Investigating DOC export dynamics using high-frequency ...
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Investigating DOC export dynamics using high-frequency instream concentration measurements M.R. Oosterwoud 1 , T. Keller 1 , S. Frei 2 , K.H. Knorr 3 , E. Matzner 2 , J.H. Park 4 and J.H.Fleckenstein 1 We explored: What can high resolution in-situ UV-Vis measurements tell us about dissolved organic carbon (DOC) export dynamics from catchments under different hydrological and climatic conditions Background Methods Department of Hydrogeology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, e-mail: [email protected], T: +49 (0)341 235 1069 • In-situ UV-Vis spectrometers allow to obtain certain water quality parameters (e.g. DOC) at high frequency in hydrologically dynamic catchments • DOC-Q loops can be used to identify source areas and flow paths and give insight into mobilization mechanisms • Catchment size, structure (e.g. topography, morphology) and climate strongly influence DOC-Q loops loops are distinct for a catchment type Flexible UV-Vis probe setup, measuring light absorbance from 220-735 nm (2.5 nm increments). Values for DOC are obtained using a built-in algorithm and local calibration. Stream discharge (Q) is obtained from hydraulic weirs and developed stage-discharge rating curves (Q vs. h) Increasing transport of DOC from soils to streams and subsequent higher DOC loads in surface waters cause problems for drinking water purification from surface waters. Growing interest in high resolution time series of water quality data. Being able to monitor DOC using in- situ high frequency measurements is considered fundamental to better understand DOC behaviour under different hydrological and climatic conditions. Contact Time series of Q, EC and DOC from headwaters of Rappbode catchment 5 10 15 20 25 30 35 0 0.1 0.2 0.3 0.4 0.5 0.6 Q [m 3 /s] DOC [mg/l] event 1 event 2 event 3 DOC-Q loops for 3 summer events in 2010 Flexible UV-Vis setup; ensures flexible application under field conditions DOC-Q loops for 3 events in late spring 2013 counter-clockwise: groundwater dominated, delayed response riparian zones clockwise: surface runoff dominated, fast response top soil flushing during event Field sites t 1 t 2 clay layer peat t 1 t 2 clay layer peat t 3 t 2 clay layer peat granitic bedrock regolith topsoil / litter granitic bedrock regolith topsoil / litter granitic bedrock regolith topsoil / litter DOC concentration Q stream DOC concentration Q stream fresh peat (high DOC) decomposed peat (low DOC) flow routes (width = magnitude) rising hydrograph peak flow falling hydrograph C-Q relationship Lehstenbach Haean Time series of Q and DOC from the outlet of the Lehstenbach catchment Lehstenbach catchment (4.2 km 2 ) Rappbode catchment (44 km 2 ) Q [m 3 /s] DOC-Q relationships for 3 events of different intensity (from Jeong et al. 2012) Q [m 3 /s] DOC [mg/l] DOC-Q loops pooled for all 42 monitored events We found: Continuous DOC and Q data from three catchments of different size: 1) 1 st -order catchment (0.4 km 2 ) in the Haean watershed, South Korea, forested, monsoonal climate with intense runoff events 2) Lehstenbach catchment (4.2 km 2 ), South-East Germany (Fichtelgebirge), forested with peat-forming riparian wetlands 3) Rappbode catchment (44 km 2 ), Central Germany (Harz), mixed landuse, mainly forested Results References: Jeong J.J., Bartsch S., Fleckenstein J.H., Matzner E., Tenhunen J. Lee S.D., Park S.K., Park J.H. (2012) Differential storm responses of dissolved and particulate organic carbon in a mountainous headwater stream investigated by high-frequency in-situ optical measurements, Journal of Geophysical Research – Biogeosciences, 117, doi 10.1029/2012JG001999 Strohmeier S., Reichert M., Frei S., Knorr K.-H., Fleckenstein J.H., Peiffer S., Matzner E. (2013) Concentrations and fluxes of dissolved organic carbon in runoff from a forested catchment: insights from high frequency measurements, Biogeosciences,10:905-916 conceptual models 1) Department of Hydrogeology, Helmholtz Center for Environmental Research - UFZ, Leipzig, 2) University of Bayreuth, 3) University of Münster, 4) EWA Womans University, Seoul, South Korea EGU2014-15385
Transcript of Investigating DOC export dynamics using high-frequency ...
