Doerthe Tetzlaff
Hydroecological interfaces between landscapes and riverscapes
integrated approaches and new insights in changing environments
Thanks to…
Chris Soulsby
Postdocs: Christian Birkel, Josie Geris, Jason Lessels, Genevieve Ali
PhDs: Jonathan Dick, Maria Blumstock, Claire Tunaley
International collaborators: John Bradford, Jim Buttle, Sean Carey, Hjalmar Laudon, Jeff McDonnell, Jim McNamara, Jan Seibert…
Investigating links between instream flow and biota has long history
HOWEVER: landscape scale hydrology controls variability in rivers and instream biosphere
Landscape influenced by landcover, environmental change etc..
Variables mediating stream flow: energy, vegetation, sub surface waters etc…
Linkages hydrosphere and biosphere
Outline
Need to understand fundamental science of ecological functioning
Management of riverscapes for human use and as living entity
Pre-requisite to sustainable management of
landscapes and riverscapes in an integrated way
Interference with riverscape at multiple scales
Aquatic /
Terrestrial
Seemingly “simple” research question in environmental hydrology
• How long does water reside in landscapes?
• What flowpath does water take to streams?
• Where is water stored?
• How does this affect water quality and instream ecology?
At different times, different parts of the landscape are connected and responsible for overall riverscape response and functioning
1) Use of environmental tracers to understand functioning of ecohydrological systems across scales
2) Use of a suite of novel, integrated approaches (high resolution LIDAR and GIS; multiple tracers; sensor technologies; tracer-
aided models) to understand connections and interlinkages between landscapes and riverscapes
3) Apply these approaches along cross-climatic gradients in intersite comparisons to understand environmental and climate changes.
Integrated approaches to understand functioning of landscapes and hydroecological interfaces
Outline
Tracers: Spatial process-understanding of connections and interfaces
Sayama and McDonnell, 2009 WRR
Mean daily flow [m3 s
-1]
0 1 2 3 4 5
Gra
n A
lka
linity [
µE
q l
-1]
0
200
400
600
800
Acidic soilwater
- Alkaline groundwater
Tracers for geographic sources
Outline
Tracers: Temporal process-understanding of connections and interfaces
Sayama and McDonnell, 2009 WRR
after McGuire and McDonnell, 2006
Tracers for flow paths and travel times
(change only through mixing)
9
Saturation zone under dry conditions
Saturation zone under wet conditions
Spatially and temporally dynamic connections
Typical catena sequence
Quasi-permantlysaturedhistosols
Freely-draining podzols
Outline
Geophysics: deeper subsurface
John Bradford, Boise State
Outline
Isotope dynamics: insights into flow paths and connections of landscapes and riverscapes
Wetlands as “isostats”
Wetland soils
Groundwater
-50
-65
-50-65
Streamwater: damping
Precipitation: strong variability
Tetzlaff et al., 2014, WRR
Spatially distributed transit times: importance of riparian zones as mixing zones
Waters from different sources across hillslope drain through large riparian storage and mixing zone
Tetzlaff et al. WRR, 2014
Tetzlaff et al., 2014, WRR
DOC as a tracer: dynamics strongly controlled by seasonal coupling and interlinkages
Large events: hillslope ‘switches on’ and contributes to DOC fluxes
Saturated area responsible for 60% of stream loads
Low flows: Importance of groundwater increases
Dick J, et al. (2015) Modelling landscape controls on Dissolved Organic Carbon sources and fluxes to streams. Biogeochemistry.
07/08 10/08 01/09 04/09 07/09 10/09
Air
te
mp
era
ture
(oC
)
-10
-5
0
5
10
15
20
25
Sa
tura
tio
n a
rea
exte
nt (%
)
0
10
20
30
40
50
FIO
./10
0m
l
1
10
100
1000
10000
Air temperature
% Saturation area
FIO
Faecal Indicator Organisms as tracers: linking seasonality and hydrological controls
FIO peaks are transient and episodic:
Summer: high biological productivity (reproduction) & short
periods of high connectivity - high transient FIO flux
Winter: low biological productivity (reproduction) - low FIO flux
regardless of connectivity
Tetzlaff et al., 2010, Hydrol. Processes.
Outline
GIS, LiDAR, geospatial models: interactions at high spatial resolution
794500
794700
794900
795100
795300
330400 330800 331200 331600Longitude
Latitu
de
795300
794500
794700
794900
795100
795300
330400 330800 331200 331600Longitude
La
titu
de
795300
Classification
Ground water
Mixed water
Soil water
Dry conditions: weak GW connection / more mixed signal (GW / hillslopes get disconnected)
Wet periods: highly connected, more dominant GW influence
Lessels J, et al. Water sources and mixing in riparian wetlands
revealed by tracers and geospatial analysis. Water Resources
Research. In review.
