Deep Marsh Annuals

This tool lists various Habitat Fact Sheets developed by the Region 5 Regional Response Team. To suggest additions to this tool, please contact Barbi Lee. Click here for Inland Response Tactics Manual.

Rice Lake Deep Marsh
This example of the Deep Marsh Annual Habitat is dominated by wild rice Zizania aquatica but also includes incursions of other annual and perennial deep marsh plant species.

Image Credit: Steve Eggers, USACE
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Northern Wild Rice bed in Minnesota lake.
From a distance, wild rice beds appear similar to other common aquatic grasses and reeds.

Image Credit: Ducks Unlimited
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Wild Rice
Wild Rice Zizania aquatica and Northern Wild Rice Zizania palustris are large annual grasses native to lakes, marshes and rivers in the Great Lakes states.

Wild rice is considered an indicator species of deep and shallow annual marsh habitats. It can grow in dense stands or be intermixed with other aquatic plant species. The species requires specific growth conditions consisting of gently flowing waters, an organic or mud substrate and stable water levels during the growing season ranging from six inches to three feet.

Illustration credit: Patterson Clark
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Wild Rice stand in Pool 9 of the Upper Mississippi River.
Image Credit: USGS
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Floating leaf wild rice in Pool 8 of the Mississippi River.
Wild rice in floating leaf stage may be mistaken for algae or an aquatic plant species of lesser ecological and cultural value.

Image Credit: Matt Jacobson
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Wild Rice in floating leaf stage
Image Credit: 1854 Treaty Organization
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Wild Rice Harvest
Aerial shot depicting harvest paths through a wild rice bed in northern Wisconsin.

Image Credit: WI DNR
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Wild Rice Identification
Wild rice can reach heights of 10 feet. It's flat leaves can be two inches wide and three to four feet in length.

Image Credit: Merel R. Black
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Wild Rice Flowers
Wild rice are monoecious, meaning they have both male and female flowers. The female flowers develop before males flowers as small tufts of white near the top of the inflorescence. The drooping, showy pink and purple male flowers appear below on the same stem, and are much more conspicuous. Flowering typically occurs in mid-July through August.

Image Credit: UMN Extension
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I. Habitat Description

The deep marsh annuals habitat includes portions of lakes, ponds, marshes, or backwaters that are >10% vegetated with wild rice (Zizania). While this habitat is dominated by wild rice, it may have inclusions of submersed, non-rooted-floating aquatics, rooted-floating aquatics, or emergent vegetation. Deep marsh annuals are typically found in areas which are flooded semipermanently and have water depths between 0.25 and 2 meters with a silt or mucky bottom. During normal water conditions, there is little flow, though there can be wind-generated currents and stronger flows at inlets and outlets. During flood conditions, these habitats can be connected to rivers or streams, have strong currents, and the potential to carry large amounts of debris.

II. Sensitivity to Oil Spills

The deep marsh annuals habitat is highly sensitive to oil spills. This biologically diverse habitat provides a home to many plants and animal species, including amphibians, reptiles, fish, invertebrates as well as a wide variety of migratory waterfowl and plants. Many animal species use wetlands for reproductive and early life phases, during which they are most susceptible to the effects of oil. Significant loss of this habitat would greatly affect the populations of these animals and consequently, the local ecology. During normal water levels, oil would be less likely to penetrate water-saturated soils; during floods, oil could be deposited in areas that dry out after the flood, and penetrate the loose, organic-rich surface soils.

III. Sensitivity to Response Methods

Relevant response tactics are ordered below by least-to-most adverse habitat impact. Bullet points list quick-reference information regarding the tactic; any potential adverse impacts of its use; and suggestions for mitigation of these impacts if available. This is not intended to preclude the use of any particular tactic, but rather to aid responders in choosing the tactic(s) best suited to a specific habitat. For more information on a tactic, click on it or go to the corresponding section in the Inland Response Tactics Manual.

Additional Information

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Resources/Additional Information

General Classification Handbook for Floodplain Vegetation in Large River Systems

Inland Oil Spills: Options for Minimizing Environmental Impacts for Freshwater Spill Response

NatureServe

Natural Wetland Inventory

The U.S. National Vegetation Classification

Wild Rice Infographic

Least Adverse Habitat Impacts
Some Adverse Habitat Impact
Most Adverse Habitat Impact

Exclusion or Deflection Booming (see Inland Response Tactics Manual, pg. 3)

Boom can be used to exclude or deflect the spill away from sensitive resources.
Effectiveness is increased by positioning boom at appropriate angles for the current speed.

Sorbents/Sorbent Boom (see Inland Response Tactics Manual, pg. 22)

In areas with vegetation at or above water, sorbents are most effective in water surrounding vegetation (as opposed to within/on top of vegetated areas).
Care is necessary during placement and recovery to minimize disturbance of vegetation. Work in boats to avoid driving oil into the sediment.
Pom-pom type sorbents are best for heavy viscous oils that coat the strands; sorbent boom is best for light, low-viscosity oils that can penetrate into the sorbents.
Absorbent boom must be changed frequently to prevent it from becoming a source of sheen.

Flooding (see Inland Response Tactics Manual, pg. 15)

This tactic is only applicable in areas where the water level can be controlled, such as near locks and dams or in a small pond/marsh. Contact the U.S. Army Corps of Engineers water control regarding lock and dam operation.
Can be used selectively to remove localized heavy oiling This tactic is useful to remove oil trapped in vegetation, which can otherwise be difficult to herd toward recovery devices in open water. However, some oil may remain stranded in vegetation and will need to be removed through other means.

Low-Pressure, Ambient-Water Flushing (see Inland Response Tactics Manual, pg. 15)

Maintain low output pressures (less than 50 psi) to avoid disrupting the substrate and vegetation.
Effectiveness increases with lighter oils because less residual oil is left in the environment.
This tactic can be used with flooding to prevent re-deposition of oil.
Use for spot removal of oil because of the limited area of effectiveness.

In-Situ Burning (see Inland Response Tactics Manual, pg. 27)

Presence of a water layer on marsh surface can protect roots.
“Heavy ends” of petroleum product remain unburned and must be recovered. This residue will sink once it is cool.
The amount and placement of natural fuel in the surrounding area may present challenges to constraining the fire only to oiled areas. •
Authorization of in-situ burning is subject to RRT approval, consultation and concurrence from the state and the Department of the Interior.
May be one of the least physically damaging means of moderate and heavy oil removal as it leaves plant roots intact.
May be difficult to protect riparian vegetation.

Debris/Vegetation Removal (see Inland Response Tactics Manual, pg. 26)

Most appropriate for oils that form a persistent, thick, sticky coating on the vegetation, such as medium and heavy oils.
Removal will release trapped oil and speed natural flushing rates.
Debris may be associated with nests or living areas (e.g., beaver and muskrat lodges), therefore impacts on resident animal habitat need to be considered.
If oil is trapped in floating vegetation, removal may be the only way to recover the oil in the absence of water currents.
May be appropriate to prevent secondary oiling of wildlife.
Damage by cleanup crews may be reduced by avoiding excessive cutting/removal.
Response crews entering the marsh can inadvertently trample vegetation during cleanup/removal. To reduce this impact:

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