NORTH COUNTRY PRESERVATION

OCCASIONAL RESEARCH REPORT

AUGUST 5, 2007

 

In anticipation of the Comprehensive Zoning Map Process, North County Preservation is issuing reports summarizing research about the environmental and quality of life issues which zoning decisions impact.  These reports in conjunction with the North County Preservation CZMP Geographical Information System will allow Baltimore County to assess proposed zoning changes in terms of their environmental and quality of life impact.  Our first report concerns the current status of Brook Trout in Baltimore County.

 

 

CZMP AND NATIVE BROOK TROUT IN BALTIMORE COUNTY

 

Native brook trout are disappearing from streams in Baltimore County.  This is a problem not only for sports fishermen, but this indicator species shows that the County’s streams are suffering from the effects of development.  Like canaries in a mine, suffering brook trout indicate that water quality has deteriorated and that the other species depending on the same habitat are also suffering.

 

Baltimore County’s Comprehensive Zoning Map Process (CZMP), which occurs every four years, is underway.  Decisions will be made in the upcoming months about the zoning and land use of every property in the County.  North County Preservation (NCP), Inc., a coalition of community associations in northern Baltimore County, urges the protection of corridors and surrounding wetlands of streams inhabited by brook trout to assure preservation of this species. 

 

A stream is where a community’s environmental and land use legacies come to roost.  The species that live and thrive in a stream say a great deal about the surrounding community.  Native-reproducing brook trout are an integral part of Baltimore County’s natural heritage because they are Maryland’s only native freshwater trout species.  Their sensitivity to environmental stress and their dwindled populations demonstrate that we are at a critical time for preserving the County’s natural habitats.   Brook trout are a biological indicator species because they represent a whole suite of unique aquatic and terrestrial organisms that live in the same habitat.

 

The Maryland Department of Natural Resources (DNR) lists brook trout as a “Species of Greatest Need of Conservation” in its federally mandated Wildlife Diversity Conservation Plan.  Also, the DNR’s Inland Fisheries Management Division, which is responsible for management of freshwater sport fish species statewide, developed a brook trout Fisheries Management Plan (FMP). Brook trout streams are identified on State and County land use maps because they are considered worthy of preservation, and their presence affects the County’s zoning decisions.

 

Brook trout require relatively pristine conditions and have difficulty surviving when water temperatures exceed 680 F.   They live in headwater streams that are silt free and spring-fed with riffle-runs.  The streambed should contain a mix of gravels, cobble, and sand.  The stream flow and water temperatures should be relatively stable. The stream banks should be well vegetated and secure, to provide cover and shade and to limit silt from erosion.

 

Zoning decisions must limit development near streams with brook trout to limit chemical discharges and non-point sources of contamination, some of which result from excessive impervious surface area (such as parking lots and roads). Residential development adds to the amount of impervious surface and will have a negative impact on the viability of brook trout if not curtailed in northern Baltimore County.  Brook trout streams begin to fail when impervious surfaces exceed 2% of a watershed’s area.  Impervious surfaces comprise about 8 percent of five-acre residential lots, 16 percent of one-acre residential lots, and 26 percent of quarter-acre residential lots.

 

The Gunpowder River Basin supports the next highest number of brook trout stream populations in Maryland (after Garrett County in undeveloped Western Maryland), with 50 miles of 31 streams supporting 25.2% of the State’s brook trout. The cold underground water that feeds the streams in northern Baltimore County provides an ideal environment. However, the vast majority of brook trout populations are trapped in headwater portions of streams, with no self-sustaining population in the mainstream of the Gunpowder River.  The brook trout’s isolation in headwater streams results from physical blockages (e.g., fallen trees in the stream), high water temperatures and chemical pollution (pH) downstream, and competition from the non-native brown trout.  Such localized destruction of the brook trout’s habitat prevents the brook trout populations from intermingling, which stresses the populations’ genetic diversity.

