Waterbody: Northeast Black Creek 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. Basin: Bird Sink Due to ongoing beaver activity, station BC1 is no Northeast Black Creek is a tannic, acidic, predomi- longer sampled. Leon County staff continue to nantly nitrogen-limited stream located in northeast- evaluate the hydrological and plant community ern Leon County. The stream forms near Centerville changes that are occurring in this section. Road and the Chemonie Plantation subdivision and Methods flows southeast through the Miccosukee Land Coop- erative before crossing under Capitola Road. The Surface water samples were collected to determine creek then turns northeast to join Still Creek and then the health of Northeast Black Creek and met the re- flows into Bird Sink. quirements of the Florida Department of Environ- mental Protection (FDEP). As shown in the following pie chart, approximately 31% of the 15,783-acre watershed is comprised of Results urban, agriculture/rangeland, transportation and utilities land uses. Increases in stormwater runoff and Nutrients waterbody nutrient loads can often be attributed to According to FDEP requirements, four temporally in- these types of land uses. 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 NNC (based on a geometric mean) has never been ex- ceeded during the period of record. For illustrative purposes, individual data points were plotted to de- termine any possible trends (Figures 1 and 2). With few exceptions, individual values did not exceed the instream criteria for total phosphorus or total nitro- gen. Table 1. FDEP’s total phosphorus criteria for streams applied to North- (e.g., improperly functioning septic tanks). Other east Black Creek. Due to conditions not suitable for sampling, the state numeric nutrient criteria data requirements could not always be calcu- causes could be wild animals and/or agriculture. lated for stations during the period of record. Northeast Instream Protection Criteria TP Dissolved Oxygen Black (0.18 mg/L) Creek As Figure 4 shows, Northeast Black Creek stations oc- Year BC1 BC2M BC3 BC4 casionally did not meet the Class III criteria for dis- 2006 - - - - solved oxygen (DO). Staff believes that this is a natural 2007 0.18 - - - condition for this location, since the creek is a low gra- 2008 - - - dient blackwater stream that drains wetlands. 2009 0.08 - 0.07 0.06 2010 0.08 - - - Biochemical Oxygen Demand (BOD) 2011-2012 - - - - 2013 0.08 0.09 0.07 0.07 BOD levels were elevated at stations BC2M (6.8 mg/L) 2014 - - - - and BC3 (3.1 mg/L) during the 2nd quarter sampling 2015 - - 0.06 - event in 2019. Other water quality parameters taken 2016-2017 - - - - at that time were typical of the stream, so it is un- 2018 - - 0.07 0.03 known why the BOD levels were elevated. 2019 - - - - Biology 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 Stream Condition Index and Habitat Assessment for stations during the period of record. Northeast Instream Protection Criteria TN The Stream Condition Index (SCI) sampling is not per- Black (1.03 mg/L) formed every year, so the following results are from Creek 2018. Year BC1 BC2M BC3 BC4 2006 0.36 - - - The SCI scores for stations BC2M (69) and BC4 (69) 2007 - - - - were in the Exceptional range, while station BC3 (56) 2008 - - - - was in the healthy range (Table 3). The Habitat As- 2009 0.27 - 0.69 0.72 sessment Scores for stations BC2M (127), BC3 (134) 2010 0.41 - - - 2011-2012 - - - - and BC4 (106) ranged from Suboptimal to Optimal 2013 0.40 0.71 0.61 0.47 (Table 4). 2014 - - - - 2015 - - 0.66 - Station BC2M 2016-2017 - - - - The results of the Habitat Assessment score for Black 2018 - - 0.64 0.68 Creek BC2M characterize the stream habitat between 2019 - - - - the high suboptimal to low optimal categories, with Escherichia coli (E. coli) the score being influenced by substrate availability and areas with high bank angles, particularly in the The E. coli water quality limit of > 410 in 10% of sam- bends. ples collected over a thirty-day period was exceeded several times at stations BC2M, BC3 and BC4 (Figure Due to low rainfall, the upper section of Black Creek 3) but only once in 2018 at station BC2M and not was reduced to segments of dry channel with few exceeded in 2019. Based on anthropogenic land use, pools during much of late 2017 and the first half of FDEP considers the exceedances are possibly the 2018. Dry conditions would normally lead to lower SCI result of residential development