Waterbody: Northeast Black Creek

Basin: Bird Sink

Northeast Black Creek is a tannic, acidic, predomi-nantly nitrogen-limited stream located in northeast-ern Leon County. The stream forms near Centerville Road and the Chemonie Plantation subdivision and flows southeast through the Miccosukee Land Coop-erative before crossing under Capitola Road. The creek then turns northeast to join Still Creek and then flows into Bird Sink.

As shown in the following pie chart, approximately 31% of the 15,783 acre watershed is comprised of res-idential, agriculture/rangeland, transportation and utilities land uses. Increases in stormwater runoff and waterbody nutrient loads can often be attributed to these types of land uses.

Background

Healthy, well-balanced stream communities may be maintained with some level of human activity, but ex-cessive human disturbance may result in waterbody degradation. Human stressors may include increased inputs of nutrients, sediments, and/or other contam-inants from watershed runoff, adverse hydrologic al-terations, undesirable removal of habitat or riparian buffer vegetation, and introduction of exotic plants and animals. Water quality standards are designed to protect designated uses of the waters of the state (e.g., recreation, aquatic life, fish consumption), and exceedances of these standards are associated with interference of the designated use. Due to ongoing beaver activity, station BC1 is no longer sampled. Leon County staff continues to evaluate the hydrolog-ical and plant community changes that are occurring in this section.

Methods

Surface water samples were collected to determine the health of Northeast Black Creek and met the re-quirements of the Florida Department of Environ-mental Protection (FDEP).

Results

Nutrients

According to FDEP requirements, four temporally in-dependent samples per year are required to be col-lected to fulfill data requirements for the Numeric Nutrient Criteria (NNC) thresholds. Unfortunately, due to stagnant streamflow conditions not suitable for sampling, collecting the amount of data required by FDEP has been difficult (Tables 1 and 2). The nutri-ent thresholds and results are found in Table 1. The NNC has never been exceeded during the period of record.

Table 1. FDEP’s total phosphorus criteria for streams applied to North-east Black Creek. Due to conditions not suitable for sampling, the state numeric nutrient criteria data requirements could not always be calcu-lated for stations during the period of record.

East Black Creek

Instream Protection Criteria TP (0.18 mg/L)

Year BC1 BC2M BC3 BC4 2006 - - - - 2007 0.18 - - - 2008 - - - 2009 0.08 - 0.07 0.06 2010 0.08 - - - 2011-2012 - - - -

2013 0.08 0.09 0.07 0.07 2014 - - - - 2015 - - 0.06 - 2016-2017 - - - -

2018 - - 0.07 0.03

Table 2. FDEP’s total nitrogen criteria for streams applied to Northeast Black Creek. Due to conditions not suitable for sampling, the state nu-meric nutrient criteria data requirements could not always be calculated for stations during the period of record.

East Black Creek

Instream Protection Criteria TN (1.03 mg/L)

Year BC1 BC2M BC3 BC4 2006 0.36 - - - 2007 - - - - 2008 - - - - 2009 0.27 - 0.69 0.72 2010 0.41 - - - 2011-2012 - - - -

2013 0.40 0.71 0.61 0.47 2014 - - - - 2015 - - 0.66 - 2016-2017 - - - -

2018 - - 0.64 0.68

Escherichia coli (E. coli)

The E. coli water quality limit of > 126 in 10% of sam-ples collected over a 30 day period and the > 410 in 10% of samples collected over a thirty day period was exceeded several times at stations BC2M, BC3 and BC4 (Figure 1) but only once in 2018 at station BC2M.

Residential development in the watershed could re-sult in elevated nutrient levels and incidence of fecal coliforms (due to improperly functioning septic tanks). Other causes could be wild animals and/or ag-riculture.

Dissolved Oxygen

As Figure 2 shows, Northeast Black Creek stations oc-casionally did not meet the Class III criteria for dis-solved oxygen (DO). Staff believes that this is a natural condition for this location, since the creek is a low gra-dient blackwater stream that drains wetlands.

Biology

Stream Condition Index and Habitat Assessment

The Stream Condition Index (SCI) scores for stations BC2M (69) and BC4 (69) were in the exceptional range, while station BC3 (56) was in the healthy range (Table 3). The Habitat Assessment Scores for stations BC2M (127), BC3 (134) and BC4 (106) ranged from Suboptimal to Optimal (Table 4).

Station BC2M

The results of the Habitat Assessment score for Black Creek BC2M characterize the stream habitat between the high suboptimal to low optimal categories, with the score being influenced by substrate availability and areas with high bank angles, particularly in the bends.

Due to low rainfall, the upper section of Black Creek was reduced to segments of dry channel with few pools during much of late 2017 and the first half of 2018. Dry conditions would normally lead to lower SCI scores, however, considering the SCI results, this stream may exhibit slow flowing pools during dry pe-riods, with water moving in the channel below the substrate between pools. The SCI score and substan-tial taxa richness (53 taxa) indicates the stream land-scape setting is conducive to rapid recruitment of lo-tic taxa once sustained flow returns after dry periods. The presence of the Ephemeroptera (mayflies) Mac-caffertium mexicanum further demonstrates the

creek’s dry periods. Maccaffertium mexicanum is noted to inhabit streams with routine, distinct spring dry periods that preclude the presence of the similar Maccaffertium exiguum, which requires nearly con-tinuous flow.

From the total taxa collected, seven are listed as sen-sitive taxa by the FDEP while four are listed as very tolerant. The Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies) taxa (EPT) are widely regarded as the groups of aquatic insects that contain a large number of pollution sensitive taxa. Two Ephemeropteran species were collected in-cluding the “sensitive” species Maccaffertium mexi-canum. The Trichoptera were represented by two species. No Plecoptera were noted in the SCI.

Station BC3

The results of the Habitat Assessment score for Black Creek BC3 characterize the stream habitat as optimal, with the score being influenced mainly by substrate availability.

From the total taxa collected, six are listed as sensitive taxa by the FDEP while nine are listed as very tolerant. One Ephemeropteran species was collected, the “sen-sitive” genus Leptophlebia. The Trichoptera were rep-resented by four species, including the “sensitive” genus Triaenodes. No Plecoptera were noted in the SCI.

Station BC4

The results of the Habitat Assessment score for Black Creek BC4 characterize the stream habitat as subop-timal, with the score being influenced by man-made modified channel morphology in the lower portion of the sampling transect.

The macroinvertebrate community at BC4 was domi-nated by the chironomid Polypedilum aviceps and rif-fle beetles (Elmidae). From the total taxa collected, nine are listed as sensitive taxa by the FDEP while five are listed as very tolerant. Two Ephemeropteran spe-cies were collected including the “sensitive” species Maccaffertium smithae. The Trichoptera were

represented by five species including two species of the “sensitive” genus Triaenodes. Also of note is the presence of a single specimen of a Trichopteran taxa identified in the taxonomy list as Rhyacophila near lobifera. This specimen is not R. lobifera, but the most recent key uses near R. lobifera because the larvae cannot presently be separated from the true R. lobif-era using published literature. Dr. Rasmussen noted in the Identification Manual for the Caddisfly (Tri-choptera) Larvae of Florida (2004), that the R. lobifera like Rhyacophila from Black Creek is in fact a new spe-cies that is soon to be described. Within Florida, it has been found at one other stream system, also in Leon County. The same new species is also presently known from blackwater coastal plain streams in North and South Carolina. In North Carolina it is noted as “significantly rare”. No Plecoptera were noted in the SCI.

Other Parameters

Other water quality parameters appear to be normal for the area and no impairments were noted.

Conclusions

Based on ongoing sampling, Northeast Black Creek met the nutrient thresholds for the East Panhandle Region. Northeast Black Creek stations occasionally did not meet the Class III criteria for DO. This is the result of normally low DO in low gradient, wetland fed systems like this stream. The E. coli water quality limit was exceeded several times since sampling began. Residential development in the watershed could re-sult in elevated nutrient levels and incidence of coli-forms (due to improperly functioning septic tanks) in the naturally shallow stream. Other causes could be wild animals and/or agriculture. The SCI scores for stations BC2M and BC4 were in the exceptional range, while station BC3 was in the healthy range. The Habi-tat Assessment Scores for stations BC2M, BC3 and BC4 ranged from Suboptimal to Optimal.

Other water quality parameters appear to be normal for the area and no other impairments were noted.

Thank you for your interest in maintaining the quality of Leon County’s water resources. Please feel free to contact us if you have any questions.

Contact and resources for more information

www.LeonCountyFL.gov/WaterResources

Click here to access the results for all water quality stations sampled in 2018.

Click here for a map of the watershed – Sample Sta-tions BC2M, BC3 and BC4.

Click here for a map of all of the watersheds

Johnny Richardson, Water Resource Scientist (850) 606-1500Richardsonjo@leoncountyfl.gov

Figure 1. E. coli results for Northeast Black Creek.

Figure 2. Dissolved Oxygen Percent Saturation results for Northeast Black Creek. Table 3. Stream Condition Index results for East Black Creek.

East Black Creek BC2M Rep 1

BC2M Rep 2

BC3 Rep 1

BC3 Rep 2

BC4 Rep 1

BC4 Rep 2

Stream Condition Index Metrics Scores Total Taxa 7.39 10.00 4.35 6.52 10.00 8.70 Ephemeroptera Taxa 2 2 2 0 4 4 Trichoptera Taxa 1.43 2.86 5.71 2.86 5.71 4.29 % Filter Feeder 10 9.44 9.43 8.06 2.46 2.91 Long-lived Taxa 3.33 3.33 3.33 3.33 6.67 3.33 Clinger Taxa 5.00 7.50 7.50 6.25 5.00 5.00 % Dominance 8.82 8.83 7.01 8.15 8.68 9.51 % Tanytarsini Taxa 9.21 10.00 2.73 6.26 7.48 8.70 Sensitive Taxa 6 5 5 5 9 7 % Tolerant Taxa 6.40 5.99 4.14 3.71 5.83 5.21 SCI Vial Score 66.20 72.17 56.90 55.70 72.03 65.17 Stream Condition Index Score 69 56 69 Score Interpretation Exceptional Healthy Exceptional

Table 4. Habitat Assessment results for East Black Creek.

East Black Creek BC2M Score

Category BC3 Score

Category BC4 Score

Category

Substrate Diversity 12 Suboptimal 16 Optimal 12 Suboptimal Substrate Availability 8 Marginal 9 Marginal 8 Marginal Water Velocity 20 Optimal 17 Optimal 11 Suboptimal Habitat Smothering 15 Suboptimal 14 Suboptimal 12 Suboptimal Artificial Channelization

20 Optimal 20 Optimal 14 Suboptimal

Bank Stability 7, 7 Suboptimal, Suboptimal

10, 10 Optimal, Optimal

6, 7 Suboptimal, Suboptimal

Riparian Zone Width 10, 10 Optimal, Optimal

10, 10 Optimal, Optimal

9, 9 Optimal, Optimal

Riparian Vegetation Quality

9, 9 Optimal, Optimal

9, 9 Optimal, Suboptimal

9, 9 Optimal, Optimal

Final Habitat Assessment Score

127 134 106

Interpretation Optimal/Suboptimal Optimal Suboptimal