 

NCP has developed a Geographic Information System with layers of information about every County property, including the location of trout streams.  This database has mapping and analysis capabilities that will help citizens and County planners identify properties worthy of preservation from development.  One of the most important layers in this GIS shows the distribution of brook trout habitats in Baltimore County.  For information, you may check out the group’s website at www.northcountypreservation.org or contact NCP’s President Irving Spitzberg at ijs@northcountypreservation.org .  See the attached additional research information and maps of brook trout in Baltimore County.  For further information about the brook trout in Baltimore County, contact Janet Schollenberger at jscholle4@yahoo.com  and Jeff Gernand at jgernand3@yahoo.com .

 

Native Brook Trout in Baltimore County

 

Background:  When you stand in a stream, you are more connected to your environment than virtually anywhere else.  A stream is where a community’s environmental and land use legacies come to roost.  The species that live and thrive in a stream say a great deal about the surrounding community.  Native-reproducing brook trout populations are an integral part of Baltimore County’s natural heritage.  Their sensitivity to environmental stress and dwindled population levels demonstrate that we are at a critical junction in time for preserving the natural habitats of Baltimore County.   This report draws from research performed by the Maryland Department of Natural Resources (DNR), which has listed brook trout as a “Species of Greatest Need of Conservation” in its federally mandated Wildlife Diversity Conservation Plan Plan 1, 2.

 

Action:  The North County Institute urges Baltimore County to protect the corridors and surrounding wetlands of streams inhabited by brook trout for the preservation of this species. Baltimore County should assess all rezoning decisions during the Comprehensive Zoning Map Process by their impact on brook trout habitat.  No development should be allowed on properties directly in or adjacent to corridors including brook trout habitat. 

 

Technical Basis:  Land development in the contributing watersheds must be regulated to limit chemical discharges and non-point sources of contamination, which may result from excessive impervious surface area. Residential development clearly adds to the amount of impervious surface and will have a negative impact on the viability of brook trout if not curtailed in northern Baltimore County.   Technical research has found that brook trout streams begin to fail when impervious surfaces exceed 2% of a watershed1. According to a mapping analysis by McClintock3, five-acre residential lots had an average of 8 percent impervious surfaces; one-acre residential lots had an impervious coefficient of 16 percent; and quarter-acre residential lots had a coefficient of 26 percent.

 

Brook trout are Maryland’s only native freshwater trout species1.  They are considered a biological indicator species because they represent a whole suite of unique aquatic and terrestrial organisms that occupy and share the same habitat. Loss of brook trout from a system indicates negative changes to the habitat and the condition of our ecology.  Brook trout require relatively pristine conditions for survival and typically cannot survive when water temperatures exceed 680 F.   Their habitat in Maryland is typically headwater streams, but includes a small number of moderately sized tailwaters with average widths up to approximately 40 meters. Silt free, spring-fed, riffle-run areas that contain mixed gravels, cobble, and sand, generally characterize the habitat.  The stream flow and water temperatures should be relatively stable. The stream banks should be well vegetated and secure, to provide cover and shade and to limit silt from erosion.

 

While no economic valuation of the recreational fishery has been done in Maryland, findings from Pennsylvania, which has a similar wild brook trout fishery, show the fishery’s significant economic impact. Wild trout anglers in Pennsylvania contribute more than $2 million annually to local economies.

 

Human alterations to the environment over the last several centuries (including clear cutting of forests, establishing large agricultural areas, and urbanization) have resulted in brook trout disappearing from 62% of their historic habitat in Maryland. The brook trout’s dependence on cold, clear water for survival makes it extremely vulnerable to urbanization. A reduction in the forested buffers of streams due to development increases the water temperatures and turbidity. Clear cutting has been shown to increase the water temperature as much as 70 C.   Therefore, brook trout populations cannot survive in watersheds where human land use exceeds 18%. If the impervious surface area exceeds 0.5% in a watershed, brook trout will typically be extirpated. There are also long-term threats to brook trout populations such as global warming. Current predictions indicate that warming water temperatures over the next 100 years could eliminate brook trout populations statewide by the year 2100, except in Garrett County of Western Maryland.  Of the 151 streams where brook trout populations are still found in Maryland, over half are in westernmost Garrett County, the least developed area of the State.

