Scientific 

 Characterization 



Scientific data are used during the characterization phase as the 

 basis for an integrated, systemwide assessment of each estuary. 

 The assessment addresses historical trends, present conditions, 

 and probable future trends if current practices are not modified. It 

 is analogous to telling a story about the past, present, and potential 

 future of each estuary. The results are used to substantiate environ- 

 mental problems, evaluate their causes, recommend future 

 remedial and management strategies, and develop long-term 

 monitoring plans. 



Estuary characterization relies primarily on 



existing scientific information, particularly 



historical data. 



Estuary characterization relies primarily on existing scientific infor- 

 mation, particularly historical data. Such information, which can be 

 collected and analyzed relatively efficiently and cost-effectively, 

 provides the most direct way to evaluate trends in estuarine condi- 

 tions. Table 3.1 lists information used for characterization. 



Table 3.1 — Common Kinds of Historical Information Used for Estuary 

 Characterization 

 Pollutant Sources to the Estuary 



• Watershed geomorphology 



• Land use patterns 



• Freshwater input 



• Pollutant loadings: direct discharges, riverine discharges, 

 nonpoint source runoff 



Circulation of Material in the Estuary 



• Weather patterns 



• Tides/currents 



• Salinity 



• Temperature 



• Sediment grain size 

 Distribution of Chemicals in Estuarine Waters and Sediments 



• Organic carbon 



• Nutrients 



• Dissolved oxygen 



• Chemical contaminants 

 Distribution of Biological Organisms in the Estuary 



• Plankton 



• Benthic Invertebrates 



• Fish 



• Aquatic vegetation 



• Endangered species 

 Rates of Biological Processes 



• Primary production 



• Secondary production 



• Respiration 



• Commercial fishery catches 



• Recreational fishery catches 

 Factors Important to Human and Environmental Health 



• Distribution of bacteria and pathogenic organisms 



• Prevalence of disease in fish and shellfish 



• Tissue contaminants 

 Geographic Areas of Special Importance 



• Critical spawning or nursery habitats 



• Recreational areas 



• Beach closures 



• Shellfish harvesting areas 



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