Flowpath or stream?: Reconciling the interaction of soil hydrology and stream function in the coastal temperate rainforest.

1. Flowpath or stream?: Reconciling the interaction
of soil hydrology and stream function in the
coastal temperate rainforest.
David D’Amore,
USDA Forest Service
Pacific Northwest Research Station
Juneau, Alaska

2. Hydropedology is the linkage between soil science and
hydrology that studies the multi-scale interaction
between pedologic and hydrologic properties of the
earth’s critical zone.

3. The functional response to structural
restoration measures is uncertain and
varies through time.

4. The Alaskan coastal temperate rainforest
(ACTR) is a sub-region of the perhumid
zone of the coastal temperate rainforest
biome that extends from northern California
to Prince William Sound.
Map courtesy of inforain:
www.Inforain.org

5. Stream: A body of
water with a current,
confined within a bed
and stream banks.

6. The riparian zone definition for the
coastal temperate rainforest is:
• “The area outside of the active
river channel that is influenced by
or influences the adjacent
terrestrial ecosystem”

7. The study of soil hydrology is concerned with:
1) The duration of saturation within a soil;
2) The flow routing or how water moves through
a system;
3) The quality of water that is derived from a
water source.

8. There are two key concepts for integrating
hydrology and biogeochemistry in the ACTR:
1) Hydropedology is the combination of soil science and
hydrology that studies the relationships between soil,
landscape, and hydrology.
2) Flowpath integration is the study of how the flowpath
of water and the material entrained in the flowpath
integrates stream and landscape heterogeneity.

9. Landscape hierarchies can partition the watershed into functional units.

10. The catena provides a good model for hydrologic
soil formation on hillslopes in the CTR.
Uplands
Typic Cryohumods
Forested Wetlands
Euic Terric Cryosaprists
Upper Backslope
Bogs
Dysic Typic Cryohemists
Lower Backslope
Footslope
Toeslope

11. The Juneau hydrologic observatory has three hydropedomorphic
systems replicated within three watersheds: sloping bogs,
forested wetlands, and uplands.

12. Water Balance:
Q=P-E-ΔS

13. Water, water everywhere….
The CTR receives an average of three
meters of precipitation per year.

14. 0.2
Type I 0.18
Precipitation
Discharge Discharge varies
with watershed
0.16
0.14
0.12
0.1
elevation, and slope
0.08
0.06
0.04
0.02
0
jan feb m ar apr m ay jun jul aug sep oct nov dec
Type II
0.2
0.18 Precipitation
0.16
Discharge
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
jan feb m ar apr m ay jun jul aug sep oct nov dec
Type III 0.2
0.18 Precipitation
0.16
Discharge
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
jan feb mar apr may jun jul aug sep oct nov dec

15. Distribution of Watershed Types Type I
in Southeast Alaska
# 1525
Area (km2) 17,870
Type 1 Mean elev (m) 142
Glacier Bay
National Park
Type 2 Mean max (m) 455
Type 3
Annual Q (km3) 42
Area not included in analyses
DOC flux (Tg) 0.29
JUNEAU
Mean % wetland 9.0
Type II
C A USA
NA
# 1213
DA
Area (km2) 28,456
Mean elev (m) 381
Mean max (m) 978
Sitka
Annual Q (km3) 95
Petersburg
DOC flux (Tg) 0.40
Mean % wetland 11.8
Pa
Type III
cif
ic
# 110
Oc
Area (km2) 19,962
ea
n
Mean elev (m) 857
Ketchikan
Mean max (m) 1846
Annual Q (km3) 70
DOC flux (Tg) 0.10
0 50 100
Mean % wetland 4.2
Kilometers

16. The coastal temperate rainforest is nearly
always in a state of moisture excess.
200 200
Precipitation
Evapotranspiration
150 150
P-PET
100 100
Ppt, ET (mm)
P-PET (mm)
50 50
0 0
-50 -50
-100 -100
ary ary rch April y
Ma Jun
e y t r r r
Jul ugus embe ctobe embe embe
r
J anu Febru Ma A ept O No v c
S De

17. Seasonal water table patterns vary across
the hydropedomorphic gradient.
10 Upland
Forested Wetland
Sloping Bog
0
Water Table Depth (cm)
-10
-20
-30
-40
-50
May Jun Jul Aug Sep Oct Nov

18. The production and export of dissolved organic carbon
is influenced by soil biogeochemical cycles.
30
Sloping Bog
Forested Wetland
25 Upland
20
DOC (mg C L-1)
15
10
5
0
May Jun Jul Aug Sep Oct Nov

