proposed solar park development at cave farm, nr pitney, somerset ...

Volume of Runoff Caculations
Client: AEE
Engineer: H2OK Consultants
Cave Farm, Nr Pitney,
Location:
Somerset
Site:
Date:
Cave Farm
06/12/2012
SITE INFORMATION
Pre-development total area
Pre-development permeable area
Pre-development impermeable area
Post-development total area
Post-development permeable area
Post-development impermeable area
RAINFALL EVENT INFORMATION
Return period
Whole area greenfield runoff rate inclusive of 20% increase due to climate change (see attached MicroDrainage
calcs (SAAR values multiplied by 1.2))
IoH124 post-development runoff rate inclusive of 20% increase due to climate change (see attached
MicroDrainage calcs (SAAR values multiplied by 1.2))
Duration of rainfall event
Depth of Rainfall (calculated using Wallingford Procedure including 20% increase for climate change)
115000 m²
115000 m²
0 m²
115000 m²
114650 m²
350 m²
100 year
151.3 l/s
151.3 l/s
6 hours
80.04 mm
RUNOFF CALCULATION
Pre-development permeable area runoff
3268080 litres
Pre-development impermeable area runoff
0 litres
Total pre-development runoff
3268.1 m³
Post-development permeable area runoff
3268080 litres
Post-development impermeable area runoff
28014 litres
Total post-development runoff (without mitigation)
3296.1 m³
Difference in runoff 28 m³