HISTORICAL CHANGES IN THE GEOMORPHOLOGY OF THE OTTAWA RIVER (NW OHIO, U.S.A.) DUE TO URBANIZATION AND LAND CLEARANCE
Laura D. Webb
A Thesis
Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE
August 2010
Committee:
James E. Evans, Advisor
Sheila J. Roberts
Jeffrey Snyder ii
ABSTRACT
James E. Evans, Advisor
In northwestern Ohio, the impact of humans on natural systems extends back hundreds of
years as manifested by complete reorganization of fluvial systems. This study addressed historical changes in the geomorphology the Ottawa River using vibracores, trenches, textural and geochemical analyses, and 14C and blue light optically stimulated luminescence (blue OSL)
dating.
The total section thickness from trenching and vibracoring is approximately 4.5-m. The
oldest sediment in the cores is interbedded massive sands and silts >1.5-m thick. These deposits
represent a point bar succession that is likely post-glacial in origin. Overlying the sand is 75-cm
thick interval of peats and organic-rich carbonaceous muds interbedded with thin sand horizons.
Several 14C analyses from this interval have calibrated ages of 4889 +/- 178 YBP, 4731 +/- 306
YBP, and 4547 +/- 326 YBP. These deposits are interpreted as hydromorphic paleosols and
overbank flood deposits that formed following the rise of Lake Erie.
An interval 33-cm to 68-cm thick overlies the paleosols and consists of alternating
massive or cross-bedded sands interbedded with discontinuous silts. One blue OSL date from
these sands produced an age of 231 +/- 15 YBP, which approaches the age of land clearance in
northwest Ohio (early-1800s). This interval is interpreted as channel and channel margin
deposits.
Further up section, a cross-bedded sand layer, dated at -4 +/- 5 YBP and -9 +/- 5 YBP,
corresponds with a major flood that occurred in this region during 1959. Overlying this historic iii
flood layer are approximately 1.6-m of silty floodplain deposits that accumulated during a period
of rapid population growth and construction upstream of the study area. The implications are that the Ottawa River flowed through riparian wetlands and had low banks prior to land clearance, and that excessive sediment loads dating from the agricultural period and
suburbanization boom are responsible for 1.6-m of vertical floodplain aggradation.
Following this period, the landscape was re-vegetated thereby decreasing the sediment
discharge. As a result, the Ottawa River incised into previously stored sediment which produced
the existing stream morphology of an entrenched channel flowing between terrace-like 2.3-m tall
streambanks that are still inundated annually. iv
ACKNOWLEDGEMENTS
I would like to thank a number of people who made this work possible. First, I want to thank my advisor, Dr. Evans, for guiding me throughout my thesis work. I would not have made it this far without his instruction, patience, dedication, and incredible knowledge. I also want to thank Dr. Roberts and Dr. Farver for helping me with the geochemistry portions of this project.
Thank you to Shannon Mahan at the USGS Luminescence Lab for guiding me through the preparation process of my blue OSL samples. Thank you to the Ohio Geological Survey for allowing me to use their vibracorer. Thank you to the Geological Society of America, the
Geology Department at Bowling Green State University, the Graduate College at Bowling Green
State University, and the R.D. Hoare Graduate Student Research Fund for funding this project.
I would also like to thank Megan Castles, Will Emery, and Allan Adams for helping me collect vibracores. You really helped lighten the load. Even more so, I would like to thank
Megan Castles and Will Emery for encouraging me, studying with me, working with me, and making me laugh. I thank my family for their constant support, encouragement, and love. Every day, you inspire me to keep working hard.
Finally, I want to thank Erin Sullivan for keeping me focused, helping me with Adobe
Illustrator, constantly encouraging me, being incredibly understanding and patient, and loving me through the best and worst of it. I truly could not have done this without you. v
TABLE OF CONTENTS
Page
INTRODUCTION ……………………………………………………………………… 1
Human Impacts on Rivers………………………………………………………. 1
Sediment Budgets……….………………………………………………………. 3
Human-Induced Changes in Sediment Budgets………………………………… 4
Alluvial Stratigraphy as an Archive for Land Use Change…………………….. 9
BACKGROUND……………………………………………………………………….. 14
Study Area…………………………………………………………………...... 14
Geology………………………………………………………………………… 16
Historical Land Use Changes…………………………………………………... 23
Soils and Modern Hydrology…………………………………………………... 35
METHODS……………………………………………………………………………... 41
Field Work……………………………………………………………………… 41
Laboratory Work………………………………………………………………. 46
Sedimentation Rates……………………………………………………………. 56
Sediment Budget……………………………………………………………….. 56
RESULTS……………………………………………………………………………… 74
Lithofacies……………………………………………………………………… 74
Lithofacies Assemblages………………………………………………………. 86
Alluvial Stratigraphy…………………………………………………………… 94
Sedimentation Rates……………………………………………………………. 95
Geochemical Analysis………………………………………………………….. 102 vi
Sediment Budget……………………………………………………………….. 109
DISCUSSION………………………………………………………………………….. 114
Depositional Environments…………………………………………………….. 114
Significance of Paleosols………………………………………………………. 116
Alluvial Stratigraphy…………………………………………………………… 120
Alluvial Stratigraphy and Land Use Changes…………………………………. 122
Sediment Budget……………………………………………………………….. 125
CONCLUSIONS………………………………………………………………………. 130
REFERENCES………………………………………………………………………… 133
APPENDICES………………………………………………………………………… 139
APPENDIX A STRATIGRAPHIC SECTIONS……………………………………… 140
APPENDIX B GRAIN SIZE ANALYSIS……………………………………………. 152
APPENDIX C GEOCHRONOLOGY………………………………………………… 162
Blue OSL Age Dating………………………………………………………….. 163
Radiocarbon Age Dating……………………………………………………….. 165 vii
LIST OF FIGURES
Figure Page
1 Example of cut bank stratigraphy………………………………………. 10
2 Evolution of a floodplain in the Maryland Piedmont………………….. 13
3 Location map of the study area…………………………………………. 15
4 Bedrock stratigraphy of the study area…………………………………. 17
5 Evolution of glacial lakes in the Lake Erie Basin………………………. 20
6 Map of the extent of the Black Swamp in northwestern Ohio………….. 22
7 Agricultural land use in Lucas County and population data……………. 24
8a-c Population changes in NW Ohio………………………………………... 29-31
9 Number of new housing units in Sylvania, OH (1950-2000)…………… 34
10 Compilation of soil maps for three counties in the Ottawa River
Watershed………………………………………………………………. 36
11a Flood exceedance probability graph for the Ottawa River, Ohio……….. 38
11b Relationship between discharge and stage height in the Ottawa River…. 38
12 Suspended sediment discharge of the Ottawa River relative to
total water discharge…………………………………………………….. 40
13 Location of measurements made along the cores……………………….. 43
14 Core photographs……………………………………………………….. 76
15 Correlation diagram of seven stratigraphic sections that extend
below the water table……………………………………………………. 89
15a Key to symbols………………………………………………………….. 90
viii
16 Examples of the clastic floodplain facies assemblage superimposed
with the modern soil profile at four locations in the study area…………. 92
17 Correlation diagram with locations and depths of samples collected
for blue OSL and radiocarbon dating…………………………………… 93
18 Sedimentation rate diagram along with locations and depths of
blue OSL and radiocarbon samples and their corresponding ages……… 98
19 Sedimentation rates calculated from blue OSL ages OR-09-1 through
OR-09-3 at location 09OR-5……………………………………………. 99
20 Sedimentation rates calculated from blue OSL ages OR-09-4 through
OR-09-6 at location 09OR-6……………………………………………. 101
21 Location and depth of samples collected for ICP-OES analysis………... 104
22 Changes in the concentration of seven elements with depth
at location 09OR-5……………………………………………………… 105
23 Changes in the concentration of seven elements with depth
at location 09OR-6……………………………………………………… 107
24 Changes in the concentration of seven elements with depth
at location 09OR-12………………………………………………….… 108
25 Vertical distribution of median major and trace element
concentrations in the given soil horizons……………………………….. 118
26 Example of the anthropogenic terraces resulting from suburbanization
and lower elevation floodplain………………………………………….. 126
ix
LIST OF TABLES
Table Page
1 Lucas County agricultural land use…………………………………… 25
2 Lucas County population change……………………………………... 28
3 Changes in the number of housing units in Sylvania, OH……………. 33
4 Description of push cores and vibracores collected along the
Ottawa River………………………………………………………….. 42
5 Calculation of element concentrations in standards for ICP-OES
analysis………………………………………………………………. 55
6 Calculations of standards for ICP-OES analysis……………………… 57
7 Sedimentation rates calculated using blue OSL ages…………………. 58
8 Determination of volume of sediment in floodplain storage
since 1959 flood.……………………………………. ………………… 60
9a R factor calculations for the Ottawa River watershed………………. 62
9b K factors for Fulton, Lucas, and Monroe County……………………. 64
9c LS factors for Fulton and Lucas County……………………………… 65
9d USLE values for the Ottawa River watershed……………………….. 67
9e Conversion of USLE values to volumes……………………………… 69
10 Sediment yield calculations for the Ottawa River watershed………… 70
11a Sediment delivery ratios for the Ottawa River watershed……………. 71
11b Estimated sediment delivery ratio, sediment yield, and storage…………… 73
12a Lithofacies code for coarse-grained material…………………………. 75
12b Lithofacies code for fine-grained material……………………………. 81
13 Lithofacies assemblages………………………………………………. 87 x
14 Blue OSL ages and conversions to calendar years…………………… 96
15 Radiocarbon age dating sample information………………………… 97
16 Geochemical profiles at three locations………….…………………… 103
17 Geochemical profile from soils in Lithuania…………………………. 117
1
INTRODUCTION
Human Impacts on Rivers
Humans can impact fluvial systems in a number of ways. One type of interference relates to land clearance and cultivation (Trimble, 1983). When land is cleared and developed for agriculture, soil erosion and runoff increase. Bosch and Hewlett (1982) examined a number of experimental watershed studies and found that for every 10 percent loss of deciduous hardwood forest due to land clearance there was a 25-mm effective runoff increase in total annual water yield. A key concept in these studies is recognition of the “Agricultural period,” in other words, a historical interval of time of increased water runoff and stream sediment loading due to human- induced soil erosion from farming. The time interval of the Agricultural period varies geographically and is mostly dependent upon the timing of European Settlement. In the mid-
Atlantic region of the United States, this period began in the early-1700s (Jacobson and
Coleman, 1986; Walter and Merritts, 2008). Europeans moved westward and settled portions of eastern Ohio in the early-1800s (Evans et al., 2000) and portions of northwest Ohio in the mid-
1800s (Wilhelm, 1984).
Through the examination of seven streams in Maryland, Jacobson and Coleman (1986) calculated that peak soil erosion during the Agricultural period was 600% higher than during the
Pre-settlement period. In accordance with sediment budget concepts, when the sediment supply exceeds the river’s conveyance capacity, increases in intrabasinal storage (colluvium and alluvium) occur. 2
Urbanization can also impact large portions of watersheds due to sediment loading
resulting from construction of housing developments, increased runoff due to increased
impervious surfaces, and the straightening and simplifying runoff pathways. During the onset of
urbanization, an abundance of construction projects coincides with the clearing of land and
exposure of unconsolidated material. This process results in large but temporary increases in
both sediment supply and runoff (Leopold and Skibitzke, 1967; Hollis, 1975; Sauer et al., 1983;
Roberts and Pierce, 1974). In Maryland, Roberts and Pierce (1974) examined the Patuxent River
during a period of urbanization (1968-1969). They showed that discharge was consistent (95%)
with long-term averages despite slightly lower levels of precipitation (79% of the average), but
during 1968-1969 there was a 141% increase in suspended sediment discharge (from 143-t/km2
to 344-t/km2). They argued that the dramatic increase in suspended sediment could only be
attributed to urbanization by showing an example of an event where the suspended sediment
yield of an urbanized portion of the river peaked at 620-t/km2 while a rural portion of the river peaked at 290-t/km2. Between 1968 and 1969, it was estimated that 82% of the suspended
sediment discharged by the Patuxent River came from construction sites, even though these areas
only represented 23% of the drainage basin (Roberts and Pierce, 1974). The sediment-rich water
from construction areas is quickly channelized and delivered to the fluvial system via storm
sewer networks (Baker et al., 2004). There, the conveyance capacity of the river is quickly
exceeded and the amount of sediment in storage increases.
When construction ceases, the landscape becomes re-vegetated and soil erosion decreases
(Wolman and Schick, 1967). At the same time, runoff remains elevated above natural values
because the urbanized drainage system remains in place. This changing relationship of Q
(discharge) and QS (sediment discharge) allows for streams to pick up previously stored 3
sediment. As a result, the stream begins to entrench its banks and channel as it returns to a
lateral migration regime.
Sediment Budgets
In fluvial systems, the sediment budget is influenced by the relationship between input,
output, and storage (Evans et al., 2000; Allmendinger et al., 2007).
Input = Output +/- Δ Storage (Eqn. 1)
In this case, input consists of material from sources such as soil erosion, mass wasting, eolian
sand and dust, and glacial inputs (Jackson, 1997). Output, or sediment yield, includes the
volume of material transported out of the system via bedload, suspended load, and dissolved
load. The intrabasinal storage component is, therefore, comprised of the volume of material that
is deposited in the system long- or short-term. Common storage areas include alluvium
(floodplain sediment and dunes and bars in channels), colluvium (colluvial fans and gully and rill deposits), and reservoir sediments (Evans et al., 2000). Sediment conveyance refers to the
transport of sediment from an initial point to an exit point (Faulkner and McIntyre, 1996).
Output (sediment yield) and input (erosion) can also be compared using the sediment delivery
ratio (Lu et al., 2006).
When the rate of sediment input exceeds the rate of output in the long-term, there is a net
increase in storage (Trimble, 1983). Material is deposited in storage areas such as colluvial fans,
floodplains, or channel features such as dunes and bars. If the sediment input is less than the
output, there is a net decrease in storage. In this case, both channel incision and bank erosion
ensue. This is a dynamic relationship. For example, if the sediment input is equivalent to the 4 output in the long-term, both erosion and deposition will take place as the channel migrates laterally, with no net long-term change in storage.
Human-Induced Changes in Sediment Budgets
Agricultural Effects
One cause of excess sediment input is land clearance associated with agricultural development (e.g. Wolman, 1967; Costa, 1975; Jacobson and Coleman, 1986; Walter and
Merritts, 2008). The impact of agricultural activity on fluvial systems extended westward across
North America starting in the east coast in the early-1700’s (Jacobson and Coleman, 1986;
Walter and Merritts, 2008) and reaching the Midwest in the early- to mid-1800’s (Wilhelm,
1984). The effect of land clearance is to significantly increase soil erosion (increase in sediment loadings to channels) and increase runoff (increased input of water to channels).
A study of watersheds in the north central United States argued that the sediment concentration in runoff is proportional to the amount of cultivated land in the watershed (Brune,
1948). The study showed that on average, a drainage basin of 259-km2 (100-mi2) will have a sediment concentration in runoff equivalent to 0.015% by weight if one-third of the drainage basin is cultivated. The concentration increases 6.5 times if the basin is one-third to two-thirds cultivated and increases 35 times if the basin is more than two-thirds cultivated. Brune (1948) estimated the average sediment concentration in runoff in the Ohio and Great Lakes drainage basins to be 50 times higher than pre-disturbance basins. Relative to the sediment budget, this increase in sediment load corresponds with an increased input. 5
In response to an increased input, sediment yield and storage have also been shown to increase. With agricultural activity, additions to storage are caused by a greatly increased sediment supply, but only a marginally increased discharge (Jacobson and Coleman, 1986). The river is supplied with more sediment than it can transport, which results in deposition (Trimble,
1983). In floodplains, the aggradation can be extensive with many areas reporting 0.9- to 5-m of vertical accretion over approximately 200 years (Costa, 1975; Jacobson and Coleman, 1986;
Walter and Merritts, 2008). Floodplain sediment accumulated during the Agricultural period are termed “legacy” sediments (Allmendinger et al., 2007).
Increases in sediment yields can be equally impressive. Prior to settlement, most areas of the north-central and mid-Atlantic United States were dominated by forests. In the mid-Atlantic
Piedmont, Wolman (1967) reported sediment yields of 1.8- to 3.9-t/km2 year-1 for the forested watersheds of Broad Ford Run and Fishing Creek (MD), and estimated most forested watersheds to have sediment yields less than 35-t/km2 year-1. In the agricultural watershed of Gunpowder
Falls (MD) (1914-1943) however, the sediment yield was 283-t/km2 year-1. These findings illustrate that agricultural land use can increase sediment yields by up to two orders of magnitude.
Reduced Agriculture or Input Effects
Following these periods of agriculture, many studies have found marked decreases in sediment yields and sedimentation rates (Wolman, 1967; Costa, 1975; Jacobson and Coleman,
1986; Kuhnle et al., 1996; Walter and Merritts, 2008). In the Gunpowder Falls drainage basin
(MD), the sediment yield decreased from 283-t/km2 year-1 during the 1914-1943 interval of intensive farming to 82-t/km2 year-1 during the 1943-1961 interval when the land use shifted to 6 grazing and forest (Wolman, 1967). In seven other streams in Maryland, soil erosion rates were
600% higher during the Agricultural period than during the Pre-settlement period, but only 200% higher during the Very Recent period when agricultural land use decreased and soil conservation practices were implemented (Jacobson and Coleman, 1986). The decrease in erosion was attributed to both decreased acreage in farmland and the institution of soil conservation practices.
The response of the fluvial system to these new conditions was a shift from vertical accreting, avulsion-dominated streams to lateral migrating channels and the erosion of the channel bank and floodplain sediment in storage (Jacobson and Coleman, 1986).
In the Goodwin Creek Watershed of Mississippi, a distinct change in sediment load was found to be associated with decreased agricultural activity (Kuhnle et al., 1996). Over a 9-year period, annual surveys of land use throughout the watershed were conducted. The study calculated a 53.8% decrease in cultivated land (from 26% in 1982 to 12% in 1990) and a 21.6% increase in idle pasture land (from 48.2% in 1982 to 61.5% in 1990). This transition from agricultural to pasture land took place in areas with slopes steep enough to make farming impractical due to excessive erosion. Over this same time period, the study measured a decrease in fine sediment (<0.062-mm) yield at the outlet of the watershed. A positive correlation was found between the mean annual sediment fine sediment concentration and the percentage of land under cultivation. The cause of a lower concentration of fines was interpreted as both a decrease in sediment supply and a reduction in runoff. In summary, this study showed that a reduction in agricultural land corresponded with reduced runoff rates which caused a decrease in sediment erosion and transport (Kuhnle et al., 1996).
In the Piedmont province, another study found that sedimentation rates in the Western
Run watershed had declined three times following the same pattern of less farmland and the 7
implementation of soil conservation practices (Costa, 1975). The sediment load here remained
elevated however, due to stream incision and remobilization of previously stored sediment
(Costa, 1975). The source of sediment merely shifted from farm field runoff to streambank
erosion.
Changes in sediment loads were also linked to anthropogenic activity in agricultural
watersheds of Wisconsin (Faulkner and McIntyre, 1996). Here, the sediment loads were
expected to decrease following years of better soil conservation practices and abandonment of
cultivated land since the 1930s. However, as in Maryland and Virginia, the decrease in sediment
input from agricultural land was masked by sediment input due to streambank erosion. Thus, the
sediment yield maintained high levels despite soil conservation efforts (Faulkner and McIntyre,
1996).
Together, these studies illustrate that a decrease in agricultural land use corresponds with
a decrease in sediment supply (input). The fluvial system is no longer overwhelmed with
sediment, so aggradation ceases. The river then regains enough conveyance capacity to allow for erosion and transport of stored sediment (Costa, 1975; Jacobson and Coleman, 1986; Faulkner and McIntyre, 1996; Kuhnle et al., 1996). Thus, the sediment yield (output) may remain elevated even as storage decreases.
Urbanization Effects
Construction
Rather than merely seeing a decrease agricultural land, the institution of better land use
practices, or an increase forested land, many watersheds have experienced a period of
urbanization following agricultural land use (Wolman, 1967; Wolman and Schick, 1967; 8
Allmendinger et al., 2007). The process of urbanizing a watershed begins with housing
construction, and construction begins with land clearance. As opposed to agricultural land
clearance though, land clearance from construction makes a much greater impact over a much
shorter time.
When vegetation is removed, there is a period of rapid removal of the newly exposed soil
(Leopold, 1956). Associated sediment yields can be one to three orders of magnitude greater
than agricultural sediment yields (Wolman, 1967). Where agricultural yields range from several
tens to hundreds of tons/km2 year-1, annual sediment yields from construction areas can reach from several hundred to 55,000-t/km2 (Wolman and Schick, 1967; Allmendinger et al., 2007). In
terms of population growth, sediment yield was calculated to increase 700-1800 tons of sediment
per 1000 person increase in population (Wolman and Schick, 1967). These radically higher
sediment yields quickly exceed the conveyance capacity of most rivers and result in significant
increases in intrabasinal storage (Wolman, 1967; Wolman and Schick, 1967, Allmendinger et al.,
2007).
