Hi just need a little advice on permanent means of access?  is it acceptable to use temporary structure such as scaffolding for access?  we require an acces platform to allow access for cleaning of effluent ponds. I thought that this could only be a temporary measure only and if access is frequent it should be fixed.  also does anyone have a copy of the ISO standard BS EN ISO 14122 part 2: working platforms and walksways. 

Shady - somewhat shady question for reasons already given.

Is this a SUDS pond?

If so, and if you are in the UK, then the SUDS Manual is your starting point - CIRIA C753, published by the Construction Industry Research and Information Association. There might be a free download on the CIRIA website, but I doubt it.

Some of the principles are online eg. at 

https://www.transport.gov.scot/media/40940/appendix-a136-suds-design-princples.pdf

In principle, such ponds should be largely self-maintaining and become just part of the landscape just the like the one in front of the Queen Elizabeth University Hospital in Glasgow. Deep, so there is a wooden fence all round to stop people falling in, with a couple of locked access gates. Over time it will become a wildlife sanctuary. Nature is very adept and finding safe places to thrive!