Hydrometrics

Bathymetric Data Collection

Brailey Hydrologic can provide high-resolution bathymetric data across Alaska, delivering accurate channel and waterbody mapping to support hydraulic modeling, aquatic studies, and infrastructure design.

 

Our capabilities include GPS-integrated sonar systems, ADCP-based depth and velocity measurements, and field data collection in rivers, lakes, and coastal environments.  We combine precise positioning with rigorous data processing to produce reliable bathymetric data and cross sections suitable for engineering analysis and regulatory applications.

Velocity Mapping

Brailey Hydrologic can collect velocity data and provide velocity maps for use in hydraulic model calibration, index velocity gauging, and sonar equipment deployment.

Acoustic Doppler Discharge Measurements

Brailey Hydrologic has performed over 1,750 acoustic doppler current profiler (ADCP) measurements on flows as large as 1.5 million cfs.

 

Dave Brailey is the developer of the SonarCat, a lightweight survey vessel for measuring discharge, bathymetry, and velocity mapping on swiftwater streams. The SonarCat features a forward instrument mount that creates downpressure with increasing flow resistance. In contrast with tethered ADCPs, this geometry maintains acoustic contact at high flow velocities.

 

The SonarCat’s light weight and shallow draft allows flow measurement in depths as small as 1 foot, and it can be readily transported in small planes, small helicopters or via commercial air cargo. On smaller streams, Brailey Hydrologic uses tethered ADCPs deployed using temporary pulley systems.

Dye Dilution Discharge Measurements

Brailey Hydrologic has more than 15 years of experience using fluorescent dye dilution techniques to measure streamflow in steep, turbulent channels where conventional current meters and hydroacoustic methods are often impractical.

 

In well-mixed, non-turbid streams, this technique provides rapid, repeatable discharge measurements with higher precision than many traditional methods and can be used year-round, including under ice without extensive drilling. 

 

The fluorescent dye used for these measurements is non-toxic and environmentally safe when applied at appropriate concentrations. The same class of fluorescent tracers is widely used in medical diagnostics, including angiography to visualize blood vessels, ophthalmology to detect corneal abrasions, and in biomedical research to image brain structures.