From: Colin Wilson Sent: 15 March 2018 09:00 To: alittler@hillingdon.gov.uk Cc: David Howells; George Whitelock Subject: 4198 Jackets Lane - Sustainable Water Management Attachments: suds hierachy check list.pdf; suds design statement.pdf; JACKETS AREAS WITH MH.tiff; JACKETS AREAS.tiff Dear Adam, We have been copied two observations reports from Hillingdon on our surface water drainage design; Ref 67677/APP/2017/4245 – by Richard Phillips Ref 70543/APP/2017/4234 – By Zenab Haji-Ismail We issued our Drainage calculations and drawings some time ago and these do appear to be what the above observations are based on. In both cases they have stated insufficient information has been supplied and they have provided a flow and volumes form. All the information requested is within the MicroDranage calculations and soil report provided. However, I believe some additional attached information will help explain how we derived the scheme. To help dialog and get some of the items in the Observations schedule clear the further information attached explains our design process. It explains why green roofs have not been considered and why pumps are necessary for example, two items your observations pick out. I trust this helps explain we have achieved the best compromise to applying suds for these such small sites on clay based substrata. I also attach snap screen shots of the MicroDrainage calculations showing the areas used and the manholes they are associated to help you. I would very much like to discuss the design with you should you have further queries or believe we should be doing more. Otherwise I look forward to receiving your approval of the scheme to remove the conditions in the planning approval for each site. Colin Wilson Director Richard Hatton Associates 14 Weston Barns Hitchin Road Weston Herts, SG4 7AX T: 01438 350933 F: 01438 740297 www.richardhatton.co.uk This email, including any attached files, is intended for the named addressee only. It contains information that may be confidential and which may also be privileged. Unless you are the named addressee, you may neither copy nor use nor disclose it to anyone else. To do so may be illegal. If you have received this email in error, please notify us immediately and remove it from your system. Thank you. Richard Hatton Associates is the trading name of R Hatton Limited, company registration No. 4809182