Investigating problematic hydric soils derived from red-colored glacial till in the Hartford

Rift Basin of Connecticut

By

Eric C. Ford

A MAJOR PAPER SUBMITTED IN PARTIAL FULLFILLMENT OF THE REQUIREMENTS

FOR THE DEGREE OF MASTER OF ENVIRONMENTAL SCIENCE AND MANAGEMENT

THE UNIVERSITY OF RHODE ISLAND

December 19, 2014

MAJOR PAPER ADVISOR: Dr. Mark H. Stolt

MESM TRACK: Wetland, Watershed, and Ecosystem Science

ABSTRACT

Hydric soils are one of the three diagnostic environmental characteristics (or factors) of

wetlands. Their unique morphologies, derived from anaerobic biogeochemical processes, are

used by wetland and soil scientists to identify hydric soils in the field. These morphologies are

described in Field Indicators of Hydric Soils in the United States: A Guide for Identifying and

Delineating Hydric Soils (Version 7.0; United States Department of Agriculture, Natural

Resources Conservation Service, 2010). Despite the fact that these hydric soil indicators have

been developed and used nation-wide for nearly 30 years, there remain several “problematic”

soils that do not conform to the current hydric soil morphological paradigm, including those soils

derived from red-colored glacial till in southern New England. These problematic soils can cause

erroneous interpretations that, in turn, can have severe implications relative to land use decisions.

The objectives of this study were to 1) test the utility of a previous (TF2) and existing (F21)

hydric soil indicator for these soils; and, if necessary, 2) make recommendations toward the

development of a region-specific hydric soil indicator for soils derived from red-colored glacial

till in southern New England. Three sites were established within the central lowlands of

Connecticut. A multi-parameter, paired site approach was implemented, following the

requirements of the “National Hydric Soil Technical Standard” (HSTS; National Technical

Committee for Hydric Soils, 2007). Data collected from these sites were combined with

previous, unpublished work completed by the United States Department of Agriculture, Natural

Resources Conservation Service, and the University of Massachusetts, Amherst. Evaluation of

the sites relative to the TF2 and F21 hydric soil indicators revealed that TF2 may be too

conservative for use, while F21 appears too restrictive. The latter is of concern, as it is currently

the only formally accepted indicator for use within the region. Based on soil

i

hydromorphological data collected from the study sites, it appears that the two primary limiting

factors in determining the applicability of TF2 or F21 were related to abundance and contrast of

redoximorphic features. The TF2 abundance requirements (2%) were too low, while the F21

abundance requirements (10%) were too high. In addition, contrast requirements for F21 were

too restrictive and excluded several pedons that met the requirements of the HSTS, but had faint

contrast. We recommend abundance requirements be reduced to 5% and there be no contrast

requirement. This study highlights the difficulties in evaluating soils derived from red-colored

glacial till, and emphasizes the need for wetland and soil scientists to rely on multiple approaches

when evaluating sites within affected areas.

ii

DEDICATION

This paper is dedicated to the love of my life, Ntsa Iab Kha. It is only with your

unwavering support, patience, and love that I have made it through the last two years. I’m

finally all yours!

This paper is also dedicated to my parents. You gave me life, and you gave me love - the

two greatest gifts one could ever receive. I hope I’ve made you proud.

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ACKNOWLEDGEMENTS

A project of such magnitude is very rarely the work of one individual, and this is of no

exception. First off, I would like to express my gratitude and appreciation to my major professor

and advisor, Dr. Mark Stolt. I attribute the level of scholarship found in this paper to your

guidance, wisdom, and knowledge. Thank you for allowing me the opportunity to work with

you; it has been an unbelievable experience.

I would also like to thank Donald Parizek for allowing me to join his red soil “crusade.”

We have spent countless hours in the field together, and you’ve taught me a great deal about

digging in the dirt, particularly red dirt. Thanks for sharing your knowledge. Your name

deserves to be on the cover of this paper just as much as mine.

I would be remiss if I failed to thank all the folks at the USDA-NRCS 12-TOL soil

survey office who helped out with various aspects of the project: Debbie Surabian, for providing

me with the resources and man power necessary to complete field sampling; Jacob Islieb and

Marissa Theve, for your help in the field; Dr. Nels Barrett, for your assistance with vegetation

sampling; and all the Earth Team Volunteers that assisted with various field efforts.

A big thanks goes out to Chelsea Duball, for putting her ulnar collateral ligament at risk

cleaning and sanding IRIS tubes; Tom Pietras, for his assistance with water table monitoring; Dr.

Arthur Gold, for his assistance analyzing water table data; Dr. Leslie “Mickey” Spokas, for

providing us with redox potential data and methods for the Wadsworth Estate site; and finally,

Becca Trietch, for her insightful comments and suggestions during review of this paper.

This project would not be possible without support from Robin MacEwan, David

Cameron, Doug Stewart, and Brooke Barnes at Stantec; Chris Lucas at Lucas Environmental,

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LLC; the New England Hydric Soil Technical Committee; the Society of Soil Scientists of

Southern New England; the 4-H Education Center at Auerfarm; the City of Middletown,

Connecticut; and the Town of Wallingford, Connecticut. Partial funding for this work was

provided by a Dean’s Grant from the University of Rhode Island.

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TABLE OF CONTENTS

ABSTRACT ..................................................................................................................................... i

DEDICATION ............................................................................................................................... iii

ACKNOWLEDGEMENTS ........................................................................................................... iv

LIST OF TABLES ....................................................................................................................... viii

LIST OF FIGURES .........................................................................................................................x

INTRODUCTION ...........................................................................................................................1

Wetlands ................................................................................................................................................... 1

Wetland Definitions .................................................................................................................................. 2

Hydric Soils and Field Indicators of Hydric Soils .................................................................................... 3

Organic Matter Accumulation .............................................................................................................. 5

Fe and Mn Reduction ............................................................................................................................ 5

Field Indicators of Hydric Soils ............................................................................................................ 7

Problematic Hydric Soils .......................................................................................................................... 7

The Red Beds of the Hartford Rift Basin .................................................................................................. 8

The Red-Colored Soils of the Hartford Rift Basin.................................................................................... 9

Problematic Red-Colored Soils and Field Indicators of Hydric Soils .................................................... 11

METHODOLOGY ........................................................................................................................14

Site Selection .......................................................................................................................................... 14

Site Locations of Previous Studies ...................................................................................................... 14

Soil Sampling, Description, and Characterization .................................................................................. 16

Vegetation Sampling ............................................................................................................................... 17

Hydrology Monitoring ............................................................................................................................ 19

Precipitation Monitoring ......................................................................................................................... 21

IRIS Tubes .............................................................................................................................................. 22

Redox Potential ....................................................................................................................................... 24

Growing Season and Soil Temperature .................................................................................................. 25

Growing Season .................................................................................................................................. 25

Soil Temperature ................................................................................................................................. 26

RESULTS ......................................................................................................................................28

vi

CCPI Analysis ......................................................................................................................................... 28

Growing Season ...................................................................................................................................... 28

Precipitation ............................................................................................................................................ 28

Saturation ................................................................................................................................................ 34

Anaerobic Conditions ............................................................................................................................. 38

IRIS Tubes .......................................................................................................................................... 38

Redox Potential ................................................................................................................................... 53

Soil Morphology ..................................................................................................................................... 53

General Characteristics ....................................................................................................................... 53

Redoximorphic Features ..................................................................................................................... 59

Vegetation ............................................................................................................................................... 66

DISCUSSION ................................................................................................................................73

Hydric Soil Technical Standard .............................................................................................................. 73

Veteran’s Field .................................................................................................................................... 73

Cooke Road ......................................................................................................................................... 74

Tyler Mill ............................................................................................................................................ 75

Auerfarm ............................................................................................................................................. 76

Wadsworth Estate ............................................................................................................................... 77

Field Indicators of Hydric Soils and Soil Morphology ........................................................................... 77

Data Issues .............................................................................................................................................. 79

Hydrology Data ................................................................................................................................... 79

Redox Potential ................................................................................................................................... 80

CONCLUSION AND RECOMMENDATIONS ..........................................................................82

LITERATURE CITED ..................................................................................................................85

vii

LIST OF TABLES

TABLE PAGE

Table 1. CCPI results for all wetland monitoring stations .............................................................29

Table 2. Start and end of growing season for all sites ...................................................................30

Table 3. Water table summary for each monitoring station at the Wallingford sites in 2012 and

2013.................................................................................................................................39

Table 4. Water table summary for each monitoring station at the Auerfarm site in 2006, 2007,

and 2008 ..........................................................................................................................40

Table 5. Water table summary for each monitoring station at the Wadsworth Estate site in 2008

and 2009 ..........................................................................................................................41

Table 6. Water table summary for each monitoring station at the Wallingford sites in 2012 and

2013, without regard for precipitation ............................................................................42

Table 7. IRIS tube data for wetland and upland monitoring stations at the Wallingford sites ......54

Table 8. Landscape position and classification of each pedon ......................................................60

Table 9. Soil profile descriptions for the Veteran’s Field site .......................................................61

Table 10. Soil profile description for the Cooke Road site............................................................62

Table 11. Soil profile description for the Tyler Mill site ...............................................................63

Table 12. Soil profile description for the Auerfarm site ................................................................64

Table 13. Soil profile description for the Wadsworth Estate site ..................................................65

Table 14. Dominant vegetation for the Veteran’s Field site ..........................................................68

Table 15. Dominant vegetation for the Cooke Road site ...............................................................69

Table 16. Dominant vegetation for the Tyler Mill site ..................................................................70

Table 17. Dominant vegetation for the Auerfarm site ...................................................................71

viii

Table 18. Dominant vegetation for the Wadsworth Estate site .....................................................72

Table 19. Hydric soil indicators associated with each monitoring station ....................................78

ix

LIST OF FIGURES

FIGURE PAGE

Figure 1. Site location map ............................................................................................................15

Figure 2. Soil temperature data for the Wallingford sites ..............................................................31

Figure 3. Soil temperature data for the Auerfarm site ...................................................................32

Figure 4. Soil temperature data for the Wadsworth Estate site ......................................................33

Figure 5. Local monthly total precipitation data for the Wallingford sites ...................................35

Figure 6. Local monthly total precipitation data for the Auerfarm site .........................................36

Figure 7. Local monthly total precipitation data for the Wadsworth Estate site ...........................37

Figure 8. Hydrograph and piezometer readings for VF1 in 2012 and 2013 ..................................43

Figure 9. Hydrograph and piezometer readings for VF2 in 2012 and 2013 ..................................44

Figure 10. Hydrograph and piezometer readings for CR1 in 2012 and 2013 ................................45

Figure 11. Hydrograph for CR2 in 2012 and 2013 ........................................................................46

Figure 12. Hydrograph and piezometer readings for TM1 in 2012 and 2013 ...............................47

Figure 13. Hydrograph and piezometer readings for TM2 in 2012 and 2013 ...............................48

Figure 14. Hydrograph for AF1 in 2006, 2007, and 2008 .............................................................49

Figure 15. Hydrograph for AF2 in 2006, 2007, and 2008 .............................................................50

Figure 16. Hydrograph for WE1 in 2008 and 2009 .......................................................................51

Figure 17. Hydrograph for WE2 in 2008 and 2009 .......................................................................52

Figure 18. Mean and range of redox potential data at 15 cm for WE1 in 2008 ............................55

Figure 19. Mean and range of redox potential data at 15 cm for WE1 in 2009 ............................56

Figure 20. Mean and range of redox potential data at 30 cm for WE1 in 2008 ............................57

Figure 21. Mean and range of redox potential data at 30 cm for WE1 in 2009 ............................58

x

INTRODUCTION

Wetlands

Wetlands are transitional areas between terrestrial and aquatic ecosystems (Mitsch &

Gosselink, 2007). They provide critically important environmental and socio-economic

functions, including foraging, nesting, and aestivation habitat for organisms; flood attenuation

and sediment/nutrient/toxicant retention, transformation, and removal; groundwater recharge;

and, in some cases, human food production (e.g., rice and cranberries; Mitsch & Gosselink,

2007). However, until the mid-twentieth century, scientists had yet to obtain a robust

understanding of these functions, and, as such, the public generally perceived wetlands as

nothing more than insect-ridden wastelands (Larson & Kusler, 1979). In many cases, wetlands

were the center of land reclamation projects and dumping, or were drained and converted to

agricultural uses. In fact, it is estimated that over 50% of wetlands in the conterminous United

States were lost between 1780 and 1980 (Mitsch & Gosselink, 2007).

In the mid-to-late 1960’s the issue of environmental degradation finally came to the

attention of the American public. Centuries of abuse to the Nation’s natural resources had led to

disturbing events, such as the Cuyahoga River fire, and opened the public’s eyes to the need for

change. Over the course of the next decade, several pieces of landmark legislation were passed

in an effort to provide meaningful protections for the Nation’s natural resources. One such piece

of legislation, passed in 1972, is the Federal Water Pollution Control Act, known widely as the

Clean Water Act (CWA; 33 U.S.C.A. § 1251 et seq.). Using the Commerce Clause of the United

States Constitution as its backbone, the objective of the CWA is to “restore and maintain the

chemical, physical, and biological integrity of the Nation’s waters” (33 U.S.C.A. § 1251(a)).

Section 404 of the CWA, established under the 1977 CWA amendments, prevents the discharge

1

of “dredged or fill material” into “navigable waters” of the Unites States without a permit (Moya

& Fono, 2011). While the CWA broadly defines “navigable waters” as “waters of the United

States, including territorial seas,” regulations promulgated by the United States Army Corps of

Engineers (USACE) and the United States Environmental Protection Agency, the joint

administrators of the Section 404 permit program, have further defined “navigable waters” to

include intrastate waters, intermittent streams, man‐made channels, and wetlands, among others

(Moya & Fono, 2011). It is Section 404 of the CWA that represents the primary mechanism for

wetlands protection at the federal level.1

Wetland Definitions

With the promulgation of the CWA, there became an immediate need to create a

regulatory definition of what a wetland was, and develop a rapid and defensible means to

identify them (Mitsch & Gosselink, 2007). In 1982, the USACE published the currently

accepted definition of wetlands for use with Section 404 of the CWA, which reads:

Those areas that are inundated or saturated by surface or ground water at a frequency

and duration sufficient to support, and that under normal circumstances do support, a

prevalence of vegetation typically adapted for life in saturated soils. Wetlands

generally include swamps, marshes, bogs, and similar areas. (Mausbach & Parker,

2001)

This regulatory definition is based on a scientific definition developed by the United States

Department of the Interior, Fish and Wildlife Service (USFWS) in the mid-to-late 1970’s as part

of the National Wetlands Inventory program (NWI; Mausbach & Parker, 2001). The primary

1 It is acknowledged that there are additional mechanisms for protecting wetlands at the federal level. Section 404 is the most common, and, as such, other laws (e.g. Rivers and Harbors Act; Food Security Act) are not discussed.

2

publication associated with the NWI program, Classification of Wetlands and Deepwater

Habitats of the United States (Cowardin, Carter, Golet & LaRoe, 1979), defines wetlands as

follows:

Wetlands are lands transitional between terrestrial and aquatic systems where the

water table is usually at or near the surface or the land is covered by shallow water.

For the purposes of this classification, wetlands must have one or more of the

following three attributes: (1) at least periodically, the land supports predominantly

hydrophytes; (2) the substrate is predominantly undrained hydric soil; and (3) the

substrate is nonsoil and is saturated with water or covered by shallow water at some

time during the growing season of each year.

The USFWS definition identifies what has become known as the three diagnostic environmental

characteristics (or factors) of wetlands: 1) the presence of hydrophytic vegetation; 2) the

presence of hydric soil; and 3) the presence of wetland hydrology (i.e., a near-surface seasonally

high water table). These three characteristics form the basis for field identification of wetlands

(i.e., wetland delineation; Tiner, 1999). Hydric soils are the focus of this paper.

Hydric Soils and Field Indicators of Hydric Soils

The term hydric soil was first used in Cowardin et al. (1979). No formal definition is

provided, but the document does indicate that a hydric soil is “predominately undrained”

(Mausbach & Parker, 2001). Realizing that a formal definition was needed, the USFWS

solicited the help of the United States Department of Agriculture, Soil Conservation Service

(USDA-NRCS2). In response, the USDA-NRCS formed the National Technical Committee for

2 In 1994, the Soil Conservation Service’s name was changed to the Natural Resources Conservation Service. For simplicity, the acronym USDA-NRCS will be used in reference to both.

3

Hydric Soils (NTCHS). The NTCHS released the first definition and criteria of a hydric soil in

1985. Since that time, it has been revised regularly as scientific understanding expands. The

current definition, published in 1995, reads: “A hydric soil is a soil that formed under conditions

of saturation, flooding, or ponding long enough during the growing season to develop anaerobic

conditions in the upper part” (Mausbach & Parker, 2001). The critical element of the current

definition is the presence of “anaerobic conditions,” which is requisite in the morphological

development of a hydric soil.

The development of anaerobic conditions is understood to be a biologically mediated

process, in which microbes, plants, and animals all play an important role (Craft, 2001). Central

to this process is the metabolic oxidation of organic matter by heterotrophic microorganisms,

particularly bacteria and fungi (Craft, 2001). In an oxygen-rich environment, aerobic

microorganisms synthesize organic matter using oxygen as an electron acceptor (Schwertmann

& Taylor, 1989; Craft, 2001). Organic carbon is converted to carbon dioxide gas in the

subsequent reaction. Under conditions of saturation, flooding, or ponding, however, the vast

majority of soil pores become waterlogged. Oxygen diffuses approximately 10,000 times slower

through water than air, and, as such, will be quickly depleted through microbial respiration

(Ponnamperuma, 1972; Mitsch & Gosselink, 2007). The resulting condition is anaerobiosis (i.e.,

reducing conditions). There are several biogeochemical implications of anaerobiosis within the

soil. These revolve around the oxidation-reduction reactions that occur under such conditions

and are significant in the formation of morphological features in the soil. The two principal

processes are: 1) organic matter accumulation, and 2) Fe and Mn reduction (Vepraskas, 2001).

4

Organic Matter Accumulation

When the soil environment becomes anaerobic, aerobic microorganisms die off or

become dormant, and facultative soil microbes become the dominant organism in the synthesis

of organic matter (Craft, 2001). With oxygen virtually absent from the soil, these microbes must

look to other electron acceptors in order to complete the requisite reaction. There are several

oxidized ions that serve this role, including NO3-, Mn4+, Fe3+, and SO4

2- (Ponnamperuma,

1972). The associated reactions are much less energetic compared to those under aerobic

conditions, and result in slower decomposition rates (Ponnamperuma, 1972; Mitsch & Gosselink,

2007). In addition, soils may contain fewer active microorganisms under anaerobic conditions,

which can also limit decomposition rates (Lee, 1992). Both of the aforementioned processes

ultimately result in organic matter accumulation. The principal source of organic matter is from

primary production (e.g., plants). Therefore, accumulation occurs at or near the soil surface,

resulting in surficial deposits of partially decomposed organic matter (e.g., histic epipedons and

Histosols), mucky mineral soil material, dark-colored mineral surface horizons, and organic

bodies (Vepraskas, 2001). In some cases, organic acids can leach into the subsoil, as observed in

Spodosols (Mokma, 1993).

Fe and Mn Reduction

Fe oxides represent the most abundant metallic oxide minerals we see in soil

(Schwertmann & Taylor, 1989). As one would expect, Fe also has the most significant impact

on soil color, particularly in the subsoil and substratum, where organic matter exerts less

influence. In aerobic environments, Fe oxides often coat the surfaces of the soil mineral

particles, resulting in matrices that display varying degrees of yellow, orange, red, and brown

(Schwertmann, 1993; Vepraskas, 1999). Mn, while much less abundant, also has a coloring

5

effect (Vepraskas, 2001). As noted previously, Fe3+, and to a lesser extent, Mn4+ are two

oxidized ions that commonly serve as an alternative electron acceptor under anaerobic conditions

(Vepraskas, 1999; Vepraskas, 2001; Mitsch & Gosselink, 2007). Both Fe and Mn are soluble in

their reduced form, and may enter the soil solution and be translocated or completely leached

from the soil profile (Schwertmann & Taylor, 1989; Vepraskas, 1999). This will leave the

uncoated mineral grains as the primary coloring agent. These grains are generally composed of

quartz and other minerals with low chroma colors that collectively appear gray. In some cases,

bluish-green (i.e., gleyed) colors are observed, which may indicate the presence of reduced Fe

attached to an anion of another compound, such as SO42- (Tiner, 1999; Vepraskas, 2001). It

should be noted that the soil environment is never entirely devoid of oxygen (Ponnamperuma,

1972). In many cases oxygen can be found in the interstices of the matrix, along roots and

within pores. In addition, there is temporal variation in groundwater associated with all

wetlands, which may result in alternating wet and dry periods (Mitsch & Gosselink, 2007).

Wherever oxygen is present in the soil, any reduced Fe or Mn in solution will oxidize and

precipitate.

The reduction and oxidation reactions described above ultimately result in a

heterogeneous distribution of colors, including yellow, orange, red, brown, gray, and black.

These color patterns are commonly referred to as redoximorphic features (Vepraskas, 1999).

They include reduced/depleted matricies, depletions, and concentrations (Vepraskas, 1999).

Concentrations are further divided into Fe masses, pore linings, concretions, and nodules

(Vepraskas, 1999).

6

Field Indicators of Hydric Soils

The morphological features described in the preceding sections are common to most

hydric soils, and are expressed to varying degrees depending on site-specific conditions. These

morphologies, at specified depths from the soil surface (and some non-morphological features

not discussed here) are referred to as “field indicators of hydric soils,” and are used by soil and

wetland scientists to identify hydric soils in the field. The indicators are described in Field

Indicators of Hydric Soils in the United States: A Guide for Identifying and Delineating Hydric

Soils (FIHSUS; USDA-NRCS, 2010), which is developed and maintained by the NTCHS. The

indicators are applied regionally through the applicable regional supplement to the 1987 Corps of

Engineers’ Wetlands Delineation Manual (USACE, 2012).

Problematic Hydric Soils

Despite almost 30 years of use and development of these indicators nation-wide, there are

several “problematic soils” recognized by the NTCHS that possess near-surface seasonally high

water tables, but do not conform to the current hydric soil morphological paradigm (Vepraskas &

Sprecher, 1997). This “anomalous soil hydromorphology” is often caused by chemical

conditions that prevent reduction (Rabenhorst & Parikh, 2000). This can include low organic

carbon content and low soil temperature, which limits microbial activity; higher oxygen content,

which can prevent the soil environment from achieving anaerobiosis (and thus, reducing

conditions); lack of Fe and Mn coatings, which reduces the availability of alternative electron

acceptors; and high alkalinity, which can preclude the dissolution and translocation of oxidized

Fe and Mn (Tiner, 1999). Problematic soils may also result from properties of the soil itself

(Rabenhorst & Parikh, 2000). For example, uncoated grains within the soil may have a high

chroma, which can prevent the expression of those colors typically found in soils under reducing

7

conditions (Rabenhorst & Parikh, 2000). In dunal soils, Fe or Mn may be completely absent,

which precludes development of redoximorphic features (Vepraskas & Sprecher, 1997). The

mineralogy of the coatings on grains can also be important. In many cases, dominant iron oxide

minerals are highly stable (e.g., hematite and goethite) and have extremely high solubility

products, which can increase resistance to reduction (Torrent & Schwertmann, 1987; Rabenhorst

& Parikh, 2000).

The Red Beds of the Hartford Rift Basin

The Hartford Rift Basin3 is a ±140 km long half graben that runs through central

Connecticut and the Connecticut River Valley of Massachusetts from Long Island Sound near

New Haven, northward, to the Massachusetts-Vermont border, and contained within Major Land

Resource Area (MLRA) 145 (Connecticut Valley) of Land Resource Region (LRR) R (USDA-

NRCS, 2006). It is part of a chain of basins located along the eastern seaboard of North

America, extending from Florida to Newfoundland (Hubert, Reed, Dowdall, & Gilchrist, 1978).

These basins were created as a result of tensional forces associated with the rifting of the

Pangaea supercontinent during the Late Triassic Period, approximately 200 million years ago

(Hubert et al., 1978; Elless & Rabenhorst, 1994). Subsequent infilling by alluvium during the

Late Triassic and Early Jurassic resulted in the accumulation of several kilometers of sediment

(Elless & Rabenhorst, 1994; Merguerian & Sanders, 2010). This sedimentary fill lithified,

forming an assemblage of lithologies, including breccia, conglomerate, sandstone, mudstone,

siltstone, and shale that are collectively referred to as the Newark Supergroup (Hubert et al.,

1978).

3 For simplification, it is implied that the Hartford Rift Basin includes the Pomperaug and Cherry Valley outliers, which are geologically similar, but geographically distinct, located immediately west of the basin.

8

The most striking morphological characteristic of the basin formations are their reddish

color, which have led many to refer to them as red beds. This pigmentation is derived from iron

oxide minerals (Van Houten, 1973; Hubert et al., 1978; Elless & Rabenhorst, 1994; Mokma &

Sprecher, 1994). Several studies have been conducted on the mineralogy of redbeds. These

studies have revealed that the formations are monomineralic, composed almost exclusively of

hematite (Van Houten, 1973; Torrent & Schwertmann, 1987; Blodgett, Crabaugh, & McBride,

1993; Elless & Rabenhorst, 1994).

The formation of hematite in red beds is a process that is not clearly understood. Since

the 1960’s, the prevailing opinion has been that post-depositional diagenetic processes are the

primary contributor (Blodgett et al., 1993). Hubert et al. (1978), identified two principal

diagenetic processes that appear important to the formation of hematite in the red beds of the

Hartford Rift Basin, both of which are attributable to the paleoclimate of the Late Triassic

Period. During this time, the location of the basin was approximately 15 degrees north

paleolatitude; an area that is believed to have been semi-arid and hot (Hubert et al., 1978).

Under these conditions, a collection of iron oxides (formerly referred to as limonite), can often

be found on the surfaces of sand and mud particles (Van Houten, 1973). It is postulated that,

over time, these oxides converted to hematite through hydrolysis. Another possibility is that Fe-

silicate grains (e.g., pyroxene) dissolved and re-precipitated as ferric oxide that converted to

hematite over time (Hubert et al., 1978). Other processes, including the oxidization of magnetite

grains, appear to play a secondary role (Van Houten, 1973; Hubert et al., 1978).

The Red-Colored Soils of the Hartford Rift Basin

MLRA 145 is dominated by soils derived from red-colored parent materials. This area,

as with the entirety of New England, was covered by the Laurentide Ice Sheet during the

9

Wisconsinan glaciation (USDA-NRCS, 2006). As such, red-colored soils are found within all

glacially derived deposits, including glacial till (Holyoke, Yalesville, Cheshire, Watchaug,

Wethersfield, Ludlow, Wilbraham, and Menlo series), glaciofluvial (Manchester, Penwood, and

Hartford series), and glaciolacustrine (Berlin series). They can also be found within deposits of

post-glacial alluvium (Bash series). Soil drainage class ranges from excessively drained to very

poorly drained (Connecticut Department of Environmental Protection & USDA-NRCS, 2006).

Like most soils derived from monomineralic red beds of Triassic and Jurassic origin, soils within

MLRA 145 have typical Munsell hues ranging from 7.5YR to 10R, owing to the nature of the

parent material.

Soils derived from red-colored parent materials have been observed to be highly resistant

to the color transformations typically observed under reducing conditions (Mokma and Sprecher,

1994; Elless, Rabenhorst, & James, 1996). This is due to the hematitic mineralogy of the soil.

Many soils derived from these materials and exhibiting near-surface seasonally high water tables

typically have matricies with a Munsell value and chroma of 3 or more, and redoximorphic

features are often poorly expressed (Elless et al., 1996). Elless et al. (1996) cited Fey (1983),

who postulated that higher levels of isomorphous substitution of Al for some of the Fe in the

hematite mineral results in a resistance to pedogenic yellowing of the profile, which could

partially explain the persistence of high-chroma colors under reducing conditions. In the

Hartford Rift Basin, this anomalous soil hydromorphology is most often observed along the

poorly drained margins of discharge wetlands. These wetlands occur along the concave

footslope and backslope position on drumlins and other landscape features associated with

lodgement till, where a high degree of lateral groundwater flow is present. The Wilbraham

series (coarse-loamy, mixed, active, nonacid, mesic Aeric Endoaquept) is associated with these

conditions. This series is limited to MLRA 145. The State of Connecticut contains the largest

10

distribution of the series, which, along with the Wilbraham–Menlo undifferentiated group,

represents approximately 4.6% (21,000 acres) of the nearly 452,000 acres of hydric soils mapped

in the state (Metzler & Tiner, 1992).

