Sources of baseflow in larger catchments

using tracers to develop a holistic understanding of runoff generation

Research output: Contribution to journalArticle

68 Citations (Scopus)

Abstract

Despite increasing awareness about the importance of low flows and droughts, spatial and temporal variations in the quantity and quality of baseflow generated in larger catchments are poorly constrained. Here, tracers are used in conjunction with hydrometric analysis to examine the sources of baseflow in the 1849 km(2) catchment of the River Dee in Scotland. Geochemical. tracers showed that the chemical composition of baseflow evolved downstream, but mainly reflected the dominance of sources in montane tributaries in the upper catchment. These findings were corroborated by hydrometric analysis which showed that the upper 54% of the catchment contributed 71% of baseflow in the tower river. Baseflows in smatter (<10 km(2)) headwater sub-catchments exhibited highly variable hydrochemical characteristics which were averaged at larger scales. Analysis of delta O-18 implies that welt-mixed groundwater sources with similar isotopic signatures dominated baseflow generation throughout most of the catchment, probably indicating that groundwater in the lower slopes of montane headwaters provide a major source of baseflow. Periods of baseflow were found to be dynamic; despite the river system being in overall recession, the channel network exhibited contrasting responses to relatively small (<10 mm) isolated rainfall events in different parts of the catchment. Moreover, diurnal variation in flows in sub-catchments with a high proportion of coverage by peat soils is apparent, which may reflect the daily variation of evapotranspiration as a control on baseflow. Although a relatively stable period in the hydrological year, baseflows in larger catchments result from a complex suite of distributed hydrological processes. Further research is needed to understand how baseflows sustain water supplies and aquatic ecosystems, if managers are to be able to protect these catchment services from environmental change. (C) 2008 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)287-302
Number of pages15
JournalJournal of Hydrology
Volume359
Issue number3-4
DOIs
Publication statusPublished - Sep 2008

Keywords

  • baseflows
  • groundwater
  • tracers
  • stable isotopes
  • mesoscale catchments
  • surface-water interactions
  • nested mesoscale catchment
  • different spatial scales
  • stable-isotope tracers
  • residnce times
  • process conceptualization
  • hydrological pathways
  • modeling approach
  • NE Scotland

Cite this

@article{de2a81d53bc0422fbc16cd0732cd87ef,
title = "Sources of baseflow in larger catchments: using tracers to develop a holistic understanding of runoff generation",
abstract = "Despite increasing awareness about the importance of low flows and droughts, spatial and temporal variations in the quantity and quality of baseflow generated in larger catchments are poorly constrained. Here, tracers are used in conjunction with hydrometric analysis to examine the sources of baseflow in the 1849 km(2) catchment of the River Dee in Scotland. Geochemical. tracers showed that the chemical composition of baseflow evolved downstream, but mainly reflected the dominance of sources in montane tributaries in the upper catchment. These findings were corroborated by hydrometric analysis which showed that the upper 54{\%} of the catchment contributed 71{\%} of baseflow in the tower river. Baseflows in smatter (<10 km(2)) headwater sub-catchments exhibited highly variable hydrochemical characteristics which were averaged at larger scales. Analysis of delta O-18 implies that welt-mixed groundwater sources with similar isotopic signatures dominated baseflow generation throughout most of the catchment, probably indicating that groundwater in the lower slopes of montane headwaters provide a major source of baseflow. Periods of baseflow were found to be dynamic; despite the river system being in overall recession, the channel network exhibited contrasting responses to relatively small (<10 mm) isolated rainfall events in different parts of the catchment. Moreover, diurnal variation in flows in sub-catchments with a high proportion of coverage by peat soils is apparent, which may reflect the daily variation of evapotranspiration as a control on baseflow. Although a relatively stable period in the hydrological year, baseflows in larger catchments result from a complex suite of distributed hydrological processes. Further research is needed to understand how baseflows sustain water supplies and aquatic ecosystems, if managers are to be able to protect these catchment services from environmental change. (C) 2008 Elsevier B.V. All rights reserved.",
keywords = "baseflows, groundwater, tracers, stable isotopes, mesoscale catchments, surface-water interactions, nested mesoscale catchment, different spatial scales, stable-isotope tracers, residnce times, process conceptualization, hydrological pathways, modeling approach, NE Scotland",
author = "D. Tetzlaff and C. Soulsby",
year = "2008",
month = "9",
doi = "10.1016/j.jhydrol.2008.07.008",
language = "English",
volume = "359",
pages = "287--302",
journal = "Journal of Hydrology",
issn = "0022-1694",
publisher = "Elsevier Science B. V.",
number = "3-4",

}

TY - JOUR

T1 - Sources of baseflow in larger catchments

T2 - using tracers to develop a holistic understanding of runoff generation

AU - Tetzlaff, D.

