May 29, 2013 Field Trip Report
Susitna-Watana Ice Processes Study
Date: May 29, 2013
Crew: Robin Beebee and Lynn Spencer (HDR Alaska); pilot Alicen Bishop (JayHawk Aviation)
Talkeetna Weather: Sunny, clear, 82 degrees Fahrenheit (F) high and 42 degrees F low.
Objectives: Breakup observations and video river from mouth to Oshetna confluence.
Data Collected:
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Georeferenced photographs
Video
GPS points with ice and breakup observations
Ice floe and ice jam thicknesses
Retrieve cards from time-lapse cameras
Flight Path: The team departed Merrill Field at 1020 hours and flew directly to Su Station.
Flathorn Lake had backflooding from the Susitna River with dirty water. Flew up Susitna River
to Deshka Landing and then returned directly to Merrill at 1910 hours.
Lower River Observations
The remaining ice jams in the Lower River had cleared and all channel braids were flowing clear
except for minor shorefast ice and flowing ice. The Lower River appeared to be flowing
bankfull, but not overbank. Numerous small ice floes and some logs were coming down the
river. The gauges at Su Station and downstream confirmed that the stage was the highest since
the flood peak last fall (Figure 1).
Yentna River: The Yentna River was high but not flooding. Most of the gravel bars were covered
but the islands were not flooded (Figure 2).
Kroto Slough and Deshka River: There was no visible shore ice or ice in the river with the
exception of floating ice chunks. All the snow was gone. There were small log rafts, jams, and
floating debris in the river (Figure 3, Figure 4)
Camera Site RM59 (PRM64.1): At 1145 hours the team landed at the bottom of the island and
retrieved the camera card without incident (Figure 5, Figure 6).
Camera Site Birch Creek 1: The site was too flooded to land (Figure 7).
Camera Site Birch Creek 2: The team was able to land and retrieve the camera card. The water
was high but not flooding; there were still some sand bars visible (Figure 8, Figure 9).
Talkeetna Area: The Talkeetna River was high at near bankfull and flooding side channels near
town (Figure 11, Figure 12). At the confluence of the Talkeetna River and the Susitna main
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channel there was a lot of grounded ice on ice shelves. Shore ice right around Talkeetna on the
Susitna was minimal. The Chulitna River still had gravel bars visible but the braidplain was
mostly clear of ice.
Middle River Observations
Above Devil Canyon: Ice jam remnants were hanging on side channels and banks up past the
Dam Site. All tributaries were clear of ice except for some shore ice.
Below Devil Canyon: Ice jam remnants remained in side channels, on islands, and in the trees in
places between Talkeetna and Slough 21. The river appeared to be flowing bankfull and bringing
ice chunks and trees down with it – rumors of ice jams still holding proved to be false. The
largest jam remains were between Whiskers Slough and Slough 6A, in side channels around
Slough8A, and all over the Slough 9 area. Ice jams remained in Slough 21 side channels, but did
not appear to be overbank. Small tributaries were full of snowmelt runoff. Indian River still had a
little shore ice, but Portage Creek was clear and running high.
Whisker Slough: Ice was jammed up near Whisker Slough in the east side channel and on islands
(Figure 13). There was still some ice in the slough itself but it was clearing out (Figure 14).
Slough 6A was open except for a small ice flow at the mouth. There was a lot of stranded ice
chunks on the shores of the main channel upstream and downstream of Slough 6A (Figure 16
and Figure 17).
Curry Station Camera Site: The camera was still there, but the team was unable to land. There
was ice damage to an island in the middle of the main channel (Figure 18).
Slough 8A–Camera Site: There were numerous boulder piles 2-3 feet high on the island. Trees
had been uprooted and fallen from the river. The head of the island had large ice blocks up in the
vegetation but not above the tree line. Ice was pushed up against the camera tree (Figure 19 and
Figure 20).
Slough 9: There was a large ice jam at Slough 9. Ice was up in the trees and trees had been
knocked down. The beaver dam was still intact. Islands upstream of the slough had been over run
by debris and ice (Figure 21, Figure 22, and Figure 23).
Slough 11: The camera was intact on the island. There were large cobbles and boulders deposited
in the middle of the island. The slough itself was overtopped with some ice crowding in from the
main channel.
Indian River: There was still some ice on the gravel bars in Indian River (Figure 24).
Slough 21 – Camera Site: There was not enough freeboard to land at the camera site and the ice
on the upstream end of the island looked very unstable (Figure 25).
Portage Creek: There were numerous waterfalls raging with runoff from Portage Creek up
through Devil Canyon (Figure 26 and Figure 27).
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Dam Site: The team could not land at the Dam Site. The water was too high on the island with
ice on the upstream end (Figure 28).
Upper River Observations
The main channel of the Upper River was clear of ice but quite a bit of shorefast ice and ice jam
remnants surrounded the main channel and were in the trees on banks. All Upper River
tributaries below Oshetna were clear and running high.
Deadman Creek was raging and the falls were spectacular (Figure 29). Kosina Creek was
running high and had numerous ice chunks grounded on the edges (Figure 30). The remainder of
the upper river had large ice shelves and stranded ice in side channels and shores (Figure 31 and
Figure 32).
Representative Photographs
Figure 1. Su Station camera site, PRM 30.1.
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Figure 2. Yentna confluence, PRM 31.
Figure 3. Kroto Slough, PRM 44.3.
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Figure 4. Grounded ice, PRM 60.
Figure 5. Camera location – rustic wilderness side channel, PRM 64.2.
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Figure 6. Camera location – rustic wilderness side channel, PRM 64.2.
Figure 7. Camera location – Birch Creek 1, PRM 91.4. Flooded, log jams, and scour. Did not land.
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Figure 8. Camera location – Birch Creek 2, PRM 92.3.
Figure 9. Camera location – Birch Creek 2, PRM 92.3.
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Figure 10. Flooding near Trapper Creek, PRM 97.2.
Figure 11. Talkeetna River, PRM 100.2.
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Figure 12. High water at Talkeetna, PRM 100.2.
Figure 13. Ice jammed near Whisker Slough, PRM 104.9.
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Figure 14. Whisker Slough, PRM 104.9.
Figure 15. Near PRM 106.8, near Talkeetna Station.
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Figure 16: Ice jam –Slough 6A, PRM 115.5.
Figure 17: High water near Slough 6A, PRM 115.5.
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Figure 18. Ice jam near Curry Station, PRM 124.4.
Figure 19: Islands flooded Slough 8A, PRM 127.9.
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Figure 20. Slough 8A, PRM 127.9.
Figure 21. Ice jams at Slough 9A, PRM 132.4.
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Figure 22. Slough 9, PRM 132.4
Figure 23. Near PRM 132.4, Slough 9.
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Figure 24. Near Indian River, PRM 141.4.
Figure 25. Slough 21 camera sight, PRM 144.4.
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Figure 26. Falls in Tributary to Devil Canyon, PRM 159.2.
Figure 27. Devil Canyon, PRM 165.5.
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Figure 28. Dam Site Camera Island, PRM 185.8.
Figure 29. Deadman Creek Falls, PRM 189.4.
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Figure 30. Mouth of Kosina Creek, PRM 209.2.
Figure 31. Upper River remnants of ice shelves and stranded ice, PRM 219.3.
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Figure 32. Upper River remnants of ice shelves and stranded ice, PRM 222.
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