The Northwest Branch, located in the eastern part of the County, is
the largest of the County's three contributing watersheds to the Anacostia
(Northwest Branch, Paint Branch, and Little Paint Branch). Land uses
differ greatly from the headwaters downstream to where the Northwest
Branch flows into Prince George's County. Different development patterns
have shaped the watershed, affecting the stream system to different
degrees. Tributaries in the upper part of the watershed, particularly
the headwaters, support the few remaining streams with excellent and
good conditions in the Northwest Branch watershed.
The fish community found in Northwest Branch includes rosyside dace,
northern hogsuckers, and five species of shiners. Although the same
species can be found throughout the watershed, the community composition
varies dramatically in response to habitat, flow, and pollutant stressors.
In the upper reaches, low density land uses are predominant and the
landscape is in a transition from formerly widespread agricultural land
uses to a more suburban landscape. The streams in this area are also
in a transition, from carrying sediment loads and nutrients associated
with past farming activities, to a watershed condition that includes
less widespread land disturbance, but higher imperviousness. As this
area develops and the imperviousness increases, today's environmental
standards will provide forested buffers, floodplain and wetland protection,
and management of stormwater runoff. However, even with application
of modern stormwater controls, some changes in watershed hydrology are
inevitable.
The middle section of the watershed contains a mix of moderate to higher
density land uses along with large areas of forested parkland. Inadequate
stream buffers on the tributaries and altered hydrology are common in
this section. More of this area developed with stormwater controls than
in the lower reaches; however, in many areas the stormwater management
technologies used are not as effective as methods used today. Bel Pre
Creek contains many such older controls, and is a focus of efforts underway
to identify areas for improvements in runoff controls and stream channel
restoration. The Rolling Stone tributary is the site of a relatively
new stormwater retrofit project that has been successful in improving
runoff controls in a previously developed area, modifying and updating
structure performance and enhancing pond appearance.
The lower reaches of Northwest Branch contain older and more concentrated
development, where communities developed long before requirements for
stream valley protection or stormwater management. The hydrology in these
areas has been significantly altered and the stream condition is generally
poor or fair. However, also to be found in this part of the watershed
is a stream section described as "the most scenic and rugged section
of the Anacostia watershed". This is the beginning of the torrent
and gorge section of the Northwest Branch that begins just below Route
29. This is a transitional area where the Northwest Branch leaves the
Piedmont and passes through the fall line before entering the slower reaches
of the Coastal Plain. This area contributed significantly to the state
of Maryland identifying the Anacostia as a state "Scenic and Wild
River" in 1984, under the Maryland Scenic and Wild Rivers Act.
Northwest Branch Stream Condition,
Habitat Conditions and Management Category Designation
| Subwatershed/ Stream Condition |
Habitat Condition |
Primary Factors Affecting Stream Condition |
Unique Characteristics and Management Category
Designation |
| Sandy Spring Trib.
GOOD (Preliminary) |
GOOD (Preliminary) |
Problems with bank stability, sediment deposition
and embeddedness are causing habitat impairment. |
Watershed Protection Area - remedial |
| Upper Main -Upper Left Fork
FAIR |
FAIR |
Problems with bank stability, sediment deposition
and embeddedness are causing habitat impairment. |
Watershed Restoration
Area |
| Upper Mainstem - Lower Left
Fork
GOOD |
GOOD |
Sediment deposition and bank erosion adversely
affecting habitat. |
The Sandy Spring for which the area is named is
located in this subwatershed. Watershed
Protection Area - remedial level |
| Old Orchard Trib.
EXCELLENT |
GOOD |
Tributary is very shallow, limiting fish habitat,
but has excellent benthic habitat. Some sediment deposition and
bank erosion is occurring due to highly erodible soils. |
Watershed Protection Area -
special and remedial |
| Bryants Nursery Trib.
EXCELLENT |
GOOD Overall |
Bank stability and sediment deposition problems
observed. |
Impacts related to previous agricultural use have
created areas of channel instability which may make this tributary
more sensitive to changes in hydrology. Watershed
Protection Area - special and remedial |
| Bachelors Forest Trib.
GOOD |
GOOD Overall |
Bank stability, sediment deposition and embeddedness
problems observed. Inadequate riparian buffer is limiting factor. |
Watershed
Protection Area - remedial |
| E. Bachelors Forest FAIR
(Preliminary) |
GOOD (Preliminary) |
Problems with bank stability, sediment deposition
and embeddedness are causing habitat impairment. |
Watershed Restoration Area |
| Rolling Stone Trib. GOOD |
FAIR Overall Fish
habitat poor |
Tributary contains a highly erodible sand substrate
which affects all habitat parameters, particularly fish habitat.
Benthic community is rated excellent |
Watershed
Protection Area - remedial Level |
| Upper Mainstem EXCELLENT |
GOOD |
Condition is on margin of good rating - problems
include embeddedness, sed. deposition, and bank stability. Substrate
is sandy and unstable. |
Watershed
Protection Area - special |
| Upper Main B |
no current data |
|
|
| NWBr GC/Norwood Trib. |
no current data |
|
|
| Longmeade Trib.
POOR (preliminary) |
GOOD (Preliminary) |
Problems with bank stability, sediment deposition
and embeddedness are causing habitat impairment. |
Watershed Restoration Area |
| Bel Pre Creek - POOR |
FAIR to GOOD Overall |
Habitat indicates flow related problems including
marginal bank stability, sediment deposition, and embeddedness. |
Watershed
Restoration Area |
| Middle Mainstem Glenmont - FAIR |
FAIR Overall |
Bank stability is fair to poor at most stations
and the amount of sandy bedload material is affecting habitat for
both fish and macroinvertebrates. |
Watershed
Restoration Area |
| Wheaton Park Trib. - FAIR |
GOOD |
Some embeddedness and deposition occurring.