Problematic Red-Colored Soils and Field Indicators of Hydric Soils

The problematic red-colored hydric soils of MLRA 145 have long been an issue for

wetland and soil scientists, and there is a critical need to develop a rapid means of field

identification. MLRA 145 is a highly urbanized area, with large cities such as New Haven and

Hartford, Connecticut and Springfield, Massachusetts, located within its reach. As population

growth continues and the footprints of these cities (and others) continue to expand, it becomes

increasingly important to ensure that appropriate interpretation and land use decisions are being

made.

Over the last two decades, several attempts have been made to develop an effective

hydric soil indicator for these areas. In the mid-1990’s the test indicator TF2 was developed for

all LRR’s containing red parent materials. The indicator reads:

In parent material with hue of 7.5YR or redder, a layer at least 10 cm (4 inches) thick

with a matrix value and chroma of 4 or less and 2 percent or more redox depletions

and/or redox concentrations occurring as soft masses and/or pore linings. The layer is

entirely within 30cm (12 inches) of the soil surface. The minimum thickness

requirement is 5 cm (2 inches) if the layer is the mineral surface layer. (USDA-NRCS,

2010)

This indicator proved very effective in New England, but was observed to be too inclusive in

other parts of the United States with these soils (e.g., the Mid-Atlantic region; D. Parizek,

11

personal communication, April 7, 2012). In response, the Mid-Atlantic Hydric Soil Technical

Committee developed indicator F21, which was approved for use in MLRAs 147 and 148 of

LRR S and MLRA 127 of LRR N, and for testing in all other areas of red parent material

(USDA-NRCS, 2013). The F21 indicator is described in the 2013 errata to FIHSUS:

A layer derived from red parent materials (see glossary) that is at least 10 cm (4

inches) thick, starting within 25 cm (10 inches) of the soil surface with a 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 percent or more depletions and/or distinct or prominent

redox concentrations occurring as soft masses or pore linings. Redox depletions

should differ in color by having:

a. Value one or more higher and chroma one or more lower than the matrix, or

b. Value of 4 or more and chroma of 2 or less. (USDA-NRCS, 2013)

Anecdotal observations from wetland and soil scientists in New England and empirical data

derived from two sites in MLRA 145 suggested that the indicator was too restrictive for use

within the region. Specifically, abundance requirements for redoximorphic features were

substantially greater than what was observed in MLRA 145 (D. Parizek, personal

communication, April 7, 2012). In addition, the indicator excluded soils with faint contrast,

which, in MLRA 145, eliminated several soils that fell within areas clearly functioning as

wetlands. The reasons for the ineffectiveness of F21 in New England are not entirely

understood. It is postulated that the age of the soils in the basin and differences in soil

temperature may be a factor (D. Parizek, personal communication, April 7, 2012). As the Mid-

Atlantic was not glaciated and has a warmer climate, pedogenesis is far more advanced than in

12

New England, which could explain the clearer expression and greater abundance of

redoximorphic features. No research has been conducted to test either hypothesis, however.

With the data pointing against the use of F21 in New England, the New England Hydric

Soil Technical Committee petitioned the NTCHS to move TF2 to full indicator status. However,

despite these efforts, TF2 was retracted from FIHSUS upon the acceptance of F21, with LRR R

included in those regions approved for testing (USDA-NRCS, 2013). In 2014, the NTCHS

confirmed the reach of F21 to include MLRA 145 in order to temporarily deal with the absence

of an approved indicator in New England (L. Vasilas, personal communication, May 28, 2014).

In this study, we built off of the previous, unpublished work completed by the USDA-

NRCS and the University of Massachusetts, Amherst at two sites in MLRA 145 by expanding

the study sample size to include three additional sites in the Town of Wallingford, New Haven

County, Connecticut. A multi-parameter, paired site approach was implemented, which included

detailed soil profile descriptions, vegetation sampling, hydrologic data collection, and

documentation of reducing conditions. This approach intended to follow the requirements of the

“National Hydric Soil Technical Standard” (HSTS; NTCHS, 2007) which is designed to identify

the presence of both 1) anaerobic conditions, and 2) saturated conditions within the upper part of

the soil, and would confirm the presence of hydric soil under the current USDA-NRCS

definition. These data were combined with the existing data collected at the two original sites

with the goals of: 1) testing the utility of indicator F21 and the former indicator TF2 in the New

England region; and 2) making recommendations to the NEHSTC regarding future development

of a hydric soil indicator for soils derived from red-colored glacial till in New England.

13

METHODOLOGY

Site Selection

Three study sites were established within Wallingford, New Haven County, Connecticut,

which falls within MLRA 145 (Connecticut Valley) of LRR R (USDA-NRCS, 2006; Figure 1).

Sites were selected based on the following criteria: 1) soils are problematic (i.e., contain the

Wilbraham series); 2) a wetland boundary is contained within the site; 3) sites are easily

accessible; and 4) sites are located on publicly-owned lands. A GIS-based analysis was

completed to identify several parcels that met criteria 1, 3 and 4. Preliminary field investigations

were conducted to confirm the presence of problematic soils as well as criterion 2. The three

study sites were monitored between March 2012 and September 2013 and are referred to as

Veteran’s Park (VF), Cooke Road (CR), and Tyler Mill (TM; collectively, Wallingford sites).

At each study site, two monitoring stations were established. One station was sited in

what was perceived to be a poorly drained (i.e., wetland) landscape position, while the other was

located in a moderately well-drained or well-drained (i.e., upland) landscape position.4 Both

stations were sited near the wetland-upland boundary to achieve a comparison of

hydromorphological characteristics. Monitoring stations were located in areas that had limited

anthropogenic disturbance, and were unlikely to be subjected to vandalism.

Site Locations of Previous Studies

Sites associated with the previous studies are located at the 4-H Education Center at

Auerfarm (AF) in Bloomfield, Hartford County, Connecticut and the Wadsworth Estate (WE) in

4 References to specific monitoring stations will consist of the site initials and a numerical suffix to denote a wetland (1) or upland (2) station (e.g., Cooke Road Wetland = CR1).

14

15

Middletown, Middlesex County, Connecticut, both of which are also located in MLRA 145

(USDA-NRCS, 2006; Figure 1). The Auerfarm site was evaluated between April 2006 and June

2008 by staff from the USDA-NRCS 12-TOL soil survey office. The Wadsworth Estate site was

evaluated between April 2008 and July 2009 by researchers at the University of Massachusetts,

Amherst. It should be noted that these sites originally used a transect-based approach, with

several observation points along a hydrotoposequence. In order to maintain consistency with the

paired site approach used in the current study, only those data collected from the two points

immediately above and below the perceived wetland boundary were used.

Soil Sampling, Description, and Characterization

Soils were described and sampled at all three Wallingford sites and WE1 between July

24, 2012 and August 9, 2012. WE2 and the Auerfarm site were described in the spring of 2007

and 2006, respectively. All soil pits were dug by hand using a spade to depths ranging from 80

to 200 cm. An auger was used if the presence of water or depth of the pit limited the utility of a

spade. Soils were described using the methodology established by the National Cooperative Soil

Survey, and found within Schoeneberger et al. (2012). Soils were classified using Keys to Soil

Taxonomy (12th Edition; Soil Survey Staff, 2014).

Bulk and undisturbed samples of each horizon were collected for all wetland pedons,

except AF1. The bulk samples were sealed in polyethelene bags and used for general

characterization. Undisturbed samples (for measurement of bulk density) were placed in a

hairnet, dipped in paraffin, and stored in boxes for transport. The samples were sent to the

National Soil Survey Laboratory in Lincoln, Nebraska for a complete physical and chemical

characterization.

16

The characterization analysis also included a metric of the Color Change Propensity

Index (CCPI; Rabenhorst & Parikh, 2000). This analysis was developed specifically for use in

soils derived from red colored parent materials and is used to ensure that the sediments overlying

red-colored bedrock are derived from said bedrock. Soils having CCPI values of 30 or less resist

color changes (i.e., have difficulty forming redoximorphic features) and are considered

problematic (Rabenhorst & Parikh, 2000). The Bw1 horizons from VF1 and CR1 were

analyzed.5 A CCPI analysis for the previous study at AF1 and WE1 was completed in 2008 by

the Pedology Research Laboratory at the University of Maryland, College Park. The Bw

horizons from these monitoring stations were analyzed.

Vegetation Sampling

Vegetation sampling at the three Wallingford sites was conducted in July 2014, in order

to characterize the vegetative community during a period of peak biomass. Data for the

Wadsworth Estate and Auerfarm sites were collected in July 2008 and May 2006, respectively.

Sampling methodology followed that prescribed in Environmental Laboratory (1987) and

USACE (2012). The structure of the vegetative community was divided into four strata based

on life form: 1) Herbaceous: all non-woody plants and woody plants ≤1 m in height; 2)

Sapling/Shrub: woody plants less than 7.6 cm in diameter at breast height (DBH) and ≥ 1 m; 3)

Canopy: woody plants greater than 7.6 cm; and 4) Woody Vines: all woody vines greater than 1

m in height. A nested plot arrangement was implemented, which uses single plots in graduated

sizes based on the life form of specific strata. Standard sampling areas were used: 1)

Herbaceous: 1.5 m radius; 2) Sapling/Shrub: 4.6 m radius; and 3) Canopy and Woody Vines: 9.2

m radius. The plot was sited within an area of uniform hydrologic conditions. All species within

5 TM1 was not sampled as the close geographical proximity of the Wallingford sites did not warrant separate analysis.

17

each stratum were assigned a value of absolute percent cover. Plants which could not be

identified to species in the field were collected and identified at a later date. Any species that

exhibited a morphological adaptation on 50% or more of observed individuals was noted.

To determine if the plot area associated with each monitoring station supported a

hydrophytic plant community, the following three hydrophytic vegetation indicators6 were used:

1) dominance test; 2) prevalence index; and 3) morphological adaptations (USACE, 2012). The

dominance test indicator uses the “50/20 rule” to evaluate each strata. The total absolute cover

for each stratum was calculated. This value was multiplied by .50 and .20. Those species which

had the highest absolute cover percentages and individually or collectively have relative cover

percentages greater than 50% were considered dominant. In addition, those species which

individually had a relative cover percentage greater than 20 were also considered dominant.

Those strata with less than 5% cumulative cover were omitted, unless they were the only stratum

present. The number of dominant species with an indicator status of FAC (i.e., occurs in

wetlands and uplands equally) or wetter was then divided by the total number of dominant

species. If more than 50% of the dominant plant species across all strata have an indicator status

of FAC or wetter, the plant community would be considered hydrophytic. If a particular plot

failed to meet the dominance test, the prevalence index indicator was implemented, which uses a

weighted average based on indicator status to determine the dominance of a particular wetland

community. The absolute cover of each species was multiplied by a specific value based on its

indicator status (OBL = 1, FACW = 2, FAC = 3, FACU = 4, and UPL = 5). The summation of

each species was then divided by the sum of the absolute cover for each species. An index value

of 3.0 or less would indicate the presence of a hydrophytic plant community. If a plot failed the

prevalence index, the morphological adaptations indicator was implemented. Any species that

6 The rapid test was not used.

18

exhibited a morphological adaptation on 50% or more individuals and had an associated

indicator status of FACU were reassigned an indicator status of FAC. The dominance test and, if

needed, prevalence index were then re-calculated. If the plot failed the recalculated tests, the

plant community was considered non-hydrophytic.

Hydrology Monitoring

At the Wallingford sites, one water table well and one shallow piezometer were installed

at each monitoring station, with the exception of CR2, where only a water table well was

installed.7 Wells and piezometers were constructed following the standards prescribed in

USDA-NRCS (2008). A bucket auger was used to excavate the hole required to install the well;

however, in some cases, stoniness required the use of a spade. Water table wells were

constructed out of 5 cm diameter8 schedule 40 polyvinyl chloride (PVC) pipe, and screened with

slotted sections of pipe (0.05 cm slots with 0.5 to 2.54 cm spacing). Once installed, the entire

reach of the well screen was backfilled with sand. The remaining depth was backfilled with a

native soil-bentonite mixture (C/S Granular 30-50 mesh; CETCO International, Hoffman Estates,

IL). Risers were installed at least 15 cm above grade and capped to ensure that surface water

and/or precipitation would not enter the wells.

An Odyssey capacitance water level recorder (Dataflow Systems Pty. Ltd., Christchurch,

NZ) was installed within each water table well. Each device was calibrated by the USDA-

NRCS, using an unpublished procedure described in USDA-NRCS (n.d.).9 Measurements were

programmed to be taken at 4 hour intervals. Water level recorders were removed and their data

7 Due to the landscape position associated with CR2, it was not anticipated that water levels would rise within 25 cm of the soil surface. 8 The 5 cm diameter PVC was selected due to the diameter of the monitoring equipment being used. 9 The calibration methods used for this study have been observed to result in measurement error. Please see the Discussion for further details.

19

uploaded onto a PC at approximately 6 month intervals. There were not enough water level

recorders for each well at the start of the experiment. As such, one monitoring station (TM2)

was measured manually for the entire monitoring period, and two monitoring stations (VF1, and

VF2) were measured manually between March 2012 and August 2012. Manual measurements

were taken at weekly intervals, using a flashlight and tape-measure. All monitoring wells were

measured by hand when on site to confirm the accuracy of measurements taken by the water

level recorders and ensure that no vertical movement in the wells had occurred.

Piezometers were constructed out of 5 cm diameter schedule 40 PVC. In most cases, a

PVC cap with a single hole was affixed to the bottom of the piezometer; however, lack of

materials required an alternative design where holes were drilled near the base of the pipe, and

the entire base was wrapped in filter fabric. Piezometers were installed above densic contact,

generally between 30 and 38 cm. As with the water table wells, the screen or base of the well

was backfilled with sand and the remainder of the tube backfilled with a native soil-bentonite

mixture. Piezometers were measured manually at weekly intervals.

At the Wadsworth Estate site, one water table well was installed at each monitoring

station and measurements were conducted between April 2008 and June 2009. At the Auerfarm

site, water table wells were installed and monitored between April 2006 and June 2008. Water

table wells were constructed similarly to those methods described above. Wells were measured

manually at both sites. At the Auerfarm site, measurements were made at least once per month,

with the exception of September 2007 and February 2008. At the Wadsworth Estate site, water

table wells were also measured at least once per month, with the exception of August 2008,

January 2009, and February 2009.

20

Precipitation Monitoring

Precipitation data for the three Wallingford sites and the Wadsworth Estate site were

collected from Meriden-Markham Municipal Airport in Meriden, Connecticut (approximately

8.9 to 13 km from sites). Data for the Auerfarm site were collected from Hartford-Brainard

Airport in Hartford, Connecticut (approximately 13 km from site). To determine the departure

from normal conditions (i.e., values between the 30th and 70th percentiles), values for the 30 year

average monthly total precipitation and associated 30th and 70th percentiles were obtained from

the nearest WETS station. The Middletown 4 W (CT4767) WETS station was used for the three

Wallingford sites and the Wadsworth Estate site (approximately 3.8 to 16.1 km from sites). The

West Hartford (CT9162) WETS station was used for the Auerfarm site (approximately 7 km

from site).

Antecedent precipitation conditions were determined using the “Direct Antecedent

Rainfall Evaluation Method” (Sprecher & Warne, 2000). Each of the three months preceding the

month of interest were evaluated. Monthly precipitation totals were related to a particular

precipitation condition, based on their relationship to the range of normal conditions derived

from the WETS tables: 1) drier than normal (i.e., <30th percentile), 2) normal (i.e., between the

30th and 70th percentile), and 3) wetter than normal (i.e., >70th percentile). Each condition was

weighted based on the how much influence a particular month’s precipitation would have on site

hydrology: 1st month prior = multiply by 3, 2nd month prior = multiply by 2, and 3rd month prior

= multiply by 1. The three resulting values were summed, and the following scale was used to

determine the antecedent rainfall condition: 6-9 = drier than normal, 10-14 = normal, 15-18 =

wetter than normal. Per NTCHS (2007), those data collected during periods where monthly total

precipitation was considered wetter than normal were omitted from the HSTS determination.

21

IRIS Tubes

IRIS tubes were installed at the three Wallingford sites to determine the presence of

reducing conditions. These tubes are coated with a synthetic iron oxide paint, which, when

placed in the soil, will be removed if reduction of Fe is actively occurring (Jenkinson &

Franzmeier, 2006). Tubes were constructed using a modified version of an unpublished

procedure developed at the University of Maryland, and derived from Rabenhorst and Burch

(2006). We used 1.9 cm diameter schedule 40 PVC that was cut to 60 cm lengths, cleaned with

acetone, and lightly sanded with very fine (i.e., 220 grit) sandpaper. The synthetic iron oxide

paint was created by dissolving 16 g of anhydrous FeCl3 in 0.5 L of de-ionized (DI) water. The

solution was titrated with 1M KOH (approximately 370 ml) until a pH of 12 was reached and the

resulting suspension was centrifuged at approximately 1000 rpm for 5 minutes. The supernatant

was discarded and the resulting Fe oxide slurry was centrifuge washed twice with DI water,

discarding the supernatant each time. The slurry was transferred to dialysis tubing and placed in

a bath of DI water to remove salts. A slow, steady stream of DI water was started at the base of

the bath to displace the existing water. After three days, the paint was placed in a 500 ml high-

density polyethylene bottle and stored in the dark at room temperature for 3-4 days to allow for

mineralogical alteration. The paint was centrifuged again at 1000 rpm and half the supernatant

discarded, at which point the paint was ready for application to the tubes.

To paint the tubes, a makeshift lathe was created using an electric drill and ring stand. A

number 3 rubber stopper was attached to the chuck jaw of the drill. The diameter of a number 3

stopper is slightly smaller than the inside diameter of a 1.9 cm tube, which allowed the tube to be

connected to the stopper using a friction fit. At the other end, a small diameter piece of PVC was

attached to a ring stand, at a near horizontal orientation. The bottom end of the tube was slid on

22

to the small diameter piece of PVC, providing support to that end of the tube while being rotated

by the drill. A stainless steel adjustable pipe clamp was installed around the drill trigger to free

both hands for painting. The paint was applied to the tube using a 5 cm foam brush, with the

tube rotating away from the individual applying the paint. The lower 55 cm received paint, while

the remaining 5 cm was left unpainted.

Five replicate tubes were installed at each monitoring station, in a uniform area of

approximately 1 m2. As these sites are associated with lodgement till, a 2.2 cm diameter soil

probe was used to find a location where a tube could be easily inserted. A piece of PVC pipe

was then driven into the soil to create a pilot hole. This allowed for the tube to be inserted easily,

while preventing paint abrasion and providing good soil-paint contact. Tubes were inserted to a

depth of 50 cm or refusal and the soil surface was marked on the tube with a permanent marker.

IRIS tube monitoring was replicated twice at all wetland monitoring stations: April 2,

2012 to May 18, 2012 and May 2, 2013 to June 19, 2013. Upland monitoring stations were

monitored once, between October 18, 2013 and November 8, 2013.

Paint removal from the IRIS tubes was quantified using the “mylar-grid” method

(Rabenhorst, 2012). This method was selected as it is reported as more accurate than visual

estimates and does not require customized electronic equipment (i.e., a scanning device;

Rabenhorst, 2012). The HSTS requires that IRIS tubes exhibit 30% or more paint removal

within a 15 cm zone of the upper 30 cm. As such, a grid was designed in AutoCAD (Autodesk,

Inc., San Rafael, CA) measuring 15 cm in length by 8.4 cm in width (i.e., the length which

would cover one circumference of the IRIS tube), with 30 rows and 16 columns (0.5 by 0.525 cm

grid squares). The grid was printed to scale on a standard, letter-size sheet of paper and

transferred to a mylar transparency using a copier. The grid was placed over the perceived

23

location of highest paint removal and held in place with rubber bands or tape. Each grid square

exhibiting 50% or more paint removal was marked with a dot. The number of grid squares with

dots was divided by the total number of grid squares and multiplied by 100, resulting in the

percent proportion of total paint removal.

Redox Potential

Redox potential (Eh) was measured at the Wadsworth Estate site by the University of

Massachusetts, Amherst, between April 2008 and June 2009. Redox probes were installed

within a uniform area at 15 and 30 cm depths. All probes were installed within 10 cm of a salt

bridge, with openings at the same depths as the redox probes. The platinum tipped electrodes

were constructed using the methodology described in Vepraskas and Bouma (1976). 1.25 cm of

platinum wire (20 gauge) was soldered to 12 gauge copper wire. The copper wire was sealed

inside a 0.67 cm PVC pipe using epoxy to prevent water from entering the pipe and seal the

platinum/copper junction. Salt bridges were made from 1.25 cm PVC pipe, filled with saturated

KCl in 3% agar (Veneman & Pickering, 1983). Holes were drilled in the salt bridges to

correspond to the 15 and 30 cm depths of the probes. All redox probes and the salt bridge were

sealed with bentonite once installed.

Field voltage readings were taken at least once per month between April 2008 and June

2009, with the exception of the period between January 2009 and February 2009, which was

assumed to be outside of the growing season. Early in the growing season, before leaf out (i.e.,

April and May), readings were taken once per week. Readings were taken using a calomel (Hg-

HgCl2) reference electrode (Fisher Scientific, Atlanta, GA) attached to a Radio Shack Model 22-

166B digital multimeter (Radio Shack, Fort Worth, TX) and allowed to stabilize before

24

recording.10 Field voltage readings were corrected to the standard hydrogen electrode at pH 7

according to Vepraskas and Faulkner (2001) and the arithmetic mean of the five redox probes

was calculated.

To determine the presence of reducing conditions, corrected mean voltage readings were

compared to a Eh/pH phase diagram depicting the redox potential at which Fe(OH)3 reduces to

Fe2+ (i.e., Fe stability line; NTCHS, 2007). Equation 1, derived from NTCHS (2007), was used

to determine the appropriate voltage:

Equation 1: Eh = 595 – 60(pH)

Growing Season and Soil Temperature

Growing Season

The growing season is defined by the NTCHS as those periods where soil microbes are

active, and not by soil temperature or other biological indicators (NTCHS, 2007). This

definition is based on a growing body of evidence that suggests microbial activity may exist

under more extreme conditions than traditionally understood (e.g., Gelisols). Under the NTCHS

definition, the growing season can be defined using Eh data or IRIS tubes. However, for this

study, Eh data were only collected at one site (Wadsworth Estate), and the IRIS tube data were

not collected at a high enough resolution to make a determination of the growing season at the

Wallingford sites. To combat this issue, soil temperature was used, as it has been observed to be,

generally, a more conservative indicator of microbial activity than standard methods of

measuring reducing conditions (L. Vasilas, personal communication, October 14, 2014). As the

10 It should be noted that prior to late 2009, allowing stabilization of readings during use of a multimeter with low input resistance was common practice. However, Rabenhorst (2009) has observed that this method may yield erroneous results. See the Discussion for more information.

25

Wadsworth Estate site has incomplete soil temperature data (see below), redox potential was

used to determine the growing season, with soil temperature used to corroborate the results.

Soil Temperature

It was assumed that since the three Wallingford sites were located within close

geographical proximity of one another (maximum distance of 3.3 km), soil temperature could be

monitored at only one monitoring station (CR1). Automated HOBO Pendent Temperature

Loggers (Onset Computer Corporation, Bourne, MA) were installed at 30 and 50 cm depths at

the wetland monitoring station. Loggers were removed and the data downloaded to a PC at

approximately 6 month intervals.

Soil temperature at the Auerfarm site was monitored manually using a soil thermometer

between March 2006 and October 2007. Temperatures were taken at least once per month, with

the exception of September 2007, and at a depth of 50 cm. The remainder of the monitoring

period (i.e., between October 2007 and June 2008) was measured using an automated HOBO

Pendent Temperature Logger at both 30 and 50 cm depths. It should be noted that, in

determining the start of the growing season for the Auerfarm site in 2006 and 2007, it was

assumed that when temperatures at 50 cm reach 5° C, temperatures at the 30 cm depth would be

above 5° C as well, since upper portions of the soil profile typically warm more quickly as

ambient temperatures increase. The end of the growing season was assumed by taking a

conservative estimate.

Soil temperatures at the Wadsworth Estate site were manually measured at 30 and 50 cm

for the entire monitoring period. At the 50 cm depth, measurements were made at least once per

month, excepting August 2008, January 2009, and February 2009. At the 30 cm depth,

measurements were taken at least once per month during the height of the growing season. It

26

should be noted, however, that a large period exists between August 2008 and April 2009 where

limited data was collected (December 17, 2008 and March 16, 2009 only). The reasons for this

are unknown.

27

RESULTS

CCPI Analysis

CCPI values ranged from 14.43 (VF1) to 21.71 (AF1; Table 1). All four monitoring

stations analyzed fell within the “problematic” range (i.e., below 30).

Growing Season

For the purposes of this paper, the growing season is defined by 1) soil temperatures at or

above 5˚ C within 30 cm of the soil surface for the Wallingford sites and Auerfarm; and 2) Eh

measurements below 277 mV at 30 cm for the Wadsworth Estate site (corroborated by soil

temperature). Soil temperature data from CR1 revealed that the growing season at the

Wallingford sites in 2012 extended from the initiation of data collection (April 2nd) to November

29th (Table 2; Figure 2). In 2013, the growing season extended from April 5th through the

remainder of the monitoring period (August 30th).

At the Auerfarm site, the growing season extended from April 24th to December 13th in

2006 (Table 2; Figure 3). In 2007, the growing season extended from April 24th to December

15th. In 2008, the growing season extended from April 5th to the end of the monitoring period

(July 11th).

At the Wadsworth Estate site, the growing season extended from April 25th to December

17th in 2008 (Table 2; Figures 4, 20, and 21). In 2009, the growing season extended from April

7th to the end of the monitoring period (June 12th).

Precipitation

Of the 18 months the Wallingford sites were monitored, 10 months had precipitation

totals below the 30th percentile, and 2 months (June and July 2013) were well above the 70th

28

29

Table 1. CCPI Results for all wetland monitoring stations. Samples with a CCPI value below 30 are considered problematic. Data courtesy of the USDA-NRCS and the University of Maryland, College Park.

Station Horizon CCPI Value Status

VF1 Bw1 14.43 Problematic

CR1 Bw1 16.90 Problematic

TM1 nd nd nd

AF1 Bw 21.71 Problematic

WE1 Bw 18.37 Problematic nd = not determined.

30

Table 2. Start and end of growing season for all sites. Growing season was determined by soil temperatures above 5˚ C at 30 cm, with the exception of the Wadsworth Estate site, which was determined by a redox potential below 277 mV at 30 cm, and corroborated by soil temperatures above 5˚ C at 30 cm.

Wallingford

Year

2012 2013

April 2 to November 29 April 5 to nd

Auerfarm

Year

2006 2007 2008

April 24 to December 13 April 24 to December 15 April 5 to nd

Wadsworth Estate

Year

2008 2009

April 25 to December 7 April 7 to nd nd = not determined (monitoring period concluded prior to the end of growing season).

31

Figure 2. Soil temperature data for the Wallingford sites in 2012 and 2013. Temperature was collected at one monitoring station (CR1), as it was assumed that the data would be representative of the three sites due to their close geographical proximity. Measurements were made at 30 cm and 50 cm depths every four hours, using an automated temperature logger.

32

Figure 3. Soil temperature data for the Auerfarm site in 2006, 2007, and 2008. Between March 2006 and October 2007, Temperature was evaluated at 50 cm using a soil thermometer. Measurements were made at least once per month, excepting September 2007. The remainder of the monitoring period was measured using an automated temperature logger. Measurements were made at 30 cm and 50 cm depths every four hours. Data Courtesy of the USDA-NRCS.

33

Figure 4. Soil temperature data for the Wadsworth Estate site in 2008 and 2009. Temperature was evaluated at both 30 and 50 cm depths. At the 50 cm depth, measurements were made at least once per month using a soil thermometer, excepting August 2008, January 2009, and February 2009. At the 30 cm depth, measurements were made at least once per month during the height of the growing season However, data was not available for the period between August 2008 and April 2009, with the exception of December 17, 2008 (0.7˚ C) and March 16, 2009 (3.7˚ C). These measurements were omitted from the figure for clarity. Data courtesy of the University of Massachusetts, Amherst.

percentile (Figure 5). The latter occurred at the end of the monitoring period. The remaining 6

months fell within the range of normal conditions (i.e., 30th and 70th percentile).

The Auerfarm site was monitored for 27 months, 14 of which fell within the range of

normal (Figure 6). Four months (May and June 2006; April 2007; and February 2008) were

above the 70th percentile. The remaining 9 months fell below the 30th percentile.

At the Wadsworth Estate site, 9 out of 15 months fell within the range of normal (Figure

7). Three months (September, and December 2008; June 2009), were above the 70th percentile,

and three were below the 30th percentile.

Saturation

The HSTS for saturation has a duration and frequency requirement. The duration

requirement is met when a water table falls within 25 cm of the soil surface for 14 consecutive

days during the growing season, with normal or drier than normal precipitation conditions. The

frequency requirement is met when this condition occurs greater than 50% of the time (i.e., 2 out

of 3 years). In 2012, two of the three Wallingford wetland monitoring stations (CR1 and TM1)

met the duration requirement, exhibiting elevated water tables for 18 and 45 consecutive days,

respectively (Table 3; Figures 10 and 12). Both of these periods occurred between October and

November, during normal and drier than normal antecedent precipitation conditions. The other

wetland station, VF1, failed to meet the duration requirement, but only by one day, with a

duration of 13 consecutive days (Figure 8). This occurred during a period of drier than normal

antecedent precipitation. None of the Wallingford wetland monitoring stations met the duration

requirement for the HSTS in 2013, with VF1 and TM1 exhibiting durations of 13 and 12

consecutive days, respectively (Table 3; Figures 8 and 12). CR1 had no days above 25 cm (Table

34

35

Figure 5. Local monthly total precipitation data for the Wallingford sites in 2012 and 2013. The “Range of Normal Conditions” refers to those values between the 30th and 70th percentiles (WETS Station: MIDDLETOWN 4 W, CT4767; Precipitation data: Meriden-Markham Municipal Airport, Meriden, CT). Three additional months of data are provided to show antecedent precipitation prior to the start of the monitoring period (March 2012).

36

Figure 6. Local monthly total precipitation data for the Auerfarm site in 2006, 2007, and 2008. The “Range of Normal Conditions” refers to those values between the 30th and 70th percentiles (WETS Station: WEST HARTFORD, CT9162; Precipitation data: Hartford-Brainard Airport, Hartford, CT). Three additional months of data are provided to show antecedent precipitation prior to the start of the monitoring period (April 2006).

Figure 7. Local monthly total precipitation data for the Wadsworth Estate site in 2008 and 2009. The “Range of Normal Conditions” refers to those values between the 30th and 70th percentiles (WETS Station: MIDDLETOWN 4 W, CT4767; Precipitation data: Meriden-Markham Municipal Airport, Meriden, CT). Three additional months of data are provided to show antecedent precipitation prior to the start of the monitoring period (April 2008).

37

3, Figure 10). Antecedent precipitation was drier than normal during these periods. At the

Auerfarm site, AF1 met the HSTS met the duration requirement in 2006, 2007, and 2008, with

elevated water tables for 72, 26, and 19 consecutive days, respectively (Table 4; Figure 14).

Antecedent precipitation was considered normal or drier than normal during each of those

periods. The wetland monitoring station at the Wadsworth Estate site met the HSTS for

saturation. WE1 met the duration requirement in both 2008 and 2009, exhibiting an elevated

water table for 18 and 52 consecutive days, respectively, with normal and drier than normal

antecedent precipitation (Table 5; Figure 16). None of the upland monitoring stations met the

HSTS for saturation.

Anaerobic Conditions

IRIS Tubes

To meet the requirements for anaerobic conditions under the HSTS using IRIS tubes, a

minimum of three out of five replicate tubes must exhibit 30% or more paint removal within a 15

cm zone of the upper 30 cm, during normal or drier than normal antecedent precipitation

conditions. Two out of the three wetland Wallingford monitoring stations (VF1 and TM1) met

the HSTS for anaerobic conditions (Table 7). Both trials (T1 and T211) conducted at these two

sites met the HSTS requirements. At CR1, only 2 out of 5 tubes met the HSTS requirements

during the trial conducted outside of the growing season. The three upland monitoring stations

exhibited a 2.5% average paint removal per tube; none of these met the HSTS requirements for

anaerobic conditions.

11 T2, which was conducted between May 2, 2013 and June 19, 2013, partially occurred within a period of precipitation above the 70th percentile (June). However, upon review of the hydrology data for VF1, water tables in June did not jump until June 7th. As such, the water table duration within June portion of the trial was only 13 days. Since 13 days does not meet the duration requirement for saturation under the HSTS, it was assumed that reduction was occurring throughout the trial, and those data were included during the analysis.

38

39

Table 3. Water table summary for each monitoring station at the Wallingford sites in 2012 and 2013. The HSTS requires that a water table be within 25 cm of the soil surface for 14 consecutive days during a period of normal or drier than normal precipitation conditions. All periods listed fall within the growing season (based on site soil temperature data). Precipitation condition was based on the Direct Antecedent Rainfall Evaluation Method (WETS Station: MIDDLETOWN 4 W, CT4767; Precipitation data: Meriden-Markham Municipal Airport, Meriden, CT).

Station Consecutive Days Within 25 cm† Month(s) Precipitation Condition

2012 2013 2012 2013 2012 2013

VF1‡ 13 13 November April Drier Drier

VF2‡ 10 6 November April Drier Drier

CR1 18 0 May - Drier -

CR2‡ 1 0 April - Drier -

TM1 45 12 Oct./Nov. Apr./May Normal/Drier Drier/Drier

TM2 28 8 November April Drier Drier † Only the longest period in a given growing season that meets antecedent precipitation requirements is shown. ‡ Site does not meet the requirements of the HSTS.

40

Table 4. Water table summary for each monitoring station at the Auerfarm site in 2006, 2007, and 2008. The HSTS requires that a water table be within 25 cm of the soil surface for 14 consecutive days during a period of normal or drier than normal precipitation conditions. All periods listed fall within the growing season (based on site soil temperature data). Precipitation condition was based on the Direct Antecedent Rainfall Evaluation Method (WETS Station: WEST HARTFORD, CT9162; Precipitation data: Hartford-Brainard Airport, Hartford, CT). Raw data courtesy of the USDA-NRCS.

Station Consecutive Days Within 25 cm† Month(s) Precipitation Condition

2006 2007 2008 2006 2007 2008 2006 2007 2008

AF1 72 26 19 O/N/D May/June April D/N/N N/N Normal

AF2 4 0 36 April May April/May Drier - Normal † Only the longest period in a given growing season that meets antecedent precipitation requirements is shown.

41

Table 5. Water table summary for each monitoring station at the Wadsworth Estate site in 2008 and 2009. The HSTS requires that a water table be within 25 cm of the soil surface for 14 consecutive days during a period of normal or drier than normal precipitation conditions. All periods listed fall within the growing season (based on redox potential data). Precipitation condition was based on the Direct Antecedent Rainfall Evaluation Method (WETS Station: MIDDLETOWN 4 W, CT4767; Precipitation data: Meriden-Markham Municipal Airport, Meriden, CT). Raw data courtesy of the USDA-NRCS.

Station Consecutive Days Within 25 cm† Month(s) Precipitation Condition

2008 2009 2008 2009 2008 2009

WE1 18 52 June April/May Normal Drier/Drier

WE2 0 32 - April/May - Drier/Drier † Only the longest period in a given growing season that meets antecedent precipitation requirements is shown.

42

Table 6. Water table summary for the Wallingford sites in 2012 and 2013, without regard for precipitation condition. All periods listed fall within the growing season (based on site soil temperature data).

Station Consecutive Days Within 25 cm Month(s)

2012 2013 2012 2013

VF1 13 28 November June/July

VF2 10 13 November June

CR1 18 17 May June

CR2 1 0 April -

TM1 45 30 Oct./Nov. June/July

TM2 28 8 November April

43

Figure 8. Hydrograph and piezometer readings for VF1 in 2012 and 2013. Manual measurements were made between March (the start of the monitoring period) and August 2012, while the remainder of the monitoring period was automated. All piezometer readings were measured manually.

44

Figure 9. Hydrograph and piezometer readings for VF2 in 2012 and 2013. Manual measurements were made between March (the start of the monitoring period) and August 2012, while the remainder of the monitoring period was automated. All piezometer readings were measured manually.

45

Figure 10. Hydrograph and piezometer readings for CR1 in 2012 and 2013. All water table readings were automated. All piezometer readings were measured manually.

46

Figure 11. Hydrograph for CR2 in 2012 and 2013. All water table readings were automated. Piezometers were not installed at this location.

47

Figure 12. Hydrograph and piezometer readings for TM1 in 2012 and 2013. All water table readings were automated. All piezometer readings were measured manually.

48

Figure 13. Hydrograph and piezometer readings for TM2 in 2012 and 2013. Both water level and piezometer readings were measured manually for the entire monitoring period.

49

Figure 14. Hydrograph for AF1 in 2006, 2007, and 2008. All measurements were manually made. Piezometers were not installed at this monitoring station. Data courtesy of the USDA-NRCS.

50

Figure 15. Hydrograph for AF2 in 2012 and 2013. All measurements were manually made. Piezometers were not installed at this monitoring station. Data courtesy of the USDA-NRCS.

51

Figure 16. Hydrograph for WE1 in 2008 and 2009. All measurements were manually made. Piezometers were not installed at this monitoring station. Data courtesy of the University of Massachusetts, Amherst.

52

Figure 17. Hydrograph for WE2 in 2008 and 2009. All measurements were manually made. Piezometers were not installed at this monitoring station. Data courtesy of the University of Massachusetts, Amherst.

Redox Potential

Under the HSTS, a soil must exhibit an Eh of less than 175 mV at pH 7 to have anaerobic

conditions. Despite monthly total precipitation generally falling within or above the range of

normal conditions, all of the mean Eh values recorded at WE1 for the 15 cm depth in 2008 fell

within the oxidizing redox potential range (with the exception of a brief period in May; Figure

18). In 2009, with the exception of brief periods in April and June, mean Eh values fell within

the reducing redox potential range (Figure 19). At the deeper depth (30 cm), mean Eh values in

2008 were well below the oxidized redox potential range (Figure 20). Similar observations were

made in 2009 at the 30 cm depth (Figure 21). These data suggest reducing conditions for the

WE1 soils for most of the growing season during the monitoring period.

Soil Morphology

General Characteristics

All wetland pedons were classified to subgroup level as Aeric Endoaquepts (Table 8).

Upland pedons had subgroup classifications of Aeric Endoaquepts (VF2), Oxyaquic Dystrudepts

(CR2), and Aquic Dystrudepts (TM2 and AF2). All sampled soils exhibited classic “ABC”

morphology. Lab-confirmed soil textures ranged from coarse sandy loam to silt loam, with most

horizons exhibiting a loam texture (Tables 9-13). Silt loam was generally observed within near-

surface horizons. Those textures with rock fragment texture modifiers were generally observed

within the substratum. Clay percentages ranged from 8.3 to 17%. Organic carbon ranged

from trace amounts to 8.1 percent, with highest values near the soil surface and decreasing with

depth. pH ranged from 4.3 to 7.0, with lowest values near the soil surface and increasing with

depth.

53

54

Table 7. IRIS tube data for wetland and upland monitoring stations at the Wallingford sites. The HSTS requires that that at least three out of five replicate tubes exhibit 30 percent or more paint removal in a 15 cm zone within the upper 30 cm of the soil. Trials were conducted within the following time periods: T1 = April 2, 2012 to May 18, 2012; T2 = May 2, 2013 to June 19, 2013; T3 = October 18, 2013 to November 8, 2013.

Site Wetland Upland

Tubes with ≥30 Percent Paint

Removal Average Removal Standard Deviation

Tubes with ≥30 Percent

Paint Removal

Average Removal

Standard Deviation

T1 T2 T1 T2 T1 T2 T3 T3 T3

VF 5/5 4/5 59.1 52.4 13.3 24.0 0/5 2.0 4.6

CR† 2/5 2/5 27.7 24.8 10.2 11.0 0/5 1.1 2.4

TM 5/5 5/5 73.8 61.6 19.7 13.6 0/5 4.6 6.2 † No trials met the requirements of the HSTS.

55

Figure 18. Mean and range of redox potential (Eh) at 15 cm for WE1 in 2008. The red, dashed line represents the Eh at which Fe(OH)3 is reduced to Fe2+ (313 mV at pH 4.7). Data courtesy of the University of Massachusetts, Amherst.

56

Figure 19. Mean and range of redox potential (Eh) at 15 cm for WE1 in 2009. The red, dashed line represents the Eh at which Fe(OH)3 is reduced to Fe2+ (313 mV at pH 4.7). Data courtesy of the University of Massachusetts, Amherst.

57

Figure 20. Mean and range of redox potential (Eh) at 30 cm for WE1 in 2008. The red, dashed line represents the Eh at which Fe(OH)3 is reduced to Fe2+ (277 mV at pH 4.7). Data courtesy of the University of Massachusetts, Amherst.

58

Figure 21. Mean and range of redox potential (Eh) at 30 cm for WE1 in 2009. The red, dashed line represents the Eh at which Fe(OH)3 is reduced to Fe2+ (277 mV at pH 4.7). Data courtesy of the University of Massachusetts, Amherst.

Matrix Color

Soils derived from red-colored parent materials typically have a hue of 7.5YR or redder.

This is consistent with the findings of this study, as the hues of all soils were 7.5YR, 5YR, or

2.5YR (Tables 9-13). In the solum, hues were either 7.5YR or 5YR, with 70 percent of the A or

Ap (surface) horizons exhibiting a 7.5YR hue. In the subsoil (B horizons), 78% of horizons

exhibited a hue of 5YR. In pedons VF1, CR2, and TM1, the hue of the substratum (C horizons)

was 2.5YR, while the remaining pedons were 5YR. Value and chroma of the surface horizons

ranged from 2.5 to 4 and 1 to 3, respectively. The value for the subsoil was 4 in all horizons,

while chroma ranged from 2 to 4. Substratum values ranged from 3 to 4 and chroma ranged

from 2 to 4. Only one pedon (WE1) exhibited a depleted matrix. This was an Ap horizon (9-15

cm; Table 13).

Redoximorphic Features

Redoximorphic features were observed within all pedons (Tables 9-13). All wetland

pedons exhibited redoximorphic features within 25 cm of the soil surface, with an average

starting depth of 9 cm. The average starting depth of redoximorphic features within upland

pedons was 36 cm. However, one upland pedon (VF2) had features starting at 14 cm (Table 9).

Soft masses of Fe accumulation were the most commonly observed feature in all pedons (Tables

9-13). Within wetland pedons, these were typically the only near-surface feature observed.

Abundance ranged from 2 to 30% (per horizon), with the highest values observed within the

subsoil and substratum. The average abundance (per horizon) within the upper 25 cm was 5%,

while for upland pedons average abundance was <1%. Contrast ranged from faint to prominent,

but was generally faint or distinct. Prominent contrast was observed in the lower subsoil or

substratum, with the exception of TM1. Depletions were observed in seven pedons (VF1, VF2,

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60

Table 8. Landscape position and classification of each pedon.

Station Landscape Position Classification†

VF1 Footslope Aeric Endoaquept

VF2 Footslope Aeric Endoaquept

CR1 Footslope Aeric Endoaquept

CR2 Footslope Oxyaquic Dystrudept

TM1 Lower Backslope Aeric Endoaquept

TM2 Lower Backslope Aquic Dystrudept

AF1 Backslope Aeric Endoaquept

AF2 Backslope Aquic Dystrudept

WE1 Backslope Aeric Endoaquept

WE2 Backslope Oxyaquic Dystrudept † All pedons are coarse-loamy, mixed, active, nonacid, and mesic, except for TM2 and AF2, which are semi-active.

61

Table 9. Soil profile descriptions for the Veteran’s Field site†.

Station Horizon Depth Matrix Texture‡ Clay O.C. pH Redoximorphic Features

% Type/Loc. Contrast

cm moist (%) % %

VF1 A 0-19 5YR 3/3 L 17.0 3.7 5.9 2 F3M/LPO D

Ap 19-32 5YR 3/4 L 14.1 1.0 5.8 6 F3M/LPO D

Bw1 32-53 5YR 4/3 L 7.9 0.2 6.3 15 F3M/MAT D

Bw2 53-70 5YR 4/4 L 12.5 0.1 6.3 5 FED/MAT D

Cd1 70-120 5YR 4/4 L 13.4 0.1 6.3 5 FED/MAT D

20 F3M/MAT D

Cd2 120-155 5YR 4/4 SIL 4.2 tr 6.5 - - -

VF2 A 0-14 5YR 3/3 SIL nd nd nd - - -

Ap 14-35 5YR 4/3 SIL nd nd nd 3 F3M/LPO D

Bw1 35-43 5YR 4/3 L nd nd nd 15 F3M/MAT D

Bw2 43-61 5YR 4/4 L nd nd nd 5 FED/LPO D

10 F3M/MAT D

5 MNM/MAT P

Cd1 61-85 2.5YR 4/4 L nd nd nd 2 F3M/MAT D

Cd2 85-100 5YR 4/4 L nd nd nd 10 F3M/MAT D † Soil profile descriptions follow terminology described in Field Book for Describing and Sampling Soils, Version 3.0

(Shoeneberger et al. 2012). ‡ Texture for VF1 is based on laboratory testing, while VF2 is based on field texture. nd = not determined. tr = trace.

62

Table 10. Soil profile descriptions for the Cooke Road site†.

Station Horizon Depth Matrix Texture‡ Clay O.C. pH Redoximorphic Features

% Type/Loc. Contrast

cm moist (%) % %

CR1 A1 0-20 7.5YR 3/2 SIL 15.3 2.7 5.6 - - -

A2 20-28 7.5YR 3/2 L 16.4 2.0 5.7 3 F3M/APF F

8 FED/MAT F

Bw1 28-35 5YR 4/3 (45) L 9.1 0.5 5.8 1 MNM/MAT D

7.5YR 4/3 (45) 4 FED/APF F

5 F3M/MAT F

Bw2 35-61 5YR 4/3 L 9.1 0.3 6.2 5 MNM/MAT D

5 F3M/MAT D

2 FED/APF F

Cd1 61-72 5YR 4/3 COSL 10.1 0.1 6.5 4 MNM/MAT D

20 F3M/MAT F

Cd2 72-155 5YR 3/3 COSL 10.5 tr 6.3 - - -

CR2 Ap 0-13 7.5YR 2.5/2 SIL nd nd nd - - -

BA 13-30 7.5YR 3/3 FSL nd nd nd - - -

Bw 33-58 5YR 4/3 GRSL nd nd nd 5 F3M/MAT D

BC 58-80 2.5YR 4/3 VGSL nd nd nd 5 F3M/MAT P † Soil profile descriptions follow terminology described in Field Book for Describing and Sampling Soils, Version 3.0

(Shoeneberger et al. 2012). ‡ Texture for CR1 is based on laboratory testing, while CR2 is based on field texture. nd = not determined. tr = trace.

63

Table 11. Soil profile descriptions for the Tyler Mill site†.

Station Horizon Depth Matrix Texture‡ Clay O.C. pH Redoximorphic Features

% Type/Loc. Contrast

cm moist (%) % %

TM1 A 0-10 7.5YR 3/1 MKL 15.0 8.1 4.9 - - -

Ap 10-24 7.5YR 3/1 L 15.4 2.8 6.0 2 F3M/MAT P

Bw1 24-36 7.5YR 4/3 L 10.8 0.5 6.5 5 F3M/APF P

Bw2 36-52 7.5YR 4/3 L 11.4 0.2 6.6 10 F2M/MAT F

15 F3M/APF P

Cd1 52-78 5YR 4/3 SL 13.8 0.1 7.0 2 MNM/MAT P

Cd2 78-200 2.5YR 4/2 SL 13.5 tr 7.0 - - -

TM2 Ap 0-24 7.5YR 3/2 SIL nd nd nd - - -

Bw 24-51 5YR 4/4 GRFSL nd nd nd - - -

Cd 51-80 5YR 4/4 GRSL nd nd nd 5 F3M/MAT D

2 FED/MAT D

2 MNM/MAT P † Soil profile descriptions follow terminology described in Field Book for Describing and Sampling Soils, Version 3.0

(Shoeneberger et al. 2012). ‡ Texture for TM1 is based on laboratory testing, while TM2 is based on field texture. nd = not determined. tr = trace.

64

Table 12. Soil profile descriptions for the Auerfarm site†. Data courtesy of the USDA-NRCS.

Station Horizon Depth Matrix Texture‡ Clay O.C. pH Redoximorphic Features

% Type/Loc. Contrast

cm moist (%) % %

AF1 Ap 0-15 7.5YR 3/2 SIL nd nd nd - - -

Bw 15-41 7.5YR 4/4 SIL nd nd nd 5 F3M/MAT D

5 FED/MAT D

BC 41-51 5YR 4/3 GRL nd nd nd 5 F3M/MAT D

5 FED/MAT D

Cd 51-102 5YR 4/3 GRL nd nd nd - - -

AF2 A1 0-3 5YR 2.5/1 SIL nd nd nd - - -

A2 3-20 5YR 3/3 SIL nd nd nd - - -

Bw1 20-36 7.5YR 4/6 SIL nd nd nd - - -

Bw2 36-46 5YR 4/4 GRSIL nd nd nd - - -

Cd1 46-76 5YR 4/4 GRL nd nd nd 5 F3M/MAT P

10 FED/MAT D

Cd2 76-102 5YR 4/3 SIL nd nd nd 20 F3M/MAT P

30 FED/MAT D † Soil profile descriptions follow terminology described in Field Book for Describing and Sampling Soils, Version 3.0

(Shoeneberger et al. 2012). ‡ Both AF1 and AF2 are based on field texture. nd = not determined. tr = trace.

65

Table 13. Soil profile descriptions for the Wadsworth Estate site†. Data for WE2 courtesy of the USDA-NRCS.

Station Horizon Depth Matrix Texture‡ Clay O.C. pH Redoximorphic Features

% Type/Loc. Contrast

cm moist (%) % %

WE1 A 0-9 7.5YR 3/2 L 15.7 2.9 4.9 2 F3M/LPO D

5 F3M/LPO F

Ap 9-15 7.5YR 4/2 L 13.7 2.0 4.7 2 F3M/LPO D

5 F3M/LPO F

Bw1 15-29 5YR 4/3 L 9.5 0.5 5.1 2 MNM/MAT P

10 F3M/MAT F

Bw2 29-46 5YR 4/3 L 15.6 0.4 5.3 2 MNM/MAT P

5 F3M/MAT P

20 F3M/MAT F

BC 46-66 5YR 4/3 L 14.7 0.2 5.9 5 FED/APF F

30 F3M/MAT D

Cd1 66-130 5YR 3/3 COSL 8.3 0.1 6.6 2 F3M/MAT D

Cd2 130-155 5YR 3/2 L 11.6 0.1 7.0 1 F3M/MAT P

WE2 Oe 0-5 - - nd nd nd - - -

Ap 5-23 7.5YR 3/3 SIL nd nd nd - - -

Bw1 23-38 5YR 4/3 L nd nd nd - - -

Bw2 38-61 5YR 4/3 L nd nd nd 5 F3M/MAT F

Cd 61-90 5YR 4/3 FSL nd nd nd 5 F3M/MAT P † Soil profile descriptions follow terminology described in Field Book for Describing and Sampling Soils, Version 3.0

(Shoeneberger et al. 2012). ‡ Texture for WE1 is based on laboratory testing, while WE2 is based on field texture. nd = not determined.

CR1, TM2, AF1, AF2, and WE1). They were typically expressed below 40 cm, with the

exception of the CR1pedon, which had depletions within 25 cm (Table 10). Abundance ranged

from 2 to 30%, with the highest figures expressed in the substratum (Tables 9-13). Contrast

was faint or distinct. Mn concentrations were observed in five pedons (VF2, CR1, TM1, TM2,

and WE1; Figures 9, 10, 11, and 13). These concentrations were typically observed below 25

cm, with the exception of the WE1 pedon where they occurred as high as 15 cm. Abundance of

Mn concentrations ranged from 2 to 5%, with no significant difference between upland and

wetland pedons. Contrast was prominent in all cases.

Vegetation

Cover data collected from the Veteran’s Field site shows that a hydrophytic plant

community was present at both monitoring stations (Table 14). At VF1, dominant vegetation

included silky dogwood (Cornus amomum), blue vervain (Verbena hastata), and an unknown

member of the Poaceae family. At VF2, dominant vegetation included silky dogwood and reed

canarygrass (Phalaris arundinacea).

At the Cooke Road site, VF1 contained a hydrophyte dominant community, while VF2

did not (Table 15). Dominant vegetation at VF1 included red maple (Acer rubrum), American

elm (Ulmus americana), black cherry (Prunus serotina), winterberry (Ilex verticillata), Virginia

creeper (Parthenocissus quinquefolia), jewelweed (Impatiens capensis), and poison ivy

(Toxicodendron radicans), while VF2 was dominated by red maple, black cherry, white wood

aster (Eurybia divaricata), Canada mayflower (Maianthemum canadense), and shagbark hickory

(Carya ovata).

Both Tyler Mill monitoring stations contained a hydrophyte dominant plant community

(Table 16). TM1 was characterized by red maple, green ash (Fraxinus pennsylvanica),

winterberry, spicebush (Lindera benzoin), skunk cabbage (Symplocarpus foetidus), and poison

66

ivy. TM2 is characterized by red maple, sugar maple, ironwood (Carpinus caroliniana),

spicebush, and New York fern (Parathelypteris noveboracensis).

At the Auerfarm site, AF1 supported a hydropytic plant community, and AF2 did not

(Table 17). Dominant plant species at AF1 included red maple, spicebush, trout lily

(Erythronium americanum), and Canada mayflower. AF2 was characterized by red maple, sugar

maple, white oak (Quercus alba), red oak (Quercus rubra), spicebush, Canada mayflower, and

wood anemone (Anemone quinquefolia).

Cover data for the Wadsworth Estate site indicates that both monitoring stations

supported a hydrophytic plant community (Table 18). WE1 was characterized by red maple,

spicebush, New York fern, and fox grape (Vitis labrusca). WE2 wass characterized by red

maple, spicebush, Canada mayflower, and New York fern.

67

68

Table 14. Dominant vegetation for the Veteran’s Field site.

Station Stratum Species Indicator Status† Hydrophyte Dominant?

VF1 Canopy - - Yes

Sapling/Shrub Swida amomum FACW

Herbaceous Verbena hastata FACW

Poaceae sp.‡ -

Woody Vines - -

VF2 Canopy - - Yes

Sapling/Shrub Swida amomum FACW

Herbaceous Phalaris arundinacea FACW

Woody Vines - - † Indicator status was obtained from the National Wetland Plant List (Lichvar et al., 2014). ‡ This species could not be identified. It was omitted from the determination of the plant community, as it would have no bearing on the outcome.

69

Table 15. Dominant vegetation for the Cooke Road site.

Station Stratum Species Indicator Status† Hydrophyte Dominant?

CR1 Canopy Acer rubrum FAC Yes

Ulmus americana FACW

Sapling/Shrub Prunus serotina FACU

Ilex verticillata FACW

Ulmus americana FACW

Herbaceous Parthenocissus quinquefolia FACU

Impatiens capensis FACW

Woody Vines Toxicodendron radicans FAC

Parthenocissus quinquefolia FACU

CR2 Canopy Acer rubrum FAC No

Sapling/Shrub Prunus serotina FACU

Herbaceous Eurybia divaricata UPL

Prunus serotina FACU

Maianthemum canadense FAC

Carya ovata FACU

Woody Vines - - † Indicator status was obtained from the National Wetland Plant List (Lichvar et al., 2014).

70

Table 16. Dominant vegetation for the Tyler Mill site.

Station Stratum Species Indicator Status† Hydrophyte Dominant?

TM1 Canopy Acer rubrum FAC Yes

Fraxinus pennsylvanica FACW

Sapling/Shrub Ilex verticillata FACW

Lindera benzoin FACW

Herbaceous Symplocarpus foetidus OBL

Woody Vines Toxicodendron radicans FAC

TM2 Canopy Acer rubrum FAC Yes

Sapling/Shrub Acer saccharum FACU

Carpinus caroliniana FAC

Lindera benzoin FACW

Herbaceous Lindera benzoin FACW

Parathelypteris noveboracensis FAC

Carpinus caroliniana FAC † Indicator status was obtained from the National Wetland Plant List (Lichvar et al., 2014).

71

Table 17. Dominant vegetation for the Auerfarm site. Data courtesy of the USDA-NRCS.

Station Stratum Species Indicator Status† Hydrophyte Dominant?

AF1 Canopy Acer rubrum FAC Yes

Sapling/Shrub Lindera benzoin FACW

Herbaceous Erythronium americanum UPL

Maianthemum canadense FAC

Woody Vines - -

AF2 Canopy Acer rubrum FAC No

Acer saccharum FACU

Quercus alba FACU

Quercus rubra FACU

Sapling/Shrub Lindera benzoin FACW

Herbaceous Maianthemum canadense FAC

Anemone quinquefolia FACU

Woody Vines - - † Indicator status was obtained from the National Wetland Plant List (Lichvar et al., 2014).

72

Table 18. Dominant vegetation for the Wadsworth Estate site. Data courtesy of the USDA-NRCS.

Station Stratum Species Indicator Status† Hydrophyte Dominant?

WE1 Canopy Acer rubrum FAC Yes

Sapling/Shrub Lindera benzoin FACW

Herbaceous Parathelypteris noveboracensis FAC

Woody Vines Vitis labrusca FACU

WE2 Canopy Acer rubrum FAC Yes

Sapling/Shrub Lindera benzoin FACW

Herbaceous Maianthemum canadense FAC

Parathelypteris noveboracensis FAC

Woody Vines - † Indicator status was obtained from the National Wetland Plant List (Lichvar et al., 2014).

DISCUSSION

Hydric Soil Technical Standard

Veteran’s Field

Based on the data presented above, neither monitoring station at the Veteran’s Field site

explicitly met the HSTS. VF1 met the standard for anaerobic conditions in both 2012 and 2013,

but did not meet the saturation standard in either year. In both 2012 and 2013, the duration was

13 consecutive days, which is 1 day short of the HSTS duration requirement for saturation.

Antecedent precipitation condition appears to have had a significant impact on these data.

In 2012, monthly total precipitation was below the range of normal for the period where the

longest duration was recorded. It should also be noted that there was a 1 day period at the end of

that 13 day duration where water tables dropped below 25 cm before recovering the following

day. Had the water table remained above 25 cm during this period, it would have extended the

duration an additional 5 days, which would meet the HSTS duration requirements. In 2013,

monthly total precipitation was below the range of normal conditions in March, April, and May

of 2013 (Figure 5). In June and July, precipitation spiked with values of 24.41 cm and 16.81 cm,

respectively. Per NTCHS (2007), these two months had to be omitted from the dataset, which

eliminated the longest duration of near-surface water table readings for that year (28 consecutive

days; Table 6). Based on data from the Auerfarm and Wadsworth Estate sites, which had a more

normal precipitation distribution during their respective monitoring periods and met the HSTS,

we argue that had antecedent precipitation been closer to the range of normal conditions, it is

likely VF1 would have met the duration requirements for saturation.

An intriguing observation at VF1 concerns the relationship between water table duration

and soil reduction. The longest water table durations at VF1 do not correspond with the time

73

period during which IRIS tube trials were conducted. It has been demonstrated, however, that

reduction can exist without the presence of a near-surface water table. In many cases, capillary

action may cause water to persist above the water table, resulting in a phenomenon known as the

capillary fringe. Linn and Doran (1984) found a linear relationship between water-filled pore

space and the relative amount of aerobic microbial activity. Above 60% water-filled pore space,

aerobic microbial activity decreased, likely the result of limited oxygen. The presence of the

capillary fringe may provide the requisite amount of water to maintain reducing conditions in the

soil profile, particularly in finer-textured soils (like those found in this study), where tensional

forces are higher.

Cooke Road

As with the Veteran’s Field site, neither monitoring station at the Cooke Road site met

the HSTS. CR1 met the duration requirement for saturation in 2012, but not 2013. This is likely

attributable to the absence of normal antecedent precipitation between March and July of 2013

(Figure 5). As noted in the discussion of VF1, monthly total precipitation was below the range

of normal conditions in March, April, and May of 2013. In June and July, precipitation values

were above the range of normal, which, again, eliminated two months from the data set where

duration was the longest (18 consecutive days; Table 6). Had antecedent moisture been within

the range of normal, it is likely this site would have met the duration requirement in 2013.

CR1 also did not meet the standard for anaerobic conditions, as both IRIS tube trials were

below the HSTS requirements (at least 3 out of 5 tubes must display 30% paint removal within a

15 cm zone of the upper 30 cm). Only 2 out of 5 tubes met paint removal requirements in each

trial. However, Rabenhorst (2008) noted that the HSTS requirement for paint removal is likely

more conservative due to the fact that most studies would use visual estimation versus a scanning

74

device to quantify paint removal. Castenson and Rabenhorst (2006) reported that paint removal

values of 25% or more represented reducing conditions 100% of the time when compared with

Eh data. In addition, paint removal values between 10% to 25% represented reducing conditions

81% to 90% of the time. As we used a more accurate method of quantification than visual

estimation (see Rabenhorst, 2012), it is our opinion that these interpretations could be applied

with reasonable accuracy. T1 had two additional tubes with values above 25%, while T2 had

one additional tube above 20%. Using the interpretations described in Castenson and Rabenhorst

(2006), CR1 would be considered reducing and would meet the HSTS for anaerobic conditions.

Tyler Mill

At the Tyler Mill site, neither TM1 nor TM2 met the HSTS. TM1 was the “wettest” site

monitored in 2012; however, it did not meet the duration requirement in 2013, and thus did not

meet the frequency requirement. This is likely attributable to the absence of normal antecedent

precipitation conditions between March and July of 2013 (Figure 6). If June and July were

included, TM1 would meet the duration requirement for 2013 (30 consecutive days), and

therefore, meet the frequency requirement as well (Table 6). As with the Veteran’s Field and

Cooke Road sites, we argue that if precipitation was closer to the range of normal conditions,

TM1 would meet the duration and frequency requirements, thus meeting the HSTS. It should

also be noted that the determination of the growing season could play a factor in the duration for

2013. As soil temperature is a more conservative metric for determining the growing season,

there is a potential that microbial activity may be occurring prior to the start date derived from

this study. There are several days of water table data in 2013 immediately preceding the start of

the growing season where water levels are within 25 cm. It is possible that the duration

75

requirement would be met, if the growing season was extended. Unfortunately, IRIS tube and

Eh data for the entire monitoring period would be required, which are not available.

It is important to note that TM1 met the standard for anaerobic conditions for both IRIS

tube trials. When taking into consideration the absence of normal antecedent precipitation

conditions, it is our opinion that TM1 is functioning as a hydric soil, despite it not explicitly

meeting the HSTS.

TM2, surprisingly, met the duration requirement for saturation in 2012 under a drier than

normal precipitation condition. It did not meet the requirement in 2013, even when the portion

of the data set omitted from analysis was included (Table 6). The site did not meet the

requirements for anaerobic conditions.

Auerfarm

No reduction data was collected at this site, so neither AF1 nor AF2 can officially meet

the HSTS. However, the data collected does provide additional insight relative to the hydrology

of these sites. AF1 met the duration requirement for saturation each of the three years during the

monitoring period, and thus, meets the HSTS requirements for saturation. These data were

collected during a period much closer the range of normal conditions for antecedent

precipitation, which may provide a window into what the normal water table patterns and

durations within the Wallingford sites (which were largely collected during abnormal antecedent

precipitation conditions), would look like. In addition, the presence of reducing conditions at

other wetland monitoring stations with weaker hydrology indicates that AF1 would likely meet

the HSTS for anaerobic conditions, and would thus meet the requirements of the HSTS.

AF2, as expected, did not meet the HSTS. However, it did meet the duration standard in

2008 under normal precipitation conditions. As noted above, no reduction data were collected to

76

determine the presence of anaerobic conditions, but given the absence of a near-surface water

table at the required frequency and the absence of a hydrophytic plant community, it is unlikely

that reduction would be observed.

Wadsworth Estate

At the Wadsworth Estate, WE1 met the HSTS, while WE2 did not. WE1 met the

duration requirement for saturation in both 2008 and 2009, and thus, met the saturation standard.

In addition, WE1 met the standard for reduction, with Eh values below the requisite voltage to

induce reduction of iron for significant portions of the growing season. It should be noted,

however, that the pedon associated with the monitoring station contained a depleted matrix

(Table 13). The presence of this feature precludes the soil from being “problematic.” This was

missed during initial field sampling; otherwise, an alternative site would have been selected.

WE2 did not meet the duration requirement for saturation in 2008, but did in 2009 (under

drier than normal precipitation conditions). No Eh data were collected for the upland pedon;

however, given the lack of a near-surface water table with the requisite frequency, and the

presence of a non-hydrophytic plant community, it is likely that WE2 is not functioning as a

hydric soil.

Field Indicators of Hydric Soils and Soil Morphology

All five wetland monitoring stations and one upland station (VF2) met TF2 (Table 19).

In contrast, only one monitoring station (AF1) met F21. AF1 also met TF2. There were two

additional monitoring stations that met multiple indicators. In addition to TF2, TM1 also met

indicator F6 (i.e., Redox Dark Surface), while WE1 also met the requirements for F3 (i.e.,

Depleted Matrix). With regards to the former, TM1 had the highest organic carbon value;

77

78

Table 19. Hydric soil indicators associated with each monitoring station.

Station Hydric Soil Indicator(s)

VF1 TF2

VF2 TF2

CR1 TF2

CR2 None

TM1 TF2, F6

TM2 None

AF1 TF2, F21

AF2 None

WE1 TF2, F3

WE2 None

nearly three times greater than other monitoring stations that were evaluated (Table 11). This is

likely indicative of less soil erosion from overland runoff. WE1 would not be considered

“problematic” due to the presence of a depleted matrix, and neither TF2 nor F21 would apply.

It appears that the two primary limiting factors in determining the applicability of TF2 or

F21 are related to abundance and contrast of redoximorphic features. TF2 requires 2% or more

redox depletions and/or redox concentrations occurring as soft masses and/or pore linings

occurring within a layer at least 10 cm thick within the upper 30 cm of the soil. There is no

contrast requirement. While all wetland monitoring stations met TF2, the average abundance per

horizon within 30 cm of the soil surface was 8.3% and contrast ranged from faint to prominent

(Tables 9-13). These data, along with the false-positive at VF2, suggest that abundance

requirements are too low, and TF2 is likely too inclusive.

F21 requires 10% or more depletions and/or distinct or prominent redox concentrations

occurring as soft masses or pore linings in a layer 10 cm thick starting within 25 cm. There were

three monitoring stations (CR1, AF1 and WE1) that met the 10% abundance requirement (Tables

10, 12, and 13). AF1 also met the contrast requirement; however, both CR1 and WE1 exhibited

faint contrast in the layer that met the F21 abundance requirements. For wetland monitoring

stations, the average abundance per horizon within 25 cm of the soil surface was 5.2% and

contrast ranged from faint to prominent (Tables 9-13). Based on these data, we argue that the

abundance and contrast requirements for F21 are too restrictive for use in MLRA 145.

Data Issues

Hydrology Data

Water table measurements at several monitoring stations were conducted using

capacitance water level recorders. Larson and Runyan (2009) observed several issues with these

79

instruments that ultimately resulted in inaccurate measurements. Issues are related to several

variables; however, calibration methods appeared to be the greatest source of error, with

observed values between 11 mm and 288 mm. As noted in the methodology of this manuscript,

manual readings were made during installation and removal of the water level recorders, as well

as other times throughout the year to confirm the automated readings. Logger readings were

usually within a couple centimeters of the manual measurement. We feel confident that the data

presented are accurate enough to make determinations relative to the presence of a near-surface

seasonally high water table.

Redox Potential

For many years, scientists have measured redox potential using a standard multimeter.

These devices have been selected due to their lower cost compared with high-resistance,

laboratory-grade equipment (Rabenhorst, 2009). However, Rabenhorst, Hively, and James

(2009) observed that devices with lower input resistance (such as a standard multimeter) yield a

high degree of “drift” when recording voltage readings. Drift is caused by higher current flow,

which promotes the transfer of electrons, and can change the electrochemistry of the soil

immediately surrounding the electrodes (Rabenhorst, 2009). This drift has been observed to fall

between 100 mV to 200 mV, and can result in incorrect interpretations relative to the presence of

reducing conditions. Rabenhorst (2009) found that the drift always moves towards a raw voltage

of zero, and that Eh values that fall between the corrected voltage for a specific pH and the Fe

stability line were most likely drifting across the stability line and could yield erroneous results.

Eh values outside of these areas would still represent reducing or oxidizing conditions. As

noted in the methodology of this manuscript, raw voltage readings taken at WE1 were collected

using a standard multimeter, and are therefore subject to the issues described above. Despite

80

potential issues with the data, however, the issue is moot, as WE1 contained a depleted matrix

and is not considered “problematic.”

81

CONCLUSION AND RECOMMENDATIONS

This study investigated problematic hydric soils derived from red-colored glacial till at

five sites within MLRA 145. The overarching goals of this investigation were to 1) determine

the utility of hydric soil indicator F21 and the former indicator TF2 in the glaciated northeast

region, and 2) make recommendations to the NEHSTC regarding future development of a

region-specific hydric soil indicator. The HSTS was implemented to determine whether sampled

soils met the requirements for saturation and anaerobic conditions (and thus, the requirements of

a hydric soil under the USDA-NRCS definition).

The study yielded some interesting results. Only one monitoring station met the

requirements of the HSTS explicitly (WE1); however, the associated pedon contained a depleted

matrix, which would preclude the site from being “problematic.” Of the remaining wetland

monitoring stations, one (CR1) did not meet the HSTS requirements for anaerobic conditions.

This is likely due to a more conservative interpretation of IRIS tube quantification by the

NTCHS. Research has shown that the paint removal values at CR1 are indicative of reduction.

Two other monitoring stations (VF1 and TM1) did not meet the HSTS requirements for

saturation. This is potentially the result of atypical precipitation conditions, as 2012 was

considerably drier than normal, and a significant portion of the growing season in 2013 had to be

omitted due to above-average precipitation. AF1 lacked reduction data, but had requisite

duration and frequency to meet saturation. This monitoring station would potentially meet the

HSTS. It is our opinion that all wetland monitoring stations, despite many not explicitly meeting

the HSTS, are functioning as hydric soils. None of the upland monitoring stations met the

HSTS.

82

Evaluation of the monitoring stations relative to hydric soil indicators revealed that all

five wetland monitoring stations and one upland station met TF2. Conversely, only one

monitoring station met F21, which also met TF2. Two stations that met TF2 also met other

currently accepted hydric soil indicators. These results indicate that F-21 is not suitable for use

in MLRA 145, which is of concern as it currently the only formally accepted indicator for use

within the region. In addition, TF2 may be too conservative for use, as it resulted in a false-

positive at VF2.

While it can be argued that all pedons are functioning as hydric soils, it is still concerning

that none of the wetland monitoring stations explicitly met the HSTS (excluding WE1).

However, what is clear is the fact that the TF2 and F21 indicators do not work, and we

recommended that a new indicator be considered within the region. Based on the data collected

in this study, changes should be made to abundance and contrast, which were found to be the

limiting factors with both TF2 and F21. We recommend abundance requirements be reduced to

5%. This will be more inclusive than F21, while being restrictive enough to avoid the false-

positive scenario that was documented at VF2 with the TF2 indicator. In addition, we

recommend that redoximorphic features have no contrast requirement, as observed

redoximorphic features spanned all three contrast categories. Our recommended verbiage is as

follows:

A layer derived from red parent materials that is at least 15 cm (6 inches) thick,

starting within 25 cm (10 inches) of the soil surface with a 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 5% or more depletions and/or redox concentrations that are faint,

distinct, or prominent, occurring as soft masses or pore linings.

83

Continued research is needed to fully understand the nature of these soils. Specifically,

monitoring of existing sites should continue, in order to strengthen our understanding of the

hydromorphological characteristics associated with these soils and obtain a longer record of

hydrologic conditions. This will provide more insight into how these soils respond under normal

antecedent moisture conditions. In addition, the study should be expanded to include additional

parent materials, including glaciofluvial, alluvial, and glaciolacustrine. This study has focused

on till landscapes, and it is unknown if the TF2 or F21 indicators are effective in other parent

materials. Also, future research should look at the dissolved oxygen content of groundwater, to

determine the potential effect of lateral flow on reduction. Lastly, there appears to be potential

with Mn-hydrology relationships. During sampling efforts, these features were observed in

several pedons and those data that we do have appear to correlate well with the water table.

Subsequent field visits have revealed that all sampled wetland pedons have these features.

Additional research should be conducted looking specifically at these features.

The results of this study highlight the need for vigilance when conducting work in MLRA

145. Soil is a dynamic resource that lies on a continuum across the landscape. There is likely no

single indicator that can be applied in all cases with 100% certainty of success. Best professional

judgment remains critical, and scientists must use all the resources in their toolbox. We

recommended that scientists observe and document multiple pits to ensure what is seen in one pit

is representative for the site. In addition, observed samples should be exposed to air for a period

of time, particularly if the soil is waterlogged. This will maximize the expression of those

redoximorphic features present in the soil. Lastly, in the early growing season, alpha, alpha’-

dipyridyl can be used in lieu of more expensive and time consuming methods (e.g., IRIS tubes

and Eh data) to document the presence of reducing conditions.

84

LITERATURE CITED

Blodgett, R. H., Crabaugh, J. P., & McBride, E. F. (1993). The Color of Red Beds – A Geologic Perspective. In J. M. Bingham & E. J. Ciolkosz (Eds.), Soil Color [SSSA Special Publication 31] (pp. 127-159). Madison, WI: Soil Science Society of America.

Castenson, K. L., & Rabenhorst, M. C. (2006). Indicator of Reduction in Soil (IRIS): Evaluation

of a New Approach for Assessing Reduced Conditions in Soil. Soil Science Society of America Journal, 70, 1222-1226.

Connecticut Department of Environmental Protection, & United States Department of

Agriculture, Natural Resources Conservation Service. (2006). Soil Catenas of Connecticut. Retrieved from USDA-NRCS website http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_010969.pdf

Cowardin, L. M., Carter, V., Golet, F. C., & LaRoe, E. T. (1979). Classification of Wetlands and

Deepwater Habitats of the United States (United States Fish and Wildlife Service Report No. FWS/OBS/-79/31). Washington, DC: United States Government Printing Office.

Craft, C. B. (2001). Biology of Wetland Soils. In J. L. Richardson & M. J. Vepraskas (Eds.),

Wetland Soils: Genesis, Hydrology, Landscapes, and Classification (pp. 107-136). Boca Raton, FL: CRC Press.

Elless, M. P., & Rabenhorst, M. C. (1994). Hematite in the shales of the Triassic Culpepper

Basin of Maryland. Soil Science, 158(2), 150-154. Elless, M. P., Rabenhorst, M. C., & James, B. R. (1996). Redoximorphic features in soils of the

Triassic Culpepper Basin. Soil Science, 161(1), 58-69. Environmental Laboratory. (1987). Corps of Engineers Wetlands Delineation Manual (Technical

Report Y-87-1). Vicksburg, Mississippi: U. S. Army Engineer Waterways Experiment Station.

Federal Water Pollution Control Act, 33, Selected Environmental Law Statutes § 1251-1387

(Thomson Reuters - Westlaw 2013-2014).

85

Fey, M. V. (1983). Hypothesis for the pedogenic yellowing of red soil materials. Proceedings of the 10th National Congress, East London, 1981 (Soil Science Society Southern Africa Technical Communication 180, pp. 130–136). Pretoria: Department of Agriculture.

Hubert, J. F., Reed, A. A., Dowdall, W. L., & Gilchrist, J. M. (1978). Guide to the Mesozoic

Redbeds of Central Connecticut (Guidebook No. 4). Hartford, CT: State Geological and Natural History Survey of Connecticut, Department of Environmental Protection.

Jenkinson, B. J., & Franzmeier, D. P. (2006). Development and Evaluation of Iron-Coated Tubes

that Indicate Reduction in Soils. Soil Science Society of America Journal, 70, 183-191. Larson, J. S., & Kusler, J. A. (1979). Preface. In P. E. Greeson, J. R. Clark & J. E. Clark (Eds.),

Wetland Functions and Values: The State of Our Understanding. Minneapolis, MN: American Water Resources Association.

Lee, C. (1992). Controls on Organic Carbon Preservation: The Use of Stratified Water Bodies to

Compare Intrinsic Rates of Decomposition in Oxic and Anoxic Systems. Geochimica et Cosmochimica Acta, 56, 3323-3325.

Lichvar, R. W., Butterwick, M., Melvin, N. C., & Kirchner, W. N. (2014). The National Wetland

Plant List: 2014 Update of Wetland Ratings. Phytoneuron, 41, 1-42. Linn, D. M., & Doran, J. W. (1984). Effect of Water-Filled Pore Space on Carbon Dioxide and

Nitrous Oxide Production in Tilled and Nontilled Soils. Soil Science Society of America Journal, 48, 1267-1272.

Mausbach, M. J., & Parker, W. B. (2001). Background and History of the Concept of Hydric

Soils. In J. L. Richardson & M. J. Vepraskas (Eds.), Wetland Soils: Genesis, Hydrology, Landscapes, and Classification (pp. 19-34). Boca Raton, FL: CRC Press.

Merguerian, C., & Sanders, J. E. (2010). Trips on the Rocks, Guide 22: New Haven-East Haven-

Branford Area, Connecticut. Retrieved from Duke Geological Laboratory website: http://dukelabs.com/Publications/PubsPdf/On_the_Rocks/LocalityListBlurb.htm

Metzler, K. J. & Tiner R. W. (1992). Wetlands of Connecticut. State Geological and Natural

History Survey of Connecticut, in Cooperation with the U.S. Fish and Wildlife Service National Wetlands Inventory.

86

Mitsch, W. J., & Gosselink, J. G. (2007). Wetlands. 4th Edition. Hoboken, NJ: John Wiley & Sons, Inc.

Mokma, D. L. (1993). Color and Amorphous Materials in Spodosols from Michigan. Soil

Science Society of America Journal, 57, 125-128. Mokma, D. L., & Sprecher, S. W. (1994). Water table depths and color patterns in soils

developed from red parent materials in Michigan, USA. Catena, 22, 287-298. Moya, O. L., & Fono, A. L. (2011). Federal Environmental Law: The User's Guide (3rd ed.). St.

Paul, MN: West Publishing Company. National Technical Committee for Hydric Soils. (2007). The Hydric Soil Technical Standard

(Hydric Soil Technical Note 11). Retrieved from USDA-NRCS website: http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_051608.pdf

Ponnamperuma, F.N. (1972). The chemistry of submerged soils. Advances in Agronomy, 24, 29-

96. Rabenhorst, M. C. (2008). Protocol for Using and Interpreting IRIS Tubes. Soil Survey Horizons,

49, 74-77. ______. (2009). Making Soil Oxidation-Reduction Potential Measurements using Multimeters.

Soil Science Society of America Journal, 73, 2198-2201. ______. (2012). Simple and Reliable Approach for Quantifying IRIS Tube Data. Soil Science

Society of America Journal, 76, 307-308. Rabenhorst, M. C., & Burch, S. N. (2006). Synthetic Iron Oxides as an Indicator of Reduction in

Soils (IRIS). Soil Science Society of America Journal, 70, 1227-1236. Rabenhorst, M. C., Hively, W. D., & James, B. R. (2009). Measurements of soil redox potential.

Soil Science Society of America Journal, 73, 668–674. Rabenhorst, M. C. & Parikh, S. (2000). Propensity of Soils to Develop Redoximorphic Color

Changes. Soil Science Society of America Journal, 64, 1904-1910.

87

Schwertmann, U. (1993). Relations Between Iron Oxides, Soil Color, and Soil Formation. In J. M. Bingham & E. J. Ciolkosz (Eds.), Soil Color (SSSA Special Publication 31, pp.127-159). Madison, WI: Soil Science Society of America.

Schwertmann, U., & Taylor, R. M. (1989). Iron Oxides. In Minerals in Soil Environments (2nd

Edition, SSSA Book Series No. 1). Madison, WI: Soil Science Society of America. Schoeneberger, P. J., Wysocki, D. A., Benham, E. C., & Soil Survey Staff. (2012). Field Book

for Describing and Sampling Soils (Version 3.0). Lincoln, NE: Natural Resources Conservation Service, National Soil Survey Center.

Soil Survey Staff. (2014). Keys to Soil Taxonomy (12th Edition). Washington, DC: United States

Department of Agriculture, Natural Resources Conservation Service. Sprecher, S. W. (2008). Installing Monitoring Wells in Soils (Version 1.0). Lincoln, NE: Natural

Resources Conservation Service, National Soil Survey Center. Sprecher, S. W., & Warne, A. G. (2000). Accessing and Using Meteorological Data to Evaluate

Wetland Hydrology (ERDC/EL TR-WRAP-00-1). Vicksburg, MS: U. S. Army Engineer and Development Center.

Tiner, R. W. (1999). Wetland Indicators: A Guide to Wetland Identification, Delineation,

Classification, and Mapping. Boca Raton, FL: CRC Press. Torrent, J., & Schwertmann, U. (1987). Influence of Hematite on the Color of Red Beds. Journal

of Sedimentary Petrology, 57(4), 682-686. United States Army Corps of Engineers. (2012). Regional Supplement to the Corps of Engineers

Wetland Delineation Manual: Northcentral and Northeast Region (Version 2.0, ERDC/EL TR-12-1). J. S. Wakeley, R. W. Lichvar, C. V. Noble & J. F. Berkowitz (Eds.). Vicksburg, MS: U.S. Army Engineer Research and Development Center.

United States Department of Agriculture, Natural Resources Conservation Service. (n.d.).

Odyssey Water Level Loggers Quick Setup. Unpublished document, USDA-NRCS.

88

______. (2006). Land Resource Regions and Major Land Resource Areas of the United States, the Caribbean, and the Pacific Basin (U.S. Department of Agriculture Handbook 296). USDA-NRCS.

______. (2010). Field Indicators of Hydric Soils in the United States: A Guide for Identifying

and Delineating Hydric Soils (Version 7.0). L. M. Vasilas, G. W. Hurt & C. V. Noble (Eds.). USDA-NRCS, in cooperation with the National Technical Committee for Hydric Soils.

______. (2013). Field Indicators of Hydric Soils in the United States: A Guide for Identifying

and Delineating Hydric Soils (Version 7.0, Errata). L. M. Vasilas, G. W. Hurt & C. V. Noble (Eds.). Retrieved from USDA-NRCS website: http://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/use/hydric/

Van Houten, F. B. (1973). Origin of Red Beds: A Review – 1961-1972. Annual Review of Earth

and Planetary Sciences, 1, 39-61. Veneman, P. L. M., & Pickering, E. W. (1983). Salt Bridge for Field Redox Potential

Measurements. Communications in Soil Science and Plant Analysis, 14, 669-677. Vepraskas, M. J. (1999). Redoximorphic Features for Identifying Aquic Conditions (Technical

Bulletin 301). Raleigh, NC: North Carolina Agricultural Research Service. ______. (2001). Morphological Features of Seasonally Reduced Soils. In J. L. Richardson & M.

J. Vepraskas (Eds.), Wetland Soils: Genesis, Hydrology, Landscapes, and Classification (pp. 163-182). Boca Raton, FL: CRC Press.

Vepraskas, M. J., & Bouma, J. (1976). Model Experiments on Mottle Formation Simulating

Field Conditions. Geoderma, 15, 217-230. Vepraskas, M. J., & Faulkner, S. P. (2001). Redox Chemistry of Hydric Soils. In J. L.

Richardson & M. J. Vepraskas (Eds.), Wetland Soils: Genesis, Hydrology, Landscapes, and Classification (pp. 85-106). Boca Raton, FL: CRC Press.

Vepraskas, M. J., & Sprecher, S. W. (1997). Overview of Aquic Conditions and Hydric Soils. In

M. J. Vepraskas & S. W. Sprecher (Eds.), Aquic Conditions and Hydric Soils: The Problem Soils (SSSA Special Publication 50, pp. 1-22). Madison, WI: Soil Science Society of America.

89