The Anne Arundel County Bureau of Watershed Protection and Restoration’s Ecological Assessment & Evaluation Program routinely collects biological, habitat, and geomorphological data from local streams as part of a long-term targeted biological monitoring program. The monitoring sites are located on stream reaches where stream restoration activities have occurred or are planned for the future.
For stream reaches where restoration work has not occurred, the purpose of this effort is to continue, or begin, an evaluation of baseline biological conditions before restoration work commences in efforts to identify potential geomorphic (stream channel) instability within the reaches of interest, and to evaluate habitat conditions within the study reaches.
For sites that have already been restored, the purpose of the work is to evaluate any changes in habitat or biological conditions observed in the restored reaches, and/or in reaches immediately upstream or downstream of restored reaches. The eighteen sampling sites from ten different streams are represented on the map below.
The sites were assessed using methodologies based on the Maryland Biological Stream Survey (MBSS) and BWPR Sampling Protocols (AACo 2023).
Two primary measures of biological health were used in this work. The Benthic Index of Biotic Integrity (BIBI) is a multimetric index calculated from a sample of the benthic macroinvertebrates (insects that live in the stream) using procedures developed by the MBSS. Benthic macroinvertebrates are sampled annually. The Fish Index of Biotic Integrity (FIBI) is also a multimetric index based upon a sample of the fish population also using methodologies developed by the MBSS. Fish are sampled every other year to protect the fish population from frequent collection and handling. The kinds and numbers of benthic macroinvertebrates or fish present in a stream, along with other metrics are used to calculate a score between 1-5, with a 1 being a Poor score and a 5 designated as a Good score.
BIBI/FIBI Score Range
1– 1.99 – Very Poor
2– 2.99 – Poor
3– 3.99 – Fair
4– 5.00 – Good
Fish and macroinvertebrates are a great indicators of stream health because some species are sensitive to disturbances. This sensitivity allows our biologists to assess where issues may exist based on the communities present. For example, some fish are very tolerant of low dissolved oxygen levels while others are extremely sensitive to low dissolved oxygen levels. Looking at biological samples, habitat assessments, and water chemistry samples can provide a good picture of the stream health. Examples of potential problems may include low dissolved oxygen, high sediment concentrations, agricultural or industrial runoff, or lack of habitat. The information gathered can guide watershed partners in restoration or protection efforts.
List of Common Maryland Stream Fishes
List of Common Maryland Stream Macroinvertebrates
Aquatic habitat quality was measured using the U.S. EPA’s Rapid Bioassessment Protocol (RBP) method for low-gradient streams, which is a multimetric visual assessment that scores various habitat features believed critical in supporting high-quality biological communities. Most metrics used are scored on a scale of 0 to 20. Those that are scored for each side of the stream are scored from 0 to 10. The individual metric scores are summed and a total score is used to place the reach in a qualitative habitat category.
RBP Score Range
151 + - Comparable (to reference)
126 - 150 - Supporting (aquatic life uses)
101 - 125 - Partially Supporting
≤100 - Non-Supporting
Sewell Spring Branch (Reference Site) - Consisting of a single site located on Sewell Spring Branch, a direct tributary to the Severn River, station SR-01 has a drainage area of approximately 450 acres. With the exception of 2006, this site has been continuously monitored since 2005. The Sewell Spring Branch watershed is mostly forested (approximately 55%) with only 10% impervious surface, most of which is disconnected. This site was established during geomorphic work performed for another project (Starr et al. 2010) and has become a de-facto reference site for the County’s biological monitoring work.
Cat Branch - A single monitoring site, CA-01, was established on Cat Branch in 2016. The site is located on the east side of College Parkway directly across from Broadneck Park. The site was first sampled for stream macroinvertebrates in 2016 prior to the start of construction on a stream restoration project. Construction was completed in 2019 and sampling resumed the following year in 2020. Impervious surface accounts for approximately 28% of the drainage area.
Cypress Creek - Two long-term monitoring stations, CY-01 and CY-02, were located on Cypress Creek, both downstream of the crossing at Maryland Route 2. This is a highly developed watershed and both stations were subjected to runoff from extensive impervious surfaces, with coverage estimated to be approximately 48% for CY-01 and 50% for CY-02. Both sites were located within a reach where an extensive stream restoration project was completed in 2013. Sampling at both sites began in 2009, and thus pre- and post-restoration data were collected. Benthic macroinvertebrate sampling and habitat assessment at CY-01 ceased after 2019, and fish sampling ceased after 2020 due to the arrival of beavers in the project area. At site CY-02, fish sampling ceased after 2020, and benthic macroinvertebrate and habitat sampling ceased after 2021 due to beaver activity. Both sites are now retired from the program.
