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Delta Marsh

Delta Marsh





Public Access: Yes

Current and Future Threats: There are many threats facing Delta Marsh. Due to the marsh’s proximity to the Portage Diversion outlet, the marsh periodically floods, impacting vegetation growth, and adding sediment and nutrient pollution. Due to Lake Manitoba’s water levels being stabilized for flood mitigation, much of the wetland has become a series of large shallow lakes. The beach ridge is also under pressure of further development of its land for cottages. Finally, invasive species have caused damage to the marsh’s biodiversity. Common carp have caused severe damage to the Delta Marsh ecosystem. Carp are bottom feeders which sift through sediment with their mouths in search of food. This suspends sediments, preventing the sun from penetrating the water. Low light prevents aquatic plants from growing, eventually decreasing biodiversity. Fortunately, Ducks Unlimited Canada, in partnership with Manitoba Agriculture and Resource Development and private stakeholders, has built exclusion screens and dikes to prevent carp from migrating into the marsh each spring. Delta Marsh has also been invaded by Typha x glauca, a hybrid of the narrow-leaved (Typha angustifolia) and broad-leaved cattail (Typha latifolia)This cattail is able to outcompete native marsh vegetation because it can thrive in both high and low water.

Conservation status: Ramsar Site

Adjacent Land Use: Surface Water. Delta Marsh is bordered on the south side by agricultural and pasture land and bordered by cottages on the beach ridge to the north.

Approximate natural buffer width: > 100 ft

Other information:



  • Currently a Ramsar Site
  • Supports significant numbers of wetland-dependent fauna, such as water birds or fish
  • Protects biological diverse wetland flora, fauna and/or their habitat

Delta Marsh is one of North America’s largest freshwater coastal wetlands. First Nations people utilized the marsh’s abundant flora and fauna for thousands of years, as evidenced by spear and arrow heads that wash up on the beach. In the early 20th century Delta Marsh became a world famous duck hunting location, a place where the rich and famous would come to hunt. Cottages were also built overlooking the lake as the beach ridge separating the marsh from Lake Manitoba became a popular recreation spot. By the 1960s, environmentalists and hunters noticed a severe drop in the duck populations as well as other negative changes to the environment. This, along with changing tastes in recreation, caused hunting to crash in popularity. Research by Ducks Unlimited Canada, in cooperation with the University of Manitoba Delta Marsh Field Station and other partners, discovered that invasive common carp (Cyprinus carpio) was one of the main contributors to the environmental decline, along with stabilized water levels, and nutrient loading. In 2006, much of the marsh was designated a Wildlife Management Area by the province of Manitoba.

The marsh was the home of two important field stations. The Delta Waterfowl Research Station was established in 1938, and the University of Manitoba Delta Marsh Field Station in 1966. Both stations hosted a variety of wetland and education activities, including university students and their research, conferences, seminars and school field trips. Unfortunately, both stations were damaged during a flood in 2011. The university field station closed, and while the waterfowl station also sustained damage, it still hosts some research activities.

Delta Marsh is one of the most distinct wetlands in Canada, boasting 307 species of birds, 360 plant species, as well as 31 species of fish. The marsh is an Important Bird Area according to IBA Canada, due to the thousands of waterfowl, shorebirds, songbirds, and gulls that use the marsh to breed or as a staging area during migration. The marsh was also part of the provincial Heritage Marsh Program before the program was discontinued. Delta Marsh being recognized as a Wetland of Distinction would draw attention to the many challenges facing this important habitat.

Exemplary Ecosystem Services:
  • Aesthetic/cultural heritage value/provisioning
  • Recreation (birdwatching, ecotourism)
  • Education/Research
  • Water quality improvement

Approximate size: 15,000 ha
General wetland characterization: 
  • Coastal Open Fresh Water
Adjacent Water Bod(ies): 
  • Lake
Name of body of water: Lake Manitoba

Surficial Geology: 10,000 years ago, Lake Agassiz covered much of Manitoba. When glacial Lake Agassiz drained around 9,500 years ago, the Manitoba Great Lakes were left behind as remnants. One of those lakes was Lake Manitoba. Around 4,500 years ago, the Assiniboine River flowed into Lake Manitoba. The sediment carried by the river created a delta. Wave action and water currents redistributed the sediments and formed a beach ridge, separating the marsh from the lake. Around 2,000 years ago the Assiniboine River changed course to the east, away from Lake Manitoba. This left behind the marsh as it is today, a series of bays, sloughs, flooded meadows, and former river channels.

If Adjacent to Stream, insert stream order: 

Soils: Delta Marsh contains two types of soil; gleysol, a wetland soil that is saturated with water unless drained, and regosol, soil that is weakly developed due to an unstable land surface. The soil is made up of thick deposits of muck and peat.


Dominant flora: Delta Marsh’s vegetation includes: Broadleaf cattail (Typha latifolia), Narrow-leaved cattail (Typha angustifolia), Hybrid cattail (Typha x glauca), Common Reed (Phragmites australis), Whitetop (Scolochloa festucacea), Sago Pondweed (Stuckenia pectinata), Northern Watermilfoil (Myriophyllum sibiricum), and Sheathed Pondweed (Stuckenia vaginata).

Unique flora: Common hackberry (Celtis occidentalis) – most northerly extent of this tree species is found on the beach ridge.

Dominant fauna: The most common waterfowl at Delta Marsh include: Mallards (Anas platyrhynchos), Northern Pintail (Anas acuta), Gadwall (Mareca strepera), Blue-Winged Teal (Spatula discors), American Widgeon (Mareca americana), Northern Shoveler (Spatula clypeata), Canvasback (Aythya valisineria), Redhead (Aythya americana), and Lesser Scaup (Aythya affinis). The most common songbirds at Delta Marsh include: Mourning Dove (Zenaida macroura), Eastern Kingbird (Tyrannus tyrannus), Western Kingbird (Tyrannus verticalis), Least Flycatcher (Empidonux minimus), Gray Catbird (Dumetella carolinensis), American Robin (Turdus migratorius), Warbling Vireo (Vireo gilvus), Yellow Warbler (Setophaga petechia), and Northern Oriole (Icterus galbula). The most common fish include: Fathead Minnow (Pimephales promelas), Common Carp (Cyprinus carpio), Common White Sucker (Catostomus commersonii), Northern Pike (Esox lucius), Black Bullhead (Ameiurus melas), and Yellow Perch (Perca flavescens). Amphibians: Western Tiger Salamander (Ambystoma mavortium diaboli) – SARA status lists the prairie populations as a species of Special Concern; Northern Leopard Frog (Lithobates pipiens) – SARA status lists it as a species of Special Concern; Canadian Toad (Anaxyrus hemiophrys); Wood Frog (Lithobates sylvaticus); and Boreal Chorus Frog (Pseudacris maculata).

Rare fauna: None.


Wooden sign welcoming visitors to the Delta Marsh Wildlife Management Area featuring an image of a duck in flight.
Aerial image of a mix of wetland vegetation and open water along the coastline
Image showing wetland vegetation growing in the water
A metal structure cutting across a rocky stream teaming with fish
Many gray fish gather along the edges of a metal barricade in the water
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