A new technique for protecting roadways from damage due to thermal degradation of underlying permafrost is investigated. The technique relies upon the use of an open graded aggregate for construction of the major portion of the embankment. Such a material allows winter-time natural convection to occur within the embankment thus increasing cooling of the embankment and permafrost foundation during winter months and preserving the permafrost layer. Both experimental and numerical investigations have been carried out in order to assess the performance of these embankments. Numerical simulations show that they can lower subgrade temperatures by 5°C or more, on an average annual basis compared to standard roadway embankments. Field measurements made in an experimental air convection embankment located near Fairbanks, Alaska have confirmed the existence of convective eddies within the embankment during periods of cold weather, as predicted by the numerical model. Temperature measurements taken below the embankment indicate that a permafrost layer began to develop beneath the embankment even though none existed prior to construction.

Foundation designs for nonthaw-stable permafrost commonly include piles or post and pad foundations designed to thermally isolate the structure from the ground surface, thereby reducing the transfer of building heat and subsequent thawing of underlying permafrost. Although these foundations are cost effective and common for many structures, they are less desirable for heavy structures or structures that are designed for high live loads. The concept of constructing structures on a passively refrigerated gravel pad has proven to be a valuable and effective foundation design alternative for foundations on nonthaw-stable permafrost.

Frost heave in fine-grained soils during freezing, and loss of strength during the subsequent thawing causes extensive damage to structures (i.e. roads, airfields, buildings, retaining walls, pipes, etc.) built in cold climates. There are several extrinsic and intrinsic factors that influence frost heave. Loading is one of the extrinsic factors which have been widely discussed by researchers in the literature. This factor (together with frost depth and water table depth) controls the depth to which frost susceptible soil must be replaced if frost heave beneath a structure is to be avoided.

The present paper attempts to quantify the sensitivity of frozen ground strength to temperature increase that may result from general climate warming, and proposes a simple strength-sensitivity index that could be used as a basis for mapping the zones of potentially stable and unstable permafrost, with the purpose of estimating the potential damage to the existing structures, and drafting the design guidelines for future projects.

This paper reports on the evaluation of two surface modification techniques to reduce permafrost degradation below roadway embankments. Snow management on side slopes was computer modelled and field tested. Results showed a 20% increase in freezing n-factor. A second method consisted of placing quarry rock to a depth of 1.3 m on side slopes. An increase in freezing and decrease in thawing n-factors of 150%, respectively were measured. This yielded a reduction of the MASST of 8°C. The porous rock cover allows natural convection to occur during winter and provides stable layer of insulating air and solar shading during the summer.

To evaluate the potential use of spray freezing technology in removing inorganic and organic contaminants from recycled oil sands tailings pond water, a field study was carried out at the Syncrude Canada Ltd. mine site in February 1994. A plastic lined containment area was prepared to collect the spray ice.

Naturally occurring organics may be reported as false positives during environmental testing, since they are often similar in molecular weight and chemical character to anthropogenic hydrocarbons. Background concentrations of diesel range organics (DRO) as high as 3,600 milligrams per kilogram (mg/kg) in soil and 0.62 milligrams per litre (mg/L) in groundwater have been reported in Alaska using EPA Method 8100 modified. In some cases, these background concentrations are above state regulatory cleanup levels for DRO.

The Water Research Center participated in a multi-year study to provide a quantitative description of the effects of discontinuous permafrost on contaminant transport in the groundwater at Fort Wainwright, Alaska. A critical part in formulating a remediation strategy is the development or adaptation of appropriate analytical and numerical models to predict the contaminant pathways. Primarily interested in the migration of contaminants dissolved in groundwater, we utilized solute transport models that incorporate both advection and dispersion and can also include the effects of retardation of the solute with respect to the local groundwater velocity. After collecting appropriate hydrologic and water quality data, we performed tracer tests to allow us to estimate several key aquifer parameters. We then performed both analytical and numerical plume modelling calculations to predict plume migration. The results show the possibility of a westward migration over a period of decades, with the permafrost distribution significantly affecting the direction of flow.

The Alaska Department of Environmental Conservation (ADEC) has established cleanup levels for contaminated soil generated by releases and spills from fuel storage tanks (FSTs). In the process of decommissioning and replacing its current inventory of FSTs, the Federal Aviation Administration (FAA), Alaska Region, has encountered varying degrees of contaminated soil requiring treatment. This paper presents treatment results for two biocells operating at the McGrath Station; specifically, it describes biocell treatment system design and operating parameters, and tracks demonstrated hydrocarbon removal rates and trends for gasoline-range and diesel-range organics.

The establishment and enforcement of cleanup standards for hydrocarbon-contaminated soil and groundwater has led to the rapid evolution of remedial technologies in Alaska. A pilot-scale treatability study was performed at Fort Wainwright, Alaska, to investigate the feasibility of using air injection/soil vapour extraction (AI/SVE) for remediation of contaminated soil and groundwater. The study focused on monitoring remediation rates resulting from volatilization and biodegradation in the vadose and saturated zones. Study objectives included the assessment of contaminant removal rates for each identified treatment process and the estimation of the treatment time required for site remediation. This paper summarizes the results of hydrocarbon removal rate measurements and presents a method for estimating the time required for site remediation.

A laboratory experimental program was conducted on 30 cm high, wet tamped soil columns of silty sand with a layer of diesel contaminated soil placed on the surface. The soil was cyclically thawed then frozen from the upper surface to approximately half way down the column, maintaining the lower portion of the soil column in a frozen state for the duration of the test program. The results showed considerable migration of diesel into the saturated uncontaminated soil which was subjected to cyclic freezing and thawing, however, no contamination was observed in the permanently frozen soil after up to 8 freeze-thaw cycles.