Upstream pond is influencing aquatic community. |
Section between Brookside Nature Center and Kemp
Mill Rd. in good condition. Watershed
Restoration Area |
| Middle Mainstem - Colesville
- FAIR |
GOOD Overall |
Problems with bank stability, embeddedness, deposition
are affecting fish and benthic habitat. |
Watershed Restoration
Area |
| Lamberton Dr. Trib. - POOR |
FAIR |
High imperviousness and uncontrolled runoff has
severely affected habitat for both fish and macroinvertebrate communities.
Poor bank stability. |
Within memory of some residents, stream has downcut
from a small "step over" stream to one with 12' banks.
Watershed Restoration Area |
| Lockridge Dr. Trib. - POOR |
FAIR |
High imperviousness and uncontrolled runoff has
severely affected habitat. Poor bank stability. |
A very steep gradient and channel downcutting
has exposed a bottom substrate that now consists of primarily bedrock
and unstable depositional material. Urban
Stream Management Area |
| Lower Mainstem - FAIR |
GOOD Overall |
Epifaunal substrate and fish cover improve in
this section. |
This section includes the beginning of the "torrent
and gorge" area of the Northwest Branch and has been identified
as the "most scenic and rugged section of the Anacostia watershed".
Watershed Restoration Area |
The Northwest Branch Watershed
Management Categories
A study is currently underway as part of the Anacostia Restoration
Project, Phase II to examine opportunities throughout Northwest Branch
for stormwater retrofit and stream restoration projects. This study
is being conducted cooperatively by the MCDEP, M-NCPPC and the Army
Corps of Engineers Baltimore District. A comprehensive watershed restoration
action plan will result from this study. The management strategy outlined
below is generally consistent with preliminary assessments in the study.
It will be refined as the study progresses.
Watershed Protection Areas
These areas include the Lower Left Fork of the Upper Mainstem, the
Sandy Spring tributary, the Upper Mainstem, Old Orchard tributary, Bryants
Nursery tributary, Batchellor's Forest tributary, and the Rolling Stone
tributary.
Special level of protection
Three subwatersheds with excellent stream conditions are placed in
this category - Old Orchard tributary, Bryants Nursery tributary and
Upper Mainstem. Due to existing and planned land uses, these three subwatersheds
are not "preserved" in such a way that conditions are expected
to remain excellent without some level of management to protect the
resource from anticipated. The level of new development anticipated
will increase imperviousness requiring special management tools to ensure
that the stream conditions remain in the excellent range. Despite relatively
low existing levels of imperviousness, these areas are experiencing
erosion and stream bank instability problems that are believed to be
associated with past clearing activities and land uses, as well as the
erodibility of the soils. Bank instability and sediment deposition
problems are pronounced in the Old Orchard tributary and Bryants Nursery
tributary, and these two subwatersheds are identified as needing remedial
protection tools as well as a special level of protection.
| Watershed Management Strategy |
- Continue current efforts to closely monitor and apply state of the
art BMPs to new development projects.
- Develop and implement targeted public education program for residents,
businesses and developers about the high quality stream resources and
special subwatershed management needs.
Remedial level of protection
Remedial protection tools are recommended for much of the headwaters
of Northwest Branch, including Batchellors Forest tributary, the Lower
Left Fork, Sandy Spring tributary, Old Orchard tributary, Bryants Nursery
tributary, and Upper Main B, NWBr GC/Norwood tributary, and Rolling
Stone tributary. The stream channels in these areas of the upper reaches
of Northwest Branch, despite excellent and good biological community
conditions, have been destabilized by past erosion and accelerated downcutting
associated with land clearing activities without adequate best management
practices, particularly the use of forested buffers. Many areas in these
headwaters also have erodible soils that tend to make channels more
susceptible to accelerated downcutting. These areas that have a combination
of erodible soils and poor or marginal bank stability will benefit greatly
from remedial efforts to re-stabilize channel morphology and facilitate
the system's return to a stable condition.
| Watershed Management Strategy |
- Identify and implement stream restoration and habitat improvement
projects in conjunction with the Northwest Branch Watershed restoration
effort and Action Plan currently underway.
- Provide targeted public education for residents, businesses and
developers about the subwatershed resources and stewardship opportunities.
Watershed Restoration Areas
The Northwest Branch mainstem and tributaries from the Northwest Branch
Golf Course downstream are designated restoration areas, with the exception
of the the Rolling Stone tributary. In much of the area within this
category, imperviousness levels are already high and are not expected
to increase greatly. Highly impervious land uses occur throughout much
of the lower watershed and stream conditions have been widely affected
by uncontrolled runoff. Several of these subwatershed, particularly
Bel Pre Creek have stormwater management controls which predate our
current methods and therefore are frequently less effective.
The Lockridge Dr. subwatershed has been extensively piped and channelized,
and where the stream re-emerges into a natural channel, extreme downcutting
has occurred, in places to the bedrock. No opportunities exist to substantively
improve the quantity of stormwater runoff in this subwatershed, however,
small incremental improvements may be achieved through voluntary actions
to slow runoff from yards and roof-drains. A stream restoration project
is planned to stabilize the channel and guard against continued degradation.
Efforts targeted at controlling non-point source pollutants, such as
nutrient control from yards and pet waste, and small voluntary improvements
to control yard runoff will help to improve runoff quality from this
subwatershed.
| Watershed Management Strategy |
- Identify and implement stormwater retrofit, stream restoration and
habitat improvement projects in conjunction with the Northwest Branch
watershed restoration effort currently underway.
- Develop Northwest Branch Watershed Restoration Action Plan to implement
stormwater retrofit and stream restoration projects and comprehensive
watershed education and stewardship program.
Land Cover Graph |

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