Hillingdon SuDS Design & Evaluation Guide

Concept Design
Checklist for Concept Design Stage
Design Check
Requirement
1. Data gathering
Information to understand site To understand site constraints that inform Concept
constraints including geology, Design
topography, flood risk, utilities,
landscape context, community and
wildlife
Planning requirements that influence To be aware of planning constraints that impact
SuDS design
SuDS design
2. Flow route analysis
Existing flow routes
Modified flow routes
To understand site hydrology
To understand the impact of development
55
3. General SuDS design elements
Collection of runoff
Source control
Conveyance
Management train
Sub-catchments
Storage
Flow control
Outfall
Runoff retained at or near the surface
Primary treatment stage to protect the
development
At or near the surface
SuDS components in series to manage quantity
and quality
Dividing development into discreet SuDS entities
Indicate extent and location where runoff is stored
Location to demonstrate storage location
Locations and method of discharge
4. Quantity
Confirm interception losses will
occur
Confirm how rate of flow from
development will be reduced to
greenfield runoff rates
Confirm how runoff will be managed
to greenfield runoff volumes
Confirm climate change allowance
and whether urban creep is applied
Confirm ‘long term storage’
Demonstrate the use of SuDS components that
provide interception losses
Demonstrate flow rates are achievable. Increase in
allowable discharge rates e.g. brownfield sites only
in agreement with LPA/LLFA
Demonstrate whether Approach 1 or Approach 2
will be used to manage volumes
Demonstrate additional volumes to be managed
Demonstrate no increase in runoff from predevelopment
status
London Borough of Hillingdon SuDS D & E Guide
© 2018 McCloy Consulting & Robert Bray Associates