A study was conducted to assess ways to minimize thermal protection requirements for cold weather masonry construction. Frost damage immunity thresholds in terms of mortar moisture content and maturity were determined. Correlations of moisture content with time were developed for mortar in contact with masonry units. Guidance for when fresh mortar can be allowed to freeze, how quickly water can be withdrawn from fresh mortar by masonry units, and at what water content mortar first becomes immune to frost damage are provided. The effects of temperature and antifreeze admixtures on the strength and durability of mortar were studied.

In recent years, attempts to eliminate deicing salts and moisture penetrations have been made by applying surface coatings and sealers to the concrete surface. Although use of sealers and coatings has met with varying degrees of success, it is not uncommon for them to cause earlier failure and uneven discolouration of the concrete surface, thereby degrading the aesthetics of the structure. In addition, new coating systems emerge on the market almost every day. Many engineers in cold regions continually face the challenge of selecting a proper coating system for construction projects.

The development of a rational evaluation method that can be applied to greases subject to low temperature service is attempted using a two level approach. The greases are evaluated as to their expected performance based on criteria that are currently believed to be important. The actual performance of the greases is then assessed in service on a railway hauling iron ore in northern Sweden and Norway under severe conditions of low temperatures and heavy duty demands. The relevance of the expected criteria in predicting actual performance will be used to establish a weighting system for each criteria to develop an overall performance number that can be used for rational selection of greases for low temperature service.

Long-term paint/coating exposure tests in an arctic climate have been carried out by NKK because very little is known about the effectiveness of corrosion prevention measures for steel structures under arctic conditions. Twenty-one types of standard and heavy coating systems are under exposure tests at Fairbanks, Alaska. This paper presents the results of a survey of the coatings after 13 years exposure. Zinc rich and epoxy/urethane coating systems have provided the most durable long-term service in the arctic climate. Chlorinated rubber and vinyl chloride resin paint films cracked and do not appear to be appropriate for arctic service.

It has been estimated that the cost of protecting freshly placed concrete from freezing exceeds $800 million annually (Flynn, 1992). Previous research has investigated the compressive strength and rebar pull-out strength of concrete cured below 0° Centigrade which was batched by using calcium nitrite and sodium nitrite as antifreeze admixtures (Korhonen, 1991) (Wood and Schroeder, 1993) (Schroeder and Wood, 1996). Concrete prepared in this manner is called cold weather concrete. There have been no reports in the literature evaluating the freeze-thaw durability of cold weather concrete prepared with antifreeze admixtures and subjected to cyclic freeze-thaw during curing. This study investigated the compressive strength of cold weather concrete when subjected to cyclic freeze-thaw during the first 28 days of cure. Results indicate that cold weather concrete mix used in this research and subjected to cyclic freeze-thaw developed strengths in the range of 17.25 MPa.

A workshop on the status of research was held at the 1994 Cold Regions Engineering Specialty Conference in Edmonton, Alberta to explore how a professional society could advance the state of knowledge regarding cold regions engineering. Forty people from a wide variety of backgrounds took an active part in the discussions. Ultimately, a list of specific topics was developed, which will be used by the American Society of Civil Engineers (ASCE) Technical Council on Cold Regions Engineering (TCCRE) Research Committee and their Canadian counterparts in an attempt to promote research in cold regions.

The impact of a buried chilled gas pipeline is directly related to the growth of frost bulb surrounding the buried pipe. Estimation of the size and rate of growth is important to assessing potential engineering problems and choosing the appropriate solutions. Frost bulb growth calculations, however, could involve significant computation effort that requires the use of advanced numerical models for heat and moisture migration. In this paper, simple chart solutions using dimensional analysis were developed to determine the frost bulb growth. These solutions were based on results from numerical analysis that account for ground surface temperature, pipe temperature, depth of pipe embedment, and depth of permafrost boundary on the corresponding frost bulb growth around the buried pipe. Dimensional analyses were used to group the significant variables into dimensionless parameters and produce simple charts for predicting the size of frost bulb and its rate of growth.

A 10 inch (25.4 cm) diameter, 147 mile (237 km) long natural gas pipeline was installed across the North Slope of Alaska’s Brooks Range in the late 1970’s. Several sections of the pipe have been exposed at the ground surface in a 6.7 mile (10.8 km) segment on the Arctic Coastal Plain. The process appears to result from upheaval buckling of the pipeline driven by thermal expansion. Poor restraint by thawed and saturated cover soil is a major contributor to the problem.

A mathematical optimization model is developed for quantitatively evaluating the options available for transportation of North Slope natural gas. The model considers environmental factors of the North Slope, transportation infrastructure in the arctic, economic considerations, production, distribution and other regulatory constraints. Using the optimization model the optimal decision recommended is to transport conditioned gas by pipeline to a tidewater port for liquefaction and marketing to Pacific Rim countries. Two pipeline routes are considered feasible: the southern route that parallels the Trans Alaska Pipeline System (TAPS) to Valdez, Alaska, and a western route that would cross the National Petroleum Reserve in Alaska to a port either in Wainwright or Kivalina, both in Northwest Alaska. The advantages of the southern route compared to the western routes are presented.

This paper describes evaluation, design, static and dynamic field testing, and installation of a driven steel pipe pile foundation system in highly saline permafrost. Static load tests were conducted on two test piles as part of the final design to confirm and refine preliminary pile capacities. Dynamic pile tests were conducted on four production piles during construction to confirm pile drivability without pilot holes, assess hammer and pile performance, and confirm the results of the static load tests. These dynamic tests are believed to be among the first such tests run on driven piles in permafrost. The dynamic tests provide magnitude of steel stresses in the pile and allow assessments of the pile integrity during driving, thus providing a useful tool to avoid pile damage in permafrost conditions where unaided pile driving may be feasible. Comparison of the static and dynamic test results can aid evaluation of such factors as load distribution between the toe and the shaft, distribution of shaft load, residual and full adfreeze bond strengths, and short-term versus long-term soil strength.