 

The Gunpowder River Basin supports the next highest number of brook trout stream populations in Maryland, with 31 streams supporting 25.2% of the State’s brook trout. The cold underground water that feeds the streams in northern Baltimore County provides an ideal environment. However, the vast majority of brook trout populations are confined to headwater portions of streams, with no self-sustaining population in the mainstream of the Gunpowder River.  The brook trout’s isolation in headwater streams results from physical blockages (e.g., fallen trees in the stream), high water temperatures and chemical pollution (pH) downstream, and competition from the non-native brown trout.  Such localized destruction of the brook trout’s habitat prevents the brook trout populations from intermingling, which stresses the populations’ genetic diversity.  (To view a map of the isolated streams inhabited by the brook trout, see page 78 of the MD DNR 2006 Maryland Brook Trout Fisheries Management Plan1.  For a map showing the brook trout watersheds of Baltimore County, click the following link: http://www.ceds.org/BaltimoreCounty/Trout-Watersheds.pdf.)

 

Geographic coordinates of Baltimore County’s self-sustaining brook trout populations show that brook trout inhabit 50 miles of streams in the Gunpowder Basin. A major difficulty in managing the brook trout resource is that only 11% of Maryland’s brook trout streams and stream miles are fully within State-owned lands.  The vast majority of the brook trout’s habitat is on private land or a mix of private and public lands. (To view the tables of land ownership along the streams, see Table 2, page 63 of the MD DNR 2006 Maryland Brook Trout Fisheries Management Plan1.)

 

Concern for the status of the brook trout resource prompted the Maryland Department of Natural Resources (MD DNR) Inland Fisheries Management Division, which is responsible for management of statewide freshwater sport fish species, to develop a brook trout Fisheries Management Plan (FMP). Partners in this effort include researchers from the University of Maryland Center for Environmental Studies Appalachian Laboratory (UMCES-AL), MD DNR Fisheries Service, and the MD DNR Biological Stream Survey (MBSS). There is increasing local and national recognition of the uniqueness and quality of fishing for native brook trout. This recognition is highlighted by the creation of the multi-state Eastern Brook Trout Joint Venture (EBTJV) and the formation of the Maryland Brook Trout Alliance, a citizen-based Maryland brook trout advocacy group.

 

References:

1. Quoted Excerpts taken from 2006 Maryland Brook Trout Fisheries Management Plan, Maryland Department of Natural Resources Fisheries Service Inland Fisheries Management Division,  http://www.dnr.state.md.us/fisheries/pdfs/MDBrookTrout006.pdf

2.  Survey and Management of Maryland’s Fishery Resources, Maryland Department of Natural Resources Fisheries Service and U.S. Fish and Wildlife Services, June 2000 http://www.vims.edu/GreyLit/MDNR/f-48-r-10.

3. Tom McClintock, University of Wisconsin-Madison, and Larry Cutforth, Dane County Regional Planning Commission Land Use Impacts for the Black Earth Creek Watershed Modeled With GIS, Dane County, Wisconsin, ArcNews 25(2): 26–27.

 

NOTE:  MAPS OF BROOK AND BROWN TROUT HABITATS ARE AVAILABLE FROM THE NCP CZMP GIS.  WE ATTACH A NCP CZMP GIS BITMAP FILE SHOWING THE EXTENSIVE BROOK AND BROWN TROUT HABITATS IN BALTIMORE COUNTY. DARK GREEN AREAS HAVE BROOK TROUT, BROWN AREAS HAVE BROWN TROUT, AND BRIGHT GREEN AREAS HAVE BOTH.