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Breewood Tributary Restoration

 

In 2009, Montgomery County selected the Breewood Tributary for watershed restoration to meet MS4 Permit requirements .  A comprehensive biological and water quality study shows that past development had degraded the tributary.  Development dating back to the 1950's did not include stormwater management practices commonly used today.   Over the years, the uncontrolled storm flows have resulted in erosion, pollution and poor water quality and wildlife habitat.

Montgomery County, in partnership with the community, has launched a multi-year restoration initiative to implement a series of projects to reverse the damage to the stream and improve water quality.  

 

 

Where is the Breewood Tributary?

The Breewood Tributary is located in the southeastern portion of the County near Wheaton.  It flows into Sligo Creek which is a tributary of the Anacostia River.  The Breewood Tributary drains 63 acres of highly developed urban area.  Most of the area is single family homes, but there are also apartment buildings, town houses, schools, etc.

 

Breewood watershed map

 

 

What Environmental Problems Exist at the Breewood Tributary?

The Breewood Tributary receives the most of its flow from four storm drains that convey stormwater runoff from University Boulevard, Breewood Road, Tenbrook Drive and the surrounding areas. Much of the runoff from these storm drains has no stormwater management, except for the outfall that drains from Northwood High School.

Because of this, Breewood has:

  • eroding stream banks;
  • exposed sewer lines;
  • a large amount of untreated impervious area;
  • land uses associated with fertilizer and pesticide use; and
  • fish blockages.

 

Outflow from a storm drain near University Boulevard
An outfall from University Boulevard that flows into the Breewood Tributary

Consequently, the tributary experiences frequent high flow rates during storms that continue to erode the stream channel resulting in high amounts of sediment washing out of the Breewood Tributary and impacting stream condition downstream in Sligo Creek.   

 

What is the County Doing in the Breewood Tributary?

To fix the problems in the Breewood tributary, the County has implemented a variety of restoration techniques in partnership with residents living in the watershed. The goal of this effort is to restore the Breewood tributary to the “maximum extent practicable” – to make the stream as healthy as possible and help improve stream conditions in Sligo Creek.    

The following restoration techniques are being used:

  • Stream restoration:  Completed in May 2015, the stream channel was reconstructed to reduce erosion and improve habitat for aquatic life.  Additionally, trees, shrubs and meadow grasses were planted along the Breewood Tributary to further improve environmental conditions.
  • Breewood Manor Neighborhood Green Streets:  Completed in October 2014, vegetated best management practices were installed within the public right of way along streets and roads to improve and to reduce stormwater runoff flowing into the Breewood Tributary.
    • Bioretention: Structure at the end of Breewood Road that temporarily traps stormwater to slow it down and remove pollutants was completed in May 2017.
    • Roadside best management practices:  Structures that capture and treat stormwater from roads in the Breewood Manor Neighborhood were completed in October 2014.
  • Parking lot runoff best management practices:  Installing structures to capture and treat stormwater from parking lots at University Towers and Northwood Presbyterian Church.
  • RainScapes Neighborhood:  Working with property owners in the Breewood Manor Neighborhood to install small structures to control stormwater runoff from individual properties and promote groundwater recharge. RainScapes Projects have been installed on three residential properties to date.
  • Community Outreach: Getting local residents involved in reducing their impacts to the stream.
  • Monitoring: Measuring how conditions change in the stream as projects are implemented and how much improvement is made.

 

This effort is part of Montgomery County’s ongoing commitment to improving stream conditions throughout the County and to satisfy regulatory requirements in the Municipal Separate Storm Sewer System (MS4) permit.   

 

Monitoring at Breewood

Stream flow and water chemistry data are being collected at two locations. 

  • The instream station is located close to where the Breewood Tributary enters Sligo Creek. Data from the 62.9 acres that drain to this location reflect all activity in the watershed.  

  • The outfall station is located upstream, slightly below University Boulevard. Data from the 16.9 acres draining to the upstream station provide information on the impacts of about 200 yards of University Boulevard, the University Towers condominiums and two smaller multi-family residential properties at the head of the tributary.  

At these two sites, stream water level is recorded continuously by automated flow monitoring equipment. During some storms, a series of water samples are collected by automated equipment and analyzed in a laboratory for nutrients, heavy metals and other pollutants. Samples are also regularly collected by hand during baseflow (i.e. dry weather) conditions at these locations.  

 

Map of the Breewood monitoring stations

 

Data collected since 2009 show moderate levels of nutrients in the stream and low levels of heavy metals. It is anticipated that these nutrient levels will drop following restoration. If the volume of stormwater moved by the stream decreases as intended, the amount of pollutants that flow into Sligo Creek from the Breewood Tributary would be reduced, even if nutrient concentrations are not greatly decreased.

In addition to these two sites, DEP is collecting flow volume and  water chemistry data from runoff at the end of Breewood Road.  A large bioretention is planned for this location as well as numerous small -scale practices throughout the neighborhood as part of the watershed restoration effort.  Pre- and post-restoration data collected at this station will be compared to evaluate the effectiveness of these small scale neighborhood stormwater management facilities.

 

Pre-Restoration Monitoring

Results from the pre-restoration monitoring show that the stream is strongly affected by the large amount of uncontrolled stormwater.  During storms the stream rises very quickly and then quickly falls.  The high flow levels, even in small storms, cause stream bank erosion in the tributary. 

The planned restoration aims to control stormwater by slowing it down so it can soak into the ground and directing runoff into stormwater management facility such as a bioretention. Getting runoff to soak into the ground will reduce the volume of stormwater entering the stream.

DEP staff member recording data on the Breewood Tributary
DEP staff member gathering data on a stream

This reduction in volume and the slow release of stormwater by the stormwater management facilities will reduce peak flow levels seen during storms.  The graph below shows an example of pre-restoration conditions. After the restoration is complete, it is expected that the data will reveal a slower response in stream rise to rainfall and a longer period of more moderate flow levels during storms. This will reduce the amount of stream bank erosion and create better conditions for aquatic organisms.

 

Current Biological Data

Current biological data indicates little life exists in the stream. Samples of aquatic bugs (macroinvertebrates) are collected annually from the Breewood tributary.  The species found are pollution tolerant like the midge below.  After the watershed restoration is complete, an increase in the number of species, including species sensitive to pollution is expected to be observed.  This would indicate that conditions in the watershed have improved.

 

Stream Cross Sections

Stream cross sections are being surveyed at two locations in the Breewood Tributary to evaluate stream channel stability.  Data collected before watershed restoration will be compared to data collected after restoration to see if channel stability is improved and stream bank erosion is reduced by the restoration effort.

Weather station
Weather station at Northwood Presbyterian Church

 

Rainfall Data

Rainfall data are collected by an automated weather station at the Wheaton Regional Pond near the intersection of Dennis Avenue and Inwood Road in Wheaton.

 

 
 
 
 
 
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