Environmentally Threatened Communities Denali Commission

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Environentally Threatened Counities Denali Coission Perafrost Risk to Infrastructure Collaborators University of Alaska Fairbanks Institute of Northern Engineering (INE) Cold

1 Environentally Threatened Counities Denali Coission Perafrost Risk to Infrastructure Collaborators University of Alaska Fairbanks Institute of Northern Engineering (INE) Cold Regions Research and Engineering Lab (CRREL) ACCAP Alaska Cliate Webinar, March 2018 Bill Schnabel, Ph.D., P.E., Director UAF Institute of Northern Engineering

2 Scope and Objectives Collaboration between UAF, CRREL, and USACE. Funded by Denali Coission UAF and CRREL: Evaluate threat to infrastructure in AK counities iposed by thawing perafrost USACE: Evaluate threat to infrastructure in AK counities iposed by coastal/riverine erosion and flooding Focus new work upon threats based on flooding Utilize 2009 Baseline Erosion Assessent for erosion data UAF and CRREL: Integrate cobined threats iposed by perafrost, erosion and flooding into a noralized overall threat index iposed by the three cobined environental threats

3 Paraeters and Current Findings Desk-top analysis Analyzing for public infrastructure only Analyzing for current abient teperatures Perafrost thaw settleent is generally not catastrophic Public infrastructure (larger counities) is generally well constructed for current teperature regie Available perafrost aps are low spatial resolution Available technical inforation - low to none < 5% return on village perafrost condition surveys For any counities the best inforation are satellite iages Infrastructure resiliency to cliate waring generally unknown Analysis algorith = existing data + photos + tea knowledge

4 Alaska Perafrost Terrains Continuous Discontinuous Sporadic Modified fro Brown and others, 1998 by the U.S. Arctic Research Coission Perafrost Task Force Report (2003)

5 Risk is a Function of Ice Content Frozen alluvials (gravels) are generally low ice content generally low threat Yedoa (ice coplex) - considerable threat Photo by Go Iwahana

6 Perafrost Thaw Settleent M. Kanevskiy (2016)

7 Continuous perafrost zone: Yedoa occurs ainly in lowlands and foothills, unglaciated during the Late Pleistocene. Main Yedoa areas: Silt belt (Carter, 1988), located along the boundary between the Arctic Coastal Plain and Arctic Foothills, and northern part of the Seward Peninsula. Within poorly drained plains, Yedoa has been strongly reworked by therokarst lakes. Thawlake basins are uch less frequent in the foothills. Discontinuous perafrost zone: Yedoa occurs ainly in foothills and valleys within the uplands and low ountains, unglaciated during the Late Pleistocene. Main Yedoa areas: southern part of the Seward Peninsula and adjacent areas, Yukon-Tanana upland, parts of Yukon Flats adjacent to foothills. Within poorly drained plains (e.g., Yukon Flats, Koyukuk Flats, and Innoko Flats), Yedoa has been alost copletely reworked by therokarst and theral erosion. Yedoa renants exist ostly in the better drained areas adjacent to foothills or large river valleys. Sporadic perafrost zone: Yedoa-like terrain (supposedly yedoa hills and thaw-lake basins) was detected within Yukon- Kuskokwi delta and adjacent areas, but we have no confired evidence of yedoa occurrence in these areas. M. Kanevskiy (2016)

