Post on 23-Feb-2016
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Watershed Delineation and Characteristics on Alaska’s North Slope
Matt KhoshUniversity of Texas at AustinDepartment of Marne Science
Arctic Ecosystems• Prevailing cold and wet climate promotes
long-term storage of atmospheric CO2
• Large pools of stored organic matter• In the context of climate change…???
CO2 N2O
CH4
Climate Change
Climate Change
Arctic Rivers
• High amounts of organic matter– DOM (dissolved organic matter)– Carbon and Nitrogen
• Sites of Biogeochemical transformations– Organic matter conduits– System loss pathways
• Organic matter dynamics and how it will be affected ???
Study Area
• “North Slope”• Above the Arctic
Circle• Soil frozen most
of the year– “active layer”
Arctic Rivers
5/21/20096/18/2009
Study Area
• Sampling Sites– 3 Mountain– 3 Tundra
•Watershed area ?
Study Sites
DEM approx. 40m x 40mStream delineation
value = 5000 cells
100m DEM Stream delineation = 1500
Area (km²)
Site 40m5000 FAC
100m1500 FAC % difference
Colville 58,587 58,728 -0.24%
Kuparuk 8,884 8,811 0.82%
Sagavanirktok 12,679 12,592 0.69%
Mackey (1996)
Watershed Attributes
• Topographic Primary Attributes–Computed directly from the DEM• Slope• Aspect• Plan and profile curvature• Flow path length• Upslope contributing area• Flow direction
100300
500700
9001100
13001500
17001900
21002300
25000%
10%20%30%40%50%
Colville
elevation (m)
100300
500700
9001100
13001500
17001900
21002300
25000%
10%20%30%40%50%
Kuparuk
elevation (m)
100300
500700
9001100
13001500
17001900
21002300
25000%
10%20%30%40%50%
Sagavanirktok
elevation (m)
5 10 15 20 25 30 35 400%
20%
40%
60%
80%
100%
Colville
Slope (%)5 10 15 20 25 30 35 40
0%
20%
40%
60%
80%
100%
Kuparuk
Slope (%)
5 10 15 20 25 30 35 400%
20%
40%
60%
80%
100%
Sagavanirktok
Slope (%)
2 4 6 8 10 12 14 16 18 20 20+0%
20%
40%
60%
80%
100%
Colville
Slope (%)2 4 6 8 10 12 14 16 18 20 20+
0%
20%
40%
60%
80%
100%
Kuparuk
Slope (%)
2 4 6 8 10 12 14 16 18 20 20+0%
20%
40%
60%
80%
100%
Sagavanirktok
Slope (%)
flat 30 60 90 1201501802102402703003303600%
3%
6%
9%
12%
15%
Colville
Aspect (deg. from North)flat 30 60 90 120150180210240270300330360
0%
3%
6%
9%
12%
15%
Kuparuk
Aspect (deg. from North)
flat 30 60 90 1201501802102402703003303600%
3%
6%
9%
12%
15%
Sagavanirktok
Aspect (deg. from North)
Watershed Attributes
• Secondary/Compound Attributes–Computed from a combination of primary
attributes–Physically based or empirically derived
indices–Characterize landscape spatial variability of
specific processes
Topographic Wetness
• Effects of topography on the location and size of saturated areas and areas of runoff generation– Surface saturation zones– Soil water content– Delineate vegetation
As = specific catchment area (m)[Upslope contributing area/cell width]
Β = slope gradient
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 23+
0%
5%
10%
15%
20%
25%
30%
Colville
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 23+
0%
5%
10%
15%
20%
25%
30%
Kuparuk
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 23+
0%
5%
10%
15%
20%
25%
30%
Sagavanirktok
Upslope Contributing Area
Future Work…
• Calculate TWI using the D-infinity model• Land-cover type distribution• Permafrost extent and or active layer depth
index
Questions ???