Appalachia

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The Appalachian region is comprised of the island of Newfoundland, Nova Scotia, New Brunswick and Quebec south of the St Lawrence River (Fig. Map-1). The area has a low population density and forestry operations are widespread. Extensive surface water resources and high levels of precipitation ensure that surface water is the principal source of potable water.

The latitudinal range of the region and the continental and island components boarding the north Atlantic insure a diverse climatic regime from the east to west. Ocean water temperatures moderate the climate of the eastern maritime region. In winter the extensive ice cover of the St Lawrence can contribute to a more continental realm for bordering regions. Temperatures vary between the two distinct climatic regimes; the area of maritime climate has a temperature range from -2 to 17C, whereas the more continental climate has average winter lows of -7C and summer highs of 25C. The highest precipitation values are in excess of 1600 mm along the Newfoundland south coast and Cape Breton highlands. By contrast the continental area has a precipitation maximum of 1200 mm. Frequent thaws and rainstorms during mid winter in the maritime area can contribute to a complex hydraulic regime with large late winter run-off events triggered by moisture laden snow pack.

Forests of the continental part of the region are generally mixed conifers and deciduous stands of spruce, balsam fir, yellow birch, and sugar maple. In Newfoundland vegetation is diverse and ranges from the the moss-heath of the Avalon barren, which is unique in North America, to stands of balsam fir and black spruce on steep, moist, upland slopes. Much of the coastal region and raised domed bogs are dominated by dwarf, open patches of white spruce, black spruce and tamarack. Sphagnum peat bogs are a significant part of the landscape.

The Appalachian region can be divided into three broad physiographic regions, highlands, uplands and lowlands. The region is dominated by a well developed highland peneplain surface that is generally highest in the northwest and slopes southeastward to the ocean from 1500 m in Gaspe to less than half that in Cape Breton and Newfoundland. Upland areas are the most arealy extensive in the region and form a lower level of the regional peneplain surface. In New Brunswick large river valleys such as the Saint John River and Restigouche River valleys are entrenched in the peneplain. Lowland areas generally correspond with the Maritime basin.

The geology of the Appalachian represents an old, extensively eroded orogenic belt. Rock types of the area reflect the paleogeographic and tectonic evolution and include metamorphic, ophiolitic, mafic volcanic, carbonate, and clastic sediment. Granitic plutons occur across the region and make up one third of all exposed rocks. The surficial sediment cover of the area corresponds to the various physiographic regions. Highland areas are predominantly bedrock with thin discontinuous till cover, whereas upland areas have more extensive till cover (Grant, 1989). Eskers and other glacial landforms are common. Lowlands have thicker sediment cover and buried bedrock valleys.

Hydrogeology

Regionally bedrock aquifers are the most significant source of groundwater in the Appalachian region. In Newfoundland over 90 percent of water wells extract water from bedrock units. Similar trends are present across the rest of the region. Fracture permeability provides the primary groundwater storage with solution permeability being important locally. Ground water yield from fractured bedrock aquifers is generally low, having average yields of 5 - 45 l/m in Nova Scotia and Newfoundland. Monitoring and mapping of groundwater quality is being conducted from water sampling programs and proxy regional bedrock geochemistry. Natural geochemical elements of concern include arsenic, uranium, fluoride, barium, and lead. Newfoundland has mapped potential areas of arsenic concern using lake sediment geochemistry and bedrock lithology; demonstrating the close correlation that commonly occurs between geology and water quality.

In areas of thick surficial sediment well yields can be significantly higher. For example in Fredericton