Blue Spotlight On: The Muddy Branch Watershed

September 6, 2018
  |   1 Comment

DEP’s Blue Spotlight On series is a new feature for residents to learn about the County’s local watersheds.This is the second blog in the Blue Spotlight On series (check out our spotlight on the Anacostia River).  Today’s highlighted watershed: Muddy Branch!


About Muddy Branch

The Muddy Branch watershed is one of the smaller watersheds in Montgomery County, covering 20 square miles or approximately 4% of the County. It begins its meandering course in Gaithersburg and flows in a southwesterly direction to its confluence with the Potomac River near Pennyfield Lock on the C&O Canal.

Numerous unnamed tributaries extend into areas of the watershed around Quince Orchard, Kentlands, North Potomac and Darnestown, collecting water that either runs off quickly during storms or seeps slowly through soil, eventually flowing into tributaries to maintain baseflow during dry periods.

Muddy Branch Map



Development patterns play an important role in the quality and quantity of water flowing into Muddy Branch, and ultimately the Potomac River and Chesapeake Bay.

In the Muddy Branch Watershed, development is most dense in the Gaithersburg / I-270 area, and it becomes progressively less dense downstream to the Potomac River. Stream condition, as rated by the County’s biological monitoring program, is Fair to Poor in the upper portions of the watershed and Good in the lower portions of the watershed. This means that there is a greater diversity of wildlife downstream, and that the wildlife upstream can tolerate the impaired stream conditions.


Restoration Highlights

To help mitigate the impacts of development, the County is currently constructing 4 restoration projects in the Muddy Branch watershed, including:


Potomac Ridge Stormwater Pond Retrofit Project

Potomac Ridge Stormwater Pond Retrofit Project –  The first flush of stormwater runoff enters this recently completed facility and soaks into two linear stone filled infiltration cells (seen above).  During larger storm events water collects in the detention pond at the end of the infiltration cells.


Potomac Ridge Stormwater Pond Retrofit Project

Potomac Ridge Stormwater Pond Retrofit Project – Detention pond and new riser structure is seen downstream of the infiltration cells.


Potomac Chase Stormwater Pond Retrofit Project

Potomac Chase Stormwater Pond Retrofit Project – the newly graded pond still needs grass cover planted on the side slopes, wetland plants around the pond edge and a total of 518 trees and shrubs will soon be planted around the pond, created a dense, healthy ecosystem.


Flints Grove Pond

Flints Grove Pond – Currently a dry pond, will become a wet pond with an average water depth of 5 feet when construction is completed in fall of 2019.  Wet ponds are more effective than dry ponds at removing pollution and sediment from stormwater runoff, leading to better water quality.


Flints Grove Stream Restoration

Flints Grove Stream Restoration – A 1,200 foot long section of the stream immediately upstream of the Flints Grove Pond which is actively eroding, as shown in the photo above, will be stabilized to reduce the amount of sediment entering the pond.  The restoration will greatly reduce erosion and improve the stream health.


Recreational Opportunities

There are many recreational opportunities in the Muddy Branch Watershed. Much of the Muddy Branch stream in Gaithersburg is in city parks, including Morris Park and Malcolm King Park.

At the point where Muddy Branch flows under Route 28, it leaves the City of Gaithersburg and enters parkland maintained by Montgomery County Parks. The Muddy Branch Greenway Trail, a 9- mile natural surface trail, begins at Route 28 and follows the Muddy Branch to its confluence with the Potomac River.


Muddy Branch Greenway Trail

Muddy Branch Greenway Trail – A 9-mile natural surface trail that traverses up and down the Muddy Branch stream valley walls from Route 28 in North Potomac to Pennyfield Lock on the C&O Canal.


Other areas to access the Muddy Branch Watershed are Blockhouse Point Conservation Park and Pennyfield Lock Conservation Area.

If you would like to volunteer in the Muddy Branch Watershed, join the Muddy Branch Alliance or become a Montgomery County Stream Steward.


Muddy Branch

Muddy Branch makes its grand exit from Montgomery County through this aqueduct under the C&O Canal just before flowing into the Potomac River. Many canoe and kayak paddlers use the boat ramp at Pennyfield Lock to put-in the Muddy Branch and paddle through the aqueduct to access the Potomac River.

One comment on "Blue Spotlight On: The Muddy Branch Watershed"

  1. Paul Hlavinka says:

    The Muddy Branch trail has actually been extended two miles into the City of Gaithersburg.

Leave a Reply

Your email address will not be published. Required fields are marked *