in the watershed scores, however, considering the SCI results, this stream sometimes exhibits slow flowing pools during The macroinvertebrate community at BC4 was domi- dry periods, with water moving in the channel below nated by the chironomid Polypedilum aviceps and rif- the substrate between pools. The SCI score and fle beetles (Elmidae). From the total taxa collected, substantial taxa richness (53 taxa) indicates the nine are listed as sensitive taxa by the FDEP while five stream landscape setting is conducive to rapid are listed as very tolerant. Two Ephemeropteran spe- recruitment of lotic taxa once sustained flow returns cies were collected including the “sensitive” species after dry periods. The presence of the Ephemeroptera Maccaffertium smithae. The Trichoptera were repre- (mayflies) Maccaffertium mexicanum further sented by five species including two species of the demonstrates the creek’s dry periods. Maccaffertium “sensitive” genus Triaenodes. Also, of note is the mexicanum is noted to inhabit streams with routine, presence of a single specimen of a Trichopteran taxa distinct spring dry periods that preclude the presence identified in the taxonomy list as Rhyacophila near of the similar Maccaffertium exiguum, which requires lobifera. This specimen is not R. lobifera, but the most nearly continuous flow. recent key uses near R. lobifera because the larvae cannot presently be separated from the true R. lobif- From the total taxa collected, seven are listed as sen- era using published literature. Dr. Rasmussen noted sitive taxa by the FDEP while four are listed as very in the Identification Manual for the Caddisfly (Tri- tolerant. The Ephemeroptera (mayflies), Plecoptera choptera) Larvae of Florida (2004), that the R. lobifera (stoneflies) and Trichoptera (caddisflies) taxa (EPT) like Rhyacophila from Black Creek is in fact a new spe- are widely regarded as the groups of aquatic insects cies that is soon to be described. Within Florida, it has that contain a large number of pollution sensitive been found at one other stream system, also in Leon taxa. Two Ephemeropteran species were collected in- County. The same new species is also presently Maccaffertium mexi- cluding the “sensitive” species known from blackwater coastal plain streams in canum . The Trichoptera were represented by two North and South Carolina. In North Carolina it is noted species. No Plecoptera were noted in the SCI. as “significantly rare”. No Plecoptera were noted in Station BC3 the SCI. The results of the Habitat Assessment score for Black Other Parameters Creek BC3 characterize the stream habitat as optimal, Other water quality parameters appear to be normal with the score being influenced mainly by substrate for the area and no impairments were noted. availability. Conclusions From the total taxa collected, six are listed as sensitive taxa by the FDEP while nine are listed as very tolerant. Based on ongoing sampling, Northeast Black Creek One Ephemeropteran species was collected, the “sen- met the nutrient thresholds for the East Panhandle sitive” genus Leptophlebia. The Trichoptera were rep- Region. Occasionally the stations did not meet the resented by four species, including the “sensitive” ge- Class III criteria for DO. This is the result of normally nus Triaenodes. No Plecoptera were noted in the SCI. low DO in low gradient, wetland fed systems like this stream. The E. coli water quality limit was exceeded Station BC4 several times since sampling began but was not The results of the Habitat Assessment score for Black exceeded in 2019. Residential development in the Creek BC4 characterize the stream habitat as subop- watershed could result in elevated nutrients. BOD timal, with the score being influenced by man-made levels were elevated at stations BC2M and BC3 during nd modified channel morphology in the lower portion of the 2 quarter sampling event in 2019. Other water the sampling transect. quality parameters taken at that time were typical of the stream, so it is unknown why the BOD levels were Contact and resources for more information elevated. www.LeonCountyWater.org The 2018 SCI scores for stations BC2M and BC4 were in the exceptional range, while station BC3 was in the Click here to access the results for all water quality healthy range. The Habitat Assessment Scores for sta- stations sampled in 2019. tions BC2M, BC3 and BC4 ranged from Suboptimal to Click here for a map of the watershed – Sample Sta- Optimal.