June 25, 2018: Walked upstream along Hatmark Branch from its junction with Accotink Creek in Fairfax City's Thaiss Park to its last open water upstream on the campus of Oakton High School
Hatmark Branch is one of the lesser tributaries of Accotink Creek. It is not officially named by the U.S. Geological Survey, and goes unnamed on many maps. However, it is clearly named on many Fairfax County planning maps.
At its junction with Accotink Creek, Hatmark Branch runs parallel and very near to Pickett Road. It has been straightened here to accommodate the road and its bed reinforced with a layer of large stones. This leaves the stream uniformly shallow and lacking deeper pools, which may account for the scarcity of fish in this portion. Damselflies are common here. Opposite Pickett Road, to the east of Hatmark Branch Eakin Park extends eastward into Fairfax County, providing an extensive natural buffer.
Invasive plant species are not so severe in the Eakin Park section, but the narrow strip between Hatmark Branch and Pickett Road hosts extensive growth of invasives such as Bush Honeysuckle, Multiflora Rose, Chinese Wisteria, and Porcelainberry. This is even more so nearer Route 50, where there are fewer trees and the vines clos in from both sides.
Just south of Route 50, a short section of Hatmark Branch flows through a mostly wooded property owned by Fairfax Water where a pumping station is located. North of Route 50 Hatmark Branch flows through Fairfax County.
The culvert passing under Route 50 includes a four-foot drop, posing an impassible barrier for any fish trying to move upstream. Above Route 50 is a head-scratching situation, as the stream is nowhere to be seen, just a muddy channel. It appears that Hatmark Branch suffers the indignity of being forced into storm drains at Lee Hwy, then traveling in pitch black darkness for a quarter-mile to the south side of Route 50.
The first section of Hatmark Branch above Route 50 is in Towers Park, then in a privately-owned narrow strip squeezed between Circle Towers Apartments, Blake Lane, and a restaurant parking lot. The channel does receive some water off the neighboring properties, but more resembles a marsh than a stream, with intermittent puddles and only the faintest trace of a flow. A cleared strip for a gas line runs through the channel, contributing to the marsh effect.
Above Lee Hwy, Hatmark Branch is a stream again, flowing more naturally with sinuous turns. Fish are more plentiful here. Trash is also quite prevalent just above Lee Hwy, but less so farther upstream. There is mostly good buffer on both sides here, but narrower in some points on the west, as Hatmark Branch threads its way between East Blake Lane Park and private properties belonging to an office park and townhouse communities. The East Blake Lane Park trail runs alongside much of the length of the park. The gas line continues here, with a cleared strip following the stream. The streambed is mostly muddy here, rather unusual for streams outside the Tidewater area.
A connector trail crosses a footbridge over Hatmark Branch at Lindenbrook Street. Upstream from this point the streambed is less muddy, with the gravel and stone substrate we more typically see. Further upstream, nearing I-66, buffer becomes narrower on the west, and some houses along Sayre Road have mowed to the bank. There are carpets of the invasive ground cover Periwinkle here, and more prevalence of invasives in general, including much Bush Honeysuckle.
Above I-66, Hatmark Branch consists of two smaller branches which meet in the storm drain passing under I-66.
The western upper branch originates in the storm drains of Oakton High School, but passes aboveground in the fairly spacious wooded southeast corner of the campus. There do not seem to be any fish in this branch. The lower section of this branch has been straightened, with rock reinforcement of the streambed.
The eastern upper branch flows through the property of two townhouse communities. Below Country Spring Road, there is little buffer on the west, but buffer is pretty good on the east between the stream and I-66. The streambed here has been reinforced with rocks. Fish are present, but seem to be in low numbers. Above Country Spring Road, as far upstream as the last open water at Sutton Road, the eastern upper branch is confined to a concrete channel, with only spotty buffer and mowing to the banks in most places. Surprisingly, in a section of broken concrete, there are potholes that support a tenacious population of small fish and freshwater snails.
Share your own observations/comments on this or other sections of the Accotink Creek watershed.
Click on underlined links below|
for the walk in that section.
1 Northwestern Watershed
2 Daniels Run
3 Hunters Branch
4 Bear Branch
5 Long Branch North
6 Main Stem - Pickett Rd downstream to Prosperity Ave
7 Main Stem - Prosperity Ave to Little River Turnpike
8 Crook Branch
9 Coon Branch
10 Turkey Run
11 Long Branch Central
12 Wakefield Park (Main Stem - Little River Turnpike to Braddock Road)
13 Lake Accotink Park (Main Stem - Braddock Road to Old Keene Mill Road )
14 Main Stem - Old Keene Mill Road to Ft. Belvoir Engineering Proving Ground
15 Main Stem - Ft Belvoir Engineering Proving Ground
16 Main Stem - Ft Belvoir Engineering Proving Ground to Telegraph Road
17 Long Branch South
18 Main Stem - Telegraph Road to Potomac River
19 Flag Run
20 Calamo Branch
21 Field Lark Branch
22 Mason Run
23 Kernan Run
24 Hatmark Branch