The Kharyaga pipeline terminal was part of the first oil field development in Russia by an American-Russian joint venture after the breakup of the Soviet Union. The terminal for the pipeline was located in Kharyaga, a small settlement in Komi Republic. The U.S. partner was responsible for engineering the terminal and developing it using appropriate U.S. technology.

A research project co-sponsored by the U.S. Army Corps of Engineers, the Alaska Science and Technology Foundation, and the Alaska Department of Transportation and Public facilities to develop design criteria for geosynthetic capillary barriers is being conducted at the U.S. Army Cold Research and Engineering Laboratory. The successful use of geosynthetic capillary barriers would allow the use of a greater volume of frost-susceptible soil in roadway and airport embankments, while achieving the same or better pavement performance, resulting in great cost savings. The results of past work with granular capillary barriers in pavements to reduce frost heave provide preliminary guidance for using geosynthetic barriers.

In 1949 and 1950 the Presbyterian Church constructed a building at Savoonga, Alaska. Creosote-treated timber piles supported the building above grade. The piles extended 0.9 m below grade into permafrost soil. Space under the building was enclosed by skirting. So heat emitted through the building’s floor warmed its underlying air space and permafrost soil. Over the next 42 years the piles slowly settled, which caused distress to the building. The building was relevelled in 1975 and again in 1990 to adjust for the settlement.

A Triodetic Foundation was placed under a small house which had undergone serious distress due to thawing permafrost. The manufacturer’s specifications stated that the foundation would keep the structure on a plane within a tolerance of L/360 regardless of the magnitude or pattern of differential movement caused by future frost heaving or thawing permafrost. The house was placed on the foundation in June 1994. It was about 20 cm (8 in.) out of level, but nearly on a plane. In late September the foundation was levelled. During the levelling process it was obvious that the foundation was not as rigid as anticipated, hence the next summer (1995) the foundation was tested to evaluate its rigidity. The results show differential settlements in excess of L/50 under less than the most severe surface movement conditions.

A large area of the Northern hemisphere consists of soils which are permanently frozen. The top layer or active layer is subject to seasonal freezing and thawing. When building on this ever changing upper layer differential settlement is sure to occur. All efforts relating to the selection and installation of proper building materials such as insulation, double or triple glazed windows, arctic doors, sealants, heating and ventilating systems for the building can not be relied upon unless these are free of stresses induced by differential settlement of the building.

Constructed in 1994-1995, the 262 m West Dock Causeway Breach bridge is located along the West Dock gravel causeway in the Beaufort Sea on Alaska’s north slope. The bridge was designed by Peratrovich, Nottingham & Drage, Inc. (PN&D). The bridge was constructed in response to concerns of coastal shoreline fish movement and water circulation.

Since the late 1960's, drilling wastes, mostly muds and cuttings, have been generated as a result of developing Alaska’s North Slope oil fields. These materials have been stored in above ground reserve pits formed by constructing gravel berms on the tundra next to the gravel drill pad at each drill site. The tundra and underlying permafrost, which is about 550 m thick at Prudhoe Bay, served as a pit floor.

Aerobic soil microbes use oxygen as a terminal electron acceptor. Diffusion of atmospheric oxygen into tundra soil is hindered by the prevailing saturated conditions. Solid compounds that release molecular oxygen during breakdown were investigated as a source of oxygen for subsurface microbes during bioremediation of crude oil in tundra soils. Laboratory scale reactors containing tundra soil were incubated over a period of seventy-five days at 12°C. Reactors contained either sodium carbonate peroxyhydrate (Na₂CO₃•1.5H₂O₂) or calcium peroxide (CaO₂) buried in the lower half of a bi-layer soil bed. Periodic measurements of soil pH and total heterotrophic organisms were used to assess the relative effectiveness of each compound. Organism concentrations reached 6.3 x 10⁷ CFU/g dry soil and 6.3 x 10⁶ CFU/g dry soil in reactors containing sodium carbonate peroxyhydrate and calcium peroxide, respectively. These values compared to a background value of 2.5 x 10⁵ CFU/g dry soil. The concentration of organisms peaked after roughly 13 days of incubation in both reactors containing a peroxide. Although the organism concentrations fluctuated in these reactors, they generally remained above the background concentration during the entire 75 day incubation.

Air Force installations are wide spread in Alaska, ranging from Elmendorf Air Force Base (AFB) in Anchorage to Eielson AFB in Fairbanks to radar stations along the North Slope. The majority of these installations have environmental contamination from their 50 plus years of operations. By far the most pervasive types of contamination are from hydrocarbons. The Air Force has initiated several different cleanup technologies throughout the installations. This paper will focus on the cold regions engineering aspects of treatment technologies used at several sites. These sites include, but are not limited to, bioventing projects at Elmendorf AFB and a bioventing project at Eielson AFB.

The effects of cold environmental temperatures on the toxicity of inhaled vapours is explored by means of a literature search in order to determine what physiological parameters may be different in cold regions, followed by input of those physiological parameters into a physiologically-based pharmacokinetic model (PBPK) for vapour inhalation. The literature search provided sufficient quantitative information for estimates regarding increased ventilation rate and blood flow distribution during two types of cold temperature metabolic compensation, shivering and non-shivering thermogenesis. That information was input into a PBPK model for styrene, ether, ethanol, and methanol. The model indicated that the hydrophobic ether yields little increase in total systemic exposure at the higher ventilation rate. Styrene, ethanol and methanol had increased systemic exposure but the increase was not linear because of altered blood flow to the liver. In general, more vapours are absorbed in cold climates than in temperate climates. Qualitative data recovered from the literature indicated that liver function is disrupted in the cold, including shifts in enzymes and decreases in anti-oxidants. Oxygen free radical production is increased, with concomitant increases in lipid peroxidation. The conclusion is that vapours may be more toxic in colder than warmer climates, but the quantitative data for risk assessment is lacking.

