词条 | Fraser River |
释义 | Fraser River river, British Columbia, Canada major river of western North America, draining a huge, scenic region of some 92,000 square miles (238,000 square km) in central British Columbia. About 70 percent of the region drained is over 3,000 feet (900 m) high, and human exploitation of this rather isolated area has been relatively recent. The natural beauties of the river course (particularly its spectacular canyon section) and the surrounding countryside have nevertheless remained relatively unspoiled. The river was named for Simon Fraser (Fraser, Simon), who first descended it to the Pacific Ocean in 1808. The Cariboo gold rush, which began in 1858, took place in the Fraser River basin. From its source in Yellowhead Lake on the British Columbia–Alberta border, the Fraser flows 851 miles (1,370 km) to its mouth on the Strait of Georgia. From its mountain source, the river's course is initially northwestward, descending by gentle gradients along the Rocky Mountain trench. Near latitude 54° N the river makes a great bend southward to traverse the Interior Plateau and then the Coast Mountains. Entrenchment and gradients increase progressively downstream, and through the Coast Mountains the raging waters traverse a canyon about 5,000 feet (1,500 m) deep. Below this canyon the Fraser turns westward to flow placidly across an alluvial plain to its debouchment near Vancouver, B.C. The Thompson River, which enters the Fraser about 145 miles (235 km) from its mouth, is the most important of numerous tributaries, many of which rise in extensive mountain lakes. Navigation is important only in the tidal estuary where New Westminster serves deep-sea ships. The economy of the Fraser River basin is based mainly on forestry. Coniferous forests cover most of the Interior Plateau, except in the dry, southern valleys, which are covered with narrow strips of grassland on the lower slopes. Prior to 1940 small sawmills cut a little lumber along the three railway lines that crossed the basin. After 1950, however, the northward extension of the Pacific Great Eastern Railway (subsequently called the British Columbia Railway) and the improvement of highway facilities increased the accessibility of the forests and the merging of smaller companies, together with the introduction of pulp mills, consuming chips and small trees, heightened the utilization of forest resources. Forest products are either transported to Vancouver for overseas markets or are taken eastward by rail to central Canada and the midwestern United States. The turbulent Fraser River itself is not actually used in the forestry industry, even for the transport of logs to the sawmills. Agriculture has not developed greatly within the river basin, except for cattle ranching on the grasslands and upper level parklands in the Chilcotin Plateau, west of the Fraser River, and the Nicola Valley, south of the Thompson River. Ranching was established in the 1860s to supply the gold mining camps and then, after gold mining declined, to supply meat to the growing city of Vancouver. The Fraser River is the major producer of salmon in British Columbia, and its tributaries and headwater lakes are the spawning grounds of several species of salmon. These salmon ascend the river in late summer to spawn and then go downstream the following year to spend the next two or three years in the ocean. Because of these migratory habits, salmon fishing takes place mainly off the Fraser River mouth, and only Indians have fishing rights in the river basin itself. Hydroelectric exploitation of the river system may eventually threaten salmon migration. |
随便看 |
|
百科全书收录100133条中英文百科知识,基本涵盖了大多数领域的百科知识,是一部内容开放、自由的电子版百科全书。