ISCORD 2013: Planning for Sustainable Cold Regions

For bridge erection in the extremely cold climates, ice can sometimes be an ally. Ice has frequently been used as a platform to support heavy construction loads and is often the most economical method of bridge erection when suitable conditions prevail. The technique for building ice platforms is described. Topics covered include site assessment, bearing capacity theory of ice, and the inspection and maintenance of ice bridges. Examples of several steel bridges erected off the ice illustrate this method of construction.

The Anchorage Water and Wastewater Utility (AWWU) owns, operates and maintains existing gravity sewer mains under the normal lake level, along the north and south shorelines of Campbell Lake in Anchorage, Alaska. Access to the lake is through private property or limited utility easements. Accessing AWWU's wastewater collection system in Campbell Lake is limited to periods when the water level is lowered or in winter due to shoreline impacts. The lake was man-made in 1959 by developers of existing homesteads. Campbell Lake has year-round use - from boating, swimming, and fishing in the summer; to skiing, snowmobiling, and ice-fishing in the winter. The lake is also used for year-round flying of private aircraft located on the lake. Construction projects on the lake require approval from both agencies and the Campbell Lake Owners, Inc.

The snow roads at McMurdo Station are the primary transport corridors to move personnel and material from airfields servicing intra- and inter-continental air traffic. However, being made solely of snow and ice, they are particularly susceptible to deterioration during the warmest parts of the austral summer when above-freezing temperatures can occur for several days at a time. Poor snow conditions can seriously limit payloads for all types of vehicles, including airplanes. The construction and maintenance of the snow roads has been studied for the last several years to develop best practices to optimize road construction, maintenance and use. This included looking at new technologies to improve maintenance operations. The Keweenaw Research Center of Michigan Technological University, the Cold Regions Research and Engineering Laboratory (CRREL), and the National Science Foundation (NSF) have teamed to assess the feasibility of using new grooming and milling equipment to build snow pavements in Antarctica. The SnowPaver - a single unit consisting of leveling blades, a milling unit developed specifically for use on snow, and a vibratory compactor - was built and shipped to McMurdo in November 2010. The SnowPaver was used to build several snow pavement sections that were monitored and subjected to controlled trafficking during the austral summer of 2010-2011. Measurements included snow strength and tire rut depths. Even though the miller portion of the paver was initially underpowered, the SnowPaver sections held up reasonably well. The paver was also found to be useful for reworking and compacting old and slushy snow during the height of the warm season. This season (Oct 2012 to Feb 2013) we plan to upgrade the SnowPaver hydraulics and power to achieve full leveling, milling and compaction all with one pass of the implement.

In Alaska, a high percentage of projects are 'off the road system' and are considered remote locations. This aspect adds to the challenge of getting equipment and personnel to the job site. An additional challenge can be the weather; seasonal variations can work for or against the project in many ways. Preparation for a remote project is complex. In order to have a successful project, a great deal of planning is necessary and consultation with a person familiar with the area or experience working in remote areas is critical. Being able to respond to changes that can and do occur in the field, and anticipating scenarios that could occur and how to respond to those scenarios are crucial to a smooth running field program. Movement to and from the project for personnel, equipment, and samples may involve aircraft, boat, or off-road vehicles. Many projects involve setting up a temporary or long-term "camp" for the personnel which requires lodging, food, sanitation, transportation, and preparation for emergencies. Front end attention to even the smallest of logistical and project support detail can and will reduce the frustration of the Project Manager, personnel working on the project, and ultimately for the client. Reliance on last minute preparations can have immediate and long-term negative repercussions and be costly to the project. A successful field project doesn't happen automatically. It is important for all managers and key players, and our clients, to realize that a project that seems to run flawlessly is most likely one in which a great deal of thought has gone into the entire program planning process. Anticipating what can go wrong before ever leaving the office will allow for readily available at-hand information if things do go wrong once the project is underway. Having a back-up plan or several contingency plans ready to enact can often times save the project budget, the schedule and make the best use of all resources; both personnel and equipment. Pre-planning is especially important when you are dealing with a remote project. Your particular definition of remote may vary depending on where your offices are located, or where you commonly execute your field projects. Remote may be a job site that requires renting a 4 wheel drive vehicle to complete a project in Death Valley on dirt roads. Or remote may be one that requires flying to another state. In Alaska remote can take on a new, expanded, and to some, an awesome, unimaginable definition.

A field testing program was developed and performed for two years on Alaska's arctic North Slope. The objective of this testing program was to characterize the long- and short-term adfreeze performance of vibratory-driven piles installed into native frozen soils. A new direct-driven installation method has been developed using a vibratory ram driven from a mast-mounted rack. The energy of the vibrating pile thaws the frozen ground surrounding the pile as it is driven to its design elevation. The installation is efficient and provides economic advantages over traditional installation methods. Twelve 12.75-inch-diameter steel pipe piles were installed in permafrost in the Alaskan arctic; eight piles were installed in ice-rich, sandy silt and four piles were installed in a frozen gravel soil. Piles were loaded in tension for six different durations ranging from five days to six months at loads varying from 35 kips to 145 kips. At the completion of long-term testing, the test piles were unloaded, rested, and then loaded to failure to characterize the adfreeze short-term strength. Data was collected continuously using electronic linear variable displacement transducers (LVDTs), load transducers, and thermistors. Data was analyzed to develop normalized long-term pile velocities and short-term strength as a function of loading stress and adfreeze temperature. Experimental results were statistically compared to current theoretical and empirical performance. It was found that vibratory-driven piles perform comparatively to traditional drill-and-slurry pile installations.

The British Antarctic Survey has operated and maintained a facility for science on the Brunt Ice Shelf in Antarctica since the International Geophysical Year in 1956-7. Located at the southern end of the Weddell Sea, Halley provides a facility for atmospheric sciences and glaciological and meteorological studies. The floating ice shelf on which the station is built moves towards the sea at approximately 400 metres per year and the mean surface level rises each year by 1.5 metres. The Halley I to Halley IV structures were abandoned after they became unsupportable and sank below the surface. It became necessary to replace Halley V as the risk of the ice shelf breaking away became apparent. Halley VI is now occupied and the science systems are fully operational. The station will be finally completed in February 2013. With hydraulically operated legs, it is possible to raise the structure above the ice surface. The modules from which the station is constructed can be moved to overcome any risks that may be posed by the loss of the edge of the ice shelf.

The climate of the Arctic has warmed significantly in the last 30 years, adversely impacting the subsistence way of life. In the Arctic region, climate change effects are not limited to just air and ground temperature, but also include other parameters such as precipitation, snow cover, sea ice concentration, vegetation, and the cumulative mass balance of glaciers. Much of the ongoing research on climate change impact in Alaska is at a regional scale and is interpolated to the local scale. Regional and global climate change models only provide generalized information and marginally distinguish between different systems or site-specific impacts. As part of this study, qualitative climate change assessments of three representative villages (located on different systems, for e.g.: coastal, river, groundwater-wells; and ponds or lakes) are being performed. Observation and findings on climate change impacts on each of these communities are presented.

High-level expertise is increasingly important for the development in cold region countries. Doctoral degree is a clear advantage in international cooperation in business, consultancy, education and sciences. In Finland, nationwide systematic doctoral education was introduced in 1995 in a form of a graduate school system. The system aims to ensure high quality and systematic training for doctoral students with entry into working life within four years. By 2012, the expanded system consisted of 1600 funded, 4-year, student positions in 112 graduate schools. Most of these graduate schools are based on nationwide or local cooperation between universities and research institutes. The doctoral training system in its present form will be terminated by the end of 2015, and each university will establish its own graduate school systems. This paper introduces the systematic Finnish doctoral education system and examines its future.

The management of Greenlandic municipal solid waste incineration (MSWI) fly ash could be improved. Presently, the fly ash is disposed of in Norway as the fly ash is classified as hazardous waste. Fly ash contains high amounts of leachable heavy metals, but also resources that could be beneficial for reuse. In electrodialytic remediation, a direct current is applied to a contaminated particulate material to remove heavy metals from the material. In this study, electrodialytic remediation was applied to a Greenlandic MSWI fly ash from a small waste incinerator in Ilulissat. The fly ash was characterized before and after the electrodialytic remediation experiments for heavy metals content, amount of soluble heavy metals and pH. Before the electrodialytic experiments, the water solubility of Ba, Cr and Pb was high from the alkaline fly ash. Six electrodialytic remediation experiments were made, where the fly ash was suspended in distilled water in different liquid to solid (L/S) ratios. Remediation times of 7 and 14 days were tested and the current strength was 50 mA in all experiments. The highest removal was seen when an acidic pH in the fly ash suspension was obtained. In an experiment lasting 14 days with L/S 10, up to 60 % Cd, 45 % Zn, 20 % Ni and Ba were removed. Regardless of the remediation time and L/S ratio, the fraction of soluble Ba, Cr and Pb decreased due to the electrodialytic remediation. The electrodialytic remediation method showed potential as a treatment method for the Greenlandic fly ash.

Snow scavenges organic contaminants from the atmosphere and has been shown to retain a variety of contaminants. Concentrated release of organic contaminants during onset of melting due to interstitial melting suggests an immediate transfer of organic contaminants from snow pack to surface water via storm drainages. Urban environments in a climate with extended periods of snow, such as Alaska, Maine, Minnesota, Canada, and Northern Europe, therefore may experience organic contamination of surface water during snowmelt. This study presents first results on a multidimensional assessment of concentration and changes of organic contaminants, specifically 1H-benzotriazole (BT) and its methylated forms, 4- and 5-methyl 1H-benzotriazole (tolyltriazole TT), during snowmelt in an urban creek that passes through Anchorage, Alaska and discharges into Cook Inlet and in two snow dump sites (snow and melt water). Results indicate concentrations up to 310 ng L^-1 BT and 4490 ng L^-1 TT during snowmelt. The timing of peak agrees with increasing levels of Na⁺ and Cl^- and anthropogenic derived organic material based on fluorescence spectrometry. The concentrations of BT and TT are comparable to those in streams passing through larger industrial cities in Europe, and TT peak concentrations are even higher than those previously determined in streams in Europe and the U.S. In June, after spring melt, while overall DOC increases, concentrations of BT and TT return to levels close to detection limits (e.g. background concentrations) and fluorescence spectrometry indicate that organic carbon becomes more terrestrially derived.

This paper presents the recent research conducted at the Arctic Technology Centre, where different solutions for remediation of excavated oil contaminated soil in Greenlandic towns were tested. In the first work, soil polluted by light oil was treated with two different nutrient sources (substrate and N:P:K), stabilizer (crab shells) and heating (20°C). In this work, a clear reduction in hydrocarbon content was observed during the treatment period of 730 days. No significant difference in degradation was observed between the two different nutrient sources, and no effect of crab shells was observed. The degradation proceeded further at the elevated temperature and even more when heat and nutrients were combined. In the second work, a nutrient-rich soil, highly polluted by weathered heavy oil, was aerated by insertion of air-channels and heated to 20°C. Between 19 % and 34 % of the oil pollution was removed during the 81 days of the experiment. Analysis by Gas Chromatography-Flame Ionization Detector showed that the lighter fractions were removed, while the heavy oils remained. In the third experiment, the oil contaminated soil is subjected to sequential treatment including adding of surplus heat from the local waste incineration plant. The results showed the highest reduction of the oil-contamination for the set-up with a combination of heat and sphagnum.

Migration of aqueous phase contaminants from underground tanks, nuclear waste sites, and in situ waste treatment areas into the groundwater is of concern at many locations. There is a wide range of technologies to remediate contaminated sites. Some examples are: constructed wetlands, air sparging, bioremediation, and permeable reactive barriers. One technology that has not been widely used is frozen soil barriers. The barrier provides containment of liquid contaminants in order to prevent their migration to adjacent areas. This is a promising method that is environmentally friendly and offers a safe alternative to other methods. Frozen barriers can be formed using a series of subsurface freezing pipes or probes. The installation of frozen barriers disturbs the existing ground minimally and only existing in-situ material is used. An artificial frozen barrier using hybrid thermosyphons was installed in Fairbanks, Alaska using six thermosyphons placed at a distance of 1.5 m. The system ran actively for about 60 days and operated in a passive phase during the winter months. A detailed description of the thermal performance of the barrier in Fairbanks from March through September will be presented.

This paper details the geotechnical and cold regions engineering associated with replacing Alaska Railroad Corporation's (ARRC's) Goldstream Valley Bridge, including: discussion of past performance of the former bridge, subsurface investigations, and foundation design for supporting the new bridge on driven steel piles supplemented with passive refrigeration. The aging former bridge was performing poorly (although still under safe operation) due to degradation of the relatively warm permafrost, stream bank erosion and minor migration of the stream channel with time. ARRC proactively replaced the bridge with a new, longer span that placed the new abutments beyond the ends of the former bridge, and installed a new pier near the apex of the thaw bulb (which, theoretically, is relatively symmetric with any potential continued lateral soil migration). The steel pile foundations for the new bridge are being passively cooled using thermosyphons in order to limit further degradation of the permafrost around the support soils and aggrade frozen soils immediately surrounding the piles. The bridge was reconstructed in 2009/2010 and instrumentation has been installed to monitor thermal performance.

A permafrost-related geohazard is approaching the Dalton Highway near MP219. Analysis of historic, remotely-sensed imagery indicated that this feature, termed a frozen debris lobe (FDL), was moving at an average rate of 0.4 in. per day between 1955 and 2008. More recent measurements indicate an increased rate of movement. As this frozen debris lobe (FDL-A) is less than 200 ft from the Dalton Highway, it is necessary to determine its current rate of movement, the nature of its movement, and its internal structure. We conducted field investigations in 2012 to determine the thickness and stratigraphy of FDL-A, and to install instruments to measure temperature, water pressure, and slope movement. Temperature measurements indicate that, although frozen, FDL-A is 2°F warmer than the surrounding permafrost. Results from the field work indicate that FDL-A is fairly homogeneous, consisting of silty sand with gravel, and is 86.5-ft thick where drilled, overlying white mica schist bedrock. It is moving mostly along a shear zone between 66 ft and 74 ft below the ground surface at an average rate of 1.0 in. per day. As this rate was measured only during the fall season, however, it does not reflect any slowing of the lobe that may occur through the winter months. As these results are preliminary, future work will entail recording the positions of surface markers on FDL-A, conducting geophysical surveys of the feature, and modeling FDL-A to determine the geometry of the shear surface and residual strength in the shear zone, and to identify possible mitigation strategies.

The electrical resistivity of soil is affected by various factors, such as the electrical resistivity of pore fluids, the porosity, the constituent of soil particles, the saturation, the orientation and shape of soil particles, and the pore structure. The purpose of this study is to determine the changes in the electrical resistivity of sand-silt mixtures during freeze-thaw cycles. To measure the electrical resistance over freeze-thaw cycles, a nylon cell was designed and an electrode was attached to each of the four side walls of the cell. Two specimens, with different degrees of saturation (40% and 60%), were prepared using sand-silt mixtures. The measured electrical resistances were then transformed into electrical resistivities. The results show that, in both specimens, the electrical resistance increases during the repeated cycles, and hysteresis behavior appears immediately after the beginning of thawing. In addition, the electrical resistivities of both samples are less during thawing than during freezing from 0°C to -3°C. While the electrical resistivity increases rapidly at 0°C during freezing, the electrical resistivity at 0°C decreases relatively gradually during thawing. For the specimens with a saturation of 40%, the electrical resistivity during thawing was greater than the electrical resistivity during freezing at ordinary temperatures. This study demonstrates that electrical resistivity surveys may be useful for analyzing the structure and behavior of soils during freezing-thawing cycles.

The characteristics of ground motions for different seismogenic zones of the world due to strong local earthquakes revealed that the amplification of the spectral acceleration (SA) is one of the important parameters to be estimated for the assessment of seismic hazards. Accordingly, the spatial variation of spectral acceleration been estimated for the Anchorage basin using the data recorded from 38 free-field station sites in the area. These stations are distributed throughout the basin to obtain seismic coverage from various lithological units. One of the stations is located on the metamorphic terrain of Chugach Mts. in the eastern part of the basin and has been considered as the reference rock site station for site response computation. Each station is equipped with Kinemetrics Altus K2 accelerographs and the recorded data are sampled at the rate of 200 Hz. The recorded events are having magnitude (M_L) in the range of 2.6 to 5.5 with focal depth varying from 10 to 150 km and providing a good azimuthal coverage with respect to the center of the seismic network. The 5% damped SA of the recorded data from each site was determined for the period range of 0.04 to 15 sec. Amplification of the SA values was computed using standard spectral ratio (SSR) method assuming the unit site response at the reference station site for the above period range of interest. The estimated amplifications values at each site were band-averaged with the central period at 0.2 sec and 1.0 sec. The band-averaged site amplification values were correlated with the 30-m shear wave velocity values (β₃₀) available from some station sites. A strong correlation has been observed to exist between the long period site amplification and β₃₀ values. However, for short periods, SR is almost constant with the β₃₀ values. The paper will discuss the presence of various near-surface lithological units on the observed spatial variation of amplification of the SA values. Two spectral acceleration-based site amplification maps at 0.2 sec and 1.0 seconds have been prepared for the area to capture the spatial variation of the characteristic ground motions that will be directly useful for the earthquake engineering analysis in future.

Various models have been proposed for frost heave estimation. However, a practical evaluation method for multi-dimensional deformation has not yet been established. This study aims to discuss the possibility of expanding an existing evaluation method into three dimensions based on previous experience on simulating interactive behavior between an underground structure and frost heave. Takashi's equation was adopted among several frost heave models considered. This model has been used to estimate one-dimensional frost heave according to the Japanese Geotechnical Standard. However, it is applicable only for one-dimensional frost heave. The authors developed a new apparatus to measure three-dimensional frost heave to apply Takashi's equation to multi-dimensional heave. A modified equation was proposed based on the experimental results. Considering the effect of anisotropic properties on frost heave, this proposal was adopted for a simulation program by coupling the heat transfer calculation and mechanical equilibrium analysis in a finite element method (FEM) model. The fundamental simulation results are presented in this paper as an example to confirm the proposed model's applicability.

Frozen backfill for underground mining operations in permafrost must be delivered in such a state so as to not thermally impose on the host rock surrounding the filled stope. The placement process, material strength demand, and freezing time delay are the key parameters that control the applicability of the method. The thermal properties, initial temperatures, and mix ratio of the constituent materials (i.e., waste and water) can be used in a simple thermodynamic equilibrium model to predict the final temperature of the backfill upon placement. The introduced frozen rock and tailings must be at subfreezing temperatures and get fully wetted during the spraying so the surfaces of the particles adhere to one another and the tailings become a solid interspersed between the rock particles, enhancing the solidification of the poured backfill. Results, based on a two-year research program, provided a mix design and a delivery process for open stoping operations in permafrost regions. The testing evaluated the sensitivity of parameters, including: the amount and temperature of water added in the mix, the rockfill/tailings ratio and the temperature of solid constituents. This paper presents an innovative, patented technology for the mixing process of the fill material without the addition of cementitious agents. The distribution of the materials and the placement process are instrumental in achieving the mass properties required for the stabilization needs of open stoping applications.

The history of railway construction in permafrost zones in Russia, USA, Canada and China has extended more than 100 years. Nonetheless, no one has ever been able to build a railway track not subject to deformation caused by subsidence resulting from ice-rich subgrade soils thawing. This paper presents data on the roadbed state in the Zabaikalye and the Qinghai-Tibetan Railways as well as the Baikal-Amur Mainline. It also covers the possibility of roadbed stability maintenance using methods based on the reduction of the mean annual ground temperature and roadbed preservation in a permafrost state by means of the natural cooling and heating factors ratio regulation resulting in a reduction of the heat generation in the roadbed and the adjoining area accompanied by an increase of heat consumption. The research results on the Qinghai-Tibetan Railway and the East-Siberian Railway are given.

What is unique about geotechnical engineering in cold regions? Principles of soil mechanics for temperate climates have been largely well-understood and practiced for decades. However, these are based on soil temperatures above freezing. In cold regions, heat flow becomes important in relation to freezing and thawing (seasonal frost), but also in relation to permafrost and its resistance to thawing and consequences of thawing. Soil moisture experiences a change of phase and this can cause a dramatic change in physical properties of the soil. In addition, porewater migrates in certain soils during freezing and this can cause dramatic heaving, well in excess of that which would be caused by phase change alone. Based on an illustrated "white paper" recently prepared for colleagues practicing geotechnical engineering in temperate areas, the authors summarize these fundamental phenomena, providing examples of practical design approaches which have been successfully used for building foundations and for roads in seasonal frost and permafrost areas. The paper concludes with a list of relevant references for readers interested in geotechnical design criteria and more-specialized cold regions engineering topics.

Frozen soils, especially seasonally frozen soils, have great impact on the seismic performance of bridge pile foundations. To account for its impact on pile foundations in the seismic analysis of bridge foundations, it is necessary to evaluate the mechanical properties of naturally frozen soil samples at a strain rate that is compatible to that induced in the frozen soil during a seismic event. This paper presents the mechanical properties obtained from testing of naturally frozen silty soils in Alaska. Uniaxial compression tests were conducted on naturally frozen soils, including both seasonally frozen soils and permafrost obtained from Alaska. All tests were conducted at a constant deformation rate corresponding to a strain rate of 0.1%/s. Both horizontal and vertical specimens are tested under various temperatures below the freezing point. Testing results, including soil characteristics and mechanical properties such as stress-strain curves, compressive strength, modulus of elasticity, and strains corresponding to the peak compressive strength and 50% of peak strength, are presented. The impact of temperature and dry density on the mechanical properties is discussed.

For designing infrastructure foundations in cold regions, it is essential to evaluate the mechanical properties and characteristics of naturally frozen soils obtained from the field. However, sampling frozen soils is a difficult task, especially when looking for minimally disturbed, naturally frozen soil samples. The less disturbed the samples are, the more reliably one can evaluate the mechanical properties of the frozen soils at its in situ condition. This paper describes the detailed processes used to extract and machine naturally frozen soil samples for mechanical property testing. The extraction process involves a chainsaw with a carbide chain to cut a square into the ground of the desired size, and the isolated block is snapped from the ground using a wedge. The machining process involves cutting the block sample into octagons. During this process, particular attention is paid to the orientation of soil fabric. Once an octagon is made, a lathe is used with a special holding bit to avoid disturbing the octagon ends. Carbide cutting tools are needed as standard cutters dull very quickly and begin heat-affecting the soil. The rate of lathing is carefully controlled to minimize the heat disturbance and roughness of the cylinder surface. A four-jaw chuck is used to face both sides of the specimen with the lathe to ensure the two faces are parallel. This machining process is believed to minimize the thermal and mechanical disturbances to the specimen. The testing equipment and sensors used to measure the stress-strain behavior are described. Testing data obtained from two sets of examples with different orientation angles are presented.

One of the arduous tasks in cold regional studies is estimating soil hydraulic properties, such as soil freezing characteristics and hydraulic conductivity, which are important when studying transport process in frozen soils. Costly data collection methods and existing isothermal models are limitations in understanding soil water dynamics in frozen soils. Pedotransfer functions have become a hot topic in the earth- and environmental-related sciences to predict soil physical and chemical properties easily, routinely, or cheaply for a specific non-frozen geographical region. Based on similarity between wetting and freezing processes in soil, we presented a new approach to derive soil freezing characteristics from soil water characteristics of non-frozen soils using existing pedotransfer functions. We considered a conventional soil water characteristic model and existing pedotransfer functions for determining the relationships; unfrozen water content vs. subzero temperature, and hydraulic conductivity vs. subzero temperature using Clapeyron equation. The proposed approach successfully predicted unfrozen water content and hydraulic conductivity for different soils when compared with those reported in the literature. Furthermore, effect of soil bulk density (porosity) on unfrozen water content and hydraulic conductivity at different subzero temperatures was discussed for range of soils.

In snowy, cold regions, embankments constructed in winter may cause settlement and collapse of slopes in the thawing season in early spring. One of the reasons may be unavoidable suspension of the work due to work schedules while constructing an embankment during a cold winter. Accordingly, assuming such construction, a test construction was conducted in the winter season. For the constructed embankment, its inside temperatures and strength were measured. Also, after the embankment melted, it was cut open and the density and water content were measured. As a result, it was found that: (1) even in a 30-cm-high embankment, frost and moisture movement occur; (2) a frozen embankment is strong, but a non-frozen one is not strong; (3) depending on the embankment construction method, layered frost remains and the number of layers increases with the increase of construction days; and( 4) when the embankment freezes, the density and water content decrease.

An elasto-plastic constitutive model for freezing and thawing soils is developed to capture the deformation behavior and strength evolution of the soil subjected to mechanical loading as well as temperature changes. The model is based on the critical state framework, with the yield condition as in the modified Cam clay model. It uses the ice ratio as a scalar parameter to describe the evolution of the yield condition due to freezing and thawing. The model has been calibrated and implemented in the finite element system, ABAQUS, to solve boundary value problems. Freezing and thawing of soils in proximity of a retaining wall is simulated using the model.

The National Geodetic Survey (NGS) traces its roots back to the first scientific agency of the United States, the Survey of the Coast. In 1807, Congress endorsed the request of President Thomas Jefferson to establish a Federal agency to survey the coasts of the United States in support of growth and development of our young country. While the Survey's name has changed over the years, the need for accurate surveying remains the same. Today's NGS provides the United States and its territories with the most accurate geodetic framework for all types of geodetic control, indispensable to surveying, engineering, and mapping activities. Technology and methodology have evolved over the years, but our mission "to define, maintain, and provide access to the National Spatial Reference System to meet our nation's economic, social, and environmental needs" remains.

Geotechnical and geological data relating to the North Slope of Alaska exists in a variety of sources ranging from scanned historical geological maps and reports to site-specific geotechnical investigations, typically stored in separate and sometimes proprietary reports. Obtaining historical geotechnical and geological information is difficult due to the lack of availability of the historical reports. The obstacles in accessing historical information can lead to redundant information being gathered such as expensive drilling programs in areas which have been previously drilled. To capture and provide better access to historical geotechnical and geological data, as well as to prevent drilling unnecessary boreholes on Alaska's North Slope, Golder Associates has compiled historical geotechnical and surficial and near surface geological data and placed it in a GIS database. The compiled database includes publicly available geologic mapping, historical borehole data, and field sites. In addition, a borehole reporting system tool was developed for the GIS system which includes metadata about individual boreholes and actual borehole logs as available. Finally, to incorporate future geotechnical borehole data, a custom publishing tool was developed for updating and maintaining the GIS database.

Gravity for the Redefinition of the American Vertical Datum (GRAV-D) is a project by NOAA's National Geodetic Survey to replace the current U.S. vertical datum with a gravity-based datum by 2022. This will be accomplished by using airborne and other gravity data to develop a geoid height model suitable for determining GNSS-derived orthometric heights. While GRAV-D will collect data over all states and territories of the United States, a significant portion has already been collected over Alaska. Some regions are still being processed, but data have been released in four sections of the Anchorage-Kenai and Fairbanks regions, where RMS crossover errors are between 1.3 and 2.7 mGals. Aerogravity is critical, especially in coastal areas such as that near Anchorage, because it bridges the gaps between offshore ship track gravity observations, terrestrial data, and satellite data. Its uniform 10-km track spacing provides a consistent coverage that resolves features between 40 and 500 km scales. It will serve to detect and mitigate errors in surface gravity data and unify the gravity field in support of the desired cm-level accuracy for vertical heights.

The United States and Canada plan to adopt geoid height models as the basis for their respective national vertical datums. Canada is moving forward in 2013 to do this, but the United States will await the completion of the Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project in 2022. While the entirety of the United States and most territories are in the GRAV-D plan, much of Alaska was frontloaded with the bulk of collections already complete as of 2013. This affords the opportunity to develop a refined gravimetric geoid height model based on the improved gravity field to test the impact of the new aerogravity data. Comparisons demonstrate that some of the existing surface data have biases of up to 7 mGals with spatial extents of 20-50 km. These errors contribute directly to an error in the geoid at dm-level even with additional satellite gravity mission data incorporated. Hence, the GRAV-D project represents a necessary middle step to ensure a cm-level accurate geoid height model to serve as a future U.S. vertical datum and possibly a common model for the entirety of North America and as a component of a World Height System.

Since 2002, the National Geodetic Survey (NGS) has made available to the general engineering and surveying community a web-based GPS processing software named the Online Positioning User Service (OPUS). The popularity of this free service has steadily increased over time and Alaskan GPS users were no exception in quickly adopting this simple-to-use positioning tool. This article discusses recent CORS improvements performed in Alaska and the importance of keeping track of changing NGS published coordinates which is crucial to all GPS surveys in a region with crustal dynamics as active as Alaska. The status of the Continuously Operating Reference Stations (CORS) network in Alaska will also be reviewed. More CORS sites in the state will undoubtedly help the use of other newly developed versions of OPUS, such as OPUS-RS, OPUS-Net and OPUS-Projects. Each one of these flavors contains its own specific applications; therefore, they expand the OPUS arsenal with a variety of alternatives making the culmination of surveying engineering and mapping projects more user friendly.

Crustal motion in the western United States and Alaska, due primarily to tectonic forces, causes positional coordinates of points on the Earth's surface to change over time. As a result, accurate surveying in these areas requires an equally accurate description of this deformation to allow survey measurements conducted at different times to be corrected for such movement. NOAA's National Geodetic Survey (NGS) has developed the horizontal time-dependent positioning (HTDP) software that enables its users to make these corrections. HTDP may also be used to transform coordinates measured at one time to corresponding coordinates that would be measured at some other time. To accomplish these tasks, HTDP contains numerical models describing interseismic horizontal crustal velocities. HTDP also contains models describing the displacements associated with 30 major earthquakes, including two in Alaska. NGS updates the HTDP software periodically to incorporate newer models. Over the last few years, NGS has made substantial advances in developing models to allow coordinates and survey measurements in Alaska to be corrected for crustal motion. This includes models describing Alaska's horizontal velocity field, and models for both the coseismic and postseismic displacements associated with the 2002 Denali Earthquake. The Denali postseismic model is the first such model included in a version of HTDP.

Ice roads over the Arctic tundra and sea ice have been constructed for decades and create the opportunity to explore remote natural resources and continue to prove the industry can find, and safely produce, cold region resources while protecting the environment. During the winter of 2011-12, two oil companies, Pioneer Natural Resources Alaska, Inc. (Pioneer) and Repsol E&P USA Inc. (Repsol), managed separate exploration programs and shared an ice road alignment within the Arctic coastal region of Alaska's North Slope. This paper presents the ice engineering and construction components incorporated to help ensure the ice roads facilitated the drilling programs. A total of six remote exploratory well sites were planned for both programs, which required constructing: eight ice pads totaling 40 acres for drill sites and camps; 23 miles of tundra ice road; 31 miles of sea ice road including a floating ice bridge; and a 4.5-acre drill site on an offshore ice island. The sea ice road was planned to be grounded, however dynamic offshore conditions prevented a 350-foot long section to ground and required a 13-foot thick ice bridge to safely distribute the design load of 2.2 million pound drill module. The offshore ice island was designed to withstand ice pack forces of 200 psi and 2-foot tidal surges. The finished elevation of 11.5 feet was completed in 14 days and required about 12.8 million gallons of water and ice chip aggregate. At the end of the season, April 30, 2012, all personnel, equipment and materials were removed, roads and pads were cleaned, and the season finished leaving little trace of oil exploration.

The process of selecting a field development concept following a discovery involves a complex iterative interaction between its key elements of subsurface, drilling and completions, surface facilities, and commercial and regulatory considerations. The objective is to understand how different risks and uncertainties impact each scenario, leading to the final selection of the single concept that best balances the key elements and extracts maximum value for all stakeholders. A recommended procedure for Arctic concept selection has been developed using a building-block approach matched with a practical and systematic method for understanding the key drivers and uncertainties in a project. In order to complete this type of analysis, experienced professionals are equipped with a toolkit and set of processes that allow a disciplined approach to only doing work that is focused on each decision that has to be made. This then leads to the development of a decision-based plan to extract the maximum value from any opportunity. Also discussed are some of the common traps that can befall a concept selection study such as: solving the wrong problem due to an inadequate project frame; utilizing incorrect, invalid or out of date data; having inadequate systems and tools in place to maintain focus and alignment; an inability to articulate key insights; a lack of team integration; and, finally, the dangers of an activity-based workscope instead of a decision-based one.

Subsea pipelines located in ice environments need to be protected from potential ice gouging (also known as ice scouring) created when a moving ice keel interacts with the seabed. The integrity and operability of the pipeline can be affected by direct contact between the ice keel and the pipeline, or from loading imposed on the pipeline through soil deformation caused by ice gouging. The typical method considered for protecting against the risk of damage caused by ice gouging is through pipeline burial. Conventional methods of pipeline burial use equipment such as ploughs, mechanical trenchers, and jetters, the majority of which have been designed to accomplish a maximum of 2-3m of pipeline burial. Dredges can be used, but they have water depth limitations and limited productivity. Land-based equipment has been used for shore crossings, but is limited to shallow water depths where temporary construction berms can be used as a working platform. The capabilities of existing technologies are based on current industry practice developed for pipeline burial in ice free environments. Pipeline burial requirements have generally been for improved hydrodynamic stability, mechanical protection (e.g. from anchors), controlling pipeline movements (e.g. expansion and buckling) and/or for flow assurance purposes (reducing heat loss). A 2-3m burial depth has been generally adequate to satisfy these conventional requirements. As developments are proposed for areas that experience relatively deep ice gouging (up to 5m), burial depth requirements will exceed the capabilities of current pipeline burial technologies. New technologies capable of working in deeper water, achieving greater burial depths, achieving reasonable trenching advance rates, operating in harsh environments, and trenching through variable and difficult seabed soils will be required. This paper highlights the issues and challenges surrounding pipeline trenching and burial in ice gouge environments. Current state-of-practice is discussed along with the technology gaps that need to be addressed to prepare for future offshore developments in ice-covered waters where there is the potential for seabed ice gouging.

Japan is located between the latitudes of 20 and 45 degrees north, and its northern part is characterized by amounts of snowfall rarely seen at such latitudes in other parts of the world. In the 1990's, a ban was placed on the use of studded tires in Japan to prevent harmful environmental impacts from the dust they produced. However, as a result, the incidence of winter accidents on slippery roads has significantly increased, and measures to combat icy road surfaces have become a major part of winter road maintenance work. Salting and gritting are common practices, and where to apply these treatments is a key factor for refining them. In order to support prompt and accurate decision making, the authors have measured road surface friction using a continuous friction tester (CFT) which can perform constant measurement. In addition to the monitoring of road surface conditions (i.e., slipperiness) along routes, continuous friction measurement is also useful for identifying road sections and conditions that require special attention. However, variations in road surface conditions depend on a number of factors, such as weather, road surface temperatures, road structures, and topographical characteristics. Accordingly, there is a need to accumulate road surface friction data and related information for different weather conditions in order to support the establishment of diagnostic techniques for clarifying patterns of spatial variations in road surface friction and identifying where and when slippery conditions are likely to arise. In collaboration with road authorities, CFT data on road surface friction/temperatures and information on road structures were accumulated to clarify basic skidding characteristics and identify hazardous locations/conditions on the case study route. Reproducibility of road surface friction distribution was found under several weather conditions and certain friction tendencies at the tunnel entrance were also identified.

As the slipperiness of winter road surfaces significantly influences vehicle motion, quantitative indexes such as the roadway friction are used for road management in some Western countries. Against this background, practical devices that can be used to continuously evaluate friction have recently been developed based on advances in technology to support quantitative assessment of winter road surface conditions, and have been introduced in a number of countries. However, as related measuring devices, principles, methods and other details vary by country, international comparison of test results and winter road services is difficult. In this study, the authors compared winter road surface management criteria, measurement methods and instances of utilization in other countries to determine suitable winter road management and service standards for Japan's regional characteristics. This paper presents the findings of the study and discusses future prospects.

The frost penetration depth of paved road in Korea is usually estimated from the freezing index that made temperature data analysis of 30 years and decided the thickness of anti-frost layer. The field monitoring region was divided into three regions by freezing index 550~650°C·day, 450~550°C·day, and 350~450°C·day. Each region has three-section of road pavement such as cutting area, boundary area of cutting and banking, and lower area of banking. The field monitoring system was established both in the section of anti-frost layer and in the section without anti-frost layer. The analysis was conducted for determination of frost penetration depth within the paved road by the field monitoring data. The temperature of subgrade without anti-frost layer shows below zero in centigrade for the region of freezing index 550~650°C·day, up and down around zero degree in subgrade for the region of freezing index 450~550°C·day, and no place existed below zero degrees in subgrade for the region of freezing index 350~450°C·day. With comparison of field frost penetration depth for the cross-sections of paved road, the cutting area shows the greatest frost penetration depth, less influence of frost penetration depth for the boundary area of cutting and banking, and the least influenced for the lower area of banking. After all, all the field collected data will be utilized as an important parameters for the design of paved road in Korea.

Many low-volume roads in the United States and other countries are located in seasonal frost areas where freeze-thaw processes result in costly damage to the roadways. In order to reduce damage, road management agencies apply Spring Load Restrictions (SLRs) which restrict the allowable load on the road during the critical time interval when the pavement is most vulnerable to damage. This paper discusses several quantitative approaches proposed for use in posting SLRs: (1) a method proposed by Mahoney et al. (1986); (2) the Berg/USFS method (Berg et al., 2006; Kestler et al., 2007); (3) recommendations proposed by the Minnesota Department of Transportation (Mn DOT, 2009) and (4) recommendations developed by the Manitoba Department of Infrastructure and Transportation (MIT) and FPInnovations (Bradley et al., 2012). All of these approaches recommend SLR starting dates based upon a cumulative thawing index threshold. In some cases, thresholds for SLR removal are also recommended. The four methods/models were evaluated by comparing the trigger dates determined from the models with measured frost-thaw profiles and with falling weight deflectometer (FWD) data obtained at eight field test sites in NH. Overall, this research suggests that both the Berg/USFS method and the Mn DOT method yield reasonable estimates for SLR application dates in northern NH. For removing the SLRs, this study suggests that adoption of a CTI threshold similar to that suggested by Bradley et al. (2012), with an eight-week maximum SLR duration, may be appropriate. However, due to limitations in the FWD data obtained to date, additional mechanistic analysis regarding appropriate thresholds for SLR removal is recommended.

To ensure safe driving, it is very important for drivers to appropriately perceive road alignment, pavement markings, various road accessories and road surface conditions. However, road surface conditions change with the weather, and in cold, snowy regions can vary widely from dry to wet to compacted snow during the winter months. Compacted-snow-covered roads pose a range of problems, including preventing drivers from seeing pavement markings and making roads slippery. As the northern part of Japan is characterized by the harsh weather conditions commonly seen in cold, snowy regions, there is increasing interest in the evaluation of drivability and safety for modern roundabouts in various weather and road surface environments. The authors installed a small single-lane roundabout for experimental purposes on the Tomakomai Test Track in Hokkaido, Japan, in autumn 2009 and winter 2010 to enable related driving tests. A total of 16 subjects participated in these tests and drove test vehicles, some of which were equipped with a driving-behavior monitoring system. The road conditions tested were those with dry and compacted-snow-covered surfaces. After a period of driving involving the roundabout, the drivers were asked to answer a questionnaire indicating subjective assessment of drivability and safety. The results showed that the speeds of vehicles approaching the roundabout when the road was covered in compacted snow were lower than when dry, thereby demonstrating a greater speed reduction effect. Subjective assessment suggested that drivability and safety in compacted-snow-covered road conditions were much lower than those in dry road conditions.

Low temperature thermal cracking is a common type of failure in asphalt pavement that occurs particularly in cold regions or locations with significant daily temperature fluctuations. The resistance of asphalt mixtures to low temperature cracking is generally influenced by the thermal contraction/expansion, visco-elastic, and fracture properties of the asphalt mixture. The accurate characterization of these properties is essential to the meaningful modeling of thermal cracking in asphalt pavements and, thus, the design of thermal cracking resistant mixtures. This paper describes a fundamental approach to determine the visco-elastic properties of asphalt mixtures from direct measurements of thermal stress and strain using a uniaxial test device recently developed at the University of Nevada, Reno. The relaxation modulus was computed in the temperature domain using linear visco-elastic constitutive equation, known as Boltzmann's superposition principle, from the measured, thermally-induced stress and strain during the test. Five distinct stages were identified from the relaxation modulus change with temperature: viscous softening, viscous-glassy transition, glassy hardening, crack initiation, and fracture stages. The proposed approach was used to assess four hot mixed asphalt mixtures made from three aggregate sources with different mineralogy (Quartzite, Limestone and Rhyolite) and two different binder grades (PG64-22 and PG64-28) from different sources. It was found that the evolutions of thermal stress and strain are significantly influenced by the grade of asphalt binder and aggregate source. The relaxation modulus and the derived thermal visco-elastic properties were highly affected by the grade of asphalt binder.

