Sagavanirktok River Spring Breakup Observations 2015

Alaska’s economy is strongly tied to oil production, with most of the petroleum coming from the Prudhoe Bay oil fields. Deadhorse, the furthest north oil town on the Alaska North Slope, provides support to the oil industry. The Dalton Highway is the only road that connects Deadhorse with other cities in Interior Alaska. The road is heavily used to move supplies to and from the oil fields. In late March and early April 2015, the Dalton Highway near Deadhorse was affected by ice and winter overflow from the Sagavanirktok River, which caused the road’s closure two times, for a total of eleven days (four and seven days, respectively). In mid-May, the Sagavanirktok River at several reaches flooded the Dalton from approximately milepost (MP) 394 to 414 (Deadhorse). The magnitude of this event, the first recorded since the road was built in 1976, was such that the Dalton was closed for nearly three weeks. During that time, a water station and several pressure transducers were installed to track water level changes on the river. Discharge measurements were performed, and water samples were collected to estimate suspended sediment concentration. Water levels changed from approximately 1 m near MP414 to around 3 m at the East Bank station, located on the river’s east bank (about MP392). Discharge measurements ranged from nearly 400 to 1560 m3/s, with the maximum measurement roughly coinciding with the peak. Representative sediment sizes (D50) ranged from 10 to 14 microns. Suspended sediment concentrations ranged from a few mg/L (clear water in early flooding stages) to approximately 4500 mg/L. An analysis of cumulative runoff for two contiguous watersheds—the Putuligayuk and Kuparuk—indicates that 2014 was a record-breaking year in both watersheds. Additionally, an unseasonable spell of warm air temperatures was recorded during mid-February to early March. While specific conditions responsible for this unprecedented flood are difficult to pinpoint, runoff and the warm spell certainly contributed to the flood event.ABSTRACT ..................................................................................................................................... i LIST OF FIGURES ....................................................................................................................... iii LIST OF TABLES .......................................................................................................................... v ACKNOWLEDGMENTS AND DISCLAIMER .......................................................................... vi CONVERSION FACTORS, UNITS, WATER QUALITY UNITS, VERTICAL AND HORIZONTAL DATUM, ABBREVIATIONS, AND SYMBOLS ............................................ vii ABBREVIATIONS, ACRONYMS, AND SYMBOLS ................................................................ ix 1 INTRODUCTION ................................................................................................................... 1 2 STUDY AREA ........................................................................................................................ 5 3 METHODOLOGY AND EQUIPMENT ................................................................................ 9 3.1 Ice Elevations Prior to Breakup (GPS Surveys)............................................................. 10 3.2 X-Band SAR Analysis ................................................................................................... 11 3.3 Water Levels .................................................................................................................. 12 3.4 Acoustic Doppler Current Profiler ................................................................................. 14 3.5 Discharge Measurements ............................................................................................... 15 3.6 Suspended Sediments ..................................................................................................... 17 4 RESULTS .............................................................................................................................. 18 4.1 Air Temperature ............................................................................................................. 18 4.2 Annual Precipitation ....................................................................................................... 20 4.3 Cold Season Precipitation .............................................................................................. 22 4.4 Warm Season Precipitation ............................................................................................ 23 4.5 Surface Water Hydrology............................................................................................... 27 4.5.1 Ice Elevations .......................................................................................................... 28 4.5.2 X-Band SAR Analysis ............................................................................................ 31 4.5.3 Water Levels ........................................................................................................... 37 4.5.4 Discharge Measurements ........................................................................................ 43 4.5.5 Additional Field Observations ................................................................................ 49 4.5.6 Cumulative Volumetric Warm Season Runoff ....................................................... 59 4.5.7 Suspended Sediment ............................................................................................... 63 5 CONCLUSIONS ................................................................................................................... 66 6 REFERENCES ...................................................................................................................... 68 7 APPENDICES ....................................................................................................................... 72 ii

Sagavanirktok River Spring Breakup Observations 2016

In 2015, spring breakup on the Sagavanirktok River near Deadhorse was characterized by high flows that destroyed extensive sections of the Dalton Highway, closing the road for nearly 3 weeks. This unprecedented flood also damaged infrastructure that supports the trans-Alaska pipeline, though the pipeline itself was not damaged. The Alaska Department of Transportation and Public Facilities (ADOT&PF) and the Alyeska Pipeline Service Company made emergency repairs to their respective infrastructure. In December 2015, aufeis accumulation was observed by ADOT&PF personnel. In January 2016, a research team with the University of Alaska Fairbanks began monitoring and researching the aufeis and local hydroclimatology. Project objectives included determining ice elevations, identifying possible water sources, establishing surface meteorological conditions prior to breakup, measuring hydrosedimentological conditions (discharge, water level, and suspended sediment concentration) during breakup, and reviewing historical imagery of the aufeis feature. Ice surface elevations were surveyed with Global Positioning System (GPS) techniques in late February and again in mid-April, and measureable volume changes were calculated. However, river ice thickness obtained from boreholes near Milepost 394 (MP394) in late February and mid-April revealed no significant changes. It appears that flood mitigation efforts by ADOT&PF in the area contributed to limited vertical growth in ice at the boreholes. End-of-winter snow surveys throughout the watershed indicate normal or below normal snow water equivalents (SWE 10 cm). An imagery analysis of the lower Sagavanirktok aufeis from late winter for the past 17 years shows the presence of ice historically at the MP393–MP396 area. Water levels and discharge were relatively low in 2016 compared with 2015. The mild breakup in 2016 seems to have been due to temperatures dropping below freezing after the flow began. Spring 2015 was characterized by warm temperatures throughout the basin during breakup, which produced the high flows that destroyed sections of the Dalton Highway. A comparison of water levels at the East Bank Station during 2015 and 2016 indicates that the 2015 maximum water level was approximately 1 m above the 2016 maximum water level. ii Maximum measured discharge in 2016 was approximately half of that measured in 2015 in the lower Sagavanirktok River. Representative suspended sediment sizes (D50) ranged from 20 to 50 microns (medium to coarse silt). An objective of this study was to determine the composition and possible sources of water in the aufeis at the lower Sagavanirktok River. During the winter months and prior to breakup in 2016, overflow water was collected, primarily near the location of the aufeis, but also at upriver locations. Simultaneously possible contributing water sources were sampled between January and July 2016, including snow, glacial meltwater, and river water. Geochemical analyses were performed on all samples. It was found that the overflow water which forms the lower Sagavanirktok aufeis is most similar (R2 = 0.997) to the water that forms the aufeis at the Sagavanirktok River headwaters (Ivishak River), thought to be fed by relatively consistent groundwater sources.ABSTRACT ..................................................................................................................................... i LIST OF FIGURES ........................................................................................................................ v LIST OF TABLES ......................................................................................................................... ix ACKNOWLEDGMENTS AND DISCLAIMER ........................................................................... x CONVERSION FACTORS, UNITS, WATER QUALITY UNITS, VERTICAL AND HORIZONTAL DATUM, ABBREVIATIONS, AND SYMBOLS ............................................. xi ABBREVIATIONS, ACRONYMS, AND SYMBOLS .............................................................. xiii 1 INTRODUCTION ................................................................................................................... 1 2 STUDY AREA ........................................................................................................................ 6 3 METHODOLOGY AND EQUIPMENT ................................................................................ 6 3.1 Aufeis Extent .................................................................................................................... 7 3.1.1 Field Methods ........................................................................................................... 7 3.1.2 Structure from Motion Imagery ................................................................................ 8 3.1.3 Imagery ..................................................................................................................... 8 3.2 Surface Meteorology ...................................................................................................... 10 3.3 Water Levels .................................................................................................................. 11 3.4 Discharge Measurements ............................................................................................... 13 3.5 Suspended Sediment ...................................................................................................... 16 3.6 Water Chemistry ............................................................................................................ 17 3.6.1 Sampling ................................................................................................................. 17 3.6.2 Trace Element Analysis .......................................................................................... 19 3.6.3 Data Analysis .......................................................................................................... 19 4 RESULTS .............................................................................................................................. 20 4.1 Air Temperature ............................................................................................................. 20 4.2 Wind Speed and Direction ............................................................................................. 29 4.3 Annual Precipitation ....................................................................................................... 30 4.4 Cold Season Precipitation .............................................................................................. 32 4.5 Warm Season Precipitation ............................................................................................ 36 4.6 Aufeis Extent .................................................................................................................. 40 4.6.1 Historical Aufeis at Franklin Bluffs ........................................................................ 40 4.6.2 Delineating Ice Surface Elevation with GPS and Aerial Imagery .......................... 46 4.6.3 Ice Boreholes .......................................................................................................... 55 iv 4.6.4 Ice Accumulation (SR50) ....................................................................................... 58 4.6.5 Ice Thickness and Volume ...................................................................................... 60 4.7 Surface Water Hydrology............................................................................................... 62 4.7.1 Sagavanirktok River at MP318 (DSS4) .................................................................. 67 4.7.2 Sagavanirktok River at Happy Valley (DSS3) ....................................................... 70 4.7.3 Sagavanirktok River Below the Ivishak River (DSS2)........................................... 73 4.7.4 Sagavanirktok River at East Bank (DSS5) Near Franklin Bluffs ........................... 76 4.7.5 Sagavanirktok River at MP405 (DSS1) West Channel .......................................... 85 4.7.6 Additional Field Observations ................................................................................ 86 4.8 Suspended Sediment ...................................................................................................... 87 4.9 Water Chemistry ............................................................................................................ 91 5 CONCLUSIONS ................................................................................................................... 96 6 REFERENCES ...................................................................................................................... 99 7 APPENDICES ..................................................................................................................... 10

Negative Interest Rate Policies: Sources and Implications

Against the background of continued growth disappointments, depressed inflation expectations, and declining real equilibrium interest rates, a number of central banks have implemented negative interest rate policies (NIRP) to provide additional monetary policy stimulus over the past few years. This paper studies the sources and implications of NIRP. We report four main results. First, monetary transmission channels under NIRP are conceptually analogous to those under conventional monetary policy but NIRP present complications that could limit policy effectiveness. Second, since the introduction of NIRP, many of the key financial variables have evolved broadly as implied by the standard transmission channels. Third, NIRP could pose risks to financial stability, particularly if policy rates are substantially below zero or if NIRP are employed for a protracted period of time. Potential adverse consequences include the erosion of profitability of banks and other financial intermediaries, and excessive risk taking. However, there has so far been no significant evidence that financial stability has been compromised because of NIRP. Fourth, spillover implications of NIRP for emerging market and developing economies are mostly similar to those of other unconventional monetary policy measures. In sum, NIRP have a place in a policy maker's toolkit but, given their domestic and global implications, these policies need to be handled with care to secure their benefits while mitigating risks

Physical, cognitive, social and mental health in near-centenarians and centenarians living in New York City: findings from the Fordham Centenarian Study

BACKGROUND: Despite their strong increase, the population of the very old, including near-centenarians and centenarians, represent an unstudied and underserved population. Available studies mostly concentrate on predictors of exceptional longevity, but rarely extend their focus to other areas of functioning. Also, little is known about what contributes to experiencing a quality life in very old age. The present population-based study aims at providing a comprehensive picture of key domain of functioning, including physical, cognitive, social and mental function in very old individuals and to determine predictors of mental health indicators. METHODS: A total of 119 individuals aged 95 to 107 living in private dwellings and residential care facilities were recruited based on the New York City Voters Registry. Participants answered questions regarding their health and activities of daily living. Their cognitive functioning was determined using the Mini-Mental State Examination and the Global Deterioration Scale. Social resources were measured with number of children and the Lubben Scale. Mental health was assessed with the Geriatric Depression Scale and the Satisfaction with Life Scale. RESULTS: An unexpectedly large proportion of the sample lived in the community. On average, cognitive functioning was high. Although five diseases were reported on average, participants reported good health. Functional status was reduced. Most participants had at least one person for communication/social support. On average, depression was below cut-off, and most participants reported high life satisfaction. Regression analyses indicated that individual differences in depression were associated with subjective health, IADL and relatives support. For life satisfaction, subjective health, ADL and number of children were most important. Demographic characteristics, number of illnesses or cognitive status were not significant. CONCLUSIONS: Despite reduced levels of physical functioning and social resources, very old participants were in good mental health suggesting high resilience and ability to adapt to age-associated challenges. That a large proportion of them lived in the community further highlights their desire for leading an autonomous life, which may have been facilitated by New York service culture. More research is necessary to provide guidance for the development of well-suited services for this very old population