Table of Contents 
Preface.ii 
Executive Summary.iii 
List of Figures.ix 
List of Tables.xii 
1. Introduction.1 
1.1 Purpose of This Case Study.1 
1.2 Nutrient Criteria Objective.1 
1.3 Designated Uses of Yaquina River and Estuary, Impairments and Assessments.2 
1.4 Oregon Estuarine Water Quality Criteria.4 
1.5 Summary of Yaquina Case Study Approach.4 
2. Description of Study Area.6 
2.1 Physical Characteristics of the Estuary.6 
2.2 Biotic Characteristics.9 
2.3 Land Use and History of Anthropogenic Modifications.13 
2.4 Classification of the Yaquina Estuary.17 
2.5 Conceptual Model for Yaquina Estuary.18 
3. Description of Sources/Sinks of Nutrients.20 
3.1 Background.20 
3.2 Nitrogen Loading to Yaquina Estuary.20 
*3.2.1 Watershed.21 
3.2.2 Ocean Input.22 
3.2.3 Benthic Processes.23 
3.3 Zonation Based Upon Nitrogen Sources.24 
4. Data Sources and Methods.26 
4.1 Yaquina Estuary Data.26 
4.1.1 Recent Data.26 
4.1.2 Additional Data Sources.27 
4.2 Oregon Estuarine Classification Study.30 
4.3 National Coastal Assessment (NCA).30 
4.4 Percentile Approach. 31 
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