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The Thames Science Plan: Suggested Hydrologic Investigations to Support Nutrient-Related Water-Quality Improvements in the Thames River Basin, Connecticut

U.S. Geological Survey Open-File Report 2005-1208

By Elaine C. Todd Trench

This document is available in Portable Document Format (PDF):  OFR 2005-1208 (11.3 MB)
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The Thames Science Plan is the result of a cooperative project between the U.S. Geological Survey (USGS) and the Connecticut Department of Environmental Protection (CTDEP). The Science Plan outlines water-quality investigations that could provide information necessary for the CTDEP to develop water-quality management and restoration strategies for nutrient-related problems in the Thames River Basin. The purpose of the Science Plan is to identify information that would support CTDEP in developing Total Maximum Daily Load analyses (TMDLs) for nutrients for individual water bodies and stream reaches in the Thames Basin, and eventually for the entire basin, as required under the Federal Clean Water Act.

Development of the Science Plan included a review of the historical database for the Thames River Basin, focusing primarily on water-quality monitoring and interpretive studies conducted by the USGS from 1970 to 2004. Selected additional water-quality information from CTDEP, other state and federal agencies, and academic and private sources has also been reviewed. A complete review and synthesis of all sources of nutrient-related water-quality information for the Thames River Basin is beyond the scope of this Science Plan.

Information on important nutrient-related issues and questions in the Thames River Basin has been obtained from many sources, including reports from the Thames River Water-Quality Symposium, sponsored by the CTDEP on April 30, 2002 (Connecticut Department of Environmental Protection, 2002c). The Thames Technical Workshop, sponsored by the USGS on April 23-25, 2003, provided additional insight into these issues and questions. The Technical Workshop included discussions at several field locations in the Thames Basin, presentations by USGS researchers on freshwater and estuarine nutrient topics, and a moderated discussion among participants from the CTDEP, the USGS, and the U.S. Environmental Protection Agency (USEPA).

The Thames Science Plan is organized into five major sections:

Table of Contents

Purpose, Development, and Organization of the Thames Science Plan


The Importance of Nutrients

Sources of Nutrients in the Thames River Basin

Environmental Setting of the Thames River Basin

Water-Quality Management Issues

Conceptual Model of the Thames River Basin

The Freshwater Ecosystem

Drainage Basins that Receive Point Discharges


Norwich Harbor and the Thames Estuary

Review of the Historical Database for the Thames River Basin

U.S. Geological Survey

Connecticut Department of Environmental Protection

U.S. Army Corps of Engineers

Massachusetts Department of Environmental Protection

Other Sources of Information

Assessment of Information Needs

Ponds and Impoundments

West Thompson Lake

Other Impoundments

Freshwater Streams

Norwich Harbor and the Thames Estuary

Summary of Suggested Investigations to Fulfill Information Needs

Suggested Freshwater Investigations

F1 – Analysis and Interpretation of Information on Nutrient Sources and Water Quality

F2 – Evaluation of Surface-Water-Quality Sampling Design for the Thames River Basin

F3 – Spatial (GIS) Analysis of Thames River Basin Information

F4 – Nutrient Concentrations and Loads in the Quinebaug River Basin

F5 – Quinebaug Phosphorus Trends

F6 – Seasonal Phosphorus Trends in the Quinebaug River

F7 – Annual Nutrient Budget for West Thompson Lake

F8 – Daily and Seasonal Nutrient Loads at West Thompson Lake

F9 – Bioavailable Phosphorus in West Thompson Lake Sediment

F10 –Nutrient Enrichment and Algal Productivity in the Quinebaug River Basin

F11 – Algal Growth Bioassay for West Thompson Lake

F12 –Annual and Seasonal Nutrient Loads from Wastewater-Treatment Facilities

F13 –Nutrient Concentrations and Loads in Pristine, Forested Areas

F14 – Assessment of the Contribution of Nutrients from Ground-Water Inflow

F15 – Quantification of Point and Nonpoint Sources of Nutrients in the Quinebaug River Basin

F16 – Time-of-Travel Studies on the Quinebaug River

F17 – Streamflow Regulation and Effects on West Thompson Lake

F18 – The Effects of Changes in Phosphorus Loading to West Thompson Lake

F19 – Spatial and Temporal Distribution of Nutrient Enrichment and Phytoplankton Algal

F20 – Streamflow Regulation and Water Quality in the Quinebaug River

F21 – Simulation of Phosphorus and Algal Dynamics on the Main Stem of the Quinebaug

F22 – Nutrient Trends in the Thames River Basin

F23 – Preliminary Quantification of Nutrient Sources and Loads for the Shetucket River

F24 – Simulation of Nutrient Loads Based on Watershed Characteristics

F25 – Interstate Thames Watershed Model

Suggested Estuarine Investigations

E1 – Assessment and Interpretation of Available Hydrodynamic and Water-Quality Information for Norwich Harbor and the Thames Estuary

E2 – Monitoring to Define Tidal Hydrodynamics in Norwich Harbor

E3 – Monitoring to Define Water-Quality Variability Over a Range of Climatic and Tidal Conditions in Norwich Harbor

E4 – Sources of Nutrients and Organic Loads to Norwich Harbor

E5 – Phytoplankton Community Composition and Dynamics in Freshwater Inflows and Norwich Harbor

E6 – Assessment of Sediment Oxygen Demand

E7 – Evaluation of Factors Leading to Low Dissolved Oxygen Conditions in Norwich Harbor

Summary of Key Suggested Investigations


Selected References


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