8 AI. Natural hazards: Therokarst and theroerosional processes, detected by analysis of aerial photos and satellite iagery 0. No detected perafrost features 1. Minor hazards No active therokarst and theroerosional features, rare relic inactive features ay be detected (e.g., vegetated thero-erosional gullies, depressions of possibly therokarst origin) 2. Moderate hazards Ice-wedge polygons with rare sall therokarst ponds, rare oderately active theroerosional gullies 3. Major hazards Wide-spread ice-wedge polygons with nuerous therokarst ponds above degrading ice wedges, active thero-erosional gullies 4. Extree hazards Active thaw slups with exposed ice-rich perafrost, nuerous deep therokarst ponds above large degrading ice wedges, deep active thero-erosional gullies A. Existing Perafrost-Related Probles B. Risks of Future Perafrost Degradation and Thaw Settleent AII. Docuented Distress based on counication with counity and aintenance personnel; analysis of existing reports and publications AIIa. Structures including schools, power plants, water / wastewater treatent plants, clinics 1. Cosetic Daage 2. Fundaental Daage 3. Minor Structural Daage 4. Major Structural Daage AIIb. Utilities including water / wastewater transission, power transission, etc. AIIc. Transportatio n including roads, streets and airports BI. Risk of perafrost degradation (depends on ground teperatures only) BII. Risk of thaw settleent (TS) of the ground surface during anticipated life of infrastructure as a result of perafrost degradation (occurs only if MAGT > 0 C) BIIa. For structures with shallow foundations Life = 50 years BIIb. For structures with deep foundations Life = 50 years 0. No docuented distress 0. No risk No perafrost 1. Minor distress to include inor oveent with no loss of service 2. Minor Daage requiring occasional shoring or inor repairs to restore service repair 3. Major daage requiring frequent shoring and ajor repairs to restore service 4. Major daage resulting in prolonged loss of service 1. Minor distress which results in occasional aintenance and loss of service 2. Distress requiring occasional aintenance beyond routine 3. Distress requiring frequent aintenance to insure service 4. Distress resulting in loss of service and ajor repairs 1. Low MAGT < -5 C (< -8 C for saline soils) 2. Moderate MAGT = -5-2 C (-8-5 C for saline soils) 3. High MAGT = -2 0 C (-5-3 C for saline soils) 4. Extreely high PF is currently degrading; MAGT > 0 C (> -3 C for saline soils) 1. Low TS < Moderate TS = High TS = Extreely high TS > Low TS < Moderate TS = High TS = Extreely high TS > 1.0 BIIc. For utilities Life = 30 years 1. Low TS < Moderate TS = High TS = Extreely high TS > 0.3 BIId. For roads and airports Life = 20 years 1. Low TS < Moderate TS = High TS = Extreely high TS > 2.0 BIII. Risk of differential TS > 1 due to ice-wedge therokarst and theral erosion not necessarily related to general PF degradation (ay occur when MAGT < 0 C) 0. No risk No ice wedges 1. Low Inactive ice wedges buried by thawstable peranently frozen soils >1 thick 2. Moderate Sall inactive or oderately active ice wedges 3. High Mediu size oderately active ice wedges 4. Extreely high Large active ice wedges near the surface

9 Risk of perafrost degradation (BI) (Possibility that MAGT at the perafrost table will exceed 0 C in the future) Yes No Thaw-susceptible soils Thaw-susceptible soils Yes No Yes No Occurrence of assive-ice bodies near the surface - No risk of thaw settleent (BII, BIII); - Risk level of perafrost degradation (BI) depends on initial MAGT Occurrence of assive-ice bodies near the surface Yes No Yes No - Risk level of general thaw settleent (BII) depends on the total aount of ground ice; - Risk level of differential thaw settleent caused by therokarst and theral erosion along ice wedges (BIII) depends on the aount and distribution of assive ground ice near the surface - Risk level of thaw settleent (BII) depends on the aount of ground ice; - No risk of differential thaw settleent caused by therokarst and theral erosion along ice wedges (BIII) - Risk level of therokarst and theral erosion along ice wedges (BIII) depends on the aount of wedge ice near the surface; - Foration of deep therokarst ponds ay cause perafrost degradation (BI) and consequent thaw settleent (BII) if MAGT under the pond exceeds 0 C - No risk of thaw settleent (BII, BIII) - No risk of perafrost degradation (BI)

10 Village Perafrost (PF) zone and PF thickness PF occurr ence 1 PF teperatu re (MAGT), C 5 Active-layer (AL) thickness, c; PF table, (for locations with lowered PF table) Soils, gravietric oisture contents (GMC), excess ice volue (EIV), salinity, etc. Report # (DOT base+) or other references Thicknes s of layer with excess ground ice (H), Thaw strain (T), unit fraction Massive ice: Wedge-ice volue (WIV), unit fraction; height of ice wedges (HIW), Thaw settleent (TS), 2 TS = WIV *HIW * (1 T) + T *H PF features detected on sat. iagery 3 Existing hazards: Hazard Mitigation Plans; pers.co., etc Adak Station No PF Afognak No PF U? Akhiok No PF U #18, 32, 1771, 2970: no PF? Akiachak Akiak Sporadic Willias 1970: PF <12 Sporadic probably no PF under the village. TLP #2822: ~0 U #2822: 2-4, or near surface (AL-?) Kenji: no PF? Willias 1970: PF <12 (alluviu), no details #33: no PF #2822: war i-poor PF in several b- holes (~20% of holes, fro thin layers to >6 ), soe excess ice in org.silt, GMC silt, silty sand (al.no data) Kenji no PF? #1773: airport - only seasonal frost (in one of 21 test pits, end July) #2523: no frozen ground Akutan (Akun Island) No PF U Kenji No PF DOT reports no PF Alakanuk Sporadic TP FS 1989: PF zone. ~0 to -0.5 #384,1743: Several eters FS 1989: >4.5 #19: PF in 10 of 59 b- holes (5 deep); peat and org.silt overly silt and silty sand; alost no excess ice, GMC 20-60%; #21: old runway i-rich org.soils #384: new runway: GMC in PF 25-35% - siilar to unfrozen, <10% vis.ice; in all holes with PF unfrozen fro 3-5 #1743: drilling in the village no PF in 2--deep test pits; includes Duane Miller s report frozen fro 1 to 2, soe excess ice (GMC<70%); includes school report no PF FS 1989 report: drilling logs in the appendix A soe frozen, with i-rich soils on top (IL) GMC<80%. SMP report 1993 soe soil and PF inforation. Wedges??? (N of the village) (2????) (0.2?) No assive ice? Village&airport floodplain, YK delta, alluvial sedients GE: village looks stable, TK (not very active) bogs, ponds?, trails, ebankents (?) Polygons???? (N of the village) The village is located within the floodplain of the Kuskokwi River, probably no perafrost under the village. (0.4?) Village&airport floodplain (Yukon delta) TK ponds, bogs (at soe places along ebankents) LHMP-2013: The Village has occasional elting perafrost daage which accelerates erosion daage along the Kuskokwi River ebankent. Ipacts all structure types throughout the counity. LHMP: No perafrost-related probles This hazard does not exist for the City. (Akiak LHMP 2013)? HMP: There is no written record defining perafrost ipacts for the City. However, the Planning Tea stated that periodic, uneven settling throughout the years within the City has daaged buildings and roads constructed in perafrost areas. perafrost daage occurs annually to those structures and roads located adjacent to the City s wetlands. (Alakanuk LHMP 2013)