Post-Construction
Following construction, the landscape becomes re-vegetated or covered with impervious
surfaces or debris. As a result, the sediment supply is significantly reduced, and sediment yields
in these areas should notably decrease. Estimates place the sediment yields near pre-settlement
levels of approximately 10-t/km2 year-1 (Allmendinger et al., 2007). However, coinciding with the construction of impervious surfaces and storm sewer networks is also an increase in runoff
(Wolman, 1967). For example, peak runoff values were two to six times greater in areas following the emplacement of impervious surfaces (Carter, 1961), and peak discharges increased 9
1.3 to 7.7 times in Maryland (Beighley and Moglen, 2002; Palmer et al., 2002). The combination of increased runoff and decreased sediment yields results in an increased sediment conveyance capacity. Rivers are able to pick up sediment from their banks and channels thereby reducing storage.
Overall, urbanization is characterized by two phases. Initially, land clearance due to construction creates an excess supply of sediment. This sediment overloads most fluvial systems to the point of extensive deposition and aggradation. Following construction, the landscape is covered with vegetation and impervious surfaces which sever the sediment supply and increase the rapidity of runoff. Consequently, the rivers are capable of entraining additional sediment from storage, and return to a system of lateral migration.
These studies demonstrate the tremendous influence anthropogenic activity has on fluvial systems throughout the country. Sediment input, output, and storage can all be highly impacted by land use. The signature of these human-induced changes should be apparent in the floodplain stratigraphy of associated rivers.
Alluvial Stratigraphy as an Archive for Land Use Change
A number of studies have examined the alluvial stratigraphy of rivers exposed to land use changes in the eastern United States and noted strikingly similar characteristics (Costa, 1975;
Jacobson and Coleman, 1986; Walter and Merritts, 2008; Allmendinger et al., 2007). Studies indicate that pre-development rivers in this region were very different from their modern counterparts. As a result, a distinctive stratigraphy could be found as described below (Fig. 1).
10
Figure 1. Sample cut bank stratigraphy. The buried A horizon (Ab) denotes the floodplain surface during the Pre-settlement period (Jacobson and Coleman, 1986).
11
Several studies in Pennsylvania and Maryland found that the basal layer consists of coarse-grained channel deposits. According to a survey of 20 watersheds in these states, the lower stratigraphic profile contains quartz-rich gravel (Walter and Merritts, 2008). Another study of seven small streams in the Maryland Piedmont noted a similar layer of iron oxide- cemented gravel (Jacobson and Coleman, 1986). In Montgomery County, Maryland, the unit is described as angular coarse-grained sediment (Allmendinger et al., 2007). A study in the
Piedmont province details a coarse-grained deposit of clayey to sandy quartz gravel (Costa,
1975).
Above this layer is an organic-rich silt loam (Walter and Merritts, 2008). The carbonaceous layer is interpreted as a hydromorphic soil due to its high organic content and abundance of seeds, nuts, roots, algal mats, and pollen. This layer has 14C calibrated ages of
11,240 to 300 YBP, which are consistent with pre-settlement times. Other studies describe the unit as either an organic horizon (Allmendinger et al., 2007), a laminated gray to red-brown silt that may contain twigs, nuts, and pollen (Costa, 1975), or as a light-gray to yellow clay loam topped with a black to dark-gray A soil horizon (Jacobson and Coleman, 1986). The clay loam deposits were again interpreted to represent Pre-settlement soils. These dense, cohesive fine- grained soils also contain mottles and concretions indicative of water-saturated conditions
(Jacobson and Coleman, 1986).
The thick pale brown upper unit is a combination of sand, silt, and clay with a much lower organic content (Walter and Merritts, 2008; Allmendinger et al., 2007; Jacobson and
Coleman, 1986). It contains a number of human artifacts including cut planks and pieces of brick and coal (Walter and Merritts, 2008), junk dumps, oyster shells (Costa, 1975), bottles, cans, and textiles (Jacobson and Coleman, 1986). Such artifacts were only discovered 12
stratigraphically above the buried soil horizon. The use of 210Pb dates and pollen analysis
confirms that the accumulation of this material occurred post-1700 or following European
settlement (Walter and Merritts, 2008). These anthropogenic sediments are less dense and more
friable than the underlying deposits. In summary, the evidence is consistent that this upper layer
was deposited during the Agricultural period.
Overall, alluvial deposits in eastern North America consist of three layers and the ages of
these layers correspond to the timing of changes in land use in this region. The change from pre-
settlement wetlands and woodlands to cleared farmland in the Agricultural period caused distinct
changes in the morphology of the floodplains (Fig. 2). Pre-settlement conditions included lateral
channel migration with deposits dominated by coarse-grained channel sediment and organic-rich
clay and peat from riparian wetlands. During the Agricultural period, increased agricultural
activity resulted in an excessive sediment supply causing vertical floodplain aggradation and
avulsion dominated streams. Then, during the post-Agricultural period, better land use practices
and decreases in farming reduced the sediment supply. As a result, there was both vertical
incision and lateral bank erosion. This final phase of land use corresponded with reworking of the anthropogenic terraces and the establishment of a lower elevation floodplain. Because the
Ottawa River in northwestern Ohio experienced a similar history of land use changes, although at different historical times, a similar stratigraphic sequence and floodplain morphology was expected to be found.
13
Figure 2. The evolution of a floodplain in the Maryland Piedmont. “PS” represents Pre- settlement period material, “A” represents Agricultural period material, and “VR” represents Very Recent period material (Jacobson and Coleman, 1986). 14
BACKGROUND
Study Area
The Ottawa River is located in northwestern Ohio and southeastern Michigan (Fig. 3).
The low gradient, 446-km2 watershed feeds into Maumee Bay in the western portion of Lake
Erie (Roberts et al., 2007). A combination of land uses can be found in the watershed today
including agricultural, suburban, and urban. The Ottawa River is highly urbanized in its lower
reaches (up to RK 10), flows through residential and suburban areas in its middle reach (RK 10
to RK 39.5), and flows through primarily agricultural land in its upper reaches (> RK 39.5)
(Roberts et al., 2007; Mannik-Smith Group, Inc., 2008; Gerwin, 2003).
As part of an effort to improve the water quality of the Ottawa River by reducing Total
Maximum Daily Loads (TMDL’s), several low-head dams were removed. The final dam, the 2-
m tall Secor Dam (RK 18.3), was removed in November 2007 (Evans and Harris, 2008). Prior to
removal, the dam had a small reservoir that stretched 150-m upstream. The majority of the
accumulated sediment in the reservoir was remobilized within six weeks following the dam
removal and transported downstream (Evans and Harris, 2008). Along the banks, a more
resistant layer of peat was exposed near the level of the mean daily stage height (peat
interbedded with silty sand with abundant wood debris). The peat layer actually made a
nickpoint which slowed the rate of sediment erosion after the dam was removed.
The streambanks themselves lack many bank stabilization structures, and the river itself
has an atypical floodplain. The stream exists as an incised channel bordered by 2.3-m tall paired
terraces. Evans and Harris (2008) interpret the terraces as anthropogenic in origin. The 15
Figure 3. Location map of the study area (Modified from Roberts et al., 2007). The locations of push cores, vibracores, and trenches are numbered. The location of the former Secor Dam is also noted.
16 floodplain does experience periods of flooding, both historically (Toledo Blade, 1959) and today, as evidenced by USGS stream gage station data at the University of Toledo campus. Land use changes associated with human activity may be the cause of the drastic changes in sedimentation rates and the resulting morphology seen today.
Geology
Regional Geologic Setting
In northwest Ohio, the Findlay Arch is the dominant structural feature (Coogan, 1996).
The arch plunges to the northeast which allowed for the accumulation of sediment along the northwestern and southeastern flanks. Ordovician – Mississippian age sedimentary rocks dip northwestward into the Michigan Basin and southeastward into the Appalachian Basin (Coogan,
1996).
Bedrock Geology and Stratigraphy
In the Ottawa River watershed, the relatively flat topography is underlain by Silurian-
Devonian limestone and dolomite with minor siliciclastics (Norris, 1975). The river crosses stratigraphically down-section through six units beginning with the Antrim Shale in the upstream region, and moving into the Tenmile Creek Dolomite, the Silica Formation, the Dundee
Limestone, the Lucas Dolomite, and ending with the Tymochtee Dolomite (Harris, 2008; see
Fig. 4). The Tymochtee Dolomite specifically underlies the study area.
As the Taconic Highlands eroded in the eastern portion of North America, less clastic material reached Ohio during the early to middle Silurian Period (Camp, 2006). The result was a
17
Figure 4. Bedrock stratigraphy of the study area (Modified from Harris, 2008; Camp, 2006). Dotted line denotes the presence of an unconformity. 18
marked transition from siliciclastic deposits to carbonate deposits. A shallow sea covered the
area, and abundant reef complexes extended across northwestern Ohio and southwestward along
the Cincinnati Arch. The deposits from this time would later become the Lockport Dolomite.
Eventually, the sea began to recede. In the shallow sub-tidal areas, the deposits of the Greenfield
Dolomite accumulated. Evidence of continued subaerial exposure can be found in the overlying
Tymotchee Dolomite which contains abundant mud cracks and few fossils. Gypsum and
anhydrite are also present in areas where restricted water flow led to increased salinity and
precipitation. During the late Silurian to middle Devonian, the central part of the Michigan basin
deposited gypsum and carbonates that form the undifferentiated Salina Group. As a result of
subaerial exposure, a middle Devonian unconformity developed across the region (Camp, 2006).
Sea level rose again by the late to middle Devonian, which is recorded by the upward progression from clastic material (Sylvania Sandstone) to non-clastic (Amherstburg Dolomite).
The Dundee Limestone was deposited during these shallow marine conditions (Camp, 2006).
Additional fossiliferous shale and limestone accumulated in a similar environment (Silica
Formation and Tenmile Creek Dolomite), followed by a thick sequence of shale (Antrim Shale).
The presence of organic material, fine-grained siliciclastics, and tempestites supported the interpretation for the depositional environment of the Devonian shales as a muddy, anoxic, shallow marine setting (Coogan, 1996). Bedrock was subsequently covered by 31 to 43-m thick glacial deposits (Forsyth, 1968).
Glacial Geology and History
One of the pre-eminent influences on the Ottawa River watershed was the Late Cenozoic evolution of the Lake Erie basin. The complex history includes multiple glaciations, drainage 19 disruption, and periods of post-glacial isostatic rebound (Larson and Schaetzl, 2001). Multiple ancestral lake phases resulted from the final glacial advancement and retreat.
The evolutionary stages of Lake Erie unfolded over a 16,000 year period (Leverett and Taylor, 1915; Forsyth, 1968; Larson and Schaetzl, 2001). Glacial Lake Leverett was the initial lake phase that formed 16 Ka as the Wisconsin ice sheet advanced. Then, as the ice started to retreat, Glacial Lake Maumee formed. Leverett and Taylor (1915) subdivided this lake stage into three phases (Maumee I, II, and III) based on the shifting outlet location (Fig. 5). At
13.6 Ka, continued retreat of the ice sheet led to the formation of Glacial Lake Arkona as the
Huron and Erie Basins merged (Fig. 5). The lake expanded laterally, but exposed a lower outlet which dropped the lake level and created Glacial Lake Whittlesey (Forsyth, 1968). A similar process repeated, as the Wisconsin ice sheet retreated and allowed for the formation of Glacial
Lake Warren due to the union of the Huron and Erie Basins. A lower outlet once again decreased the lake level and, by doing so, established Glacial Lake Wayne (Fig. 5).
The present day outlet at the Niagara River was generated 11.8 Ka, and further diminished the water level (Forsyth, 1968). This development resulted in the first stage of the modern Lake Erie. However, only the deepest segments were submerged. With further ice sheet retreat, isostatic rebound caused both the outlet and lake level to rise. In western Lake Erie, the rise created estuaries in the streams emptying into Maumee Bay (Forsyth, 1968). The lake, as it is known today, was in place approximately 5 Ka (Camp, 2006).
Examination of soils in the Ottawa River watershed by Gallagher (1978) uncovered evidence of this complex glacial lake history. Sand ridges were found to be resting on glacial lacustrine silt and clay. Gallagher interpreted the ridges to represent previous shoreline locations
20
Figure 5 (A-H). The evolution of glacial lakes in the Lake Erie Basin between 16 and 5 Ka (From Larson and Schaetzl, 2001). (A) Glacial Lake Leverett. (B) Glacial Lake Maumee. (C) Glacial Lake Arkona. (D) Lake Ypsilanti. (E) Glacial Lake Whittlesey. (F) Glacial Lake Iroqouis. (G) Early Lake Erie. (H) Modern Lake Erie. 21
of ancestral Lake Erie. In other locations, such as Oak Openings, the wind reworked the sand
ridges into dunes (Camp, 2006).
Post-glacial History of the Ottawa River watershed
Prior to fairly recent agricultural development, northwest Ohio was dominated by a
region known as the Black Swamp (Fig. 6). The swamp developed gradually as the glacial ice
receded (Camp, 2006). When European settlers arrived, the region consisted of both wetlands
and woodlands covering an area of 195-km east-west and 65-km north-south (Black Swamp
Conservancy, 2009). Ash, basswood, elm, hickory, maple, and oak trees formed a thick canopy
over the wet areas, while oak and hickory filled the sand ridges (Camp, 2006). Along with
occasional bedrock outcrops, the sand ridges were the only dry ground. Due to drainage problems (Wilhelm, 1984) and human health threats such as cholera and malaria (Kinney, 1999), the Black Swamp was one of the last parts of Ohio to be settled. Before major settlement could take place, two key problems had to be addressed. The water table needed to be lowered and stagnant surface water needed to be drained (Wilhelm, 1984). To drain the surface water, open ditches were dug following the first ditch laws in 1859 passed by the Ohio General Assembly
(Camp, 2006). Underdrainage tile was also installed to lower the water table. By 1879 half of
the swamp was cleared of trees and by 1900 nearly all of the land was cleared and drained (Black
Swamp Conservancy, 2009). As a result, little of the Black Swamp remains today. For example,
less than 5% of Wood County today is still wetland forest, compared to more than 90% in 1830
(Kinney, 1999).
22
Figure 6. Map of the extent of the Black Swamp in northwestern Ohio. It exists where flat land and fine-grained lacustrine clay prevented adequate natural drainage. Star denotes the location of the study area (Forsyth, 1960). 23
Historical Land Use Changes
Early Industrial and Agricultural Development (1870-1940)
Through the use of fertilizer and crop rotation within the newly aerated soil, the Black
Swamp region became some of the most productive farmland in the world (Wilhelm, 1984).
Between 1880 and 1900, agricultural land use in Lucas County increased 69.2% from 98,798 acres to 167,133 acres (Fig. 7 and Table 1). Grain and livestock farming were abundant during this period (Toledo Regional Area Plan for Action, 1970). In the city of Toledo, manufacturing also made a major upturn between 1870 and 1900. The city’s population increased dramatically from 31,600 to 131,800 (U.S. Census of Population, 1950). The increase was the result of employment opportunities in the manufacturing industry at companies such as the Milburn
Wagon Company, which moved into the city in 1873. The number of these industries with production values in excess of one million dollars per year grew from two to eight. Four petroleum refineries were also constructed during this time, which would be well developed by the late-1930’s (Toledo Regional Area Plan for Action, 1970).
By 1939, the glass industry also had a major foothold in the city, and employed 10% of local manufacturing workers (Toledo Regional Area Plan for Action, 1970). The home offices of four of the nation’s leading glass corporations were located in the Toledo area. The automobile industry became important to the area as well during the 1910’s. By 1931, the automotive industry employed more than one-fourth of local manufacturing workers. Iron and metal products were also fabricated in the region. Following the Great Depression though, the automotive industry never regained its original position in the local economy (Toledo Regional
Area Plan for Action, 1970). 24
Figure 7. Agricultural land use in Lucas County as measured in acres of land in farms (U.S. Census of Agriculture, 1880-1997). Also reported are population data for Sylvania Township, Ohio and the city of Sylvania, Ohio (U.S. Census, 1890-2000). 25
Table 1. Lucas County Agricultural Land Use. Land in farmsa Percent Year (thousands of acres) Changeb 2007 62.9 -19.2 2002 77.8 -2.2 1997 79.6 7.5 1992 74.0 -11.0 1987 83.2 -5.3 1982 87.9 -3.4 1978 91.0 -7.5 1974 98.3 -0.2 1969 98.5 -5.5 1964 104.3 3.4 1959 100.9 -16.6 1954 121.0 -0.2 1950 121.3 -8.6 1945 132.7 8.6 1940 122.3 -9.6 1935 135.2 12.5 1930 120.2 -21.3 1920 152.8 -7.7 1910 165.5 -1.0 1900 167.1 25.8 1890 132.9 34.5 1880 98.8 -- aLand in farms data was compiled from U.S Census data between 1880 and 1940, and U.S. Agricultral Census data from 1945 to 2007. b Calculated as: (|year1 - year2|/year2)*100, where year1 is the land in farms for a given year, and year2 is the land in farms for the previous year.
26
By 1920, the majority of the population was still centered in and around Toledo (Toledo
Regional Area Plan for Action, 1970). The reason for this centralization was a lack of mobility.
The primary sources of transportation were streetcars and buses. As a result, people had to remain within a reasonable distance from work and shopping, which was aided by the construction of high rise apartments and tall office buildings (Toledo Regional Area Plan for
Action, 1970).
Early suburbanization (1920-1940)
While suburbia is generally regarded as a post-World War II development, its roots can be traced to the 1920’s with the advent of the automobile (Toledo Regional Area Plan for Action,
1970). In 1920, the number of registered automobiles in Lucas County totaled 20,000. By 1940, that number had grown to over 100,000. Not surprisingly, a number of Toledo suburbs saw major growth during this period (Fig. 7). For instance, the population of Washington and Adams
Townships, adjacent to Toledo, doubled between 1920 and 1930. During this decade, the population of Perrysburg, Maumee, and Sylvania also grew by 50 to 100 percent. The village of
Ottawa Hills was established as well, and quickly gained 1185 residents by 1930. However, the suburbanization movement slowed dramatically during the depression (Toledo Regional Area
Plan for Action, 1970). To help stimulate residential development, the government approved a home mortgage insurance program (Toledo Regional Area Plan for Action, 1970). The program was soon followed by a housing boom and the purchasing of large portions of land for the mass construction of new housing.
27
Depression and Post-Depression Periods
The Toledo area was hit especially hard by the Great Depression (Toledo Regional Area
Plan for Action, 1970). Between 1927 and 1928, the two years prior to the crash, Toledo recorded a 29.8% increase in manufacturing wage earners. This increase exceeded that of any of the 33 other industrial centers in the country. Following the crash, from 1929 to 1931, Toledo also saw the greatest decrease (40.8%). Manufacturing jobs nationwide decreased 33% between
1929 and 1933. In Toledo, the number reached 51%. Retail sales were also hard hit.
Nationwide sales decreased 48%, while in Toledo, sales decreased 57%. As a result of the depression, companies began to decentralize and either branch out or move elsewhere (Toledo
Regional Area Plan for Action, 1970).
World War II
The war noticeably boosted the Toledo economy (Toledo Regional Area Plan for Action,
1970). Positions in manufacturing doubled, along with a significant increase in transportation employment. Many who worked during this period left following the war, but were replaced by returning veterans. The economy was now more diversified than it had been in the 1920’s.
Suburbanization (1950 – 1980)
Between 1959 and 1980, major population increases occurred upstream of the study area in the main suburban areas of Ottawa Hills, Sylvania Township, and the city of Sylvania (Table 2 and Figs. 8a, 8b, and 8c). For example, the population of Sylvania Township and the city of
Sylvania doubled every decade between 1950 and 1970. This was also the period when the greatest 28
Table 2. Lucas County Population Change. City of Sylvania Sylvania Twp Ottawa Hills (thousands of (thousands of (thousands of Year people) people) people) 2000 18.7 44.3 4.6 1990 17.3 40.0 4.5 1980 15.5 33.1 4.1 1970 12.0 28.6 4.3 1960 5.2 20.3 3.9 1950 2.4 12.1 2.3 1940 2.2 8.4 2.0 1930 2.1 6.4 1.2 1920 1.2 3.1 -- 1910 1.0 2.2 -- 1900 0.6 1.9 -- 1890 0.5 1.5 -- Source: U.S. Census, 1890 - 2000.
29
Figure 8a. Historical population changes in Ottawa Hills, OH between 1930-2000. The graph includes all years when a census of the population was gathered (Source: U.S. Census, 1930 – 2000).
30
Figure 8b. Historical population changes in Sylvania, OH between 1890-2000 (Source: U.S. Census, 1890-2000).
31
Figure 8c. Historical population changes in Sylvania Township, OH between 1890-2000 (Source: U.S. Census, 1890-2000). 32
number of new residents moved into the area (Table 2). The increase in population likely
corresponds with the development of business, shopping, entertainment, employment, and
housing in these areas (Toledo Regional Area Plan for Action, 1970). New housing developments were comprised mostly of single family homes in subdivisions which included larger lots in lower densities. Just north of Toledo, in Monroe County, a total of 1,010 new houses were built in these subdivisions in 1959 alone (Toledo Blade, 1960). Developers estimated that 75 to 98% of the homes were sold to people employed in the city of Toledo. Not surprisingly, a Toledo bank had $1 million invested in one such subdivision (Toledo Blade,
1960). In the city of Sylvania, the number of housing units more than doubled every decade from1950 to 1970 (Table 3 and Fig. 9). Between 1950 and 1980, this number rose from 738 to over 5500, which corresponds to an average of 162 new homes each year. Additional construction at the time consisted of a system of roads and freeways, including the Ohio
Turnpike, to meet the demands of automobile transit (Toledo Regional Area Plan for Action,
1970). Overall, the 1950s – 1970s consisted of abundant population growth and new construction in the suburban areas upstream of the study area.
Very Recent (Post – 1980)
Following this period, suburban population growth and new construction declined. In
Ottawa Hills, the city of Sylvania, and Sylvania Township, population growth decreased an average of 38% (Table 2, Figs. 8a, 8b, and 8c). These suburbs averaged 400 new residents per year between 1950 and 1980, but only 248 new residents per year between 1980 and 2000 (Table
2). Along with this slower rate of population growth was a slower rate of new construction. In the city of Sylvania, the construction of new homes peaked in 1980, then decreased sharply in 33
Table 3. Changes in the Number of Housing Units in Sylvania, OH. Total No. of New Housing Year Housing Units Units Percent Change 2000 7392 645 9.56 1990 6747 1164 20.85 1980 5583 2120 61.22 1970 3463 1845 114.03 1960 1618 880 119.24 1950 738 -- -- Source: U.S. Census, 1950-2000
34
Fig. 9. The number of new housing units in the city of Sylvania, OH from 1950-2000 (U.S. Census, 1950-2000). The point at 1960 would therefore represent the construction of 880 new housing units between 1950 and 1960 (Table 2).
35
the 1980s and into the 1990s (Table 3 and Fig. 9). The percentage of new homes each decade
dropped from an average of +98% between 1950 and 1980, to an average of +15% between 1980
and 2000 (Table 3). The average number of new homes being built each year dropped 54% from
162 (1950 – 1980) to 74 (1980 – 2000) (Table 3). Thus, this period can be characterized by
decreased rates of both construction and population growth.
Soils and Modern Hydrology
Soils
A number of distinct soils exist in the watershed. All soils are found on level to gently
sloping topography and are very poorly to somewhat poorly drained. The soil textures vary
widely, including clay, silt, or sand, and different types of loams. Soils in the upper drainage
basin formed on loamy to sandy beach ridges, glacial till, ground moraines, and outwash plains.
The Granby-Ottokee-Tedrow association formed on beach ridges and stretches across a large
portion of Lucas County and a small portion of Fulton County (Fig. 10). Soils that formed on
glacial till include the Hoytville-Nappanee-Mermill association and the Hoytville-Blount
association. A number of loamy to sandy soils formed on ground moraines and outwash plains
including the Pewamo-Selfridge-Blount association, the Haskins-Blount-Oshtemo association,
and the Mermill-Haskins association.
In the lower portion of the drainage basin, the soils formed on clayey and loamy
lacustrine and deltaic sediments (Fig. 10). The Del Rey-Lenawee association developed on this material and consists of loamy and clayey soil. The Bixler-Dixboro association, Colwood-Bixler association, and Mermill-Metamora-Haskins association also formed on glacial lake sediments, 36
37
but are composed of loamy and sandy soil. The Urban land association is found in this region as
well, but is dominated by anthropogenically modified soil in level and nearly level urban areas.
Modern Hydrology
A USGS stream gage station (#0417700) is in place along the Ottawa River at RK 17.3
(Harris, 2008). The record of data between 1975 and 2007 allowed for the calculation of flood
recurrence intervals. The intervals for the ten, twenty-five, fifty, and one hundred year floods
were determined to be 91, 127, 170, and 219 m3/s (3214, 4485, 6003, and 7734 cfs) (Harris,
2008). The graphs used to calculate these intervals can be found in Fig. 11a. The rating curve
for the Ottawa River shows an exponential relationship between discharge and stage height (Fig.
11b). The discharge has been depicted as flashy because during concentrated rain events, the
Ottawa River makes a dramatic shift from base flow to peak flow (Harris, 2008). A regional study in northwest Ohio and adjacent areas suggests land use changes were the cause of such flashiness (Baker et al., 2004). The study examined 515 Midwestern streams over a 27-year period to determine their flashiness index. “Flashy” discharge refers to the duration and frequency of short term adjustments in streamflow. In watersheds such as the Ottawa River, increased flashiness could be due to increased agricultural land in crop production, the related construction of ditches, and the related channelization of tributaries for the purpose of rapid conveyance of runoff (Baker et al., 2004).
The only detailed hydrologic studies of the Ottawa River was a 2-year (1975-1977)
investigation of discharge and sediment load by Gallagher (1978) and the 2-year (2006-2007)
study of the Secor Dam removal by Harris (2007). Gallagher measured suspended sediment load 38
Figure 11. (a) Flood exceedance probability graph for the Ottawa River, Ohio (modified from Harris, 2008). (b) The relationship between discharge and stage height in the Ottawa River. A gap exists in data collection between 1977 and 1990 (modified from Harris, 2008). 39
with a USDH-59 water sampler following standard USGS techniques (Guy and Norman, 1970).
The sediment concentration between May 1975 and November 1977 was measured in milligrams
of sediment per liter of water, and was converted to sediment discharge according to Eqn. 2.
QS = <ЄS>Q (Eqn. 2)
where QS is the sediment discharge, <ЄS> is the average sediment concentration, and Q is the total fluid discharge. The data for Q was gathered from the USGS gauging station at the Stadium
Road Bridge where the Ottawa River flows through the University of Toledo campus. A suspended sediment discharge curve was then constructed (Fig. 12). The amount of bedload was estimated using the methods described by Anttila and Tobin (1976). This approach uses a combination of data including suspended sediment load and texture along with channel substrate.
By doing so, Gallagher (1978) estimated 10 to 35 percent of the total sediment discharge could be accounted for as bedload transport.
Harris (2007) measured the bedload of the Ottawa River as part of studying the effects of removal of the Secor Dam. Prior to the dam removal, 11 bedload measurements downstream of the dam indicated bedload transport was negligible. For the week following the dam removal, 10 upstream and 6 downstream measurements indicated a significant amount of sediment was mobilized. However, during the ensuing weeks, the amount of bedload being transported decreased considerably (Harris, 2007).
40
Figure 12. Suspended sediment discharge of the Ottawa River relative to total water discharge. Data was collected from March 1976 through December 1977 (Modified from Gallagher, 1978).
41
METHODS
Field Work
A combination of trenches, push cores, and vibracores were used to examine the channel and floodplain stratigraphy at 11 locations (Fig. 3). Six vibracores and five push cores were collected and three trenches were dug (Table 4 and Fig. 13). Individual beds were observed in cores or trenches and were evaluated for composition, color, texture, and sedimentary structures.
Trenches were dug to the level of the water table and then a push core was collected to extend the trench down below the water table. Four samples were collected for 14C dating and six
samples were collected for blue OSL dating.
Vibracoring
Six vibracores were collected in an attempt to examine the stratigraphy laterally into the floodplain and at depths below the modern channel. For this study, the vibracorer was supplied by the Ohio Geological Survey – Lake Erie Section. The vibracorer consists of a flexible cable with a vibrating head at one end and a 4-cycle gasoline engine at the other end (Clark, 2008).
The top of a 7.5-cm diameter aluminum irrigation pipe was attached to the vibrating head and filed at the bottom to allow for faster and easier ground penetration. The pipe was stood up at the desired location and the engine was turned on. The vibracorer then began to vibrate at a rate
of 10,000 vibrations per minute and the pipe penetrated vertically into the sediments (Clark,
2008). The design of the vibracorer is based on the principle of liquefaction whereby saturated
42
Table 4: Description of Push Cores and Vibracores Collected Along the Ottawa River. a b c d e f g h Core No. CT dT dML1 di dS dML2 Comp. (%) Location 0281612mE, 09OR-1 V 114 11 28 86 103 16.5 4615214mN 0281609mE, 09OR-2 V 177 17 57 120 160 25.0 4615208mN 0281592mE, 09OR-3 V 189 13.5 71 118 175.5 32.8 4615230mN 0281554mE, 09OR-4 V 141.5 12 29 112.5 129.5 13.1 4615228mN 0281615mE, 09OR-5 P 92.5 35 39 53.5 57.5 7.0 4615220mN 0281622mE, 09OR-6 P 91 9 60.5 30.5 82 62.8 4615219mN 0281625mE, 09OR-7 P 50.5 9 20 30.5 41.5 26.5 4615213mN 0281437mE, 09OR-8 P 51.5 5 11.5 40 46.5 14.0 4615348mN 0281575mE, 09OR-10 V 371 51 139 232 320 27.5 4615248mN 0281595mE, 09OR-11 V 334.2 59.5 123.5 210.7 274.7 23.3 4615246mN 0281205mE, 09OR-12 P 51 -- 26 25 -- -- 4615564mN aCore type, V = vibracore, P = push core. bTotal length of aluminum irrigation pipe. cLength from top of pipe to mud line (marks the surface level on the aluminum irrigation pipe before pulling it out of the ground). dLength from the top of the pipe to the top of the sediment, as measured from inside the pipe. e Length of compacted sediment in aluminum irrigation pipe. Calculated as dT - di. f Length from mud line to bottom of the pipe. Calculated as dT - dML1. g Compaction, measured as [(dML2-dS)/dML2]*100 hCoordinates are in UTM.
43
Figure 13. Location of measurements made along the cores. Consult Table 4 for further descriptions. 44
material temporarily loses its strength and assumes properties similar to a fluid when vibrated
(Power and Holzer, 1996). This process occurs naturally during earthquakes, but can be
mimicked by the action of the vibracorer. As a result, the pipe was able to penetrate through
most sediment, unless it was blocked by gravel clasts, highly cohesive sediment, or bedrock.
Core penetration ranged from 103-cm to 320-cm (Table 4).
After the core has reached maximum penetration, the engine is turned off and the surface
level is marked on the outside of the pipe to allow for compaction calculations (Table 4). This
line is also known as a mud line. The pipe is then attached to a chain hoist on a steel tripod
(Clark, 2008). The top of the pipe is capped and the pipe is extracted. Once removed, the base of the pipe is also capped to inhibit sediment loss and drying out of the core. Any excess pipe at the top of the core is removed with a hacksaw. The pipe is then numbered and an arrow is marked on it for orientation purposes (Clark, 2008).
Push Cores
Five push cores were collected in a similar manner to the vibracores. In this case however, the tubes were inserted into the ground manually. Either a 7.5-cm diameter aluminum
irrigation pipe or a 4.5-cm diameter plastic pipe was used. Once the tube was inserted, the mud
line was drawn and the tube was removed. It was then numbered, oriented, and capped prior to
lab analysis. Push core penetration ranged from 41.5-cm to 82-cm (Table 4).
Trenches
Three trenches were dug into the streambanks using shovels and picks. The trenches
were approximately 0.5-m to 1-m wide and extended from the water table up to the ground 45
surface. After clearing the exposure, a stratigraphic section was measured in the field, and
samples were collected for grain size analysis 14C dating and blue OSL dating. In addition, several historical artifacts, including a bottle, a piece of tile, and a piece of rubber, were collected from exposed layers in the trenches.
Collection Methods for OSL samples
To collect the blue OSL samples, key horizons of sediment were selected. A 4.8-cm x
20-cm opaque metal pipe was capped on one end and laterally inserted into the horizon with a
rubber mallet. It is assumed that the last 2-cm to 3-cm of material on either end of the pipe will
be exposed to sunlight. Therefore, this length of pipe was selected to allow for a large enough
sample size to complete the analysis. The pipe was inserted until flush with the surface of the
exposure. Approximately 500-cm3 of sediment was collected in an air-tight bag from the same horizon as the pipe. This sediment was later used to determine the environmental dose rate.
The pipe was then twisted and removed with the open end pointed up to avoid any
sediment loss. If the pipe was not filled completely, more sediment from the same horizon of
material was added to prevent mixing of the sample. The pipe was then dried off and the ends
were sealed with duct tape. Labels were written on the pipe and dose rate sample, and the depth
and GPS coordinates of the sample were also noted to assist with environmental dose rate
calculations.
46
Laboratory Work
Core Stratigraphy
The collected vibracores were then analyzed in the BGSU Sedimentary Core Laboratory.
To do so, the cores were cut in half lengthwise using either a hacksaw or metal cutter. The halves of each core were labeled as either working half or archive half. The archive half was wrapped with plastic wrap and sealed in a plastic bag for future use. The working half was cleaned, photographed, logged (lithology, sedimentary structures, and contact relationships were described) and sampled. The color of each layer was determined while it was damp using the
Munsell soil color chart. A stratigraphic section was then created for each core using Adobe
Illustrator CS4 (Appendix A). The sections were used to identify and interpret lithofacies and correlate layers across the study area. Correlation lines were based on lithofacies and age relationships.
Grain Size Analysis
The grain size distribution of five samples was determined using sieves and a laser
particle analyzer. Initially, 100-g to 200-g of sediment were placed in beakers, weighed, and
oven dried over night. The samples were then re-weighed. The difference between the wet and
dry weight was used to determine the percent porosity. The sandy samples, 09LW-4 and 09LW-
8, were then powdered with a mortar and pestle to break up any clumps and placed in a stack of
-1 φ to +4 φ sized sieves. The sieves were agitated in a Rotap sieve shaker for a minimum of 15 minutes. The stack was then removed and the amount of sediment in each sieve was determined. 47
The clay and silt sized particles collected in the basal tray were placed in a beaker for further
examination on a laser particle analyzer.
Three other samples needed their organic content removed prior to grain size analysis.
To eliminate this material, samples 09LW-9, 09LW-14, and 09LW-15 were rinsed multiple times with 3% H2O2 and distilled water. After the reactions ceased, the samples were oven dried
over night and re-weighed to determine the amount of organic material. These samples were
then powdered with a mortar and pestle and wet sieved using a +4 φ sieve, basal tray, and
distilled water. The sand sized portion was placed in a beaker and oven dried for 24 hours. The
clay-sized and silt-sized portions were placed in a separate beaker and oven dried for 48 hours.
After drying, each beaker was weighed to determine the amount present. The sand-sized portion
was then dry sieved and any remaining silt and clay was added to the clay and silt beaker.
A Spectrex PC-2300 laser particle analyzer was then used to determine the amount of
clay and silt present in each sample. To dilute the samples, 0.1-g of sediment was placed in a
100-mL container with 10-mL of dispersant (to prevent flocculation) and 90-mL of distilled
water. A magnetic stirring rod was placed in each container which was then sealed with a lid
and vigorously agitated for several minutes to insure dispersion. The sample was immediately
placed in a laser particle analyzer to determine the grain size distribution of > +4 φ fraction.
The amount and percent of each grain size were then recorded and cumulative weight
percents were graphed vs. phi size to examine the skewness and grain size distribution visually
(Appendix B). The grain sizes were also grouped into percentages of sand, silt, and clay to allow
for description using a soil texture diagram (Fig. B-1).
48
Blue Light Optically Stimulated Luminescence (OSL) Dating
Optically stimulated luminescence (OSL) is luminescence produced by an irradiated
sample when it is stimulated by photons (Bøtter-Jensen et al., 2003). Blue light optically
stimulated luminescence (blue OSL) is a specific type of OSL which uses blue light to stimulate
quartz grains. These grains are exposed to radiation from both cosmic rays and radioactive
isotopes (e.g. U, Th, and K) decaying in the sample and surrounding environment (Li et al.,
2008). When irradiated, valence electrons become ionized and localize around crystal defects
(Bøtter-Jensen et al., 2003). If exposed to light, these electrons are freed from the defects and
luminescence is emitted. The intensity of the luminescence is proportional to the length of time
the sample has been buried prior to being exposed to sunlight (Rittenour, 2008). As a result, blue
OSL can be used to determine the time elapsed since sediment burial.
The age of a sample is obtained by dividing the equivalent dose (De) by the dose rate (DT)
(Rittenour, 2008).
Age = De/DT (Eqn. 3)
The equivalent dose is the amount of radiation absorbed by the sample following deposition
(measured as Grays). The dose rate is the amount of radiation energy absorbed per kilogram of
matter per unit time measured as Grays Ka-1(Lian, 2007). The concentration of radioactive elements in the sample and surrounding material is used as an estimate of the dose rate (Li et al.,
2008).
For this study, quartz sand was collected from six samples using standard procedures for luminescence dating as previously described. In the lab, the pretreatment began under sodium vapor lights. These low-wavelength monochromatic (589 nm) lights provide enough visibility for the human eye but prevent artificial bleaching. With each 20-cm pipe, approximately 2-cm 49
to 3-cm of material at each end was discarded and the middle 12- to 15-cm of material was placed in a beaker. To remove carbonates, 150-mL of 4N HCl was added to the beaker and left
to sit for 45-60 minutes. The stagnant HCl was then drained and the samples were rinsed twice with 800-mL of deionized water. Next, 100-mL of 35-50% H2O2 was added to remove organics.
After one hour, another 100-mL of H2O2 was added and the solution was allowed to sit
overnight. The samples were then soaked with 800-mL of deionized water for 2 hours. The
water was decanted and this rinsing process was repeated. Next, 100-mL of Na pyrophosphate was stirred in as a deflocculant and allowed to sit for 2 hours. The contents of each beaker were wet sieved using +2 φ, +2.5 φ, +2.75 φ, +3 φ, and +3.5 sieves. The sand fraction from each sieve was placed in a separate beaker, and the remaining silt and clay was placed in a graduated cylinder.
Heavy liquids were used to separate the quartz. Feldspars were separated from quartz by adding the samples to a Li Na tungstate mixture with a density of 2.57 g/cm3. The sample was
placed in a test tube and spun in a centrifuge until the denser grains had settled. The feldspar
was removed by freezing the bottom of each test tube with liquid nitrogen, then decanting the
floating K-feldspar grains.
A second heavy liquid treatment involved a heavy liquid with a density of 2.65 g/cm3.
The bottom of each test tube was again frozen, and the quartz grains, which now floated to the
top, were poured and rinsed on a filter. Then, the samples were placed in beakers and etched in
45-50% HF for 40 minutes followed by a 5 minute bath in 4N HCl. The etching removes surface
impurities and the alpha radiated layer. Once dried, the sand grains in each sample were adhered
to 1-cm aluminum disks and analyzed using the Riso TL/OSL-DA-15A/B luminescence reader according to the procedures described by Murray and Wintle (2000). With blue OSL, the 50
luminescence reader uses blue light-emitting diodes (LEDs) to emit photons of a specific
wavelength onto the sample disk (Lian, 2007). The sample reacts by emitting photons of a
shorter wavelength (the OSL) which are directed to a detector known as a photomultiplier tube.
The intensity of the OSL is then used to calculate the age of the sample (Appendix C).
14C Dating
The Earth is subjected to a constant influx of cosmic rays in the form of atomic nuclei
moving through space (Dickin, 1995). These particles possess incredible amounts of energy on
the order of 102 GeV (Attendorn and Bowen, 1997). When collided with atmospheric molecules,
cosmic rays generate neutrons (Dickin, 1995). The neutrons react with other atoms in the
atmosphere and produce radioactive nuclei. These cosmogenic nuclides can be used as tools for
dating (Dickin, 1995). The radionuclides with long enough half-lives for geologic use include
3H, 10Be, 14C, 26Al, 32Si, 36Cl, 39Ar, and 81Kr (Attendorn and Bowen, 1997).
Of these, 14C, or radiocarbon, is produced in the stratosphere via the reaction of cosmic-
ray neutrons with stable 14N (Faure, 1977):
14N + n 14C + p (Eqn. 4)
In this reaction, n is the energetic neutron and p is the emitted proton. The radiocarbon product
14 is quickly oxidized to form CO2 (Faure and Mensing, 2005). Eventually, these molecules are
either exchanged with the CO2 in water to be later deposited as carbonate or photosynthetically
absorbed by plants (Dickin, 1995). As a result, all living plants and the animals that feed on
them contain 14C which is at equilibrium with the 14C in the atmosphere (Faure and Mensing,
2005). The absorption of radiocarbon ceases when the plant dies, and the activity of the 14C 51
begins to decrease (Faure, 1977). Radiocarbon then decays back to 14N by negatron decay
(Dickin, 1995).
14C 14N + β- (Eqn. 5)
To date a sample of carbon that is no longer at equilibrium with the atmosphere, the
following equation can be solved for t using the half-life of 5730 +/- 40a (Attendorn and Bowen,
1997):
3 t = 19.035 x 10 log10(A0/A) (Eqn. 6)
14 14 where A0 is the C activity present when the organism was alive and A is the measured C
activity. Another, less commonly employed, half-life of 5568 +/- 30a may be substituted
(Dickin, 1995). This half-life was calculated by Libby (1955) based on the weighted average of
5580 +/- 45a, 5589 +/- 75a, and 5513 +/- 165a. The weighting itself was calculated by taking the
inverse square root of the error. These three ages were obtained using a mass spectrometer and
measured using gas counting with CO2 (Libby, 1955). At the time, Libby concluded that this approach yielded the most precise results. To date a sample with the Libby half-life, the following equation can be used (Faure and Mensing, 2005):
-4 t = (lnA0 – lnA)/[1.244x10 ] (Eqn. 7)
Using either Eqn. 6 or Eqn. 7, it is necessary to correct for variations in the concentration of
atmospheric 14C over time through calibration.
In this study, four radiocarbon dates were obtained from three distinct layers of material.
Approximately 10-g to 30-g of wood were collected for each sample and sent to Geochron
Laboratories for conventional 14C dating. There, the samples were cleaned, split into pieces, and
placed in an Acid-Alkali-Acid treatment (see below) to eliminate post-mortem contamination
(Dickin, 1995). The treatment involves an initial leaching of the samples with 4% HCl at 80°C 52 for 24 hours to eliminate any carbonates. Then, to remove humic acids and other organic contaminants, 0.1N dilute NaOH was added at up to 80°C for at least 24 hours. Finally, a second rinse of HCl is done to remove any atmospheric CO2 absorbed during the previous step (Dickin,
1995). The samples were then washed and dried prior to combustion and recovery of the CO2 for analysis. A gas proportional counter was used with a modern standard of 95% of the activity of NBS Oxalic Acid. The ages obtained are based on the Libby half life of 5570a. The ages were then calibrated to calendar years (cal BP) using a calibration program (Appendix C).
Geochemical Analysis
In order to determine if key layers of material are buried soils, their geochemistry was examined for changes in the vertical distribution of seven elements. A total of 10 samples from three different locations were collected to analyze on an inductively coupled plasma optical emission spectrometer (ICP-OES). The concentrations of two major elements, Mg and Na, and five trace elements Cu, Mn, Pb, Sr, and Zn were evaluated. These elements were chosen based on work done on 53 soil profiles throughout the country of Lithuania (Gregorauskiene and
Kadunas, 2006). Their study documented the vertical distribution of six major elements and 28 trace elements in a variety of soil textures using an inductively coupled plasma mass spectrometer (ICP-MS). The soils in that area all developed on Quaternary glacial deposits similar to those found in the Ottawa River watershed, including sandy loams, sand, gravel, and glaciolacustrine sand and clay (Gregorauskiene and Kadunas, 2006).
Prior to the analysis, the samples were prepared according to the sediment digestion protocol outlined in EPA method 3051A (U.S. Environmental Protection Agency, 2007). The sediment was dried in an oven for 24 hours. For each sample, 0.5-g of the dried sediment was 53
placed into a XP-1500 Teflon vessel. A combination of 9-mL of HNO3 and 3-mL of HCl was
then added to each vessel. The vessels were left until the reactions went through to completion.
When the reactions subsided, the vessels were capped and microwaved in a CEM
MARSXpress system. The vessels were then vented for 2 hours in a fume hood prior to
removing the caps. After venting, each sample was filtered through 11-µm filter paper into a 50-
mL flask. The remainder of the flask was filled with filtered water. The diluted sample was then
placed in an acid-washed polypropylene bottle and refrigerated until the analysis.
Elemental concentrations were determined using a Perkin-Elmer Model 1000/2000 ICP-
OES with a carrier of ultra high purity (UHP) argon gas (Roberts et al., 2007). Analyzed
elements included Cu, Mg, Mn, Na, Pb, Sr, and Zn. The necessary standards and blanks were
also used (Shacklette and Boerngen, 1984).
Eqn. 8 involves the first part of a two-step calculation used to determine the amount of
stock solution necessary to add for each element to make the standard solutions (modified from
U.S. Environmental Protection Agency, 2007).
S = (Cest*V)/W (Eqn. 8)
where S = sample concentration (mg/kg), Cest = estimated concentration of the element (mg/L),
V = volume of the sample solution (L), and W = weight of original sample prior to digestion
(kg). This equation accounts for having a 0.5-g sediment sample diluted in a 50-mL sample
solution. The standards used to analyze the samples were prepared using stocks solutions. A
stock solution is a 1000-mg/kg solution of each element. This solution needed to be diluted to
achieve the proper concentration in the standard. To make a standard, the concentration of each element must be estimated using sample concentrations obtained from similar types of materials 54
in previous studies (Table 5). A low, average, and high concentration standard can then be
prepared.
Eqn. 8 was rearranged to solve for Cest, the estimated element concentration. The sample
concentration, S, was determined using a previous study (Shacklette and Boerngen, 1984). It is
reported in mg/kg or µg/g. The volume of the sample solution, V, is the volume of liquid that
contains the digested sediment sample previously prepared. In this case, all sample solutions
were made in 50-mL flasks. To account for unit conversions, 50-mL was multiplied by 0.001 to
convert to L. W is the weight of original sample prior to digestion. All samples are within +/-
0.0003-g of 0.5-g, thus a standard value of 0.5-g was used. This value multiplied by 0.001 to
convert to kg. Once all of the necessary numbers were inserted, Cest was solved for. These
calculated values are the estimated concentration of each element (Table 5).
The next step in the process of making the standards involved the construction of a
simple ratio.
A/VStd = Cest /CStock (Eqn. 9)
where A = amount of stock solution to add (mL), VStd = volume of the standard (mL), Cest = estimated concentration (mg/kg), and CStock = concentration in the stock solution (mg/kg).
Because the standard is primarily composed of water, the concentration in the standard, C, was
converted from mg/L to mg/kg under the assumption that 1-L of water = 1-kg. The purpose of
Eqn. 9 was to determine the amount of stock solution, A, needed to generate the specific concentrations of each element, Cest, that were calculated using Eqn. 8 in Table 5. Eqn. 9 was
rearranged to solve for the amount of stock solution to add, A. The total volume of the standard,
VStd, was 100-mL because each standard was prepared in a 100-mL flask. The volume of the
stock solution, VStock, was 1000-mg/kg. The element concentration, Cest, was the Cest value 55
Table 5. Calculation of Element Concentrations in Standards for ICP-OES Analysis. Cest Cest Cest S Avga S Lowb S Highc Wd Avgf Lowg Highh Element (mg/kg) (mg/kg) (mg/kg) (kg) Ve (L) (mg/L) (mg/L) (mg/L) Cu 10 2 100 0.0005 0.05 0.10 0.02 1.00 Mg 10000 500 25000 0.0005 0.05 100.00 5.00 250.00 Mn 250 10 1000 0.0005 0.05 2.50 0.10 10.00 Na 5000 100 25000 0.0005 0.05 50.00 1.00 250.00 Pb 10 2 100 0.0005 0.05 0.10 0.02 1.00 Sr 50 2 500 0.0005 0.05 0.50 0.02 5.00 Zn 50 2 1000 0.0005 0.05 0.50 0.02 10.00 aSample concentration for average standard (Shacklette and Boerngen, 1984). bSample concentration for low standard (Shacklette and Boerngen, 1984). cSample concentration for high standard (Shacklette and Boerngen, 1984). dWeight of sample prior to analysis. All samples were 0.5-g (0.0005-kg). eVolume of the sample solution. All solutions were prepared in 50-mL (0.05-L) flasks. fEstimated concentration of each element in the average concentration stock solution, calculated as Cest Avg = (W*S Avg)/V. gEstimated concentration of each element in the low concentration stock solution, calculated as Cest Low = (W*S Low)/V. hEstimated concentration of each element in the high concentration stock solution, calculated as Cest High = (W*S High)/V.
56
calculated from Eqn. 8. These Cest values were inserted to calculate the amount of stock solution
to add to the standard for each element (Table 6). For each standard, the calculated amount to
add was measured into a 100-mL flask using disposable or glass pipettes. The remaining volume
was filled with filtered water and the standard was ready for analysis. The amount of each
element added, A, was recorded in the software program associated with the ICP-OES.
Sedimentation Rates
Six sedimentation rates were calculated using the blue OSL ages from two different
locations (Table 7). To calculate one sedimentation rate, the thickness of material between two
known dates was calculated. This thickness is equivalent to the difference in depths, d1. The
time difference, t1, between the adjacent dates was also calculated. The thickness divided by the
time difference is the sedimentation rate, S1.
S1 = d1/t1 (Eqn. 10)
The sedimentation rates at location 09OR-5 correspond to samples OR-09-1 through OR-09-3
(Table 7). The sedimentation rates at location 09OR-6 correspond to samples OR-09-4 through
OR-09-6.
Sediment Budget
Interpreted Change in Storage
Intrabasinal storage is primarily in an anthropogenic fill-terrace that is easily recognized in the field and on topographic maps. The volume of sediment in storage between 1959 and 57
Table 6. Calculation of Standards for ICP-OES Analysis.
Cest Cest Cest A A a b c d e f g h Avg Low High CStock VStd A Avg Low High Element (mg/L) (mg/L) (mg/L) (mg/kg) (mL) (mL) (mL) (mL) Cu 0.10 0.02 1.0 1000.0 100.0 0.01 0.00 0.10 Mg 100.0 5.0 250 1000.0 100.0 10.00 0.50 25.00 Mn 2.5 0.1 10 1000.0 100.0 0.25 0.01 1.00 Na 50.0 1.0 250 1000.0 100.0 5.00 0.10 25.00 Pb 0.10 0.02 1.0 1000.0 100.0 0.01 0.00 0.10 Sr 0.50 0.02 5.0 1000.0 100.0 0.05 0.00 0.50 Zn 0.50 0.02 10 1000.0 100.0 0.05 0.00 1.00 aEstimated concentration of each element in the average concentration stock solution, calculated in Table 6a. bEstimated concentration of each element in the low concentration stock solution, calculated in Table 6a. cEstimated concentration of each element in the high concentration stock solution, calculated in Table 6a. dConcentration of each element in the stock solution. All stock solutions have a concentration of 1000-mg/kg. eVolume of the standard solution. Each standard was prepared in 100-mL flask. fAmount of each element to add to the average standard solution to obtain the desired concentration, Cest Avg. Calculated as A Avg = VStd*(Cest Avg/Cstock) gAmount of each element to add to the low standard solution to obtain the desired concentration, Cest Low. Calculated as A Low = VStd*(Cest Low/Cstock) hAmount of each element to add to the high standard solution to obtain the desired concentration, Cest High. Calculated as A High = VStd*(Cest High/Cstock)
58
59
1980 was determined using data from Table 7. The 1959 date was chosen because samples of a known depth were dated to this age so the amount of material accumulated since that time is well constrained. The period of 1959 to 1980 was also when rapid population growth occurred upstream of the study area (Fig. 7). Therefore, this package of material can be used to determine sedimentation rates which are representative of the urbanization period in the watershed.
To calculate this volume, both the lateral and vertical extent of the material were determined (Table 8). The thickness of the material is location dependent, so locations 09OR-5 and 09OR-6 were chosen (Fig. 3). The aerial extent of the fill-terrace was calculated using topographic maps superimposed by a grid. The grid was created using the map scale, and the number of grid squares was counted using logical reasoning. The fill-terrace can be traced upstream until the confluence of Schreiber Ditch with Ten Mile Creek. The area of the fill- terrace between the confluence and the study area was calculated and multiplied by the thickness of alluvium in the fill-terrace from each location in order to obtain the volume of material in floodplain storage.
To determine the amount of eroded material necessary to accumulate this volume, a similar approach was taken. The total upstream area of the watershed was calculated using a grid. The storage volume was divided by the total upstream drainage basin area to find the thickness of material eroded upstream. This approach assumes a uniform thickness of the material in fill-terrace storage, which essentially treats the package as a rectangle. As such, it provides a maximum volume. It is more likely that this package wedges out on either side of the river, so a more representative volume would be as little as half as much.
60
Table 8. Determination of Volume of Sediment in Floodplain Storage Since 1959 Flood. Area of Materiala (km2) 3.30 Thickness of Materialb (cm) 158 Thickness of Materialc (km) 0.00158 Total Volume of Materiald (km3) 0.0052 aArea of material presently in floodplain storage as anthropogenic terraces. bAverage thickness of the upper package of material between OR-09-3 and the top of the section at 09OR-5, and between OR-09-6 and the top of the section at 09OR-6. cThickness of Material (cm)*10-5 dArea of Material*Thickness of Material (km)
61
Input Calculated Using USLE
In the Ottawa River watershed, the only significant source of input was assumed to be
from erosion. As such, the amount of input could be calculated using the Universal Soil Loss
Equation. The USLE value was determined using Eqn. 11 (Wischmeier and Smith, 1978).
A = R*K*LS*C*P (Eqn. 11)
where A = soil loss per unit area (tons/acre year-1), R = rainfall and runoff factor, K = soil
erodibility factor, LS = slope-length and slope-steepness factor, C = cover and management factor, and P = support practice factor.
R includes both an erosion index value, EI, and a value for thaw and snowmelt, Rs (Table
9a).
R = Rs + EI (Eqn. 12)
where Rs = 1.5 times the average local precipitation between the months of December and
March, as measured in inches of water, and EI = erosion index value. In this study, R was
determined from examining historical precipitation records to calculate Rs and using linear
interpolation of average annual erosion index values to find EI (The Weather Channel, 2010; Fig.
1 in Wischmeier and Smith, 1978).
The K value, or soil erodibility factor, relates to the properties of the soil and is equal to the soil loss rate per erosion index unit (Wischmeier and Smith, 1978). It can be determined using a soil-erodibility nomograph if a number of values are known including percent silt + very fine sand, percent sand (0.10 to 2.0-mm), percent organic matter, soil structure, and permeability
(Fig. 3 in Wischmeier and Smith, 1978). The K factors used in this study were found in tables in
the Field Office Technical Guides of the counties in the watershed (Appendix C; USDA NRCS,
2004, 2010). The values for the soil types in each soil association were averaged then multiplied 62
Table 9a. R Factor Calculations for the Ottawa River Watershed. a b c EI RS R Minimum 110 3.48 113.48 Maximum 115 3.48 118.48 Average 112.5 3.48 115.98 aThe erosive index was determined though linear interpolation (Wischmeier and Smith, 1978). bThe value for thaw and snow melt was calculated as 1.5 times the average precipitation from December through March (The Weather Channel, 2010). c The rainfall and runoff factor is equivalent to RS + EI.
63 by the area of the soil association to obtain a weighted K factor (Table 9b). These weighted K factors were totaled and divided by the total area of the soil associations to determine an average
K factor for each county.
The LS factor includes both slope-length and slope-steepness (Wischmeier and Smith,
1978). In general, the LS factor can be obtained if the percent slope and slope length are known for the area (Haan et al., 1994). For the two counties in Ohio, the slope-length and slope- steepness values were averaged for each soil association and an overall average for the county was tabulated (USDA NRCS, 2004). The county average was used to find the LS factor from a graph, assuming a moderate ratio for rill to interrill erosion as shown in Table 9c (Haan et al.,
1994). For the two Michigan counties, the slope-length and slope-steepness factors were unknown. However, the relatively flat topography allowed for the assumption that these counties would have similar LS values. As a result, the LS factors from the Ohio counties were averaged and applied to the Michigan counties.
The C factor, or cover and management factor, compares the soil loss from an area with certain cover and management to an area in tilled continuous fallow (Wischmeier and Smith,
1978). This factor can be determined based on the type of canopy and average fall height of winter drops, the percent of canopy cover, and the type and percent of ground cover (U.S. Soil
Conservation Service, 1975). In this study, the C factor was determined using multiple approaches. For agriculture-dominated counties, including Fulton, Lenawee, and Monroe, the C factor was selected under the assumption of corn and soybean crop rotations. The corn after soybeans with 30% cover C value is equivalent to 0.29, and the soybeans after corn with 30% cover C value is 0.19 (Natural Resources Conservation Service, 2003). These values are added together to determine the total C value of 0.48. For Lucas County, two separate C factors were 64
Table 9b. K Factors for Fulton, Lucas and Monroe County. Area Avg K Weighted Fulton County Soil Associations (mi2) factora K factorb 1 - Hoytville-Nappanee 13.00 0.31 3.97 3 - Hotyville-Blount 10.38 0.34 3.48 7 - Ottokee-Granby-Tedrow 0.25 0.16 0.04 8 - Haskins-Blount-Oshtemo 2.88 0.32 0.93 9 - Mermill-Haskins 6.25 0.35 2.16 Total Area 32.8 -- 10.6 Average 0.32c
Area Avg K Weighted Lucas County Soil Associations (mi2) factor K factor 2 - Del Rey-Lenawee 9.25 0.36 3.28 4 - Hoytville-Nappanee-Mermill 24.00 0.31 7.44 5 - Bixler-Dixboro 20.25 0.19 3.75 6 - Colwood-Bixler 2.13 0.23 0.48 7 - Mermill-Metamora-Haskins 13.00 0.30 3.86 8 - Granby-Ottokee-Tedrow 31.75 0.16 4.97 9 - Urban Areas 19.25 unranked unranked Total Area (excluding Urban Areas) 100.4 -- 23.8 Average 0.24c
Area Avg K Weighted Monroe County Soil Associations (mi2) factor K factor 2 - Hoytville-Nappanee 6.38 0.33 2.07 3 - Oakville-Tedrow-Granby 4.25 0.16 0.69 6 - Pewamo-Selfridge-Blount 18.00 0.28 5.04 Total Area 28.6 -- 7.8 Average 0.27c Note: Soil association data was unavailable for Lenawee County, MI. aCalculated as the average K factor for each soil type in the soil associations. bCalculated as Area*Avg K factor. cCalculated as Total of Weighted K factors/Total Area.
65
Table 9c. LS Factors for Fulton and Lucas County. Avg. Avg. Fulton County Soil Associations Gradienta Lengthb 1 - Hoytville-Nappanee 1.75 199.50 3 - Hotyville-Blount 2.00 178.83 7 - Ottokee-Granby-Tedrow 2.50 162.00 8 - Haskins-Blount-Oshtemo 2.67 178.22 9 - Mermill-Haskins 1.50 249.50 Average 2.10 193.61 LS Factorc 0.32
Avg. Avg. Lucas County Soil Associations Gradienta Lengthb 4 - Hoytville-Nappanee-Mermill 1.33 332.67 5 - Bixler-Dixboro 1.65 151.00 6 - Colwood-Bixler 1.65 225.00 7 - Mermill-Metamora-Haskins 1.67 233.00 8 - Granby-Ottokee-Tedrow 2.00 134.67 9 - Urban Areas -- -- 2 - Del Rey-Lenawee 1.33 102.00 Average 1.60 196.39 LS Factorc 0.27 Note: Average gradient and length data were unavailable for Lenawee and Monroe counties. aCalculated as the average gradient for each combination of soil types. bCalculated as the average length for each combination of soil types. cCalculated using Fig. 8.13 (in Haan et al., 1994) and assuming a moderate ratio of rill to interrill erosion.
66
calculated depending on land use. In the agricultural areas, the same C factor from the other
counties was used. For the suburban areas, a C factor of 1.0 was selected under the assumption
that the land was kept free from vegetation, as it would in construction areas (Martin et al.,
2003).
The P factor, or support practice factor, takes into account support practices used by
farmers to decrease erosion (Wischmeier and Smith, 1978). The P factor can be determined
based on the land slope percentage and the type of erosion control technique in use (U.S. Soil
Conservation Service, 1975). Common techniques implemented by farmers include contouring,
contour strip cropping, contour irrigated furrows, and terracing. For the Ottawa River watershed,
farmers implement strip cropping. This practice involves the use of alternating strips of sod and row crops or small grain (Wischmeier and Smith, 1978). The same P factor was used throughout most of the watershed and was selected based on a 2.0-7% land slope and the use of contour strip cropping (U.S. Soil Conservation Service, 1975). However, in the suburban areas, a P factor of
1.0 was used which can be applied to typical land cover associated with suburbanization including asphalt or concrete pavement, packed bare soil, or sod grass (Table 9-3 in Fifield,
2004).
The soil erosion, A, was calculated based on the above five factors (Table 9d). A total of five “A” values were calculated for the watershed. The values were dependent upon known conditions in different areas. “A” values were calculated for the portions of Fulton, Lenawee, and Monroe County in the Ottawa River watershed. In Lucas County, two “A” values were calculated based on land use. One value was determined for the agricultural area and one value was determined for the suburban area. The “A” value was measured in tons/acre year-1, and was
67
Table 9d. USLE Values for the Ottawa River Watershed. Aa Rb Kc LSd Ce Pf Fulton County 1.4 115.98 0.32 0.32 0.48 0.25 Lenawee County 1.2 115.98 0.28 0.30 0.48 0.25 Lucas County Agricultural 0.9 4 115.98 0.25 0.27 0.48 0.25 Suburban 7.8 115.98 0.25 0.27 1.0 1.0 Monroe County 1.1 115.98 0.27 0.30 0.48 0.25 aSoil erosion as measured in tons/acre year-1. bRainfall and runoff factor (Table 9a). cWeighted soil erodibility factor (Table 9b). dSlope-length and slope-steepness factor (Table 9c). eCover and management factor. fSupport practice factor.
68
converted to a volume in km3 to allow for its comparison with the volume in fill-terrace storage
(Table 9e).
Output
The output or sediment yield was calculated in two ways. One approach was to calculate
the output using the sediment budget equation with the calculated values for input and storage.
By inserting the known volumes for input and storage, the volume of output could be solved for
(Table 10).
Sediment Delivery Ratio
The other approach involved the use of the sediment delivery ratio (modified from Lu et
al., 2006).
SDR = (Y/E)*100 (Eqn. 13)
where SDR = the sediment delivery ratio (%), Y = sediment yield (tons/acre year-1), and E = soil
erosion (tons/acre year-1). The sediment delivery ratio, SDR, is a function of the drainage area size and was solved for using the calculated input and output values. Soil erosion, E, is the input value determined using the Universal Soil Loss Equation (USLE). The sediment yield, Y, is the output value calculated using the sediment budget equation. When the soil erosion and sediment
yield are inserted into Eqn. 13, the sediment delivery ratio can be determined (Table 11a).
As a final check, this ratio was compared to the sediment delivery ratio obtained from a
graph showing the relationship between drainage basin size and sediment delivery ratio (Boyce,
1975). By knowing the size of the Ottawa River drainage basin, the sediment delivery ratio was
estimated to be 8% using the graph. This estimated SDR was compared to the calculated SDR in 69
70
Table 10. Sediment Yield Calculations for the Ottawa River Watershed. Inputa (*10-3) Storageb (*10-3) Outputc (*10-3) Minimum 3.2 2.6 0.60 Maximum 3.2 5.2 -2.0 aAverage volume of input, as measured in km3, over a 21 year period (Table 9e). bVolume of material in fill-terrace storage as measured in km3 (Table 8). A minimum of half of the original calculated value was used under the assumption that the fill-terrace package likely wedges out on either side of the river rather than forming a rectangle. The volume of a wedge would be half the volume of a rectangle. cSediment yield (output), measured in km3, determined using the sediment budget equation, where input - storage = output.
71
Table 11a. Sediment Delivery Ratios for the Ottawa River Watershed. Ea (*10-3) Yb (*10-3) SDRc (%) Minimum 3.2 0.60 19 Maximum 3.2 -2.0 -63 aVolume of soil erosion (input) as measured in km3 (Table 9e) bVolume of output as measured in km3. Calculated in Table 10. cSediment delivery ratio determined using Eqn. 13.
72
Table 11a. An 8% sediment delivery ratio means that 92% of eroded sediment is stored within the drainage basin. Table 11b details the estimated volume of output based on the calculated volume of input (Table 9e) and the estimated sediment delivery ratio of 8% (Boyce, 1975). This estimated output was then used with the calculated input to determine an estimated volume of material in storage based on the sediment budget equation (Table 11b).
73
Table 11b. Estimated Sediment Delivery Ratio, Sediment Yield, and Storage. a -3 b c -3 d -3 E (*10 ) SDRest (%) Yest (*10 ) Sest (*10 ) 3.2 8 0.26 2.9 aVolume of soil erosion as measured in km3. Equivalent to the output values in Table 9e. bEstimated sediment delivery ratio of 8% or 0.08 (Boyce, 1975). cEstimated sediment yield based on estimated sediment delivery ratio and calculated soil erosion (Eqn. 13). dEstimated volume of material (km3) in storage based on calculated input and estimated output using the sediment budget equation (Eqn. 1).
74
RESULTS
Lithofacies
Lithofacies Gm
The Gm facies consists of massive, clast-supported, rounded, poorly sorted pebble gravel with a fine-grained sandy matrix and wood debris (Table 12a and Fig. 14a). According to the
Munsell color chart, the facies is dark gray in color (7.5YR4/0). The thickness ranges from 3-cm
to 8-cm. It was found in four locations in or directly adjacent to the modern channel.
Interpretation: The Gm facies represents a gravel bar or pool lag deposit which forms as
coarser-grained materials are plucked from the bed of the stream and transported as bedload
sheets. As each sheet becomes progressively better sorted, the critical shear stress required to
move the sheet increases therefore making it harder to keep in motion. Eventually, the required
shear stress is too great and the bedload sheet stalls until it again becomes poorly sorted via infiltration of the sandy matrix (Whiting et al., 1988).
Lithofacies Se
The Se facies is composed of massive, sub-rounded to rounded, moderately well sorted, medium-grained sand with clay intraclasts and wood debris (Table 12a). The color of the facies is light yellowish brown (2.5Y6/4). It is 9.5-cm thick and was found at location 09OR-5.
Interpretation: The Se facies formed from deposition of bed load following a flood. The clay intraclasts were formed from clay which slumped into the river and were carried downstream.
The clay was mixed with bed load and wood debris and deposited to form the Se facies. 75
Table 12a. Lithofacies Code. Code Lithology Sed. Structures Interpretation Gm Clast-supported, rounded, poorly Massive Bar transported as a sorted, pebble gravel bedload sheet Se Sub-rounded to rounded, moderately Massive Flood horizon with bank well sorted, medium-grained sand failure debris with clay intraclasts and wood debris Sl Sub-rounded to rounded, well Laminated Upper plane bed sorted, medium-grained sand
Smc Rounded, well sorted, medium- to Massive Flood horizon coarse-grained sand
Smf Rounded, well sorted, fine-grained Massive, rooted Soil horizon sand Sp Sub-rounded, moderately well Massive Bar sorted, coarse- to v. coarse-grained pebbly sand Sr Asymmetric ripple laminated, well Ripple laminated Ripples rounded, moderately well sorted, fine- to medium-grained sand St Well rounded, moderately well Trough cross- 3-D Dunes sorted, medium- to coarse-grained bedded sand Stf Well rounded, moderately well Festoon cross- 3-D Dunes sorted, medium- to coarse-grained bedded sand Stl Well rounded, moderately well Low-angle cross- 3-D Dunes sorted, medium- to coarse-grained bedded sand (Continued in Table 12b) 76
Figure 14. (a) Lithofacies Gm and Sp from a vibracore at location 09OR-10. (b) A number of different lithofacies from a push core at location 09OR-7. (c) Lithofacies SSm and Smc from a vibracore at location 09OR-10. 77
Lithofacies Sl
The Sl facies consists of laminated, sub-rounded to rounded, well sorted, medium-grained
sand (Table 12a and Fig. 14b). The unit is found at location 09OR-7 near the elevation of the
mean daily stage height. It is 2-cm thick and brown in color (10YR4/3). The Sl facies lacks any
wood or shell debris.
Interpretation: This facies formed in an upper flow regime. During flooding, the energy
conditions in a river rise. If the flow velocity is fast enough, the bedforms can transition from
ripples, to dunes, to upper-flow-regime plane bed. These energy conditions were met as the Sl
facies was deposited.
Lithofacies Smc
The Smc facies consists of massive, rounded, well sorted, medium- to coarse-grained
sand that may contain shell fragments, root casts, carbonized wood, and/or wood debris (Table
12a and Fig. 14c). It ranges from 0.5-cm to 17-cm thick and can be found at six locations. The color varies with depth. When saturated, the color of Smc at depths greater than 90-cm at
location 09OR-10 and 70-cm at location 09OR-11 is light olive brown (2.5Y5/4). When moist,
the color of Smc near the mean daily stage height is dark gray (10YR4/1). When dry, the Smc
facies above the water table is white (10YR8/2). The Smc facies has 19.2% porosity and contains
of 0.12% organic material. The grain size distribution includes 77.2% sand and 22.8% clay
which characterize this facies as a sandy clay loam (Table B-1 and Fig. B-1). The grain size
distribution of this facies, sample number 09LW-14, can be found in Appendix B (Table B-2a
and Fig. B-2). 78
Interpretation: The Smc facies was transported as bed load during a flood event and was
subsequently deposited as a channel bar or in the channel margin. The facies is commonly
mixed with woody material contributed by the floodplain and shell fragments from the channel.
At low stage following a flood, the sediment is exposed and the surface may become re-
vegetated with plant roots that grow down into the sand. If a successive flood occurs, the sand
and any overlying deposits can become buried which causes plants to die and root molds to be
created when their roots are broken down. This process explains the many root casts seen in the
upper part of Smc layers.
Lithofacies Smf
The Smf facies consists of massive, rooted, rounded, well sorted, fine-grained sand (Table
12a). It is 18-cm thick and was found at location 09OR-6. The unit is destratified and lacks any wood debris or sedimentary structures.
Interpretation: The Smf facies represents the parent material of the present day soil profile. It is
located directly below a thick package of rooted silt that extends to the surface. Its proximity to
this layer, lack of sedimentary structures, and presence of roots support this interpretation.
Lithofacies Sp
The Sp facies is composed of massive, sub-rounded, moderately well sorted, coarse- to
very coarse-grained pebbly sand (Table 12a and Fig. 14a). It may contain wood and shell
fragments and varies from 3-cm to 11.5-cm thick. The Sp facies was found in three locations
along the modern channel. The color ranges from dark gray (10YR4/1) to very dark grayish
brown (10YR3/2). 79
Interpretation: The Sp facies represents bar deposits that formed in the modern channel. This
pebbly sand bar indicates slightly lower energy conditions than those which allowed for the
deposition of the gravel-rich Gm facies. The coarse grain sizes, location with respect to other
facies, and inclusion of shell fragments support the interpretation of the Sp facies as a bar.
Lithofacies Sr
The Sr facies consists of asymmetric ripple laminated, well rounded, moderately well sorted, fine- to medium-grained sand (Table 12a). This facies was found in two layers at location 09OR-6. The unit is dark brown in color and ranges from 2-cm to 4-cm thick.
Interpretation: The Sr facies represents asymmetrical or current ripples that formed either in the
channel margin, or lower-energy portions of the channel such as the upper parts of point bars,
deposits in backwater eddies, or in the lee of obstacles.
Lithofacies St
The St facies consists of trough cross-bedded, well rounded, moderately well sorted,
medium- to coarse-grained sand (Table 12a). It was found at two locations (09OR-5 and 09OR-
6) and is 13-cm to 30-cm thick. The unit is light brown and may contain shells and wood
fragments up to 10-cm long. The lower contact is erosional. An example of the grain size
distribution of the St facies can be found in Appendix B (Table B-2a and Fig. B-3). The porosity is 3.7%. The grain sizes include 93.4% sand and 6.6% silt, which indicate that this facies is sand
(Table B-1 and Fig. B-1).
Interpretation: Trough cross-bedded sands are channel deposits. These indicate the migration of
3-dimensional dunes across the lower portion of the point bar. 80
Lithofacies Stf
The Stf facies consists of festoon cross-bedded, well rounded, moderately well sorted,
medium- to coarse-grained sand with shell and wood fragments (Table 12a). The unit is 18-cm
thick with an erosional lower contact. It can be found at location 09OR-6.
Interpretation: These deposits are identical to facies St. This unit formed as 3-dimensional
dunes migrated across the substrate in an orientation perpendicular to the outcrop.
Lithofacies Stl
The Stl facies is low-angle cross-bedded, well rounded, moderately well sorted, medium-
to coarse-grained sand with shell fragments (Table 12a and Fig. 14b). It may also contain root
casts and wood debris. The color was either white or light brown. The facies was found at
locations 09OR-6 and 09OR-12 and ranges from 8-cm to 32.5-cm thick. The cosets of low-angle
cross-bedding within these layers range from 6-cm to 15.5-cm thick.
Interpretation: These deposits are identical to facies St. As previously indicated, cross-bedded
sand indicates the migration of 3-dimensional dunes across the point bar in the channel.
Lithofacies SSd
The SSd facies is a discontinuous silt layer that lacks any wood debris or shell fragments
(Table 12b). The upper contact is erosional. The unit was found at locations 09OR-6 and 09OR-
5 and is up to 7-cm thick. It is dark brown to brownish gray in color.
Interpretation: This facies is interpreted to represent the erosional remnants of a continuous silt layer that was scoured into during a subsequent flooding event.
81
Table 12b. Lithofacies Code. Code Lithology Sed. Structures Interpretation SSd Silt Discontinuous bedding Scoured SSm Silt Massive Drape SSr Silt Rooted Soil Fm Mud Massive Drape
Fmp Mud with mottling Massive Soil horizon
Fmc Carbonaceous mud Massive Hydromorphic paleosol
HdSSS Heterolithic with lenses of silt in Lenses of silt in sand Flood horizon with mud rounded, well-sorted, medium- drape grained sand matrix with wood debris HdSFm Heterolithic with lenses of clay in Lenses of clay in sand Flood horizon with mud rounded, well-sorted, fine- drape grained sand P Peat with minimal sand matrix Massive Histosol W Well rounded, well sorted, Massive Flood horizon of woody medium-grained sand with material abundant wood debris OS Sub-rounded, moderately to well Massive Flood horizon with leaf sorted, fine- to medium-grained litter sand with leaf litter
OFm Interbedded clay and leaf litter Laminated Fine-grained material settling from suspension following flood
82
Lithofacies SSm
The SSm facies consists of massive silt (Table 12b and Fig. 14c). It was found at nine
locations across the study area. The thickness varies from 1-cm to 43-cm. It may contain carbonized wood or mottling, which is indicative of water-saturated conditions. The grain size distribution of the SSm facies, sample number 09LW-15, can be found in Appendix B (Table B-
2b and Fig. B-4). This facies has a porosity of 19.3% and contains 0.12% organic material.
Grain sizes consist of 36.8% sand and 63.2% silt, which characterize the SSm facies as a silt
loam (Table B-1 and Fig. B-1).
Interpretation: The SSm facies is interpreted to represent silt falling out of suspension during the waning stages of a flood.
Lithofacies SSr
The SSr facies is composed of rooted silt (Table 12b). This facies comprised the
uppermost layer at seven locations. It lacks any sedimentary structures and is dark brown
(10YR3/3) in color. The thickness varies from 6-cm to 105-cm.
Interpretation: The SSr facies is identical to facies SSm but rooted. It is interpreted to represent
part of the present day soil profile due to its location directly below the vegetated surface and
lack of sedimentary structures.
Lithofacies Fm
The Fm facies is a massive silty clay deposit that may contain wood debris (Table 12b
and Fig. 14b). It ranges in thickness from 0.5-cm to 8-cm and was found at nine locations across
the study area. 83
Interpretation: This facies represents the deposition of fine-grained silt and clay from suspension during the waning stages of a flood or during periods of low discharge.
Lithofacies Fmp
The Fmp facies consists of massive, mottled clay that may contain carbonized wood
(Table 12b). It was found at locations 09OR-1 through 09OR-4 at depths of 64-cm to 123-cm below the surface. The thickness ranges from 30-cm to 56-cm.
Interpretation: This facies is identical to facies Fm except that it contains mottling. It is interpreted to represent the lower portion of the present day soil profile. These layers are clay- rich due to the translocation of clay-sized particles and clay minerals as part of the process of pedogenesis.
Lithofacies Fmc
The Fmc facies consists of massive carbonaceous mud (Table 12b). It was found at location 09OR-6 and is black (10YR2/1) in color. When exposed, this layer released a strong odor of H2S. It lacks any sedimentary structures and is 4-cm thick. This facies is associated with peats (Lithofacies P). The grain size distribution of the Fmc facies, sample number 09LW-9, can be found in Appendix B (Table B-2a and Fig. B-5). This facies possessed a porosity of 28.6% and an organic content of 0.42%. It is composed of 53.3% sand and 46.7% silt, which characterize it as a sandy loam (Table B-1 and Fig. B-1).
Interpretation: This facies is identical to facies Fm except that it is rich in fine-grained carbon rather than wood debris as indicated by its black color. Because of its association with peats, the carbonaceous mud is interpreted to represent a hydromorphic paleosol that formed in a riparian 84 wetland. Its formation relates to a change in the input of siliciclastics where a minimal input leads to the formation of a peat, and a high input leads to the formation of carbonaceous mud.
Lithofacies HdSSS
The HdSSS facies is heterolithic in texture and was found at location 09OR-11 (Table
12b). It contains lenses of silt in a massive, rounded, well-sorted, medium-grained sand matrix with wood debris. The facies ranges from 8-cm to 21-cm thick. The sand is light grayish brown
(2.5Y6/2) and the silt is dark grayish brown (10YR4/2).
Interpretation: The HdSSS facies includes sand deposited as bedload during a flood with mud drapes. Thus it is representative of a flood rhythmite and forms in the floodplain when sand is deposited as a result of hydraulic changes as flows transition from channelized to unchannelized.
Lithofacies HdSFm
The HdSFm facies is heterolithic sand and clay that is similar to the HdSSS facies (Table
12b). The HdSFm facies was found at three locations and is composed of massive, rounded, well- sorted, fine-grained sand with clay lenses. It may also contain wood debris, shell fragments, carbonized wood, root casts, and mottling. The thickness ranges from 10.5-cm to 29.5-cm.
Interpretation: This facies is identical to HdSSS except that it contains clay lenses rather than silt lenses. As with the HdSSS facies, the HdSFm facies is interpreted as the deposition of sandy bed load in the channel margin area during a flood. The sand was subsequently topped with mud drapes. Thus, this facies is also representative of a flood rhythmite.
85
Lithofacies P
The P facies is an organic layer that consists of peat with minimal sand matrix (Table 12b
and Fig. 14b). It is found at three locations and ranges from 2-cm to 10-cm thick and is black
(10YR2/1) in color. At location 09OR-5, the size of wood debris increased upward in the layer.
Interpretation: The P facies is a paleo-histosol (buried organic soil) that formed in a riparian
wetland environment. The upward increase in organic matter and wood debris results from a
decreased input of siliciclastic sediment.
Lithofacies W
The W facies is an organic deposit that is composed of massive, well rounded, well
sorted, medium-grained sand with abundant wood debris (Table 12b and Fig. 14b). It was found
at seven locations at depths of approximately 10-cm above to 75-cm below mean daily stage
height. The facies ranges from 2-cm to 10-cm thick and is dark gray (10YR4/1) in color. The
distribution of grain sizes for the W facies, sample number 09LW-8, can be found in Appendix B
(Table B-2a and Fig. B-6). The porosity for this facies is 15.2%. The grain size percentages
include 94.4% sand, 4.0% silt, and 1.6% clay which indicate this facies is sand (Table B-1 and
Fig. B-1).
Interpretation: The W facies is interpreted as a flood horizon with woody material. Wood can become waterlogged and sink to the point of mixing with bedload. During a flood, this material can be deposited as a massive unit.
86
Lithofacies OS
The OS facies is an organic deposit that consists of leaf litter layers above massive, sub-
rounded, moderately to well sorted, fine- to medium-grained sand (Table 12b). This facies was
found at location 09OR-5 and 09OR-6. The thickness ranges from 1-cm to 7-cm. The sand is
gray (7.5YRN5/) in color and the leaf litter is black (10YR2/1).
Interpretation: The OS facies is interpreted as an organic layer that represents leaf litter that
settled above the deposition of sandy bed load following a flood. As such, it represents a flood
rhythmite.
Lithofacies OFm
The OFm facies is an organic deposit that consists of leaf litter layers above silty clays
(Table 12b and Fig. 14b). It was found at six locations and ranges from 0.5-cm to 16-cm thick.
The color ranges from very dark gray (10YR3/1) to black (10YR2/1). It is located at depths between 12-cm above and 50-cm below the mean daily stage height.
Interpretation: This facies is identical to facies OS, except finer-grained. The OFm facies
represents the settling out of clay suspended load following a flood that is topped with leaf litter.
It is another type of flood rhythmite.
Lithofacies Assemblages
Channel Facies Assemblage
The channel facies assemblage includes the Gm, Se, Sl, Smc, Sp, St, Stf, and Stl facies
(Table 13). These lithofacies are all medium-grained sand to gravel that can be found in and 87
Table 13. Lithofacies Assemblages. Assemblage Lithofacies Interpretation Inundite Massive clay to massive silt (SSm, Deposition of bed load facies Fm, SSd) alternating with massive followed settling out of assemblage to cross-bedded sand (Se, Smc, St, fine-grained material and Stl, Stf) that may contain wood organic debris from debris and clay or silt lenses suspension (HdSSS, HdSFm) Modern soil Basal Fm overlain by SSm and Development of modern facies SSr soil profile assemblage
Channel Coarse-grained and high energy Deposition in and along facies deposits (Gm, Sl, Sp) modern channel assemblage Wetland Fmc and P surrounded by W, Os, Flood deposits in one or facies Ofm a series of riparian assemblage wetlands
88
along the modern channel. They are interbedded with <2.5-cm thick SSm or SSd. The channel
facies assemblage can be found at locations 09OR-10, 09OR-11, and 09OR-6 (Figs. 15 and 15a).
Interpretation: These facies represent the downstream migration of bedforms as well as upper flow plane bed energy conditions likely coinciding with flooding. The SSm or SSd facies are deposited following flood events or during periods of low flow velocity.
Channel Margin Facies Assemblage
The channel margin assemblage includes a number of different lithofacies (Table 13).
The dominant feature of this assemblage is a thicker package of sand overlain by a thinner
package of silt or clay with or without leaf litter layers or wood debris. These packages are
interbedded and may differ in sedimentary structures or composition. However, this assemblage
can be found both above and below the organic floodplain facies assemblage (Fig. 15). At
locations 09OR-10 and 09OR-11, the layers are dark grayish brown (10YR4/2) to light grayish
brown (2.5Y6/2) and two of the silt layers contain carbonized wood. At location 09OR-12 and
09OR-5, the assemblage is darker brown and may contain wood fragments, shell fragments, or
mottling (Fig. 15).
Interpretation: The channel margin facies assemblage represents deposits of the upper point bar,
upper bank, or natural levee. These deposits form from deposition of bed load as flows transition
from channelized to unchannelized. After bed load deposition, fine-grained suspended load and
organic material settle out of suspension and form a thin layer of silt or clay. This process
repeats with subsequent flooding events as the deposits continue to build upward or outward.
89
90
Figure 15a. Key to symbols.
91
Clastic Floodplain Facies Assemblage
The clastic floodplain facies assemblage includes predominately thick coarse-grained
deposits (Smc or HdSFm) interbedded with thin fine-grained deposits (Fm or SSm) (Fig. 15).
This facies assemblage is topped with coarsening-upward vertical accretion (floodplain) deposits superimposed with modern soils. The sequence extends from the Fm facies at the base up to the
SSm and the SSr at the top (Table 13 and Fig. 16). The trend of this arrangement is a decrease in grain size with depth.
Interpretation: These deposits accumulated vertically due to flooding. The coarse-grained layer
of each rhythmite was deposited first followed by the thin fine-grained layer which settled out
from suspension. At the top of the sequence, modern soils are developing in the flood deposits.
The coarsening-upward sequence could reflect increased flooding across the fill-terrace as
channel storage decreases and floodplain storage increases, or possibly the preferential
translocation of clay-sized particles and clay minerals downward through the soil profile. As
soils develop, clay minerals and clay-sized particles are translocated from the upper soil horizons
to the lower soil horizons with the movement of meteoric water. For these soils, the parent
material is clastic floodplain deposits (Fig. 16). Therefore, the sequences contain both flood
deposits and soils.
Organic Floodplain Facies Assemblage
The organic facies assemblage consists primarily of the W, OS, and OFm lithofacies,
which are generally topped by the P or Fmc facies (Table 13 and Fig. 17). All of these deposits are rich in organic material and can be found throughout the study area (Fig. 15). 92
Figure 16. Examples of the clastic floodplain facies assemblage superimposed with the modern soil profile at four locations in the study area. All four of these sections were obtained using vibracoring.
93
94
Interpretation: These deposits represent the establishment of soil in one or a series of riparian
wetlands in the study area that were periodically flooded with clastics from the nearby channel.
The W and OS lithofacies represent the bedload material deposited during periodic flooding,
while the OFm lithofacies represents the suspended load deposits. The P and Fmc facies depict
periods of quiescence which allowed for soil formation. The P facies is a paleo-histosol or buried soil composed of peat. This indicates that the soil formed during periods of low clastic input. The Fmc facies is a paleo-entisol or paleo-inceptisol, which are buried soils that may show
weakly defined soil horizons. In the study area, the P and Fmc facies are interpreted to represent
A horizons. Underlying these facies are C horizons. These horizons are not part of the modern
soil profile due to their location in the section, organic-rich composition that is not present in modern-day conditions, lack of modern roots, and the presence of mottling and root molds.
Alluvial Stratigraphy
Upon correlation, four main packages of material were discovered (Fig. 17). These packages were correlated across the study area (Fig. 15). The lower package consists of channel and channel margin deposits. Overlying this package are widely correlatable organic floodplain deposits. Depending on the location, the organic floodplain deposits are topped with either channel or channel margin deposits. A particularly prominent channel margin deposit of trough cross-bedded, well rounded, moderately well sorted, medium- to coarse-grained sand was also correlated across the study area (Fig. 15). Overlying these layers are clastic floodplain deposits superimposed with modern soils.
95
Radiocarbon and Blue OSL Ages
According to the radiocarbon and blue OSL results, the ages of these packages vary from
4889 +/- 178 YBP to -9 +/- 5 YBP (Tables 14 and 15 and Appendix C). Seven ages were obtained for the organic floodplain deposits at three locations (Fig. 17). Four radiocarbon ages for this package are 4889 +/- 178 YBP, 4731 +/- 306 YBP, 4547 +/- 326 YBP, and 82.5 +/- 121
YBP. The 60 +/- 100 14C YBP sample is interpreted as contaminated. It was collected from the
channel bank and could have been recently eroded into. Three blue OSL ages are 1276 +/- 80
YBP, 561 +/- 55 YBP, and 421 +/- 40 YBP.
Further up section, three blue OSL ages were attained for the channel margin deposits
(Fig. 17). These ages include 231 +/- 15 YBP, -4 +/- 5 YBP, and -9 +/- 5 YBP. At location
09OR-5, the ages get progressively younger up section. At location 09OR-6, the sample with the
blue OSL age of -4 +/- 5 YBP was collected from the same layer of material as the sample with
an age of -9 +/- 5 YBP at location 09OR-5. These two ages are concordant and correspond with
the prominent trough cross-bedded sand layer (Fig. 15).
Sedimentation Rates
Based on the blue OSL ages, a number of sedimentation rates were calculated (Table 7).
These rates approximately correspond to periods of different land uses (Fig. 18). At location
09OR-5, the sedimentation rates were determined using samples OR-09-1 through OR-09-3.
Between a depth of 171.7-cm and 167.5-cm, there was a time span of 190 years. This works out
to a sedimentation rate of 0.022-cm/yr during the transition from swamp conditions to agricultural land use (Fig. 19). Further up section, there was a time span of 240 years between 96
Table 14. Blue OSL Ages and Conversions to Calendar Years. Blue OSL agesa Calendar Yearsb YBPc 480 +/- 40 1529 +/- 40 A.D. 421 +/- 40 YBP 290 +/- 15 1719 +/- 15 A.D. 231 +/- 15 YBP 50 +/- 5 1959 +/- 5 A.D. -9 +/- 5 YBP 1335 +/- 80 674 +/- 80 A.D. 1276 +/- 80 YBP 620 +/- 55 1389 +/- 55 A.D. 561 +/- 55 YBP 55 +/- 5 1954 +/- 5 A.D. -4 +/- 5 YBP aAges obtained from analysis in 2009 A.D. bCalendar years correction factor = │2009 - Blue OSL age│ cAge in years before present, referenced to the year 1950 A.D.
97
98
99
Figure 19. Sedimentation rates calculated from blue OSL ages OR-09-1 through OR-09-3 at location 09OR-5.
100
the depths of 162.7- to 147.3-cm. Sediment in this interval accumulated during the Agricultural
period at an average rate of 0.064-cm/yr, which is 191% faster than during the Pre-settlement
period. Above this, there was only a 50-year period between 142.5-cm depth and the top of the
section. These deposits accumulated during the Urbanization period at rate of 2.85-cm/yr, which is 4,353% faster than during the Agricultural period (Fig. 19).
At location 09OR-6, the sedimentation rates were computed using samples OR-09-4
through OR-09-6. Between depths of 211-cm and 207-cm, 4-cm of material accumulated over a
715 year period during Pre-settlement times. This is equivalent to a low sedimentation rate of
0.006-cm/yr (Fig. 20). Above this, at depths between 202.2-cm and 178-cm, 24.2-cm of material accumulated over 565 years. Sediment in this interval accumulated during the end of the Pre- settlement period and throughout the Agricultural period at a rate of 0.043-cm/yr, which is approximately 600% faster than the earlier rate (Fig. 20). Between 173.2-cm deep and the top of the section, the sediment accumulated over a 55-year period. These deposits accumulated during the Urbanization period at an average rate of 3.15-cm/yr, which is 7,225% faster than during the
Agricultural period (Fig. 20).
Overall, the Pre-settlement period had sedimentation rates of about 0.006-cm/yr. The overlying deposits from the Agricultural period had sedimentation rates between 0.022-cm/yr and 0.064-cm/yr (average of 0.043-cm/yr), which is an increase of approximately 600%. Above this, the clastic floodplain deposits representing the Urbanization period had sedimentation rates of 2.85-cm/yr to 3.15-cm/yr (average of 3.00-cm/yr), which is an average increase of approximately 6,900%. Also present in these clastic floodplain deposits were a number of human artifacts including pieces of rubber, tile, and a glass bottle. Based on the glass factory mark on the base of the bottle, it was determined that the bottle was made by the Owens-Illinois 101
Figure 20. Sedimentation rates calculated from blue OSL ages OR-09-4 through OR-09-6 at location 09OR-6.
102
Glass Company headquartered in Toledo, Ohio (Whitten, 2010). The number to the right of the
glass factory mark indicates the year the bottle was produced. For this bottle, the year was 1967.
This bottle was found stratigraphically above the historic flood horizon from 1959, which further
supports the blue OSL age. The other pieces of anthropogenic debris were also found above the
historic flood horizon and further support the deposition of these horizons during recent times.
Geochemical Analysis
The purpose of the geochemical analysis is to evaluate if the organic-rich horizons
represent hydromorphic soils. This study analyzed ten samples for major, Mg and Na, and trace
element, Cu, Mn, Pb, Sr, and Zn, concentrations. The concentrations obtained from the ICP-
OES were subsequently converted from mg/L to mg/kg of dry sample using Eqn. 14 (modified from U.S. Environmental Protection Agency, 2007).
S = (CICP*V)/W (Eqn. 14)
where S = sample concentration (mg/kg), CICP = concentration of the sample from the ICP-OES
(mg/L), V = volume of the sample solution (L), W = weight of the dry sediment (kg). The
volume of the sample solution was 0.05-L and the weight of the dry sediment was 0.0005-kg.
By inserting these values, a simplified version of Eqn. 14 could be determined.
S = 100*CICP (Eqn. 15)
As a result, each sample concentration from the ICP-OES was multiplied by 100 before being
reported in Table 16. The location and depth of each sample is noted in Figure 21.
At location 09OR-5, a number of distinct trends were observed in the peat layer
interpreted as a paleo-histosol (Fig. 22a-g). The concentration of Mg increases slightly, then 103
Table 16. Concentration of Elements with Depth at Three Locations Along the Ottawa River, OH. Sample No. Depthd Cu Mg Mn Na Pb Sr Zn 4a 145 2.02 1922 49.82 84.1 4.45 10.6 17.2 3a 175 3.35 2022 74.09 126.6 3.51 21.3 23.9 2a 183 4.96 1348 70.96 337.3 4.04 59.2 266.6 1a 190 7.69 13.92 247.2 213.3 4.16 41.5 37.9 10b 175 1.82 3912 43.13 113.0 2.21 11.4 8.8 9b 208 9.32 5197 95.43 205.4 21.46 139.1 50.5 8b 213 1.84 2497 39.98 89.8 4.14 13.5 16.4 15c 210 1.82 3912 43.13 113.0 2.21 11.4 8.8 14c 215 9.32 5197 95.43 205.4 21.46 139.1 50.5 13c 225 1.84 2497 39.98 89.8 4.14 13.5 16.4 These concentrations were measured using an ICP-OES and are reported in ppm. Each value was multiplied by 100 according to the equation S = (CICP*V)/W before being presented in this table. See text for further details. aSamples collected from location 09OR-5. bSamples collected from location 09OR-6. cSamples collected from location 09OR-12. dDepth is measured downward from the ground surface in cm.
104
105
106
decreases beginning at the peat layer and continuing with depth (Fig. 22a). The Mn
concentration increases above the peat layer, then decreases slightly between the overlying W layer and the peat layer, and finally increases dramatically below the peat layer (Fig. 22b). A general increase was seen in the concentration of Cu with depth (Fig. 22c). The amount of Pb decreases between the St and W facies above the peat layer (Fig. 22d). The Pb concentration then increases with depth. Most notably however, there is an enrichment of Na, Sr, and Zn in the peat layer (Fig. 22e-g).
At location 09OR-6, there is an interpreted paleo-inceptisol (poorly formed mineral soil).
The enrichment trend found in some of the elements at location 09OR-5 continues at this location (Fig. 23a-g). Here however, all elements displayed an enrichment pattern in the buried soil layer, Fmc. The Fmc layer marks the top of the organic floodplain facies assemblage (Fig.
21). These enrichments indicate that both the P and Fmc layers were subjected to processes that
concentrated the elements.
At location 09OR-12, there is not a buried soil. However, the same layer of massive sand with abundant wood debris (lithofacies W) is present. This site was studied as a control (non-
soil) to see the distribution of elements. The concentration of elements in the W layer was
examined relative to the layers above it (Fig. 24a-g). Mg, Na, and Pb concentrations decreased
between the overlying massive sand layer (Smc) and the W layer, while the Mn, Cu, Sr, and Zn concentrations increased. Considering the scale however, these variations are minimal compared to those seen at locations 09OR-5 and 09OR-6.
Overall, the interpreted paleo-histosol (P) and paleo-inceptisol (Fmc) layers were
compared to a non-paleosol of similar age and location. In the paleosol layers, a number of
107
108
109
element enrichments were found. The presence of a trend in these layers and a lack of such
trends in the non-paleosol support the interpretation of the P and Fmc layers as paleosols.
Sediment Budget
Calculation of Fill-Terrace Storage
Sediment budgets include the three main components of input, output, and storage (Eqn.
1). The amount of material in fill-terrace storage was examined to determine if it is reasonable
for a package of sediment averaging 158-cm thick to have accumulated over a period of only 21
years. To do so, the post-1959 package of material was investigated. Based on historical
changes in population and the effects of urbanization on fluvial systems, this package was
determined to have accumulated during the period of urbanization in the watershed which lasted
until 1980 (Fig. 7 and Wolman and Schick, 1967; Allmendinger et al., 2007). Therefore, the
volume of material in the fill-terraces was constrained to have accumulated over the 21-year
period from 1959 to 1980.
Both the vertical and lateral extent of the material in floodplain storage was calculated to
determine the total volume. The vertical extent is the average thickness of the upper package
which is found stratigraphically above the 1959 historic flood horizon (Table 7). The average
thickness of the fill-terrace package was calculated to be 158-cm (0.00158-km) based on the measurements at locations 09OR-5 and 09OR-6. The lateral extent, determined using topographic maps, was calculated to be 3.3 km2. The thickness was multiplied by the area to
give a total volume of 5.20*10-3-km3 in fill-terrace storage (Table 8).
110
Calculated Input (Soil Erosion)
The amount of input was calculated using a number of USLE values determined using
Eqn. 11 (Wischmeier and Smith, 1978).
A = R*K*LS*C*P (Eqn. 11)
The A value was determined by calculating the value of each of the five factors listed in Eqn. 11.
If data was absent, the factor was estimated using known values from other locations in the
watershed or from previous studies.
The R factor of 115.98 was calculated by adding the average erosion index of 112.5 and the value for thaw and snowmelt of 3.48 (Table 9a). The Rs value was equivalent to 1.5 times
the average precipitation in inches from December through March. These precipitation values
were 2.62, 2.00, 2.02, and 2.63, for an average of 2.32 (The Weather Channel, 2010). The R
factor of 115.98 was used throughout the watershed.
The average K factors for the counties were similar (Table 9b). In Fulton County, the
average was 0.32. In Lucas County, the average was 0.25. In Monroe County, the average was
0.27. K factor data was unknown for Lenawee County. Therefore, the average of 0.28 from the
other three counties was used.
The average LS factor was calculated for Fulton and Lucas Counties, and estimated for
Monroe and Lenawee Counties (Table 9c). Averages were obtained for the slope-length and
slope-gradient in each soil association. Based on these averages, an LS factor of 0.32 was found
for Fulton County and 0.27 for Lucas County. An average of 0.30 was used for Monroe and
Lenawee Counties.
For the agriculture-dominated counties of Fulton, Lenawee, and Monroe, a C factor of
0.48 was selected under the assumption of crop rotations between soybeans and corn (Natural 111
Resources Conservation Service, 2003). For Lucas County, two separate C factors were
estimated based on land use. In agricultural areas, the same C factor of 0.48 was used. In suburban areas, a value of 1.0 was selected (Table 9-3 in Fifield, 2004).
In agricultural areas, a P factor of 0.25 was estimated under the assumption that farmers
in the watershed implement contour strip cropping and the land slope is 2.0-7% (U.S. Soil
Conservation Service, 1975). The average gradient for the watershed was calculated to be 1.85%
(Table 9c), however 2.0-7% is valid approximation. In the suburban areas of Lucas County, a P
factor of 1.0 was used because these areas were likely covered with pavement, packed bare soil,
or sod grass (Fifield, 2004).
Based on the values calculated for these five factors, USLE values were obtained (Table
9d). For Fulton County, the soil erosion, or A value, is 1.4-tons/acre year-1. For Lenawee
County, the soil erosion is 1.2-tons/acre year-1. For Monroe County, the soil erosion is 1.1- tons/acre year-1. For Lucas County, two soil erosion values were calculated. For agricultural
areas, a soil erosion value of 0.94-tons/acre year-1 was calculated. For suburban areas, a value of
7.8-tons/acre year-1 was obtained (Table 9d). Using the above USLE values, the total average
amount of sediment produced from the upstream drainage basin was 2.5-tons/acre year-1 (Table
9e).
USLE Volume of Soil Eroded
The soil erosion values calculated using USLE were converted into volumes of sediment eroded over the 21-year Urbanization period in order to use the sediment budget equation (Table
9e). In the agricultural dominated counties of Fulton, Lenawee, and Monroe, the volumes eroded were 1.8*10-3-km3, 1.5*10-3-km3, and 1.4*10-3-km3. In Lucas County, the volume from 112
agricultural area was 1.2-km3 and the volume in the suburban area was 9.9*10-3-km3. Overall, the average total volume produced upstream was 3.2*10-3-km3.
Calculated Output
Sediment Budget Equation
The output was then calculated using the above volumes for input and storage (Table 10).
To do so, the sediment budget equation was rearranged to solve for output.
Input – Storage = Output (Eqn. 16)
where input is the average total volume produced upstream (km3), and storage is the volume of
material in fill-terrace storage (km3). Minimum and maximum values were selected for the
volume in storage because the 3-dimensional shape of the fill-terrace is unknown. As a result,
the maximum volume assumed the fill-terrace package was rectangular shaped, and the
minimum assumed it was wedge shaped. Based on these values, the total average output ranged
from -2.0*10-3-km3 to 0.60*10-3-km3 (Table 10).
Sediment Delivery Ratio
The output determined using the sediment budget equation was then checked
independently by examining the sediment delivery ratio (Eqn. 13 and Tables 11a and 11b).
Using the input from Table 9e and the output from Table 10, two sediment delivery ratios of
-63% and 19% were calculated (Eqn. 13). These values differ from the estimated sediment
delivery ratio of 8% based on the drainage basin size (Boyce, 1975). This estimated SDR was
used along with the calculated input (Table 9e) to determine an estimated output (Table 11b).
The estimated output value was 8% of the input, or 0.26*10-3-km3. The calculated input and 113 estimated output were then used to estimate the storage based on the sediment budget equation
(Eqn. 1 and Table 11b). By doing so, the volume in storage was estimated to be 2.9*10-3-km3. 114
DISCUSSION
Depositional Environments
Channel
The channel depositional environment includes sediment deposited in the stream channel.
These deposits are generally coarse-grained and include medium-grained sand to pebble-sized
gravel. The lithofacies formed in this environment include Gm, Se, Sl, Smc, Sp, St, Stf, Stl. The
Gm and Sp facies formed along the base of channel where gravel-sized sediment is transported
as bars and bed load sheets, while dunes form in the lower point bar, and there is a transition to
ripples in the upper point bar. Silt deposits (SSm and SSd) can also be deposited during low
flow velocity conditions. During elevated flow velocities, these bedforms can be replaced with
upper-flow-regime plane bed, such as lithofacies Sl.
Channel Margins
Lithofacies deposited along the margins of the channel include massive sand (Smc) that
may contain clay or silt lenses and wood debris (HdSSS, HdSFm) interbedded with massive clay to
massive silt (SSm, Fm, SSd) (Table 13). The deposition of these facies coincides with flooding.
The conveyance capacity of a river rises as discharge and stage height increase. As a result, the river picks up sediment, organic material, and debris. This combination of material can become mixed during transport. When the flood wanes, and the flow velocity decreases, the coarser- grained bed load is deposited. This sand-sized sediment can be rich in wood debris, leaf litter,
intraclasts, and lenses of finer-grained material as is seen in the HdSSS, HdSFm, and Smc facies. 115
As the energy continues to decrease, the suspended load is eventually deposited. Facies deposited under these conditions include SSm and Fm. Once this material is deposited, it is susceptible to erosion by subsequent flooding events. These events can scour into easily mobilized fine-grained material, as was the case with facies SSd.
Clastic Floodplains
In the clastic floodplain environment, sand, silt, and clay are deposited during flood events. As a result, deposits from in this area include thick packages of coarse-grained deposits
(Smc or HdSFm) interbedded with thin packages of fine-grained deposits (Fm or SSm). During periods when the rate of soil formation exceeds the rate of deposition, a soil can develop on the surface as seen in the modern floodplain (SSr). These soils are high in siliciclastic content, and are therefore considered mineral soils.
