Water-quality effects on Baker Lake of recent volcanic activity at Mount Baker, Washington

Abstract

Increased volcanic activity on Mount Baker, which began in March 1975, represents the greatest known activity of a Cascade Range volcano since eruptions at Lassen Peak, Calif., during 1914-17. Emissions of dust and increased emanations of steam, other gases, and heat from the Sherman Crater area of the mountain focused attention on the possibility of hazardous events, including lava flows, pyroclastic eruptions, avalanches, and mudflows. However, the greatest undesirable natural results that have been observed after one year of the increased activity are an increase in local atmospheric pollution and a decrease in the quality of some local water resources, including Baker Lake. Baker Lake, a hydropower reservoir behind Upper Baker Dam, supports a valuable fishery resource and also is used for recreation. The lake's feedwater is from Baker River and many smaller streams, some of which, like Boulder Creek, drain parts of Mount Baker. Boulder Creek receives water from Sherman Crater, and its channel is a likely route for avalanches or mudflows that might originate in the crater area. Boulder Creek drains only about 5 percent of the total drainage area of Baker Lake but during 1975 carried sizeable but variable loads of acid and dissolved minerals into the lake. Sulfurous gases and the fumarole dust from Sherman Crater are the main sources for these materials, which are brought into upper Boulder Creek by meltwater from the crater. In September 1973, before the increased volcanic activity, Boulder Creek near the lake had a pH of 6.0-6.6; after the increase the pH was as low as about 3.5. Most nearby streams had pH values near 7. On April 29, in Boulder Creek the dissolved sulfate concentration was 6-29 times greater than in nearby creeks or in Baker River; total iron was 18-53 times greater than in nearby creeks; and other major dissolved constituents were generally 2-7 times greater than in the other streams. The short-term effects on Baker Lake of the acidic, mineral-rich inflow depend mainly on (1) the rate of flow and the character of Boulder Creek water at the time; (2) the relative rate of inflow of the feedwater from other streams; and (3) whether the reservoir is temperature-stratified (summer) or homothermal (winter). A distinct layer of Boulder Creek water was found in the lake in September 1975 extending at least 0.3 miles (0.5 km) downreservoir. The greatest opportunity for water from Boulder Creek to persist as a layer and extend farthest before mixing with the other reservoir water is when Baker Lake is strongly stratified and Boulder Creek flow rate is large in relation to other feedwater. Baker Lake probably could assimilate indefinitely the acid loads measured during 1975, by dilution, chemical neutralization, and buffering of the acid-rich Boulder Creek water. Minor elements found in Boulder Creek water included arsenic, selenium, and mercury; however , none of these would reach the limits recommended by the U.S. Environmental Protection Agency for public water supplies unless their concentrations i...

Investigating mechanisms of edifice deflation, 1981–2007, at Mount Baker volcano, Washington, United States

“…In March 1975, large steam plumes from Sherman Crater were seen from nearby communities. In response to the renewed activity, the U.S. Geological Survey (USGS) began to closely monitor Mount Baker with geodetic, seismic, gravity, petrography, and hydrogeochemical studies [ Bortleson et al , 1977; Malone and Frank , 1976; Radke et al , 1976]. A microgravity survey was conducted between May 1975 and October 1976, which revealed a decrease in gravity (∼330 μ Gal) beneath Sherman Crater [ Malone , 1979].…”

Contribution of organic acids to alkalinity in lakes within the Mount St. Helens blast zone

“…Castle, and Coldwater Lakes ranged from 1,520 to 4,500 peq liter-' and 6.2 and 6.6, respectively (Wissmar et al 1982~~). These alkalinities and pH values were high in comparison to other volcanically impacted lakes (Rose 1977;Bortelson et al 1976Bortelson et al , 1977Kurenkov 1966;Sigurdson 1977;Poe 1980). The eruption was nonmagnetic, had no direct volcanic emission within the lakes, and displayed considerable mineral scavenging by ash (Dethier et al 198 1).…”

“…High DOC concentrations are not typical for lakes in the Cascade Mountains. In April 1980, the total alkalinity (139 peq liter-l), carbonate alkalinity (136 peq liter-l), total CO, (223 PM), and DOC (0.8 mg liter-') concentrations and the pH (7.35) of Spirit Lake were typical of other subalpine lakes in the Cascades (Wissmar et al 1982a, b,c;Reynolds and Johnson 1972;Bortelson et al 1976). These chemical characteristics indicate that the CO2 system (Park 1969) dominated the buffering capacity of these waters.…”

Chemical characteristics for 23 western Washington rivers, 1961-80

“…However, it is not strongly sorbed by organic matter or most secondary minerals, and its concentration in surface waters reflects a balance between precipitation input, chemical weathering, and biological uptake. water from the vicinity of Mount Baker's Sherman Crater (Bortleson et al, 1976) is the likely source of high sulfate concentrations in the Baker and Skagit Rivers. Thermal springs may contribute sulfate to the Nooksack River, but drainage from old mines and weathering of sulfide ores (Moen, 1962) are also potential sources.…”