Fairbanks, Alaska has a very dry climate. With less than twelve inches of moisture (snow and rain) per year, the large interior land mass which surrounds Fairbanks would be sandy desert but for the low average temperature. Maintenance of the recommended level of 25% to 60% relative humidity in buildings in Fairbanks is complicated by: 1) the dryness of fresh air used for ventilation, especially after the cold winter air is heated to room temperature; 2) limitations of materials for use in the construction of functional thermal and vapour envelopes; 3) knowledge of, and incentives for, the correct installation of those materials by workmen, and 4) knowledge of, and incentives for, the planning, design and maintenance of building components necessary for containment of the appropriate relative humidity.

There is no question that increasing thermal values of insulation and eliminating air leaks has reduced energy requirements of buildings. However, the improper selection and placement of the insulation, vapour barrier and lack of ventilation has resulted in costly legal action to repair condensation-related maintenance problems. Unfortunately, condensation problems do not become apparent for 5 to 10 years after construction, long after the one year warranty is null and void.

Sliding snow and ice can damage property, kill people and overload lower roofs. In valleys, moving snow can roll the standing seams onto their side, violating the waterproofing seals within them.

Beginning with the winter of 1990, several outdoor gas-fired heaters ranging in rating from 43,950 W (150,000 Btu/hr) to 11,720 W (40,000 Btu/hr) underwent testing in Fairbanks, Alaska. The manufacturer had experienced field problems with similar units in cold climates. The objectives of the testing program were the following: 1) instrument these units with an adequate number of thermocouples and record temperatures at critical locations of the units, 2) document their performance and identify signs of frosting at air intake louvers and at the inducer fan, 3) monitor the performance of the electronic circuit board that activates gas valves, blowers and other controls as the ambient temperature goes down in the winter months, and 4) record through photographs the problems encountered and any malfunction as the ambient temperature dips to subarctic levels.

The U.S. has occupied the geographic South Pole continuously since 1956 with the Amundsen-Scott Station. The planning and design for a third generation station is currently underway. This paper reviews the primary utility systems serving the existing facilities and discusses the systems proposed for the new station.

This tutorial paper describes cold-related electrical power system problems and suggests potential solutions, based upon a review of relevant literature and discussions with electric utility and utility equipment engineers located in several high-latitude countries. Although not directly attributable to cold climates, electric power quality and geomagnetically-induced current effects are also concerns of high-latitude electric power system designers and operators, and are discussed.

The vertical displacement of soil resulting from frost heave can cause significant damage to foundations and roads. Also detrimental is the related problem of instability due to the presence of excess water when the segregated ice in the soil mass thaws. A laboratory testing program was conducted to verify the suitability of an iron (II) amine complex compound (ACC) to serve as a stabilizer for roadway embankment soils against frost heave and thaw weakening. Specifically, the frost heave and thaw weakening response of a soil from Homer, Alaska, was monitored with concentrations of ACC varying from 0.0 to 3.0%. The frost heave was evaluated with the segregation potential concept, and the thaw weakening was evaluated with a measurement of resilient modulus. It was observed that the addition of small amounts of ACC greatly reduced the segregation potential of the test soil. After one freeze-thaw cycle, a slight increase in the resilient modulus of the test soil was observed with the addition of small quantities of ACC.

The Cone Penetration Test (CPT) has been used as a logging tool in cold regions engineering to define the spatial distribution of permafrost and degree of ice bonding in soil. It is also a useful design tool for determining the in situ creep parameters of frozen soils. The creep settlement and bearing capacity of permafrost under a deep circular load can be predicted from an appropriate procedure and an interpretation based on the model of an expanding spherical cavity in a viscoelastic-plastic medium.

A reliable method of measuring soil thermal resistivity using the thermal probe is presented. A field and laboratory survey of 100 Canadian soils was used to compile a thermal properties database. The soils were grouped according to the Unified Soil Classification System (modified) and the thermal dryout curve (thermal resistivity versus moisture content) envelopes defined. Although the thermal dryout curve for a given soil may be placed within a specified envelope, its exact shape and position are determined by other parameters (i.e. dry density, organics, mineral composition, particle shape, fines content, etc.) and their complex inter-relationship. The influence of ambient temperature on the thermal resistivity was investigated. For wet soils above 0°C, resistivity decreases as temperature increases; at 0°C there is a dramatic reduction (20 to 40%) in the resistivity; below 0°C resistivity decreases as temperature decreases.

This paper presents the results of high-pressure triaxial compression tests on dense Manchester Fine Sand (MFS) in both frozen and unfrozen states. Frozen sand specimens consisted of pre-formed and consolidated-then-frozen specimens. Unfrozen, isotropically-consolidated undrained (CIUC) or drained (CIDC) tests were also performed. Special testing procedures allowed accurate measurement of specimen load-deformation behaviour from small (0.001%) to very large (20%) axial strains.

In general, frozen MFS tests exhibited substantially higher moduli, upper yield stresses and peak strengths than unfrozen tests performed under similar conditions. In addition, the modulus and upper yield stress for unfrozen MFS is strongly dependent on the effective confining pressure (s’_c) while the modulus and upper yield stress for frozen MFS is independent of s’_c. The post upper yield stress-strain behaviour (e_a greater than »2%) is strongly affected by the level of confinement for both frozen and unfrozen tests.

This paper describes the results of a 1995 water quality sampling program in 10 water sources used by Native villages across Alaska’s Arctic Coastal Plain, conducted by Northern Testing Laboratories, Inc. (NTL) of Fairbanks, Alaska. The focus is on the parasitic protozoans Giardia lamblia and Cryptosporidium parvum. Giardia is currently one of the definitive organisms in the Surface Water Treatment Rule, incorporated into the State of Alaska Drinking Water Regulations (18 AAC 80, May, 1994). At least one or both of these microorganisms were detected in each of the ten water sources during one or more rounds of sampling. Overall, eight of the sources had Giardia lamblia and eight had Cryptosporidium ssp. This is a significant treatment concern for rural Alaskan villages.

