Mill Creek (MC-01, MC-02, MC-03, and MC-04)


About the sites:

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.







Site MC-01
Time FrameBIBI (Condition)FIBI (Condition)RBP (Condition)
2022 Results2.14 (Poor)3.33 (Fair)156 (Comparable)
Cumulative Average (2010-2022)2.58 (Poor)2.87 (Poor)122 (Partially Supporting)
3-year Running Average2.62 (Poor)2.89 (Poor)130 (Support
Site MC-02
Time FrameBIBI (Condition)FIBI (Condition)RBP (Condition)
2022 Results2.71 (Poor)1.67 (Very Poor)99 (Non-Supporting)
Cumulative Average (2010-2022)2.45 (Poor)1.67 (Very Poor)108 (Partially Supporting)
3-year Running Average2.52 (Poor)1.67 (Very Poor)99 (Non-Supporting)
Site MC-03
Time FrameBIBI (Condition)FIBI (Condition)RBP (Condition)
2022 Results2.71 (Poor)2.00 (Poor)103 (Partially Supporting)
Cumulative Average (2010-2022)2.41 (Poor)1.93 (Very Poor)117 (Partially Supporting)
3-year Running Average2.14 (Poor)1.78 (Very Poor)11 (Partially Supporting)
Site MC-04
Time FrameBIBI (Condition)FIBI (Condition)RBP (Condition)
2022 Results2.14 (Poor)1.67 (Very Poor)104 (Partially Supporting)
Cumulative Average (2010-2022)2.40 (Poor)1.80 (Very Poor)111 (Partially Supporting)
3-year Running Average2.14 (Poor)1.67 (Very Poor)116 (Partially Supporting)

1) No fish data for 2021. Cumulative and 3-year running averages are through 2020.

Site MC-01: MC-01 had a BIBI score of 2.14 (Poor) in 2022.  The site has seen periods of oscillation between “Fair” and “Poor” ratings since 2011.  The three-year running average BIBI score is 2.62 (Poor) and the cumulative average is 2.58 (Poor). In 2022, like previous years, non-biting midges, and to a lesser extent worms, dominated the sample. Caddisfly representation has periodically fluctuated, with only one specimen being observed in 2022.

MC-01 Summary of Insects Collected by Sample Year:


Site MC-02: This site is located upstream of MC-01 and downstream of the confluence of the two reaches that contain MC-03 and MC-04. This site has an intact riparian buffer of approximately 60 meters on both sides of the stream.  In 2022, this site received a BIBI score of 2.71(Poor).  Like MC-01, the 2022 sample was dominated by non-biting midges and worms, while numbers of other organisms - such as caddisflies and some beetle species - have fluctuated over the years. The cumulative average and three-year running average BIBI condition scores are 2.45 (Poor) and 2.52 (Poor), respectively.

MC-02 Summary of Insects Collected by Sample Year:


Site MC-03: MC-03 is located on the western branch of Mill Creek after the split upstream of MC-02.  It is similar in character to the other Mill Creek sites in that it is well-buffered by a forested riparian area, particularly on the east side of the stream. The 2022 BIBI score was 2.71 (Poor).  Non-biting midges and worms were the dominant organisms in the 2022 sample, consistent with previous years. The cumulative and three-year running averages for this site are 2.41 (Poor) and 2.14 (Poor), respectively.

MC-03 Summary of Insects Collected by Sample Year:


Site MC-04: MC-04 is located on the eastern branch of Mill Creek after the split upstream of MC-02.  Like the other Mill Creek sites, MC-04 is well-buffered by a forested riparian area, particularly on the west side of the stream.  The 2022 BIBI score for MC-04 was 2.14 (Poor). The 2022 sample was dominated by non-biting midges and by worms; other taxa accounted for only 7 percent of the sample. The site has received a rating of “Poor” or “Very Poor” for all years of monitoring except for 2018 when it received a rating of “Fair”. The 2022 sample was the second consecutive sample in which caddisflies were absent after being present in all samples from 2010 to 2020. The cumulative and three-year running average BIBIs for this site are 2.40 (Poor) and 2.14 (Poor), respectively.

MC-04 Summary of Insects Collected by Sample Year:


Site MC-01: The site received a FIBI score 3.33 (Fair) in 2022. Nine species were observed in 2022, with the American eel (Anguilla rostrata) and brown bullhead (Ameiurus nebulosus) being the most abundant species.  Fifteen different species have been observed here since 2015, making it the most diverse site in the long-term targeted monitoring program, despite levels of impervious surface (~26%) that often result in depressed fish populations. Also of note, the number of individual fish per sample has more than doubled between 2022 and 2016.

MC-01 Summary of Fish Collected by Sample Year:


Site MC-02: In 2022, like all previous sampling years, the FIBI score was 1.67 (Very Poor). Twenty individual fish, from only two species, American eel and eastern mudminnow (Umbra pygmaea), were collected during the 2022 sampling.

MC-02 Summary of Fish Collected by Sample Year:


Site MC-03: The site received a FIBI score of 2.00 (Poor) in 2022.  The FIBI at MC-03 has been in the “Poor”or  “Very Poor” categories every sampling year.  American eel has been the only species observed at this site since 2018. Six specimens were collected in 2022, a 100% increase over the 2020 sample.

MC-03 Summary of Fish Collected by Sample Year:


Site MC-04: The site received a FIBI score of 1.67 (Very Poor) in 2022, the same score observed in 2018 and 2020. Seven specimens from two species were identified in 2022: American eel and eastern mudminnow.

