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Wetlands

, Volume 39, Issue 4, pp 685–703 | Cite as

Improving Hydric Soil Identification in Areas Containing Problematic Red Parent Materials: a Nationwide Collaborative Mapping Approach

  • Sara C. Mack
  • Jacob F. BerkowitzEmail author
  • Martin C. Rabenhorst
Open Access
Applied Wetland Science

Abstract

Hydric soil identification utilizes diagnostic morphologic features, including iron transformations, resulting from anaerobic conditions. However, soils derived from some red parent materials (RPM) fail to develop characteristic hydric soils morphologies, confounding hydric soil and wetland delineation. Laboratory and field methods addressing resistant RPM soils exist, but application remains limited by uncertainty regarding problematic RPM distribution. In response, a collaborative effort (>50 participants) documented problematic RPM distribution across the contiguous United States. Specifically, >1100 samples from >450 locations underwent laboratory analysis using the Color Change Propensity Index to identify problematic RPM soils. Geospatial analysis linked verified problematic soils with associated geologic units and soil series, generating maps of RPM distribution. Potential problematic RPM was identified in the Northeast and Mid-Atlantic, Great Lakes, South-central, and Desert Southwest-Western Mountains (problematic RPM regions herein), encompassing diverse groups of soils and parent materials. Despite the observed variability in soil characteristics, results suggest that problematic RPM was consistently derived from sedimentary, hematite-rich red bed formations developed where deposition of terrestrial sediments occurred in near-shore, marginal-marine environments. Understanding problematic RPM soils distribution promotes the appropriate application of existing hydric soil field indicators, including F21 – Red Parent Material, thus improving approaches to hydric soil identification and wetland management.

Keywords

Hydric soil Red parent material Wetland delineation Sedimentary red beds 

Introduction

Hydric Soil Morphology and Problematic Hydric Soils

The United States Army Corps of Engineers (USACE) wetland delineation manual and associated regional supplements provide technical guidance and procedures for identifying and delineating wetlands (Environmental Laboratory 1987; Wakeley 2002). Accordingly, identification and delineation of wetlands utilizes a three-factor approach encompassing indicators of wetland hydrology (e.g., near surface, seasonally high water tables), hydrophytic vegetation (water-loving plants), and hydric soils. In general, each of these factors are identified using readily applicable field indicators (Environmnetal Laboratory 1987; Berkowitz 2011a; USACE 2012; Tiner 2016).

Hydric soils are defined as “soils that have formed under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper part” (Federal Register 1994). These periods of saturation, when combined with soil-microbial activity and the depletion of oxygen, promote biogeochemical processes that result in morphological features particularly useful for wetland identification during both wet and dry periods (Craft 2000; USDA-NRCS 2017). Common hydric soil morphologic features include: 1) the accumulation of organic matter from reduced rates of microbial decomposition under anaerobic conditions; and 2) the reduction and dissolution of ferric iron followed by subsequent translocation and depletion of ferrous iron phases (Reddy and DeLaune 2008). In particular, these iron reaction processes result in the formation of redoximorphic features that account for the prevalence of low chroma, Fe-depleted matrix colors associated with many mineral wetland soils (Vasilas and Berkowitz 2016; Rabenhorst 2011). The characteristic morphologies associated with prolonged saturation and aerobic conditions form the basis of field indicators of hydric soils, providing rapid and reliable approaches to identifying hydric soils utilized as part of wetland delineation procedures (USDA-NRCS 2017; Berkowitz 2011b).

In some cases, however, wetland areas exhibit the presence of hydrophytic vegetation and wetland hydrology, yet lack typical hydric soil morphological features due to natural conditions (Environmental Laboratory 1987). These soils are called “problematic hydric soils” (Vepraskas and Sprecher 1997; Robinette et al. 2011). Common examples of problematic hydric soils include: soils with low iron and/or organic matter contents that preclude the formation of redoximorphic features, high alkalinity soils that inhibit iron transformations, and recently deposited soil materials that simply have not been in place long enough to develop characteristic hydromorphic properties (USACE 2012; Tiner 2016). Additionally, some problematic soils result from factors related to parent material characteristics. For example, soils derived from dark parent materials (e.g. black coal deposits) mask morphological patterns associated with soil wetness (Stolt et al. 2001; U.S. Army Corps of Engineers 2012). These problematic soils led to the development and use of several field indicators of hydric soils specifically addressing a particular phenomenon or landscape position (e.g., F19 - Piedmont Flood Plain Soils; S11 – High Chroma Sands; Berkowitz and Sallee 2011; USDA-NRCS 2017).

Problematic Red Parent Material Soils

It has long been recognized that soils derived from certain red-colored parent materials (RPM) fail to develop soil morphologies (i.e., Fe-depleted matrix colors) characteristic of most wetlands, even where prolonged soil saturation and anaerobic conditions occur (Mokma and Sprecher 1994). Wetland delineation practitioners identified RPM as one of the most common problematic soil situations, accounting for up to 20% of the difficult soil scenarios reported in a national dataset examining wetland evaluation procedures across the United States (Berkowitz 2011b). Guidance was developed as early as 1996 to aid in the identification of wetlands in soils derived from RPM, with additional strategies described in recently published regional supplements to the USACE wetland delineation manual (USACE 2012).

Previous and on-going research suggests that these problematic RPM soils exhibit resistance to color change due to mineralogical characteristics inherited from their parent materials (USDA-NRCS 2017), and therefore occur in association with particular geological formations. For example, Niroomand and Tedrow (1990) demonstrated that soils derived from red shales resisted color changes under both field and laboratory conditions compared with soils derived from the other formations within the same area of New Jersey. Red soils from stratigraphically-related formations in Maryland and Connecticut also lacked prominent redoximorphic features despite highly-reducing conditions observed during field studies (Elless et al. 1996; Rabenhorst 2011; Ford 2014). Similar findings were reported across a range of formation types and geographic locations including soil hydrosequences derived from red-colored lacustrine deposits in Michigan (Mokma and Sprecher 1994), clayey alluvial deposits derived from red beds in Louisiana (Rabenhorst and Parikh 2000), and glacio-lacustrine sediments in Minnesota and Wisconsin (Petersen et al. 1967; Wheeler et al. 1999).

While these case studies demonstrate that some red soils are problematic, the majority of red soils or soils derived from red-colored parent material readily form hydromorphic features under anaerobic conditions (Rabenhorst and Parikh 2000). For example, red soils derived from metabasaltic rocks high in ferromagnetic elements and soils derived from red-colored fluviodeltaic sands displayed no resistance to color change despite the presence of red colors indicative of parent materials with high iron content (Sirkin 1986; Schwertmann 1993). Further, red soils derived from metamorphic and paracrystalline rocks associated with the Congaree River floodplains in North and South Carolina also do not exhibit a resistance to color change, despite the predominance of colors often 5YR or redder (USDA-NRCS 2017).

To explore the issue of color change resistance in red soils, Rabenhorst and Parikh (2000) developed a laboratory approach that distinguishes between red soils that were problematic (i.e. resistant to color change) and those that displayed color change propensity. In their study, red soils (both suspected problematic RPM and non-problematic RPM) were collected and treated with a sodium dithionite reducing agent in various treatments of differing periods of time and temperatures. Following treatments, digital colorimeter measurements documented shifts in Munsell color components (hue, value, chroma). Based on observed color changes, an equation quantifying the inherent capacity of the soils to form redoximorphic features (i.e. change color) under reducing conditions was developed; entitled the Color Change Propensity Index (CCPI). The CCPI groups soils into three categories: 1) non-problematic RPM soils displaying no color change resistance (CCPI values >40); 2) problematic RPM soils that resisted color change under reducing conditions (CCPI <30); and 3) an intermediate range with CCPI values in which soils displayed limited color change resistance representing a group of potentially problematic RPM (CCPI = 30–40). The CCPI provided a procedure for quantitatively identifying problematic RPM, contributing to the development of a field indicator of hydric soils to help improve wetland delineation approaches in areas containing RPM.

Development of F21 Red Parent Material

In order to address hydric soil delineation challenges associated with problematic RPM soils, a field indicator of hydric soils was developed for use in areas containing RPM (F21 - Red Parent Material). The F21 - Red Parent Material hydric soil field indicator requires (USDA-NRCS 2017):

A layer derived from red parent materials that is at least 10 cm (4 in.) thick, starting at a depth ≤ 25 cm (10 in.) from the soil surface with a [Munsell] hue of 7.5YR or redder. The matrix has a value and chroma greater than 2 and less than or equal to 4. The layer must contain 10% or more depletions and/or distinct or prominent concentrations occurring a soft masses or pore linings. Redox depletions should differ in color by having:
  1. a.

    a minimum difference of one value higher and one chroma lower than the matrix, or

     
  2. b.

    value of 4 or more and chroma of 2 or less.

