Detail Design of Drainage for New Developments
Cost Effective Design
We aim to produce a 'good design' which minimises the percentage of the site occupied by drainage infrastructure and so maximises the area available for
development. At the same time we need to balance the often conflicting requirements of hydraulic performance, 'buildability', construction cost and the
need for low maintenance to produce an overall cost effective design.
Detail Design Stage
By the completion of the detail design stage, the proposed drainage arrangements for a site would be shown in sufficient detail on drawings, supported by
specifications, that the design could be approved by the relevant body and subsequently constructed on site.
Design of Sewers for Adoption
This covers both foul and surface water sewers for adoption by the water company under a section 104 agreement (Water
Industry Act, 1991).
The design would be carried out to the requirements of 'Sewers for Adoption' (sixth or seventh edition as appropriate) together
with any additional requirements of the adopting
water company. In Wales the national standards for foul sewers would supersede the relevant parts of Sewers for Adoption.
In addition to the design work, we can also undertake or assist in the negotiations with the water company for the preparation of the section 104
adoption agreement itself. We can also either undertake or assist in the negotiations for any sewer diversions (section 185) or
off-site sewer requisitions (section 98).
We use Micro Drainage
software extensively for the hydraulic design of sewerage systems and AutoCAD software for the production of the construction drawings. The drawings would
include 1:500 scale layout plans of the proposed drainage infrastructure together with long-sections showing the gravity sewers and rising mains. Detail drawings
of the associated ancillaries such as manholes, pumping stations, rising mains, outfalls, etc would also be produced.
Design of Sustainable Drainage Systems (SUDS)
Sustainable Drainage Systems (SUDS) incorporate features such as
measures together with conveyance systems where relevant. SUDS are likely to comprise a large part of
the surface water drainage arrangements of a site. See Micro Drainage
Source Control module
page for further details of the software used for the design work.
We can also assist in the preparation of the arrangements for the long-term maintenance of the SUDS features.
Design of Highway Drainage
We can undertake the design of the drainage for new highways subject to adoption under Section 38 agreements together with the drainage element of
work constructed under section 278 agreements.
The work would be carried out in accordance with the DMRB or the requirements of the relevant highway authority.
Design of Drainage for Building Regulations
Drainage not for adoption would generally need to comply with the Building Regulations document 'Approved Document H' or alternative documents.
The mandatory adoption of sewers has been introduced in Wales but this is still pending in England. In Wales this applies to both foul
and surface water sewers but not to SUDS systems which would require approval under Schedule 3 of the Flood and Water Management Act 2010
if and when that schedule is implemented. This means that, in general in Wales, the remit of Building Regulations regarding drainage matters is limited.
The situation in England has not changed recently in this respect.