Cat Branch (CA-01)


About the site:

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 percent of the drainage area.


Time Frame

BIBI (Condition)

FIBI (Condition)

RBP (Condition)

2022 Results

2.43 (Poor)

3.00 (Fair)

151 (Comparable)

Cumulative Average (2016-2022)

2.07 (Poor)

3.00 (Fair)

122 (Partially Supporting)

3-year Running Average

1.95 (Very Poor)

3.00 (Fair)

126 (Supporting)

This site was sampled once in 2016 prior to restoration efforts.  After work was completed, sampling resumed in 2020.  In 2022, the site received a BIBI score of 2.43 (Poor), which is an improvement from the first two post-restoration years, and also matches its pre-restoration value.   However, while the pre-restoration sample was dominated by amphipods and clams, post-restoration samples are dominated by non-biting midges.  Additionally, 2022 marks the first year that caddisflies were collected at the site.

CA-01 Summary of Insects Collected by Sample Year:

CA01 Bugs

Fish sampling was conducted at the site for the first time in 2022.  The site received a FIBI score of 3.00 (Fair) in 2022.  A total of 466 individual fish representing seven different species were observed in 2022.  Eastern mosquitofish (Gambusia holbrooki) was the dominant species, making up approximately 70 percent of the sample.

CA-01 Summary of Fish Collected by Sample Year:

CA01 Fish

In 2016, prior to restoration, the site received an RBP score of 112 (Partially Supporting).  Habitat quality was predictably low directly following restoration work, however, the site has improved each year since 2020 and in 2022 received an RBP score of 151 (Comparable to Reference Conditions).   

Geomorphology at the site was first measured in 2007 and again in 2016, prior to the commencement of restoration activities. Prior to restoration, the channel was narrow and deeply incised.  The restoration work widened the channel considerably and reconnected the stream with its floodplain. Stable channel conditions appear to have been created, as little change has been observed in the profile since 2020.

CA-01 Cross-Section Comparison:

YearBIBI (Condition)FIBI (Condition)1RBP (Condition)
20162.43 (P)--112 (PS)
20201.86 (VP)--93 (NS)
20211.57 (VP)--134 (NS)
20222.43 (P)3.00 (F)151 (C)
Station Summary
 Average BIBI (SD)3-Year BIBI Average (SD)Average RBP (SD)3-Year RBP Average (SD)Average FIBI (SD)13-Year FIBI Average (SD)1
CA-012.07 (0.43)1.95 (0.44)122 (25)126 (30)3.00 (NA)3.00 (NA)

1) No data.

SD = Standard Deviation