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High-speed mapping of water isotopes and residence time in Cache Slough Complex, San Francisco Bay Delta, CA


Publication Date
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O'Donnell, Katy, Downing, B.D. and Bergamaschi, B.A., 2017, High-speed mapping of water isotopes and residence time in Cache Slough Complex, San Francisco Bay Delta, CA: U.S. Geological Survey data release,


Real-time, high frequency (1-second sample interval) GPS location, water quality, and water isotope (δ2H, δ18O) data was collected in the Cache Slough Complex (CSC), located in the northern San Francisco Bay Delta (SFBD). Data was collected on 10/01/2014 for an approximate 4-hour period (10:30 – 14:30 h PST) while underway on the R/V Mary Landsteiner, a 26-foot USGS vessel. Sample water was pumped continuously through a pickup tube, passed through a 178 micron pre-filter, a de-bubbler, and diverted through a 0.2 micron filter and an unfiltered flow path to water quality instrumentation. The real-time data were recorded using a Campbell Scientific CR-6 data logger. Water isotopes (δ2H, δ18O) were logged to a separate CSV file in real-time. [...]


Point of Contact :
Bryan D Downing
Originator :
Katy O'Donnell, Bryan D Downing, Brian Bergamaschi
Metadata Contact :
Katy O'Donnell
publisher :
U.S. Geological Survey
Distributor :
U.S. Geological Survey - Science Base
USGS Mission Area :
Water Resources
SDC Data Owner :
California Water Science Center

Attached Files

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High_Frequency_Mapping_Data_Corrections_Applied.csv 873 Bytes
Water_residence_time_data.xlsx 121.59 KB
High_Frequency_Mapping_Data_Dictionary.xlsx 11.11 KB
Original FGDC Metadata

11.27 KB


The Cache Slough Complex is of high regional importance and of interest to the larger scientific community as it is thought to be a preferred habitat for the indigenous and endangered fish species, the Delta Smelt. Water isotope (δ2H, δ18O) data was used to estimate water residence time in the Cache Slough Complex in an effort to evaluate the impacts of water residence time on key biogeochemical parameters (i.e. nitrate, chlorophyll-a). Water quality data collected by our flow through system provided a dense data set used for characterizing spatial trends. Relationships between water residence time and the water quality data were evaluated.

Additional Information


Type Scheme Key
DOI doi:10.5066/F7H70D0N

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