Stream Gauging

Stream Gauging

Brailey Hydrologic has installed and operated stream gauges at over 150 locations throughout Alaska. Our services typically include gauge installation, discharge measurements, rating curve development, and streamflow data processing.

 

We use a variety of methods for stage monitoring, including pneumatic, acoustic, radar, and pressure sensors, with and without remote telemetry. Likewise, discharge measurements encompass a variety of techniques. Data processing is accomplished using the Aquarius software following USGS quality assurance protocols.

Index Velocity Gauging

In tidal channels, Brailey Hydrologic uses the Index Velocity Method for continuous monitoring of outgoing and incoming tides. This method uses a stationary acoustic Doppler velocity meter (ADVM) to measure the average velocity perpendicular to flow, which is correlated against channel discharge measured using a boat-mounted acoustic Doppler current profiler (ADCP).

 

The ADVM velocities (termed index velocities) are recorded at 5- to 15-minute intervals and are used together with water level data to calculate time-varying channel discharge. Tidal monitoring using this method requires 120 to 180 calibration measurements recorded at 5- to 7-minute intervals throughout the tide cycle.

 

Brailey Hydrologic’s motorized SonarCat provides an efficient platform recording the discharge measurements, bathymetry, and velocity distributions needed for successful monitoring of tidal discharge.