     

The F21 - Red Parent Material hydric soil field indicator is approved for use in portions of the mid-Atlantic, New England, and Appalachian mountains including Major Land Resource Area (MLRA) 127 of Land Resource Region (LRR) N, MLRA 145 of LRR R, and MLRAs 147 and 148 of LRR S. Notably, the indicator has also been approved for testing across the United States in all soils derived from RPM (USDA-NRCS 2017). As a result, the F21 – RPM indicator can be applied in any soil identified as containing problematic RPM. To that end the F21 - Red Parent Material hydric soil field indicator user notes incorporate the CCPI concept, limiting application to soils in which problematic RPM (i.e., CCPI <30) has been documented using laboratory testing. Additionally, current guidance highlights examples of derivative problematic RPM soils (e.g., residuum in the Piedmont Province Triassic lowlands, Paleozoic red beds of the Appalachian Mountains) promoting application within those areas.

Despite the advances in laboratory techniques and field indicator development related to problematic RPM, several obstacles continue to restrain utilization of F21 - Red Parent Material. First, field practitioners report limited experience and comfort differentiating between problematic RPM and other red soils. Second, prior to the current study, CCPI analysis was utilized on a case by case basis, precluding development large scale problematic RPM mapping. As a result, current guidance lacks a comprehensive list of confirmed problematic RPM locations throughout the country. For these reasons, field staff report a general reluctance to utilize F21 - Red Parent Material when making wetland determinations despite the persistence of problems related to RPM (Berkowitz 2011b).

In response, the USACE and the Pedology Research Laboratory at The University of Maryland, in cooperation with the United States Department of Agriculture – Natural Resources Conservation Service (USDA-NRCS) and Kellogg Soil Survey Laboratory (KSSL), began a nationwide soil mapping project to identify areas containing problematic RPM in support of the application of F21 - Red Parent Material. Study objectives include: 1) evaluating soils suspected to be associated with problematic RPM using CCPI analysis across a wide variety of soil and geologic settings, 2) correlating CCPI results with soil/geologic map units using spatial datasets, and 3) developing national and regional guidance maps for recommended application of F21 - Red Parent Material to improve hydric soil (and therefore wetland) identification across the country. Select examples of the geologic origin of problematic RPM are also provided within each section along with guidance on the application of study results. A comprehensive report on the geology and soils related to problematic RPM is provided in Mack (2018).

Methods

A national effort was coordinated between soil and wetland scientists from federal agencies, state/local agencies, universities, and the private sector. Letters of invitation were sent to all USDA-NRCS MLRA regional offices and USACE district offices to solicit participation among scientists and/or field personnel familiar with the RPM phenomenon to participate in the project. A cooperative arrangement was also established with KSSL permitting access to archived soil samples and associated data. The project was further promoted at conferences organized by the Soil Science Society of America and the National Cooperative Soil Survey. These efforts resulted in the collection and/or volunteer submission of >1100 soil samples from the contiguous United States over a 1.5 year period. Supplemental figures identify soil sampling and archival locations used to develop guidance maps.

All submitted soil samples were derived from geologic formations and/or parent material(s) potentially associated with problematic RPM. As a result, CCPI soils analysis could be correlated with geological data in the mapping phases of the project. Sampling included all red soils suspected of problematic RPM, irrespective of the presence of wetland conditions or field indicators of hydric soils (including F21 – Red Parent Material). This approach utilized the local knowledge of field professionals to obtain a broad representation of soils, as well as attempting to capture all possible inclusions of hydric soils that can occur in soil map units dominated by well drained soils to map the entire possible extent of problematic RPM. Based on the reports of potential RPM soils and their parent materials from participating scientists, additional soils were requested for analyses from the KSSL.

Project participants provided a 500 cm3 sample from each horizon to a depth of 1 m to reflect properties of the entire soil profile and/or the soil’s parent materials to the extent possible. Basic soil descriptions, containing horizon names, depths, colors, field textures, and the presence, contrast, and abundance of any redoximorphic features, were requested to accompany samples as described in Vasilas and Berkowitz (2016). Finally, site location (GPS coordinate), soil series, and any geological context (e.g., formation name, time period, rock type, etc.) were also requested.

All CCPI analyses followed methods outlined in Rabenhorst and Parikh (2000). Soils were dried, crushed, and sieved using a 2 mm (#10) sieve. Two to three horizons (one from the surface, subsurface, and deeper subsurface) from each profile underwent CCPI analyses. Soil colors were measured using a Konica-Minolta digital colorimeter, with Munsell hue, value, and chroma recorded to the 0.1 unit. Soil color was measured on each sample under three different conditions: 1) after saturation with citrate buffer solution; 2) after treatment with citrate buffer solution and sodium dithionite at room temperature (25 °C) for 1 h; and 3) after treatment with citrate buffer solution and sodium dithionite at 80 °C for 4 h. Based on measured color data, a CCPI value was calculated for each sample to document if the soil was problematic RPM, non-problematic, or potentially problematic as described above. The mean CCPI value for all horizons samples was used to assign a single designation to each sample location. Some soils in which problematic RPM was positively identified (24 of >450 pedons) displayed CCPI results that differed by horizon; utilizing the mean value for each pedon may represent a potential limitation of this approach. Statistical testing evaluating difference in CCPI values between problematic, non-problematic, and potentially problematic RPM soils utilized one-way analysis of variance (ANOVA; α = 0.05) following testing for normality (Shapiro Wilk test) and homogeneity of variance (Levene’s test; SPSS IBM, Inc. Version 20).

Following CCPI analysis, problematic RPM samples were linked with associated soil series and/or geologic formations using USDA-NRCS Official Series Descriptions (OSDs), Block Diagrams, Series Extent Maps, other available resources, as well as local knowledge from project participants. Specifically, a list of soil series associated with problematic RPM was generated using the following criteria: series with direct CCPI verification, published literature documenting problematic RPM, the OSD indicated geographic association with a CCPI verified series, or the soil series was derived from a USDA-NRCS Block Diagram composed of CCPI verified materials. Notably, feedback from experienced soil scientists familiar with the local distribution of problematic RPM was utilized to further refine the series list. Following the generation of the problematic RPM soil series lists, series names were joined to both the USDA-NRCS Digital Gridded U.S. General Soil Map (gSTATSGO2) and Gridded Soil Survey Geographic (gSSURGO) map units as found in the component tables for the map unit records using ArcGIS 10.4 software.

Additionally, parent materials and geological units associated with problematic RPM soil series were identified for mapping. Similar to the soil series approach described above, submitted samples were linked with geological units (as members, formations, groups, etc.) verified as containing problematic RPM, or those lithologically-associated with verified problematic RPM units. A geological unit was added to the list when: the geological unit was the parent material of a soil series identified as problematic RPM using CCPI, previously published literature identified the geological unit as problematic RPM, the geological unit was identified in the OSD of a verified soil series using CCPI data, the geological unit was associated with a verified problematic RPM series using USDA-NRCS Block Diagram, or the geological unit was mapped and was substantially overlain by a problematic RPM soil map unit in both USDA-NRCS gSTATSGO and gSSURGO databases. The USGS Mineral Science Program’s Integrated Geologic map database for the United States was also utilized to define geologic features. Geologic units identified as problematic RPM were mapped predominantly by formation name within the US Geological Survey’s (USGS) “Preliminary Integrated Geologic Map Databases for the United States” using ArcGIS 10.4 software.

Individual soils map units were identified as problematic RPM if the map unit contained ≥5 % of a problematic RPM soil series, or corresponding geologic unit datasets suggested the presence of problematic RPM parent materials. As a result, national scale problematic RPM guidance maps represent the composite of both soils and geological information supported by CCPI analyses. Regional maps were also generated based on the locations of RPM occurrence across USDA-NRCS LRRs and MLRAs and USACE regional supplements. Draft problematic RPM maps were sent to affected USDA-NRCS MLRA offices and USACE district offices to solicit comment and feedback from field personnel familiar with local soil conditions. Following editing and comment response based upon user feedback, final guidance maps were generated for recommended application of field indicator F21 - Red Parent Material.

