Hydraulic Relationships Between Buried Valley Sediments and Adjacent Bedrock Formations

Home , Buried valley

HYDRAULIC RELATIONSHIPS BETWEEN BURIED VALLEY SEDIMENTS AND ADJACENT BEDROCK FORMATIONS

A Thesis submitted to Kent State University

in partial fulfillment of the requirements for the

Degree of Master of Sciences

Wondwosen Mekonnen Seyoum

August 2012

Thesis written by

Wondwosen Mekonnen Seyoum

B. Sc. Addis Ababa University, 1999

M. Sc. Addis Ababa University, 2005

M. Sc. Kent State University, 2012

Approved by

Dr. Yoram Eckstein

______, Advisor

Dr. Daniel Holm

______, Chair, Department of Geology

Dr. Timothy Moerland

______, Dean, College of Arts and Sciences

Dedicated to

My Beloved Mom

SHEWAYE TILAHUN (1957-2007)

My Father-in-law

NIGUSSIE WOLDEYOHANNES (1931-2005)

TABLE OF CONTENTS

LIST OF FIGURES ...... VII

LIST OF TABLES ...... X

ACKNOWLEDGEMENT ...... XI

CHAPTER 1 INTRODUCTION ...... 1

1.1. Introduction ...... 1

1.2. Earlier research ...... 5

1.3. Objective of the study ...... 11

1.4. Description of the study area ...... 12

1.5. Geology and hydrogeology ...... 14

1.5.1. Glacial deposits ...... 15

1.5.2. Bedrock geology ...... 19

CHAPTER 2 METHODOLOGY ...... 25

2.1. Introduction ...... 25

2.2. Data ...... 26

2.3. Conceptual model development ...... 28

2.3.1. Hydrostratigraphic units ...... 29

2.3.2. Hydraulic parameters ...... 31

2.3.3. Groundwater recharge and discharge ...... 37

2.3.4. Groundwater levels and flow directions ...... 39

2.4. Numerical Model Construction ...... 39

2.4.1. Introduction ...... 39

2.4.2. Finite difference approximation ...... 42

2.4.3. Model design and model layers ...... 45

2.4.4. Hydraulic conductivity and anisotropy ...... 47

2.4.5. Boundary conditions ...... 49

2.4.6. Drain boundary ...... 53

2.4.7. Recharge boundary ...... 55

2.4.8. Calibration ...... 58

2.4.9. Mass balance ...... 63

CHAPTER 3 RESULTS ...... 64

3.1. Stratigraphy and hydrostratigraphic units ...... 64

3.2. Hydraulic parameter estimation of the buried valley sediments (Outwash) ...... 70

3.2.1. Correction for partial penetration ...... 71

3.2.2. Transmissivity and hydraulic conductivity analysis ...... 72

3.2.3. Spatial distribution of hydraulic parameters ...... 73

3.3. Conceptual groundwater model...... 74

3.4. Numerical Model Calibration ...... 79

3.5. Numerical Model results ...... 82

3.5.1. Simulated hydraulic parameters...... 83

3.5.2. Simulated hydraulic heads ...... 85

3.5.3. Model mass balance...... 89

CHAPTER 4 DISCUSSION ...... 94

4.1. Hydraulic characteristics of the buried valley sediments ...... 94

4.2. Numerical model ...... 96

CHAPTER 5 SUMMARY AND CONCLUSION...... 102

REFERENCES ...... 105

APPENDIX...... 112

I. Cross-sections across the buried valley showing the various stratigraphic units ...... 112

II. 2D conceptual model...... 116

III. Inflow-outflow estimation using Darcy’s Law ...... 117

IV. Calculation of the hydraulic parameters for the buried valley sediments ...... 118

V. Observed (field measured) Vs model computed head data...... 127

VI. Mass balance of each major aquifer layers ...... 128

VII. Estimation of rate of flow contribution from bedrock aquifers along several across

the buried valley ...... 129

LIST OF FIGURES

Figure 1.1 An example of the possible hydraulic relationships in a section across a hypothetical buried valley ...... 3

Figure 1.2 Location map of the study area ...... 13

Figure 1.3 Digital Elevation Model (DEM) showing topography of the study area ...... 14

Figure 1.4 A stratigraphic column in Cuyahoga Valley (from Corbett et al, 1988) ...... 16

Figure 1.5 Isopach map of the glacial sediments (both the till and outwash) of the study area ...... 17

Figure 1.6 Networks of buried valleys in Geauga County (Modified from ODC, 1971) ...... 19

Figure 1.7 Bedrock geologic map, with bedrock topographic contours of the area

(modified from Eberts, Bair, and De Roche, 1990) ...... 22

Figure 1.8 Stratigraphic and hydrogeologic description of the study area (Richards,

