Georgia coastal waters are home to commercially and recreationally important species such as fish, shrimp, crabs and oysters as well as the smaller organisms on which they feed. They are also important areas for nutrient cycling and the treatment of waste and runoff. The condition of our coastal waters affects fishing and shellfishing as well as other human uses of the coast, such as boating and swimming. The Coastal Resources Division of the Georgia Department of Natural Resources (GA-DNR CRD) collects water quality data in support of a variety of programs. These programs measure different water quality and resource parameters in order to meet diverse goals, and data from them had not previously been integrated or analyzed in a common framework. The data also had not been evaluated with the goal of identifying those measurements that might be useful indicators of the status of Georgia coastal waters. This project was designed to compile coastal water quality data collected by GA-DNR CRD into an integrated database and to identify an appropriate suite of indicator parameters for Georgia waters.
The Condition of Georgia’s Coastal Waters: Development and Analysis of Coastal Water Quality Indicators
We obtained data from CRD for four monitoring programs (river nutrients, sound nutrients, shellfish water quality, and beach water quality) and compiled all the data into a common SQL Server database. 185 sites are represented, with some measurements spanning the years 1998-2009 but most, including nutrient observations, spanning 2000-2006. For 76 sites with continuous data from 2000-2006, we found that temporal patterns have been fairly uniform across the spatial domain, and these patterns appear to be linked to patterns of freshwater input: a drought in 1998-2002 was followed by a wet 2003, then more moderate rainfall and another drought from 2006-2009. Nutrient (ammonia, nitrite, nitrate, phosphate, total dissolved phosphorus (TDP)) concentrations generally rose in late 2002 as the drought broke, then fell in 2003, when there was a pronounced decline in dissolved oxygen (DO) to <4 mg L-1 for many sites.
We proposed a suite of seven indicators and recommended criteria intended to help classify and understand the causes of water quality degradation in Georgia. These included both “immediate” indicators of poor water quality (pH, DO) as well as “early warning” indicators of potentially poor water quality (total dissolved nitrogen (TDN), TDP, chlorophyll a, transparency, biochemical oxygen demand (BOD)). Specific recommendations for the criteria to be used to classify each of these seven indicators as “good”, “fair”, or “poor” are summarized in Chapter 5 of the technical report.
We used the CRD data to assess the status of Georgia estuaries and coastal waters in terms of pH, DO, and nutrients, according to our recommended criteria. (At the present time we do not have data to assess chlorophyll a and BOD, and the turbidity data collected by CRD are not directly relatable to the recommended transparency criteria.) CRD measured TDP but only the inorganic fraction (DIN: nitrate, nitrite, ammonia) of TDN, so interim DIN criteria are expressed as a fraction of TDN criteria. Annual minimum pH was poor in blackwater streams in 2004 but improved in 2006. Annual minimum DO was low and median DO was fair coastwide in 2003, but conditions improved by 2006. Annual median DIN was mostly fair coastwide each year, with poor sites concentrated in Altamaha River estuary, and annual median TDP was fair at all sites throughout the study period.
The report includes a series of recommendations regarding CRD’s water quality programs, including continued monthly monitoring of the parameters outlined in the indicators suite. Our primary recommendations are as follows: CRD should add chlorophyll a and BOD5 to the core monitoring programs; switch its nutrient monitoring from a focus on inorganic nutrients to total dissolved (TDN and TDP), with the particulate fraction (PN and PP) included to be able to be in compliance with expected national directives; switch from turbidity measurements to a measure of transparency, such as % light transmission or Secchi depth; and continue measurements of dissolved oxygen, pH, and ancillary data (salinity, specific conductance and water temperature).
This technical report is available in full or as individual chapters:
1. Introduction
3a. Trends
3b. Trend Maps
4. Correlations
5. Indicators
6. Status
8. References
Joan E. Sheldon and Merryl Alber. 2010. The Condition of Georgia’s Coastal Waters: Development and Analysis of Water Quality Indicators. Technical report prepared by the Georgia Coastal Research Council, University of Georgia, Athens GA for the Georgia Department of Natural Resources, Coastal Resources Division, 173 pp.
Other Publications:
Georgia Coastal Water Quality 2000-2006
The Coastal Resources Division (CRD) of the Georgia Department of Natural Resources (GA DNR) collects water quality data in support of a variety of programs. The Georgia Coastal Research Council recently compiled these observations into an integrated database and analyzed it for long-term and seasonal trends. As a part of that effort, we proposed a suite of indicators and recommended evaluation criteria intended to help classify and understand the causes of water quality degradation in Georgia. In this brochure we use the GA DNR CRD data to assess the status of Georgia estuaries and coastal waters according to the criteria recommended for the first four of these indicators: dissolved oxygen, nitrogen, phosphorus, and pH.
Joan E. Sheldon and Merryl Alber. 2011. Georgia Coastal Water Quality 2000-2006. Report by the Georgia Coastal Research Council, University of Georgia, Athens GA for the Georgia Department of Natural Resources, Coastal Resources Division, 15 pp.
