Avon River (Nova Scotia)
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__NOTOC__ The Avon River is a small
river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...
in central
Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native Eng ...
, Canada. A northerly flowing river, the Avon River's flow rises at an elevation of 145 metres (475 ft.) at Card and Bag Lakes on the South Mountain, a distance of approximately 29 kilometres (18 miles) southwest of the town of
Windsor Windsor may refer to: Places Australia * Windsor, New South Wales ** Municipality of Windsor, a former local government area * Windsor, Queensland, a suburb of Brisbane, Queensland **Shire of Windsor, a former local government authority around Wi ...
. Its meander length is . At Windsor Forks the main tributary, the West Branch Avon River, adds its flow, along with that of the Southwest Branch Avon, to the Avon. The West Branch Avon River rises at an elevation of 175 metres (574 ft.) at Black River Lake. Both the flows of the Avon and the West Branch have been impeded by hydropower developments in the early twentieth century. Near the rural community of
Martock Martock is a large village and civil parish in Somerset, England, situated on the edge of the Somerset Levels north west of Yeovil in the South Somerset district. The parish includes Hurst, approximately one mile south of the village, and Bow ...
, the river enters a broad glacial river valley forming a
ria A ria (; gl, ría) is a coastal inlet formed by the partial submergence of an unglaciated river valley. It is a drowned river valley that remains open to the sea. Definitions Typically rias have a Drainage system (geomorphology)#Dendritic dr ...
where it becomes
tidal Tidal is the adjectival form of tide. Tidal may also refer to: * ''Tidal'' (album), a 1996 album by Fiona Apple * Tidal (king), a king involved in the Battle of the Vale of Siddim * TidalCycles, a live coding environment for music * Tidal (servic ...
, creating an
estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...
for its remaining route to the
Minas Basin , image = Lookout On Way to Cape Split - 25006718579.jpg , alt = , caption = Looking east across the Southern Bight of Minas Basin from The Lookoff , image_bathymetry = , alt_bathymetry = , ca ...
at Kempt Shore, several kilometres downriver from the town of
Hantsport Hantsport is an unincorporated area in the West Hants Regional Municipality, Nova Scotia, Canada. It is at the western boundary between West Hants Regional Municipality and Kings County, along the west bank of the Avon River's tidal estuary. ...
. Another tributary, the St. Croix River joins just below Windsor creating a total watershed of 1,306 square kilometres. Rivers flowing into the Avon include the Halfway, Herbert, Cogmagun, Kennetcook and
St. Croix Saint Croix; nl, Sint-Kruis; french: link=no, Sainte-Croix; Danish and no, Sankt Croix, Taino: ''Ay Ay'' ( ) is an island in the Caribbean Sea, and a county and constituent district of the United States Virgin Islands (USVI), an unincor ...
. The Avon River is evident on many very early maps of the region and by 1686 is shown, along with its drainage basin, on
Jean-Baptiste-Louis Franquelin Jean-Baptiste-Louis Franquelin (1650-c.1712) was a French trader who was appointed in the early 1670s as the first cartographer in '' Nouvelle France'' (Canada) by the colony's governor. He was appointed in 1688 as royal hydrographer by Louis XIV. ...
's map in great detail.


Causeway and controversy

In 1970 the Avon River was completely obstructed by a rock and earth fill
causeway A causeway is a track, road or railway on the upper point of an embankment across "a low, or wet place, or piece of water". It can be constructed of earth, masonry, wood, or concrete. One of the earliest known wooden causeways is the Sweet Tra ...
immediately downstream from Windsor at its junction with the St. Croix River as part of the development of a controlled access expressway called
Highway 101 Highway 101 was an American country music band founded in 1986 in Los Angeles, California. The initial lineup consisted of Paulette Carlson (lead vocals), Jack Daniels (guitar), Curtis Stone (bass guitar, vocals), and Scott "Cactus" Moser (drums) ...
. The Avon River Causeway replaced an existing road bridge upriver from town and also resulted in the rerouting of the
Dominion Atlantic Railway The Dominion Atlantic Railway was a historic railway which operated in the western part of Nova Scotia in Canada, primarily through an agricultural district known as the Annapolis Valley. The Dominion Atlantic Railway was unusually diverse for a ...
's Halifax-
Yarmouth Yarmouth may refer to: Places Canada *Yarmouth County, Nova Scotia **Yarmouth, Nova Scotia **Municipality of the District of Yarmouth **Yarmouth (provincial electoral district) **Yarmouth (electoral district) * Yarmouth Township, Ontario *New ...
main line which used to run through Windsor's downtown, crossing the river on a bridge parallel to the road bridge immediately upriver from the town. The causeway controls the Avon River's discharge and the incoming tidal waters of the Minas Basin through a series of flood control gates which are intended to regulate the river's flowage to prevent flooding of agricultural lands upriver near Martock. The section of the Avon River upriver of the causeway along the Windsor waterfront is now a 'man-made' freshwater, Lake Pesaquid. The construction of the causeway has dramatically affected the Avon River downstream from Windsor, with large parts of the once-navigable river now being obstructed by large mud flats and vegetation, owing to the lack of tidal exchange and freshwater discharge. The nature writer Harry Thurston has noted, "Almost before the last stone was put in place, sediment began to accumulate to an alarming rate - 5 to 14 centimetres per month. Within seven years, a four metre high island of silt formed on the seaward side of the causeway; and the effects were felt 20 kilometres downstream, where two metres of mud impaired navigation at Hantsport."Harry Thurston, ''Tidal Life: A Natural History of the Bay of Fundy''. Camden House Publishing, 1990 Dr. Michael Risk of the University of Guelph, researching the build-up of a new mud flat on the seaward side of the causeway, "estimated that the bottom-dwelling creatures at Windsor were experiencing a two-thirds mortality rate", which led him to state the new formation was a "biological
desert A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About on ...
". The onset of the mud flat formation left the sediments in an initial state which were too soft to support organisms. The need to monitor and assess the impacts of such changes gave impetus to a greater interest in
Bay of Fundy The Bay of Fundy (french: Baie de Fundy) is a bay between the Canadian provinces of New Brunswick and Nova Scotia, with a small portion touching the U.S. state of Maine. It is an arm of the Gulf of Maine. Its extremely high tidal range is the hi ...
ecosystem and the ultimate establishment of the Acadia Centre for Estuarine Research (ACER) in Wolfville. Contrasting the initial decline of bottom-dwelling creatures, Dr. Graham Daborn of ACER found that zoo-plankton "are more abundant than previously thought. They appear to be able to thrive on non-living organic matter..." and that this "abundance of creatures at the lower end of the food chain suggests a considerable nursery role for the inner Bay." This notion is supported by research work completed by Dr. Sherman Bleakney of Acadia University. Recently announced plans for the expansion of Highway 101 between the
Halifax Regional Municipality Halifax is the capital and largest municipality of the Provinces and territories of Canada, Canadian province of Nova Scotia, and the largest municipality in Atlantic Canada. As of the 2021 Census, the municipal population was 439,819, with 348 ...
and the eastern end of the
Annapolis Valley The Annapolis Valley is a valley and region in the Canadian province of Nova Scotia. It is located in the western part of the Nova Scotia peninsula, formed by a trough between two parallel mountain ranges along the shore of the Bay of Fundy. St ...
have raised concerns about maintaining the Avon River causeway. An environmental lobby group, Friends of the Avon River (FAR), has called upon the Federal Fisheries Ministers to instigate a Comprehensive Environmental Impact Assessment Study (CEIA) of the complete Avon River Watershed in order to protect the Endangered Atlantic Salmon, the COSWIC listed American Eel and their 'critical habitats'. The Avon River Causeway has 'zero' fish passageway. Thus, impeding all fish species needing to migrate to their freshwater habitats, in order to complete their lifecycles. FAR reviewed and supported a report to have a more indepth study regarding the protection of fish species before the expansion of gypsum quarries within the river's watershed because of threats to river life, citing the use de-watering runoff from the quarries.FAR Press Release
/ref> A decision in August 2007 by the
New Brunswick New Brunswick (french: Nouveau-Brunswick, , locally ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. It is the only province with both English and ...
government to remove a similar causeway (constructed in 1968) blocking the
Petitcodiac River The Petitcodiac River is a river in south-eastern New Brunswick, Canada. Referred to as the "chocolate river" by local tourist businesses, it is characterized by its brown mud floor and brown waters. The river has a meander length of and is lo ...
, another tributary of the Bay of Fundy, to avoid facing charges under the federal ''Fisheries Act'', is expected to have ramifications for the Avon River causeway.


See also

*
List of rivers of Nova Scotia Nova Scotia's rivers all flow into the Atlantic Ocean through four unique watersheds: the Gulf of Maine, the Northumberland Strait, the Gulf of Saint Lawrence and into the Atlantic Ocean itself. Gulf of Maine The Gulf of Maine system includes ...


References


Further reading

* Danika van Proosdij and Sarah M. Townsend
"Sedimentation and Mechanisms of Salt Marsh Colonization on the Windsor Mudflats"
in ''The Changing Bay of Fundy—Beyond 400 Years'', 2004 * J.A. Percy
"The ‘Cause’ in Causeway: Crossing the Avon River at Windsor"
''Fundy Issues #28'' newsletter of the Bay of Fundy Ecosystem Partnership (BOFEP), Winter 2008.


External links


2004 study of environmental impacts of widening the causeway


{{authority control Landforms of Hants County, Nova Scotia Rivers of Nova Scotia