11 # Village PF occurrence 1 PF teperature (MAGT) 2, C Thaw susceptibility of soils 3 Massive ice 4 Existing probles 5 Overall risk level Confidence level 6 1. Afognak U No PF No PF 3 Outside the PF region 2. Akhiok U No PF No PF 3 Outside the PF region 3. Akiachak TLP ~0 Low to Mediu IW??? Moderate (buildings, roads) Moderate 2 HMP: Occasional thawing PF daage; Ice wedges exist north of the village 4. Akiak U No PF No PF 3 Outside the PF region 5. Akutan U No PF No PF 3 Outside the PF region (Akun Island) 6. Alakanuk TLP -0.5 to 0 Low to Mediu (IL) No Moderate (buildings, roads) Moderate 2 HMP: PF daage occurs annually to those structures and roads near the City s wetlands 7. Alatna LP -0.5? High Large IW Moderate High 2 Yedoa? (Near Allakaket) 8. Aleknagik U N/A N/A N/A? No PF 2 Isolated PF zone; No HMP 9. Allakaket PTL? -0.5 to 0 Mediu Sall IW??? Moderate to severe (buildings) Moderate 2 Daage: ainly in Old Town; Ice-rich PF in the vicinity 10. Abler PTL -1 to 0 Low No? Low 1 No data on existing probles, not any reports Need ore data! 11. Anaktuvuk Pass PT -7 to -5 Low to Mediu Sall IW Moderate Moderate 1-2 Subsidence throughout the counity (e.g., areas along Main Street) Need ore data 12. Angoon U No PF No PF 3 Outside the PF region 13. Aniak TL? ~0 Low No No probles Low 2 Sporadic PF zone; Mostly unfrozen; HMP: No perafrost-related probles 14. Anvik TL ~0 Low No No probles Low 2 Discontinuous PF zone; Mostly unfrozen; CP-2004: No perafrost-related probles 15. Arctic Village P -4 to -3? IW??? Buried glacier ice???? Moderate to high?????? 1 No data on existing probles, alost no reports Need ore data! 16. Atka U No PF No PF 3 Outside the PF region 17. Atautluak PLT? -1 to 0 Mediu to high Sall IW??? Moderate Moderate to high 2 Nuerous sink holes throughout the counity 18. Atqasuk P ~-8 Mediu???? Mediu IW Moderate to severe (buildings, Moderate to high???? 1 No reports; actively degrading ice wedges Need data! roads, utilities) 19. Barrow PC -9 to -7 High Large IW Moderate to High 3 No HMP; actively degrading ice wedges severe? 20. Beaver TL??? -1 to 0? No assive ice?? Low to oderate? 0 No sufficient ground-ice info; No HMP Need data! 21. Belkofski U No PF No PF 3 Outside the PF region Notes

Counity Survey Provides opportunity to develop a list of assets and their condition for a baseline. Allows counity to provide feedback to the study.

13 Counity Survey Provides opportunity to develop a list of assets and their condition for a baseline. Allows counity to provide feedback to the study. Provides ground truthing of our procedures. Data collected Nuber and type of facilities Foundation type Condition Drainage and snow drifting Observed settleent due to thawing perafrost

14 Conclusions and Needs Counities located in Yedoa belts and areas of war perafrost (-2 C to > 0 C) are at risk or are experiencing perafrost thaw degradation YK Delta, portions of the Interior Soe correlation is anticipated when coparing risk for flooding, coastal erosion, and perafrost Syste needed for copilation and analysis of counity data preferably GIS forat Perafrost teperature data needed

15 Questions

Permafrost-influenced Geomorphic Processes

Section 4 Permafrost-influenced Geomorphic Processes Geomorphic processes vary greatly among ecoregions in northern Alaska, extending from the Beaufort Sea coast to the Brooks Range (Figure 4.1). Regional