Georgia Coastal Water Quality 2000–2010
The Coastal Resources Division (CRD) of the Georgia Department of Natural Resources (GA DNR) collects water quality data in support of a variety of programs. The Georgia Coastal Research Council has compiled these observations into an integrated database and analyzed them for long-term and seasonal trends. As a part of that effort, we proposed a suite of indicators and recommended evaluation criteria intended to help classify and understand the causes of water quality degradation in Georgia. These indicators, which are described in a separate technical report (Sheldon and Alber 2010), are dissolved oxygen, nitrogen, phosphorus, pH, chlorophyll a, transparency, and biochemical oxygen demand. We also developed a brochure (Sheldon and Alber 2011) in which we used the GA DNR CRD data to assess the status of Georgia estuaries and coastal waters for 2000-2006 according to the criteria recommended for the first four of these indicators, as these are the only ones for which information was available. This report is an update to that effort and incorporates data collected through mid-2010. Since then, water quality samples have been processed by the GA Environmental Protection Division (EPD) using a different laboratory, and so the data may not be comparable to the earlier work. It is our hope that assessments of all seven of these indicators will be conducted on a regular basis in the future in order to provide ongoing information on the status of Georgia’s estuarine and coastal waters.
Joan E. Sheldon and Merryl Alber. 2013. Georgia Coastal Water Quality 2000-2010. Report by the Georgia Coastal Research Council, University of Georgia, Athens GA for the Georgia Department of Natural Resources, Coastal Resources Division, 21 pp.
Recommended Indicators of Estuarine Water Quality for Georgia
Increasing nutrient input and subsequent eutrophication and hypoxia are concerns in many estuaries, and the U.S. EPA has mandated the development of numeric nutrient criteria to assess the status of U.S. coastal waters. However, they recognize the need for regionally appropriate criteria, as previous national-level efforts have often relied on criteria that are not equally relevant in all waters. Two pathways to eutrophication have been suggested to exist in Georgia waters: the classic phytoplankton- mediated pathway in stratified waters and an alternate pathway in which excess nutrients stimulate microbial respiration directly, resulting in low dissolved oxygen throughout a well-mixed water column. We propose a suite of seven indicators, as well as basic ancillary data (water temperature, salinity, specific conductance), that are intended to help classify and understand the causes of water quality degradation in Georgia. We recommend two immediate indicators of poor water quality (pH and dissolved oxygen) that may indicate that a stressful and potentially lethal condition is already in progress. The remaining five (nitrogen, phosphorus, chlorophyll a, transparency, and biochemical oxygen demand (BOD)) are “early warning” indicators of potentially poor water quality that should be measured in order to anticipate problems and make appropriate management decisions. These indicators, which cover the progression of eutrophication from nutrient over-enrichment to algal overgrowth (if present) to enhanced microbial respiration and hypoxia, will help to ensure that problems will not be missed due to limited sampling frequencies. We present the rationale for choosing these indicators and the considerations for developing evaluation criteria.
Joan E. Sheldon and Merryl Alber. 2011. Recommended Indicators of Estuarine Water Quality for Georgia. Proceedings of the 2011 Georgia Water Resources Conference, April 11-13, 2011, University of Georgia.
Water Quality Status of Georgia Estuaries and Coastal Waters Using Recommended Indicators
Water quality is a concern in many estuaries, and the U.S. EPA has mandated the development of numeric nutrient criteria to assess the status of U.S. coastal waters. We have proposed a suite of seven indicators that are intended to help classify and understand the causes of water quality degradation in Georgia by covering the progression of eutrophication from nutrient over-enrichment to algal overgrowth (if present) to enhanced microbial respiration and hypoxia. Of these, we are able to assess four indicators coastwide using data collected by GA DNR CRD during 2003-2006. pH status was assessed using ΔpH, the deviation from the expected pH according to the sample salinity and estuary type (alluvial/tidewater, blackwater, alkaline blackwater). Annual median pH deviations were classified as good at almost all sites in all years, whereas annual minimum pH deviations often ranged into the fair and poor categories. pH status generally improved from 2004 to 2006. Annual median dissolved oxygen (DO) was mainly good to fair, while annual minimum DO was mainly fair to poor, with sites classified as poor occurring sporadically along the coast. DO status generally improved from 2003 to 2006. Annual median dissolved inorganic nitrogen status was mostly fair coastwide in all years, with the few sites classified as poor concentrated in the Altamaha River estuary. Annual median total dissolved phosphorus was fair coastwide during the study period. The generally poorer water quality in 2003 compared to later years may have been due to conditions related to high rainfall after a severe drought.
Merryl Alber and Joan E. Sheldon. 2011. Water Quality Status of Georgia Estuaries and Coastal Waters Using Recommended Indicators. Proceedings of the 2011 Georgia Water Resources Conference, April 11-13, 2011, University of Georgia.