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Most King County offices will be closed on Thursday and Friday, Nov. 22-23, 2018, for the Thanksgiving holiday.  
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The map on the buoy home page shows the locations of currently active and inactive profiling buoys and surface meteorological monitoring locations on Lake Washington and Lake Sammamish. These buoys are part of the Major Lakes Monitoring Program. To view the latest surface data hover over the active site map pins. You can also view the latest profile plots by clicking the Latest Profiles link on the left, the latest 24-hour meteorological data by clicking on the Latest Weather link, or view or download the latest data by selecting the View or Download Data link. To view historical profiles or annual contour plots or view or download historical data, select the appropriate link on the left.

The profiling buoys collect data on water temperature, dissolved oxygen, pH, specific conductance, chlorophyll fluorescence, and turbidity from near the bottom to within 1 meter of the surface at 1-meter depth intervals. The number of profiles per day depends on the solar panel output – generally between 3 profiles per day in winter to 6 profiles per day in summer. The inactive buoys conducted profile sampling 4 times per day throughout the year. The active sites also support meteorological stations, which currently report hourly average air temperature, relative humidity, wind speed, wind direction, and total solar radiation. Further details regarding the equipment and specifications of the active buoy stations can be found by selecting the Buoy Specifications link. Definitions of common lake water quality terms found on this site can be found on the Lakes Glossary page.