1981) ...... 24

Figure 2.1 Sample driller’s log and report (information are circled) ...... 27

Figure 2.2 Methodology chart showing steps in developing the conceptual model ...... 29

Figure 2.3 Cells showing nodes and cell notations ...... 43

Figure 2.4 A given cell i,j,k with six surrounding cells (Modified from McDonald and

Harbaugh, 1988) ...... 44

vii

Figure 2.5 Published values of hydraulic conductivities from Halford and Kuniansky

(2002) and Domenico and Schwartz (1990) ...... 49

Figure 2.6 Schematic map view representation of boundary conditions in the bedrock units and buried valley sediments of the glacial drift ...... 51

Figure 2.7 Schematic representation of a drain in a single cell ...... 55

Figure 2.8 Boundary conditions of all model layers and grid design ...... 57

Figure 2.9 Components of calibration target ...... 61

Figure 3.1 Isopach maps of various units ...... 66

Figure 3.2 Isopach map of Berea Sandstone ...... 67

Figure 3.3 Three dimensional hydrostratigraphic model ...... 68

Figure 3.4 Layering along different model rows and columns (vertical exaggeration

= 10) ...... 69

Figure 3.5 Histograms of estimated transmissivity (a) and hydraulic conductivity (b) for sand and gravel aquifers of the glacial drift ...... 72

Figure 3.6 Distribution of estimated transmissivity values ...... 74

Figure 3.7 Groundwater level map and flow direction in the upper aquifers: Pottsville

Formation and sand and gravel (Outwash) of the buried valley ...... 75

Figure 3.8 Potentiometric surface map and flow direction in the lower aquifer: Berea

Sandstone...... 76

Figure 3.9 Three dimensional conceptual model showing the groundwater flow in the bedrock units and drift sediments ...... 78

viii

Figure 3.10 Model computed versus observed head data ...... 80

Figure 3.11 Observed heads versus residual heads ...... 81

Figure 3.12 Spatial distributions of the calibration targets ...... 82

Figure 3.13 Model simulated transmissivity distribution in the sand and gravel

(Outwash) aquifer...... 85

Figure 3.14 Maps showing hydraulic heads in model layers ...... 86

Figure 3.15 Model sections showing hydraulic head and flow directions ...... 87

Figure 3.16 Spatial distributions of model generated flow directions (blue arrows indicate the direction) ...... 88

Figure 3.17 Flow directions (blue arrows) on one side of the interface between bedrock aquifers and sand and gravel aquifer (model column 38) ...... 91

Figure 3.18 Mass balance in each aquifer layers ...... 93

Figure 4.1 Mass balance of the buried valley aquifer ...... 100

LIST OF TABLES

Table 2.1 Estimated values of hydraulic parameters from various sources...... 33

Table 2.2 Summary of initial model parameters...... 52

Table 3.1 Summary of observed and corrected specific capacity data ...... 70

Table 3.2 Summary statistics of the estimated transmissivity and hydraulic conductivity ..... 71

Table 3.3 Summary statistics of calibration ...... 79

Table 3.4 Simulated hydraulic parameter values ...... 83

Table 3.5 Model simulated layer transmissivity values ...... 84

Table 3.6 The entire model mass balance ...... 90

Table 3.7 Data of the water budget in the buried valley sediment ...... 92

ACKNOWLEDGEMENT

First off, I would like to express my sincere gratitude to my advisor, Dr. Yoram Eckstein, for providing me a good basis and understanding, guidance and suggestions throughout the research. I also would like to acknowledge my committee members, Dr. Abdul

Shakoor and Dr. Elizabeth Griffith. I offer my compliments and respects to all of those who supported me in any aspect during my study. I sincerely thank to the Department of Geology, Kent State University for all aids provided. Lastly, I owe my loving thanks to my wife, Helen Woldeyohannes, her encouragement and support was enormous.

CHAPTER 1

INTRODUCTION

1.1. Introduction

According to the Ohio Department of Natural Resources (ODNR) Fact Sheet 97-46

(1995): “Some of the highest yielding aquifers in the state are located in the buried valley system. Extensive deposits of sand and gravel make these underground reservoirs some of the largest producers of ground water in the Midwest. A buried valley is simply an ancient river or stream valley that has existed perhaps hundreds of thousands to millions of years ago and since has been filled with glacial or unconsolidated sediment.

This sediment is comprised of gravel, sand, silt, and clay.” This lithological heterogeneity results in spatial variability of hydraulic properties of the sediment. Often, the pattern of hydraulic properties is more complex where the sediments interface with the bedrock formations.

