A Yellow Springs Inc. (YSI) multiparameter water quality datasonde (model numbers 6600 EDS, 6600 V2-4 or EXO2) was deployed off the Oregon State University (OSU) pump house dock or OSU Ship Ops dock at the following UTM, Zone 10 North coordinates: 4941737.6 North, 417258.8 East; 4941885.9 North, 417087.8 East, respectively. Temperature, salinity, depth, pH, dissolved oxygen, fluorescence, and turbidity data were collected from 22 January 2009 to 2 April 2025. The YSI sondes were replaced approximately monthly with newly calibrated instruments (calibrated following standard operating procedures) and were deployed at a fixed depth off the bottom. Upon retrieval, the sondes were returned to the laboratory where their performance was checked. A series of custom R scripts were used to post-process all data files. On the “ReadMe” tab is information which includes sonde model used through the deployment period, deployment depth (sonde height off the bottom), and comments related to specific deployment issues.