Organic Floodplains
In organic floodplains, a riparian wetland is present. These densely vegetated areas supply an abundant amount of organic debris. When the rate of soil formation exceeds the rate of sediment deposition in a wetland environment, organic soils (facies P) form. If the riparian wetlands are connected to the channel, during floods there could be periods of high clastic input and poorly formed, organic-rich mineral soils (facies Fmc) may form. Episodically, wetland environments can also experience higher-energy flooding events. During these periods, bed load composed of organic-rich sand with woody debris (lithofacies W and OS) is deposited followed by the suspended load of organic-rich clay with leaf litter (OFm).
116
Significance of Paleosols
It is important to determine if key horizons, such as the peat and carbonaceous mud layers, represent buried soils or paleosols. Evidence includes the presence of roots, peds, mottling, small concretions or nodules, root molds, and geochemical data. Specifically, if these layers are buried soils, they should show a distinct change in geochemistry with depth (Table 17
and Fig. 25a-g). Previous studies show that pre-settlement mineral soil profiles may contain an
A horizon above a weakly defined B horizon (Jacobson and Coleman, 1986). Figure 25a-g
shows the vertical distribution of elements in horizons A through C (Gregorauskiene and
Kadunas, 2006). By focusing solely on the transition from the A to B horizons, a variety of
trends can be found. Both Mg and Cu increase in concentration, Mn, Pb, and Zn decrease in
concentration, and Na and Sr remain approximately the same.
The results of the geochemical analysis in this study are somewhat inconsistent with
those of Gregorauskiene and Kadunas (2006). At location 09OR-5, the buried soil is a peat
layer, lithofacies P. Below this is a flood horizon, lithofacies W. The change in elemental
concentrations from facies P to facies W was examined and compared to the results in Figure
25a-g (Fig. 22a-g). In Fig. 25a-g, Mg and Cu increased, Mn, Pb, and Zn decreased, and Na and
Sr remained the same (Gregorauskiene and Kadunas, 2006). In Fig. 22a-g however, few of these
trends were observed. The concentration of Mg decreased while Cu increased. Mn increased,
Pb remained the same, and Zn decreased. The concentrations of Na and Sr both decreased.
Considering the sampled profile overall, the concentrations of Mg, Mn, Cu, and Pb in the peat
117
Table 17. Concentration of Elements with Depth in Lithuania.
Soil Cu Mg Mn Na Pb Sr Zn Horizon (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) Aa 7.8 3000 464 4300 19 82 254 Eb 6.7 3300 387 4400 15.8 80 235 Bc 11.4 5200 423 4200 15.8 83 191 Cd 11.7 9500 458 4200 14.9 97 191 (Modified from Gregorauskiene and Kadunas, 2006). Concentrations are the average value obtained for each soil horizon and include different soil textures. an = 53 bn = 43 cn = 52 dn = 53
118
119
layer were similar to trend of the surrounding layers while Na, Sr, and Zn all showed a distinct enrichment in the peat layer.
At location 09OR-6, the buried soil is a carbonaceous mud layer, lithofacies Fmc. Below
this horizon is the same massive sand layer, lithofacies W, seen at location 09OR-5. The
transition from Fmc to W again showed inconsistent results with the previous study (Fig. 23a-g).
All elements decreased in concentration between these two depths, when only Mn, Pb, and Zn
decreased in a previous analysis (Gregorauskiene and Kadunas, 2006). However, the profile as a
whole shows a trend of enrichment in the buried soil layer, Fmc, similar to that seen at location
09OR-5 with Na, Sr, and Zn.
The variations seen at location 09OR-12 between layer W and the overlying deposits are
minimal in comparison to those found at the other locations. For instance, the Sr concentration in layer W is an average of 7.84-ppm higher than the adjacent deposits at location 09OR-12, but the concentration averages 126.6-ppm higher at 09OR-6 and 34.75-ppm higher at 09OR-5.
Thus, comparatively speaking, the W layer at 09OR-12 lacks any noticeable depletion or enrichment. This lack of variation was anticipated because these layers are alluvial deposits which should not show enrichments. If the layer was a soil however, it would be subjected to the
secondary process of pedogenesis whereby elements are redistributed to take on a distinct trend.
Therefore, the lack of trends at location 09OR-12 supports the interpretation of layer W as a
flood horizon.
There were distinct trends however, at locations 09OR-5 and 09OR-6. The carbonaceous
mud layer at location 09OR-6 was enriched in all elements, and the peat layer at location 09OR-
5 was enriched in Na, Sr, and Zn. These trends indicate that the mud and peat layers are, in fact,
buried soils that were subjected to pedogenesis. 120
The differences between the trends found in this study and other studies (ex.
Gregorauskiene and Kadunas, 2006), are likely the result of the spacing between samples. If samples were collected using a higher resolution, it may have been possible to locate the trends indicative of the A and B horizons. As it were, these trends were not decipherable.
Alluvial Stratigraphy
The alluvial stratigraphy indicates four different time intervals represented by lithofacies and geochronology. Starting at the base, these packages include (1) > 5 Ka point bar deposits,
(2) ~5 Ka to ~400 YBP organic floodplain deposits, (3) ~400 to -9 YBP channel and channel margin deposits, and (4) post-1959 clastic floodplain deposits. The lower package of channel and channel margin deposits and is almost entirely lacking of organic material (Fig. 17). It is composed of interbedded massive silts and massive sands indicative of flooding. While specific dates for this package are unknown, radiocarbon dates of overlying deposits indicate these layers must have formed prior to 4889 +/- 178 YBP. The lack of organic debris also suggests that these layers were in place before the establishment of the Great Black Swamp when such debris would have been abundant. As such, they represent fluvial deposits, specifically point bar deposits formed through lateral accretion.
Further up section, there is a dramatic shift in lithology and organic content (Fig.
15). This package of material includes deposits formed in an organic floodplain. It contains sand and clay that are heavily laden with organic material including wood debris and leaf litter.
Also present are a series of histosols and hydromorphic paleosols. Dates for this package include radiocarbon ages of 4889 +/- 178 YBP, 4731 +/- 306 YBP, 4547 +/- 326 YBP, and 82.5 +/- 121 121
YBP, and blue OSL ages of 1276 +/- 80 YBP, 561 +/- 55 YBP, and 421 +/- 40 YBP. As
previously discussed, the one discordant 14C age is discounted because it is likely the result of
contamination (scouring and deposition of wood from recent flooding). The other six ages and
types of deposits are consistent with deposition of this package during the Pre-settlement period
when the Great Black Swamp dominated the watershed (Wilhelm, 1984). The fluvial system in
this environment consisted of a lateral accretion regime as evidenced by the low sedimentation
rate of 0.006-cm/yr during the Pre-settlement period. The presence of buried soils indicates that
the landscape was historically stable enough to support soil formation at this time interval.
Overlying the organic floodplain deposits are channel and channel margin deposits 33-cm
to 68-cm thick (Fig. 15). At locations 09OR-12 and 09OR-5, the channel margin deposits
consist of massive sand (Smc) interbedded with massive or discontinuous silt (SSm or SSd).
This package is topped with the historic flood horizon. At location 09OR-6, the channel deposits include trough cross-bedded sands (St, Stl) interbedded with discontinuous silt (SSd). One blue
OSL age of 231 +/- 15 YBP was obtained for this package which approaches the initial period of
land clearance in northwest Ohio (early- to mid-1800s). The sedimentation rates of this interval
are an order of magnitude higher than the lower layers (between 0.022-cm/yr and 0.064-cm/yr).
The combination of interbedded clastic sediment from flooding (flood rhythmites) and organic
deposits (riparian wetland) along with the age suggest the initial shift to vertical accretion during
the Agricultural period in this region.
The prominent 13-cm to 32.5-cm trough cross-bedded sand layer was laterally correlated
across the study area (Fig. 15). Two blue OSL ages of -9 +/- 5 YBP and -4 +/- 5 YBP where
obtained for this horizon. The ages and composition indicate this layer represents deposits from
a flood that occurred in the area in January 1959. Historically, this was one of the major floods 122 on record. At the Toledo Airport, a reported 3.68-cm of rain fell on frozen ground (Toledo
Blade, 1959). The frozen ground acted as an impervious surface which allowed for all of the precipitation to act as runoff and channelize into the fluvial system. As a result, the stage height increased dramatically. The Monroe Street bridge was covered with 15-cm of water, approximately 3.5-km downstream of the study area (Toledo Blade, 1959).
Overlying this historic flood horizon is an upper package of 1.4- to 1.7-cm thick clastic floodplain deposits (Fig. 15). The composition includes interbedded sands and clays topped with the silty modern soil. Based on the OSL dates of the historic flood horizon, this package of material has accumulated over the past 50 years which corresponds to a sedimentation rate of
2.85- to 3.15-cm/yr. This interval represents a drastic period of vertical accretion and corresponds to the Urbanization period in the region.
Alluvial Stratigraphy and Land Use Changes
The shifts in lithology and sedimentation rates correspond with land use changes in watershed. Previous studies have correlated similar shifts with three main phases of land use:
Pre-settlement, Agricultural, and Very Recent (erosional) (Jacobson and Coleman, 1986;
Allmendinger et al., 2007; Walter and Merritts, 2008). In this study, four main phases of land use were discovered: Pre-settlement, Agricultural, Urbanization, and Very Recent.
In addition, for this region two distinct Pre-settlement periods were observed. Prior to 5-
Ka, the fluvial environment was dominated by lateral accretion and mixed sediment loads.
Deposits formed in organic-poor channels, point bars, and floodplains. Then, as Lake Erie rose to its present level around 5-Ka, reduced stream gradients resulted in the formation of estuaries 123
and the Great Black Swamp. A densely vegetated landscape coincided with low sedimentation
rates of 0.006-cm/yr and the establishment of wetland soils. These later Pre-settlement
conditions were similar to those found on the east coast during pre-settlement times. However,
sedimentation rates in Ohio were markedly lower than those found in places like Chesapeake
Bay, where pre-settlement rates were closer to 0.1-cm/yr (Pasternack et al., 2001). Yet, the
deposits were similar to those found in previous studies and include organic-rich clays and sands
with a series of hydromorphic paleosols.
Above the organic floodplain are deposits which accumulated in during a transition to
bed load-dominated streams between approximately 500 – 200 YBP. The channel and channel margin deposits are thicker and coarser-grained than those from > 4-Ka. They correspond to formation in shallower channels. Sedimentation rates were on the order of 0.022-cm/yr.
Following this period was the initiation of agricultural land use. The Agricultural period began when the Great Black Swamp was drained in the mid- to late-1800s (Fig. 7). Agricultural
land use peaked in 1900 and has generally declined since then. During this period,
sedimentation rates in the Ottawa River watershed nearly tripled from 0.022-cm/yr to an average
of 0.064-cm/yr (Fig. 19). The increase was the result of a higher runoff rate and sediment supply
associated with deforestation of the watershed (Costa, 1975; Jacobson and Coleman, 1986).
Floodplain aggradation was present, but the signature was lower than other areas in the United
States (Jacobson and Coleman, 1986; Allmendinger et al., 2007; Walter and Merritts, 2008).
The Urbanization period represents the 1.4- to 1.7-m thick clastic floodplain deposits that formed since 1959. Between the 1950s and 1970s, the populations of the main suburban areas upstream of the study area saw the greatest increases in their history (Table 2). The populations of Sylvania Township and the city of Sylvania nearly doubled every decade (Table 2). 124
Coincident with these increases in population, is an increase in land clearance from housing
construction.
In parts of Maryland, it was shown that for every 1000 increase in population, there was a
sediment yield of 700-1800 metric tons due to construction (Wolman and Schick, 1967).
Without management practices, the values could reach from 200- to 55,000-metric tons/km2
year-1. This high degree of sediment loading and runoff in an urbanized drainage system can
quickly overload a river. Floodplains, and other storage areas, aggrade as sediment is deposited.
Along the Ottawa River, the impact of construction is evident in the alluvial stratigraphy.
Sedimentation rates soared from an average of 0.043-cm/yr during the Agricultural period to an
average of 3.0-cm/yr during suburbanization (Fig. 18). The only source of such a large amount
of sediment over such a short period of time is construction. At these sites, erosion can remove
the same amount of sediment in one year that would take natural and agricultural areas decades
(Wolman and Schick, 1967).
In contrast to the continued soil erosion input of agricultural development, this dramatic
increase in sediment supply from housing construction is relatively short-lived (Wolman and
Schick, 1967). Housing developments represent a short-term sediment pulse because the
housing developments are re-vegetated, thereby reducing the supply of sediment. However, the
urbanized drainage system is still in place which acts to quickly channelize runoff into rivers
(Baker et al., 2004). The now sediment-depleted water has a higher conveyance capacity and
picks up additional sediment load from storage.
In the Ottawa River, this process is visible as the anthropogenic terraces are subjected to
erosion. This corresponds to the Very Recent period from the East Coast, but has a different
cause. On the East Coast, the erosion was due to agricultural land abandonment and re- 125
vegetation (Costa, 1975; Jacobson and Coleman, 1986; Walter and Merritts, 2008). For the
Ottawa River, these most recent conditions are creating a new, lower elevation floodplain (Fig.
26). The fluvial system has shifted from vertical accretion during the agricultural and
suburbanization periods back to lateral accretion, as seen in the Pre-settlement period.
Sediment Budget
The volume of material in storage was calculated using the thickness of material above
the historic flood horizon which was estimated to have accumulated between 1959 and 1980.
During this period, the population boom resulted in increased rates of construction (Fig. 8),
which likely generated high amounts of sediment-rich runoff (Wolman and Schick, 1967).
Erosion Rates (Input) Determined Using USLE
The calculated USLE values were similar for the counties of Fulton, Lenawee, and
Monroe at 1.4-tons/acre year-1, 1.2-tons/acre year-1, and 1.1-tons/acre year-1 respectively (Table
9d). For Lenawee County, this could be partially due to the paucity of data, which necessitated the use of averages for most of the factors. However, the minimal variation found between the factors in each county suggests these were logical assumptions. In Lucas County, two soil erosion values were calculated including 0.94-tons/acre year-1 in the agricultural area and 7.8-
tons/acre year-1 in the suburban area (Table 9d). Throughout the watershed, the only factors that
saw considerable fluctuations were the C and P factors in suburban area of Lucas County. In
Fulton, Lenawee, and Monroe County, the land use is predominately agricultural. Therefore, the 126
Figure 26. Example of the anthropogenic terraces resulting from suburbanization, as well as the lower elevation floodplains from a decrease in sediment supply following a re-vegetation of the landscape in the Ottawa River watershed.
127
similar USLE values were expected and calculated in these areas as well as in the agricultural
part of Lucas County.
In the suburban area of Lucas County, the input was 550% higher at 7.8-tons/acre year-1.
This high rate of erosion is present in the suburban area of the watershed which accounts for only
16% of the total area. The average soil erosion rate of 1.2-tons/acre year-1 is present in the
remaining 84% which is comprised of agricultural land. This relationship is similar to that found
in the Patuxent River, where urbanized areas account for 23% of the drainage basin, but
contribute 82% of the suspended sediment load (Roberts and Pierce, 1974).
The volume of input over 21-years was also calculated (Table 9e). For the agricultural
areas, similar volumes were found including 1.2-km3, 1.4-km3, 1.5-km3, and 1.8-km3 with an
average of 1.5-km3. In the suburban area, the volume was 560% higher at 9.9-km3.
Output Determined Using Sediment Budget Equation
The amount of material in fill-terrace storage was also calculated (Table 8). Based on
differences in geometry, the volume in fill-terrace storage was determined to range from 2.6*10-
3-km3 to 5.2*10-3-km3. These storage volumes were then inserted into the sediment budget equation along with the calculated input volumes (Table 10). By doing so, output volumes were obtained of 0.60*10-3-km3 for a wedge shaped package, and -2.0*10-3-km3 for a rectangular shaped package.
A negative output would indicate that the amount of material in storage is decreasing
through erosion. However, the period of 1959-1980 was a time of abundant population growth
and construction (Fig. 8), which coincide with increased rates of sediment supply and runoff
(Leopold and Skibitzke, 1967; Hollis, 1975; Sauer et al., 1983; Roberts and Pierce, 1974). These 128
studies indicate that the amount of material in storage increases during urbanization. Therefore, the volume of material in storage is likely closer to the shape of a wedge (volume of 0.60*10-3- km3) than a rectangle (volume of -2.0*10-3-km3).
The output of 0.60*10-3-km3 is equivalent to a sediment yield of 106-t/km2 year-1. This
value is similar to the 135-t/km2 year-1 calculated in the urbanizing watershed of the Good Hope
Tributary (MD) (Allmendinger et al., 2007). It is much lower than the several thousand t/km2 year-1 found on construction sites in Maryland (Wolman and Schick, 1967). These discrepancies
likely result from the variation of land uses in the Ottawa River watershed, which is dominated
by 84% agricultural land upstream of the study area. If more than 16% of the watershed had
been converted to suburban land, the sediment yield would have likely been much higher. The
lower sediment yield could also be accounted for by changes in the amount of construction.
Allmendinger et al. (2007) reported short periods of abundant construction followed by longer
periods of minimal construction. If a similar pattern is inferred for the Ottawa River watershed,
then these fluctuations would coincide with changing sediment yields rather than a consistent
sediment yield. Therefore, the calculated sediment of 106-t/km2 year-1 can be interpreted as an
average value. The true value likely ranged dramatically from hundreds to thousands during
construction periods to approximately 10-t/km2 year-1 during construction quiescence
(Allmendinger et al., 2007).
Output Determined Using Sediment Delivery Ratio
A final check of the output was conducted using the sediment delivery ratio. This ratio
was calculated using the output volume from the sediment budget equation and the input volume
from USLE (Table 11a). Two ratios of -65% and 19% were found based on the geometry of the 129
fill-terrace. The negative sediment delivery ratio coincided with a rectangular geometry, which
further discounts this shape as the true fill-terrace geometry. For comparison, an independent
sediment delivery ratio of 8% was determined based on the drainage basin size (Table 11b and
Boyce, 1975). This SDR is similar to the 19% ratio obtained under the assumption of a wedge
shaped fill-terrace. Estimates were also made for the output volume of 0.26*10-3-km3 and the
storage volume of 2.9*10-3-km3 (Table 11b). The calculated output of 0.60*10-3-km3 is
approximately 130% higher than the estimated volume, but the calculated storage of 2.6*10-3- km3 is only 12% lower than the estimated storage volume of 2.9*10-3-km3.
These similarities indicate that the assumptions made for the input and storage were reasonable. While the accumulation of an average of 158-cm over 21 years seems unlikely, the high sediment yields calculated above support this interpretation.
130
CONCLUSIONS
A series of deposits were correlated across the study area (Fig. 15). Changes in the lithology and sedimentation rates of these packages were found to coincide with changes in land use. The lower package consists of channel and channel margin deposits with interbedded massive silts and massive sands that accumulated during the Pre-settlement period (prior to 5-
Ka). The composition and inferred ages of this package indicate formation during the Pre- settlement period when lateral accretion resulted in point bar deposits.
As Lake Erie rose to its present level (~ 5-Ka), the Great Black Swamp formed in the watershed. Consequently, material from this period includes organic floodplain deposits with abundant wood debris and leaf litter. These deposits accumulated at a rate of 0.006-cm/yr.
Radiocarbon ages of the organic floodplain deposits include 4889 +/- 178 YBP, 4731 +/- 306
YBP, 4547 +/- 326 YBP, and 82.5 +/- 121 YBP. Blue OSL ages for this package are 1276 +/- 80
YBP, 561 +/- 55 YBP, and 421 +/- 40 YBP. These ages place both the organic floodplain and underlying channel and channel margin deposits at an age of deposition prior to European settlement in the mid-1800s. The geochemistry of two suspected buried soil horizons and a flood deposit in the organic floodplain deposits was also examined. The soils showed a distinct pattern of enrichment relative to the adjacent deposits, while the flood horizon lacked such variability.
Above the organic floodplain deposits is a return to channel and channel margin deposits.
These layers were deposited during the transition from swamp conditions to broad, shallow, coarse-grained channel conditions (200-500 YBP). One blue OSL date places the deposits at an age of 231 +/- 15 YBP. Sedimentation rates for this material increased an order of magnitude to
0.022-cm/yr. As agricultural land use increased between 231 +/- 15 YBP and -9 +/- 5 YBP, the 131
sedimentation rate tripled to 0.064-cm/yr. Above the Agricultural period deposits is a
particularly prominent layer of trough cross-bedded, well rounded, moderately well sorted,
medium- to coarse-grained sand that was correlated across the study area. It was dated to -4 +/-
5 YBP and -9 +/- 5 YBP with blue OSL and was interpreted to represent deposits from a
historical flood in 1959.
Overlying this layer, are 1.4-m to 1.7-m thick clastic floodplain deposits. The OSL dates
of the underlying historic flood layer reveal that these clastic floodplain deposits have
accumulated within the last 50 years. However, based on the history of land use and population
growth, it was further concluded that these deposits were formed during the Urbanization period
from 1959-1980. This period included dramatic population increases upstream of the study area.
As a result, large amounts of sediment were brought into the fluvial system (106-t/km2 year-1).
The accumulation rate of this package was calculated at 3.0-cm/yr.