In regions where there are different hydrostratigraphic units with variable hydrogeologic characteristics, the production and capacity of water wells depends on the individual hydraulic properties of each hydrostratigraphic unit and the relationship

to one another depending on the hydrogeological condition of the area. In Northeast

Ohio, there are four well determined hydrostratigraphic units: (1) the glacial drift which covers the bedrock, (2) the Pottsville formation, (3) the Cuyahoga Shale and (4) the

Berea Sandstone (Eberts, Bair and De Roche, 1990). Hydraulic characteristics of the glacial drift, which contains low-transmissivity glacial till inter-layered with higher permeability facies of the sand and gravel, are highly heterogeneous. The sand and gravel deposits of the buried valleys can produce ample amount of water for domestic and commercial uses. Aquifer test data on these deposits by Ohio Drilling Company

(1971) shows transmissivity values in the range of 200 to 1,000 m2/day. Numerous residential water wells tap water from such buried valley aquifer in Northeast Ohio. The sand and gravel deposits found in buried valleys are capable of producing large amounts of water depending on several hydro-geological factors such as the extent and thickness of the layers, and their lithological and hydraulic characteristics. Since the buried valley sediments are bounded by the bedrocks, their productivity also depends on the connection and relationship with adjacent bedrock aquifers. The same might be true for the bedrock aquifers, which might depend on the buried valley sediments for recharge.

The productive units of the glacial drift might be found in buried valleys adjacent to the bedrock aquifers. Till, which has most likely a poor infiltration capacity, if it covers the top part of the glacial drift, might impede the recharge to the buried valley aquifer, as well as the bedrock aquifers. The buried valley aquifer might get recharge via adjacent bedrock aquifers. Inversely, the bedrock aquifers might be recharged from the glacial

drift aquifers. Figure 1.1 shows one hypothetical pattern of hydraulic relationships where the buried valley aquifer is recharging the bottom bedrock aquifer, while being recharged from the top bedrock aquifer (as indicated by the hydraulic heads shown in the piezometers). Therefore, besides the individual hydraulic properties, the hydraulic connection or relationships between these heterogeneous aquifers determine the productivity as well as the sustainability of ground-water resources in a buried valley.

Furthermore, direct exposure of the buried valley highly permeable formations to the ground surface might facilitate the pathway to contamination in deep bedrock aquifers.

In addition, the buried valleys are likely to provide interconnected bodies of high permeability from the shallow groundwater to the deep aquifers (Sandersen and

Jørgensen, 2003). This might increase the vulnerability of the deep or bedrock aquifers to contamination.

Bedrock units

Buried valley

Figure 1.1 An example of the possible hydraulic relationships in a section across a hypothetical buried valley

The hydraulic relationship of buried valley aquifers with the adjacent bedrock formations will be investigated in the following study using a 3D numerical groundwater model simulation. Existing maps, data from the geological and hydrological analysis of water well logs and drilling reports available from ODNR will be employed to understand the characteristics of each aquifer and their relationship in a location where the buried valley is found interfaced with the bedrock formations: the Pottsville Formation, the

Cuyahoga Shale and the Berea Sandstone. Lithologic data from well logs, transmissivity values which will be determined from pumping or production test data and/or found from literature, and general hydrogeological interpretation will be used to construct first the conceptual model which will be then converted into a grid model for simulations using finite-difference method. The model will be calibrated against the observed water level records from pumping test data. Once calibrated, the hydraulic properties, flow direction and water budget within discrete sections of the buried valley can be determined providing a better understanding of the system.

In the process of conceptual modeling, the stratigraphy and hydrostratigraphic units will be modeled from drillers log giving better visualization and understanding of each unit.

The hydraulic parameters of each hydrostratigraphic units will also be assessed helping

to understand the spatial pattern in the system. The numerical simulation will facilitate precise simulation of hydraulic head, determination of flow direction, and water balance estimation.

1.2. Earlier research

Numerous geological and hydrogeological studies have been conducted in Northeast

Ohio dealing with the characterization of the glacial and the bedrock units, on county and township scales (e.g., Baker, 1957; Rau, 1969; Wells, 1970; ODC, 1971; Robinson,

1972; Walker, 1978; Pettyjohn and Henning, 1979; Kerschner, 1981; Richards, 1981;

Dick, 1982; Heaton, 1982; Krulik, 1982; Williams, 1983; Macdonald, 1987).