AU - Soulsby, C.

PY - 2008/9

Y1 - 2008/9

N2 - Despite increasing awareness about the importance of low flows and droughts, spatial and temporal variations in the quantity and quality of baseflow generated in larger catchments are poorly constrained. Here, tracers are used in conjunction with hydrometric analysis to examine the sources of baseflow in the 1849 km(2) catchment of the River Dee in Scotland. Geochemical. tracers showed that the chemical composition of baseflow evolved downstream, but mainly reflected the dominance of sources in montane tributaries in the upper catchment. These findings were corroborated by hydrometric analysis which showed that the upper 54% of the catchment contributed 71% of baseflow in the tower river. Baseflows in smatter (<10 km(2)) headwater sub-catchments exhibited highly variable hydrochemical characteristics which were averaged at larger scales. Analysis of delta O-18 implies that welt-mixed groundwater sources with similar isotopic signatures dominated baseflow generation throughout most of the catchment, probably indicating that groundwater in the lower slopes of montane headwaters provide a major source of baseflow. Periods of baseflow were found to be dynamic; despite the river system being in overall recession, the channel network exhibited contrasting responses to relatively small (<10 mm) isolated rainfall events in different parts of the catchment. Moreover, diurnal variation in flows in sub-catchments with a high proportion of coverage by peat soils is apparent, which may reflect the daily variation of evapotranspiration as a control on baseflow. Although a relatively stable period in the hydrological year, baseflows in larger catchments result from a complex suite of distributed hydrological processes. Further research is needed to understand how baseflows sustain water supplies and aquatic ecosystems, if managers are to be able to protect these catchment services from environmental change. (C) 2008 Elsevier B.V. All rights reserved.

AB - Despite increasing awareness about the importance of low flows and droughts, spatial and temporal variations in the quantity and quality of baseflow generated in larger catchments are poorly constrained. Here, tracers are used in conjunction with hydrometric analysis to examine the sources of baseflow in the 1849 km(2) catchment of the River Dee in Scotland. Geochemical. tracers showed that the chemical composition of baseflow evolved downstream, but mainly reflected the dominance of sources in montane tributaries in the upper catchment. These findings were corroborated by hydrometric analysis which showed that the upper 54% of the catchment contributed 71% of baseflow in the tower river. Baseflows in smatter (<10 km(2)) headwater sub-catchments exhibited highly variable hydrochemical characteristics which were averaged at larger scales. Analysis of delta O-18 implies that welt-mixed groundwater sources with similar isotopic signatures dominated baseflow generation throughout most of the catchment, probably indicating that groundwater in the lower slopes of montane headwaters provide a major source of baseflow. Periods of baseflow were found to be dynamic; despite the river system being in overall recession, the channel network exhibited contrasting responses to relatively small (<10 mm) isolated rainfall events in different parts of the catchment. Moreover, diurnal variation in flows in sub-catchments with a high proportion of coverage by peat soils is apparent, which may reflect the daily variation of evapotranspiration as a control on baseflow. Although a relatively stable period in the hydrological year, baseflows in larger catchments result from a complex suite of distributed hydrological processes. Further research is needed to understand how baseflows sustain water supplies and aquatic ecosystems, if managers are to be able to protect these catchment services from environmental change. (C) 2008 Elsevier B.V. All rights reserved.

KW - baseflows

KW - groundwater

KW - tracers

KW - stable isotopes

KW - mesoscale catchments

KW - surface-water interactions

KW - nested mesoscale catchment

KW - different spatial scales

KW - stable-isotope tracers

KW - residnce times

KW - process conceptualization

KW - hydrological pathways

KW - modeling approach

KW - NE Scotland

U2 - 10.1016/j.jhydrol.2008.07.008

DO - 10.1016/j.jhydrol.2008.07.008

M3 - Article

VL - 359

SP - 287

EP - 302

JO - Journal of Hydrology

JF - Journal of Hydrology

SN - 0022-1694

IS - 3-4

ER -