High-resolution Water Quality Mapping on California's Bay-Delta

Hydrologist Brian Bergamaschi is seen through the USGS California Water Science Center Biogeochemistry Group's underwater water quality mapping manifold. This maze of tygon tubing allows water to be pumped onto a boat while underway, splits the water into multiple flowpaths, and passes the water to various flow-through water quality instruments through a manifold that controls flow rates to each line.

Although water-quality measurements are typically made throughout the region at fixed stations, measurements are also made underway onboard the vessel at speeds of 20 – 25 knots (23-28 mph). Measurements at this speed allow scientists to cover a large spatial extent over a short period of time; a typical mapping day covers 60-100 river miles. High-resolution mapping provides a novel snapshot of the Bay-Delta, providing a wide variety of information useful for understanding nutrient dynamics, phytoplankton dynamics, and other processes. This approach allows us to simultaneously quantify spatial and temporal differences in water quality that help identify drivers of habitat quality in the Bay-Delta and beyond.