May 11, 2013 Field Trip Report
Susitna-Watana Ice Processes Study
Date: May 11, 2013
Crew: Robin Beebee and Mark Doner (HDR Alaska); pilot Alicen Bishop (Jayhawk Aviation)
Talkeetna Weather: Overcast, temperatures varied from 34 to 60 degrees Fahrenheit (F), wind
NNE less than 10 mph.
Objectives: Video Susitna River; observe breakup progress.
Data Collected:



Photos (JPEG) with GPS points
Georeferenced video
Ice jams, ice bridges, open lead locations, some notable tributaries and other noteworthy
locations marked with GPS points
Summary: The air temperature on the Lower and Middle Susitna River during the previous two
nights was above freezing most of the night, and daytime temperatures had risen into the 50s.
Most of the Susitna River had meltwater on the ice cover, and gravel bars downstream of
Talkeetna were starting to appear from underneath the snow. The ice cover was clearly
weakening and the river was slowly rising, but the vast majority of the snow has yet to melt.
Forecast temperatures over the next 4-5 days are cooler than average (overcast in the high 40s)
which will slow the rate of melt and allow more of the ice cover to decay in place.
Downstream of the Yentna there was open water on each side of the main channel, but there
were no signs of movement in the ice cover. Alexander Slough was mostly open after the first
1/3 mile. The Yentna River was still frozen. Rolly Creek was mostly open upstream of an ice
jam at the Susitna River confluence. Upstream of the first half mile, ice cover on the Deshka
River had broken up since May 7, 2013. The Kashwitna River had continued melting and was
about 50 percent ice covered. Upstream of Sunshine Bridge, numerous open leads had opened in
the main channel of the Susitna River.
The ice jam at the mouth of the Talkeetna River that was present on May 7, 2013 was broken up.
There were ice jams forming at the confluence of the Chulitna and Susitna Rivers.
Leads on the middle river have continued to grow and there was a considerable amount of
overflow. Thermal leads at side sloughs were extending further into the main channel. The
Indian River was mostly open, up from 75 percent covered on May 7, 2013. Upstream of Devil
Canyon the river was mostly ice covered with growing intermittent leads and some overflow.
Flight Path: The team departed Merrill Field at 1025 hours and flew to the mouth of the Susitna.
They flew up the west channel, paralleling Alexander Slough, then up the main channel to
Flathorn Lake. They then flew down to the mouth of Fish Creek and back up the main channel to
the Deshka River. The team then flew up the Deshka River, noting open water and ice jams,
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 1
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
returned to the Susitna River and followed the river to Talkeetna where they stopped for fuel and
video camera battery/memory card change. After take off, the team retraced a couple of miles
downstream to pick up video footage of this section of river. They followed the river upstream to
the confluence with the Oshetna River, landed, took pictures and serviced the video camera.
Then they flew directly to Curry Station, landed, and took some snow depth measurements. After
taking measurements, they flew up over Curry Ridge to take some photos of potential telemetry
antenna sites and then returned to Talkeetna for fuel, at which time they then followed the lower
river downstream to the transmission lines and then returned to Anchorage, landing at Merrill
Field at 1713 hours. The flight included a marked increase in air traffic compared to earlier
winter flights, especially around Talkeetna and on the Middle and Upper River.
Lower River Observations
Mouth to Yentna River Confluence: The Susitna River downstream of the Yentna River has open
water on each side of the ice cover in the main channel, though the ice cover had not yet shown
signs of movement (Figure 1). Susitna Station had an open lead along the left bank (Figure 2).
Alexander Slough was ice covered for the first 1/3 mile. The slough and Alexander Creek were
both mostly open with a few jams up to Dinglishna Hill. Upstream of Dinglishna Hill, Alexander
Creek was still ice-covered (Figure 2 through Figure 6).
Yentna River to Sunshine Bridge: The Yentna River was still ice-covered, with a little more
overflow than May 8, 2013 (Figure 7). Open leads continue to widen on the main channel of the
Susitna River, with increasing amounts of meltwater flowing and stationary on top of the ice
(Figure 8 through Figure 11) Rolly Creek was mostly open, with an ice jam near the confluence
with the Susitna River. The Deshka River was ice-covered for the first half mile, then mostly
broken up with numerous jams in meander bends (Figure 12 through Figure 16). There was
minor flooding of riparian vegetation around jams. The Kashwitna River was still about
50 percent ice-covered. Rabideux Creek has an ice jam in the lower ¼ mile and was open
upstream (Figure 17).
Sunshine Bridge to Talkeetna: From Sunshine Bridge to Talkeetna there were numerous open
leads in the main channel Susitna River with intermittent accumulations of broken ice and ice
bridges (Figure 18).
