Water Quality at Timucuan Ecological and Historic Preserve:Baseline Data and Management ImplicationsEva DiDonato1, Guy DiDonato2, Amy Kalmbacher3, and Richard Bryant41National Park Service:Southeast Coast Network,2NOAA: Hollings Marine Laboratory,3Florida Department of Environmental Protection/Office of Coastal and Aquatic ManagedAreas,4National Park Service: Timucuan Ecological and Historic Preserve.BackgroundTidal creeks contain critical habitat for a variety of fish,and wildlife species. They serve as nursery habitats for fish,crustaceans, and shellfish and foraging habitat for birds andmammals while providing a multitude of recreationalopportunities including boating, fishing, and bird watching.Timucuan Ecological and Historic Preserve (TIMU),contains hundreds of miles of tidal creek habitat and coversapproximately 46,000 acres between the St. Johns River andthe Nassau River. The entire preserve is located withinDuval County and the city limits of Jacksonville, FL.Because of its location, TIMUfaces many anthropogenicthreats to water quality including contaminants fromagricultural, industrial, and residential land uses. In 2004,TIMU management teamed with the State of FloridaDepartment of EnvironmentalProtection to begin a longterm water quality monitoring program. In March 2004, awater-quality datalogger was deployed off of the KingsleyPlantation dock (Figure 1). This device recorded watertemperature, salinity, pH, dissolved oxygen, depth, andturbidity at half-hour intervals.Methods and ResultsData were collected beginning in March 2004, with a YSI 6600 multiparameter sonde unit. Methodsfor instrument calibration followed standard manufacturer protocols. Environmental variables(temperature, salinity, pH, dissolved oxygen, depth, and turbidity) were recorded every 30minutes. Sample collection and data analysis followed protocols established by the NationalEstuarine Research Reserve Program (Arendt et al., n.d.; Wenner et al., 2004).This analysisincludes data from March 2004 to March 2005.The water-quality datalogger was deployed on average 10.6 days between calibrations. The shortestfield deployment was 2 days (July 2004), whilethe longest was 24.8 days (January 2005). Shortdeployment times, especially during the warmerseasons, prevented significant fouling on theinstrument probes. In total, thedevice recorded nearly17,000 values for each parameter. Parameterresults include:•pH:pH ranged from 7.2 to 8.2 withvalues above 8.0 21% of the time.•Temperature:Water temperatures ranged from 9.7°C to 30.9°C. Temperatures exceeded 25°Cin 40% of the measurements.•Depth:Mean depth at this site was 4.0 m and showeda mean daily tidal range of 1.54 m. Theminimum recorded depth was 2.6 m (December), and the maximum was 5.4 m (November).•Turbidity:Minimum and maximum turbidities were 0.1 NTU and 1,860.2 NTU, respectively.Turbidity was greater than 25 NTU (i.e., the federal standard) approximately 3% of the time.•Salinity:Mean daily salinity was 29.4 ppt with the mean salinity range being 7.75 ppt. Thelowest salinity occurred in September immediately after Hurricane Francis(5.2 ppt) and the highestoccurred in March (35.9 ppt).•Dissolved Oxygen (DO):Minimum percent DO saturation observed was 5.4% (July) andhighest was 139.3% (January). Over the year, several hypoxic events (DO < 28%) were observed.These occurred primarily in Summer/Fall but wererare (up to 6% of deployment) and short (noneof these events lasted longer than 12 hours).2004-032004-042004-052004-062004-072004-082004-092004-102004-112004-122005-012005-02hypoxiasupersaturation012345678910hypoxiasupersaturation7.07.27.47.67.88.08.28.48.6 M a rc h 20 0 4 April 2004 M a y 200 4 June 2004 July 2004 August 2004 Se pt ember 2 0 04 O cto b er 2 00 4 Nov e m b e r 20 0 4 December 2004 J a n ua ry 2 00 5 Fe b ru a ry 2 0 0 5

pHMaximum10th %tileMean90th %tileMinimumDiscussionThese data provide baseline water-quality information for TIMUat the Kingsley Plantation site. As development pressuresadjacent to and within the preserve increase, baseline waterquality data like these will be crucial for making informedmanagement decisions aimed towards protecting this valuable resource.Water quality data collected in this study suggest that the tidal creeks near the Kingsley Plantation site are not well flushed.Creek pH (Figure 2) falls within a verynarrow range (7.2 – 8.2), suggesting a highly buffered system with limited freshwaterinput. After Hurricane Francis (September 5-7, 2004) passed through the area, salinity remained extremely variable untilDecember (Figure 3). This indicates that freshwater flushing of this system is slow, in this case, several months. Because of theprotracted flushing time within TIMU tidal creeks,preventingthe inflow of contaminantsand excess nutrients will beparamount to the long-term management and protection of Park water resources.There were several short hypoxic events recorded during this year of sampling (Figure 4). The majority of these incidentsoccurred during the summer period, which is very common for tidal creeks in this region. In fact, short hypoxic periods benefitthese valuable nursery habitats by creating a temporary refuge for small crustaceans and crabs from some predators. On theother hand, severe or long-lasting hypoxic events may indicate nutrient enrichment and eutrophication issues. Continuedmeasurement of dissolved oxygen inTIMU creeks can be a useful indicator of environmental degradation.ReferencesArendt, M., Snoots, T., and Chen, Y., n.d.A Manual Demonstrating use of MS Access and MS Excel for Synthesizing Water Quality Datafrom the NERR System-Wide Monitoring Program. South Carolina Department of Natural Resources, 34p.Wenner, E., Sanger, D., Arendt,M., Holland, A.F., and Chen, Y., 2004. Variability in Dissolved Oxygen and Other Water-QualityVariables Within the National Estuarine Research Reserve System.Journal of Coastal Research, 45, 17-38.AcknowledgementsWe would like to thank Fred Holland and Chris Buzzelli for theirassistance with data interpretation, Laurie Clarke, KellyMorgan, and Pamela Chancey for their field assistance, Rick Gleeson and Jon Brucker for their technical assistance, Joe DeVivoand Mike Byrne for their constructive editorial suggestions, and Sara McCort and Chris Saylor fortheir assistance with mapping.Figure 2. Monthly Summary of pH at KingsleyPlantation Site.Figure 4. Hypoxia and Supersaturation events atKingsley Plantation Site.h

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H a n n a h M i l l s C r .Round Pond F o r t G e o r g e I n l e tTimucuan EHPKingsley Datasonde Areaμ Map created by the Old Growth Bottomland Forest Research and Education CenterTimucuan EHPAtlanticOceanSoutheast Coast NetworkNational Park ServiceU.S. Department of the InteriorVicinity MapMap ExtentLegend303(d) Waters0 10.5 Mi.Kingsley DatasondehFigure 1. Timucuan Ecological and Historic Preserve,Kingsley Plantation Site.00.005.010.015.020.025.030.035.040.0 3/1/2004 4/1/2004 5/1/2004 6/1/2004 7/1/2004 8/1/2004 9/1/2004 10/1/2004 11/1/2004 12/1/2004 1/1/2005 2/1/2005Sal (ppt)Figure 3. Salinity Data from KingsleyPlantation Site.