The Eyes of Paint Branch - Spring 2002
Newsletter
Volume: 8 Issue: 1
Recent Data Show Severe Declines in Health of Upper Paint Branch
Data released recently from state and county regulatory agencies indicate a deterioration of water quality, loss of aquatic habitat, and increased sedimentation and erosion in the tributaries of the Upper Paint Branch watershed. Eyes of Paint Branch and local experts believe that unless immediate action is taken to address these problems, the long-term viability of this unique, high-quality, coldwater ecosystem is at risk.
The ecological system in the Upper Paint Branch is an interdependent system of tributaries, with each tributary contributing complementary characteristics that are necessary for the integrity of the overall resource. For example, the Right Fork, which is a particular concern right now, has historically had the coldest water and highest water quality of all the streams in the Paint Branch system.
The Montgomery County Department of Environmental Protection (DEP) monitors various aspects of the tributaries to document their conditions over time. Its data indicate a marked decline in the health of aquatic insects in these streams, measured by both species diversity and Index of Biotic Integrity scores, particularly in the Right Fork tributary. Monitoring results from the Timberlake-Siebel monitoring station, located just downstream on the Right Fork’s main stem, show that this section has been severely impacted by recent development taking place upstream.
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| Freshly exposed roots in this streambank on the Good Hope tributary are irrefutable evidence of significant erosion. |
The health of streams can also be gauged by monitoring the fish communities. Data from the Maryland Department of Natural Resources show that the wild brown trout population is at its lowest level in the 23-year history of monitoring. Also, the redd count--the number of trout nests observed--is down significantly.
Other troubling signs of declining stream health are also apparent. For example, embeddedness--the degree to which fine sediment particles fill the voids in the gravel substrate (and interfere with aquatic insects and smother trout eggs)--is increasing in severity and becoming more prevalent. Embeddedness is typically an indication of increased sedimentation into the stream through increased erosion of stream banks and/or local soils. The erosion of stream banks is alarming at some locations.
Changes in land cover in the watershed are equally troubling because these changes directly affect the health of the streams. For example, in spite of the 10 percent limit on impervious surfaces (such as pavement and rooftops) for new development in the county’s Upper Paint Branch Environmental Overlay Zone, there has been a drastic rise in the projected imperviousness, as high as 18 percent in the Columbia Tributary of the Right Fork when fully built-out. Not surprisingly, this tributary is showing significant signs of degradation. Data from the Maryland-National Capital Park and Planning Commission (MNCPPC) predict that there will be significant increases in imperviousness in the Right Fork, Left Fork, and Main Stem subwatersheds.
State and county regulatory agencies have made the following specific observations with regard to the outlook for the stream health in the watershed:
- The impacts of development both during and after construction cannot be adequately mitigated under current stormwater manage-ment and sediment and erosion controls.
- Since 1995 there has been a widening trend in the tributary channels. There has been measurable loss of overhead tree cover accompanying this channel widening, resulting in stream segments that are shallower and more susceptible to warming.
- The Left Fork, with its higher imperviousness, sustains more frequent and higher changes in temperature. The Right Fork is susceptible to rapid stream widening, destruction of streambed, and wider fluctuations in temperature.
- The Right Fork will probably not be able to withstand the same level of imperviousness as currently existing in the Left Fork due to its smaller base flow.
Eyes of Paint Branch expressed concerns about these observations in a letter to Councilmember Marilyn Praisner in December. In early February we met with Councilmember Praisner and the regulatory agencies to discuss these issues. Later in February we joined with several other organizations in a letter to Councilmember Marilyn Praisner requesting that a number of immediate actions be taken to arrest the degradation evident in the Upper Paint Branch watershed. The Audubon Naturalist Society, the Potomac-Patuxent chapter of Trout Unlimited, and the Anacostia Watershed Society also signed this letter. A number of other groups also wrote their own letters supporting our requested actions. Our letter is available in the Action Alert section of our Web site at www.eopb.org if you would like to know more about the specific actions requested.
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| Featherbells (Stenanthium gramineum), a plant species on the threatened list, that occurs naturally in the Thompson Seeps area of the Paint Branch watershed. |
Probably the most important request was to re-convene the Upper Paint Branch Technical Work Group to address these concerns. This 7-agency group of experts from local, state, and regional organizations defined the Special Protection Area, parkland expansion program, and Environmental Overlay Zone to protect the Paint Branch back in 1995. We hope Councilmember Praisner will call on this group once again to address these current important Paint Branch issues. We also would like stakeholder participation, including EOPB.
Public support for the Paint Branch is extremely important, particularly in this election year. County Council needs to hear from its constituents on this issue. Please take a few minutes and write a few short paragraphs on why these degraded conditions in the Paint Branch are a concern to you. Write to: Steve Silverman, President,
Montgomery County Council, 100 Maryland Avenue,Rockville, MD 20850