Fixed-station water-quality monitoring at Fort Matanzas National Monument: 2012 data summary

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

doi:10.36967/2195211

In 2010 the National Park Service (NPS) Southeast Coast Network (SECN) Inventory and Monitoring Program began collecting water-quality data in the estuarine waters near Fort Matanzas National Monument (FOMA) as part the NPS Vital Signs monitoring program. The continuous-monitoring data station is located at the visitors center dock. This station collects pH, dissolved oxygen, temperature, salinity, specific conductance, turbidity and water-level data every 30 minutes. The FOMA fixed-station water-quality monitoring site is part of the SECN estuarine water-quality monitoring program, which routinely collects data in the vicinity of seven coastal parks located along the southeastern U.S. coast (DeVivo et al. 2008). Summary data are presented in annual data reports published by the SECN. Information collected by this monitoring program will be used to help managers make better-informed decisions by understanding trends and variability related to water-quality conditions in park waters. Findings for 2012 are as follows: Continuously-collected dissolved oxygen concentration data indicated good conditions, with the lowest monthly average level occurring in July (5.8mg/L). During the year there were no occurrences of the average daily value for dissolved oxygen dropping below 5 mg/L. Turbidity levels were generally low (<10 NTUs) throughout the year with no daily averages exceeding 35 NTUs. Monthly turbidly averages were highest in the summer, and did not exceed 14.6 NTUs. Salinity levels ranged from 26.96 to 38.57 parts per thousand (ppt) throughout the year, with monthly averages ranging from 34.9 in September to 36.9 in July. Periods of low salinity observed in July and September corresponded to periods of high rainfall and runoff during the preceding months. Mean monthly pH values ranged between 8.0 in August and September, and 8.4 in December. Monthly averages for water temperature ranged from 17.1ºC (62.8ºF) in February to 27.2ºC (81.0ºF) in July. Individual readings for water temperature ranged from 11.4ºC (52.5ºF) in January, to 30.4ºC (86.7ºF) in July. Discrete sampling of water clarity, nutrients, and chlorophyll a indicated fair to good conditions throughout the year. September was the only month were dissolved inorganic nitrogen levels rated fair; the rest of the year was rated as good. Eight of the 12 months rated fair levels for dissolved inorganic phosphorus; the other four months were rated as good. There were no poor results from any water clarity, nutrients, or chlorophyll a sampling in 2012. In 2012, roughly 10% of data were excluded from analysis because they were considered anomalous. Anomalous data was most commonly associated with problems with pH for a variety of reasons, primarily due to unknown sonde malfunctions or probe drift. Additionally, approximately 19 days of data were missing from January 26 to and February 14 due to loss of memory within the data sonde.

Fixed-station water-quality monitoring at Fort Matanzas National Monument: 2012 data summary

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