In September 1992, the Nome Joint Utility System (NJUS) took ownership of a two celled sewage lagoon. The Wastewater Treatment Facility (WTF) was designed as a sludge holding facility and primary sewage treatment for the City of Nome.

This paper describes the failure of a lined wastewater treatment lagoon in a south central Alaska community. Its objective is to provide valuable insights regarding key design and performance issues for all designers of such facilities in cold region areas. The treatment plant, including a lined aerated lagoon, was placed into service in 1982. The 114 million-litre (30 million gallon) lagoon was lined with 1.1 millimetre (45 mil) reinforced chlorinated polyethylene (CPER). The lagoon liner system failed in August 1991, allowing sewage effluent to escape into the ground. The failure included development of large bubbles below the liner, rupturing of air piping, and formation of large tears in the liner. This paper describes evaluation of the most likely failure mechanisms and development of a repair scheme for the lagoon that minimizes the potential for these failure mechanisms to reoccur. Possible failure mechanisms include gas formation below the liner, development of air pockets below the liner from fluctuating groundwater levels, liner damage by abrasion from concrete anchor blocks, liner damage from oversize bedding material, liner damage by wind-driven ice, and other factors. Design features of the new liner system, including liner type, are described. The remedial design included a two-cell lagoon that would allow one cell to be drawn down for maintenance and repair without putting the entire lagoon out of service.

In the process of biological removal of nutrients (N and P) from wastewater, low temperatures affect primarily the rates of nitrification reactions. Biological phosphorus removal (BPR) is less influenced by low temperature and if the source of short chain volatile acids (SCVFA) is readily available, the process would be efficient at wastewater temperatures below 5°C. Sidestream production of SCVFA from primary sludge, however is required in continuous flow processes. Prefermentation of the whole wastewater may be necessary to enhance BPR for smaller plants utilizing the sequencing batch reactor (SBR) concept.

Successful operation of drinking water facilities requires monitoring of water quality parameters to provide the information necessary for process control. The drinking water quality reporting required by authorities in Alberta for small communities involves the analysis of one sample per day. For most small communities this is the extent of their entire sampling regime. It is questionable whether a single sample per day is adequate to provide the required information for the operator to achieve control of the treatment process and assess overall drinking water quality. Small remote communities have another complicating factor in that the operators are more isolated from technical support. A possible solution to these difficulties is remote water quality monitoring which will essentially provide continuous monitoring and technical support to help resolve problem situations.

Eight saline water wells were drilled within the Alaska Native community of Deering for use as toilet flushing water. The wells successfully located a brine water source below permafrost ranging in depth from 30 to 91 feet (9.1 to 27.7 m). Pumps were set in four of the wells and plumbing installed to provide the brine water to toilets in three homes and the community building. The systems have now successfully operated for 18 months.

The heightened public awareness of environmental issues has brought with it increased public concern with drinking water quality. All communities are faced with meeting higher water quality standards with aging facilities and limits to fiscal resources, but it is the smallest communities that face the greatest challenge.

A three-dimensional discrete element model coupled with a one-dimensional depth-averaged usteady hydraulic model is used to simulate river ice jam formation. Ice runs are arrested by an ice control structure consisting of cylinders spaced across a channel. This type of structure is typically constructed in small, relatively steep rivers to cause temporary ice jams in areas where flooding is not a problem, to protect downstream areas where recurrent flooding is a serious problem. The three-dimensional discrete element simulation consists of several thousand floes. Each floe is a flat circular disk with arbitrary diameter and thickness. Feedback between ice floes and water is through water drag on floes and partial blockage of the channel by floes. The simulations begin by releasing a large concentration of ice floes upstream of the structure at the flow velocity. As the ice floes move downstream, collisions between neighbouring floes and collisions between floes and the channel bottom and ice control structure are explicitly modelled. An ice jam is initiated by arching of floes between the control structures. The momentum of colliding floes and water drag cause the jam to thicken. The arrival of additional ice causes the jam to progress upstream. Concurrently, the ice forces on the structure are determined.

Field observations have indicated the probability of violent ice runs with extremely high water velocities and rapid water level rises following the release of major ice jams. A complete quantitative description of such an event does not exist due to the difficulties in collecting data on water and ice movements in the field. In this paper, an analytical formulation for ice jam release is presented. A two-dimensional numerical model is developed and used to provide a better understanding on the dynamics of ice jam release.

Considerable debate surrounds the evaluation of boundary roughness and, thereby, flow resistance in ice-covered channels. The debate revolves around how to characterize and combine the influences, on flow resistance, of bed and ice-cover roughnesses. The highly variable nature of boundary roughness and the empirical framework of all resistance relationships amplify the debate. The present paper addresses the debate and suggests it is time to move on from the customary use resistance equations (for example, the Sabaneev equation) based on Manning coefficients.

Communities located on small, northern rivers can experience severe breakup ice jams. While flood damages may be significant locally, they are often too low to justify conventional flood-control structure. Environmental concerns also tend to render these structures unattractive. We have developed a new, low-cost structure to control breakup ice jams on small rivers. It consists of massive sloped blocks, partially buried in riprap, placed across the river adjacent to a natural floodplain. The blocks will arrest a breakup ice run and form a stable, partially grounded ice jam. Trees or boulders on the floodplain retain ice pieces in the river channel while allowing flow to bypass the structure. Large gaps between blocks allow easy fish and canoe passage. Part 1 of this paper describes the development of this concept, and Part 2 describes its full-scale performance.

Hardwick, Vermont, on the Lamoille River, has experienced 10 ice-jam floods in the past 30 years, yet damages are insufficient to justify conventional flood-control measures. We constructed a new ice-control structure (ICS) in Hardwick, in partnership with the Town and the Federal Emergency Management Agency, to assess its potential to control breakup ice jams. It consists of four massive, slope-faced granite blocks, spaced across a 27 m wide river section adjacent to a treed floodplain, and cost $100,000, exclusive of land and design costs. We instrumented the site with pressure transducers and a video camera to record the performance of the new structure. The ICS experienced two mild breakup events during its first year of operation and held an ice jam for several hours during the more severe one. No flooding occurred downstream during these events. The field performance of the structure was similar to hydraulic model results for cases of thin, weak ice.

The Shakwak project in the northwestern Yukon involves the reconstruction of over 500 kilometres of highways located in the discontinuous permafrost zone.

With freezing indices ranging from 800 to over 2,000 °C•day and frost penetration reaching up to 3 metres under pavement surface, frost action has always been a major concern for pavement engineers in the province of Québec (Canada). This paper presents alternative techniques to protect pavement against the detrimental effects of frost action. Field observations over the first freeze-thaw cycle of highway sections insulated respectively with saw dust, a sand/tire chips mixture and extruded polystyrene are presented. The instrumentation consisted of heave gauges, thermistors, TDR probes, piezometers. Falling Weight Deflectometer tests were also performed in fall to determine the mechanical characteristics of each test section. The data suggest that the test section insulated with saw dust performed well and had the best cost-performance ratio. The test section with styrofoam also performed well. The sand/tire chips layer did not prevent the frost from penetrating into the frost-susceptible subgrade. The field results of the control section were analyzed with FROST1D using the segregation potential. Predictions and observations were agreed well confirming the relevance of the SP-based approach for frost heave prediction in the field.

Snow and ice conditions have been considered the main factors that contribute to reduced vehicle traction forces and potential traffic accidents during winter seasons. To increase vehicle’s traction forces on snow and icy surfaces, studded and non-studded winter tires have been used in cold regions. However, the use of studded tires causes significant pavement damage, such accelerated pavement rutting and pavement marking damage. Since the spring 1994, the Alaska Department of Transportation and Public Facilities has requested the Transportation Research Center at the University of Alaska Fairbanks to conduct several research studies related to vehicle traction performance on snow and icy surfaces in Alaska. The study summarized in this paper concentrated on the following aspects:

In June of 1995, engineers for the Alaska Department of Transportation and Public Facilities journeyed to Norway, Sweden and Finland to investigate Scandinavian research into reducing the effects of studded tires on pavements. Many northern tier states in the United States have banned studded tires; since the 1970's, little research has been done in North America. The road administrations, road institutes, and tire manufacturers of Norway, Sweden and Finland have continued to do extensive research on studded tires. To solve the problem of stud damage to pavements the three countries researched stud design, tire traction, driver behaviour, aggregates, asphalt concrete, and asphalt mix designs. The solution to studded tire wear involved a three pronged approach. First, the countries legislated the use of lightweight studs: studs that weigh less than 1.1 grams. The core of the stud is tungsten carbide steel, but the lightweight sleeve is either plastic or aluminum oxide. This stud reduced pavement wear rates by 50 percent. Second, they used a Stone Mastic Asphalt (SMA) concrete mix for surface courses. This mix contains up to 70 percent coarse aggregate. The use of SMA can reduce pavement wear rates from 25 to 50 percent. Third, they found hard durable aggregates that resist studded tire wear better than aggregates from local material sources. They developed tests such as the Ball Mill Test, SRK Test and the Point Load Test. Their research showed that the commonly used wear and degradation tests do not correlate to pavement wear due to studded tires. The harder aggregates that resist studded tire wear are fine grained metamorphic and volcanic rocks and make up only 2 to 4 percent of the rock in Scandinavia. They have hauled this rock up to 300 kilometres for a wearing course. The use of these harder aggregates can reduce wear rates by a factor of three to five compared to using local aggregates.

Deformations of roadbeds on permafrost soils are due to permafrost degradation in the roadbed base. The principal measures used to ensure roadbed stability on weak bases or those subsiding under thawing usually are the following: making a reserve by the embankment width and height, placing the roadbed on the ballast, constructing forms, filing the embankment with rock, and cutting out ice-saturated bed soils and replacing them with a draining material compacted layer-by-layer, among others. These measures are essentially of a passive or reactive nature; they are aimed primarily at overcoming the consequences of existing permafrost degradation, they require expensive road construction and maintenance, and they do not solve the problem by ensuring roadbed stability on very icy permafrost.

In northern Quebec, where the average freezing index is 3,500°C•$day, permafrost conditions within an homogeneous earth-structure were noticed after several years of operation. Temperature evolution during one freeze-thaw cycle were automatically monitored during 1994-1995 as well as deformations of the downstream face and pore pressures at various locations. Permafrost conditions between 4 and 6 m below the crest and between 2 and 8 m in the downstream shoulder were observed in 1994-1995, i.e. after 12 years of operation. However, in the downstream toe area only a thin permafrost layer was detected owing to snow conditions and possibly advective heat flow from seepage through the drain. The average temperature of the permafrost zone was about -0.2°C. Downstream slope movements are induced by in situ pore expansion as the active layer freezes, leading thus to a solifluction deformation process. Finally, it appears that the horizontal drain remains operative despite the presence of permafrost.

The cost effective remediation of an active landslide of coal mine spoils at Usibelli Coal Mine (UCM) near Healy, Alaska presented several geotechnical challenges. The slide currently encompasses approximately 37 hectares and has an estimated slide volume of approximately 4,000,000 cubic metres. The slide mass has a well documented history of seasonal movement with velocities as high as 13 cm/day. Despite these constraints, a stabilization method to address Poker Flats outslope conditions has been proposed. Primary tasks include the construction of surface water diversions, buttressing at the toe of the spoils, regrading of the headscarp areas, installation of nested piezometers with data collectors, and revegetation. Long term plans include the construction of a full toe drain and contingency plans for upgrading the buttress in subsequent years.

In the Hetao Irrigation Area, Inner Mongolia Autonomous Region, China, canal irrigation has a very important effect on the agriculture. The climate is very cold and dry in winter. The problem of frost action damage is widespread in hydraulic construction in the area. This paper presents full-scale test studies on prevention of frost damage for a 2 m high retaining wall reinforced with geotextile. The facing panel was made up of reinforced light precast concrete slab. The horizontal displacement of the facing panel, the strain of geotextile, and the soil temperature and moisture content were measured during the winter of 1993-1994 (the Frost Index FI=837°C day). Steel wires were used to measure geotextile strains in the retaining wall under winter conditions. The test results indicated that the displacement of the facing panel comprises of horizontal frost heave and unfrozen-soil compressive deformation of backfill. In the 0-0.3 m range near the facing panel frost heave occurred. In about the 0.3-0.9 m range from the facing panel the soil was compressed before freezing and heaved after freezing. Outside that zone the soil was compressed. The horizontal frost heave of backfill was 15-30 mm, while the horizontal displacement of the facing panel measured only 6 mm because the frost heave was partially counteracted by the compressive deformation of back unfrozen soil. Near the facing panel, the frozen soil formed a thick solid mass with great rigidity and strength and was approximately equivalent to a pseudo gravity retaining wall which resisted the frost heaving action of back soil.

The concept of design and construction of an earth dam with a permanently frozen core as a seepage barrier is not new for permafrost areas. This paper describes thermal analysis simulating various construction scenarios in order to obtain the initial temperature distribution within the earthfill dam as a function of design variables, such as climate, rate of fill placement, thickness of earth lift, placement temperature and ground temperature. The study showed that lift thickness and climate were the most important factors controlling temperature distribution in the core.

Freezing and thawing cycles may deteriorate the permeability of the liner or cap. One dimensional freezing tests are conducted in the laboratory using a frost measurement system to determine the temperature and time required to freeze slabs of paper sludge and clay used as landfill covers. Freezing of the material did occur, since soil resistivity increased steadily as the temperature decreased.

Although freezing dramatically alters alum sludge flocs such that they dewater more readily, a fundamental understanding of this phenomenon is needed before widespread application is possible. In an attempt to do this, the ice/water interface in alum sludge was investigated using a microscope-mounted freezing stage. Using a 10x objective, the interaction of sludge flocs with the advancing interface was watched in detail. The dependence of floc behaviour on freezing rates, or interface velocities, were noted. Also, available models on particle/interface interaction were assessed.

Implementation of modern solid waste management practices in rural Alaska is problematic for a variety of reasons including the remoteness, lack of transportation, the severe climate, frequent lack of funding, limited opportunities for recycling, and presence of bears, to name a few. Cultural factors also enter into the picture.

A Municipal Solid Waste (MSW) characterization study was conducted in Fairbanks from May 1995 to April 1996. This study involved sampling, sorting and weighing the individual components of the waste stream. The sorted unprocessed MSW was analyzed using standard test methods of the American Society for Testing and Materials (ASTM). Properties such as bulk density, thermal characteristics (moisture content, non-combustible and combustible fractions), and gross calorific value (by oxygen bomb calorimetry) of each waste component was determined. Results show notable differences between Fairbanks waste generation and national averages that provide insight into the unique domestic and commercial waste-generating activities in a cold, remote region. Valuable data from the characterization study will be used to set waste management goals and track progress toward achieving those goals, that will yield economic benefits and increase landfill life in Fairbanks, Alaska.

During the winter 1994-1995 season, chassis dynamometer tests were conducted to assess the effect of different fuel types on automobile emissions under arctic conditions. Tests and measurements were conducted according to standard Environmental Protection Agency guidelines as cited in 40 CFR 86. The fuels chosen were regular unleaded gasoline and the same fuel with a 10 percent substitution by volume of ethanol (E-10). Ten vehicles, statistically representative of the Fairbanks automobile fleet, were tested at ambient temperatures of 20°F and 0°F. Chemical species monitored in tailpipe emissions included carbon monoxide (CO), carbon dioxide (CO₂), oxides of nitrogen (NO_x), and total hydrocarbons (THC).

Cominco Alaska, is one of the largest zinc/lead mines in North America. The ore body is mined as an open pit. The ore is blasted and hauled to the nearby mill complex. At the mill, the ore is crushed and milled to a fine powder, then metal sulfides are concentrated in flotation cells. Floats from the cells are dewatered in filter presses. The filter cake is the metal concentrate.

Sanitary waste disposal problems in rural Alaska contribute to the high incidence of endemic enteric and other diseases experienced by people living in rural communities. These diseases include hepatitis, impetigo and others. More than 20,000 Alaskans use honeybuckets. It is widely accepted that the use of honeybuckets as a means of disposing of sanitary waste contributes to the disease problem. Mitigation of the problem is focused on finding more sanitary means of disposing of sanitary wastes. The long term goal of the Indian Health Service (IHS) is to install piped water and sewer in each community. An analysis of the cost data at the Public Health Service (PHS) indicates that a sanitary sewer line averages $60,000/household in rural Alaska. Interim measures have been developed to reduce human contact with the wastes. These measures include derivatives of honeybucket systems, community haul systems, and others. One possible disposal technique is incineration of the waste within each residence by using combustion toilets. Combustion toilets eliminate handling of sanitary wastes. This project involved the testing of a Storburn Combustion toilet. The Storburn toilet incinerates waste at 300°C using propane. Testing included monitoring of the exhaust stack temperature during combustion. Based on a five year useful life, tests indicate that for three adults, the toilet can be operated for $1,756 annually.

A physically-based constitutive model is presented for the ductile and semi-brittle region of polycrystalline ice. The capability of the model in dealing with complicated behaviour of ice is first described. Constants of the model are then estimated from existing experimental data. Results for creep for the ductile and semi-brittle regions predicted from the model are then compared with the experiments. Important future experiments needed to further develop the model are then described.

The paper consists of excerpts and passages from a longer unpublished 1993 manuscript entitled "Wortley’s Winter Wanderings: Reminiscences of an Iceman Who Cameth and Wenteth in the Great Lakes . . . narrative report to the University of Wisconsin Sea Grant Institute and others who may have wondered what I have been doing. ." Copies of the complete manuscript are available from the author. This paper describes some of my activities and observations over a period of 16 winters in the US and Canadian Great Lakes small-craft harbours.

Spaceborne synthetic aperture radar (SAR) images are used to identify and differentiate between lakes that freeze completely to the bottom and those that do not in two areas of the North Slope in N.W. Alaska. At Barrow, on the coast of the Arctic Ocean, 60% of the lakes freeze completely to the bottom in mid-January alone and by the end of winter 77% of the lakes are completely frozen to the bottom. In contrast, 100 km to the south in the "B" Lake region, only 23% of the lakes freeze completely to the bottom and there is no sudden freezing of many lakes as occurs at Barrow. A physically based, numerical model is used to simulate ice growth on the lakes. The simulated maximum ice thickness is 2.2 m. Any lake where some part of the ice cover does not freeze to the bottom thus has some water >2.2 m deep. For those lakes where the ice cover froze completely at some time in the winter, the simulated ice growth curve provides the ice thickness at the time each lake froze completely to the bottom and thus maximum water depth. At Barrow, 60% of the lakes are up to 1.4 m/1.5 m deep and 25% are >2.2 m deep. At the "B" Lakes, 75% of the lakes are >2.2 m deep. Thus, there is a considerable contrast in lake depth and water availability between the Barrow and the "B" Lakes regions. This method is simple to implement, and the SAR data are relatively inexpensive and have sufficient spatial and temporal coverage; thus it could be used to determine lake depth and water availability on the entire North Slope and in other polar and sub-polar areas where shallow lakes are common.

Paving in cold climate, particularly in permafrost areas, requires special technical and engineering considerations. This is because under such conditions not only the properties of asphalt concrete at low temperature but also thaw settlement and frost heaving distresses have to be considered in pavement design, construction and maintenance. This paper first presents a general description of the Qinghai-Tibet Plateau Highway, which is the highest highway in the world in terms of elevation. It then discusses the main factors causing pavement surface distresses such as thaw settlement and frost heaving of the pavements in this permafrost region, and finally presents a practical assessment of asphalt pavement design, construction, maintenance and performance prediction. The case study includes: variation analysis of the upper boundary of the permafrost table movement under seasonally changeable environmental conditions, discussion of pavement distresses based on the observed data and field experiments taken from the case study, and evaluation of some empirical methods used for the determination of pavement thaw settlement and frost heaving in this particular permafrost area.

Open Graded Bases (OGB) and Rapid Draining Material (RDM) to promote horizontal drainage of water from pavement systems have not been used extensively in the United States until recently. Drainage layers are now required beneath most Army and Air Force pavements, whether rigid or flexible. To assess the effectiveness of an OGB within a flexible pavement in areas of seasonal freezing and to ultimately evaluate the optimum OGB location within a pavement structure, three test sections with an OGB layer at different depths within the pavement structure were constructed on a USDA Forest Service Road in Berlin, NH. The sections were monitored for surface and subsurface temperature, moisture content, frost heave, pavement stiffness, and meltwater (water introduced by freeze-thaw cycles) collected in the drainage layer. Compilation of field data from these sections constitutes the first in a series of steps to determine the optimum location within a pavement system (in areas of seasonal frost) for OGB placement. This paper discusses drainage test section design, construction, instrumentation, observations to date, and overall strategy for determining the optimal OGB location.

Frost heaving of roads is one of the reasons causing pavement damage in cold regions. In this paper, an approach to the design of pavement structures on frost-susceptible subgrades is presented. The frost susceptibility is described by segregation potential of the freezing subgrade. Design charts are presented both for mineral embankments and for insulated embankments. The thickness of the non frost-susceptible pavement structure or the necessary thermal resistance of the frost insulation can be determined as a function of the desired frost heave level and freezing index of the location at two degrees of frost susceptibility (segregation potential) of the subgrade. This design approach has been applied in the design of streets and car-parks in Finland from the late 80's.

In cold regions, the orientation and timing of movements along longitudinal pavement cracks are direct functions of two general conditions; seasonal frost action and/or thaw-unstable permafrost foundations. Each category can be characterized by different crack patterns, magnitudes and rates of movement, and boundary processes. Understanding these differences are prerequisites to designing economical new embankments or repairs. Simplified models are presented to qualify the potential boundary processes causing longitudinal cracks in cold regions. A limited review of techniques for mitigating this type cracking is also provided.

In 1979 the field research project "Economical Concrete Pavements" was started. This main project was administrated by the Norwegian Road Research Laboratory and during the following years it involved several projects throughout the country. The goal with the project was to get reliable information in order to determine where and how to use concrete road pavements.

In 1989 the authors of this paper were asked by the Municipality of Anchorage, Alaska (MOA) to conduct a study to determine why some of the recently completed pavements in the Municipality were showing signs of significant distress and cracking. Later in 1992, a follow up study was conducted. Since that time many of the original recommendations have been implemented by the Municipality and the results of these implementations have been monitored. This paper will summarize the findings of the two studies and will report on the performance of some of the pavements which have incorporated the recommendations presented in the two reports.

Bituminous Surface Treatments (BSTs) have been used in Northwestern British Columbia and the Yukon for the past 15 years. The area is characterized by remote locations with a harsh climate, bog and fen complexes and permafrost.