MC-04 Summary of Fish Collected by Sample Year:


Site MC-01: In 2022, initial post-restoration habitat conditions resulted in an RBP score of 156 (Comparable to Reference Conditions).  The site had been rated as “Partially Supporting” or “Supporting” in all previous years prior to restoration.

Site MC-02: The 2022 RBP score for MC-02 was 99 (Non-Supporting).  The site has consistently been within the high end of scores in the “Non-Supporting” category and the low end of scores in the “Partially Supporting” category since 2011.  In 2022 this site had moderate to low scores for bank stability and bank vegetative protection, high scores in riparian vegetation, and moderate to high scores in sediment deposition and variability in channel flow.

Site MC-03: After the site received its highest habitat rating in 2021 with an RBP score of 137 (Supporting), the 2022 score fell to 103 (Partially Supporting).  The site's habitat ratings have varied between “Non-Supporting,” "Partially Supporting,” and “Supporting” since 2010.  The cumulative average RBP score is 117 (Partially Supporting) and the three-year running average is 113 (Partially Supporting).

Site MC-04: An RBP score of 104 (Partially Supporting) was obtained at the site in 2022. The habitat has been rated as “Partially Supporting” in 11 of the 13 years of monitoring at the site.  

Site MC-01: An examination of the cross-section measurements indicates that this stream reach experienced instability prior to restoration (years 2010-2021). Severe incision of the stream bed occurred over that time frame, as the elevation of the channel bottom dropped by nearly three feet between 2010 and 2021. The stream restoration completed in 2022 required the reconstruction of the upper 100 meters of this stream on the opposite side of the river valley.   Future measurements will determine the post-restoration stability of this site.

MC-01 Cross-Section Comparison:


Site MC-02: Little change has occurred in the channel form at MC-02 since measurements began in 2010 aside from an undercut that began forming on the left bank in 2016. Additionally, the channel bottom appears to be aggrading at a slow rate (a little over one foot in the 13 years of observation).

MC-02 Cross-Section Comparison:


Site MC-03: The channel form at this site has remained relatively stable since 2010, although a slight retreat of the left bank and downcutting on the left margin of the stream bed has been observed over the past three years.

MC-03 Cross-Section Comparison:


Site MC-04: The cross-section at this site has shown little change over the 13 years of geomorphic data collection. Incision and deposition have oscillated over the years here, with typical changes from year to year around 0.2 feet or less. A slight undercut began to form on the right bank in 2021 and, in 2022, a portion of the right bank appears to have slumped off. Future assessments at this site will determine if the site is becoming unstable.

MC-04 Cross-Section Comparison:

YearBIBI (Condition)FIBI (Condition)RPB (Condition)
20101.86 (VP)---123 (PS)
20113.00 (F)---120 (PS)
20122.43 (P)---128 (S)
20132.14 (P)---125 (PS)
20143.00 (F)---111 (PS)
20153.00 (P)3.00 (F)117 (PS)
20162.71 (P)2.67 (P)125 (PS)
20172.43 (P)---114 (PS)
20182.71 (P)2.33 (P)125 (PS)
20192.43 (P)--110 (PS)
20203.00 (F)3.00 (F)110 (PS)
20212.71 (P)--125 (PS)
20222.14 (P)3.33 (F)1
YearBIBI (Condition)FIBI (Condition)RBP (Condition)
20103.00 (F)---130 (S)
20112.71 (P)---107 (PS)
20123.29 (F)---102 (PS)
20132.71 (P)---104 (PS)
20143.00 (F)---103 (PS)
20151.86 (VP)1.67 (VP)93 (NS)
20161.57 (VP)1.67 (VP)123 (PS)
20173.00 (F)---109 (PS)
20181.00 (VP)1.67 (VP)123 (PS)
20192.14 (P)--121 (PS)
20202.14 (P)1.67 (VP)88 (NS)
20212.71 (P)--110 (PS)
20222.71 (P)1.67 (VP)99 (NS)
YearBIBI (Condition)FIBI (Condition)RPB (Condition)
20102.71 (P)---111 (PS)
20112.43 (P)---115 (PS)
20122.14 (P)---133 (S)
20133.00 (F)---113 (PS)
20143.00 (F)---117 (PS)
20153.00 (F)2.00 (P)98 (NS)
20162.71 (P)2.33 (P)133 (S)
20172.71 (P)---102 (PS)
20181.00 (VP)1.67 (VP)136 (S)
20192.14 (P)--118 (PS)
20202.71 (P)1.67 (VP)99 (NS)
20211.00 (VP)--137 (S)
20222.71 (P)2.00 (P)103 (PS)
YearBIBI (Condition)FIBI (Condition)RBP (Condition)
20102.43 (P)---113 (PS)
20112.71 (P)---110 (PS)
20122.14 (P)---122 (PS)
20132.14 (P)---100 (NS)
20142.71 (P)---108 (PS)
20151.57 (VP)2.00 (P)89 (NS)
20162.71 (P)2.00 (P)114 (PS)
20172.71 (P)---111 (PS)
20183.00 (F)1.67 (VP)121 (PS)
20192.71 (P)--110 (PS)
20202.14 (P)1.67 (VP)99 (NS)
20212.14 (P)--121 (PS)
20222.14 (P)1.67 (VP)104 (PS)
Station Summary
 Average BIBI (SD)3-Year Average BIBI (SD)Average RPB (SD)3-Year Average RBP (SD)
MC-012.58 (0.38)2.62 (0.44)122 (12)130 (23)
MC-022.45 (0.66)2.52 (0.33)108 (12)99(11)
MC-032.41 (0.68)2.14 (0.99)117 (14)113 (21)
MC-042.40 (0.39)2.14 (0)111 (10)116 (11)

SD = Standard Deviation