Scottish Water is hoping to have all ‘Section 7’ agreements for SUDs schemes completed by June 2016. This means that across Scotland all councils will be maintaining the above ground, and above the water line, part of a SUDs scheme. Scottish Water will be maintaining the below ground pipes and de-silting ponds etc.
Although the Section 7 agreement is with the Roads department, they may contract that work out internally (ie parks department) for the landscape maintenance. Once this way of working is adopted it is suggested that there is a landscape maintenance scheme for every SUDs scheme that is approved. This should be separate to the landscape maintenance scheme for the whole site.
The majority of SUDs schemes are intended to be vested (taken over) by Scottish Water. They will now be vesting the schemes at a much earlier stage and holding back monies from the developer until they are completed to their standards. Scottish Water have previously accepted ( 1:4) slopes but these are unlikely to be acceptable to Edinburgh’s parks department / road maintenance as they do not have the grass cutting machines to support such steep slopes. This will mean other design solutions, such as planting the banks or shallower slopes.
Land take may have to be increased. Underground solutions are not the answer and only to be used in exceptional circumstances on restrained urban sites. See advice from the local authority to establish their standards. CIRIA have launched a new SUDs manual (C753) on the 12th November. SEPA are updating their SUDS advice (RM08) to align with the CIRIA Manual which will be implemented on new designs from 31 May 2016. The key change is the way water treatment is worked out. Gone are the ‘treatment level one and two etc’. Instead there is a new system. It is based on pollution indices for the land use and offsetting them with an equivalent or greater indices for the different SUDS used, taking account traffic movements expected. It is unlikely to alter the land take required on schemes. The exception will be for water courses discharging into very sensitive environments for example SSSI’s.
The updated Water and Drainage Assessment Guide is near completion and should be launched on Sepa’s website by the end of this year. This replaces the Drainage Assessment guide and has details on roles and responsibilities and standards. The Water and Drainage PAN‘s that were being updated have now stalled, indefinitely, due to lack of resource. Scottish Government has instead posted a Q and A on their website. There has been discussion surrounding Building Standards and SUDs.
In curtilage is under the remit of Building Standards and they are guided by the CIRIA SUDS Manual (not Sewers for Scotland), but anything beyond the curtilage boundary is not in the remit of Building Standards. Sewers for Scotland 3 has been launched and is available to download from SW’s website. Scottish Water has already procured a contract to incorporate additional SUDs elements (filter trenches and swales) so that it accords with the new CIRIA manual. This revised edition of Sewers for Scotland will be consulted upon next year.
Scottish Water’s policy is that no surface water should be discharged to their combined sewers unless in exceptional circumstances. They have undertaken an internal review on its application and consistency and have introduced internal training and escalation route that will lead to a more robust application. Extensive justification that surface water cannot be retained on site or discharged elsewhere (ie culvert, surface water sewer, watercourse or canal) will need to be provided with costs . This will start to affect planning applications now. Julie Waldron, Nov 2015