19. The forested wetlands and bogs have distinct
seasonal patterns in water table depth.
0
-5 Water Tables
Water Table Depth (cm)
-10
-15
-20
-25
-30
Forested Wetland
Bog
-35
-40
ay
ly
ne
t
r
er
s
be
Ju
gu
ob
M
Ju
em
Au
ct
O
pt
Se

20. Soil saturation influences the biochemical
transformations in the soil profile.
-0.10 700
-0.15 Aerobic
600
Water table depth (cm)
-0.20
Redox potential (eH)
500
-0.25
-0.30
400
-0.35
Anaerobic 300
-0.40
Water Table Depth
Redox Potential
-0.45 200
Jun Jul Aug Sep Oct Nov Dec

21. All dissolved organic matter is not created equal.
Fluorescence Excitation
Emission Matrices (EEMs) PARAFAC
600
50
550
40
Relative % Contribution
500
30
Emission (nm)
450
20
400
10
350 0
1 2 3 4 5 6 7 8
Components
300
240 260 280 300 320 340 360 380 400 420 440
Excitation (nm)
Protein-like fluorescence (Tyrosine and Tryptophan-like)

22. Biodegradable DOC is related to protein,
which varies according to soil type.
50
A
40
BDOC (% C loss)
B B
30
C
20
60
10
50
BDOC (% of initial DOC)
0 40
Bog FW Fen Up
30
6.2 7.2 7.3 2.7 mg C L-1
20
10
0
0 10 20 30 40
Fellman et al., Biogeochemistry, 2008 Protein-like fluorescence
(% relative contribution)

23. Inlet Outlet
Reduced terrestrial organic
matter is oxidized during
processing in aquatic systems.
Miller et al., 2009, Fellman et al., 2009

24. Soil types can be arrayed by functional attributes
for evaluation of performance standards.
1.2
1.0
Fen Fen
Protein-like fluorescence
0.8 Fen
0.6
0.4
Axis 2
Bog
0.2
Bog
0.0 Upland Bog
Upland
-0.2
-0.4
FW
-0.6 FW FW
-0.8
-0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3
Axis 1
Humic-like fluorescence

25. Southeast Alaska has the
highest area weighted flux of
dissolved organic carbon in
the world.
14
12
Tongass
Mg C km-2 y-1
10 Amazon
Yukon
8
6
4
• Persistent fluxes of water
2 through soils provide a
0 terrestrial carbon pump to
streams.

26. The terrestrial and aquatic ecosystems are
intimately connected due to extensive shorelines.
Dissolved Organic Carbon Flux from
Southeast Alaska Rivers
Surface
Chlorophyll
Concentrations
Total DOC Flux, Tg/Year
Glacier Bay 0.000004 - 0.000353
National Park
during summer
0.000354 - 0.001013
0.001014 - 0.002728
0.002729 - 0.008332
JUNEAU Area not included in analyses
!
CA SA
NA
U
DA
!
Sitka
Petersburg
!
Pa
cif
ic
Oc
ea
n
!
Ketchikan
0
Æ 50 100
Kilometers

27. The North Pacific coastal fringe is a focal point for
changes in key environmental drivers such as
temperature and precipitation.
http://www.assessment.ucar.edu/modeling_scaling/img/future.gif

28. Predictions for temperature change show
increases for southeast Alaska, while predictions
for precipitation change show increases, but the
uncertainty in estimates for SE Alaska are high.

29. Evapotranspiration may expand the aerobic zone
of soils during times of soil moisture deficit.
0
Water Table Depth (cm)
-10
-20
-30
Sloping Bog
Forested Wetland
Forested wetland 2050
-40
May Jun Jul Aug Sep Oct Nov

30. The catotelm, or aerobic zone in surface soils
will increase during soil moisture deficit.
0
Water Table Depth (cm)
-10
-20
-30
Forested wetland
Sloping bog
Forested wetland 2050
-40
6/5/2006 6/12/2006 6/19/2006 6/26/2006

31. The water table
relationships can be
extraploated to the
watershed through soil
drainage class
categories.

32. Drainage classes
can be scaled to
finer landscape units
using digital
elevation models.

33. Flowpath models
can be applied
using water table
depths to array
classes in accurate
categories.

34. Hydropedologic studies can provide watershed models for: flow
routing, duration of saturation, quantitative hydrologic evaluations
and biogeochemical characterization.

35. Landscape wetland distributions can be
used for planning functions at broad scales.