Relative influence of upland and lowland headwaters on the isotope hydrology and transit times of larger catchments

Doerthe Tetzlaff, Christopher Soulsby, M. Hrachowitz, M. Speed

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Weekly variation of delta O-18 was measured over 2 years in precipitation and river water in four relatively large catchments in north east Scotland. The River Dee (1712 km(2)) is predominantly upland, with impermeable geology and hydrologically responsive soils. The headwaters of the River North Esk (732 km(2)) are similar, but the lower third of the catchment is underlain by a major sandstone aquifer and is lowland (i.e. < 300 m altitude) in nature. The upper 20% of the River Don catchment (1273 km(2)) is upland, but the remainder is lowland with freely draining soils recharging significant groundwater reservoirs in superficial drifts. The River Ythan catchment (662 km(2)) is entirely lowland and similar to the lower Don. The hydrological responsiveness of the catchments was directly related to their upland area, with the Dee and the North Esk generating the highest specific discharges during high flow events. Conversely, the Don and Ythan had more subdued hydrological regimes, but higher specific discharge under baseflows. Despite broadly similar delta O-18 variation in precipitation inputs, the variability of stream waters was increasingly damped in the order Ythan > Don > North Esk > Dee. Convolution integral models were used to estimate Mean Transit Times (MTTs) for the four catchments from the isotope data. These were reasonably well-constrained at around 2 years for the Dee and 3 years for the North Esk. Estimates for the Don and Ythan were poorly constrained and therefore highly uncertain, but are both likely to exceed 10 years. MTTs in upland catchments in the Scottish Highlands are relatively short (ca. 2 months-4 years) and have been shown to be strongly correlated with soil hydrology, topographic indices and precipitation intensity. However, these relationships change in lowland areas as catchments become less surface water dominated and greater groundwater storage and deeper mixing processes result in much higher MTTs. Nevertheless, a close correlation between soil cover and MTT remains. (C) 2011 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)438-447
Number of pages10
JournalJournal of Hydrology
Volume400
Issue number3-4
Early online date3 Feb 2011
DOIs
Publication statusPublished - 11 Apr 2011

Keywords

  • isotopes
  • tracers
  • large scales
  • lowlands
  • scaling
  • dual tracers
  • residence time
  • landscape characteristics
  • spatial interpolation
  • mesoscale catchment
  • Cairngorm mountains
  • runoff generation
  • ungauged basins
  • stable-isotopes
  • NE Scotland

Cite this

Relative influence of upland and lowland headwaters on the isotope hydrology and transit times of larger catchments. / Tetzlaff, Doerthe; Soulsby, Christopher; Hrachowitz, M.; Speed, M.

In: Journal of Hydrology, Vol. 400, No. 3-4, 11.04.2011, p. 438-447.

Research output: Contribution to journalArticle

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abstract = "Weekly variation of delta O-18 was measured over 2 years in precipitation and river water in four relatively large catchments in north east Scotland. The River Dee (1712 km(2)) is predominantly upland, with impermeable geology and hydrologically responsive soils. The headwaters of the River North Esk (732 km(2)) are similar, but the lower third of the catchment is underlain by a major sandstone aquifer and is lowland (i.e. < 300 m altitude) in nature. The upper 20{\%} of the River Don catchment (1273 km(2)) is upland, but the remainder is lowland with freely draining soils recharging significant groundwater reservoirs in superficial drifts. The River Ythan catchment (662 km(2)) is entirely lowland and similar to the lower Don. The hydrological responsiveness of the catchments was directly related to their upland area, with the Dee and the North Esk generating the highest specific discharges during high flow events. Conversely, the Don and Ythan had more subdued hydrological regimes, but higher specific discharge under baseflows. Despite broadly similar delta O-18 variation in precipitation inputs, the variability of stream waters was increasingly damped in the order Ythan > Don > North Esk > Dee. Convolution integral models were used to estimate Mean Transit Times (MTTs) for the four catchments from the isotope data. These were reasonably well-constrained at around 2 years for the Dee and 3 years for the North Esk. Estimates for the Don and Ythan were poorly constrained and therefore highly uncertain, but are both likely to exceed 10 years. MTTs in upland catchments in the Scottish Highlands are relatively short (ca. 2 months-4 years) and have been shown to be strongly correlated with soil hydrology, topographic indices and precipitation intensity. However, these relationships change in lowland areas as catchments become less surface water dominated and greater groundwater storage and deeper mixing processes result in much higher MTTs. Nevertheless, a close correlation between soil cover and MTT remains. (C) 2011 Elsevier B.V. All rights reserved.",
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T1 - Relative influence of upland and lowland headwaters on the isotope hydrology and transit times of larger catchments

AU - Tetzlaff, Doerthe

AU - Soulsby, Christopher

AU - Hrachowitz, M.

