Furnace Branch (FB-01 and FB-02)

 

About the sites:

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-02 is located within the formerly channelized segment while FB-01 is located farther 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. 

fb01-photo

 

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Site FB-01
Time FrameBIBI (Condition)FIBI (Condition)aRBP (Condition)
2021 Results2.43 (Poor)3.00 (Fair)147 (Supporting)
Cumulative Average (2016-2022)1.86 (Very Poor)2.84 (Poor)118 (Partially Supporting)
3-year Running Average1.86 (Very Poor)2.84 (Poor)125 (Partially Supporting)

a) Fish data was only collected in 2016 and 2022.  

Site FB-02
Time FrameBIBI (Condition)FIBI (Condition)aRBP (Condition)
2022 Results2.43 (Poor)3.00 (Fair)151 (Comparable)
Cumulative Average (2016-2022)1.92 (Very Poor)2.00 (Poor)94 (Non-Supporting)
3-year Running Average2.14 (Poor)2.00 (Poor)111 (Partially Supporting)

a) Fish data was only collected in 2016 and 2022.

Site FB-01: Located downstream of the former concrete channel, this site received a BIBI score of 2.43 (Poor) in 2022, a moderate increase from the 2016-2018 pre-restoration scores which correlated to a “Very Poor” condition rating.  Post-restoration benthic communities have been dominated by non-biting midges, with lesser amounts of caddisflies, dance flies, and worms.

FB-01 Summary of Insects Collected by Sample Year:

fb01-bugs-2022

Site FB-02: This site is located within the former concrete floodway. In 2022, this site received a BIBI score of 2.43 (Poor), a moderate increase from the 2016-2018 pre-restoration scores which correlated to a “Very Poor” condition rating. In 2022, similar to sampling years prior to restoration, the benthic community was dominated by non-biting midges.  The number of damselflies has increased sharply post-restoration, while the presence of worms has declined. The cumulative average BIBI score of this site is 1.92 (Very Poor). The 3-year running average is 2.14 (Poor).

FB-02 Summary of Insects Collected by Sample Year:

FB-02 Bug Plot

Site FB-01: Fish sampling has occurred twice at this site, in 2016 (pre-restoration) and 2022 (post-restoration).  In 2016, the FIBI score was 2.67 (Poor) and only nine individual fish representing three species were observed.  In contrast,  the post-restoration sample in 2022 resulted in a FIBI score of 3.00 (Fair), with 554 individual fish representing five species collected.  Banded killifish (Fundulus diaphanus) was the dominant species in 2022. Notably, this is the only program site where both white sucker (Catostomus commersonii) and creek chubsucker (Erimyzon oblongus) have been found together.

FB-01 Summary of Fish Collected by Sample Year:

fb01-fish-2022

Site FB-02: Like FB-01, fish sampling has occurred twice at this site, in 2016 (pre-restoration) and 2022 (post-restoration). In 2016, no fish were found during sampling so the site automatically received a FIBI score of 1.00 (Very Poor).  The former concrete channel offered virtually no habitat available for fish. Additionally, the downstream end of the concrete channel was perched approximately 5 feet above the natural channel downstream, a significant barrier to fish movement in this system. Any fish that did attempt to inhabit this reach would likely be flushed out of the system during storm flow conditions, where velocities regularly reached 4 to 5 feet per second even during modest rain events.  In 2022, after the removal of the concrete channel and further restoration activities, 150 individual fish representing six species were found, with banded killifish being the dominant species. The 2022 FIBI score was 3.00 (Fair).  Similar FIBI scores and species overlap between FB-02 and FB-01 indicate that the restoration project has been successful in reconnecting these once disconnected reaches.

FB-02 Summary of Fish Collected by Sample Year:

fb02-fish-2022

Site FB-01: The RBP score for this site in 2022 was 147 (Supporting), the highest score the site has received since assessments began in 2016. The cumulative average score for this site is 118 (Partially Supporting) and the three-year average is 125 (Partially Supporting).

Site FB-02: Because this site was formerly a concrete floodway channel, the RBP habitat condition was previously rated as Non-Supporting.  However, with the implementation of the restoration and removal of the concrete channel, this site earned RBP scores of 115 (Partially Supporting) in 2021 and 151 (Comparable to Reference Conditions).  The cumulative average score for this site is in the Non-Supporting category with a score of 94 and the three-year average is 111 (Partially Supporting). 

Site FB-01: The cross-section installed for this site in 2006 could not be recovered. A new monumented section was installed in 2016 and future measurements will allow tracking of this site’s stability. An examination of the photos taken in 2006 versus 2016 provides some qualitative support that the channel had widened between 2006 and 2016. A cross-section measurement has not been performed post-restoration as the stream channel is still adjusting to the restoration.  Future work, which should begin in 2024, will seek to quantify the maintenance of stability in the restored reach.  Due to the lack of data prior to and following restoration, as well as the extensive reconfiguration of the channel during restoration, no cross-sectional overlay diagram is available at this time.

Site FB-02: Prior to restoration, the site was relatively stable as the concrete acted as a bedrock control. A cross-section measurement has not been performed since restoration work was completed, as the stream channel is still adjusting to the restoration.  Future work, which should begin in 2024, will seek to quantify the maintenance of stability in the restored reach.  Due to the extensive reconfiguration of the channel during restoration and the lack of post-restoration survey data, no cross-sectional overlay diagram is available at this time.

FB-01
YearBIBI (Condition)FIBI (Condition)RPB (Condition)
20161.86 (VP)---114 (PS)
20171.86 (VP)---104 (PS)
20181.00 (VP)---90 (NS)
2019---------
2020---------
20212.14 (P)---137 (S)
20222.43 (P)3.00 (F)147 (S)
FB-02
YearBIBI (Condition)FIBI (Condition)RPB (Condition)
20161.86 (VP)---71 (NS)
20171.29 (VP)---64 (NS)
20181.57 (VP)---67 (NS)
2019---------
2020---------
20212.43 (P)---115 (PS)
20222.43 (P)3.00 (F)151 (C)
Station Summary
 Average BIBI (SD)a3-Year Average BIBI (SD)aAverage RPB (SD)a3-Year Average RBP (SD)a
FB-011.86 (0.53)1.86 (0.76)118 (23)125 (30)
FB-021.92 (0.51)2.14 (0.50)94 (38)111 (42)

a) No data is available for 2019 or 2020.

b) Fish data collected in 2016 and 2022 only.

SD = Standard Deviation