Eberts, Bair and De Roche (1990) assessed spatial and temporal variation of groundwater quality, and determined the regional groundwater flow pattern and made a prediction on regional changes in groundwater level that might occur as a result of increased demand, in Geauga County. They constructed regional numerical groundwater model to determine groundwater flow pattern, estimate residence times as well as prediction of various scenarios. They concluded that recharge is totally from precipitation, and groundwater flows in the glacial and Pottsville formations are localized in nature. While in the Cuyahoga Group, groundwater flow is vertically downward. Flow is radial in Berea Sandstone, towards sub-crops in the adjacent buried

valleys. Their simulation of groundwater level change resulting from the predicted increase in water demand has been estimated at a maximum of 3m decline.

Robinson (1972) analyzed physical parameters like thickness and texture from Geauga

County well data within Cuyahoga, Chagrin and Grand River valleys and used statistical techniques to determine the hydrologic characteristics and local groundwater resource.

Well characteristics were correlated using frequencies, standard deviations, means and skewness of sand, gravel, clays and silts. The research verified that there are intricate buried valley systems and provided the hydrologic characteristics of the sediments. The buried valley sediments of Upper Cuyahoga Valley are poorly productive due to the abundance of silts within sand and gravel, whereas in Chagrin River Valley, the buried valley sediments consist of clean and well sorted sand and gravel, and are best for domestic supplies.

Richards (1981) conducted a quantitative hydrogeological assessment, south of the present study area, in South Russell Village using field data and driller’s log. She evaluated recharge, groundwater flow, hydraulic parameters, water quality and groundwater potential in the area. She indicated that groundwater flows from bedrock highs of Pottsville Formation (recharge areas) to valleys or streams and generally the groundwater in the area is of good quality (conforming to the US EPA Drinking Water

Standards). She estimated hydraulic conductivity higher for the sand and gravel deposits

and annual recharge rates generally at 5.0E-04 m/day but lower if the Pottsville

Formation is absent due to erosion.

Jagucki and Lesney (1995) conducted an assessment of groundwater level and flow direction in Geauga County using groundwater level data measured through 1986 – 94.

According to the study, groundwater in Pottsville Formation and glacial deposit corresponds to the land surface configuration and flows from the uplands to the adjacent streams and buried valleys. Groundwater flow is downward in Cuyahoga Group whereas it is outward from Berea Sandstone. A comparison of water level measurements at different times indicated that 30% of water level changes are less than

0.3m in magnitude and in 80% of wells, water level changes are in the range of ±1.5m.

Kushner (2006) characterized and correlated the most recent glacial sediments of a buried valley in Summit County using laboratory and field techniques. He used statistical analysis of texture, composition and lithologic description of samples from core data. He correlated sediments from the buried valley with the regional stratigraphy and established a glacial stratigraphy to understand the sequence of events during

Quaternary Period.

Ritzi et al. (1994) used geostatistical models to determine the aquifer heterogeneity in the Miami River buried valley aquifer, near Dayton, Ohio. They concluded that

heterogeneity is more complex in glacial sediments which are spatially highly variable. In places where there is a lack of data they evaluated lithological uncertainty and determined the uncertainty associated with inferring facies boundary from a limited well log data, zoning permeability and preferred pathways in heterogeneous buried valley aquifers.

Venteris (2007) constructed three dimensional model of glacial stratigraphy in Delaware and Franklin Counties of central Ohio. He used driller’s logs of water well data from

ODNR and engineering borings from Ohio Department of Transportation and EPA to construct 3D stratigraphy. He correlated and grouped the available log information into local stratigraphy which contains alluvium, till, sand and gravel, and shale. He used geostatistical interpolation techniques to build surfaces and then 3D stratigraphic model. His results confirm that there is a thick basal deposit of sand and gravel along the valley.

Russell et al. (2004) presented a review paper summarizing all the geological and hydrogeological information about buried valley aquifers of Canada. They discussed the stratigraphy of buried valleys and the “distribution, geometry and scale of valleys and the sediment facies of valley fill” and their hydrogeological characteristics. They recommended for further investigation a long list of relevant subjects, including stratigraphic architecture and sedimentology studies, aquifer extent, continuity and

transmissivity, hydraulic barriers and vertical hydraulic connections, hydrochemistry, and protection and sustainability of buried valleys.

Basin analysis applied to modeling buried valleys in the Great Lakes basin was conducted by Sharpe and Russell (2004). The study focused on development of a conceptual model of a buried valley for an input into numerical groundwater model through the application of basin analysis. Basin analysis provides a foundation for developing an accurate basin model. The model can be used to improve the extrapolation of knowledge from data-rich to data-poor areas in order to predict the nature of the basin fill. They showed the role of basin analysis in data collection, model development and improving assessment of regional hydrogeological significance.

