31 research outputs found
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.
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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
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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
Hydrology and Meteorology of the Central Alaskan Arctic: Data Collection and Analysis
The availability of environmental data for unpopulated areas of Alaska can best be described as
sparse; however, these areas have resource development potential. The central Alaskan Arctic
region north of the Brooks Range (referred to as the North Slope) is no exception in terms of
both environmental data and resource potential. This area was the focus of considerable oil/gas
exploration immediately following World War II. Unfortunately, very little environmental data
were collected in parallel with the exploration. Soon after the oil discovery at Prudhoe Bay in
November 1968, the U.S. Geological Survey (USGS) started collecting discharge data at three
sites in the neighborhood of Prudhoe Bay and one small watershed near Barrow. However, little
complementary meteorological data (like precipitation) were collected to support the streamflow
observations. In 1985, through a series of funded research projects, researchers at the University
of Alaska Fairbanks (UAF), Water and Environmental Research Center (WERC), began
installing meteorological stations on the North Slope in the central Alaskan Arctic. The number
of stations installed ranged from 1 in 1985 to 3 in 1986, 12 in 1996, 24 in 2006, 23 in 2010, and
7 in 2014. Researchers from WERC also collected hydrological data at the following streams:
Imnavait Creek (1985 to present), Upper Kuparuk River (1993 to present), Putuligayuk River
(1999 to present, earlier gauged by USGS), Kadleroshilik River (2006 to 2010), Shaviovik River
(2006 to 2010), No Name River (2006 to 2010), Chandler River (2009 to 2013), Anaktuvuk
River (2009 to 2013), Lower Itkillik River (2012 to 2013), and Upper Itkillik River (2009 to
2013). These catchments vary in size, and runoff generation can emanate from the coastal plain,
the foothills or mountains, or any combination of these locations. Snowmelt runoff in late
May/early June is the most significant hydrological event of the year, except at small watersheds.
For these watersheds, rain/mixed snow events in July and August have produced the floods of
record. Ice jams are a major concern, especially in the larger river systems. Solid cold season
precipitation is mostly uniform over the area, while warm season precipitation is greater in the
mountains and foothills than on the coastal plain (roughly 3:2:1, mountains:foothills:
coastal plain).The results reported here are primarily for the drainages of the Itkillik, Anaktuvuk,
and Chandler River basins, where a proposed transportation corridor is being considered. Results
for 2011 and before can be found in earlier reports.ABSTRACT ..................................................................................................................................... i
LIST OF FIGURES ........................................................................................................................ v
LIST OF TABLES .......................................................................................................................... x
ACKNOWLEDGMENTS AND DISCLAIMER ........................................................................ xiii
CONVERSION FACTORS, UNITS, WATER QUALITY UNITS, VERTICAL AND
HORIZONTAL DATUM, ABBREVIATIONS, AND SYMBOLS ........................................... xiv
ABBREVIATIONS, ACRONYMS, AND SYMBOLS .............................................................. xvi
1 INTRODUCTION ................................................................................................................... 1
2 PRIOR RELATED PUBLICATIONS .................................................................................... 5
3 STUDY AREA ........................................................................................................................ 7
4 PREVIOUS STUDIES .......................................................................................................... 11
5 METHODOLOGY AND EQUIPMENT .............................................................................. 15
5.1 Acoustic Doppler Current Profiler ................................................................................. 17
5.2 Discharge Measurements ............................................................................................... 17
5.3 Suspended Sediments ..................................................................................................... 20
5.3.1 River Sediment ........................................................................................................ 21
5.3.2 Suspended Sediment Observations ......................................................................... 21
5.3.3 Suspended Sediment Discharge .............................................................................. 22
5.3.4 Turbidity ................................................................................................................. 23
5.3.5 Bed Sediment Distribution ...................................................................................... 23
5.3.6 Suspended Sediment Grain-Size Distribution ........................................................ 24
6 RESULTS .............................................................................................................................. 25
6.1 Air Temperature and Relative Humidity ........................................................................ 25
6.2 Wind Speed and Direction ............................................................................................. 30
6.3 Net Radiation .................................................................................................................. 38
6.4 Warm Season Precipitation ............................................................................................ 40
6.5 Cold Season Precipitation .............................................................................................. 46
6.6 Annual Precipitation ....................................................................................................... 52
6.7 Soil ................................................................................................................................. 55
6.7.1 Soil Temperature ..................................................................................................... 56
6.7.1.1 Results ................................................................................................................. 57
6.7.2 Soil Moisture ........................................................................................................... 60
6.7.2.1 Results ................................................................................................................. 61
6.8 North Slope Climatology ............................................................................................... 63
6.8.1 Air Temperature ...................................................................................................... 63
6.8.2 Precipitation ............................................................................................................ 65
6.8.2.1 Warm Season Precipitation ................................................................................. 65
6.8.2.2 Cold Season Precipitation ................................................................................... 68
6.8.2.3 Annual Total Precipitation .................................................................................. 70
6.9 Surface Water Hydrology ............................................................................................... 72
6.9.1 Itkillik River ............................................................................................................ 73
6.9.2 Upper Itkillik River ................................................................................................. 74
6.9.2.1 Dye Trace Results, Upper Itkillik River .............................................................. 81
6.9.3 Lower Itkillik River 2013 Breakup and Spring Flood ............................................ 84
6.9.4 Anaktuvuk River ..................................................................................................... 91
6.9.5 Chandler River ...................................................................................................... 100
6.9.6 Additional Field Observations .............................................................................. 107
6.10 River Sediment Results ................................................................................................ 117
6.10.1 Correlation between Isco and Depth-Integrated Samples ..................................... 117
6.10.2 Suspended Sediment Rating Curves ..................................................................... 118
6.10.3 Suspended Sediment Concentrations .................................................................... 119
6.10.4 Suspended Sediment Discharge ............................................................................ 125
6.10.5 Turbidity ............................................................................................................... 129
6.10.6 Bed Sediment Distribution .................................................................................... 134
6.10.7 Suspended Sediment Grain-Size Distribution ...................................................... 136
7 HYDROLOGIC ANALYSIS .............................................................................................. 139
7.1 Precipitation Frequency Analysis ................................................................................. 139
7.2 Manning’s Roughness Coefficient (n) Calculations Revisited .................................... 142
7.3 Hydrological Modeling ................................................................................................ 147
8 CONCLUSIONS ................................................................................................................. 157
9 REFERENCES .................................................................................................................... 163
10 APPENDICES ..................................................................................................................... 169
Appendix A – Air Temperature and Relative Humidity
Appendix B – Wind Speed and Direction: Wind Roses
Appendix C – Cumulative Warm Season Precipitation for All Years at Each Station and
Cumulative Warm Season Precipitation by Year for All Stations, 2007 to 2013
Appendix D – Soil Temperature and Moisture Content
Appendix E – Rating Curves and Discharge Measurement Summarie
Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity
Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.Animal science
Estimating the 3D Motion and Morphology of Line-like Structures from Orthogonal Projections
In image processing, the tracking of visible objects through time is a very common task. This task normally requires the definition of the object boundaries in order to describe its motion. However, that approach not always gives su#cient information about the position of specific points located on the surface of the object, especially in case the shape of the object also changes. Using additional information and making some simplifying assumptions can solve this general and mathematically ill-posed problem. In this research, the problem is restricted to the assessment of the motion and morphology of line-like 3D-structures (lines or tubes) by tracking the positions of small segments of such structures in two orthogonal projections. The method is based upon several assumptions regarding the physical properties of the real-world object. A typical (biomedical) application is the tracking of arteries for subtraction angiography and densitometric measurements. Keywords--- motion estimatio..
The Biobank of Nephrological Diseases in the Netherlands cohort: the String of Pearls Initiative collaboration on chronic kidney disease in the university medical centers in the Netherlands
Despite advances in preventive therapy, prognosis in chronic kidney disease (CKD) is still grim. Clinical cohorts of CKD patients provide a strategic resource to identify factors that drive progression in the context of clinical care and to provide a basis for improvement of outcome. The combination with biobanking, moreover, provides a resource for fundamental and translational studies. In 2007, the Dutch government initiated and funded the String of Pearls Initiative (PSI), a strategic effort to establish infrastructure for disease-based biobanking in the University Medical Centres (UMCs) in the Netherlands, in a 4-year start-up period. CKD was among the conditions selected for biobanking, and this resulted in the establishment of the Biobank of Nephrological Diseases-NL (BIND-NL) cohort. Patients with CKD Stages 1-4 are eligible. The data architecture is designed to reflect routine care, with specific issues added for enrichment, e.g. questionnaires. Thus, the collected clinical and biochemical data are those required by prevailing guidelines for routine nephrology care, with a minimal dataset for all patients, and diagnosis-specific data for the diagnostic categories of primary and secondary glomerular disorders and adult dominant polycystic kidney disease, respectively. The dataset is supplemented by a biobank, containing serum, plasma, urine and DNA. The cohort will be longitudinally monitored, with yearly follow-up for clinical outcome. Future linking of the data to those from the national registries for renal replacement therapy is foreseen to follow the patients' lifeline throughout the different phases of renal disease and different treatment modalities. In the design of the data architecture, care was taken to ensure future exchangeability of data with other CKD cohorts by applying the data harmonization format of the Renal DataSHaPER, with a dataset based upon standardized indicator sets to facilitate collaboration with other CKD cohorts. Enrolment started in 2010, and over 2200 eligible patients have been enrolled in the different UMCs. Follow-up of enrolled patients has started, and enrolment will continue at a slower rate. The aggregation and standardization of clinical data and biosamples from large numbers of CKD patients will be a strategic resource not only for clinical and translational research, but also by its basis in routine clinical care for clinical governance and quality improvement projects