Lowell F. W. Duell | USGS Science

USGS2007

Design and implementation of evapotranspiration measuring equipment for Owens Valley, California

As part of a plant survivability and ground water study in Owens Valley, California, semipermanent installations are used to measure continuous range‐land evapotranspiration in the valley's phreatophyte community. A proposed mobile installation also has been designed. The semipermanent micrometeoro‐logical station collects continuous data for solution of the Bowen ratio/energy budget equation and the Penman combination equation. Three sites were chosen for this type of installation to provide a representative sampling of Owens Valley. The proposed mobile aerodynamic installation should be capable of calculating evapotranspiration by the eddy correlation method. This instrumentation will be used throughout the valley for short periods of time (up to five days). Many problems with equipment operation, calibration and design have been identified and resolved by means of improved calibration techniques, systematic error‐removal techniques, reduced cycle times, modified equipment design and proper observer training. The collected evapotranspiration data will be instrumental in developing a one‐dimensional evapotranspiration flux algorithm for a model of valleywide ground water flow.

California↗

USGS1991

Ground-water data for San Nicolas Island, California, 1989-90

In an effort to gain geohydrologic knowledge and to increase the availability of ground water to the U.S. Navy on San Nicolas Island, nine test wells were drilled by the U.S. Geological Survey in 1989 and one production well was drilled by the U.S. Navy in 1990. One of the nine test wells was dry, five produced less than 10 gallons of water per day, two produced between 20 and 30 gallons per day, and one produced 400 gallons per day. The production well produced about 900 gallons per day. Water samples were collected from eight wells during 1989-90 and analyzed for concentrations of major dissolved inorganic ions and nutrients. Five of the sampled wells were constructed in 1989, one was constructed in 1990, and two were constructed prior to 1989. Data from the study are presented in tables and graphs. Included are geophysical, lithologic, and well-construction data and results obtained from well-pumping tests and from the chemical analysis of water from selected wells.

California↗