Fixed-station water quality monitoring at Timucuan Ecological and Historic Preserve: 2011 data summary.

Wright, Wendy; Gregory, M.; Rinehart, Aaron

doi:10.36967/2190462

In 2003 the Northeast Florida Water Quality Preservation Group — a coalition composed of the Florida Department of Environmental Protection, Office of Coastal and Aquatic Managed Areas (CAMA), the National Park Service (NPS), and the Nature Conservancy — was formed by official Memorandum of Understanding to “collaborate to preserve, protect, and enhance water quality” of Timucuan Ecological and Historical Preserve (TIMU) in northern Florida. In 2006, the National Park Service Southeast Coast Network (SECN) in cooperation with the City of Jacksonville, Florida and CAMA established a jointly-operated water quality monitoring network within the Preserve’s boundaries to provide relevant water quality information to resource managers locally and at TIMU. This network is currently composed of 16 sites — 12 of which are monitored every other month by the City of Jacksonville for nutrients and chlorophyll a with four additional sites monitored continuously by the NPS for pH, dissolved oxygen, temperature, salinity, specific conductance, turbidity and water level. Information collected by this monitoring program will be used to help managers make informed decisions by understanding trends and variability related to water-quality conditions in park waters. Continuous data records presented at the four monitoring stations reflect only 6 months of data collection during 2011. Continuous data collection activities were suspended in June due to closing of the Florida Department of Environmental Protection, Office of Coastal and Aquatic Managed Areas (CAMA). Elevated levels of dissolved phosphorus were the most common cause of poor waterquality ratings during 2011. Discrete bimonthly water-quality sampling indicated elevated phosphorus (TDP) levels at all sites sampled in TIMU. High levels of phosphorus were more common during the late summer months at most sites although TIM1 and TIM2, the most upstream sites on the Nassau River, exhibited elevated levels throughout the year. Except for poor water clarity conditions observed on a single date in April at TIM1, water clarity, chlorophyll a, dissolved oxygen, and dissolved inorganic nitrogen levels rated as either good or fair throughout the year. Dissolved oxygen levels generally decreased from January to June at all sites as water temperatures increased. Mean daily dissolved oxygen levels below 5mg/L were commonly observed at all of the sites through June. Mean daily dissolved oxygen levels below 2 mg/L were occasionally observed at both the Clapboard Creek and Nassau River Stations during late spring. Salinity levels dipped to their lowest points during March at all sites although the freshwater influence was least discernible at Kingsley Plantation and the most pronounced at the Nassau River station. Lower salinity levels were observed for longer periods of the year at the more inland stations on Nassau River and Clapboard Creek. The Nassau River station became dominated by freshwater during early spring months. pH values were consistently lower at the Nassau River site throughout the spring with the lowest pH values at the Nassau River station coinciding with periods of high streamflow.

Fixed-station water quality monitoring at Timucuan Ecological and Historic Preserve: 2011 data summary.

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