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Water Quality Monitoring
Barker Slough Water Quality QuB

The monitoring system (or QuB pronounced "cube") was designed for the Solano County Water Agency (SCWA) to serve as a real-time monitoring station, to alert downstream Water Treatment Plants (WTPs) of real-time changes in their raw source water.

The Barker Slough system is significantly impacted by local wintertime runoff events. In particular, during and after runoff events for weeks to months at a time, the source water contains high levels of dissolved organic carbon (DOC) that can lead to high levels of harmful disinfection by products, if improperly treated. The purpose of the Barker Slough Water Quality QuB is to measure real-time levels of DOC in Barker Slough, but with minimal maintenance and staff time required. Since direct measurement of DOC by laboratory instruments was deemed impractical, two surrogate parameters were used: UVA-254 and fDOM (Fluorescent Dissolved Organic Matter). To accurately measure UVA-254 and fDOM, water is pre-filtered using a set of 3 in-line cartridge filters (10 µm, 1 µm, 0.45 µm). Turbidity is also measured as part of the cube.

To date, the station has been running for over 2-years. The surrogate DOC parameters, and in particular fDOM, have proven to be very accurate and helpful in tracking real-time DOC levels and trends in Barker Slough. Furthermore, downstream WTP operators have been able to make more informed decisions on blending, switching of source waters, and allowing for a more proactive vs. reactive approach.

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Content provided by:Alexander A. Rabidoux, P.E.
Water Resources Engineer
Solano County Water Agency