Time-variation of hydrothermal discharge at selected sites in the western United States: implications for monitoring
Introduction
In this paper we review what is known about the natural time-variation in mass and heat discharge from selected hydrothermal systems in the western United States. Our focus on the United States in part reflects the geographic emphasis of the U.S. Geological Survey (USGS), but also the fact that much of the reliable data on time-variation of hydrothermal discharge derives from studies done in the western United States during the latter part of the 20th century. These data were collected for various purposes, including basic understanding of water–rock interaction (e.g. Fournier et al., 1975, Ingebritsen et al., 1994), environmental-baseline monitoring (e.g. Norton et al., 1989, Sorey and Colvard, 1994, Sorey and Colvard, 1997, Sorey et al., 1994, Friedman and Norton, 2000), volcano monitoring (e.g. Farrar et al., 1985, Sorey et al., 1998), and water-quality monitoring as part of the USGS National Assessment of Water Quality. Much of the data collection was driven by mandates to collect environmental-baseline data in anticipation of geothermal development. The data provide a quantitative basis for assessing the seasonal to multi-decadal variability of some types of hot-spring discharge. The findings are relevant to: (1) the design of environmental-baseline monitoring programs intended to protect geothermal features; (2) the value of hydrothermal-discharge monitoring as a component of comprehensive volcano-monitoring programs; and (3) heat-budget studies of areas with significant advective heat loss (e.g. Ingebritsen et al., 1989, 1994; Manga, 1998, James et al., 1999), which often assume that heat discharge from spring systems is constant.
Two electronic spreadsheets are an integral part of this report. These are accessible through a link labeled ‘hydrothermal discharge in the western United States’ under http://water.usgs.gov/nrp/proj.bib/ingebritsen.html. They include full details of all measurements from high-chloride spring (highclspringdat.PDF) and fumarolic areas (acidsulfatedat.PDF), metadata with complete descriptions of the sites and methods, and basic time-series plots for each site (Skoustad et al., 1979, Farrar et al., 1989, Fishman and Friedman, 1989, Friedman et al., 1993, Howle and Farrar, 1996). We cite these spreadsheets in support of some particular points in the report; interested readers can use the spreadsheets to do their own complementary analyses. An index at the beginning of each spreadsheet facilitates cross-referencing with text, figures, and tables.
The scope of our discussion is mainly limited to the western United States and further limited to natural (non-anthropogenic) variations in mass and heat discharge. Geothermal development commonly leads to rapid and profound changes in thermal features — typically large and semi-permanent reductions in liquid discharge (Henley and Stewart, 1983, Turner, 1985, White, 1992, Glover and Hunt, 1996, Glover et al., 1996) and more temporary increases in steam discharge (Allis, 1981, Henley and Stewart, 1983, Ingebritsen and Sorey, 1985). Human impact on geothermal features in New Zealand and the western United States has recently been reviewed by Glover and Hunt, 1998, Sorey, 2000, respectively.
Three types of thermal features are commonly distinguished: high-chloride springs; geothermal fumaroles and associated acid-sulfate springs; and volcanic fumaroles (Fig. 1).
High-chloride springs emerge from liquid-dominated hydrothermal systems, generally have a near-neutral pH, and are commonly high in silica as well as chloride. Well-known examples in the western United States include the springs of Upper and Lower Geyser Basins, Yellowstone. Such features often occur in valleys near streams that eventually capture most of the thermal fluid, so their total discharge can often be gauged by measuring the solute flux in these adjacent streams. Discharge time-series from high-chloride spring systems in the western United States are relatively detailed and abundant.
Geothermal fumaroles (steam vents) and associated acid-sulfate springs are derived from steam up-flow generated by boiling of meteoric waters. Evolution of CO2 and H2S with the steam, and subsequent partial condensation and dissolution in shallow groundwater, leads to acid-sulfate springs with low pH, typically high dissolved CO2, and variable sulfur (White et al., 1971). Well-known examples in the western United States include the thermal features of Lassen Volcanic National Park and Yellowstone's Mud Volcanoes. The total fumarolic and ‘steam-heated’ (acid-sulfate-spring) discharge is best measured by using total heat discharge as a proxy. Measurement of the multiple modes of heat discharge is time-consuming and difficult, and time series of fumarole and steam-heated discharge are sparse and rare, both in the United States and worldwide.