Allen et al. (2006) characterized hydrogeology and groundwater resource potential of buried valley aquifers in SW Ireland. The area has the same setting as Northeast Ohio which was glaciated in early Pleistocene. A buried valley is a major groundwater source for the area. They used site investigations, boreholes and geophysical techniques, and measurements of hydraulic properties to characterize the potential of this aquifer. They noted that buried valley aquifers possess significant groundwater resources but not well understood. They suggested that this might be due to the complex nature of the buried valley aquifers, less readily identified than other aquifer types and usually highly site

specific. However, such buried valley aquifers are widespread and found at shallow depth which makes the exploitation cost relatively low.

Similarly, Sandersen and Jørgensen (2003) used extensive geophysical survey and lithological logs to determine the geometry of buried valley aquifers in Denmark. They used seismic, gravimetric and electromagnetic surveys in their study to define extent, structure, geometry, orientation and geographical distribution of buried valleys. They mapped the buried valleys, and characterized their influence on groundwater resource and vulnerability.

Seifert et al. (2008) assessed the impact of buried valley sediments on groundwater vulnerability through uses of alternative conceptual models. Often buried valley sediments are neglected or are not detectable while constructing groundwater model.

So, they developed a groundwater model in order to help quantify the effect of the valley on groundwater vulnerability first (1) including the buried valley and then (2) without including the buried valley sediments. In both conditions the model simulates well the hydraulic heads. However, they showed that fluxes, travel path and travel times are different when the buried valley is included. As a result the groundwater is significantly more vulnerable when the valley is included. Thus, the buried valley sediments have a greater role not only in groundwater potential but also when dealing with contaminant transport.

Most of the previous studies noted that buried valley aquifers are capable of producing significant amounts of groundwater. Complex nature of these aquifers and less understanding of the system requires further investigation. Majority of the available studies deals with geometry, architecture and physical properties of the buried valleys.

The following study will attempt to derive quantitative relationship with the adjacent bedrock aquifers using numerical groundwater simulation, providing a site-specific model that can be easily converted into a generic model for use in similar glaciated areas.

1.3. Objective of the study

The general objective of the study is to assess the relationship of the buried valley aquifers with the bedrock aquifers using a steady-state numerical groundwater simulation model - with specific tasks of:

 building three dimensional stratigraphic model of the various lithologies

across a buried valley from well logs, existing maps and geological

interpretation,

 determining the hydraulic properties from water well production test

data,

 developing a conceptual hydrogeological model for a section of buried

valley,

 constructing a 3D numerical groundwater model for a section of buried

valley,

 determining the hydraulic relationship between the buried valley

sediments and bedrock formations,

 testing the groundwater mass balance for model cells or layers along the

buried valley interface with the bedrock formations.

1.4. Description of the study area

The study area is located in the western part of Geauga County, which falls in Chester and Russell Townships, Northeast Ohio (Figure 1.2). The area is in Chagrin River drainage basin which is a part of Lake Erie drainage basin. The topographic elevations range from

300m near the river to 390m (a.s.l.) on the upland. The mean annual precipitation is around 1160 mm and the mean annual temperature is approximately 80C as recorded in the nearby Chardon station. The total area of the study is about 24 sq. km. with approximate dimension of 6km by 4km. There are about 350 domestic water wells penetrating various rock units in the study area.

Figure 1.2 Location map of the study area

Topographically, the area is dominated by gently rolling hills, some flat lands and steep slopes along the upper Chagrin River Valley. The uplands are relatively flat whereas steeper slopes appear near stream valleys. The topography is generally controlled by bedrock morphology. The area is dissected by the upper Chagrin River along the central part and bounded by hills on the sides (Figure 1.3). The river follows or parallels the buried valley because the ancient valley was not completely filled by the glacial

sediments (Baker, 1964). The uplands are characterized by radial drainage pattern, with flows toward the side streams or valleys.

Figure 1.3 Digital Elevation Model (DEM) showing topography of the study area

1.5. Geology and hydrogeology

Groundwater in the study area is extracted from unconsolidated glacial drift sediments and from consolidated sedimentary bedrock. The sedimentary bedrock found in the area ranges in age from Devonian to Pennsylvanian. The stratigraphic column for the

region is shown in Figure 1.4. Various geologic processes such as uplift, erosion, deposition and glaciations are responsible for shaping the topography of the bedrock formation. As a result, the bedrock topography is characterized by rolling hills (uplands) and valleys (Baker, 1964). In the Pleistocene, the advancement of glacial episodes in the area carved out and deepened the bedrock valleys. As the glacier receded, large amount of material carried by the ice were deposited and covered the area. The current topography is a result of glacial processes and bedrock erosion. The outwash deposits of the glacial sediments have a primary porosity that can transmit and store water.

Similarly, bedrock units have also primary porosities such as found in sandstones and secondary porosity or fracture porosity formed as a result of valley stress relief fractures. The study area consists of bedrock units across the buried valley covered by the glacial formations, including till and outwash.

1.5.1. Glacial deposits

During the Pleistocene epoch (“Ice age”), glaciers scoured the hilltops and deepened some valleys, producing rock debris (drift) that was carried along with the ice and deposited by melt water (outwash) in the bedrock valleys, or directly by the ice (till) when the glaciers melted (Richards, 1981). In general, the unconsolidated materials of glacial drift are characterized by sands, gravels, silts and clays.

Figure 1.4 A stratigraphic column in Cuyahoga Valley (from Corbett et al, 1988)

The outwash deposits consist of sand and gravel having some degree of bedding, sorting and rounding. As the outwash melt water followed ancient channels, these outwash materials were deposited in buried channels (eskers) or valleys. However, tills, resulting from the direct deposition by the ice, are characterized by poor sorting, angular pebbles and boulders in a silty clay or clay matrix. The uplands of the bedrock are covered by till

(mostly ground moraine) whereas the valleys are filled by both till and outwash materials. These materials are thick in buried valleys, where their thickness reaches up to 80m within the study area (Figure 1.5).

Hydrogeologically, the glacial sediment can be categorized into two types: outwash deposit and the till. The outwash deposits are coarse grained, well sorted materials, mainly composed of sand and gravel. In the study area, these materials are found in the buried valleys forming networks of intersecting buried valley sediments (Figure 1.6).

Large yields of water wells are available in these sediments. The Chagrin Falls municipal wells field, which is found south of the study area in buried valleys, yields over 300 m3/day (Grasso, 1986). The till, usually covering the bedrock uplands is predominantly composed of clay and silt which makes it a low-permeability material. Thus the till is not considered a reliable source of groundwater.

Figure 1.5 Isopach map of the glacial sediments (both the till and outwash) of the study area.

Ohio Drilling Company (1971) evaluated several buried valleys in Northeast Ohio for groundwater potential. According to their study, the sand and gravel layers found specifically in the study area are potentially useful for development of domestic and commercial wells. There are several domestic wells that tap groundwater from the outwash sediments in the area. These wells are located along the valleys where the deposits are thick. In previous studies the buried valley materials and the till were not differentiated. In the following study, the outwash and till deposits are differentiated on cross-sections across the valley constructed from drillers’ logs, to illustrate the relationship with the bedrock formations (Appendix I).

Figure 1.6 Networks of buried valleys in Geauga County (Modified from ODC, 1971)

1.5.2. Bedrock geology

The sedimentary bedrock units in Geauga County range in age from Devonian to

Pennsylvanian (Figure 1.4). The oldest bedrock units that crop out in the area are the

Chagrin Shale, Cleveland Shale and Bedford Shale which for this study are considered together as Pre-Berea formation. These rock units are hydrologically poorly understood and insignificant, as they are generally characterized by poor groundwater production

capacity and often contain brackish groundwater, thus they are lumped together. Above the Pre-Berea formation, there are three important stratigraphic units of the sedimentary bedrocks that are considered in this study (Figure 1.7). From the oldest to the youngest, these are Berea Sandstone, Cuyahoga Group, and Pottsville Formation.

These rock units dip uniformly to the south direction approximately 10 to 20 ft per mile or 1.9E-3 to 3.8E-4 (Baker, 1964).

Pottsville Formation

Pottsville Formation is the youngest bedrock unit in the study area. It is commonly found capping topographically high areas, bounded on the top by an erosional surface and usually covered by glacial till. The thickness of this formation reaches in the study area up to 35m, but the maximum thickness elsewhere may be as much as 50m. The

Pottsville Formation consists of two members found in the study area: the

Connequenessing Sandstone and the Sharon Conglomerate. The Connequenessing

Sandstone is the youngest member which is predominantly quartz sandstone with a matrix of silt and clay. The Sharon Conglomerate is pebbly quartz sandstone possessing a pebbly basal conglomerate in some areas (Baker, 1964). This formation is the major aquifer exploited in the region. It is found at a relatively shallow depth and yields ample amount of groundwater. Water wells drilled into the Pottsville Formation may yield from 50 to 500 m3/day (Richards, 1981). Local variations in the aquifer including fractures, variable thickness, localized lithologic changes and degree of cementation

contribute to a wide range of yields. Various studies show that the transmissivity of this formation ranges between 10 to 200 m2/day.

Cuyahoga Group

The Cuyahoga Group consists of interbedded shales and sandstones found above the

Berea Sandstone. Baker (1964) divided this group into three members: the Meadville

Shale, Sharpsville Sandstone and the Orangeville Shale which are characterized by interbedded siltstone/sandstone with shale. The thickness of this group varies spatially, as it is bounded on the top and bottom by disconformities, where the total thickness of this group reaches up to 70m. The maximum thickness of this unit in the study area is about 55m. None of the formations in this group are permeable enough to give ample amount of groundwater. This is because of very low primary porosity and most of the groundwater moves along the bedding planes and fractures.

Wells in this group generally yield less than 30 m3/day. Jenkins (1987) estimated the average horizontal hydraulic conductivity of the Cuyahoga Group using a specific capacity data of the drillers’ production tests and is 0.2 m/day. This unit acts as a confining layer to the underlying aquifer, Berea Sandstone. Eberts, Bair, and De Roche

(1990) considered this unit as a leaky confining unit in their regional model.

Figure 1.7 Bedrock geologic map, with bedrock topographic contours of the area

(modified from Eberts, Bair, and De Roche, 1990)

Berea Sandstone

Berea Sandstone underlies the Cuyahoga Group. It is composed of a relatively well sorted fine to coarse grained sands (Baker, 1964). It is present throughout the study area except in places where it is dissected by a buried valley. This unit is relatively uniform in thickness which is about 15 - 20m where it is overlain by the Cuyahoga

Group. Wells from this bedrock unit have a low to moderate yield ranging from 25 to

200m3/day (Rau, 1969). However, when it is fractured, wells can give higher yields. This rock unit is extensively jointed and weathered in places where it is exposed near the surface (Baker, 1964). Williams (1983) indicated that there is a correlation between well yields and wells distance to sub-crop boundaries. Rau (1969) reported an average transmissivity of 45m2/day and the corresponding average hydraulic conductivity of

2.5m/day. This unit is primarily a confined aquifer except in buried valley where the confining Cuyahoga Group is absent due to pre-glacial erosion.

Pre-Berea formations

The rock units immediately below Berea Sandstone consist of various clay shale or silty shale. There are no wells taping groundwater from these formations in the study area.

However, there are wells finished outside the study area and most of the wells have very low yields or were reported dry (Richards, 1981). In this study, this unit is considered as the bottom impermeable boundary. Generally, the hydrogeology of the stratigraphic units in the area is best summarized by Richards (1981) in the Figure 1.8.

Lithologic Hydrogeologic Era Period Formation Description description Mostly till with

some sand and

Moderate to high gravel deposits of yields in Sand and limited areal Drift gravel, till not extent, deposits

considered as CENOZOIC

Quaternary of over 300ft in good source the Chagrin River

buried valley -

Quartz sandstone and pebbly Moderate to high sandstone

yields (in

ing SST Member Pottsville Connequeness fractures), good Formation Quartz sandstone quality water but

and pebbly subject to Pennsylvanian

sandstone, and contamination conglomerate, thin or absent

shale unit

Sharon Sharon Conglomerate Member

Meadville Low yields, higher shale yields available Cuyahoga Shale and some Sharpsville when fracture

Sandstone sandstone Group exists, good PALEOZOIC Orangeville quality water Shale Low to moderate

yields, higher Mississippian yields when Berea Sandstone Quartz sandstone fractured, acceptable water

quality

Not considered as Shale, siltstones Pre-Berea Formations good source of and sandstones

water Devonian

Mississippian Mississippian

Figure 1.8 Stratigraphic and hydrogeologic description of the study area (Richards, 1981)

CHAPTER 2

METHODOLOGY

2.1. Introduction

This chapter deals with the methodology and data used in the entire modeling process.

The methodology can be categorized in two parts: construction of the conceptual model and numerical modeling. Conceptual modeling involves preparation and assimilation of all the information in a way simplified for application in the numerical model. It encompasses understanding of the hydro-geological system of the area, delineating the hydrostratigraphic units and determining their hydraulic parameters, and outlining the groundwater flow system. The numerical modeling involves conversion of the conceptual into a mathematical model and solving the mathematical equation.

ArcGIS 9.3 was used as a main tool in constructing the conceptual model. It was used to delineate the model area (a part of watershed) from USGS DEM (Digital Elevation

Model) and in preparation of all layer elevations, hydraulic conductivity maps, and potentiometric surface maps. Geostatistical analysis was done to generate continuous surfaces of layer elevations, hydraulic conductivities and cross-sections. Later all the files were imported into GMS (Groundwater Modeling System) software which is the

platform that used to build the 3D hydrostratigraphic model and the numerical model.

The map projection used in the whole process is NAD (North American Datum) 1983 geographic and StatePlane-Ohio-North-FIPS-3401 projected coordinate system.

