The Long Throat Flume is used for flows from 5 litres per second for the smallest, to flow rates of over 1000 litres per second.

Small flumes are prefabricated in stainless steel to fit any channel width.  Large flumes may be cast in-situ using prefabricated steel formwork.   All are tailored to meet the required specification.

The flow characteristic is approximated by:
       Q=1.8(b)[h]^1.5
       where Q is flow (m³/s),
                    b is throat width (m) and
                    h is the head (m).