In:
Hydrology and Earth System Sciences, Copernicus GmbH, Vol. 22, No. 8 ( 2018-08-14), p. 4295-4310
Abstract:
Abstract. During spring, daily stream flow and groundwater dynamics in forested subalpine catchments
are to a large extent controlled by hydrological processes that
respond to the day–night energy cycle. Diurnal snowmelt and transpiration
events combine to induce pressure variations in the soil water storage that
are propagated to the stream. In headwater catchments these pressure
variations can account for a significant amount of the total pressure in the
system and control the magnitude, duration, and timing of stream inflow
pulses at daily scales, especially in low-flow systems. Changes in the
radiative balance at the top of the snowpack can alter the diurnal hydrologic
dynamics of the hillslope–stream system, with potential ecological and
management consequences. We present a detailed hourly dataset of atmospheric, hillslope, and
streamflow measurements collected during one melt season from a semi-alpine
headwater catchment in western Montana, US. We use this dataset to
investigate the timing, pattern, and linkages among snowmelt-dominated
hydrologic processes and assess the role of the snowpack, transpiration, and
hillslopes in mediating daily movements of water from the top of the snowpack
to local stream systems. We found that the amount of snowpack cold content
accumulated during the night, which must be overcome every morning before
snowmelt resumes, delayed water recharge inputs by up to 3 h early in the
melt season. These delays were further exacerbated by multi-day storms (cold
fronts), which resulted in significant depletions in the soil and stream
storages. We also found that both diurnal snowmelt and transpiration signals
are present in the diurnal soil and stream storage fluctuations, although the
individual contributions of these processes are difficult to discern. Our
analysis showed that the hydrologic response of the snow–hillslope–stream
system is highly sensitive to atmospheric drivers at hourly scales and that
variations in atmospheric energy inputs or other stresses are quickly
transmitted and alter the intensity, duration, and timing of snowmelt pulses
and soil water extractions by vegetation, which ultimately drive variations
in soil and stream water pressures.
Type of Medium:
Online Resource
ISSN:
1607-7938
DOI:
10.5194/hess-22-4295-2018
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2018
detail.hit.zdb_id:
2100610-6
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