Results and Discussion

National Overview

More than 1100 individual soil samples, collected from >450 geographic locations within the contiguous United States, were analyzed for CCPI to investigate the spatial distribution of problematic RPM. Within the dataset, 51% of soils were characterized by CCPI values consistent with problematic RPM properties (i.e., color change resistance; CCPI <30), 19% displayed some resistance to color change (i.e., potential problematic RPM; CCPI 30–40), and 30% consisted of soils were identified as non-problematic RPM (CCPI >40). Where present, problematic RPM soils displayed mean CCPI (± standard deviation) of 19 ± 6.1, significantly lower (p < 0.001) than non-problematic soils (CCPI = 66 ± 35), and potentially problematic (CCPI = 36 ± 4.0) soils (p < 0.001) examined. Similar statistical differences were found in each problematic RPM region discussed below. As a result, approximately 745 soil series and associations linked with 270 geologic formations displayed CCPI values consistent with potential problematic RPM conditions. Problematic RPM soils were associated with a wide variety of parent materials, with residual (31%), alluvial (28%), and till (23%) sources most commonly observed. A variety of colluvial, lacustrine, erosional deposits and mixed parent materials also exhibited problematic RPM properties. Notably, despite the wide variety of parent materials observed, all samples identified as problematic RPM soils across the national dataset were associated with parent materials derived from red bed formations, as well as glacial, alluvial, and colluvial transported materials derived from red bed formations. Red beds include detrital, siliciclastic sedimentary rocks or sequences (e.g., conglomerates, sandstones, siltstones, shales) in which ≥60% of the total stratum displays red pigments resulting from ferric oxides, predominantly hematite. For more information on the characteristics, origins, or classification of red beds, see Krynine (1949); Van Houten (1973); Turner (1980); and Bigham et al. (1993).

Four problematic RPM regions have been identified where F21 - Red Parent Material application is recommended based on the occurrence of problematic RPM across various USACE regional supplement areas and USDA-NRCS LRRs (Fig. 1): Northeast and Mid-Atlantic, Great Lakes, South-Central, Desert Southwest and Western Mountains. The following section provides detailed maps and describes CCPI results within each of these four problematic RPM regions, yielding insight into the soil series and geologic formations identified, and problematic RPM locations within USACE regional supplements, USDA-NRCS LRRs and MLRAs. Tables provide lists of geologic features and soil series linked with problematic RPM. Guidance for the application of study results to identify hydric soils in areas containing problematic RPM is also discussed. Supplementary maps are also provided, displaying sampling locations within each region (Figs. S1-S5).
Fig. 1

National guidance map for recommended application of the F21 - Red Parent Material hydric soil field indicator in the United States. Red areas indicate locations with soils and geological formations where problematic RPM potentially occur

Northeast and Mid-Atlantic

Over 100 sample locations were analyzed for CCPI from the Northeast and Mid-Atlantic problematic RPM region confirming problematic RPM in two USACE regional supplement areas, five LRRs, and 14 MLRAs (Table 1; Fig. 2). Within the Northeast and Mid-Atlantic 76 locations contained problematic RPM (mean CCPI ± standard deviation = 20 ± 5.9), 19 locations were non-problematic (CCPI = 50 ± 11) and 18 exhibited potential color change resistance (CCPI = 35 ± 4.2). Parent materials displaying problematic RPM were derived from till (31%), alluvium (26%), residuum (24%), with colluvial and mixed deposits also present. The Northeast and Mid-Atlantic encompasses considerable topographic, climatic, and geologic diversity, with problematic RPM stretching across portions of thirteen U.S. states. Generally, the geology of the problematic RPM region is differentiated between northern (USACE Northcentral and Northeast regional supplement area) and southern (USACE Eastern Mountains and Piedmont regional supplement area) portions by the southernmost extent of Pleistocene glaciations (Mack 2018; USDA-NRCS 2006). Within the Northeast and Mid-Atlantic problematic RPM region, four distinctive groups (Fig. 2) of soils and parent materials have been identified including soils derived from: 1) Paleozoic-aged, sedimentary red beds of Appalachia; 2) glacial deposits of the Glaciated Allegheny Plateau and Catskill Mountains; 3) till and (glacio)lacustrine deposits of the Ontario-Erie Plain and Finger Lakes; and 4) sedimentary rocks of the Newark Supergroup. These areas are characterized by residual and glacial soils derived from dark, red shales, siltstones, and sandstones laid down in passive continental margins during the formation of the current Appalachian mountain system (i.e. the Paleozoic “Red Beds” of Appalachia; the Glaciated Allegheny Plateau and Catskill Mountains; and the Ontario-Erie Plain and Finger Lakes) and in low lying basins formed during the breakup of supercontinent Pangea (i.e. the Newark Supergroup). Specific soil series and geologic formations associated with each portion of the Northeast and Mid-Atlantic problematic RPM region are provided in Tables 2, 3, 4 and 5.
Table 1

USACE regional supplement areas, LRRs, and MLRAs within the Northeast and Mid-Atlantic RPM region where application of the F21 - Red Parent Material field indicator is recommended

USACE region

Land Resource region (LRR)

Major Land Resource Area (MLRA)

Northcentral and Northeast

L – Lake States Fruit, Truck Stop, and Dairy region

101 – Ontario-Erie and Finger Lakes

R – Northeastern Forage and Forest Region

140 – Glaciated Allegheny Plateau

142 – St. Lawrence-Champlain Plain

144A – New England and Eastern New York Upland

145 – Connecticut Valley

Eastern Mountains and Piedmont

N – East and Central Farming and Forest Region

124 – Western Allegheny Plateau

125 – Cumberland Plateau

126 – Central Allegheny Plateau

127 – Eastern Appalachian Ridges and Valleys

128 – Southern Appalachian Ridges and Valleys

130A – Northern Blue Ridge

P – South Atlantic and Gulf Slope Cash Crops, Forest, and Livestock Region

136 – Southern Piedmont

S – Northern Atlantic Slope Diversified Farming Region

147 – Northern Appalachian Ridges and Valleys

148 – Northern Piedmont

Fig. 2

Guidance map for recommended application of the F21 - Red Parent Material field indicator in the Northeast and Mid-Atlantic RPM region. Red areas indicate locations with soils and geological formations where problematic RPM potentially occur

Table 2

Geological formations and soil series identified as potential problematic RPM that are associated with the Paleozoic red beds of Appalachia

Geological Formation(s)

Soil Series

Bloomsburg Formation

Foreknobs Formation

Albrights

Meckesville

Bloomsburg Red Beds

Glenshaw Formation

Alcoa

Moshannon

Bluefield Formation

Greenbriar Formation

Allenwood

Neubert

Bluestone Formation

Greenbriar Group

Basher

Peabody

Casselman Formation

Greene Formation

Belpre

Pipestem

Catskill Formation

Hampshire Formation

Birdsboro

Raritan

 Beaverdam Run Member

Hinton Formation

Calvin

Red Hills

 Berry Run Member

Holston Formation

Cateache

Senecaville

 Clarks Ferry Member

Huntley Mountain Formation

Coghill

Sensabaugh

 Duncannon Member

Juniata Formation

Corryton

Steekee

 Irish Valley Member

Maccrady Shale

Craigsville

Summitville

 Long Run Member

Maccrady Formation

Gallia

Tellico

 Packerton Member

Mauch Chunk Formation

Hackers

Ungers

 Poplar Gap Member

Mauch Chunk Group

Hustontown

Upshur

 Sawmill Run Member

McKenzie Formation

Leck Kill

Vandalia

 Sherman Creek Member

Monongahela Formation

Lehew

Vandergrift

 Towamensing Member

Monongahela Group

Linden

Vincent

 Walcksville Member

Pennington Formation

Kedron

Watson

Chemung Formation

Pennington Group

Klinesville

Woodsfield

Clinton Group

Rose Hill Formation

Madsheep

 

Conemaugh Formation

Slide Mountain Formation

  

Conemaugh Group

Washington Formation

  

Dunkard Group

Waynesburg Formation

  
Table 3

Geological formations and soil series identified as potential problematic RPM that are associated with the Glaciated Allegheny Plateau and the Catskill Mountains area

Geological Formation(s)

Soil Series

Catskill Formation

Bash

Monguap

 Beaverdam Run Member

Barbour

Morris

 Berry Run Member

Basher

Norchip

 Clarks Ferry Member

Cadosia

Norwich

 Duncannon Member

Cheshire

Onteora

 Irish Valley Member

Elka

Oquaga

 Long Run Member

Halcott

Suny

 Packerton Member

Hawksnest

Tor

 Poplar Gap Member

Gretor

Trestle

 Sawmill Run Member

Lackawanna

Tunkhannock

 Sherman Creek Member

Lewbeach

Vly

 Towamensing Member

Linden

Wellsboro

 Walcksville Member

Maplecrest

Willowemoc

Slide Mountain Formation

Menlo

Wyoming

Table 4

Geological formations and soil series identified as potential problematic RPM as associated with the Ontario-Erie Plain and Finger Lakes area

Geological Formation(s)

Soil Series

Clinton Group

Alton

Lockport

Lockport Group

Appleton

Odessa

Medina Group

Barre

Ontario

Queenston Formation/Shale

Cayuga

Ovid

Rondout Formation

Cazenovia

Romulus

Salina Group

Churchville

Schoharie

 Camillus Formation

Hilton

 

 Syracuse Formation

Lairdsville

 

 Vernon Formation

Lakemont

 
Table 5

Geological formations and soil series identified as potential problematic RPM that are associated with basins of the Newark Supergroup

Basin(s)

Geological Formation(s)

Soil Series

Harford, Deerfield, Northfield

East Berlin Formation

Bash

Ludlow

Mount Toby Formation

Berlin

Manchester

New Haven Arkose

Branford

Menlo

Portland Arkose

Brownsburg

Penwood

Shuttle Meadow Formation

Cheshire

Watchaug

Sugarloaf Formation

Ellington

Wethersfield

Turner Falls Sandstone

Harford

Wilbraham

Holyoke

Yalesville

Newark

Boonton Formation

Abbottstown

Knauers

Brunswick Formation

Arendtsville

Lamington

Feltville Formation

Athol

Lansdale

Hammer Creek Formation

Bermudian

Landsdowne

Lockatong Formation

Birdsboro

Lawrenceville

Passaic Formation

Boonton

Lewisberry

Raritan Formation

Bowmansville

Lucketts

Stockton Formation

Brecknock

Morven

Towaco Formation

Bucks

Nixon

Gettysburg

Gettyburg Conglomerate

Buckingham

Norton

Gettysburg Formation

Chalfont

Pascask

 Heidlersburg Member

Croton

Penn

Gettysburg Shale

Doylestown

Quakertown

Hammer Creek Conglomerate

Dunellen

Raritan

Hammer Creek Formation

Exway

Readington

New Oxford Conglomerate

Greenbelt

Reaville

New Oxford Formation

Haledon

Rowland

Joanna

Springwood

Klinesville

 

Culpeper, Barboursville, Scottsville

Newark Supergroup – conglomerates, sandstones, siltstones, shales, mudstones

Aden

Leedsville

Albano

Manassas

Arcola

Nestoria

Ashburn

Oatlands

Brentsville

Ott

Calverton

Panorama

Catlett

Rapidan

Clover

Sudley

Dulles

Sycoline

Kelly

Totier

Crowburg, Wadesboro, Ellerbe, Sanford, Durham, Davie County, Dan River, Danville, Scottsburg, Randolph, Roanoke Creek, Briery Creek, Farmville

Chatham Group

Ayersville

Meadows

Cow Branch Formation

Belews Lake

Mooshaunee

Cumnock Formation

Brickhaven

Peakin

Dan River Group

Carbonton

Pinkston

Pekin Formation

Claycreek

Pinoka

Pine Hall Formation

Creedmoor

Polkton

Sanford Formation

Easthamlet

Sheva

Stoneville Formation

Granville

Spray

Hallison

Stoneville

Hasbrouck

Straightstone

Hornsboro

Wadesboro

Lackstown

Warminster

Leaksville

White Store

Mayodan

Wolftrap

Great Lakes

A total of 218 soil samples from 78 sites were analyzed for CCPI from the Great Lakes problematic RPM region. Fifty-six locations contained problematic RPM (mean CCPI ± standard deviation = 21 ± 6.3), 7 locations were non-problematic (CCPI = 47 ± 5.3) and 15 exhibited potential color change resistance (CCPI = 35 ± 6.6). Soil materials in the Great Lakes problematic RPM region are most commonly derived from Pleistocene-aged, glacial deposits (>67%) that stretch across portions of three U.S. states that include portions of the Northcentral and Northeast regional supplement area and two LRRs (Table 6).
Table 6

USACE regional supplement areas, LRRs, and MLRAs within the Great Lakes RPM region where application of the F21 - Red Parent Material hydric soil field indicator is recommended

USACE region

Land Resource Region (LRR)

Major Land Resource Area (MLRA)

Northcentral and Northeast

K – Northern Lake States Forest and Forage Region

57 – Northern Minnesota Gray Drift

88 - Northern Minnesota Glacial Lake Basins

89 – Wisconsin Central Sands

90A – Wisconsin and Minnesota Thin Loess and Till, Northern Part

90B - Wisconsin and Minnesota Thin Loess and Till, Southern Part

91A – Central Minnesota Sandy Outwash

91B – Wisconsin and Minnesota Sandy Outwash

92 – Superior Lake Plain

93A – Superior Stony and Rocky Loamy Plains and Hills, Western Part

93B - Superior Stony and Rocky Loamy Plains and Hills, Eastern Part

94A – Northern Michigan and Wisconsin Sandy Drift

94B – Michigan Eastern Upper Peninsula Sandy Drift

94C – Michigan Northern Lower Peninsula Sandy Drift

94D –Northern Highland Sandy Drift

95A – Northeastern Wisconsin Drift Plain

95B – Southern Wisconsin and Northern Illinois Drift Plain

L – Lake States Fruit, Truck Crop, and Dairy Region

96 – Western Michigan Fruit Belt

98 – Southern Michigan and Northern Indiana Drift Plain

99 – Erie-Huron Lake Plain

In general, the Great Lakes RPM region is characterized by dark red, Wisconsinan-aged glacial deposits distributed by the advance and retreat of glacial lobes of the Laurentide ice sheet. These glacial deposits originated from red sedimentary rocks of the Superior Basin and some possible Paleozoic/Mesozoic rocks of the Michigan basin. A full reporting of the Great Lakes geologic origin is beyond the scope of the current manuscript, which focuses on linking problematic RPM distribution with soil series data to improve approaches to hydric soil identification in red soils. However, a comprehensive discussion of geologic features associated with the Great Lakes problematic RPM region is provided in Mack (2018). To facilitate identification of problematic RPM, Fig. 3 as well as Tables 7, 8 and 9 link areas of verified problematic RPM soils with underlying geologic formations and soil series.
Table 7

Geological formations and soil series identified as potential problematic RPM associated with the Superior Lobe

Geological Formation(s)

Soil Series

Bayfield Group

Adolph

Ellsburg

Matchwood

Poskin

 Chequamegon Sandstone

Ahmeek

Escanaba

McQuade

Richford

 Devil’s Island Sandstone

Aldenlake

Fayal

Mecan

Robago

 Orienta Sandstone

Chippewa Lobe Till

Algonquin

Fence

Mesaba

Rockland

Copper Falls Formation

Allendale

Finland

Michigamme

Rockmarsh

Fond du Lac Formation

Amery

Flak

Milaca

Ronneby

Hinckley Sandstone

Amnicon

Flink

Millward

Rosholt

Jacobsville Formation

Anigon

Flintsteel

Misery

Rudyard

Jacobsville Sandstone

Annalake

Forbay

Mishwabic

Sanborg

Keweenaw Bay Lobe Till

Anton

Freeon

Miskoaki

Santiago

Langlade Lobe Till

Arcadian

Freer

Montreal

Schaat

Lincoln Formation

Arnheim

Froberg

Mooseline

Creek

Michigamme Lobe Till

Ashwabay

Gaastra

Moquah

Schisler

Miller Creek Formation

Augustana

Garlic

Mora

Schweitzer

Ontonagon Lobe Till

Automba

Gay

Morganlake

Scoba

Oronto Group

Baden

Giese

Munising

Sconsin

 Copper Head Conglomerate

Badriver

Glendenning

Negwegon

Sedgewick

 Freda Sandstone

Barto

Gogebic

Nemadji

Shag

 Nonesuch Shale

Bergland

Gratiot

Net

Skanee

River Falls Formation

Big Iron

Greenstone

Newood

Spear

Superior Lobe Till

Bigisland

Gull Point

Newot

Sporley

Trade River Formation

Borea

Haugen

Nonesuch

Springport

Wisconsin Valley Lobe Till

Brennyville

Haybrook

Normanna

Springstead

Brill

Hegberg

Ocqueoc

St. Francis

Bushville

Hellwig

Odanah

Sturgeon

Canosia

Herbster

Ogilvie

Superior

Carp Lake

Hermantown

Oldman

Tipler

Cebana

Hibbing

Omega

Toimi

Chequamegon

Hulligan

Ontonagon

Trap Falls

Chetek

Jewett

Oronto

Trimountain

Chippewa

Karlin

Ossmer

Tula

Harbor

Kellogg

Otterholt

Turpela

Clemens

Keweenaw

Paavola

Twig

Copper

Kingsley

Padus

Wabeno

Harbor

Lac La Belle

Padwood

Wahbegon

Cornucopia

Langola

Palmers

Waiska

Cress

Lerch

Parent

Wakefield

Cromwell

Loggerhead

Payseor

Watab

Culver

Magnor

Pearl

Watton

Dairyland

Mahtowa

Pelkie

Worchester

Dechamps

Majestic

Pemene

Wormet

Denomie

Makwa

Pence

Worwood

Dinham

Manido

Pesabic

Yalmer

Duluth

Manistee

Peshekee

 

Dusler

Manitowish

Pickford

 

Eaglebay

 

Porkies

 

Eldes

 

Portwing

 
Table 8

Geological formations and soil series identified as potential problematic RPM that are associated with the Kewaunee formation

Geological Formation(s)

Soil Series

Bayfield Group

Angelica

Moquah

Tipler

 Chequamegon Sandstone

Banat

Mosel

Wabeno

 Devil’s Island Sandstone

Bonduel

Moshawquit

Waymor

 Orienta Sandstone

Borth

Nadeau

Winneconne

Fond du Lac Formation

Briggsville

Omena

Worchester

Green Bay Lobe Till

Cress

Omro

Wormet

Hinckley Sandstone

Cunard

Onaway

Wyocena

Holy Hill Formation

Elderon

Oshkosh

Zittau

 Horicon Member

Emmert

Ossineke

Zurich

 Liberty Grove Member

Escanaba

Pearl

 

Kewaunee Formation

Fairport

Pecore

 

 Branch River Member

Fence

Peebles

 

 Chilton Member

Frechette

Pelkie

 

 Florence Member

Gaastra

Pemene

 

 Glenmore Member

Hortonville

Perote

 

 Kirby Lake Member

Kaukauna

Peshekee

 

 Middle Inlet Member

Kennan

Peshtigo

 

 Ozaukee Member

Keshena

Poy

 

 Silver Cliff Member

Kewaunee

Poygan

 

 Two Rivers Member

Keweenaw

Rabe

 

 Valders Member

Kiva

Richford

 

Jacobsville Formation

Kolberg

Rosholt

 

Jacobsville Sandstone

Longrie

Shawano

 

Oronto Group

Manawa

Solona

 

 Copper Head Conglomerate

Manistee

Stambaugh

 

 Freda Sandstone

Mecan

Symco

 

 Nonesuch Shale

Montello

Tilleda

 
Table 9

Geological formations and soil series identified as potential problematic RPM that are associated with the Michigan Basin

Geological Formation(s)

Soil Series

Bayfield Group

Algonquin

Morganlake

 Chequamegon Sandstone

Allendale

Nadeau

 Devil’s Island Sandstone

Angelica

Negwegon

 Orienta Sandstone

Annalake

Nunica

Fond du Lac Formation

Bergland

Ocqueoc

Hinckley Sandstone

Biscuit

Oldman

Ionia Formation

Bonduel

Omena

Jacobsville Formation

Cunard

Onaway

Jacobsville Sandstone

Engadine

Ontonagon

Jurassic Red Beds

Fairport

Ossineke

Oronto Group

Fence

Pelkie

 Copper Head Conglomerate

Fibre

Pickford

 Freda Sandstone

Gaastra

Poy

 Nonesuch Shale

Gay

Rudyard

Queenston Formation

Graveraet

Solona

Salina Group

Karlin

Sporley

Kellogg

Springport

Kiva

Superior

Longrie

Waiska

Manistee

 
Areas containing problematic RPM are differentiated across the landscape based on their association with distinct tongues or lobes created during advances and retreats of the Laurentide ice sheets (Lusardi 1997). As a result, problematic RPM soils deposited by these glacial fronts, occur on a wide variety of glacial landforms (moraines, drumlins, outwash plains, lake beds). Three distinctive groups of problematic RPM soils and parent materials were identified in the Great Lakes, including soils derived from red glacial deposits associated with: the Superior Lobe; the Kewaunee formation; and the northern portion of the Michigan Basin (Fig. 3). A number of subordinate lobes further subdivide the area, with multiple episodes of glaciation complicating the geologic history of the area, with each glacial advance and retreat introducing new mixtures of materials including potentially problematic RPM across the landscape. As a result, the extent of potential problematic RPM in the Great Lakes (Fig. 3) must be linked with other factors prior to the identification of hydric soils (and wetlands). See the application discussion below for details on the recommended use of problematic RPM maps for additional guidance. Further, many areas exhibit problematic RPM at depths below a mantle of recently deposited soil materials that may or may not contain materials resistant to color change. The authors observed this during several field site visits in which the problematic RPM (and field indicator F21 – RPM) was encountered at depths ≥20 cm below the soil surface. Accumulations of organic materials (i.e. histic epipedons) or other non-problematic soils that rapidly develop redoximorphic features may also overlay problematic RPM deposits. In these cases, other field indicators of hydric soils may be useful in delineating hydric soils and associated wetland features.
Fig. 3

Guidance map for recommended application of the F21 - Red Parent Material field indicator in the Great Lakes RPM region. Red areas indicate locations with soils and geological formations where problematic RPM are possible

South-Central

A total of 300 soil samples from 148 sites underwent CCPI from the South-Central problematic RPM region, resulting in identification of problematic RPM in 28 MLRAs across eight LRRs. Of those samples, 27% exhibited problematic RPM characteristics (CCPI = 26 ± 4.9), 29% displayed some color change resistance (CCPI = 36 ± 4.6), and 43% were non-problematic (CCPI = 58 ± 19). Where present, problematic RPM mostly occurred in soils derived from alluvial and residual parent materials.

Problematic RPM predominantly occurred within the USACE Great Plains and Atlantic and Gulf Coast Plain regional supplement areas, with small areas also found in the Midwest and the Eastern Mountains and Piedmont areas (Fig. 4; Table 10). Problematic RPM occurred across parts of central Texas, Oklahoma, and southern Kansas. Additionally, major rivers and tributary networks rivers transported problematic RPM materials into the alluvial valleys of Arkansas and Louisiana. The South Central problematic RPM region is characterized mostly by residual and alluvial soils derived from Permian-aged bedrock of the Great Plains (i.e. the Central Red Bed Plains), and recent alluvial deposits of the Red, Brazos, and other rivers in southern parts of the Coastal Plain physiographic province (i.e. Central Red Bed Plains Alluvium). Problematic RPMs in the South-Central group vary west to east as conditions shift from the drier, bedrock-controlled portions of the Great Plains to the wetter, thick alluvial deposits overlying the Coastal Plain.
Fig. 4

Guidance map for recommended application of the F21 - Red Parent Material field indicator in the South-Central RPM region. Red areas indicate locations with soils and geological formations where problematic RPM are possible

Table 10

USACE regional supplement areas, LRRs, and MLRAs within the South-Central RPM region where application of the F21 - Red Parent Material hydric soil field indicator is recommended

USACE region

Land Resource Region (LRR)

Major Land Resource Area (MLRA)

Great Plains and Midwest

H – Central Great Plains Winter Wheat and Range Region

78A – Rolling Limestone Prairie

78B – Central Rolling Red Plains,

78C – Central Rolling Red Plains,

80A – Central Rolling Red Prairies

80B - Texas North-Central Prairies

I – Southwest Plateaus and Plains Range and Cotton Region

81B – Edwards Plateau, Central Part

81C – Edwards Plateau, Eastern Part

82A – Texas Central Basin

J – Southwestern Prairies Cotton and Forage Region

82B – Wichita Mountains

84A – North Cross Timbers

84B – West Cross Timbers

84C – East Cross Timbers

85 – Grand Prairie

86A&B – Texas Blackland Prairie

87A&B – Texas Claypan Area

M – Central Feed Grains and Livestock Region

112 – Cherokee Prairies

Eastern Mountains and Piedmont

N – East and Central Farming and Forest Region

118A – Arkansas Valley and Ridges, Eastern Part

118B – Arkansas Valley and Ridges, Western Part

Atlantic and Gulf Coast Plain

O – Mississippi Delta Cotton and Feed Grains Region

131A – Southern Mississippi River Alluvium

131B – Arkansas River Alluvium

131C – Red River Alluvium

Atlantic and Gulf Coast Plain

P – South Atlantic and Gulf Slope Cash Crops, Forest,

133B – Western Coastal Plain

134 – Southern Mississippi Valley Loess

and Livestock Region

135B – Cretaceous Western Coastal Plain

T – Atlantic and Gulf Coast Lowland Forest and Crop Region

150A - Gulf Coast Prairies

150B – Gulf Coast Saline Prairies

Problematic RPM in the Great Plains typically occurs as Permian-aged, red bed formations found on gently rolling plains and prairies dissected by current and ancient stream terraces in the north, and more eroded plateau areas with deeply entrenched streams and rivers in the south. The RPM soils in these areas are often shallow, overlying the red-colored bedrock. In the Atlantic Gulf Coast Plain, RPM soils are derived from red-colored alluvial deposits of major river systems that drain the Permian red beds described above. These alluvial soils occur on terraces, floodplains, lowlands, and deltas along major river systems. Minor RPM areas are also possible in small portions of the USACE Midwest and Eastern Mountains regional supplement areas, where RPM is associated with river systems transporting problematic RPM materials.

Although problematic RPM and their associated soils are extensive in the portions of the South Central United States, much of the area exhibits an ustic soil moisture regime, limiting the extent of hydric soils. Nevertheless, Permian red beds provide the source rocks of RPM soils stretching across several states through alluvial transport. As a result, the F21 – Red Parent Material may be useful in identifying hydric soils in landscape positions where water accumulates and wetlands are likely to occur as well as in aquic portions of southeastern Texas and Louisiana where wetlands are more common (U.S. Army Corps of Engineers 2010a). To facilitate identification of problematic RPM in a field setting, Tables 11 and 12 link areas of verified problematic RPM soils with underlying geologic formations and soil series.
Table 11

Geological formations and soil series identified as potential problematic RPM within the Central Red Bed Plains

Geological Formation(s)

Soil Series

Admiral Formation

Marlow Formation

Altus

Foard

Lugert

Roark

Archer City Formation

 Doe Creek Lentil

Arnett

Frankirk

Lutie

Ruella

Bear Mountain Formation

 Verden Sandstone Lentil

Ashport

Gaddy

Madge

Rups

  

Aspermont

Gageby

Mangum

Sagerton

Big Basin Formation

Moran Formation

Aydelotte

Gracemont

Masham

Selman

Bison Formation

Nippewalla Group

Beckman

Gracemore

McKnight

Shrewder

Blaine Formation

Nocona Formation

Bethany

Grainola

McLain

Southside

 Elm Fork Member

Petrolia Formation

Binger

Grandfield

Milan

Spikebox

 Van Vacter Member

Post Oak Conglomerate

Bukreek

Grant

Miles

St. Paul

Cedar Hill Sandstone

Post Oak Formation

Burford

Hardeman

Miller

Stamford

Chickasha Formation

Post Oak Sandstone

Burson

Harrah

Minco

Stoneburg

Clear Fork Formation

Pueblo Formation

Callahan

Hayfork

Mulhall

Teller

Clear Fork Group

Purcell Sandstone

Canadian

Heman

Nash

Tillman

Cloud Chief Formation

Quartermaster Formation

Carey

Hinkle

Nashville

Tilvern

Dockum Group

Rush Springs Formation

Chickasha

Hollister

Newalla

Tipton

Dog Creek Shale

 Weatherford Gypsum Bed

Clairemont

Huska

Nipsum

Treadway

Doxey Formation

 

Clearfork

Ironmound

Noble

Vernon

Doxey Shale

Salt Plains Formation

Cobb

Jamash

Norge

Vinson

Duncan Sandstone

San Angelo Formation

Colorado

Jaywi

Oakley

Wakita

El Reno Group

San Angelo Sandstone

Cordell

Jester

Obaro

Waurika

Elk City Sandstone

Santa Anna Branch Shale

Cornick

Jolly

Oscar

Westola

Elm Creek Formation

Sumner Group

Cosh

Kamay

Ozark

Westill

Fairmont Shale

Talpa Formation

Darsil

Kingco

Paducah

Westview

Flowerpot Shale

Valera Formation

Darnell

Kingfisher

Pawhuska

Wetbeth

Garber Sandstone

Waggoner Ranch Formation

Decobb

Kirkland

Piedmont

Weymouth

Grape Creek Formation

 

Deepwood

Knoco

Pond Creek

Wheatwood

Guadalupian Series

Wellington Formation

Dill

Konawa

Port

Wichita

Hennessey Group

Whitehorse Formation

Dodson

La Casa

Pulaski

Winters

Jagger Bend Formation

Whitehorse Group

Drummond

Lawrie

Quanah

Wisby

Kingman Formation

Wichita Group

Duke

Lawton

Quinlan

Woodward

Kingman Siltstone

Wolfcampian Series

Enterprise

Lebron

Reinach

Yahola

Leuders Formation

 

Easpur

Lela

Renfrow

Yomont

  

Ezell

Littleaxe

Renthin

Zaneis

  

Farry

Lovedale

Retrop

Zellmont

Table 12

Geological formations and soil series identified as potential problematic RPM associated with alluvial deposits dissecting the Central Red Bed Plains

Geological Formation(s)

Soil Series

Arkansas River Alluvium

Canadian River Alluvium

Cimarron River Alluvium

Red River Alluvium

Addielou

Dougherty

Keo

Muldrow

Severn

Armistead

Forbing

Kiomatia

Necessity

Ships

Bastrop

Gaddy

Konawa

Norwood

Solier

Belk

Gallion

Larton

Okay

Sonnier

Billyhaw

Garton

Latanier

Oklared

Sterlington

Bistineau

Glenwild

Lebeau

Perry

Stidham

Bossier

Goodwill

Lela

Portland

Ustibuck

Buxin

Gore

Liddieville

Porum

Wabbaseka

Caplis

Hebert

McGehee

Redlake

Waskom

Caspiana

Hicota

McKamie

Redport

Weswood

Choska

Idabel

Mer Rouge

Rilla

Whakana

Coushatta

Idee

Miller

Rodessa

Yahola

Dardanelle

Kamie

Moreland

Roebuck

Yorktown

Desha

Karma

Morse

Roxana

 

Brazos River Alluvium

Colorado River Alluvium

Apalo

Clemville

Highbank

Oklared

Sumpf

Aquilla

Coarsewood

Hornsby

Paluxy

Surfside

Asa

Colorado

Kopperl

Pledger

Velasco

Bastrop

Decordova

Mangum

Rabbs

Westola

Belk

Gad

Miles

Roetex

Wheatwood

Bergstrom

Gaddy

Miller

Sagerton

Weswood

Brazoria

Gageby

Minwells

Ships

Winters

Churnabog

Gause

Mohat

Smithville

Yahola

Clearfork

Gholson

Norwood

  

Desert Southwest and Western Mountains

A total of 237 soil samples from 97 sites underwent analysis for CCPI from the Desert Southwest and Western Mountains problematic RPM region. Residual deposits accounted for the majority of parent materials associated with problematic RPM soils (>55%), with alluvial deposits (30%) and mixed source materials also present. Problematic RPM soil CCPI results were significantly lower (CCPI = 19 ± 5.6) than potential (CCPI = 34 ± 2.9; p < 0.001) and non-problematic soils (CCPI = 49 ± 10; p < 0.001). As a result, problematic RPM has been identified for recommended use of the F21 – Red Parent Material hydric soil field indicator in 26 MLRAs of five LRRs. These mostly occur within the USACE Arid West and the Western Mountains, Valleys, and Coast regional supplement areas, with minor areas also occurring in portions of the Great Plains regional supplement area (Table 13; Fig. 5).
Table 13

USACE regional supplement areas, LRRs, and MLRAs within the Desert Southwest and Western Mountains RPM region where application of the F21 - Red Parent Material hydric soil field indicator is recommended

USACE region

Land Resource Region (LRR)

Major Land Resource Area (MLRA)

Arid West

D – Western and Irrigated Region

32 – Northern Intermountain Basins

34A – Cool Central Desertic Basins and Plateaus

34B – Warm Central Desertic Basins and Plateaus

35 – Colorado Plateau

36 – Southwest Plateaus, Mesas, and Foothills

38 – Mogollon Transition

41 – Southeastern Arizona Basin and

Range*

42 – Southern Desertic Basins, Plains, and Mountains

Great Plains

G – Western Great Plains and Irrigated Region

61 – Black Hills Foot Slopes

70A – Canadian River Plains and Valleys

70B – Upper Pecos River Valley

70C – Central New Mexico Highlands*

70D – Southern Desert Foothills*

H – Central Great Plains Winter Wheat and Range Region

77A - Southern High Plains, Northern Part*

77B – Southern High Plains, Northwestern Part*

77E – Southern High Plains, Breaks*

77D – Southern High Plains, Southwestern Part*

I – Southwest Plateaus and Plains Range and Cotton Region

81A – Edwards Plateau, Western Part*

81D – Southern Edwards Plateau*

Western Mountains, Valleys, and Coast

D – Western and Irrigated Region

39 – Arizona and New Mexico Mountains

E – Rocky Mountain Range and Forest Region

43B – Central Rocky Mountains

47 – Wasatch and Uinta Mountains

48A – Southern Rocky Mountains*

48B – Southern Rocky Mountain Parks

49 – Southern Rocky Mountain Foothills*

G – Western Great Plains and Irrigated Region

62 – Black Hills

Fig. 5

Guidance map for recommended application of the F21- Red Parent Material field indicator in the Desert Southwest and Western Mountains RPM region. Red areas indicate locations with soils and geological formations where problematic RPM are possible

