Calculating Effects on Snohomish River Travel Time Using Water Speed, River Discharge, and Tide

Eleanor Geraghty, Josh Searle, Marina Mcleod, and Ardi Kveven, Ocean Research College Academy, Everett Community College, 1205 Craftsman Way Suite 203 Everett, WA 98201

       Salt-wedge estuaries are highly stratified and occur when fast-moving water flows into a body of water with weaker tides. Calculating the travel time of water in an estuary can be useful when predicting pollutant spills, erosion, and depositional effects at the mouth of the river. This study examines the Snohomish River Estuary, which encompasses the Port of Everett Marina and empties into Possession Sound in the Whidbey Basin of the Salish Sea. When the tide flows, water goes north. River travel time calculated by previous Ocean Research College Academy (ORCA) students was approximately 10 hours of delay between a United States Geological Survey (USGS) monitor located 12 miles upriver and water quality data at the river mouth. This previous research shows that there will be less travel time and less water speed during high tides. By cross-correlating river discharge with water speed, a more accurate travel time can be found. Retrieving water speed and direction at the river mouth, current vectors can be developed to help with tide stage comparison. Using the height of water from the riverbed, tidal effect on travel time can be determined through low and high heights correlating to low and high tides. This study investigates July 2020 Acoustic Doppler Current Profiler (ADCP) North/South vectors at the river mouth and correlates it to river discharge upriver. Using Rstudio statistical analysis, this correlation is then compared to ADCP water height to model for tides. It’s predicted that the faster the river discharge and the larger the Southern vectors, then the more drastic decrease in ADCP’s height in the river. Further research would include adding more ADCP data and precipitation to consider seasonal patterns. Since the Snohomish River is fed by runoff, precipitation would create a more accurate travel time model. 


Additional Abstract Information

Presenter: Eleanor Geraghty

Institution: Everett Community College

Type: Poster

Subject: Environmental Science & Sustainability

Status: Approved

Time and Location

Session: Poster 7
Date/Time: Tue 3:30pm-4:30pm
Session Number: 5010