Natural Resources
Conservation Service
Ecological site F090BY004WI
Loamy Floodplain
Last updated: 11/16/2023
Accessed: 12/22/2024
General information
Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
MLRA notes
Major Land Resource Area (MLRA): 090B–Central Wisconsin Thin Loess Dissected Till Plain
The Wisconsin and Minnesota Thin Loess MLRA, Northern and Southern Parts (90A and 90B) correspond closely to the North Central Forest and the Forest Transition Ecological Landscapes, respectively. Some of the following brief overview is borrowed from the Wisconsin Department of Natural Resources ecological landscape publications (2015).
The Wisconsin and Minnesota Thin Loess MLRA, Northern and Southern Parts (90A and 90B) is an extensive glacial landscape that comprised of over 11.1 million acres (17,370 sq mi) throughout central and northern Wisconsin – about 27% of the total land area in the state. This glacial landscape is comprised of a heterogenous mix of loess-capped ground moraines, end moraines with eskers and ice-walled lake plains, and pitted, unpitted, and collapsed outwash plains sometimes interspersed with drumlins from the Illinoian and Pre-Illinoian glaciations. The entire area has been glaciated and nearly all of it is underlain by dense glacial till that impedes drainage. An extensive morainal system – the Perkinstown end moraine – spans most of the width of northern Wisconsin and divides the Northern and Southern Parts of this large landscape. This moraine, which has been sliced by outwash in many places, marks the southernmost extent of the Wisconsin glaciation (Wisconsin’s most recent glacial advance).
North of the Perkinstown morainal system is a loess plain, with a loess mantle 15-60 cm thick. The northernmost edge of this landscape is an undulating till and outwash plain with materials deposited by the Chippewa Lobe. Drumlins are common in the northern and northeastern portions. The drumlins are oriented towards the southwest and formed during a glacial episode prior to the most recent glacial advance. Some are covered with glacial till. Pitted, unpitted, and collapsed outwash plains fill the spaces between drumlins. Detached from the major land mass to the northeast is the hummocky Hayward collapsed end moraines, where swamps, ice-walled lake plains, and eskers are common.
Most of the MLRA to the south of the Perkinstown morainal system is an extensive ground moraine with some proglacial stream features including pitted outwash plains, terraces, and fans. A layer of loess 6 to 47 inches (15-120 cm) thick covers much of the area. Like the Northern Part, all areas of the Southern Part of this MLRA were glaciated, although the southcentral portion is a relatively older till plain with materials from the Illinoian and pre-Illinoian glaciations, not the most recent Wisconsin glaciation. The landforms in the southcentral portion are highly variable. Much of the area topography is controlled by underlying bedrock. Sandstone outcrops and pediments can be found here. Some of the most southern portions of the MLRA are mixed glacial deposits and residuum.
The land surface of the southeastern portion was formed by many small glacial advances and retreats. Morainal ridges protrude through an erosional, pitted outwash-mantled surface. These parallel ridges run in a northeast to southwest orientation and are dissected by many steams.
The continental climate of this MLRA is typical of northcentral Wisconsin, with cold winters and warm summers. The southern boundary of this MLRA straddles Wisconsin’s Tension Zone, a zone of transition between Wisconsin’s northern and southern ecological landscapes. Historically, the mesic forests were dominated by eastern hemlock (Tsuga canadensis), sugar maple (Acer saccharum), and yellow birch (Betula alleghaniensis).
Classification relationships
Major Land Resource Area (MLRA): Wisconsin and Minnesota Thin Loess and Till (Northern and Southern Parts - 90A and 90B)
USFS Subregions: Central-Northwest Wisconsin Loess Plains (212Xd), Glidden Loamy Drift Plain (212Xa), Lincoln Formation Till Plain - Mixed Hardwoods (212Qb), Lincoln Formation Till Plain - Hemlock Hardwoods (212Qc), Brule and Paint Rivers Drumlinized Ground Moraine (212Xc), Perkinstown End Moraine (212Xe), Rib Mountain Rolling Ridges (212Qd), Rosemont Baldwin Plains and Moraines (222Md)
Small sections occur in Hayward Stagnation Moraines (212Xf), St. Croix Moraine (212Qa), Mille Lacs Uplands (212Kb), Green Bay Lobe Stagnation Moraine (212Ta)
Wisconsin DNR Ecological Landscapes: Western Prairie, Forest Transition, and North Central Forest
Ecological site concept
The Loamy Floodplain ecological site is found scattered throughout MLRA 90A and 90B in floodplains along streams and rivers that dissect expansive till plains and outwash plains. These sites are characterized by very deep, very poorly to moderately well drained soils that formed in loamy alluvium and lacustrine deposits. Sites are subject to frequent flooding in the spring and fall, and some sites are subject to frequent ponding. Some sites remain saturated for long durations and meet hydric soil requirements. Stream inflow, precipitation, runoff from adjacent uplands, and groundwater discharge are the primary sources of water. Soils range from very strongly acid to moderately alkaline.
The characteristic traits of Loamy Floodplain are their loamy textures and their location on a floodplain. The loamy textures, presence of carbonates, and higher pH and available water capacity differentiate these sites from their Sandy Floodplain counterparts.
Similar sites
F090BY003WI |
Sandy Floodplain Sandy Floodplain sites are found exclusively on floodplains in sandy and sometimes silty alluvium. These sites are somewhat poorly to poorly drained and are subject to flooding. Some sites may be saturated for long enough for hydric conditions to occur. They are found in similar landscape positions as Sandy Floodplain but have coarser textures. |
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F090BY006WI |
Wet Loamy Lowland Wet Loamy Lowland sites consist primarily of deep loamy deposits derived from a mixture of outwash, alluvium, loess, and lacustrine sources. Some sites may have bedrock contact within two meters of the surface. These sites are seasonally ponded depressions that remain saturated for sustained periods, allowing hydric conditions to occur. |
F090BY008WI |
Moist Sandy Bedrock Upland Moist Sandy Bedrock Upland sites consist of sandy to clayey alluvium, till, or eolian deposits over residuum weathered from bedrock. Bedrock contact occurs within two meters of the surface. Sites have seasonally high water table within a meter of the surface. Perching of the water table may occur as a result of bedrock contact. Vegetative communities supported by Loamy Floodplains are also supported by Moist Sandy Bedrock Upland sites. |
F090BY009WI |
Moist Sandy Upland Moist Sandy Lowland consist of deep sandy and loamy deposits derived from a mixture of alluvium, residuum, till, or lacustrine sources. The finer textures allow the soil to stay moist - but not saturated - for sustained periods during the growing season. Some vegetative communities supported by Loamy Floodplain are also supported by Moist Sandy Lowland. |
Table 1. Dominant plant species
Tree |
(1) Quercus alba |
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Shrub |
Not specified |
Herbaceous |
(1) Onoclea |
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Ecosystem states
State 1 submodel, plant communities
1.1B | - | Major flooding event depositing new sediment. |
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1.2B | - | Long period without major flooding. |