At Fish Hatchery Spring AB, 1 of 3 sites monitored at the Hot Creek Fish Hatchery, several spring vents discharge subaqueously to a pool about 400 ft long and 10-25 ft wide. We monitor discharge, gage height, specific conductance, air temperature, and water temperature at FHAB-WEIR; these data are measured and recorded on a datalogger every 15 minutes. Streamflow and chemistry data are available from NWIS, our national data base.

From 1988 to October 1992, water temperatures were measured with a thermistor placed at the west end of the pool 0.1 ft above the pool floor and above a subaqueous spring vent; this site is called FHAB-UPPER. The flow from the vent declined during January 1992 and, within a few weeks, there was no measurable evidence of discharge. A radical departure of the general water temperature trend occurred during the period January to March 1992 because the flow from the spring vents at the west end of the pool had ceased, and the stagnant water was cooled by winter air temperatures. The temperature site was moved to the east end of the pool near the weir at the outflow point. At this site, the temperature recorded is a flow-weighted average temperature from all the individual vents. This flow-weighted temperature is affected by variations in ambient air and soil temperatures, as well as variations in water temperatures at the spring vents.

We monitor 2 other springs at the Hot Creek Fish Hatchery: Fish Hatchery Spring CD and Fish Hatchery Spring 23. Learn about and compare data for the three monitoring sites here.