The melting of snow along with spring rain can create serious flooding and devastating effects caused by flood waters. Forecasting possible flooding, and warning residents along the Mississippi and Carp Rivers and their tributaries of the danger, are key responsibilities of Mississippi Valley Conservation Authority (MVCA). Here are some areas which are particularly prone to flooding:
Lanark Highlands (formerly Village of Lanark)
Situated on the Clyde River approximately 20 kilometres north of Perth on Highway 511, the potential for flooding in the village is due to three major reasons:
- several buildings are located within the natural floodplain of the Clyde River
- the main street bridge does not have the capacity to pass spring flow discharge therefore causing a backwater effect
- there is minimal storage available on the Clyde River to reduce spring flow magnitudes
Clyde River from Cedardale to Lanark
A small cottage community located on the Clyde River approximately 15 kilometres north of the former Village of Lanark, Cedardale is becoming a year round residential area. Most of the residences within the floodplain have been removed by MVCA, however, it still has the potential for flooding problems from a Class 3 or greater flood.
Crotch Lake to Dalhousie Lake
Flooding on Crotch Lake normally occurs when heavy rains are received at the same time the lakes are at or near their maximum level. When this happens, the structure is overtopped and flooding occurs. This flooding is normally associated with the Mississippi River through the Village of Snow Road and around the shoreline of Dalhousie Lake. Flooding will likely extend down through to Sheridan’s Rapids on the Mississippi River.
Innisville and Mississppi Lake
Innisville is located on the Mississippi River approximately 15 kilometres east of Perth on Highway 7. The river flows into Mississippi Lake at this point and due to the set of rapids and the bridge abutments across the river, this area is subject to ice jams and minor flooding from backwater. Mississippi Lake is well developed with both seasonal and year round residences. Many of these residences are either partially or totally within the floodplain of the lake and are therefore subject to potential flooding during the spring freshet.
Town of Carleton Place, Glen Isle and Appleton
Carleton Place is located at the outlet of Mississippi Lake on the Mississippi River. Some portions of the town along the river are subject to potential flooding since they are located within the natural floodplain of the river. Possible ice jams at the main street bridge (Bridge Street) could aggravate potential flood conditions.
Glen Isle is immediately downstream of Carleton Place and is a year round residential area. Most of the houses and property in this area are partially within the floodplain of the river and therefore subjected to potential annual flooding.
Appleton is immediately down river of Glen Isle. Potential flooding in this village results mainly from ice jamming at the street bridge and backwater effects from the former dam.
Mississippi Mills (formerly Town of Almonte & Village of Pakenham)
Almonte is located on the Mississippi River approximately 15 kilometres downstream of Carleton Place. Flooding occurs annually at the fairgrounds which is located within the floodplain and there is also potential┬áfor ice jams building at the upstream bridge in the downtown core.
Flooding caused by ice jams has also occurred on the Indian River, located approximately 8 kilometres downstream of Almonte, especially at the Mill of Kintail museum.
Riverbend Trailer Park, located on the outskirts of Pakenham has been built in the floodplain of the Mississippi River and is also subjected to potential annual flooding.
The Carp River is approximately 50 kilometres long and extends from Nepean to its outlet into the Ottawa River in Fitzroy. Flooding occurs in this river annually due to its limited channel capacity and no storage area. Most of the area flooded is farmland, however, the river flows through the centre of two villages, Carp and Kinburn, making them potential damage centres. Township roads are also inundated by flood waters during the spring runoff.
The portion of the Ottawa River shoreline which lies within MVCA jurisdiction extends from Marshall Bay to Shirley’s Bay. The main problem area associated with flooding along this stretch of the river is Constance Bay. The flooding along the Ottawa River usually occurs when heavy rainfall and moderate to high winds coincide with the spring freshet and the river is at or near flood stage levels, resulting in overtopping of the banks.
Areas which have experienced this phenomenon in the past include, but are not limited to, Clyde River, Fall River, Indian River, Mississippi River at Snow Road, Sheridan Rapids, Playfairville, Ferguson Falls, Innisville, Appleton, Almonte, Blakeney and Pakenham. For more information on frazil ice click here.