The Desert Southwest and Western Mountains problematic RPM region encompasses portions of Arizona, Colorado, New Mexico, Texas, South Dakota, Utah, and Wyoming. The problematic RPM in this region occurs across six vastly different physiographic provinces: the Colorado Plateaus, Middle (Central) Rocky Mountains, Southern Rocky Mountains, Wyoming Basin, Basin and Range (Mexican Highland and Sacramento sections), and portions of the Great Plains (Black Hills, Pecos Valley, and Edwards Plateau sections). Soils within the Desert Southwest and Western Mountains problematic RPM region are characterized by residual, colluvial, and alluvial soils derived from dark, red Paleozoic and Mesozoic-aged rocks uplifted and preserved in the regions mountain ranges (i.e. the Middle and Southern Rockies, Black Hills, Arizona and New Mexico Mountains, Wasatch and Uinta Mountains) and the various plateaus, canyons, and gorges (i.e. the Colorado Plateau and Pecos River Valley) associated with those features. Despite the variability in soils observed in area, the terrestrial red beds that produced problematic RPM soils share similar geological origin related to the erosion and deposition of the Ancestral Rocky Mountains (Table 14; Branson 1927; Reeside 1929; Baker et al. 1947; Pipiringos 1968; Lucas et al. 1993; Lucas and Anderson 1998).
Table 14

Geological formations identified as potential problematic RPM within the Desert Southwest and Western Mountains RPM region

Geological Formation(s)

Abo Formation

Curtis Formation

Morrison Formation

Ankareh Formation

Dinwoody Formation

Naco Group

Arapien Formation

Dockum Formation

Navajo Sandstone

Arcturus Formation

Dockum Group

Nugget Sandstone

Artesa Sequence

Dolores Formation

Park City Formation

Artesia Group

Eagle Valley Formation

Pitoikam Formation

 Graysburg Formation

Entrada Formation

Purgatoire Formation

 Seven Rivers Formation

Entrada Sandstone

Quartermaster Formation

 Tansill Formation

Fountain Formation

 

 Queen Formation

  

 Yates Formation

Gardner Canyon Formation

Ralston Creek Formation

Bull Canyon Formation

Glen Canyon Formation

 

Burro Canyon Formation

Glen Canyon Group

Recreation Red Beds

Bursum Formation

Glen Canyon Sandstone

Rudolfo Red Beds

Carmel Formation

Goose Egg Formation

San Rafael Group

Casper Formation

Grand Canyon Supergroup

Satanka Shale

Chinle Group

 Nankoweap Formation

State Bridge Formation

 Chinle Formation

Guadalupian Series

 

 Garita Creek Formation

Gypsum Spring Formation

Spearfish Formation

 Redonda Formation

Ingleside Formation

Summerville Formation

 Rock Point Formation

Hermit Formation

 

 Santa Rosa Formation

Hermit Shale

Sundance Formation

 Shinarump Conglomerate Member

Jelm Formation

Supai Group

Chugwater Formation

Junction Creek Sandstone

Thaynes Formation

Chugwater Group

Kayenta Formation

Wanakah Formation

Chupadera Formation

Lykins Formation

Wingate Sandstone

Cutler Group

Lyons Formation

Woodside Formation

 Cedar Mesa Sandstone

Lyons Sandstone

Woodside Shale

 Cutler Formation

Maroon Formation

Vampire Formation

 Organ Rock Formation

Mahogany Formation

Yeso Formation

 Organ Rock Shale

Moenkopi Formation

Yeso Group

 

Moenave Formation

Zuni Sandstone

The following groups of problematic RPM and their associated soils where the F21 – Red Parent Material field indicator may be applied include: 1) portions of the Western Mountains, Valleys and Coasts regional supplement area and surrounding foothills; 2) the Colorado Plateaus physiographic province (i.e., the Four Corners region); and 3) the Pecos River Valley (Mack 2018). Problematic RPM associated with the Western Mountains, Valleys, and Coast regional supplement area and surrounding foothills (U.S. Army Corps of Engineers 2010b) includes portions of the central and southern Rockies, the Black Hills, the Arizona and New Mexico mountains, and the Wasatch and Uinta mountains (Fig. 5). As noted elsewhere, understanding where red bed formations and associated soil series (Table 15, 16 and 17) are located will help identify hydric soils derived from problematic RPM soils in these areas. While problematic RPM and their associated soils are extensive, the expanse of ustic and aridic soil moisture regimes likely limits the extent of hydric soils. However, the F21 – Red Parent Material may be useful in identifying hydric soils where water accumulates and wetlands are likely to occur across the landscape including riverine, depressional, and groundwater discharge landscape positions.
Table 15

Soil series identified as potential problematic RPM that are associated with the Western Mountains, Valleys, and Coast regional supplement and surrounding foothills

Soil Series

Almy

Gypnevee

Perrypark

Sandark

Tilford

Barnum

Gystrum

Pimsby

Schooner

Tinytown

Bernal

Lamphier

Plome

Scout

Tours

Boyett

Lonetree

Podo

Sinkson

Vale

Chaseville

Miracle

Red Spur

Sixmile

White House

Cheesman

Monticello

Redbank

Southfork

Wycolo

Connerton

Nevee

Redridge

Spearfish

Yahmore

Contention

Neville

Redtom

Swint

 

Fortwingate

Nuffel

Rekrop

Tampico

 

Garber

Palma

Rizno

Thermopolis

 

Gove

Peralta

Rule

Tieside

 
Table 16

Soil series identified as potential problematic RPM that are associated with the Colorado Plateaus

Soil Series

Acree

Epikom

Mack

Monue

Remorris

Tours

Aneth

Fortwingate

Mellenthin

Naplene

Ribera

Wetherill

Arches

Gladel

Mespun

Nuffel

Rizno

Whitecanyon

Arntz

Grassytrail

Mido

Padilla

Robroost

Winkel

Barx

Hadden

Milok

Palma

Sandark

Yahmore

Begay

Hagerman

Mivida

Parkelei

Simel

 

Blackston

Hassell

Moenkopie

Penzance

Strych

 

Brinkerhoff

Hillburn

Mokaac

Plome

Suwanee

 

Burnswick

Jocity

Monogram

Redbank

Tintero

 

Caval

Leanto

Monticello

Regracic

Tobler

 
Table 17

Soil series identified as potential problematic RPM that are associated with Pecos River Valley

Soil Series

Alama

Glenrio

La Lande

Los Tanos

Quay

San Jon

Bernal

Hagerman

Lacita

Montoya

Redona

Tucumcari

Berwolf

Hassell

Lacoca

Newkirk

Regnier

Tuloso

Conchas

Ima

Largo

Palma

Ribera

Walkon

Interestingly, the Permian red beds of the Pecos River Valley are lithologically correlated with strata confirmed in the South-Central problematic RPM region discussed previously, while the Mesozoic red beds are lithologically correlated to those that occur in the Colorado Plateaus and Rocky Mountain systems. Like the red beds of the Central Red Beds Plains, the rock sequences known to contain red beds also grade into sequences dominated by gray, marine-carbonate rocks that are not recognized as problematic RPM. A variety of river systems drain areas characterized by problematic RPM. Therefore, alluvial deposits may be comprised of (or contain) problematic RPM soils. Furthermore, the headwater of the Pecos, Canadian and Cimarron rivers flow across red beds identified as problematic RPM in the Upper Pecos River Valley providing alluvial source materials for problematic RPM soils as they proceed east and south (Mack 2018).

Application of F21 – Red Parent Material for Hydric Soil and Wetland Delineation

The RPM guidance maps, supplemental information on associated geologic features, and soil series lists are designed to aid practitioners in overcoming obstacles in accurately identifying hydric soils derived from problematic RPM. Maps and tables link soil series, geological formations, and parent materials containing problematic RPM with USACE regional supplement areas, LRRs, and MLRAs, allowing users to rapidly identify potential problematic RPM soils through a variety of pathways. For example, problematic RPM can be identified based upon information regarding either soil survey data, soil series identification or geologic formation information within a given location (e.g., USACE Atlantic Gulf Coastal Plain region; LRR T; MLRA 152A).

Notably, the guidance maps developed encompass all areas potentially containing problematic RPM, including both wetland and upland areas. The provided tables are not limited to soils which appear on the hydric soils list or soil series with poorly and very poorly drained designations. As a result, identification of hydric soils requires both the presence of problematic RPM as determined by the maps, geologies, and soil series lists herein, and the conditions outlined in the F21 – Red Parent Material hydric soil field indicator. Further, for an area to be identified as a wetland, areas exhibiting problematic RPM must also display indicators of wetland hydrology and hydrophytic vegetation as required by the procedures outlined in the USACE wetland delineation manual and associated regional supplements. Based on the findings in the current study, a proposal will be made to the National Technical Committee for Hydric Soils to revise the guidance for F21- Red Parent Material application. The revisions will apply the technical criteria of the hydric soil indicator as written, but require either the application of CCPI data or the occurrence of potential problematic RPM soils within one of the problematic RPM regions described herein. This approach will promote the proper application of the F21 – Red Parent Material hydric soil field indicator without requiring laboratory data collection for individual project areas. Additional site specific CCPI data can be collected if problematic RPM soil occurs outside of the current guidance maps, further expanding the available dataset.

The following steps are recommended when users encounter soils containing potential problematic RPM: 1) Determine if the soil occurs in association with a series or geologic feature identified in the maps and tables provided herein. These map and table resources define areas in which application of hydric soil indicator F21 is recommended. This can be accomplished by evaluating the study location using on-site data collection, Web Soil Survey, maps of geologic features, and the comprehensive descriptions of soil-geologic features in problematic RPM regions provided in Mack (2018). 2) Determine if the soil meets the criteria described in hydric soil indicator F21 – Red Parent Material. If the soil meets the requirements of F21 –Red Parent Material and occurs within a verified problematic RPM region, the presence of a hydric soil is confirmed. Alternatively, if the soil occurs outside of the guidance map boundaries, CCPI analysis can verify the presence of problematic RPM. 3) Determine if the location displays indicators of wetland hydrology and hydrophytic vegetation as described in the USACE wetland delineation manual and associated regional supplements. If the requirements of vegetation, and hydrology are documented in conjunction with 1) and 2) above, the presence of a wetland is confirmed.

Despite the collaborative, comprehensive approach utilized within the national mapping project, several important data limitations need to be considered when using RPM guidance maps and tables. Some limitations result from the broad scale of the mapping effort and inherent variability associated with soils and geologic source materials. To date, more than 24,000 soil series have been established nationwide (Rabenhorst 2016), which precludes the possible evaluation of CCPI for each soil series to verify their status as problematic RPM (or not). As a result, it is possible that problematic RPM may exist in other locations and additional CCPI analysis may be needed to confirm the presence of problematic RPM in those areas. Soil series in the potential problematic RPM range (CCPI of 30–40) were also included in RPM guidance maps if the soil series met criteria (provided above) that were utilized to generate lists of potential RPM soil series during the mapping phases of the project. This was done to avoid exclusion of potential problematic RPM associated with materials that displayed some degree of color change resistance. Additionally, RPM guidance maps were generated using the U.S. General Soil Map (STATSGO2) Database, which is designed for mapping purposes on regional, multi-state scales (1:250,000). Thus, map units identified as problematic RPM are intended to reflect areas where problematic RPM may be present, and onsite verification is required prior to application of the F21 – Red Parent Material hydric soil field indicator. Also, areas included in the RPM guidance maps required 5 % or more of a map unit component to contain a soil series identified as potential problematic RPM as defined in the U.S. General Soil Map (STATSGO2) Database. As previously noted, the approach intentionally did not consider other factors relevant to hydric soils (or wetlands) such as drainage class or slope, but sought to encompass all areas where problematic RPM was likely to occur. Similar limitations are related to the geologic datasets and mapping, including discontinuity between states boundaries regarding geologic mapping conventions and other factors.

Future work should focus on refining national RPM guidance maps based upon application of the hydric soil field indicator F21 - Red Parent Material by wetland practitioners and soil scientists. Increased consultation and collaboration with wetland, soil, and geological scientists should also be pursued in areas where problematic RPM has been identified to further correlate soils and geological datasets with problematic RPM at/across state boundaries. This is especially true for areas in the South-Central and Desert Southwest and Western Mountains problematic RPM regions where sample submission was limited compared to other areas. Further research could also incorporate datasets specifically relevant to wetlands to align the maps presented herein with the occurrence of hydric soils developed in problematic RPM. For example, evaluation of the problematic RPM maps using hydric soils lists, drainage class designation, U.S. Fish and Wildlife Service’s National Wetlands Inventory data, and other tools may prove useful at various spatial scales. Also, utilization of higher resolution soils and geological datasets (where available) could further refine results.

Conclusions

Hydric soil field indicator, F21 - Red Parent Material, has been approved for nationwide testing in soils derived from problematic RPM soils that are resistant to redox-induced color changes. The maps and tables provided allow for rapid and defensible application of hydric soil field indicator F21 – Red Parent Material across the United States, whereas the spatial occurrence and extent of problematic RPM soils was previously unknown. As a result, four problematic RPM regions (Northeast and Mid-Atlantic, Great Lakes, South-Central, and Desert Southwest and Western Mountains) were identified for the application of the F21– Red Parent Material hydric soil field indicator. Within each of these problematic RPM regions, diverse groups of soils and parent materials exhibited problematic RPM characteristics, however all problematic RPM areas occurred in association with sedimentary, hematite-rich “red bed” formations, and the recently deposited (alluvial, colluvial, and glacial) materials derived from them. The problematic RPM maps, tables, and supplemental guidance link soil series, geologic formations, and parent materials containing problematic RPM, allowing users to rapidly identify potential RPM soils through a variety of pathways. Based on these findings, revisions to the F21 – Red Parent Material will be proposed recommending either the application of CCPI data or the occurrence of potential problematic RPM soils within one of the problematic RPM regions described herein prior to the use of the indicator. The collaborative effort among universities, agency staff, soil archives, and field practitioners provided for a national scale mapping effort, improving approaches to hydric soil identification and accurate wetland delineation across a large and diverse geographic area.

Notes

Acknowledgements

This work was supported by the USACE Wetland Regulatory Assistance Program (WRAP) administered through the Engineer Research and Development Center, Environmental Laboratory in Vicksburg, MS. We would like to thank all USDA-NRCS, USACE, academic, state agency, and private sector participants who submitted soil samples and comments, and we are particularly indebted to our colleagues Doug Wysocki, Steve Monteith, Michelle Etmund and Amber Shinn at the KSSL in Lincoln, NE for their tremendous support. Without the time, help, and local expertise provided by over 50 individuals, this nationwide collaborative effort would not have been possible.

Supplementary material

13157_2018_1114_MOESM1_ESM.jpg (1.3 mb)
Figure S1 National guidance map for recommended application of the F21 - Red Parent Material hydric soil field indicator in the United States. Red areas indicate locations with soils and geological formations where problematic RPM potentially occur and white circles indicate sampling locations included in the study dataset. (JPG 1336 kb)
13157_2018_1114_MOESM2_ESM.jpg (1.4 mb)
Figure S2 Guidance map for recommended application of the F21 - Red Parent Material field indicator in the Northeast and Mid-Atlantic RPM region. Red areas indicate locations with soils and geological formations where problematic RPM potentially occur and white circles indicate sampling locations included in the study dataset. (JPG 1407 kb)
13157_2018_1114_MOESM3_ESM.jpg (1.1 mb)
Figure S3 Guidance map for recommended application of the F21 - Red Parent Material field indicator in the Great Lakes RPM region. Red areas indicate locations with soils and geological formations where problematic RPM are possible and white circles indicate sampling locations included in the study dataset. (JPG 1165 kb)
13157_2018_1114_MOESM4_ESM.jpg (1.4 mb)
Figure S4 Guidance map for recommended application of the F21 - Red Parent Material field indicator in the South-Central RPM region. Red areas indicate locations with soils and geological formations where problematic RPM are possible and white circles indicate sampling locations included in the study dataset. (JPG 1484 kb)
13157_2018_1114_MOESM5_ESM.jpg (1.8 mb)
Figure S5 Guidance map for recommended application of the F21- Red Parent Material field indicator in the Desert Southwest and Western Mountains RPM region. Red areas indicate locations with soils and geological formations where problematic RPM are possible and white circles indicate sampling locations included in the study dataset. (JPG 1868 kb)

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Copyright information

© The Author(s) 2018

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors and Affiliations

  • Sara C. Mack
    • 1
  • Jacob F. Berkowitz
    • 2
    Email author
  • Martin C. Rabenhorst
    • 1
  1. 1.Department of Environmental Science and Technology, H.J. Paterson HallUniversity of MarylandCollege ParkUSA
  2. 2.US Army Corps of EngineersEngineer Research and Development CenterVicksburgUSA

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