Gulf Branch


Gulf Branch is located in north Arlington.

Drainage Area

Gulf Branch drains directly into the Potomac River.

Gulf Branch Sampling Site Map(JPEG, 3MB)
Drainage area for the Gulf Branch stream monitoring site.

Rapid Stream Assessment Technique Scale: Good

In 2011, we assessed all the streams in the County as part of the Stormwater Master Plan Update. The assessment used the Channel Evolution Model to evaluate which sections of the streams are actively eroding to prioritize them for stream restoration. During that assessment, Gulf Branch was evaluated to be a priority stream for stream restoration given that approximately 45 percent of the stream length assessed was found to be in an actively eroding state. In addition, only about 30 percent of the stream channel has been stabilized.

About Gulf Branch

In 2011, a watershed retrofit study of the Gulf Branch subwatershedwas completed. In 2019, the design process for Gulf Branch restoration was begun, with ongoing opportunities for public input. Learn more about the Gulf Branch restoration and provide your feedback

Macroinvertebrate Monitoring Data

The stream monitoring site is located just downstream of Military Road and the Gulf Branch Nature Center.

Macroinvertebrates commonly found are:

  • Black flies
  • Flatworms
  • Midges
  • Net-spinning caddisflies
  • Small minnow mayflies

In fall 2011 and spring 2012, we contracted a professional monitoring group to collect family/genus-level macroinvertebrate and fish data at each of our volunteer monitoring sites.

Gulf Branch Stream Monitors
Collecting macroinvertebrates is a two-man job. One person rubs the rocks and disturbs the sediment so the macroinvertebrates are washed into the net. The other person holds the net.

Gulf Branch Macro Graph(JPEG, 197KB)
Click on the graph above for an enlarged version

Bacteria Monitoring Data

There is one bacteria monitoring site on Gulf Branch located just downstream of Military Road and Gulf Branch Nature Center. Learn more about bacteria monitoring data.