Dividing Creek - There are two stations located in the study area on Dividing Creek. DC-01 is located just upstream of the College Parkway crossing while DC-02 is further upstream on Anne Arundel Community College property behind the Florestano Building. Both sites have been monitored continuously since 2010. In early 2016, a restoration effort utilizing a wetland seepage approach was completed in between the two sites. Although DC-02 was within the extent of the restoration project footprint, the site itself was not physically altered by construction activities. Approximately 27% of each site's drainage area consists of impervious surfaces.
Ferndale Branch - FD-01, located on Ferndale Branch north of Penrod Court in Glen Burnie, is approximately 800 ft upstream of the confluence with Sawmill Creek. The site was sampled between 2017 and 2021 as part of a separate study of the Sawmill Creek watershed. The site was added to the targeted monitoring program in 2021 in advance of a planned stream restoration scheduled to begin in 2022. The site is located in a highly developed area, with 34 percent of the site’s drainage area consisting of impervious surface. Construction of an extensive stream restoration project upstream of FD-01 was completed in 2023.
Furnace Branch - Sampling began in 2016 at two stations in the study area on Furnace Branch. The reach of interest consisted of a concrete channel beginning at a large culvert under New Jersey Avenue, which drained to a natural channel just upstream of Maryland Route 10. Removal of the concrete channel and restoration of the stream system began in late 2018 and concluded in 2020. Site FB-01 is located within the formerly channelized segment while FB-02 is located further downstream. No sampling occurred at either site in 2019 or 2020 due to the restoration work. Sampling resumed in 2021 after restoration work was completed. FB-01’s drainage area is approximately 48% impervious, while approximately 54% of FB-02’s drainage area is impervious.
Howard's Branch - There are two stations - HB-01 and HB-02 - located in the study area on Howard's Branch. The two sites bracket a segment of the stream that was restored in 2000 using a wetland seepage system approach. All sampling at Howard’s Branch occurred post-restoration, beginning in 2007 and ending in 2019 when the stream was retired from the Targeted Monitoring Program. Impervious surface levels are low within the drainage areas of both sites - about 9% in HB-01’s drainage area and about 10% in HB-02’s. This stream restoration project resulted in the formation of large, deep pools throughout the restored area, making it difficult to sample using standard County bioassessment techniques. While both sites were retired from the targeted monitoring program in 2019, HB-02 was sampled again in 2022 as part of a separate study.
Irving Branch - Site IB-01 is located on Irving Branch just upstream of the road crossing at Dorsey Road. IB-01 was sampled between 2017 and 2021 as part of a separate study of the Sawmill Creek watershed. With a project to restore nearly the entire stream anticipated to break ground in 2023, the site was added to the targeted monitoring program in 2022. Impervious surface accounts for nearly 25% of land use within the site’s drainage area.
Mill Creek - There are four stations located in the study area on Mill Creek, all of which have been sampled continuously since 2010. Site MC-01 is located at the lower end of the watershed, just downstream of the road crossing at Jones Station Rd. Sites MC-02, MC-03, and MC-04 are found in the headwaters to the south and west of College Parkway. Impervious surface levels range from 20% at MC-04 to 27% at MC-01, but the stream is well buffered by an extensive forested riparian area, particularly at the upstream sites. MC-01 was restored in 2021 and restoration of the upstream reaches (MC-02, -03, and -04) is planned in the near future.
Muddy Bridge Branch - Two monitoring sites are located on Muddy Bridge Branch in Glen Burnie. MB-01 is located downstream of the 8th Ave road crossing and approximately 300 feet upstream of the confluence with Sawmill Creek. MB-02 is located approximately one mile upstream of MB-01, directly east of Aviation Boulevard and BWI Airport. Both sites were monitored continuously between 2017 and 2021 as part of a separate study of the Sawmill Creek watershed.Both sites are in highly developed areas, and both sites have drainage areas with high percentages of impervious surface - 49% in MB-01 and 51% in MB-02. MB-02 lies within the extent of a former stream restoration project completed in the early 1990s by the State of Maryland that has since failed. With a second restoration project planned at MB-02 in the near future, both sites were added to the targeted monitoring program in 2022.
Click on a location to learn more about the biological and habitat data for a specific reach: