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A. ENVIRONMENTAL
CONDITIONS
- A.7 MAJOR WATERSHEDS AREA
- 7.1 Cape George
A.7 WATERSHEDS
The geological features of the study area define the landform, and therefore the patterns of surface run-off. The watersheds of the area thus can be discussed as groups with similar characteristics, but with distinctions based on local conditions and land use.
Figure A.7-1 presents the regions within the study area which will be discussed.
A.7.1 Cape George
The prominent geographical feature is the Antigonish-Pictou Highlands, which produces a series of small streams flowing northward into the Northumberland Strait and eastward into St. Georges Bay. The vegetation and wildlife of this area is representative of the Avalon Uplands. Much of the land is steeply sloped, so this area has historically remained forested rather than being cleared for human settlement.
The individual drainage basins within the region comprise small areas, beginning at high elevations but rapidly coming to sea level because of the topography. The drainage areas of these watersheds range from 2,400 to 4,200 hectares (Maritime Resource Management Services, 1982). Information on the discharge volumes of these streams was not found.
Stream water quality studies have not been found, but would be expected to be similar to other waters originating in the hard rocks of the Avalon Uplands; that is to be somewhat low in dissolved minerals. The eastward flowing streams travel over Carboniferous bedrock and richer soils surrounding the bay, so the water quality would be expected to differ, having higher concentrations of dissolved minerals.
A portion of the coastal land to the west is underlain by sedimentary rock, thus the landscape is more typical of Carboniferous lowlands; Merigomish, Woodburne and Barney soils are deposited on gently rolling topography, providing more fertile, well drained shaly loams used for agriculture.
The extent of forestry activity in this region is unknown, but based on inspection of digital images, and known age classes of forests of Antigonish county, this large resource area has been well utilized. A great deal of the clearing of trees during initial settlement has grown back as forest. Agriculture persists at a limited level, confined to the eastern and western coastal areas.
Human residence is concentrated in coastal fishing communities. Fisheries are significant to the economy. There are active commercial ports at Bailey's Brook, Arisaig, Malignant Cove, Livingstones Cove , Ballantyne's Cove and Cribben's Point. There is also a lobster pound in Arisaig. Tourism is a feature of the local area insomuch as the scenic value is considerable and there are notable features along the coast which include exposed fossiliferous rocks, cultural and community attractions.
A.7.2 St. Georges Bay South
The mainland watersheds of the study area emptying into St. Georges Bay drain a large basin within the Carboniferous Lowlands. Queens and Woodburne soils support a great deal of settlement and agriculture. Much of the length of the rivers in the basin have depositions of gravel and silt on the river flood plain, providing the base for a very good agricultural soil.
Antigonish Harbour receives water from the relatively large combined watersheds of the Right's, West, and South Rivers, covering 685 km2. The patterns of watershed usage are similar along each of these rivers. They all originate in forested areas, and are therefore affected by a certain amount of forestry activity. The rivers then pass through agricultural land receiving some runoff and disturbance associated with these activities, converging at the Harbour. There are deposits of conglomerate and salt in the upper reaches of the Rights and West River. The combined watersheds of the basin contain 14 small lakes.
The Rights River originates along the south-eastern face of the Antigonish-Pictou Highlands and travels south and eastwards through farmland, emptying into Antigonish Harbour. The drainage area of the watershed is 12,960 hectares including the North and South branches (Maritime Resource Management Services, 1982). The watershed area was actually increased by 100 hectares in 1973 by diverting Vincent Lake drainage into the South Rights River (MacLellan and Associates Inc., 1995).
The Rights River enters the harbour at the east end of the community of Antigonish and has caused serious property damage for residents in that area due to flooding during spring ice break-up. A hydrotechnical study was carried out in 1983 by MacLaren Plansearch to identify flood hazard zones. MacLellan and Associates (1995) prepared a report for development of plans to control ice jams. This document states that the flood problems occur in areas where the river historically flowed, and that the stream path has been modified in the past. Some jam control measures have included further modification of the river path.
The West River watershed covers an area of 35,560 ha. This watershed provides the water source for the town, and also includes the former Antigonish County landfill site. The headwaters of the various tributaries originate on Carboniferous rocks, extending into Pictou and Guysborough Counties. The Brierly Brook tributary of the river runs directly through Antigonish town, and therefore receives a considerable amount of street and wastewater run off. A considerable amount of habitat restoration work has been carried out on this stream. No background surface water studies have been found for this area, but a Nova Scotia Ground Water survey in 1972 &endash;1973 included a site near the mouth of the West River.
The South River watershed covers an area of 19,940 hectares to the south of Antigonish town. The area has extensive agricultural activity and a sewage treatment plant is located at Lower South River. The province operates a fish hatchery at Fraser's Mills, utilizing the river water, and collecting water quality data. Young (1971) published water quality data for three sites along the South River. Lakes within the watershed include Cameron's, Gillis, Kimballs and Copper Lake.
Stream discharge rates at St. Andrews are available from 1969 to 1974 and the National Water Quality Monitoring Program covered the same site (see Section A.8.2).
A.7.2.1 Antigonish Harbour
The harbour is a brackish tidal area, separated from the ocean by barrier beaches (Seymour, 1997). It is used extensively for recreational activities, including recreational fishing, ice fishing, boating, and hunting.
The harbour is not active in the commercial fishery, but the town , the largest urban centre in the study area, has various businesses. A regional hospital and university are major employers.
The waters are a rich, relatively undisturbed feeding ground for resident and migrating waterfowl, and support a diversity of marine and estuarine fauna. Extensive areas of cordgrass (Spartina ), grow in the salt marshes of the harbour, and on the shallow flats, eelgrass (Zostera ) is abundant (Erskine, 1992). Water quality data for the harbour has not been identified.
A.7.2.2 Pomquet River
The Pomquet River has two major tributaries, the West Pomquet River and the Black Avon River. The drainage area of these total 16,995 ha. Studies of water quality have not been found. River surveys of Pomquet and West Pomquet as trout habitat have been published by Miles (1983).
The community of Heatherton lies within the watershed on the Black Avon River. Pomquet Beach has a well developed sandy beach and extensive harbour. There has been a great deal of study of the resident algae in this harbour. The distribution of ecosystem types in the Pomquet watershed system are presented in Figure A.7-2.
Afton, Monastery, Tracadie, Little Tracadie and Wrights Rivers are a series of small rivers whose watersheds range from 1,820 to 11,030 ha in area (Maritime Resource Management Services, 1982). They are located to the east of Pomquet, draining the Mulgrave Plateau. There seems to be a general lack of information about this region. The bedrock geology of most of the watersheds is metamorphic bedrock of the Canso Group. The Halifax soils which predominant here are gritty sandy loam, which are very stony, often with a thick surface peat layer. The soils alternate from well to poorly drained resulting from an undulating topography. The resulting vegetation patterns are characterized by bands of bog in the lowland areas, and stands of hardwood along the ridges (Davis and Browne, 1996).
The coastal area is underlain by Carboniferous rock; the elevation is lower, and the land more fertile approaching the coast. Agriculture is restricted to this small area. The communities here have active fishing ports, Bayfied, Havre Boucher, Tracadie, Bayfield and Auld's Cove. Human settlement is primarily along the coast. This region of watersheds extends to the Canso Causeway.
Figure A.7-2. The Landforms and Ecosystems of the Northumberland Coast Natural History of Nova Scotia.
A.7.3 Southwest Cape Breton Watersheds
The land flanking the eastern side of St. George's Bay is underlain by a continuation of the body of sedimentary rocks that form the Antigonish basin. The Creignish Hills lie just inland of this, thus restricting the coastal lowlands to a narrow strip.
This coastal formation is known as the Judique Coastal Plain. As in the Antigonish area, the soils are moderately to poorly drained, moderately fine-grained red brown Carboniferous and have a clay loam texture. The surface drainage patterns reflect those of the Pictou Antigonish Highlands, producing small watersheds draining into the St. Georges Bay from Port Hastings to Judique.
To the north, adjacent highlands begin to recede inland, forming progressively larger drainage basins. The Graham River originates deeper inland in the Creignish Hills and travels through foothills before entering the ocean in Judique.
The total coastal drainage area is approximately 16,000 hectares (Maritime Resource Management Services, 1982). No surface water quality has been found for the area. Settlement is greatest along the coast. There are three active fishing harbours in the Judique area and one each at Port Hood and Port Hood Island. Port Hood is the site of surfacing for the Carboniferous Riversdale group, which is a coal producing body. A coalmine was active there until the 1960's.
Mabou Harbour is the collection point of larger watersheds that extend inland into the Ainslie Uplands to the north of the Creignish Hills. The underlying rocks are chiefly of the Horton group. The soils of the higher grounds, chiefly Diligence and Woodburne are well drained, but stony. Falmouth and Queens soils are found on lower lands, associated with gypsum deposits.
To the north, St. Georges Bay opens up to the Northumberland Strait. Here, the Mabou Highlands rise directly out of the sea. Stream drainage from these highlands are radial flowing both to the ocean and to inland watersheds. The Highlands are a portion of the Avalon Uplands, of metamorphic and igneous bedrock. It is similar in most respects to the Pictou-Antigonish Highlands, except that the surrounding Horton rocks are eroded away. Thom soils, characterized by stony, sandy loam yielding good drainage, with pockets of peat predominate. The slopes and a portion of the highlands have not been settled, therefore providing good wilderness habitat.
Streams running inland from the Mabou highlands collect in the Broad Cove River. This river drains a watershed of 5,720 ha, northward emptying into the Northumberland Strait north of Inverness. An active fishing harbour and wharf are located in a relatively small inlet to the south of Inverness, and another wharf is located at Broad Cove Marsh.
A municipal sewage treatment plant and a water treatment plant operate here, and a fish processing plant is located near the harbour.
A.7.4 The Margaree River
The Margaree River drains an extensive and diverse watershed totaling 122,255 ha. There are two main branches; the Southwest Margaree which runs northward from Lake Ainslie, a 56 km2 lake, and the Northeast Margaree River which runs south, originating in the Cape Breton Highlands. The river has been well studied over the last century. The scenery and recreational salmon fishery of the river system distinguish the area. A fish hatchery has been operational there since 1902. Discharge has been monitored on both branches of the watershed, one since 1918. Water quality has also been monitored on both branches. The landforms and associated ecosystems of the northern portion of the Margaree watershed are presented in Figure A.7-3.
Figure A.7-3. Landforms and Ecosystems of the Margaree Area, Natural History of Nova Scotia.
The River has recently been declared a Heritage River. The process leading up to this produced an extensive inventory of the valued features of the area (Rutherford and Assoc., 1988). The watershed includes four designated 'Protected Areas'; a portion of Jim Campbells Barren, the Margaree River, Sugarloaf Mountain and Trout Brook Wilderness Areas. The river has associated with it a large floodplain. The physical oceanography of the Margaree estuary is described by Kraul (1969).
There are no large population centers in this region. Some agriculture is carried out in proximity to the river. The main river and the Southwest branch are the site of the largest commercial gaspereau fishery in the study area. Lake Ainslie is the spawning grounds for the gaspereau, and is used extensively for recreational fishing and boating. The western tip is flanked by a unique alkaline bog which contains a number of uncommon plant species. The Inverness County Landfill site and a currently inactive barite mine, are both located immediately adjacent to Lake Ainslie.
A.7.5 Cape Breton Highlands Watersheds
Watersheds of northern Inverness County, the Cheticamp, MacKenzie and Grand Anse Rivers all originate on the plateaus of the Cape Breton Highlands, draining the Taiga and Highlands habitats. There is little exposure to human activity in this region. The slopes of the river valleys are steep. There are narrow zones of Carboniferous rock along the coast where each of these rivers enter the ocean, upon which the settlements of Cheticamp and Pleasant Bay are located. The settlements here have relied chiefly on fishing; agricultural land is limited to the small Carboniferous bodies along the coast.
The majority of the watershed areas of these rivers are within the boundaries of the Cape Breton Highlands National Park. Because of this, monitoring and management of the rivers and their resources are under park jurisdiction. This includes managing the salmon population in conjunction with the Department of Fisheries and Oceans
Cheticamp is one of the points of entry to the Cape Breton Highlands National Park. The watershed of the Cheticamp River extends into the Cape Breton Highlands, covering 2,705 ha. Approximately 10 % of the outflow of the Cheticamp Lake, has been diverted from the Cheticamp River system to the east, for use in the Wreck Cove hydroelectric project. Water quality and discharge data have been collected for this river. A very active fishing harbour is located at the village located to the south of the mouth of the river. The fishery and fish processing are very important to the local economy.
MacKenzie and Grand Anse Rivers both meet the sea at a small coastal plain upon which the Pleasant Bay community is located. Discharge and water quality data has been collected for the MacKenzie River.
A portion of the Cape Breton Highlands have been maintained as a national park since 1936. The National Park is an uninhabited area of unique physiography and habitat that covers 950 km2. The unique habitat, as well as its remoteness have prompted interest from the academic community.
A.7.6. Summary
The distribution of conditions that support the terrestrial biological system is primarily influenced by the geological composition of the study area. Metamorphic and igneous rock form the highland area. The conditions predominating at these high altitudes are lower temperatures, rough terrain, and because of the nature the bedrock, soil has formed which is, coarse with low fertility and low capacity to hold water. The biological system existing there is less productive and more specialized for these conditions, and is therefore less capable of adapting to changing conditions. Much of this land has been left unsettled, and is utilized as forestry land and wildlife habitat.
The varying degrees of erodibilty in the soft Carboniferous rock produce a continuum of elevation from the highlands to the lowlands. The resulting soils also occur on a continuum from insufficiently eroded for fertile conditions, to so finely textured that drainage of water is obstructed. The chemical composition of late carboniferous depositions (salts and carbonates), are released into the environment more readily and therefore confers a higher level of productivity upon the biological system living upon it. This land has been utilized for settlement and agriculture.
Watersheds within the study area reflect regional geography and geology. Size, productivity and human utilization of the watersheds vary between regions. Watersheds draining highlands are generally small, with a greater concentration of settlement and human activity along the coast. The inland forests are utilized and fisheries are important to coastal communities.
Larger watersheds have formed in the lowlands which empty into productive estuaries and in some cases, active harbours. Agriculture is important in these watersheds, and the distribution of settlement is more uniform.