In order to test these interpretations, a sediment budget model was created. Input was
calculated from USLE. Soil erosion rates ranged from 0.94- tons/acre year-1 to 1.4-tons/acre
year-1 in agriculture-dominated areas, and 7.8-tons/acre year-1 in the suburban portion of Lucas
County. Volume of sediment produced from these areas averaged 3.2*10-3-km3. The volume of
input was then compared to the volume in fill-terrace storage which was calculated based on the
stratigraphy and geochronology data. This package was interpreted to have accumulated
between 1959 and 1980. The total volume in the fill-terrace package was found to be
approximately 2.6*10-3-km3. Using these input and storage values, the volume of output was
calculated to be 0.60*10-3-km3. To independently check the output, the sediment delivery ratio equation was implemented. The ratio was found to be 19%, which is comparable to the 8% 132 found based on the drainage basin size (Boyce, 1975). These findings indicate that the accumulation of an average of 158-cm over a 21-year span is reasonable.
Following this period, the landscape became re-vegetated, the sediment supply decreased, but runoff remained elevated as a result of an urbanized drainage system. The conveyance capacity of the fluvial system increased, and sediment in storage was remobilized. Through this process of erosion and incision, a new lower elevation floodplain is being established. The
Ottawa River will continue to erode into the anthropogenic terraces as it attempts to return to a lateral migration regime similar to that of pre-settlement conditions.
133
REFERENCES
Allmendinger, N.E., J.E. Pizzuto, G.E. Moglen, and M. Lewicki, 2007. A sediment budget for an urbanizing watershed, 1951-1996, Montgomery County, Maryland, USA. Journal of the American Water Resources Association, 43(6): 1483 – 1498.
Anttila, P.W. and R.L. Tobin, 1976. Fluvial sediment in Ohio. U.S. Geological Survey Open File Report 76-575, 152 p.
Attendorn, H.-G. and R.N.C. Bowen, 1997. Radioactive and Stable Isotope Geology. Chapman & Hall, New York, p. 244-250.
Baker, D.B., R.P. Richards, T.T. Loftus, and J.W. Kramer, 2004. A new flashiness index: Characteristics and applications to Midwestern rivers and streams. Journal of the American Water Resources Association, 40(2): 503-522.
Beighley, R.E. and G.E. Moglen, 2002. Assessment of stationarity in rainfall-runoff behavior in urbanizing watersheds. Journal of Hydrologic Engineering, ASCE, 7(1): 27- 34.
Black Swamp Conservancy. Accessed 14 Apr 2009. http://www.blackswamp.org/
Bosch, J.M. and J.D. Hewlett, 1982. A review of catchment experiments to determine the effect of vegetation changes on water yield and evapotranspiration, in Jacobson, R. B., and D.J. Coleman, 1986. Stratigraphy and recent evolution of Maryland Piedmont floodplains. American Journal of Science, 286: 617-637.
Bøtter-Jensen, L.S., W.S. McKeever, and A.G. Wintle, 2003. Optically Stimulated Luminescence Dosimetry. Elsevier Science B.V., Amsterdam, p. 1.
Boyce, R.C., 1975. Sediment routing with sediment delivery ratios, in USDA Agricultural Research Service, Present and prospective technology for predicting sediment yields and sources. Publication ARS-S40, p. 61-65.
Brune, G.M., 1948. Rates of sediment production in the Midwestern United States. Soil Conservation Service Technical Report 65, U.S. Government Printing Office, Washington, D.C., 40 p.
Camp, M.J., 2006. Roadside Geology of Ohio. Mountain Press Publishing Company, Missoula, p. 35-52.
Carter, R.W., 1961. Magnitude and frequency of floods in suburban areas. U.S. Geological Survey Professional Paper 424-B, p. B9-B11.
134
Clark, A., 2008. Lake Erie Holocene coastal evolution near the Portage River – Catawba Island, Ohio [M.S. Thesis]: Bowling Green, Bowling Green State University, 224 p.
Coogan, A.H., 1996. Ohio’s surface rocks and sediments, in Feldman, R.M. and M. Hackathorne, ed., Fossils of Ohio: Ohio Division of Geological Survey Bulletin, 70: 31- 50.
Costa, J.E., 1975. Effects of agriculture on erosion and sedimentation in the Piedmont Province, Maryland. Geological Society of America Bulletin, 86: 1281-1286
Dickin, A.P., 1995. Radiogenic Isotope Geology. Cambridge University Press, New York, p. 360-372.
Evans, J.E. and N. Harris, 2008. Preliminary study of the sediment impacts of the 2007 removal of the Secor dam (Ottawa River, Ohio). Conference Proceedings, 16th National Nonpoint Source Monitoring Workshop, U.S. Environmental Protection Agency/Ohio Environmental Protection Agency/Ohio State University Extension, Columbus, Ohio, September 14-18, 2008, p. 57-58.
Evans, J.E., J.F. Gottgens, W.M. Gill, and S.D. Mackey, 2000. Sediment yields controlled by intrabasinal storage and sediment conveyance over the interval 1842-1994: Chagrin River, Northeast Ohio, U.S.A. Journal of Soil and Water Conservation, Third Quarter.
Faulkner, D. and S. McIntyre, 1996. Persisting sediment yields and sediment delivery changes. Water Resources Bulletin, 32(4): 817-829.
Faure, G., 1977. Principles of Isotope Geology. John Wiley & Sons, Inc., New York, p. 306-307.
Faure, G. and T.M. Mensing, 2005. Isotopes: Principles and Applications. 3rd ed. John Wiley & Sons, Inc., New Jersey, p. 614.
Fifield, J.S., 2004. Designing for Effective Sediment and Erosion Control on Construction Sites. 2nd ed. ForesterPress, Santa Barbara, 336 p.
Forsyth, J.L., 1960. The beach ridges of northern Ohio, in Toledo Metropolitan Area Council of Governments, 2008. TMACOG areawide water quality management plan. http://www.tmacog.org/Environment/208currentplan/TMACOG_AWQMP.pdf
Forsyth, J.L., 1968. A study of the physical features for the Toledo regional area. The Toledo Regional Area Plan for Action, Regional Report (8.2): 1-111.
Gallagher, R.E., 1978. Ottawa River (Tenmile Creek) hydrology: stream flow quantity and erosion at Toledo, Ohio [M.S. Thesis]: Toledo, University of Toledo, 187 p.
135
Gerwin, K., 2003. Land-use change in the Ottawa River watershed. http://www.utoledo.edu/as/geography/pdfs/research_gerwin2.pdf
Gregorauskiene, V. and V. Kadunas, 2006. Vertical distribution patterns of trace and major within soil profile in Lithuania. Geological Quarterly, 50(2): 229-237.
Guy, H.P. and V.W. Norman, 1970. Field methods for measurement of fluvial sediment. Techniques of Water Resources Investigations of the United States Geological Survey, book 5, p. 59.
Haan, C.T., B.J. Barfield, and J.C. Hayes, 1994. Design Hydrology and Sedimentology for Small Catchments. Academic Press, San Diego, p. 264.
Harris, N., 2008. Sedimentological response of the 2007 removal of a low-head dam, Ottawa River, Toledo, Ohio [M.S. Thesis]: Bowling Green, Bowling Green State University, 228 p.
Hollis, G.E., 1975. The effect of urbanization on floods of different recurrence interval, in Allmendinger, N.E., J.E. Pizzuto, G.E. Moglen, and M. Lewicki, 2007. A sediment budget for an urbanizing watershed, 1951-1996, Montgomery County, Maryland, USA. Journal of the American Water Resources Association, 43(6): 1483 – 1498.
Jackson, J.A., Ed., 1997. Glossary of Geology. 4th ed. American Geological Institute, Alexandria, 769 p.
Jacobson, R.B. and D.J. Coleman, 1986. Stratigraphy and recent evolution of Maryland Piedmont floodplains. American Journal of Science, 286: 617-637.
Kinney, K. 1999. Black Swamp once ruled the land and people. Bowling Green Sentinel Tribune.
Kuhnle, R.A., R.L. Bingner, G.R. Foster, and E.H. Grissinger, 1996. Effect of land use changes on sediment transport in Goodwin Creek. Water Resources Research, 32(10): 3189-3196.
Larson, G. and R. Schaetzl, 2001. Origin and evolution of the Great Lakes. International Association of Great Lakes Research, 27: 518-546.
Leopold, L.B., 1956. Land use and sediment yield, in W.L. Thomas, ed., Man’s Role in Changing the Face of the Earth. University of Chicago Press, Chicago, p. 639-647.
Leopold, L.B. and H.R. Skibitzke, 1967. Observations on unmeasured rivers, in Allmendinger, N.E., J.E. Pizzuto, G.E. Moglen, and M. Lewicki, 2007. A sediment budget for an urbanizing watershed, 1951-1996, Montgomery County, Maryland, USA. Journal of the American Water Resources Association, 43(6): 1483 – 1498.
136
Leverett, F. and F.B. Taylor, 1915. The Pleistocene of Indiana and Michigan and the history of the Great Lakes. U.S. Geological Survey Monograph, vol. 53.
Li, B., S-H. Li, and A.G. Wintle, 2008. Overcoming environmental dose rate changes in luminescence dating of waterlain deposits. Geochronometria, 30: 33-40.
Lian, O.B., 2007. Optically-Stimulated Luminescence. Encyclopedia of Quarternary Science. Elsevier Science B.V., Amsterdam, p. 1491-1505.
Libby, W.F., 1955. Radiocarbon Dating. 2nd ed. University of Chicago Press, Chicago, p. 34-36.
Lu, H., C.J. Moran, and I.P. Prosser, 2006. Modelling sediment delivery ratio over the Murray Darling Basin. Environmental Modelling & Software, 21(9): 1297-1308.
Mannik-Smith Group, Inc., 2008. Ottawa River habitat restoration inventory. http://www.tmacog.org/Environment/Ottawa_River_Habitat/Ottawa_River_Habitat_Rest oration_Inventory.pdf
Martin, A., J.T. Gunter, and J.L. Regens, 2003. Estimating erosion in a riverine watershed. Environmental Science & Pollution Research, 10(4): 245-250.
Murray, A.S. and A.G. Wintle, 2000. Luminescence dating of quartz using an improved single-aliquot regenerative-dose protocol. Radiation Measurements, 32: 57-73.
Norris, S.E., 1975. Geologic structure of near-surface rocks in western Ohio. Ohio Journal of Science, 75(5): 225-228.
Natural Resources Conservation Service, 2003. Chapter 19: Universal Soil Loss Equation. Natural Resources Inventory, p. 19-2. ftp://ftp- fc.sc.egov.usda.gov/NCGC/products/nri/2003nri/nri03ch19.pdf
Palmer, M.A., G.E. Moglen, N.E. Bockstael, S. Brooke, J.E. Pizzuto, C. Wiegand, and K. van Ness, 2002. The ecological consequences of changing land use for running waters: The suburban Maryland case. Yale Forestry and Environmental Science Bulletin, 107: 85-113.
Pasternack, G.B., G.S. Brush, and W.B. Hilgartner, 2001. Impact of historic land-use change on sediment delivery to a Chesapeake Bay subestuarine delta. Earth Surface Processes and Landforms, 26(4): 409-427.
Power, M.S. and T.L. Holzer, 1996. Liquefaction Maps. Applied Technology Council TechBrief, 12 p.
Rittenour, T.M., 2008. Luminescence dating of fluvial deposits: applications to geomorphic, palaeoseismic and archaeological research. Boreas, 37: 613-635.
137
Roberts, S.J., J.F. Gottgens, A.L. Spongberg, J.E. Evans, and N.S. Levine, 2007. Assessing potential removal of low-head dams in urban settings: An example from the Ottawa River, NW Ohio. Environmental Management, 39: 113-124.
Roberts, W.P. and J.W. Pierce, 1974. Sediment yield in the Patuxent River (Maryland) undergoing urbanization, 1968-1969. Sedimentary Geology: 12(3): 179-197.
Sauer, V.B., W.O. Thomas, Jr., V.A. Stricker, and K.V. Wilson, 1983. Flood characteristics of urban watershed in the United States, in Allmendinger, N.E., J.E. Pizzuto, G.E. Moglen, and M. Lewicki, 2007. A sediment budget for an urbanizing watershed, 1951-1996, Montgomery County, Maryland, USA. Journal of the American Water Resources Association, 43(6): 1483 – 1498.
Schacklette, H.T. and J.G. Boerngen, 1984. Element concentrations in soils and other surficial materials of the conterminous United States. U.S. Geological Survey Professional Paper 1270, U.S. Government Printing Office, Washington D.C., 63 p.
The Weather Channel, 2010. Monthly Averages for Toledo, OH. http://www.weather.com/outlook/health/allergies/wxclimatology/monthly/graph/USOH0 953.
Toledo Blade, 21 Jan. 1959. "Schools Closed, Traffic Snarled, Power Lines Broken In Toledo As Giant Storm Hits Most of U.S." p. 1+. Print.
Toledo Blade, 4 Feb. 1960. “Bedford Township Real Estate Boom Continues; Subdivisions Mount to Millions of Dollars Value.” p. 10. Print.
Toledo Regional Area Plan for Action, 1970. Urbanization in the Toledo Regional Area: A Historical Review, Regional Report (10.4): 1-51.
Trimble, S.W., 1983. A sediment budget for Coon Creek Basin in the Driftless Area, Wisconsin, 1853-1977. American Journal of Science, 283: 454-474.
U.S. Census of Population, 1890-2000. Summary population and housing characteristics. U.S. Department of Commerce.
USDA, 1980. Soil Survey of Lucas County, Ohio. http://soildatamart.nrcs.usda.gov/manuscripts/OH095/0/lucas.pdf. 150 p.
USDA, 1981. Soil Survey of Monroe County, Michigan. http://soildatamart.nrcs.usda.gov/manuscripts/MI115/0/monroe.pdf. 149 p.
USDA, 1984. Soil Survey of Fulton County, Ohio. http://soildatamart.nrcs.usda.gov/manuscripts/OH051/0/fulton.pdf. 177 p.
138
USDA NRCS, 2004. Field Office Technical Guide. http://efotg.nrcs.usda.gov/efotg_locator.aspx?map=OH
USDA NRCS, 2010. Field Office Technical Guide. http://efotg.nrcs.usda.gov/efotg_locator.aspx?map=MI
U.S. Environmental Protection Agency, 2007. Test methods for evaluating solid waste, physical/chemical methods. Office of Resource Conservation and Recovery, Washington, D.C.
U.S. Soil Conservation Service, 1975. Procedure for computing sheet and rill erosion on project areas. Technical Release No. 51, Washington, D.C., p. 15. in Dunne, T. and Leopold, L. B., 1978. Water in Environmental Planning. W.H. Freeman and Company, New York, p. 529-530.
Walter, R.C. and J. Merritts, 2008. Natural Streams and the Legacy of Water-Powered Mills. Science, 319: 299-304.
Whiting, P.J., W.E. Dietrich, L.B. Leopold, T.G. Drake, and R.L. Shreve, 1988. Bedload sheets in heterogeneous sediment. Geology, 16(2): 105-108.
Whitten, D., 2010. Glass Factory Marks on Bottles. http://www.myinsulators.com/glass- factories/bottlemarks.html
Wilhelm, P.W. 1984. Draining the Black Swamp: Henry and Wood Counties, Ohio, 1870-1920. Northwest Ohio Quarterly, 56(3): 79-95.
Wischmeier, W.H. and D.D. Smith, 1978. Predicting rainfall erosion losses: A guide to conservation planning. U.S. Department of Agriculture, Agriculture Handbook No. 537, 63 p.
Wolman, M.G., 1967. A cycle of sedimentation and erosion in urban river channels. Geograpfiska Annaler, Series A: Physical Geography, 49(2/4): 385-395.
Wolman, M.G. and A.P. Schick, 1967. Effects of construction on fluvial sediment, urban and suburban areas of Maryland. Water Resources Research, 3(2): 451-464.
139
APPENDICES 140
APPENDIX A
STRATIGRAPHIC SECTIONS 141
Figure A-1: Stratigraphic section at location 09OR-1. 142
Figure A-2: Stratigraphic section at location 09OR-2. 143
Figure A-3: Stratigraphic section at location 09OR-3. 144
Figure A-4: Stratigraphic section at location 09OR-4. 145
Figure A-5: Stratigraphic section at location 09OR-5. 146
Figure A-6: Stratigraphic section at location 09OR-6. 147
Figure A-7: Stratigraphic section at location 09OR-7. 148
Figure A-8: Stratigraphic section at location 09OR-8.
149
Figure A-9: Stratigraphic section at location 09OR-10. 150
Figure A-10: Stratigraphic section at location 09OR-11. 151
Figure A-11: Stratigraphic section at location 09OR-12. 152
APPENDIX B
GRAIN SIZE ANALYSIS 153
Table B-1. Totals and Percentages of Grain Sizes. Sample Sand Silt Clay Totala Sandb Siltc Clayd No. Facies (g) (g) (g) (g) (%) (%) (%) 09LW-4 St 179.0 12.7 0.0 191.7 93.4 6.6 0.0 09LW-8 W 79.5 3.4 1.4 84.2 94.4 4.0 1.6
09LW-9 Fmc 36.4 31.9 0.0 68.3 53.3 46.7 0.0
09LW-14 Smc 61.7 0.0 18.2 79.9 77.2 0.0 22.8 09LW-15 SSm 29.1 49.9 0.0 79.0 36.8 63.2 0.0 aSand (g) + Silt (g) + Clay (g) b[Sand (g)/Total (g)]*100 c[Silt (g)/Total (g)]*100 d[Clay (g)/Total (g)]*100
154
Table B-2a. Grain Size Distribution and Cumulative Weight Percents of Sediment Samples. Sample 09LW-4 (St) Sample 09LW-8 (W) Wt. of Wt. of Size Size ϕ Fraction Cumulative Cumulative ϕ Fraction Cumulative Cumulative size (g) wt. (g) wt. (%) size (g) wt. (g) wt. (%) -1 0 0 0 -1 0 0 0 0 0 0 0 0 0.7 0.7 0.83 1 1.4 1.4 0.73 1 2.8 3.5 4.16 2 40.6 42 21.91 2 43.3 46.8 55.58 3 105.5 147.5 76.94 3 27.9 74.7 88.72 4 31.5 179 93.38 4 4.8 79.5 94.42 5 0 179 93.38 5 0 79.5 94.42 6 12.61 191.61 99.95 6 0 79.5 94.42 7 0.09 191.7 100 7 3.35 82.85 98.4 8 0 191.7 100 8 1.35 84.2 100
Sample 09LW-9 (Fmc) Sample 09LW-14 (Smc) Wt. of Wt. of Size Size ϕ Fraction Cumulative Cumulative ϕ Fraction Cumulative Cumulative size (g) wt. (g) wt. (%) size (g) wt. (g) wt. (%) -1 0 0 0 -1 0.1 0.1 0.13 0 0.2 0.2 0.29 0 0.6 0.7 0.88 1 2.2 2.4 3.51 1 6.7 7.4 9.26 2 14 16.4 24.01 2 37 44.4 55.57 3 16.6 33 48.32 3 16.3 60.7 75.97 4 3.4 36.4 53.29 4 1 61.7 77.22 5 0 36.4 53.29 5 0 61.7 77.22 6 0 36.4 53.29 6 0 61.7 77.22 7 31.9 68.3 100 7 0 61.7 77.22 8 0 68.3 100 8 18.2 79.9 100 (Continued in Table B-2b) 155
Table B-2b. Grain Size Distribution and Cumulative Weight Percents of Sediment Samples. Sample 09LW-15 (SSm) Wt. of Size Fraction Cumulative Cumulative ϕ size (g) wt. (g) wt. (%) -1 0 0 0 0 0.1 0.1 0.13 1 0.4 0.5 0.63 2 3.2 3.7 4.68 3 21.6 25.3 32.03 4 3.8 29.1 36.84 5 0 29.1 36.84 6 6.5 35.6 45.06 7 43.4 79 100 8 0 79 100
156
Figure B-1. The grain size distribution of samples 09LW-4, 09LW-8, 09LW-9, 09LW-14, and 09LW-15 are plotted on this soil texture diagram. For percentages see Table B-1. 157
Figure B-2. Grain size distribution of sample 09LW-14, lithofacies Smc. 158
Figure B-3. Grain size distribution of sample 09LW-4, lithofacies St. 159
Figure B-4. Grain size distribution of sample 09LW-15, lithofacies SSm. 160
Figure B-5. Grain size distribution of sample 09LW-9, lithofacies Fmc. 161
Figure B-6. Grain size distribution of sample 09LW-8, lithofacies W.
162
APPENDIX C
GEOCHRONOLOGY
163
BLUE OSL AGE DATING 164
165
RADIOCARBON AGE DATING
166
Figure C-1. Probability diagram of age data for sample 09LW-2. Calibrated age was reported as 4547 +/- 326 YBP.
167
Figure C-2. Probability diagram of age data for sample 09LW-8. Calibrated age was reported as 82.5 +/- 121 YBP. Sample is interpreted as contaminated. 168
Figure C-3. Probability diagram of age data for sample 09LW-8a. Calibrated age was reported as 4889 +/- 178 YBP.
169
Figure C-4. Probability diagram of age data for sample 09OR-11-1. Calibrated age was reported as 4731 +/- 306 YBP.