Natural Resources
Conservation Service
Ecological site F090BY003WI
Sandy Floodplain
Last updated: 11/16/2023
Accessed: 11/23/2024
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 6 to 24 inches (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 tp 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 This Loess and Till (Northern and Southern Parts - 90A and 90B)
USFS Subregions: Rib Mountain Rolling Ridges (212Qd), Lincoln Formation Till Plain - Hemlock Hardwoods (212Qc)
Wisconsin DNR Ecological Landscapes: Forest Transition
Ecological site concept
The Sandy Floodplain ecological site is an uncommon site in MLRA 90A and 90B, located on floodplains primarily along the Wisconsin and Big Rib, Big Eau Pleine rivers which occupy valleys filled with sandy outwash deposits. These sites are characterized by very deep, poorly to somewhat poorly drained soils that formed primarily in sandy alluvium. Sites are subject to frequent flooding in spring and fall, some sites are subject to ponding. Soils remain saturated for long duration during growing season and some sites meet hydric soil requirements. Stream inflow, precipitation, runoff from adjacent uplands, and groundwater discharge are the primary sources of water. Soils range from strongly acid to neutral.
The characteristic traits of Sandy Floodplain site are their sandy textures and their location on a floodplain. Vegetation must be tolerant of frequent floods. Sandy Floodplains lack carbonates and have a lower pH and available water capacity than their loamy counterparts.
Similar sites
F090BY004WI |
Loamy Floodplain Loamy Floodplain are found exclusively on floodplains in loamy alluvium, sometimes underlain by sandy alluvium. Soils are very poorly to moderately well 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 finer textures. |
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F090BY002WI |
Mucky Swamp Mucky swamp sites consist of deep, highly decomposed herbaceous organic materials. Some sites have mineral soil contact. They are very poorly drained and are neutral to slightly acid. These sites are permanently saturated wetlands. Some of the vegetative communities supported by Organic Nonacid sites may also be found on Sandy Floodplain. |
F090BY005WI |
Wet Sandy Lowland Wet Sandy Lowland sites consist of deep sandy deposits derived from a mixture of outwash, alluvium, and lacustrine sources. They form in seasonally ponded depressions and are saturated long enough for hydric conditions to occur. Some sites are wetlands. They support similar vegetative communities as Sandy Floodplain. |
Table 1. Dominant plant species
Tree |
(1) Acer rubrum |
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Shrub |
Not specified |
Herbaceous |
(1) Parthenocissus quinquefolia |
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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. |