Investigating DOC export dynamics using high-frequency instream concentration measurements M.R. Oosterwoud1, T. Keller1, S. Frei2, K.H. Knorr3, E. Matzner2, J.H. Park4 and J.H.Fleckenstein1
We explored: What can high resolution in-situ UV-Vis measurements tell
us about dissolved organic carbon (DOC) export dynamics from catchments under different hydrological and climatic conditions
Background
Methods
Department of Hydrogeology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, e-mail: [email protected], T: +49 (0)341 235 1069
• In-situ UV-Vis spectrometers allow to obtain certain water quality parameters (e.g. DOC) at high frequency in hydrologically dynamic catchments
• DOC-Q loops can be used to identify source areas and flow paths and give insight into mobilization mechanisms
• Catchment size, structure (e.g. topography, morphology) and climate strongly influence DOC-Q loops loops are distinct for a catchment type
Flexible UV-Vis probe setup, measuring light absorbance from 220-735 nm (2.5 nm increments). Values for DOC are obtained using a built-in algorithm and local calibration. Stream discharge (Q) is obtained from hydraulic weirs and developed stage-discharge rating curves (Q vs. h)
Increasing transport of DOC from soils to streams and subsequent higher DOC loads in surface waters cause problems for drinking water purification from surface waters. Growing interest in high resolution time series of water quality data. Being able to monitor DOC using in-situ high frequency measurements is considered fundamental to better understand DOC behaviour under different hydrological and climatic conditions.
Contact Time series of Q, EC and DOC from headwaters of Rappbode catchment
5
10
15
20
25
30
35
0 0.1 0.2 0.3 0.4 0.5 0.6
Q [m3/s]
DO
C [m
g/l]
event 1event 2event 3
DOC-Q loops for 3 summer events in 2010
Flexible UV-Vis setup; ensures flexible application under field conditions
DOC-Q loops for 3 events in late spring 2013
counter-clockwise: groundwater dominated, delayed response riparian zones clockwise: surface runoff dominated, fast response top soil flushing during event
Field sites
t1t2
clay layer
peat
t1t2
clay layer
peat
t3t2
clay layer
peat
granitic bedrockregolith
topsoil / litter
granitic bedrockregolith
topsoil / litter
granitic bedrockregolith
topsoil / litter
DO
C c
once
ntra
tion
Q stream
DO
C c
once
ntra
tion
Q stream
fresh peat (high DOC) decomposed peat (low DOC)flow routes(width = magnitude)
risin
ghy
drog
raph
peak
flow
falli
nghy
drog
raph
C-Q
rela
tions
hip
Lehstenbach Haean
Time series of Q and DOC from the outlet of the Lehstenbach catchment
Haean catchment (0.4 km2)
Lehstenbach catchment (4.2 km2)
Rappbode catchment (44 km2)
Q [m3/s] DOC-Q relationships for 3 events of different intensity (from Jeong et al. 2012)
Q [m3/s]
DOC
[mg/
l]
DOC-Q loops pooled for all 42 monitored events
We found:
Continuous DOC and Q data from three catchments of different size:
1) 1st-order catchment (0.4 km2) in the Haean watershed, South Korea, forested, monsoonal climate with intense runoff events
2) Lehstenbach catchment (4.2 km2), South-East Germany (Fichtelgebirge), forested with peat-forming riparian wetlands
3) Rappbode catchment (44 km2), Central Germany (Harz), mixed landuse, mainly forested
Results
References: Jeong J.J., Bartsch S., Fleckenstein J.H., Matzner E., Tenhunen J. Lee S.D., Park S.K., Park J.H. (2012) Differential storm responses of dissolved and particulate organic carbon in a mountainous headwater stream investigated by high-frequency in-situ optical measurements, Journal of Geophysical Research – Biogeosciences, 117, doi 10.1029/2012JG001999 Strohmeier S., Reichert M., Frei S., Knorr K.-H., Fleckenstein J.H., Peiffer S., Matzner E. (2013) Concentrations and fluxes of dissolved organic carbon in runoff from a forested catchment: insights from high frequency measurements, Biogeosciences,10:905-916
conceptual models
1) Department of Hydrogeology, Helmholtz Center for Environmental Research - UFZ, Leipzig, 2) University of Bayreuth, 3) University of Münster, 4) EWA Womans University, Seoul, South Korea
EGU2014-15385
