Fixed-station water-quality monitoring at Timucuan Ecological and Historic Preserve: 2012 data summary

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

doi:10.36967/2195323

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 Historic 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 13 sites — 12 of which are monitored every other month by the City of Jacksonville for nutrients and chlorophyll a with one additional site monitored continuously by the SECN for pH, dissolved oxygen, temperature, salinity, specific conductance (to compute salinity) , turbidity and water level. Fixed-station water-quality monitoring at TIMU is part of the SECN Inventory & Monitoring Program, which routinely collects data at seven coastal parks located along the southeastern U.S. coast. Summary findings below are based on continuous data and bimonthly discrete sampling collected between January 1 and December 31 2012. Salinity levels at Kingsley Plantation dipped to their lowest levels of 12.5 ppt in late June in response to the nearly 16 inches of rain that fell during Tropical Storm Debby. The average monthly high was 36.3 ppt in May, and the average monthly low was 30.2 ppt in July. pH values were consistent throughout the year with monthly averages ranging from 7.9 to 8.1. The lowest pH readings also coincided with Tropical Storm Debby in late June. Turbidity values were generally low throughout the year with the highest monthly average of 9.3 NTUs in June, and the highest individual reading of 104.9 NTUs in November. Water temperature throughout the year was consistent with previous years. The lowest monthly average was 16.5°C (61.7°F) in February, and the highest monthly average was 29.1°C (84.38°F) in July. In 2012, 39% of continuous monitoring data were missing or considered anomalous and were not considered in analysis. In December of 2012, the sonde mount was determined to be compromised to a point where accurate collection of dissolved oxygen data was not possible. Because it could not be determined when this occurred, all dissolved oxygen data collected in 2012 were flagged as suspect. Elevated levels of orthophosphate (Dissolved Inorganic Phosphate / DIP) were the most common cause of poor water-quality ratings during 2012. Discrete bimonthly water-quality sampling indicated elevated DIP levels at all sites sampled in TIMU in March, and all but three sites in October. High levels of orthophosphate were recorded for every sample taken at TIM1 and TIM2, the most upstream sites on the Nassau River. Chlorophyll a, dissolved oxygen (when measured during discrete nutrient sampling), and dissolved inorganic nitrogen levels rated as either good or fair throughout the year. Water clarity rated good for all but three samples during 2012. TIM1 in June was fair along with TIM2 in October. The only poor water-clarity reading was at TIM6 in January.

Fixed-station water-quality monitoring at Timucuan Ecological and Historic Preserve: 2012 data summary

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