Below are a selection of links that will tell you everything you ever wanted to know about the St. Lawrence River; from sedimentation and water flow rates to vessel tariffs along the Seaway.

              Parks of the St. Lawrence
              Cornwall and Seaway Valley Tourism
              Brockville, Ontario, Canada 
              Annotated Digital Atlas of Global Water Quality A very good intro to hydrology
              GLREIS  Great Lakes Regioanl Environmental Information System
              GLIMR  Great Lakes Information Management Resource
              Great Lakes St. Lawrence Seaway System
              Great Lakes Vessel Passage
              International St. Lawrence River Board of Control
              Crysler Park Marina
              Prescott, Ontario, Canada
              River Channels, Sediment, and Runoff
              St. Lawrence River sedimentation
              St. Lawrence River - Fish Identification
              St. Lawrence River Charts
              St. Lawrence River Institute
              St. Lawrence River Water Level Bulletin
              The Copeland Cut Reach of the St. Lawrence River
              Tides, Currents and Water Levels in the Great Lakes
              Water - The Transporter