Mr. Williams et al., Processes regulating the solute concentrations of snowmelt runoff in two subalpine catchments of the Sierra Nevada, California, WATER RES R, 37(7), 2001, pp. 1993-2008
Geochemical processes regulating solute concentrations in snowmelt runoff w
ere investigated for the snowmelt periods of 1992 and 1993 in two subalpine
catchments in Sequoia National Park, California. The catchments, 0.5 and 0
.2 ha, have 10 and 25% soil coverage, respectively; the remaining area is e
xposed granodiorite bedrock. Mineral weathering was the major source of sol
utes in runoff. Calcium export in excess of stoichiometric plagioclase weat
hering was attributed to dry deposition and the weathering of mafic mineral
s and disseminated calcite. Cation exchange was important in the regulation
of K and increased base cation export in response to rain-on-snow events a
nd LiBr tracer. Sulfate fluxes were attributed to snowpack elution and SO4
desorption after the beginning of melt. The selective retention of Li durin
g tracer experiments suggests that acid-neutralizing capacity is linked to
soil stocks along convoluted flow paths and is not necessarily compromised
in areas of sparse soil cover.