Long Branch at Olley Lane near Fairfax, VA Water Level Today

NWS river forecast

Forecast from the NOAA National Water Prediction Service. Issued a few times a day and only while a forecast is active. Not for navigation.

Last 30 days

About this gauge

USGS gauge 01654107 sits on Long Branch and reads everything draining 1.2 square miles of the Middle Potomac-Anacostia-Occoquan basin. Its datum sits 294 feet above sea level NAVD88. Daily flow has been on record here since 2023, 4 years of it.

Where this gauge sits in the drainage

No gauged site sits above this one on the mainstem, so this is the first published reading on the river. Downstream the next reading comes from Long Branch near Annandale, VA at 3.7 square miles, so what passes this gauge is about 32% of the water measured there. Water passing here goes on to Accotink Creek at Keene Mill Rd at Springfield, VA. It then enters Accotink Creek below Lake Accotink, VA, below which releases set the flow.

Normal flows here

Long Branch runs a median of 0.4 cfs at this gauge across 4 years of record. February is the fullest month at a median 0.7 cfs, and September the leanest at 0.1 cfs. The highest daily mean on record is 40 cfs in 2024, and the lowest is 0.0 cfs in 2025.

Medians from the USGS daily-statistics record, 2023 to 2026. A month at 100% is running at its own long-term median.