Design, supply and installation of low-flow environmental impacts monitoring system on the River Yeo in Somerset, 2005-2008
Wessex Water contracted HL to install a new flow-gauge to provide flow data on the environmental impact of abstraction upstream and downstream of a riverside borehole for public-supply.
Due to the channel and hydraulic conditions at the site on the River Yeo in Somerset, HL selected a horizontal ADCP Channelmaster device from Teledyne RDi for providing accurate velocity profiles at one elevation at a convenient section under a footbridge, so that a velocity index rating could be established.
The purpose of the investigation was to produce accurate flow records during an extended pumping-test period. The period tested covered a very-low flow period at the end of 2006, with the aim of evaluating net-gain/losses along a 3km reach upstream and downstream of the riverside borehole source.
The work included gauging method feasibility, design, installation management and commissioning with a sequence of current-meter gauging methods used to produce a calibration gauge using the index-velocity rating method. This permanent gauge was supported by a current-meter gauging programme at intervals along the 3km reach of the River Yeo.
H-ADCP Flow Gauge, Wessex Water case study