Posted By Naz Nathu I have been asked to conduct a Risk Assessment for a Swale within a Housing Estate. Could anyone help me with this? In particular I would like information and experience on the protection of the Swales from intrusion

Posted By Arran Linton - Smith See: http://sudsnet.abertay.ac.uk/Swales.htm

Posted By SJA Hi Naz The main risk assessment for a swale would be completed by the designer during the design of the swale and any other part of a SUDS. With regards to preventing intrusion, don't. The idea of swales is that when not in use, they form a natural part of the surrounding environment, the key issues are to ensure that the side slopes are kept shallow and that the swale is not designed too deep, though any competent drainage engineer do this anyway as the flow of water through the swales needs to be restricted, they are not meant to act as a pipe or drainage ditch. You also need to ensure that maintenance staff can easily cut the grass and cross the swales etc. The only location where you may need fencing etc is where a swale discharges into a chamber or pipeline, such as where it passes beneath a road and there may be a significant difference in levels. Correctly designed, Swales are low risk and low maintenance and providing an effective solution to urban runoff issues. I hope that this helps, and if you need any further information, I think CIRIA have published a design guide for Swales. SJA

Posted By SJA JJ Try again, both of Arran's links are fine and will provide the information that you need. SJA

Posted By Andy Petrie I think they called them ditches in my day

Posted By CFT Hi Naz Risk assessing from a design point of view? If so, then the usual cautionary signs should be included as one would expect to see, or if the network is not a particularly big one and is looking after a small estate perhaps a 'partially' covered method, i.e mesh or overground culvert; as for protection from intrusion your biggest consideration will be localised vegetation and on-going maintenance issues. The more concrete we pour the more there is a need to divert/collect/re-channel water; I tend to think of it as an over ground version of a storm water system to assist the underground when we get abnormal levels of rain or snow, the latter seen more to the base of mountainous areas in the North. We have a 300 acre site with a network of swale based drain off channels, it is vegetation every time for me. CFT

Posted By Steve Skinner Peter taylor14 From the EA website: Swales Swales are grassed depressions which lead surface water overland from the drained surface to a storage or discharge system, typically using the green space of a roadside margin. They may be used to replace conventional roadside kerbs, saving construction and maintenance costs. Compared to a conventional ditch, a swale is shallow and relatively wide, providing temporary storage, conveyance, treatment and the possibility of infiltration under suitable conditions. There you go, both links work m8 try again Steve

Posted By SJA Hi JJ My last comment above was not directed at yourself, but at others who have simply made unhelpful comments with reading all of the information posted on the thread. I find that some of the comments made by others mot only unhelpful, but annoying and frustrating. In particular instance I would not expect most safety professionals to know what a Swale is, but as a Chartered Civil Engineer I have been responsible for the design of one or two in my time! Have you managed to open the links posted by Arran as they will answer your questions. Apologies for any confusion caused and I appreciate you are only looking for help/information. SJA

Posted By Steve Skinner Oops sorry should read ........Quite right brett,I should have read the entire thread not skimmed it :-) Steev

Posted By IOSH Moderator All, Both links provided by Arran have been checked and do work. Just make sure you only copy and paste the http address and not the preceding comments made by him (I made the same mistake myself). The comment by Steve Skinner has been hidden purely because it is a cut & paste of the EA website and we don't like that under AUG 2. Carry on. Jon