• Application Of Natural Channel Design Principles In Conversion Of A Multiple-Thread To Single-Thread Channel On An Alluvial Fan: Mccallum Creek, Alaska

      Roach, Christopher Hume; Carlson, Robert F. (2002)
      McCallum Creek crosses the Trans Alaska Pipeline in the Central Alaska Range near Paxson, Alaska. It was converted from a braided channel on an alluvial fan to a stable single thread channel at the pipeline crossing. Objectives included controlling the position of the channel at the pipeline and minimizing aufeis accumulations through the converted reach. A natural channel design methodology was used, which involves determining the dimension, pattern, and profile of a stable reference reach for the associated valley type and stream type and emulating those characteristics in the design reach. A failure mode analysis was conducted. Mitigative measures were identified for each potential failure mode. The channel was lowered to reduce surface energy loss and associated aufeis accumulations. Performance was good during the 2000 and 2001 seasons. Aufeis accumulations have not recurred. Lessons learned are presented from this and several similar projects constructed along TAPS in 2000 and 2001. <p>
    • Systems approach for applying remote video technology and the Internet to real time weather and runway condition reporting for aviation use: Case study at rural airports in interior Alaska

      Buckingham, James Miller; Perkins, Robert; Ra, Jang (2000)
      Aviation is critical to the infrastructure of Alaska. However, systems that provide runway and weather condition information about rural airstrips are not meeting the needs of the aviation community. Accordingly, aviation safety is compromised, efficiency of operations is reduced and service to clients is mediocre. Research was conducted to determine methods of improving the accuracy and reliability of runway and weather condition reporting Systems in Interior Alaska. A thorough background study of current reporting systems was conducted. A statistical study of aviation accidents in Interior Alaska was completed to document the premise that runway condition and weather reporting systems contribute to the problem. Current reporting systems were analyzed to isolate root causes of system degradation. An analysis of primary stakeholders associated with aviation reporting systems was completed. An hypothesis was formed which favored the use of remote video camera technology to provide near real-time weather information directly to end users A $114 K grant was obtained to conduct a test of the capabilities and benefits that would accrue from transmitting images of distant runway and sky conditions onto the Internet. For nine months, images of the sky and runway from three distant airstrips in Ruby, Kaltag and Anaktuvuk Pass, Alaska were transferred every thirty minutes to a publicly accessible website for use by the aviation community in assessing current conditions for preflight planning. Technical feasibility was confirmed. It was clearly determined that the system exceeded the expectations of the aviation community and provided greatly improved weather information to pilots. The aviation community in Interior Alaska has embraced the concept, used it operationally and declared it to be a critical enhancement to current systems. The project was an overwhelming success as confirmed by surveys, national and international media releases, and intense interest in the project by both private and governmental agencies. Aspects of the system are now patent pending. The research concluded that the remote video concept should be expanded throughout Alaska under the auspices of the Federal Aviation Administration (FAA) and/or the National Weather Service (NWS). Strong evidence was obtained to support potential expansion throughout the United States and internationally.
    • The Pluripotence Of Backcalculated Moduli

      Atkinson, Judith Ann; Raad, Lutfi (2002)
      The two main objectives of this research were first to investigate existing backcalculation techniques and the theories behind them for pluripotence (mathematical uniqueness of solution). Second to develop a backcalculation technique that addresses the pluripotence issue and attempts to overcome it. The first objective was accomplished by demonstrating that most existing backcalculation programs do have pluripotence issues of some sort. Each program was analyzed and an attempt was made to determine how pluripotence is evaded. To accomplish the second objective the computer program KISS was developed based on Composite Plate theory. The program was verified by analyzing the deflection equations used for Composite Plate theory and comparing them to some popular deflection equations used in backcalculation today. The Composite Plate theory equations were also validated using finite element analysis. Two types of sensitivity analysis were conducted. First the Composite Plate theory deflection equation was analyzed for sensitivity to various parameters. It was found that the deflections are most sensitive to layer thickness values and least sensitive to Poisson's ratio values. Secondly, the KISS program was analyzed for sensitivity. Plate size was investigated and it was determined that the plate size has a significant effect on backcalculation results. Variations in applied stress, seed values for D? and k and AC assumed strength (strong, average or weak) were also included in the sensitivity analysis. The KISS program was then compared with other popular backcalculation programs using data from the LTPP database. Three types of comparisons were made. First a Program-to-Program comparison was made in which the KISS program was compared to each of the other programs on a one-to-one basis. Secondly a Case-by-Case comparison was made in which the results from all programs were compared for each pavement system from the LTPP database. Thirdly, theoretical deflections from three different sources (Composite Plate theory, Elastic Layer theory, and finite element method) were generated for eight different theoretical pavement systems. In this method, the original moduli are known and were used as a basis for comparison.
    • Thermally enhanced bioventing of petroleum hydrocarbons in cold regions

      Filler, Dennis M.; Carlson, Robert F. (1997)
      Petroleum-based contamination of the environment has and will likely continue to be a problem as long as oil and natural gas supply much of the world energy demands. In cold regions, where vast quantities of these fuels are extracted and used, climate and frozen soils limit remedial efforts to a few technologies. Bioventing has shown promise as a viable method for the remediation of spilled petroleum-based fuels in cold regions. An in situ study of bioventing with soil warming was conducted at a Fairbanks, Alaska site. The main purpose of this research effort was to compare the effectiveness of thermal enhancement techniques applied to bioventing. Objectives included (1) developing a suitable thermal insulation system(s) that would provide year-round bioventing of petroleum contaminated soils, (2) modeling of the thermal regime below three treatment areas, (3) relating monitoring and testing data to thermally enhanced biodegradation, and (4) presenting the information in a way that is useful to engineers, biologists and environmental scientists. Active soil warming with electrical heat tape beneath polystyrene insulation and sand and gravel overburden raised subsurface soil temperatures from the ground surface to the water table by as much as 15$\sp\circ$F. The actively warmed test plot was successfully heated year-round, preventing soil freezing and enhancing microbial activity. Soil gas, microbiological, and geochemical sampling data evidenced correlation between increased bioactivity and soil warming. Passively treated soils evidenced some winter increase in temperatures, although some periodic soil freezing did occur. Overall, biodegradation within both passively treated and untreated contaminated test plots was noticeably slower than within the actively warmed plot. Thermally enhanced bioventing successfully remediated hydrocarbon contamination in vadose zone soils at a subarctic site within two years. After oxygen, temperature appears to be the most important factor affecting microbial activity and biodegradation. Variable and low moisture contents did not seem detrimental to bioactivity.
    • Use of synthetic aperture radar in estimation of wave climate for coastal engineering design

      Blackstone, Jill Ellen (1995)
      Development of Alaska's maritime resources requires design of efficient, reliable, safe facilities by coastal engineers who have a thorough knowledge of site specific wave climate: wave height, length, period, direction, and storm duration. Unfortunately, lack of wave information and validated hindcast models along the Alaskan coast often results in costly overdesigned facilities or underdesigned coastal structures which have a high risk of performance failure. To expand the nearshore wave climate availability, use of spaceborne synthetic aperture radar (SAR) data to estimate wave parameters was evaluated. SAR data were examined in raw and filtered forms, and the extracted wave climate compared to field measured data at three sites. Based on this comparison, the applications and limitations of SAR estimated parameters were established and incorporation of the information into current design practice was addressed. SAR based spectra were dominated by low frequency spectral peaks, likely due to random noise associated with SAR images, as these peaks were not present in the field measured spectra. Due to discrepancies between SAR and measured spectra, wave height, and storm duration could not be determined. Although error ranged from 12.5% to over 100% for SAR estimated wave lengths, the fact that wave lengths, although inaccurate, could be determined from SAR is promising. SAR based wave direction compared favorably to theoretical propagation directions which affirms the potential of wave parameter extraction from SAR data. However, directional field data were not available for comparison. Due to the current errors associated with SAR based wave estimations, SAR estimated wave climate cannot be incorporated into coastal design practice at this time. Research results suggest SAR data still hold great potential for estimating wave parameters. Examination of SAR based wave climate in an extensively monitored, open ocean setting would be beneficial, and the influence of environmental factors on SAR imaging of waves warrants additional investigation. Furthermore, development of a tandem SAR platform with temporal resolution on the order of seconds would be useful for wave period estimation and interferometric wave height determination. After this background research has been accomplished, another evaluation of SAR based nearshore wave climate would be worthwhile.