Fixed-station water-quality monitoring at Cumberland Island National Seashore: 2015–2016 data summary

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 of the NPS Vital Signs monitoring program. The continuous-monitoring 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 network. 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. Summary findings below are based on continuous data and discrete sampling collected during 1 January 2015–31 December 2016. • Continuous data were collected at one fixed-station site by the Southeast Coast Network. • Mean monthly dissolved oxygen levels were generally good throughout the entire year, ranging from a low of 5.6 mg/L in September 2015 to a high of 8.9 mg/L in March 2015. Individual dissolved oxygen readings ranged from 3.6 mg/L in May 2015 to 11.2 mg/L in March 2015. • Mean monthly pH values ranged from a low of 7.9 in multiple months to a high of 8.1 in multiple months. Individual pH readings ranged from 7.6 in to 8.2 in multiple months. • Monthly mean turbidity values ranged from 5.8 NTU in November 2015 to 10.4 NTU in February 2016. Individual turbidity readings ranged from 0.7 NTUs in July 2015 to 67.5 NTUs in October 2016. • Mean monthly water temperatures ranged from 14.2ºC (57.6 ºF) in February 2015 to 30.1 ºC (86.2 ºF) in July 2016. Individual temperature readings ranged from 10.7 ºC (51.3 ºF) in February 2015 to 32.4 ºC (90.3 ºF) in July 2016. • The tidal range for the Fort Matanzas National Monument site was approximately 3.0 meters (9.8 feet).