Volcanic fumaroles and associated springs occur where magmatic fluids reach, or nearly reach, the land surface. Whereas geothermal fumaroles are limited to <∼160°C — the temperature obtained by adiabatic decompression of saturated steam of maximum enthalpy — volcanic fumaroles often reach temperatures of hundreds of degrees Celsius. The pH and composition of any associated springs depends upon the degree of interaction between the magmatic steam, meteoric water, and wallrock (Hedenquist, 1995, Reed, 1997). Along the western rim of the Pacific Ocean, high-temperature volcanic fumaroles are relatively common, and associated springs are often high in both chloride and sulfur. In the United States, volcanic fumaroles occur along the Aleutian arc, on the Alaska Peninsula, and in the Cascade Range, but they are relatively rare and weak, and associated springs are usually low in chloride. Many volcanic fumaroles are relatively inaccessible and their surroundings potentially dangerous. There are few reliable measurements of total mass or heat flux except in special circumstances where magmatic steam condenses into crater lakes, which also act as calorimeters (e.g. Brantley et al., 1993, Varekamp and Rowe, 2000).
The same monitoring methods apply to both geothermal and volcanic fumaroles. Therefore, for purposes of the discussion that follows, we will consider only two broad categories of hydrothermal features: high-chloride springs (highclspringdat.PDF) and fumaroles (acidsulfatedat.PDF). We will touch on the distinction between geothermal and volcanic fumaroles again in Section 4 that concludes this paper.
The history of some developed hot springs in Europe indicates no dramatic changes in discharge, temperature, or chemical composition over millennia of casual human observation. Waring (1965), who published a global inventory of thermal springs, wrote that “(m)any hot springs have been described as remarkably uniform in temperature, flow, and mineral content,” and noted that “(a)s most observations of the temperature and flow of thermal springs have been made at intervals of many years, no trends in their changes have been established.”
In his monumental effort, Waring (1965) inventoried 1185 thermal-spring localities in the United States, mainly in California, Idaho, Nevada, Oregon, and Wyoming. Though he listed flow rates for most of the springs, a general lack of methodological detail leads us to regard the flow-rate data as non-quantitative. We will use Breitenbush Hot Springs, Oregon, as an example: for Breitenbush, Waring (1965) listed a flow rate equivalent to 60 l/s, and cited Langville et al. (1903) as a reference. This value, along with many others from Waring (1965), was repeated in USGS Circulars that assessed the geothermal resources of the United States in 1975 and 1978 (White and Williams, 1975, Muffler, 1978). However, Langville et al. (1903) listed no flow-rate data for Breitenbush; Waring (1965) provided no independent support for the 60 l/s value; and solute-inventory measurements made in the Breitenbush River in 1984–99 documented a flow rate of 12.5±1.5 l/s (n=6). The constancy of the data in the 1980s and 1990s, combined with the lack of supporting detail in Waring (1965), prompts us to discount the much higher reported value.
Most flow rates reported in the early literature were likely based on non-quantitative visual observation, sometimes combined with direct measurement of individual orifices. We place much more confidence in flow rates determined more recently by solute-inventory or heat-flux measurements. A few of the measurements reported by Day and Allen, 1925, Allen and Day, 1935 in the early 20th century are sufficiently detailed to provide an earlier point of comparison.
Section snippets
Methods of measurement
In most cases high-chloride spring discharge is best measured by the solute- (chloride) inventory method pioneered in New Zealand (Ellis and Wilson, 1955) and fumarolic discharge is best measured by the heat-flux methods pioneered in New Zealand (Dawson, 1964, Dawson and Dickinson, 1970) and Japan (Yuhara, 1970, Sekioka and Yuhara, 1974), and later refined for use in the western US (Sorey and Colvard, 1994). Because many hydrothermal-discharge areas include numerous vents, some of which may be
High-chloride springs
We compiled 3481 chloride-flux measurements of high-chloride hydrothermal discharge from a variety of publications and from USGS files. Some aspects of these data are summarized in Table 1, and the entire data set is contained in (highclspringdat.PDF). We chose to consider 18 sites in the western United States for which there are at least six measurements over a multiyear period (Fig. 3). Most of these (11), and most of the individual measurements (>3200), are from the Yellowstone region; the
Discussion and summary
From numerous publications and the USGS archives we have been able to compile multi-year time-series consisting of 3481 measurements of high-Cl hydrothermal discharge at 18 sites (highclspringdat.PDF) and 112 measurements of heat discharge at 6 sites in fumarolic areas (acidsulfatedat.PDF). These data are from selected systems in the western United States where the hydrothermal phenomena are believed to be as yet unaffected by human activity. Consideration of these data as a whole suggests
Acknowledgements
Thoughtful reviews by our USGS colleagues Julie Donnelly-Nolan and Jake Lowenstern and JVGR referees Jennifer Lewicki and Lisa Shevenell helped us to improve earlier versions of this manuscript.
References (83)
Geochemistry of fluids associated with the 1995–1996 eruption of Mt. Ruapehu, New Zealand: signatures and processes in the magmatic-hydrothermal system
Journal of Volcanology and Geothermal Research
(2000)- et al.
Heat flow studies in thermal areas of North Island: United Nations Symposium on the Development and Use of Geothermal Resources, Pisa, Italy
Geothermics
(1970) - et al.
