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)