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Howard's Branch (HB-01 and HB-02)

About the site:

There are two stations located in the study area on Howard's Branch, bracketing a reach restored in 2000 using a wetland seepage system approach. Sampled since 2007, the data collected are all post-restoration. Impervious surface levels are low, with about 9% found in the drainage area of site HB-01 and about 10% found upstream of HB-02. Typical of the wetland seepage system approach, very large and deep pools are present throughout the restored system making it very difficult to sample using standard County bioassessment techniques because the reach is very deep in some areas.

CY-01

CY-01

2019 Summary Report:

Site HB-01
Time FrameBIBI (Condition)FIBI (Condition)RBP (Condition)
2019 Results2.71 (Poor)--1124 (Partially Supporting)
Cumulative Average (2007-2019)2.57 (Poor)2.55 (Poor)124 (Partially Supporting)
3-year Running Average2.57 (Poor)2.67(Poor)132 (Supporting)
Site HB-02
Time FrameBIBI (Condition)FIBI (Condition)RBP (Condition)
2019 Results1.86 (Very Poor)--1124 (Partially Supporting)
Cumulative Average (2007-2019)2.58 (Poor)2.78 (Poor)127 (Supporting)
3-year Running Average2.07 (Poor)2.33 (Poor)133 (Supporting)
1) No fish data for 2019. Cumulative and 3-Year Running Averages are through 2018.

Benthic IBI: 

Site HB-01: Located just downstream of the restoration project, the 2019 BIBI was 2.71, in the Poor range. This is higher than the 2018 score of 2.43 in the Poor range. This score is also higher than the cumulative average (2.57) and the three year running average of 2.57. The 2019 composition of insects includes non-biting midges making up majority of the sample and caddisflies making up about 11%. These amounts are synonymous with 2018 results, except that 2018 had less worms and caddisflies and more riffle beetles.

HB-01 Sample of Insects Collected by Sample Year

CY01 Bugs
Click to enlarge

Site HB-02: Located approximately 500 feet upstream of the restoration project area, the 2019 BIBI was in the Very Poor category at 1.86. Benthic macroinvertebrate community conditions appear to be declining here, as the current BIBI score is lower than the cumulative average (2.58) and the three-year running average (2.07). The insect summary for this site shows non-biting midges in the majority at 31% in 2019. The number of craneflies in 2019 increased from 2018 as well as the number of worms. Additionally, flatworms were found this year, but not soldierflies, unlike 2018’s sample. 

HB-02 Sample of Insects Collected by Sample Year

CY01 Bugs
Click to enlarge

Fish IBI: No fish were sampled in 2019. The 2018 results are described below.

Site HB-01The fish community shows some improvement since 2016, with the FIBI measured at 3.00, or Fair. A total of 110 fish, representing five species, were collected in 2018. Fish found in 2018 include the golden shiner, American eel, pumpkinseed, brown bull head, and the eastern mosquitofish. These same species of fish were found in 2016.

Site HB-02The 2018 FIBI received a score of 2.33, which is in the Poor range. This is the same score from 2016. Species observed in 2018 include golden shiner, American eel, pumpkinseed, brown bullhead, and eastern mosquitofish. The same assemblage of species was observed in 2016.

Physical Habitat and Geomorphic Assessments

Site HB-01RPB conditions also appear to be declining. The 2019 score of 124 (Partially Supporting) was lower than the 2018 score of 134 (Supporting). Scores in epifaunal substrate, sediment deposition, and bank stability contributed to the overall evaluation. The cumulative average and the three-year running average were 127 and 132, respectively. Channel cross section conditions are relatively stable. The 2018 measurement shows about a 0.25 foot increase in stream bottom elevation over the 2018 measurement, indicative of a pulse of sediment delivered to the system. Continued measurements will provide insight into stability conditions at this site. This reach is classified as a Rosgen E5 stream type.

HB-01 Cross Section Comparison 

Cross Section
XS
Click to enlarge

Site HB-02Habitat conditions here were strong in 2019. The site received an RBP score of 124 (Partially Supporting)—the same score as 2018. Scores for pool variability, channel flow conditions, and channel alterations contributed to this outcome. Habitat conditions in 2019 have been similar to the cumulative average score of 127 (Supporting), but lower than the three-year running average of 133 (Supporting).

Geomorphically, this reach has experienced some meaningful changes recently. The 2018 measurement shows that the channel filled with  sediment compared to the 2016 and 2015 measurements. The surrounding floodplain between the monuments also shows classic near channel aggradation associated with a high sediment supply system (Malanson 1993). The on-going impact of this sedimentation is unclear, but excessive sediment is known to decrease the occurrence of sensitive species in stream systems (Waters 1995). This aggradation has possibly contributed to the lowered BIBI score of 2018. Also observed here in 2018, was that the upstream portion of the site was beginning to become braided and expanding. It was due to this that a depression of water was found when extending the right monument, as portrayed by the graph below. The 2019 measurement is almost identical to the 2018 measurement, including the braiding and expansion observed the year before This reach classifies as a Rosgen E5 stream type.

HB-02 Cross Section Comparison 

Cross Section
Click to enlarge

Historical Data Summary:

HB-01
YearBIBI (Condition)FIBI (Condition)RPB (Condition)
20071.86 (VP)---110 (PS)
20082.43 (P)---116 (PS)
20092.14 (P)---120 (PS)
20102.71 (P)---138 (S)
20112.71 (P)---123 (PS)
20122.71 (P)---127 (S)
20132.43 (P)---119 (PS)
20142.71 (P)---131 (S)
20153.00 (P)2.33 (P)123 (PS)
20163.00 (P)2.33 (P)143 (S)
2017------138 (S)
20182.43 (P)3.00 (F)114 (PS)
20192.71 (P)--124 (PS)
HB-02
YearBIBI (Condition)FIBI (Condition)RBP (Condition)
20072.14 (P)---99 (NS)
20082.71 (P)---134 (S)
20092.71 (P)---115 (PS)
20103.57 (F)---134 (S)
20113.00 (F)---134 (S)
20122.14 (P)---136 (S)
20133.86 (P)---126 (S)
20142.14 (P)---117 (PS)
20153.00 (F)3.67 (F)125 (PS)
20163.29 (F)2.33 (P)144 (S)
20171.00 (VP)---140 (S)
20182.14 (P)2.33 (P)124 (PS)
20191.86 (CP)--124 (PS)
All Station Summary
 Average BIBI (SD)3-Year Average BIBI (SD)Average RPB (SD)3-Year Average RBP (SD)
HB-012.57 (0.33)2.57 (0.29)127 (10)132 (8)
HB-022.58 (0.75)2.07 (0.94)127 (12)133 (11)

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