Identification

Title

Unravelling groundwater contributions to evapotranspiration and constraining water fluxes in a high-elevation catchment

Abstract

Despite the importance of headwater catchments for the water supply of the western United States, these regions are often poorly understood, particularly with respect to quantitative understanding of evapotranspiration (ET) fluxes. Heterogeneity of land cover, physiography, and atmospheric patterns in these high-elevation regions lead to difficulty in developing spatially-distributed characterization of ET. As the largest terrestrial water flux behind precipitation, ET represents a significant fraction of the water budget for any watershed. Likewise, groundwater is the largest available freshwater store and has been shown to play a large role in the water balance, even in headwater systems. Using an eddy covariance tower in the East River Catchment, a Colorado River headwaters basin, we estimated water and energy fluxes in high-elevation, complex systems to better constrain ET estimates and calculate overall water and energy budgets, including losses from groundwater. We used the eddy covariance method to estimate ET from years 2017 through 2019 at a saturated, riparian end-member site. Owing to complexities in near surface atmospheric structure such as stable boundary layers over snowpack and shallow terrain driven flow from surrounding landscape features, energy flux and ET estimates were limited to the warm season when energy closure residuals from the eddy-covariance system were reliably less than 30%, a threshold commonly used in eddy covariance energy flux estimation. The resulting ET estimations are useful for constraining water budget estimates at this energy-limited site, which uses groundwater for up to 84% of ET in the summer months. We also compared East River ET magnitudes and seasonality to two other flux towers (Niwot Ridge, CO and Valles Caldera, NM), located in the Rocky Mountains. These data are useful for constraining ET estimates in similar end-member locations across the East River Catchment. Our results show that groundwater-fed ET is a significant component of the water balance and groundwater may supply riparian ET even during low-snow years.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7pk0kp6

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2022-01-04T00:00:00Z

Frequency of update

Quality and validity

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Conformity

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name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact