Wetland Management

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History of Wetland Management 

  The history of wetland management on Bowdoin NWR starts with the authorization of the Milk River Project in 1903, one of the first irrigation projects initiated under the Reclamation Act of 1902. This act committed the Federal Government to fund the construction and management of irrigation projects for arid lands of 20 States in the American West. The U.S. Reclamation Service (now the Bureau of Reclamation) was established to oversee the development of all irrigation projects in the West. The Milk River Project is federally owned and supplies irrigation water to eight irrigation districts, eastward from Havre to Glasgow, MT. The purpose of this project is for irrigation and all other uses are secondary. 


 The Milk River Project starts near Glacier National Park where water from the St. Mary River is transferred overland via large pipes for 29 miles into the North Fork of the Milk River, and then into the Milk River. Eventually, this water flows into two reservoirs, Fresno and Nelson, for storage and later used by downstream irrigators in the Milk River watershed.


 Lake Bowdoin was owned and operated by the BOR and used primarily as a sump for irrigation return flows and excess runoff from the Milk River Project. Bowdoin was one of many national wildlife refuges established throughout the northern Great Plains to help restore declining waterfowl populations, which had been devastated by the loss of grassland and wetland habitats during the 1930’s Dust Bowl. In 1936, Bowdoin NWR was established as an overlay on lands owned and operated by BOR, with both agencies having jurisdiction. Even before Bowdoin became a refuge, infrastructure was being constructed to hold and move water on said land. 


 The Dodson South Canal is part of the Milk River Project, and runs along the entire north boundary of the Refuge. This canal was created to deliver water stored in Fresno Reservoir to downstream irrigators and for water storage in Nelson Reservoir, not for wildlife purposes. It was not until 1937 the Service acquired a water use for the refuge through the terms of an agreement between the Service and the BOR. Water is diverted from the Dodson South Canal onto the Refuge to Lake Bowdoin and other refuge wetlands via smaller delivery canals and water control structures. The refuge went from managing one large wetland, Lake Bowdoin, to managing twenty.


Wetland Management 


  The motto for wildlife managers during the Dust Bowl era was to hold water for waterfowl use, as high as possible, for as long as possible, which in turn lead to developing wetland basins from depressions in the landscape to wetlands that were deeper. This motto for holding water high and long resulted in an immediate response by waterfowl. Birds took to the new habitat, only emphasizing the idea of more water. 


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Holding water wasn't the only thing early managers did for waterfowl. Aquatic vegetation such as cattail and bulrush was encouraged to provide cover for duck nests and broods. Overwater nesters, such as, black-crowned night herons, Franklin's gulls, eared grebes, and white-faced ibis', have also taken advantage of the increasing vegetation growing in wetlands, making refuge management not only for the ducks! Below the surface of the water, sago pond weed provides excellent food for water birds. Back in the early stages of the refuge, managers would transplant this species to entice it to grow in other wetlands.   


 This old management philosophy of holding as much water as possible throughout the year was not always beneficial to wetlands and birds. Over the decades, managers have learned wetlands are dynamic, ever changing, and need periods of everything from dry years to flooded years. Wetland vegetation also changes based on water levels. For example, constant, high water levels lead to choked wetlands of both below water (submergent) and above water (emergent) vegetation.


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Today, managers also look at water quality, vegetation composition, weather, and bird use to determine management techniques needed to keep these wetlands productive. Some of the tools of the trade include drawing wetlands down completely or holding wetlands at different water levels each year. Vegetation control also includes draw-downs, because exposing sediments encourages new growth of plants, that provide food for various birds. We have learned floods can be a good thing. Natural flooding allows water to move into basins and back out as water recedes, thus freshening or “flushing” wetlands. Flooding can also help control unwanted vegetation by having water levels too high for certain plants to establish. Cattails in particular are a plant that needs monitoring and management, for they can take over and choke out a wetland. When a wetland is choked out by cattail, the ability for ducks to land, take off, or even swim is gone. Vegetation diversity, that supplies food for birds, is decreased, and the overall wetland productivity is diminished. 
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Cattails can be controlled using draw-downs in conjunction with mowing, grazing, and/or discing, and herbicide treatments. Cattails can also be controlled by flooding if the water is higher than the young shoots. 

Carp too can degrade a wetland's productivity and use by waterfowl. Carp are a non-native fish from Asia. When they feed, they stir up sediment, causing the water to become turbid. The turbidity decreases the ability for aquatic vegetation to grow due to lack of sunlight. The most effective way to control carp are to draw down a wetland completely, or allow for a winter kill.

During the field season, wetland managers on Bowdoin look at past, present, and future wetland management to determine what techniques are working and which are not. This helps managers develop an annual management plan so that quality habitat can be provided to a whole host of bird species year after year.