Outline
Sensor technologies: Dynamics at high temporal resolution
High-frequency DOC dynamics using fdom optical sensors
PhD Claire Tunaley
Periods of low hydrological dynamics
Event dynamics
Modelling controls on FIO: risk assessment
Flow AlkalinitySaturation area
Temperature
Mean daily flow [m3 s
-1]
0 1 2 3 4 5
Gra
n A
lkalin
ity [
µE
q l
-1]
0
200
400
600
800
01/99 05/99 09/99 01/00 05/00 09/00 01/01
Satu
ratio
n a
rea (
%)
0
20
40
60
07/08 10/08 01/09 04/09 07/09 10/09
Air te
mp
era
ture
(oC
)
-10
-5
0
5
10
15
20
25
1996 1999 2002 2005 2008
FIO
/ 1
00
ml
0.11
10100
100010000
Prediction FIO
Periods of High risk
Periods of Low risk
� Longer-term assessment of change in connectivity and contamination risk of FIO
Tetzlaff et al., 2010, Hydrol. Processes.
Tracer-aided models: integrated process understanding
Birkel et al., 2015, Hydrol. Proc.
Ecology and hydrology are coupled at every scale level
Multiple scale coupling – hydroecologicalcontinuity
Catchment scale (Local scale)
Hillslope scale
Instream hydraulics / Ecologicalhabitats
Cross-regional / global scale
Climate and landuse pressures
Small temperature change: precipitation as rain or snowwinter snow pack accumulationmelt rate
Implications: stream flow regimes; water quality; hydroecology(instream, terrestrial)
Pictures: http://www.climatechangenorth.ca/
Deforestation
Afforestation / crop
rotationRenewable energy Deforestration
Climate change implications for instream ecology
Highest at warmer sites with more variable flow regimes (higher, more frequent
spate events)
Future: if stream T increase and more rainfall-influenced flow regimes – change in
composition of macroinvertebrate communities: Plecopterans being “winners”
Plecoptera
Mean annual Temperature (oC)
2 3 4 5 6 7 8 9 10
2
4
6
8
10
12
M
G S
K
C
D
Hr=0.89, p<0.01
Estimated Plecoptera genera richness
Q50 (mm)
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
Estimated Plecoptera genera richness
2
4
6
8
10
12
M
G S
K
C
D
Hr=0.77, p<0.05
Abundance & diversity of stone flies (Plecoptera)
Kruitbos et al. Hydrobiologia, 2012.
Outline
Terrestrial ecology: importance of biosphere
Degree of mediation dependent on landscape structure
Response of vegetation communities: change in composition and distribution
Subsequent effects on ET and soil properties: alteration of partitioning of precipitation inputs, subsequent storage and release of water?
Photos: Phil Wookey, Stirling
1977
2010
Callaghan et al., 2011, Ambio.
Current
Climate change projections: Changes in biome type?
Projected changes
GCMs: impacts likely to be greatest at sites further north
E.g Wolf Creek (WC): warming temperatures affect disposition of forest through upward-migration of treeline
Systematic basis - conceptualising future changes in ecohydrology
Tetzlaff D et al. (2013) Catchments on the Cusp? Structural and functional change in northern ecohydrological systems. Hydrol. Proc.
Outline
What do deviations from the MWL tell us?The role of plants
Deviation (change in slope) compared to GMWL of water samples(stream, soils, plant xylem water): fractionation from meteoric water and influence of vegetation
Birkel and Soulsby, 2015, Hydrol. Proc.
Cross-regional comparison of isotope deviations
Wolf CreekGirnock
Krycklan
Tetzlaff D, et al. (2015) A preliminary assessment of water partitioning in northern headwaters using stable
isotopes and conceptual runoff models: challenges and open questions. Hydrological Processes.
Deviations show subtle effects of internal catchment
processes on isotopic fractionation (evaporation)
Snow & high % wetlands
“VeWa”: Isotopes to understand vegetation-water interlinkages
Isotopes as “fingerprints” of water
Many other opportunities…
- Helicopters / drones…- Fibre optics- …
Geophysics for imaging root water uptake
DO optical sensors (Birkel et al., 2013, WRR)
Linkages hydrosphere – biosphere are complex: importance of landscape processes controlling riperscapes
New, integrated approaches needed to understand hydroecological interfaces between landscapes and riverscapes:
integration of tracers, sensors, GIS, tracer-aided models…
Importance of inter-site comparison to contextualise individual findings and to assess implication in changing environments
Summary
Outline“how can we manage water for the benefit of mankind in nonstationary times when
we know so little about its various stores,
flow pathways and residence times even in a
developed country like the United States?”
Many thanks for your attention!!!
”The more closely we search, the more elusive the edge
becomes” (K. Dean Moore)