The Colville River Delta is the largest river delta on Alaska?s North Slope. The Colville River drains much of the western and central arctic north of the Brooks Range, including the Killik, Chandler, Anaktuvuk, Nanushuk, Itkillik, and Etivluk Rivers. Ecologically, the delta extends west to also include the Fish Creek, Tingmeachsiavik, and Kalilpik River outlets into Harrison Bay. The delta is a rich and diverse breeding ground and staging area for waterfowl, shorebirds, and raptors. The delta also hosts caribou from the Teshekpuk Lake and Central Arctic herds throughout the year, as well as populations of musk oxen, moose, gray wolf, and grizzly bear, and provides important habitat for 22 fish species, particularly wintering Arctic cisco. A few small settlements exist in the delta (including some seasonal sites), the largest of which is Nuiqsut, a native village of around 500 people, as well as the Alpine Facility, an oil exploration site and oil pipeline connecting to Prudhoe Bay to the east.
The Colville River Delta and the adjacent Fish Creek, Tingmeachsiavik, and Kalilpik rivers are of major importance for breeding and staging waterfowl, shorebirds, and raptors. A total of 68 species regularly breed in the delta, with another 6 using the area at other times of the year. The delta is of particular importance to 3 species of waterbirds (Black Brant, Spectacled Eider, and Yellow-billed Loon) and 2 shorebirds (American Golden-Plover, and Stilt Sandpiper).
The Spectacled Eider was recognized as Threatened in 1993, due to drastic declines across its North American range . The Colville River Delta hosted an estimated 92 Spectacled Eiders during the Arctic Coastal Plain Survey of 2003. The majority of the eiders nested in the northwestern portion of the outer Colville Delta, although they have historically nested more extensively across the area. Numbers of Spectacled Eiders in the northeastern portion of the delta declined by 90% between 1987 and the mid-1990s . Despite the decline, however, the estimated number of Spectacled Eiders present still represents a significant portion of their North American breeding population.
The Colville River Delta is the site of the largest breeding colony for Brant on the Arctic Coastal Plain . The colony is located on the Anachlik Island complex in the northeastern portion of the delta. Annual counts of nests in the complex have been completed annually since 1994, with a minimum count of 700 nests (1994) and a maximum of 1400+ (2005) . Further counts during the brood-rearing period have found 6000+ birds on the water in Harrison Bay . These counts represent nearly 5% of the Pacific population of Brant.
The area with the second highest density of breeding Yellow-billed Loons on the Arctic Coastal Plain is located just to the northwest of the delta near the inlet of Kogru River into Harrison Bay, with slightly lower density breeding areas extending south and east from that region into the Colville delta. In the Kogru Inlet region, nesting densities were estimated at between 0.210 and 0.310 birds/km2 during the period 1998-2001 . Another area of moderately high nesting densities was found in the extreme southeastern portion of the delta region, where densities ranged from 0.110-0.210 birds/km2. Slightly lower densities, 0.010-0.110 birds/km2, were also found in a large portion of the central delta . Surveys undertaken in 1983-1984 and 1989 found 25-29 pairs in this same area of the core delta . The combination of these high-density areas generated an estimate of 296 adults in the entire Alpine Satellite Development Plan Area, of which the Colville delta comprises some 80% . That estimate is equivalent to roughly 10% of the entire estimated Coastal Plain population and over 2% of the estimated global population, and the 25-29 pairs found in the core delta is well over the threshold for a continentally important population.
The Colville River Delta also supports 20 species of breeding shorebirds, including continentally important concentrations of Stilt Sandpiper and American Golden-Plover, and lesser concentrations of sensitive species such as Buff-breasted Sandpiper, Whimbrel, and Bar-tailed Godwit [1, 4, 8]. For American Golden-Plovers and Stilt Sandpipers, nesting densities in the western part of the delta ranged from 0.743-2.214 and 0.233-2.385 pairs/km2, respectively . In the fall, the delta serves as an important staging site for post-breeding shorebirds, hosting an estimated 40,000+ individuals of 18 species. Among those shorebirds are continentally important numbers of American Golden-Plovers and Stilt Sandpipers, which have estimated seasonal totals of 410 and 1230 individuals respectively [3, 4, 5].
The major threat to the Colville River Delta is posed by the proposed expansion of the Alpine Facility to include five more satellite drilling installations (in addition to the existing two) and the associated infrastructure, such as roads, bridges, pipelines etc. In addition to the inherent destruction of habitat involved with increasing the oil development footprint in the delta, there will be an increased likelihood of an oil spill or other type of chemical pollution as well as an increase in the level of disturbance to breeding birds due to traffic of planes, helicopters, and other forms of transportation. Lesser threats center around pollution - the continued presence of elevated levels of lead and organochlorines in the blood of waterfowl, particularly Long-tailed Ducks; and, in the long term, the loss of tundra habitat as global warming causes 1) the spread of woody vegetation north into the delta, and 2) the rise of water levels, possibly flooding important barrier island nesting areas.
The western portion of the Colville River Delta, which includes the Fish and Judy Creek drainages, is owned and managed by the Bureau of Land Management as the National Petroleum Reserve - Alaska. Much of the eastern delta is owned by private groups - mainly the Kuukpik Native Corporation and a few individuals, including the Helmerick family. The rest of the eastern delta is owned by the State of Alaska and is managed by the Department of Natural Resources.
The Colville River Delta encompasses a wide variety of habitats, ranging from the shallow inshore waters of Harrison Bay to the upland shrub tundra that characterizes that southern portion of the delta area. Three habitat types predominate: wet meadows, moist tussock tundra, and freshwater lakes of varying depths and size. Amongst the variety of habitats present, a number stand out for their importance to birds, both for nesting and feeding. For waterfowl and loons, the most important habitats are open water with islands of polygonized margins, aquatic sedge with deep polygons, and patterned wet meadows. Shorebirds use a wider variety of habitats than do waterfowl, however, the highest densities of nesting shorebirds are found in wet sedge meadows (especially patterned meadows) and aquatic sedge and grass marshes. Raptors range over the majority of habitats while hunting, but a number of the species prefer the cliffs found along the Colville in the upper region of the delta.
The current major land uses in the Colville River Delta are oil extraction and subsistence harvesting by natives. Native people living in the town of Nuiqsut, as well as some small outlying camps, rely heavily on the river and lakes for fish and the rest of the area for hunting mammals, such as grizzly bear and caribou, and birds, mostly waterfowl. Currently, oil extraction is only taking place at one site, the Alpine Facility, which is located in the southwestern portion of the delta, between the Nigliq and Tamayayak channels, approximately 15 km north of the village of Nuiqsut. This facility also includes a pipeline that connects the Alpine Facility with the oil extraction infrastructure in the Prudhoe Bay area to the east of the delta. There are a number of small residentially developed areas in the delta - Nuiqust, which has approximately 500 inhabitants, and Colville 'Village' (a family homestead) on Anachilik Island. Ecotourism and ecological research also use a small portion of the area, mainly centered on the outer delta.