not 65 l/m2 as assumed in the calculations submitted in response to Clarification of Further Information. A revised drawing of the proposed green/ blue roof build up and specification including manufacturer’s declaration of storage capacity of the proposed drainage / reservoir board shall be submitted for written agreement with DCC’s Drainage Division prior to the commencement of the development. The proposed drainage / reservoir board shall have a capacity to retain at least 65 l/m2 and release the water at a controlled rate in order to meet the design intent. d) Prior to the commencement of the development the applicant shall make a written submission for agreement with DCC’s Drainage Division detailing how the overall surface water control rate of 2.4 l/s for the entire development will be achieved by setting control rates at individual sub-catchment levels. Details of proposed flow control devices, roof / podium outlets and their control rates, corresponding catchment sizes and storage volumes shall be provided. e) Detailed surface water drainage layouts for any areas of the development intended to be taken in charge by DCC shall be submitted for written agreement with DCC’s Drainage Division prior to the commencement of the development. All surface water infrastructure in such areas must be constructed in accordance with the Greater Dublin Regional Code of Practice for Drainage Works Version 6.0.