Chemical changes in spring waters at Tacana volcano, Mexico: a possible precursor of the May 1986 seismic crisis and phreatic explosion
Journal of Volcanology and Geothermal Research
(1989) - et al.
Chemical and isotopic changes in the hydrology of the Tauhara geothermal field due to exploitation at Wairakei
Journal of Volcanology and Geothermal Research
(1983) - et al.
Chemical evolution and volcanic activity of the active crater lake of Poas volcano, Costa Rica, 1993–1997
Journal of Volcanology and Geothermal Research
(2000) - et al.
Chloride flux out of Yellowstone National Park
Journal of Volcanology and Geothermal Research
(1985) - et al.
Fluid-volcano interaction in an active stratovolcano: The crater lake system of Poas volcano, Costa Rica
Journal of Volcanology and Geothermal Research
(1992) - et al.
Evolution of hydrothermal waters at Mount St. Helens, Washington, USA
Journal of Volcanology and Geothermal Research
(1995) - et al.
Temporal geochemical variations in volatile emissions from Mount St. Helens, USA
Journal of Volcanology and Geothermal Research
(2000) - et al.
Hydrologic Investigations in the Mammoth corridor, Yellowstone National Park and vicinity, USA
Geothermics
(1997)
Direct observation of the evolution of a seafloor ‘black smoker’ from vapor to brine
Earth and Planetary Science Letters
Heat transfer measurement in a geothermal area
Tectonophysics
Volatile fluxes integrated over four decades at Grimsvotn volcano, Iceland
Journal of Geophysical Research
Changes in heat flow associated with exploitation of Wairakei geothermal field, New Zealand
New Zealand Journal of Geology and Geophysics
Kelut volcano monitoring: hazards, mitigation and changes in water chemistry prior to the 1990 eruption
Geochemical Journal
Crater lakes reveal volcanic heat and volatile fluxes
GSA Today
Energy budget analysis for Poas crater lake: implications for predicting volcanic activity
Nature
Evolution of a vent-hosted hydrothermal system beneath Ruapehu Crater Lake
New Zealand. Bulletin of Volcanology
Continuous monitoring of high-temperature fumaroles on an active lava dome, Volcan Colima, Mexico: Evidence of mass flow variation in response to atmospheric forcing
Journal of Geophysical Research
The nature and assessment of heat flow from hydrothermal areas
New Zealand Journal of Geology and Geophysics
The heat from the Wairakei–Taupo thermal region calculated from the chloride output
New Zealand Journal of Science and Technology
Geochemistry and dynamics of the Yellowstone National Park hydrothermal system
Annual Reviews of Earth and Planetary Science
Monitoring of thermal activity in southwestern Yellowstone National Park, 1980–1993
U.S. Geological Survey Bulletin
The chemistry of fumarolic vapor and thermal-spring discharges from the Nevado del Ruiz hydrothermal system, Columbia
Journal of Volcanology and Geothermal Research
The ascent of magmatic fluid: Discharge vs. mineralization
Cited by (69)
Heat flux in volcanic and geothermal areas: Methods, principles, applications and future directions
2023, Gondwana ResearchCitation Excerpt :However, this method in the field requires a) that the chloride concentration in the spring is high, generally more than 100 ppm; b) that multiple hot springs discharge into an apparently regular channel for flow measurement; c) that there is no other hot fluid in the channel that the hot spring discharges into; and d) that the flow of the spring is large enough to be measured. This method has many limitations; if the flow rate of the spring is low in arid areas (Ingebritsen et al., 2001) or there is no suitable channel for hot spring discharge in the field, then this method is not suitable (Haselwimmer and Prakash, 2013). Applications: This method has been used in the evaluation of heat loss, including for the Long Valley geothermal area (Ingebritsen et al., 2001), Cascade Mountain geothermal area (Ingebritsen and Mariner, 2010), and Yellowstone National Park geothermal area (Friedman and Norton, 2007).
Fault-controlled springs: A review
2022, Earth-Science ReviewsDynamics of natural discharge of the hydrothermal system and geyser eruption regime in the Valley of Geysers, Kamchatka
2022, Applied GeochemistryCitation Excerpt :The estimation of the deep component of thermal Qd in the YNP was pioneered by R. Fournier (1989). A great description of the Cl inventory was also given by Ingebritsen et al., (2001). In this paper, to estimate the total mass discharge of the deep component of thermal water (Qd, kg/s), the mass rate of discharge of the river (Qr, kg/s), and the Cl mass fraction (kg/kg) carried by the river waters (Cr) were utilized (in SI units).
Heat flux measurements and thermal potential of the Garze geothermal area in the eastern Himalayan Syntaxis
2021, Journal of Volcanology and Geothermal ResearchThe Alpehue geyser field, Sollipulli Volcano, Chile
2020, Journal of Volcanology and Geothermal Research