Abstract
One of the principal questions in hydrology is how and when water leaves the critical zone storage as either stream flow or evapotranspiration. We investigated subsurface water storage and storage selection of the Southern Sierra Critical Zone Observatory (California, USA) within the age-ranked storage selection framework, constrained by a novel combination of cosmogenic radioactive and stable isotopes: tritium, sodium-22, sulfur-35, and oxygen-18. We found a significant positive correlation between tritium and stream flow rate and between sulfur-35 and stream flow rate, indicating that the age distribution of stream flow varies with stream flow rate. Storage selection functions that vary with stream flow rate are better able to reproduce tritium concentrations in stream flow than functions that are constant in time. For the Southern Sierra Critical Zone, there is a strong preference to discharge the oldest water in storage during dry conditions but only a weak preference for younger water during wet conditions. The preference of evapotranspiration for younger water, constrained by oxygen-18 in stream water, is essential to parameterize subsurface storage but needs to be confirmed by isotopic or other investigations of evapotranspiration. This is the first study to illustrate how a combination of cosmogenic radioactive isotopes reveals the hydrochronology and water storage dynamics of catchments, constrains the subsurface architecture of the critical zone, and provides insight into landscape evolution.
| Original language | English |
|---|---|
| Pages (from-to) | 1-22 |
| Number of pages | 22 |
| Journal | Water Resources Research |
| Volume | 55 |
| Issue number | 2 |
| Early online date | 29 Jan 2019 |
| DOIs | |
| Publication status | Published - Feb 2019 |
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Keywords
- Hydrochronology
- Oxygen-18
- Sodium-22
- Storage Selection Functions
- Sulfur-35
- Tritium
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Cosmogenic Isotopes Unravel the Hydrochronology and Water Storage Dynamics of the Southern Sierra Critical Zone. / Visser, A.; Thaw, M.; Deinhart, A.; Bibby, R.; Safeeq, M.; Conklin, M.; Esser, B.; Van der Velde, Y.
In: Water Resources Research, Vol. 55, No. 2, 02.2019, p. 1-22.Research output: Contribution to Journal › Article › Academic › peer-review
TY - JOUR
T1 - Cosmogenic Isotopes Unravel the Hydrochronology and Water Storage Dynamics of the Southern Sierra Critical Zone
AU - Visser, A.
AU - Thaw, M.
AU - Deinhart, A.
AU - Bibby, R.
AU - Safeeq, M.
AU - Conklin, M.
AU - Esser, B.
AU - Van der Velde, Y.
PY - 2019/2
Y1 - 2019/2
N2 - One of the principal questions in hydrology is how and when water leaves the critical zone storage as either stream flow or evapotranspiration. We investigated subsurface water storage and storage selection of the Southern Sierra Critical Zone Observatory (California, USA) within the age-ranked storage selection framework, constrained by a novel combination of cosmogenic radioactive and stable isotopes: tritium, sodium-22, sulfur-35, and oxygen-18. We found a significant positive correlation between tritium and stream flow rate and between sulfur-35 and stream flow rate, indicating that the age distribution of stream flow varies with stream flow rate. Storage selection functions that vary with stream flow rate are better able to reproduce tritium concentrations in stream flow than functions that are constant in time. For the Southern Sierra Critical Zone, there is a strong preference to discharge the oldest water in storage during dry conditions but only a weak preference for younger water during wet conditions. The preference of evapotranspiration for younger water, constrained by oxygen-18 in stream water, is essential to parameterize subsurface storage but needs to be confirmed by isotopic or other investigations of evapotranspiration. This is the first study to illustrate how a combination of cosmogenic radioactive isotopes reveals the hydrochronology and water storage dynamics of catchments, constrains the subsurface architecture of the critical zone, and provides insight into landscape evolution.
AB - One of the principal questions in hydrology is how and when water leaves the critical zone storage as either stream flow or evapotranspiration. We investigated subsurface water storage and storage selection of the Southern Sierra Critical Zone Observatory (California, USA) within the age-ranked storage selection framework, constrained by a novel combination of cosmogenic radioactive and stable isotopes: tritium, sodium-22, sulfur-35, and oxygen-18. We found a significant positive correlation between tritium and stream flow rate and between sulfur-35 and stream flow rate, indicating that the age distribution of stream flow varies with stream flow rate. Storage selection functions that vary with stream flow rate are better able to reproduce tritium concentrations in stream flow than functions that are constant in time. For the Southern Sierra Critical Zone, there is a strong preference to discharge the oldest water in storage during dry conditions but only a weak preference for younger water during wet conditions. The preference of evapotranspiration for younger water, constrained by oxygen-18 in stream water, is essential to parameterize subsurface storage but needs to be confirmed by isotopic or other investigations of evapotranspiration. This is the first study to illustrate how a combination of cosmogenic radioactive isotopes reveals the hydrochronology and water storage dynamics of catchments, constrains the subsurface architecture of the critical zone, and provides insight into landscape evolution.
KW - Hydrochronology
KW - Oxygen-18
KW - Sodium-22
KW - Storage Selection Functions
KW - Sulfur-35
KW - Tritium
UR - http://www.scopus.com/inward/record.url?scp=85061937362&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85061937362&partnerID=8YFLogxK
U2 - 10.1029/2018WR023665
DO - 10.1029/2018WR023665
M3 - Article
VL - 55
SP - 1
EP - 22
JO - Water Resources Research
JF - Water Resources Research
SN - 0043-1397
IS - 2
ER -