The Alaska Department of Transportation and Public Facilities (AKDOT&PF) tracks roughness data for maintained roads. This is done by using a laser-mounted beam on an SUV-style vehicle. The equipment is operated and maintained by an outside consulting firm and has occurred annually since 2007. The values provided are International Roughness Index (IRI) rutting and Present Serviceability Rating (PSR) for every 20 feet of length per one lane in one direction. The data is stored in spreadsheet form along with Global Information System (GIS) information. The purpose of this study is to explore a simplified approach method for predicting IRI and rutting that could be used in decision making for AKDOT&PF's pavement management system (PMS). Four years of IRI and rutting data were obtained from AKDOT&PF for a major arterial. Subsection and section lengths were selected and averages performed into a final one-mile average. Each year's section average was plotted and a multi-linear regression performed. The equation describing the trend line is then used to predict deterioration of the IRI or rutting value. A PSR was calculated and compared to what had been last measured. Finally, a comparative analysis through visual inspection was performed and compared to the data. The outcome was a multi-linear regression that can be performed and used to predict future pavement deterioration in terms of IRI and rutting. A calibration of the model was implemented using visual inspection. No significant differences were found between the derived model and visual inspection.

Permanent deformation of the unbound granular base course layer is a major factor that influences the structural response and performance of asphalt pavements. It is one of the pavement distress types that requires special attention, especially in the springtime in Alaska. In the past few decades, research efforts have focused on the resilient characteristics of base course materials. However, less effort has been spent on the permanent deformation behavior of base materials, especially for cold-region pavements. In Alaska, D-1 base course materials have been commonly used in pavement construction. Under traffic loading, permanent deformation of these materials exhibited significant variations due to seasonal conditions. Base materials' saturation and weakening due to thawing usually resulted in significant, permanent deformation of pavement structures. This paper describes a series of repeated load triaxial tests which were conducted on D-1 base course materials from the central region of Alaska. These tests aimed at evaluating the effects of the stress state, temperature, freeze-thaw cycling, moisture and non-plastic fines content on the permanent strain of laboratory-prepared specimens. Test results and analyses showed that the increase of fines and moisture contents, and freeze-thaw cycling significantly increased permanent deformation.

The purpose of this research was to compare the surface and subsurface winter temperatures in pervious and conventional concrete pavements placed in June 2011 at the Headwaters Resources Pervious Concrete Demonstration Project in northern Utah. Thermocouples were installed at the site to facilitate monitoring of the air, surface, and subsurface temperatures on hourly intervals from January through December 2012. The collected temperature data were separated into six time periods, defined based on sunrise and sunset times occurring in each month so that the effects of solar radiation would be consistently accounted for in each period. For each of the six time periods, pervious and conventional surface and subsurface temperatures were plotted against air temperature, as measured by the thermocouples. Then, linear regression was used to determine from each plot the air temperature associated with a pavement temperature of 0°C at the instrumented surface or subsurface location. This approach allowed fair comparisons of the two pavement types even when the air temperatures were not identical at every time interval. The results indicate that, for materials and conditions similar to those investigated in this experiment, pervious concrete may be expected to provide greater protection against surface freezing during late morning and early afternoon than conventional concrete of the same thickness. During the warming trends typical of these time periods, the pervious concrete reached 0°C more quickly than the conventional concrete; however, for the other time periods, during which cooling trends may have been more typical, the data suggest that the surface freezing characteristics of the two pavement types were similar. Regarding subsurface freezing, pervious pavements are expected to provide greater resistance to freezing than conventional pavements across all time periods, attributable to the greater latent heat within the former compared to the latter.

Permeable pavements allow water to seep through the bound pavement layer and to be temporarily stored in the unbound pavement layers. Permeable pavements are used in environmentally sensitive areas in order to minimize the effects of the pavement on the natural ground water regime. However, the presence of the water in the pavement structure raises concerns related to frost action in cold regions. This paper investigates the effects of the specific features of permeable pavements on frost depth. Weather data for Anchorage, Alaska was used in the finite element simulations to predict the depth of freeze. The results of this exercise found evidence to suggest depth of freeze under permeable pavements might be less than that of conventional pavements. All modeling in this paper is theoretical. Though the findings of this paper are considered reasonable, more research and modeling must be conducted to make a definitive conclusion.

Pervious concrete mixtures have good freeze-thaw durability in laboratory testing when properly designed. However, translation of laboratory designs to field applications introduces specific challenges and considerations which directly impact long-term durability. This paper includes a discussion of considerations important to good performance of pervious concrete. Certain considerations, such as construction site cleanliness and curing, are applicable to all pervious concretes, but are especially important in freeze-thaw climates. Other considerations, including deicing practices and plowing, are specific to cold regions. Topics will be illustrated using experiences from the mid-west United States, including the world's first pervious concrete overlay, which has been installed at the MnROAD facility in Minnesota since 2008. Since the freeze-thaw durability of pervious concrete is affected by both the mixture and the installation, a companion paper, Mixture Proportioning Considerations for Improved Freeze-Thaw Durability of Pervious Concrete, will provide a discussion of topics related specifically to the concrete mixture. The two papers provide a comprehensive discussion of pervious concrete for cold climates.

Recent U.S. Environmental Protection Agency (EPA) Clean Water Act and Energy and Security Act amendments require stormwater management at private, public, and federal installations. Pervious concrete is a highly permeable material used for stormwater management where detention/retention areas can be placed underneath the pavement for increased site utilization. Although pervious concrete has been successfully utilized in the U.S. for over 40 years, the applications in cold climates only began in earnest around 2006. There still is hesitance to use pervious concrete in cold climates due to the perceived lack of freeze-thaw durability. The authors have extensive experience using pervious concrete in cold climates and this paper will discuss the mixture requirements and options for good freeze-thaw performance. Since the freeze-thaw durability of pervious concrete is affected by both the mixture and the installation, a companion paper, Installation and Maintenance Considerations for Improved Freeze-Thaw Durability of Pervious Concrete, provides a discussion of topics related specifically to installation, construction, and maintenance. The two papers provide a comprehensive discussion of pervious concrete for cold climates.

Over the past 20-30 years, permeable pavement installations have become wide-spread for stormwater control, especially in urban areas. A large amount of design guidance for permeable pavements exists in the literature; however, much of the guidance uses experience and case studies from warm regions. Permeable pavements have been successfully utilized in cold climates for stormwater management and often have ancillary benefits, such as reduced potential for slip and fall. ASCE's Technical Council on Cold Regions Engineering (TCCRE) has assembled the Permeable Pavements in Cold Climates monograph to address issues specific for freeze-thaw climates. The new for 2013 monograph brings together current industry best practices for designing, constructing, and maintaining permeable pavements with considerations specific to cold climates. This paper will provide an overview of the monograph and important areas of design, construction, and maintenance for pervious concrete, porous asphalt, and interlocking permeable pavements.

The Xiaoyangqi River Basin, a typical closed basin in an alpine region in Songling District of Heilongjiang Province in Northeast China, is shown to provide reference data in support of research on snowmelt runoff, an important source for Xiaoyangqi River. First, based on the annual hydrological data measured at the Xiaoyangqi hydrological station on the Burhatong River, the paper estimates the monthly runoff from 1992 to 2010 in the Xiaoyangqi River by using the analogy method. Second, we measured the daily runoff, precipitation and temperature of Xiaoyangqi River during concentrated snowmelt. Finally, on the basis of local meteorological data and the data mentioned above, the paper analyzes the variation of spring runoff characteristics in the Xiaoyangqi River by using Kendall's rank correlation method; the relationship between spring runoff, precipitation and temperature by using SPSS and a multi-regression method; and the relationship among spring runoff, precipitation, snowmelt and temperature during the period of concentrated snowmelt.

Solid-filled causeways have been used along the Beaufort Sea coastline to support oil and gas drilling operations and have provided maritime access on a shallow coast. The Endicott causeway, located in the Sagavanirktok River delta on Alaska's North Slope, has altered the coastal hydrodynamics that transport sediments across the delta. Sedimentation has been observed in the lagoon, shoreward of the Endicott causeway. Past studies have raised concern that infilling of the lagoon may eventually alter fish migration. The main objectives of this research were to determine if the lagoon has continued to infill and if the pattern of infilling is related to the hydrodynamic alterations imposed by the causeway. The results indicated that fine-grained sediment has continued to deposit in the lagoon, and the deposition is related to the placement of the causeway. Further, modeling and analysis indicate that the rate of deposition is currently decreasing.

Research addressing natural processes and control of ground and river icings is well established in national and international technical literature, particularly for large river flows. However, controls applicable to small flow icings are less well documented, providing little guidance for the local engineers who are most often asked to design them. To fill this need locally, the Municipality of Anchorage is developing design guidance for icing controls for small features. The guidance will address controls for icings on ground water seepages and surface flows having discharges less than 0.28 m³/s (10 cfs) and channel widths less than 3.0 m (10 ft). This paper summarizes processes and design concepts basic to the development of this guidance for Anchorage.

During the Austral summer at McMurdo Station in Antarctica, snowmelt runoff can be very heavy. The runoff passes through McMurdo via a system of drainage ditches, gullies, and culverts. During heavy flow, the runoff mobilizes sediment, erodes the drainage channels and embankments, and overflows onto roads. This problem can be minimized by controlling the flow, e.g., via check dams, wooden weirs, or other methods. Important site properties are the steepness of the terrain and drainage paths and the lack of vegetation. Critical to this study is understanding the flow characteristics in the channels. Based on the flow characteristics taken from 2010-2011 field measurements, flow control modeling was developed for an extreme flow scenario in the McMurdo drainage systems. A one-dimensional hydraulic model was used to estimate the impact of weirs during high flow conditions. Owing to the complex environment at McMurdo, three dam designs are being considered for their portability, durability, and practicality, including ease of installation and removal each season. These flow structures included check dams, a wooden weir, and a commercially produced system to help impound the flow during the extreme runoff event. Both the estimated frictional and horizontal ratio and the bearing capacity ratio of the designed structures are greater than one, a requirement of the design conditions. The modeling and preliminary designs are intended to be part of erosion mitigation at McMurdo Station.

Annual resupply of McMurdo Station, the largest US Antarctic research station, is completed in February of each year. After an icebreaker makes a channel to the station, a fuel tanker and cargo ship (carrying roughly 7 million gallons of fuel and 8.2 million pounds in 2012 respectively) arrive at the station before it closes for winter. There is currently no traditional, permanent infrastructure for this activity in McMurdo and offload is completed via an ice pier. This is a large floating piece of manually-thickened sea ice that is connected by cables back to shore. A Bailey bridge allows movement of goods and personnel from the wharf to the pier. Since the first floating pier was built in 1972, the life expectancy of these piers has been roughly 3-7 years. However, due to some local environmental changes, the 1999 pier lasted for a record 10 years before it became unusable due to cracking from wave action. Since 2009, the two new piers lasted only one year. Based on this short life span, alternate designs have been investigated that include making a grounded wharf or incorporating thermosyphons to increase the life expectancy of these piers. Most recently, in 2011, warm local autumnal temperatures and excessive snow accumulation significantly delayed the start of winter construction (manual thickening) to such a degree that a full-thickness ice pier could not be completed. For the offload to be accomplished in 2012, the US Army's 331^st Transportation Company supported the Antarctic program by deploying their Modular Causeway System (MCS). The MCS was built in three days and demobilized in just 36 hours. This paper will review historical pier construction, alternate techniques for future construction and recount the special scenario using the MCS in 2012.

The Nanisivik Naval Facility is a proposed ship refueling station at Nanisivik, in the Nunavut territory of the Canadian Arctic. Nanisivik is the site of a former lead-zinc mine built in the mid 1970's with the support of the Canadian Federal Government by financing portions of the infrastructure, which included the deep sea wharf. With the mine now being decommissioned, the Federal Government intends to reuse the port site, including the wharf. Surveying during a 2010 inspection at Nanisivik indicated that the wharf had settled 2 metres since original construction. Borehole data collected in 2010, along with historical geotechnical data, left engineers searching for plausible ways to explain why the structure had settled so much. Historic surveys conducted by the government, and the 2010 survey, suggested that the settlement of the wharf was continuing, potentially at a linear rate. Regular storm wave overtopping of the wharf requires that the settlement problem be addressed if the facility is to be serviceable for a further 50 years. A second drilling campaign, undertaken in 2011 to depths much deeper than any previous drilling, encountered a deep, thick, permafrost clay layer. This clay is believed to be the primary contributor to the movement of the wharf. The preferred method to reduce the movement is to decrease the permafrost temperature through the use of deep thermosyphons. This paper discusses the history of the site, the investigations, and the options considered to address further settlement of the structure.

In the late 1950's, white painting of the airfield at Thule Air Base, Greenland, was initiated to prevent thawing of ice-rich native permafrost soils that supposedly was the cause of localized depressions in the runway and taxiways. The entire airfield, and most specifically the runway, is currently painted white. This reduces the braking ability of the aircraft and dramatically increases maintenance and labor costs. A multi-phase investigation was conducted to understand the reasoning and efficacy of the painting, and to suggest alternatives to the white painting that could be applied during the next runway repaving cycle. The results of the study show that white painting can be effective if the color is maintained in pristine condition. However, through the half century of paint application, a moderate white condition has existed at best. Additionally, and most importantly, ice-rich permafrost does not exist at shallow, thaw-susceptible depths under the entire airfield. Cost-effective alternatives to the extensive white painting, such as sub-grade insulation or `over-excavation' of ice-rich soils, are available. These localized solutions can be implemented during the next runway repaving cycle, and white painting can be eliminated over the airfield entirely, saving future costs on material and manpower.

The increase in urban population in arctic areas leads to an increased demand for transportation infrastructures (such as roads and airfields) in the regions. This challenges the road constructions in terms of condition, bearing capacity and maintenance. It is believed that deicing agents used on roads and airfields enter the granular subbase materials and thereby makes the soil more frost-susceptible. In this project a series of isothermal frost heave tests has been carried out on granular subbase material from the runway at Kuujjuaq Airport, Québec, Canada. The tests have been carried out in order to determine the frost susceptibility of the material when it is contaminated by a deicing agent. Two series of three freezing tests with isothermal cooling has been conducted using identical saline gradient added through brine. Two types of cooling ramp, an automatic cooling and a manual cooling, were used in order to determine any influence from the cooling ramp. The tests included settings that allowed the samples additional brine during freezing. Hence, the water and salinity were measured before and after the tests in order to determine the redistribution of water and salinity. The test results do not support the theory that a saline gradient effectively can replace a thermal gradient and create favorable conditions for frost heave. There was no evidence of ice segregation during the tests. During freezing, heave of maximum 0.02 % was observed which, however, is not considered to be caused by ice segregation, but rather a volume increase by fusion caused by a small amount of pore water. The direction of the frost front could not be determined from the collected test results, and no reduction in bearing capacity or increase in frost susceptibility can be derived from the collected data on the granular subbase material.

This paper discusses the unique challenges that can be encountered during the design and construction of airfield pavements in remote areas and under harsh climatic and soil conditions in the North. The case study will identify the problems encountered and the solutions that were implemented or recommended to overcome these issues. The case study is about the Runway 13-31 pavement major rehabilitation at Churchill Falls Airport in Labrador. The airport is located in a very remote area with very limited access to paving materials and contractors. In addition to the remoteness of the airport, it also experiences harsh winters and a frost penetration depth of approximately 3.0 m below the ground surface. Subgrade soils at the airport are comprised of a frost-susceptible glacial till underlain by a shallow, undulating bedrock. Extensive Ground Penetrating Radar (GPR) survey was carried out to map the depth to bedrock. The primary distresses on the runway pavement were extensive frost heaving and cracking. The shallow bedrock was also a significant challenge that had to be considered in selecting feasible rehabilitation alternatives. Five pavement design alternatives were considered: (1) reconstruction without grade raise; (2) reconstruction with 0.5 m grade raise; (3) rehabilitation, including pulverizing existing pavement; (4) rehabilitation, including installation of polystyrene insulation (5) pavement rehabilitation without grade raise. Drainage improvements included deepening an intercepting ditch and construction of new subdrains along both edges of the runway. Subdrains design included very extensive rock cuts. Although the Life Cycle Cost Analysis indicated that the most cost effective was Option 2, the Client decided to go ahead with Option 5 which had the lowest initial cost. Major construction issues included difficulties with obtaining good quality aggregates and proper asphalt cement grade, asphalt mix production in very remote location, deep rock cuts and difficult soil and weather conditions.

Hokkaido, the northernmost island of Japan, is characterized by a cold, snowy climate. Snowfall and road freezing there cause driving conditions to deteriorate in winter. This results in various traffic hazards, including increases in traffic congestion and traffic accidents. Physical measures that have been continuously implemented to minimize these problems include the spreading of anti-freezing agent and the development of snow removal systems. However, little effort has been made to conduct transportation demand management (TDM) except for the provision of visibility information to drivers for driving safety or traffic control. Although TDM has not been utilized as a solution for winter traffic issues, its necessity and measures have been intensively discussed in the field of transport engineering. This study outlines two trial cases of Mobility Management (MM) that encourage commuting mode changes from car to public transportation as kinds of TDM and examines the results. The MM trials were conducted in winter in Sapporo. One MM trial used questionnaires and the other used a website. In both trials, subjects were requested to report their commuting transport details, including transport modes and trip time. Tthey received feedback from the trial organizer on their commuting transport behavior. In both trials, some subjects changed their commuting mode from car to public transportation as a result of the information provided, including the feedback given by the organizer and public transportation promotional materials. These results indicate that MM has the potential to encourage people to use public transportation. Increased public transportation use in a cold, snowy city like Sapporo could reduce the traffic congestion that significantly worsens in winter from snowfall and road icing, while realizing environmentally friendly transport.

Pedestrian falls in winter in Sapporo, Hokkaido (Japan) have been a serious problem that requires an urgent solution. Pedestrians who fell severely enough to require ambulance transport to hospitals in winter have numbered between 600 and 800 a year. Pedestrians are prone to falls on slippery, icy road surfaces. Icy surfaces on roads and sidewalks form by a process that differs greatly from that of icy surfaces of natural snow cover, because the ice on roads and sidewalks is created by the compaction, breakage and re-compaction of snow by the pressure of passing heavy vehicles and pedestrians. In this study, icy sidewalk surface slipperiness and weather conditions were monitored in January and February 2009. Sidewalk surface ice core samples were taken to survey the microstructural characteristics of the ice when the sidewalk surface was particularly slippery. The survey results identified the typical weather conditions that lead to the emergence of an extremely slippery sidewalk surface: intense snowfall of 10 cm or more followed by a series of days with daytime positive temperatures without snowfall. They also proved that when the density of the sidewalk surface layer is 500 kg/m³ or greater and the surface temperature of the layer is -2°C or higher, the slippery, icy sidewalk surface is most likely to emerge.

This study proposes a model that forecasts visibility in winter on the basis of a CCTV-Camera-Based Road Visibility Information System (RVIS) that was developed by the authors to minimize winter hazards, including traffic accidents resulting from snowstorm-induced poor visibility. The RVIS quantifies road images recorded by multiple closed-circuit television (CCTV) cameras along the roads to automatically apply the quantified information to pre-defined visibility indexes that indicate levels of road visibility. To quantify the road images, the weighed intensity of power spectrum (WIPS) is calculated such that its magnitude represents the difference in spatial frequencies. When road visibility decreases from snowstorm or fog, the contrast of road view contained in the CCTV camera image decreases. From WIPS values, the road visibility index (RVI) is calculated. The RVI is categorized into 4 ranks for greater understandability by users: Level 1(≧500 m), Level 2 (200~500 m), Level 3 (100~200 m) and Level 4(<100 m). From the RVI ranks, road users can know the visibility level on the route where they are planning to drive. The objective of this study is to develop a visibility forecast model utilizing the RVIS. To achieve the goal, we used the data of the WIPS values and RVI ranks recorded by the RVIS, as well as 1-km-mesh meteorological data recorded by the Japan Weather Association. A feasibility study on the visibility forecast model was conducted during the winter of 2009-2010 at a 35-km section of National Route 40 in Hokkaido, Japan. In the study, 1-km-mesh meteorological data were used to estimate the WIPS values and RVI ranks a few hours ahead of time by employing a multiple-regression model and the Kalman filter. The relationship between WIPS data from road images as dependent variables and the meteorological data as independent variables was examined to compare the accuracy of WIPS estimation between the two models. As a result, the correlation coefficient for the Kalman filter indicated better fit than that for the multiple-regression model. Thereby, the Kalman filter was identified to be more applicable than the multiple-regression approach to create a road visibility forecast model.

In cold, snowy regions of Japan, it is considered important to understand changes in winter climate conditions in order to enable contribution to the development of long-term snow and ice control plans and measures. In this study, a method of estimating snowy climate values for use in future projections with a global climate model was investigated. Formulas to support the estimation of snowy climate values (e.g., transport rate of drifting snow) were initially created using past meteorological data, and future projection data were substituted into the formulas. The results indicated that the predicted means of snowy climate values were lower than the present values at two points in Hokkaido. In future work, the authors plan to create future distribution maps showing snowy climate values in cold snowy regions of Japan for utilization in winter maintenance work.

The ice surface antiskid problem in the cold region in winter has always been a difficult question which needed to be solved by the winter road maintenance department. Therefore, we have developed an anti-freezing measure by using by-products produced in a food processing process. The by-products mixed in the road surface coating materials are released as a form of ions onto the road surface and they are able to rapidly melt snow and prevent roads from freezing under the freezing rain or snowy weather.

Flat-loop evaporator thermosyphons are commonly used to provide subgrade cooling beneath at-grade structures founded on thaw unstable permafrost. There are few published articles on how the flat-loop evaporator thermosyphons perform in service. In order to provide in-service performance data, a standard commercial unit was instrumented and installed beneath a heated slab-on-grade structure at Deadhorse, Alaska. The thermosyphon was activated on March 1, 2009 and has been monitored since. The data logger has been continuously recording evaporator surface temperatures, evaporator surface heat flux, ambient air temperature and wind velocity at 3-hour intervals. The data shows that the thermosyphon removed enough heat to freeze a layer of soil approximately one meter in thickness beneath the subgrade insulation in the first month of operation. The temperature data shows the thermosyphon performance for three complete winters. The data from the heat flux sensors was used in an attempt to quantify the actual thermal conductance of the thermosyphon. The measured conductance value is reported. However, it is suspect when compared to the predicted values based on the measured climatic conditions. Recommendations for specifying and designing subgrade cooling systems using flat-loop evaporator thermosyphons are presented.

Assessing the performance of railway track structures in Finland has become increasingly important as engineers seek to develop improved designs and more effective maintenance and rehabilitation strategies that improve safety, increase service life, and reduce life-cycle costs. Through extensive research, several factors affecting the performance of railway track substructures have been identified and studied. The purpose of this paper is to provide an overview of the main research findings and recommendations pertaining to ballast, sub-ballast, frost action, track stiffness, and embankment stability. While material specifications, design procedures, and construction methods have been developed to ensure adequate performance of track substructures in new construction, special challenges exist with respect to managing existing tracks that were not designed for modern conditions. Safety and riding quality demands mandate high smoothness from high-speed tracks and set high standards for track construction and maintenance, especially on mixed-traffic lines where heavy freight trains are also loading the track. In addition, humid and cold winters and very weak subsoils in many areas add complexity to the problem.

The Alaska Energy Authority (AEA) has been authorized by the State of Alaska to develop the Susitna-Watana Hydroelectric Project on the Susitna River, approximately 60 miles northeast of Talkeetna, Alaska. The purpose of the project is to help meet the future electrical needs of Alaska's Railbelt region. As currently envisioned, the project would include a single dam approximately 700 feet tall with a 20,000 acre, 42-mile-long reservoir located below Watana Creek. Under one option, the dam will be constructed of roller compacted concrete (RCC) and have the capacity to generate 600 megawatts. If constructed, it will be the largest dam and reservoir in the state and one of the few sub-arctic RCC dams in the world. To assist with the design of the project, geotechnical investigations were conducted to characterize the subsurface conditions at the dam site, related structures, potential material sites, and reservoir. The objective of this paper is to provide a brief overview and history of this project, the geologic and geotechnical investigations that have been conducted since the late 1970's, the general geotechnical conditions (including permafrost) in the vicinity of the proposed dam, and the logistical constraints associated with carrying out geotechnical investigations at such a remote location. This remote proposed dam is sited on a narrow reach of the river bound by canyon walls composed primarily of igneous intrusive bedrock, chiefly diorite. Subsurface investigations in the early 1980's determined that bedrock under the river channel is overlain by approximately 90 feet of coarse alluvial sediments. Borehole instrumentation indicates presence of localized permafrost on north-facing slopes. Investigative efforts at the site were complicated by a number of constraints including its location being more than 35 miles from the nearest road and 60 miles from the nearest town, need for helicopter access, severe winter conditions, and wildlife issues.

One commercial building and three residential buildings, each with enhanced shallow foundations constructed over perennially frozen coarse-grained soils, were selected as case studies demonstrating current experience with typical thaw-strain analysis of frozen sands and gravels and current methods used in Fairbanks, Alaska to reduce problems associated with thawing coarse-grained soils. Some typical foundations in use for between 7 to 13 years were re-examined and the owners were interviewed. Actual thaw-settlement and related movement was estimated in each case and a history of maintenance was obtained. This information is presented to enhance the understanding of the thaw settlement behavior of frozen granular soils and to advance the practical application of cold regions geotechnical engineering.

In the past, engineers have often tried to build stable structures on ice-rich permafrost by providing means to keep underlying soils frozen. In an era of global warming, however, such efforts may be futile where soils are already near thawing temperatures. If development in such areas is to occur, engineers will increasingly need to design structures that can accommodate a thawing world beneath them. The author relates his experience with his own home, built in 1953 over ice-rich warm permafrost and continuously occupied while the frozen soils thawed entirely from beneath its heated basement. Four feet of differential settlement (thaw subsidence) was experienced during this process, requiring repairs on several occasions. Following thawing, drainage and consolidation of the silt soils, the foundation was replaced in 1999 with a conventionally built basement that has remained stable for more than a decade. The author discusses design features and other conditions that allowed for the successful continued use of the structure despite the extreme distress of the supporting soils. Lessons learned and areas where additional research might be productive are discussed with the illustrative examples.

While general inspections are performed on all public bridges in Finland every 5 years, special inspections are warranted when the extent of structural or functional deficiencies mandates action. On concrete bridge decks, the development of deficiencies is often associated with the gradual failure of deck waterproofing systems. Special inspections are initiated to determine the type and extent of damage so that appropriate rehabilitation decisions can be made. The purpose of this paper is to describe the strategic field sampling and advanced laboratory testing involved in special inspections of concrete bridge decks in Finland and to document through a case study how the data are used in making engineering decisions about deck rehabilitation.

Industry standard practice is data integration at a data system level, e.g. connecting the geospatial systems, work management systems and the financial software platforms. Anchorage Water & Wastewater recognized that data integration needed to expand beyond connecting software platforms into developing Information Value Chains, so that the best value information could be available at the lowest cost with the highest degree of accuracy. This has resulted in processes relying on integration of the analytics with the various software platforms for each level of planning processes, from tactical planning relying on the spatial and work management system data to long range financial planning based on evaluating the business value of information at each step of information flow.

The construction practices used by American and international companies rarely consider local indigenous input or local traditional building methods and cultural norms. This applies not only to community development projects in Arctic villages, but also to projects in war-torn countries requiring capacity or nation building. In this case, where sustainability framework is missing and not incorporated, the infrastructure development is likely to fall apart. Sustainability refers to a framework that deals with the environmental and societal aspects, as well as the economics aspects of sustainable development. The ideal would be to value the three equally in the analysis and the design, decision, and execution processes. Collaborative research and learning strategies for infrastructure sustainability in remote areas are keys to construction success in local communities. Learning and teaching processes adapted to the Arctic are necessary to promote local leadership and ownership of Arctic infrastructure. The academic community, practitioners, and decision-makers will have the continuing role of incorporating the concept of sustainable infrastructure development globally, including in the Arctic. This paper highlights the importance, the challenges, and the opportunities for researchers, engineering practitioners, and academic members to apply sustainability practices. A holistic sustainability framework is discussed for integrating capacity building with emphasis on partnership, awareness, and knowledge building for engineering and infrastructure development in the Arctic.

The paper will present the interim results of a multidisciplinary research project, Integrative Urban Development Concept: Case Sustainable Winter City (2012-2014). The research project examines integrative urban development practices, tools and block-level concepts that are needed in the design and construction of a Sustainable Winter City. These practices are tested and piloted in a Living Lab experiment in the city of Oulu, northern Finland, where a new Hiukkavaara neighborhood for 20,000 inhabitants is being constructed. Planning and building of western cities and communities is based strongly on a tradition of modernistic urban planning. Modernistic planning principles consist of distinction of activities and traffic as well as creation of scattered urban pattern. All these features can be recognized in the urban structure of the city of Oulu and other large northern cities - suffering of long internal distances, dependence on private cars and heavy ecological footprint. Urban sprawl has though come to its' end since climate and energy questions have pushed design of sustainable urban structure into political agenda in global, national and local levels. This sets demand for a new kind of integrative, public-private co-operation and partnerships in order to create sustainable northern communities. The paper will focus on discussing what kind of integrative planning practices and tools are needed to realize a sustainable northern winter city. Key questions are: 1) What kind of urban development practices and tools are promoting planning and building of a Sustainable Winter City (SWC)? 2) What are the obstacles and promoters in implementation of the SWC practices? 3) How should current practices and tools be renewed and what kind of new practices and tools are needed?

In 2009, Anchorage Water and Wastewater Utility (AWWU) began using a qualitative risk matrix to evaluate the relative importance of projects and better prioritize capital projects. Assets were evaluated and systematically assigned consequence and likelihood of failure, and, as a result, a risk score. The two limitations of this initial approach were: 1) subjective rather than objective measurements, and 2) difficulty in identifying the optimal timing of capital work. In order to address these two limitations, AWWU contracted with InfraPlan to assist in developing a process to identify the optimal timing for replacement for water pipe assets using objective measureable factors. This process was a collaborative effort involving two tools provided by InfraPlan, Casses and Economic Pipe Replacement Model (EPRM), along with scripting developed by AWWU to quantify consequence of failure. Casses is an advanced statistical tool that helps quantify the likelihood of failure of each pipe each year in the future using historic causal factors. InfraPlan assisted AWWU in developing the original datasets and trained AWWU staff in operating the software. In parallel, AWWU staff developed an in-depth triple bottom line consequence analysis quantified in dollar terms at the pipe segment level using advanced Geographical Information System (GIS) analytical techniques and scripting processes (FME Workbench). This resulted in being able to quickly (push of a button) run updated system-wide consequence analysis, and to update the scripting with additional consequence factors as the information becomes available. These two steps have removed the subjective nature of risk categorization and also allowed for evaluation of future risk. A final tool (EPRM) is then used to combine forecasted inflation and cost of capital rates, the quantified likelihood and consequence, and replacement costs to determine the optimal timing for R&R work. This analysis can be continuously updated when new data becomes available (or its quality improves).

Anchorage Water and Wastewater Utility's (the Utility) historic Strategic Asset Management Modeling efforts have been predicated upon maintaining current service levels and based on life estimates derived from industry and depreciation life. In order to better illustrate the relationship between operational and capital expenditures and level of service, the Utility reassessed the tolerance for failure for water pipes based on consequence of failure for each pipe. This tolerance for failure was then used to determine the estimated pipe life based on derived pipe failure curves. The major shift in modeling, as compared to the Utility's previous modeling, came from a very simple, yet powerful, change in the understanding of real world pipe situations: it is acceptable for pipes to break as long as the Utility has the maintenance capacity to repair the pipe in a reasonable timeframe and service levels are maintained. While this has always been understood, it hasn't appeared to have been built into many models. By assessing the consequence of failure for each pipe segment, the Utility was able to assess which pipe segments had greater impact on service levels in the event of a break, either through supply issues (e.g. transmission mains), service interruption (e.g. hospitals), or the duration/cost of repair (e.g. deep bury pipe). By evaluating service life based on consequence of failure, the Utility was able to model the impact the shifts in budgeting have on future levels of service. As a result of this change, the Utility was able to re-allocate and reduce capital replacement needs funding by significant amounts (20% per annum), with minimal expected service level impacts while also planning for increased Operation & Maintenance funding to reflect the increased tolerance for low-impact failures.

The mechanical properties of wood-plastic composites (WPCs), like the polymers that comprise them, are extremely sensitive to temperature. While several WPC's have been tested in tensile creep at high temperatures, little data has been collected at cold temperatures. These materials are currently being used in cold regions in many infrastructure applications in Alaska without research into how the low temperatures will affect their mechanical properties. This study characterizes the behavior of a commercial WPC at both room (25°C) and cold (-10°C) temperatures and includes both quasi-static and creep testing. It was shown that the cold temperature causes an increase in the ultimate stress and initial modulus of elasticity of the WPC while the failure strain was unaffected. Furthermore, when the tensile creep response is represented by a power law, the time-dependent exponent of the composite is unaffected by the cold temperatures. Additional testing at multiple cold temperatures is required to determine if WPCs time-dependent exponent will remain constant over continued decreasing temperatures.

Sewage treatment in Arctic towns is inadequate. Sewage contains pathogenic microorganisms, parasites, antibiotic-resistant bacteria, and toxic compounds. Discharging of untreated sewage can thus have a negative effect on people's health and the aquatic environment in the receiving water bodies. Conventional treatment is challenging and expensive to implement in Arctic communities due to the cold climate and scattered population. In addition, advanced removal of nutrients may, in many cases, be overstated due to the low population density and large receiving water bodies. In this work we investigated the presence of Total coliforms, Escherichia coli (E-coli), enterococci, streptococci, antibiotic-resistant enteric bacteria, and toxicity in sewage from two sewer outlets in Sisimiut, West-Greenland, as well as in a sub-stream from the local hospital. According to the content of streptococci and enterococci, the wastewater is very strong, suggesting a potential hygienic risk. In addition, a high fraction of antibiotic-resistant bacteria and an increased toxicity in the sub-stream from the hospital, suggest that this stream contains toxic compounds, possibly antibiotic of nature that may affect the local Arctic marine environment negatively. Both peracetic acid treatment and UV-C radiation show potential for disinfection of the wastewater after removal of solids >60μm. E-coli was most susceptible to peracetic acid treatment, while a maximum possible reduction of enterococci and coliforms of 2-3 size orders was observed. The highest reduction observed by UV-C treatment was 4 size orders for enterococci, but no maximum level was observed. UV-treatment may thus be a preferred disinfection method, in particular for a community with long transport distances to the nearest chemical supplier and access to hydropower from a local hydropower plant.

Different scenarios affect the efficiency of pumping systems, especially those in cold regions. Increasing the efficiency of pumping systems conserves energy, making water distribution more environmentally friendly. Issues pertaining particularly to cold regions are regularly disregarded, but these issues should be acknowledged for improvements to operate efficiently. Inefficient design may contribute to problems with water distribution in cold regions. These problems include, but are not limited to: freezing of water towers, pipe seals stretched beyond their elasticity, and drawing water from a frozen, pressurized body of water. Field observations of problematic occurrences related to cold climate were completed through field visits. Pipe-network software, WaterGEMS (Version 8.i), is utilized to simulate a scenario for two different pipe networks, which analyzes the water distribution conditions that occur within a freezing standpipe, specifically the efficiency of operating the pumps within the pipe distribution network. To replicate freezing, the diameter is decreased incrementally while the pumps reactions are analyzed to gage the cost increase due to the change in diameter per length segment. Comparisons between normal conditions and freezing conditions show how freezing of the standpipe of a water tower may result in system inefficiencies. The research questions are: how efficient are the pumping stations if the stand pipe were to freeze? and, at what level of inefficiency is it better to choose different pumping or distribution alternatives? Different opportunities are identified for further research to improve the efficiency of water distribution in cold regions.

Tyonek, Alaska is located on a bluff on the northwest shore of Cook Inlet, approximately 43 miles southwest of Anchorage. Two deep groundwater wells provide the raw water source for Tyonek. Concentrations of arsenic, iron, and manganese in the raw water exceed regulatory maximum contaminant levels (MCL) of 10 μg/L, 0.3 mg/L, and 0.05 mg/L, respectively. The existing water treatment process at the time of study (filtration through two bag filters in series followed by chlorination) was not able to meet regulatory requirements of EPA's Arsenic Rule and Secondary Drinking Water Standards. A pilot-scale direct filtration study was conducted to identify a water treatment process that could produce finished water that meets the EPA standards. An additional objective of this study was to develop a 95% efficient treatment process (cost-effective) with minimal oversight (simple operation). The pilot study was setup at the existing water treatment plant. Three different media configurations in combination with various chemical (chlorine and ferric chloride) injection configurations and filter hydraulic loading rates (gpm/sf) were evaluated. Chemical dosages were varied based on jar test and field sample results. Field screening and laboratory samples were collected to characterize the raw water and effluent from the pilot-scale pressure filtration system. The results indicated that an iron/arsenic co-precipitation process using chlorine and ferric chloride can efficiently reduce arsenic by 95%; both iron and manganese concentrations were reduced by 93%. Based on the pilot study results, a full scale water treatment system (40 gpm design flow rate) was constructed. The treatment process includes the addition of chlorine and ferric chloride to oxidize and coagulate, respectively, the raw water arsenic concentrations, followed by two five-foot pressure filters in parallel. The full-scale water system is currently effective in removing arsenic, iron, and manganese concentrations below their respective MCLs.

The City of Saxman in southeast Alaska currently obtains raw water from a surface water impoundment located on Saxman Creek. In addition to high turbidity and color, Saxman had problems periodically exceeding disinfection by-products (DBPs) maximum contaminant levels (MCL). The quantity and quality of the raw water obtained from Saxman Creek is known to vary significantly based on seasonal changes and/or precipitation events. Based on the raw water quality and required treatment efficiency, treatment scenarios were identified that were effective for removing >90 percent of the total organic carbon (TOC), with comparable reductions observed in the DBP formation of the treated water. To achieve the required goals, the coagulant ferric chloride (FeCl₃), Nalco 8185, and Nalco 8105 were evaluated during pilot testing. In addition, these studies also evaluated MIEX® pretreatment of the raw water followed by coagulation using a polymer coagulant Nalco 8185. Results obtained from pilot study and full-scale treatment plant using MIEX® resin in conjunction of Nalco were very promising with respect to color (removal >95%), turbidity ( removal >95%), TOC (removal >85%) and DBP formation precursors (reduction >95%). This paper summarizes the results of onsite direct-filtration water-treatment studies and full-scale water treatment plant performance at Saxman, Alaska.

Hooper Bay is a relatively large Yupik Eskimo community of approximately 1,137 residents located in the Yukon-Kuskokwim Delta, on the west coast of Alaska. As the population of Hooper Bay grows and more customers are connected to the new water and sewer system, wastewater loading on the existing treatment lagoon will increase significantly. This increase in loading has the potential to go beyond the hydraulic and organic capacity of Hooper Bay's existing lagoon in its current configuration. The implementation of wastewater treatment improvements in cold region communities, such as Hooper Bay, presents a number of challenges in terms of design, construction, operation, and maintenance due to the arctic nature of the territory. A review of literature specific to cold regions engineering produced a set of design criteria that was used to evaluate the current capacity and future wastewater treatment needs of the community. An analysis of the existing wastewater treatment lagoon confirmed that the existing lagoon does not have the hydraulic or organic capacity to meet Hooper Bay's needs for a 30-year design life. Therefore, wastewater treatment system improvements are required. Following an extensive examination of feasible alternatives, converting the existing system into a multi-cell, facultative wastewater treatment lagoon with settling tanks is the recommended alternative for Hooper Bay's wastewater treatment improvements. This alternative is reliable and less expensive to construct, operate, and maintain than other alternatives. Most importantly, it meets the hydraulic and organic loading requirements for the 30-year design life.

Various types of water delivery systems have been built in Arctic and sub-Arctic Alaska, including watering points, central facilities, trucked haul system, and piped utilities. These different systems provide varying levels of health benefits primarily related to the cost of delivery and resulting quantity of water available for use. Of the numerous types of piped water distribution systems, five have been used with success. These include the single main recirculating (pitorifice) system, the slow main/individual circulating pump system, the extended main system, the dual main system, and the heated utilidor system. All of these systems use looped mains in which water is heated, pumped, and circulated to prevent freezing. Additional heat may be added via supplemental warm make-up water or by passing some portion of the circulating water through a heating unit. Water in the house service lines is circulated back through the mains by energy from differential pressure pumps or main line pitorifices. The analysis of circulating heated water distribution systems is complex and has generally been limited to hydraulic and thermal calculations of simple cases and often using factors derived from field experience. The recent availability of public domain and proprietary hydraulic software, however, provides an avenue for thermal-hydraulic modeling through analogous chemical kinetics subroutines. Conductive heat gains and losses can be substituted for first-order chemical reactions used to model water quality in these computer programs by applying equivalent analogies to the governing equations for these two processes of water-quality dynamics and heat transfer. This paper provides an historic perspective on the development of cold regions water distribution systems in Alaska, summarizes current practice, and presents the development of a thermal-hydraulic modeling approach to a circulating community water system for use in hydraulic/water quality modeling software.