Assessing spatial variability of nutrients, phytoplankton, and related water quality constituents in the California Sacramento-San Joaquin Delta at the landscape scale: 2024 High-resolution mapping surveys

Broad-area, high-resolution, boat-based water quality mapping surveys of the Sacramento-San Joaquin Delta (Delta) and Suisun Bay were conducted in May, July, and October of 2024. Each survey was comprised of four successive days of high-resolution mapping. The regions covered included the north-south axis of the Delta from the Sacramento River north of Freeport to the Harvey Banks export facility located in the southern Delta, including Old and Middle Rivers; the east-west axis of the Delta from the Sacramento River at Rio Vista to the San Joaquin River at Stockton, including Disappointment Slough and the North and South Forks of the Mokelumne River; and the northern and western Delta from the northern reaches of the Cache Slough Complex to the Grizzly, Honker, and Suisun Bays. On each day, the route of the mapping survey was determined by weather, tides and other logistical considerations. Data were collected at high speed to minimize the extent to which tidal currents obscure nutrient and phytoplankton distributions.