Talkeetna and Chulitna rivers: The Talkeetna River was open to the confluence with the Susitna.
Ice floes that were jammed at the mouth on May 8, 2013) have cleared. The Chulitna River has
minor accumulations of broken ice jammed at its confluence with the Susitna. The Chulitna
River was already visibly siltier than the Susitna River (Figure 19).
Middle River Observations
Talkeetna to Gold Creek Bridge: The Susitna River from Talkeetna to Whisker Slough has
numerous open leads, and intermittent solid bridges/ice accumulations. The Middle Susitna
River below Devil Canyon has many leads in the main channel that were getting larger and there
was a lot of visible overflow, (Figure 20 through Figure 22). Thermal leads from side sloughs
were extending further downstream of slough mouths, sometimes a mile or more. The team
watched one jam dislodge and move downstream before stopping against the solid ice cover
downstream at Curry Camp (Figure 23, Figure 24).
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 2
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Gold Creek Bridge to Portage Creek: The Indian River confluence was mostly open (Figure 25).
Gravel bars were mostly snow covered, with snow depth between 2-3 feet over the gravel bar at
Curry Camp. Portage Creek was mostly ice covered with a small amount of new overflow near
the mouth (Figure 26).
Portage Creek to Dam Site: Devil Canyon was open except for 4-5 small jams. From Devil
Canyon to the Dam Site the river was mostly ice-covered with some long, intermittent open leads
in the main channel (Figure 27, Figure 28). There was more overflow on top of the ice than the
last survey (May 8, 2013). The gravel bars were still snow covered.
Upper River Observations
The Upper River was largely ice covered, with some open water on the ice cover as noted near
Kosina Creek (Figure 29, Figure 30). There were no major changes from the May 8, 2013 flight.
The snow cover on a gravel bar near the Oshetna confluence was 2-3 feet deep. The snow was
rotten enough that snowshoes were an impediment to travel. Significant snow coverage remains
in the mountains around the upper river (Figure 31).
Representative Photographs
Figure 1. Mouth of Susitna River, PRM 6.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 3
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 2. Susitna Station, PRM 30.
Figure 3. Alexander Slough, PRM 11.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 4
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 4. Mixing on Alexander Creek/Slough, PRM 13.5.
Figure 5. Open water on lower Alexander Creek.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 5
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 6. Alexander Creek, looking downstream 4.5 miles up from Alexander Slough.
Figure 7. Yentna River Confluence, PRM 31.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 6
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 8. Meltwater on the Lower Susitna River, PRM 47.
Figure 9. Ice jam whirlpool on the Lower Susitna River, PRM 27.4.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 7
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 10. Main channel of the Susitna River downstream of Montana Creek, PRM 78.
Figure 11. Main channel upstream of Sunshine Bridge, PRM 90.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 8
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 12. Deshka River, PRM 45.1.
Figure 13. Ice jams on Deshka River 3.3 miles upstream of the Susitna River confluence.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 9
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 14. Ice jam on the Deshka River 6.6 miles upstream of the Susitna River confluence.
Figure 15. Ice jams on the Deshka River 11.8 miles upstream of the Susitna River confluence.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 10
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 16. Ice jams on tributary to the Deshka River 17 miles upstream of the Susitna River confluence.
Figure 17. Rabideux Creek confluence, PRM 87.5.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 11
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 18. Sunshine Creek, PRM 88.
Figure 19. Ice jam at the confluence with Chulitna River.
Note the high levels of silt from the Chulitna, PRM 101.8.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 12
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 20. Ice deterioration on the main channel of the Middle River, PRM 110.
Figure 21. Ice jam on the Middle River, PRM 119.7.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 13
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 22. Ice jam at Gold Creek rail bridge, PRM 140.
Figure 23. Ice jam above Curry Station looking upstream, PRM 124.2.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 14
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 24. Ice jam above Curry Station looking downstream, PRM 124.2.
Figure 25. Ice jam at Indian River confluence, PRM 142.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 15
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 26. Portage Creek confluence, PRM 152.2.
Figure 27. Ice jam in lower Devil Canyon, PRM 154.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 16
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 28. Ice bridges in Devil Canyon, PRM 163.5.
Figure 29. Susitna River between Devil Canyon and Watana Canyon, PRM 170.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 17
Alaska Energy Authority
Draft: August 8, 2013
FIELD TRIP REPORT
SUSITNA-WATANA ICE PROCESSES STUDY
Figure 30. Kosina Creek 1.2 miles upstream from confluence.
Figure 31. Snow cover in the upper Susitna River drainage.
Susitna-Watana Hydroelectric Project
FERC Project No. 14241
Page 18
Alaska Energy Authority
Draft: August 8, 2013