ANALYSIS OF GEYSER BEHAVIOR OF THE KLICKITAT MINERAL SPRINGS, WASHINGTON

Several springs of warm (13-27 °C), high specific conductivity (600-1,800 µS/cm), and carbon dioxide (CO₂) enriched groundwater emerge into southern Washington’s Klickitat River where faulting in the Columbia River Basalt Group provides a pathway for rising groundwater in underlying Oligocene-Miocene volcaniclastics. In the mid-1900s, the Gas-Ice Corporation developed these springs into (now-abandoned) wells used to collect CO₂ for dry ice production. At its peak, the corporation produced 18 tons of dry ice per day using CO₂ from the Klickitat spring wells. While the production facilities are now gone, many open wellheads remain and act as geysers. Past and current water chemistry samples from these wells clearly identify Ca-Mg-HCO₃-type groundwater, strongly enriched in bicarbonate (>400 mg/L).

This study is a first look at time-series behavior from one of the Klickitat well geysers. We used an In-Situ AquaTroll 600 to measure temperature (T), pH, specific conductivity (SpC), dissolved oxygen (DO), oxygen-reduction potential (ORP), and depth (D) every 5 minutes for a six-week window in July and August of 2023. We used correlograms and fast-Fourier transforms of the data produced in MATLAB to examine underlying patterns.

The resulting data reveal cyclic geyser activity, expressed as a rapid drop in SpC and D when rising bubbles displace water surrounding the sonde and in the overlying water column, respectively. The well alternates between windows of geyser and non-geyser behavior on a regular schedule spanning 23-25 hours, including 5-7 hours of quiescence followed by 16-17 hours of activity. During each window of geyser activity, there are 5-6 periods of eruption and quiescence, each lasting approximately 2.75 hours. Preceding each geyser period by 2-3 hours, D increases by 3 feet with a slight increase in pH, DO, and ORP. Values of T increase from 24.8 °C to 26 °C 10-15 minutes after the beginning of each eruption and cool back down during the longer non-geyser window. Values of pH and ORP briefly drop below baseline for 5-10 minutes at the onset of each eruption period and climb above baseline as each eruption wains. These observations provide useful insights into the source reservoir for the thermal, CO₂-enriched groundwater and suggest that tidal stress may contribute to geyser processes.