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P1-714, P2-714 Roughness Coefficient (Ks) 
When P1-700, P2-700 = 2, BS3680 Flume this parameter is used to enter the 
roughness coefficient of the flume in millimetres, see table below for 
further details. 
Plastics, etc                         
Perspex, PVC or other smooth faced 
plastics 
Resin-bonded glass-fibre moulded 
against smooth forms of sheet metal or 
well sanded and painted timber 
Metal                            
Smooth, machined and polished metal 
Uncoated sheet metal, rust free 
Painted or coated casting 
Concrete                         
In-situ or precast construction using 
steel formwork, with all irregularities 
rubbed down or filled in 
In-situ or precast construction using 
plywood or wrought timber 
framework 
Smooth trowelled cement rendering 
Concrete with thin film ofsewage 
slime 
Wood                              
Planned timber or plywood 
 
P1-715, P2-715 Water Temperature 
When P1-700, P2-700 = 2, BS3680 Flume this parameter is used to enter the 
mean water temperature in 
0
C.