AU - Speed, M.

PY - 2011/4/11

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N2 - Weekly variation of delta O-18 was measured over 2 years in precipitation and river water in four relatively large catchments in north east Scotland. The River Dee (1712 km(2)) is predominantly upland, with impermeable geology and hydrologically responsive soils. The headwaters of the River North Esk (732 km(2)) are similar, but the lower third of the catchment is underlain by a major sandstone aquifer and is lowland (i.e. < 300 m altitude) in nature. The upper 20% of the River Don catchment (1273 km(2)) is upland, but the remainder is lowland with freely draining soils recharging significant groundwater reservoirs in superficial drifts. The River Ythan catchment (662 km(2)) is entirely lowland and similar to the lower Don. The hydrological responsiveness of the catchments was directly related to their upland area, with the Dee and the North Esk generating the highest specific discharges during high flow events. Conversely, the Don and Ythan had more subdued hydrological regimes, but higher specific discharge under baseflows. Despite broadly similar delta O-18 variation in precipitation inputs, the variability of stream waters was increasingly damped in the order Ythan > Don > North Esk > Dee. Convolution integral models were used to estimate Mean Transit Times (MTTs) for the four catchments from the isotope data. These were reasonably well-constrained at around 2 years for the Dee and 3 years for the North Esk. Estimates for the Don and Ythan were poorly constrained and therefore highly uncertain, but are both likely to exceed 10 years. MTTs in upland catchments in the Scottish Highlands are relatively short (ca. 2 months-4 years) and have been shown to be strongly correlated with soil hydrology, topographic indices and precipitation intensity. However, these relationships change in lowland areas as catchments become less surface water dominated and greater groundwater storage and deeper mixing processes result in much higher MTTs. Nevertheless, a close correlation between soil cover and MTT remains. (C) 2011 Elsevier B.V. All rights reserved.

AB - Weekly variation of delta O-18 was measured over 2 years in precipitation and river water in four relatively large catchments in north east Scotland. The River Dee (1712 km(2)) is predominantly upland, with impermeable geology and hydrologically responsive soils. The headwaters of the River North Esk (732 km(2)) are similar, but the lower third of the catchment is underlain by a major sandstone aquifer and is lowland (i.e. < 300 m altitude) in nature. The upper 20% of the River Don catchment (1273 km(2)) is upland, but the remainder is lowland with freely draining soils recharging significant groundwater reservoirs in superficial drifts. The River Ythan catchment (662 km(2)) is entirely lowland and similar to the lower Don. The hydrological responsiveness of the catchments was directly related to their upland area, with the Dee and the North Esk generating the highest specific discharges during high flow events. Conversely, the Don and Ythan had more subdued hydrological regimes, but higher specific discharge under baseflows. Despite broadly similar delta O-18 variation in precipitation inputs, the variability of stream waters was increasingly damped in the order Ythan > Don > North Esk > Dee. Convolution integral models were used to estimate Mean Transit Times (MTTs) for the four catchments from the isotope data. These were reasonably well-constrained at around 2 years for the Dee and 3 years for the North Esk. Estimates for the Don and Ythan were poorly constrained and therefore highly uncertain, but are both likely to exceed 10 years. MTTs in upland catchments in the Scottish Highlands are relatively short (ca. 2 months-4 years) and have been shown to be strongly correlated with soil hydrology, topographic indices and precipitation intensity. However, these relationships change in lowland areas as catchments become less surface water dominated and greater groundwater storage and deeper mixing processes result in much higher MTTs. Nevertheless, a close correlation between soil cover and MTT remains. (C) 2011 Elsevier B.V. All rights reserved.

KW - isotopes

KW - tracers

KW - large scales

KW - lowlands

KW - scaling

KW - dual tracers

KW - residence time

KW - landscape characteristics

KW - spatial interpolation

KW - mesoscale catchment

KW - Cairngorm mountains

KW - runoff generation

KW - ungauged basins

KW - stable-isotopes

KW - NE Scotland

U2 - 10.1016/j.jhydrol.2011.01.053

DO - 10.1016/j.jhydrol.2011.01.053

M3 - Article

VL - 400

SP - 438

EP - 447

JO - Journal of Hydrology

JF - Journal of Hydrology

SN - 0022-1694

IS - 3-4

ER -