Data Collection
King County uses five RUSS^TM buoys (Remote Underwater Sampling Station buoys) from Apprise Technology to collect water quality data from Lake Washington and Lake Sammamish. The buoys collect water column profiles automatically, 24 hours a day, 365 days a year with only occasional maintenance. Data are transmitted several times every day to our computer system in downtown Seattle, where it is available for viewing from our website.

Data are collected for these lakes using YSI 6600 sondes, which measure water temperature, pH, conductivity, dissolved oxygen and chlorophyll-a. A sonde is a device that measures and transmits physical information.

Each buoy has a 486 computer on board to store the data, run the profiler system, and regularly transmit data to a base station. The buoys are connected to the base station with 56k wireless modems. Across the water, however; the system uses a 900 MHz transceiver between the shore and the buoy as a transparent networking device.

Modeling
The data from the RUSS buoys will help develop models of Lake Washington, Lake Sammamish, the Sammamish River and the Lake Washington Ship Canal.

Lake Washington has been studied extensively revealing a complicated interaction between cyanobacteria, diatoms, and zooplankton. One of the modeling goals is to assist in assessing interaction of juvenile salmonids and zooplankton, a major food source. Noxious algal blooms are another concern and it is desired to be able to simulate the start, duration, and size of a bloom. Initially, the model should be capable of simulating general dynamics between total nitrogen and phosphorous, dissolved oxygen, a single algal group and sediment oxygen demands.

During the summer months, Lake Sammamish thermally stratifies, and because of the relatively shallow depth of the lake, the lower reaches of the lake become anoxic, or low oxygen. During the anoxic periods the sediments release particulate bound phosphorous into the water column. The sediment phosphorous load to water column is a potential eutrophication concern to the lake. The model should adequately simulate sediment dynamics causing the release of bound phosphorous into the water column.

Pollutants of concern include heavy metals, organic compounds, fecal coliforms, and viruses. It is important to be able to simulate the transport, interaction and fate processes of these constituents within the water and bottom sediments. Chemicals tend to absorb most strongly to cohesive soils and suspended particulate organic matter. Sediment deposition is an important process because the lakes are relatively low energy environments tending to collect suspended solids in the sediment beds.

In addition to RUSS^TM data, inputs into the models will include contributions from rivers/streams, non-point surface run-off, groundwater, and precipitation. Atmospheric contributions should also include wind forcing and solar radiation.

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