The United States Geological Survey maintains three river gauges in and around the Big South Fork National River and  Recreation Area. 

Leatherwood Ford gauge is located at the Leatherwood Ford Day Use Area off Highway 297.  Most river descriptions are based on flow readings from this location.

Clear Fork gauge is located on the Clear Fork River just below Burnt Mill Bridge.  The Clear Fork River is a major tributary to the Big South Fork and changes in flow rates here will affect the Big South Fork River.

New River gauge is located just outside the Big South Fork boundaries on the New River just below the Highway 27 bridge.  New River is a major tributary to the Big South Fork and changes in flow rates here will affect the Big South Fork River.