If your development is located within Flood Zone 1 and falls into either of the categories it will require a SUDS Drainage Design.
• 10+ dwellings / over half a hectare / building(s) exceeds 1000m²
• Office / light industrial - 1000+ m² / 1+ hectare
• General industrial - 1000+ m² / 1+ hectare
• Retail - 1000+ m²/ 1+ hectare
• Gypsy/traveller site - 10+ pitches
• Site area exceeds 1 hectare
Firstly, it must be determined if surface water flows can be disposed of via infiltration (soakaways), failing this flow should be directed to watercourse, only in the event that infiltration is not suitable and there are no available watercourses will a connection to the public sewer be authorised.
Ideally all flows as a result of the development should discharge to ground incorporating SUDS where possible, however this is not always achievable, dependant and a number of different restraints.
To reduce the time of concentration and offset the additional volume into either the watercourse or public sewer attenuation (storage) is generally required.
Attenuation can comprise of a number of different SUDS structures such as: Ponds, Detention Basins, Bio-Retention Areas, Swales, Permeable Paving and Geo-cellular Storage to name a few. Dependant on the location of the development, each Lead Local Flood Authority have their own preference and guidance as to which structures are preferable.
We undertake consultation with all the Statutory Authorities when developing our SUDS designs, which are developed in accordance with Building Regulations and CIRIA SUDS Manual. All of our drainage designs are modelled using industry recognised software.
*Detailed Planning Applications will require a more in-depth appraisal compared to Outline Planning Applications.
Click the link below for an explanation of diffrent types of SUDS componants: