The Arctic Coastal Plain may seem to be abundant in water resources, but in actuality, the low precipitation limits the amount of readily available water. Much of the available water resources come from snow melt, runoff, and rivers and lakes within the area. In arctic and subarctic areas, rivers typically carry 55 to 65 percent of precipitation falling onto their watersheds. The reason is that permafrost prevents the downward percolation of water and forces it to run off at and very near the ground surface. One of the consequences of the high runoff is that northern streams are much more prone to flooding. Another is that they have higher eroding and silt-carrying capabilities (A). 

Critical to the control of water runoff in the north is the cover of moss and other vegetation of the tundra, bogs and forests. A thick layer of moss acts much like a sponge laid over the permafrost to slow down the movement of water across the ground surface.

One main source of water is in thermokarsts or thaw lakes. These lakes are actually thaw basins, low areas in the tundra where water from melting snow and ice collect. Thousands of square miles in the Arctic are covered by ground which has been segmented into what are called tundra polygons or ice wedge polygons. This pattern is caused by intersecting honeycomb networks of shallow troughs underlain by more or less vertical ice wedges. The ice wedges are formed when the ground contracts and splits in a manner analogous to the formation of cracks on the dry lake bed. This allows water to enter, and successive seasons of repeated partial thawing, injection of water, and refreezing cause the wedges to grow. As they do, the strata to either side are turned up to enclose the polygon, and a lake may form in the center with the raised troughs at the margins.  Above the frozen region, unfrozen water saturation increases due to low hydraulic conductivity, which prevents the melting ice from draining, thus causing accumulation of water above it (E). During this process, pingos are sometimes formed, when the pressure from the contraction of the unfrozen water pushes it up until it collects and freezes under the root mat.

All of the thaw lakes studied were very shallow; even though the lakes could be several thousand feet long, most were no deeper than 10 feet (A).

Drainage patterns typically follow the troughs, and where they meet, small pools may form. These are often joined by a stream which causes the pools to resemble beads on a string -- in fact, this type of stream form is called beaded drainage. Thaw lakes tend to be elongated perpendicular to prevailing winds caused by subsurface currents. The waves caused by crosswinds may be eating away at the peat more aggressively along the edges creating a pattern of elongation that all arctic lakes share (A).

The amount of available water in the 1002 area has been estimated to be around 9 billion gallons (TAPS).

Water resources are limited in the 1002 Area.  In winter, only about nine million gallons of liquid water may be available in the entire 1002 Area, which is enough to freeze into and maintain only 10 miles of ice roads.  Although such exploration is conducted only in winter, snow cover on the 1002 Area is often shallow and uneven, providing little protection for sensitive tundra vegetation and soils. The impact from seismic vehicles and lines depends on the type of vegetation, texture and ice content of the soil, the surface shape, snow depth, and type of vehicle. 

Oil companies are withdrawing surface water faster than it can be replenished, says Steve Lyons, hydrologist with the U.S. Fish and Wildlife Service (USFWS). When an ice road melts, the water runs over the surface into streams, usually outside the original watershed from which it was withdrawn, he explains. Because the 1000-ft-thick permafrost does not allow groundwater movement between water bodies, lakes are filled only by snowmelt and may take more than two years to refill after the permitted 15% of their liquid volume is withdrawn for ice road construction (G).

Surface water will also be used for potable purposes at manned facilities, equipment washing, tank cleaning, dust abatement on roads and workpads, and hydrostatic testing.

Examining the soil and water cycles of the 1002 region, one cannot ignore the presence of permafrost, or “permanently frozen soil,” which underlies 80% of Alaska and remains a central issue in the debate about oil drilling. Permafrost has been defined as frozen ground in which a naturally occurring temperature below 0° C (32° F) has existed for two or more years (A). On the North Slope, permafrost ranges in thickness from about 700 to as much as 2,240 feet thick, and may be as cold as -8° to -10° C.

Permafrost can be either thaw-stable or non thaw-stable, depending on the type and percentage water of the soil it is made of. Permafrosts in more fine-grained soils like loess (silty) tend to thaw, sink, and create thermokarsts more often. Permafrost thaws from heat input, such as global warming or human activity, as well as the clearing of vegetation which insulates the ground.

      Permafrost is affected by road dust generated by traffic on unpaved roads; snow melt due to dust deposition can lead to flooding, ponding, and hydrological changes in oil. Continuing oil and gas exploration, development, and production, construction of a natural gas pipeline, the operation and maintenance of facilities, and other activities requiring road travel would add cumulatively to the volume of road dust generated on unpaved roads (A).  Regions of ice which have been wind-dusted are likely to undergo localized melting earlier than the neighboring non-dusted ice (A).

There are three approaches to dealing with the permafrost problem in the construction practice. The first and most obvious is to avoid it entirely. The second is to destroy it by stripping the insulating vegetative cover and allowing it to melt over a period of years. This has the obvious drawback of requiring a considerable period of time to elapse before construction can begin, and even then, it is a good idea to excavate the thawed ground and replace it with coarse material.

The third approach, and one which is becoming more widespread, is to preserve it. This can be accomplished by building on piles to allow cold air to circulate beneath heated structures, by building up the construction site with gravel fill which insulates and protects the permafrost below, or by refrigeration to maintain low ground temperatures. This is done by utilizing thermal piles or freeze tubes, such as those used by the trans-Alaska pipeline. These devices are filled with a non-freezing liquid and act like coffee percolators. They are cooled during the winter months and draw heat from the ground to retard thawing during warm weather (A).

In nearshore areas, ice-bonded permafrost is probably present and must be considered in the design of an offshore pipeline. But nearshore ice-wedge permafrost under shallow water, particularly along a rapidly receding coastline, is even more critical for design. Oil pipelines placed in areas of ice-bonded or ice-wedge permafrost must be heavily insulated to limit thawing of permafrost. The best location for an offshore platform is at water depths of 6.5-65 feet, to minimize ice gouging. Beyond the 6.5 foot water depth the top of the ice-bonded permafrost generally is below the surface of the seabed. Inshore of the 18-foot bottom-depth contour, ice gouging is typically less than 1.6 feet (Y).