Pit Database Width help required

[Francis Lane 0]

Hi,

Could someone please help me understand the width column in the pit inlet database.

As I understand it. TUFLOW uses this information to extrapolate beyond the depth/flow curve (Section 4.5.1.2 of the TF manual).

If we are modelling a kerb inlet pit (lintel only) would the width be the effective perimeter of the lintel opening?

and if modelling a surface grate, would the width be the effective perimeter of the grate?

 

Or alternately do we need to work backwards with an orifice calc to determine the width that gives the same flow at the top of the curve?

Regards,

Francis