2.2. Data

In order to establish initial values for model inputs such as horizontal hydraulic conductivity, vertical hydraulic conductivity, recharge, hydrostratigraphic units, etc, data were compiled for both unconsolidated and bedrock deposits in the study area. The basic source of data used in this study was drillers’ water well logs and reports. A total of 312 borehole data points, obtained from Ohio Department of Natural Resources

(ODNR) website, were used to build the conceptual model and prepare input data for the numerical model.

Figure 2.1 Sample driller’s log and report (information are circled)

The types of information extracted from borehole reports can be categorized in three:

(1) the well location, (2) the lithological log description and (3) pumping test data. The pumping test information was used for determination of transmissivity and hydraulic conductivity. It consists of information like pumping rate, drawdown, static water level

(SWL) and duration of pumping (Figure 2.1). The drillers’ log description (lower part of

Figure 2.1) has information about the lithologies with their respective depth. This is used to delineate stratigraphic boundaries and model the hydrostratigraphic units.

Because of quality and reliability issues with the drillers’ report (lithological descriptions in particular), existing maps, data and reports were also used for cross checking purposes. Reports from previous works were used to extract additional information which was not determined within the framework of this study such as rate of recharge and hydraulic parameters of the bedrock units (Richards, 1981; Rau, 1969; ODC, 1971;

Winslow & White, 1966 and Jenkins, 1987).

2.3. Conceptual model development

Since, the study involves determination of the relationship between a buried valley and bedrock, it is necessary that a 3-dimensional conceptual model, which can show the physical characteristics of the formations, is constructed. The key objective in such model is to outline in three-dimensions the geometry and spatial distribution of the highly permeable materials within the glacial sediments along with the other formations. The series of steps used in the development of the conceptual model is outlined in the Figure 2.2. Building of the three dimensional model primarily begins with constructing several cross-sections which allows spatial interpretation of the stratigraphy and classification of the materials based on their hydraulic properties. Once

the materials are grouped, their hydraulic parameters are estimated. Using water level data from the well logs, the groundwater flow net is constructed to understand the flow system and eventually 3D and 2D representations of the conceptual model is built.

Borehole data base

Groundwater recharge, Stratigraphic Pumping test boundaries data, lithologies level and flow direction

Database of Hydrostratigraphic units, hydraulic Previous layers elevation conductivity estimates review data

Interpolate layer Interpolate hydraulic Interpolate water level elevations parameters surfaces & flow directions

2D and 3D conceptual models

Figure 2.2 methodology flowchart

2.3.1. Hydrostratigraphic units

The first step in building the conceptual model is defining the stratigraphic units and then the hydrostratigraphic units of the area. Conventional method is used to identify the stratigraphic units from the drillers’ logs such as the lithological description, elevation and stratigraphic location. As discussed in previous section (geology & hydrogeology), previous researchers divided the bedrock into different

hydrostratigraphic units such as Richards (1981). She defined the Pottsville Formation and Berea Sandstone as moderate to high permeability materials whereas the Cuyahoga

Shale as low permeability material. Regarding the glacial sediments, most of the researchers described the coarse-grained materials of buried valleys as productive aquifers and the glacial till as very low permeability material but considered them together as one layer in previous models. For instance, Eberts, Bair and De Roche (1990) took these highly permeable materials as a one layer along with the low permeability till in their modeling work in Geauga County.

However in this study the glacial till and the coarse grained material of the buried valley sediments are considered separately. The basis for categorization is grain size (as described on drillers’ logs), i.e. material with more fines has low permeability and material with coarse grains will have relatively higher permeability. Even though the contribution of the groundwater flow is from both materials, the assumption here is that the majority of flow contribution is from the coarse grained materials. So, based on this assumption from the lithological logs of boreholes, materials with fines such as clay are categorized into low permeability till. Coarse grained materials are grouped into the high permeability buried valley sediments (Outwash). Very thin layers of coarse-grained materials found in the till, which are not interconnected and scale wise insignificant, were lumped with the low permeability group. In the bedrock, sandstone and conglomerates with thin layers of shale (found in few well logs) were grouped as

Pottsville Formation. The thick shale layer with thin layers of sandstones was mapped as

Cuyahoga Shale. The sandstone underlying this layer was regarded as Berea Sandstone based on the local stratigraphy. Shale found in some of deep boreholes below the Berea

Sandstone was named as pre-Berea shale.

Besides the lithological description of each layer, thickness information for each layer was also extracted. Elevation of each layer was obtained by subtracting the total thickness from ground surface elevation. These elevations were used to construct the

2D and 3D stratigraphic model which later was used as a frame for the numerical model.

Interpolation of layers’ elevation of every well point provided continuous surfaces for each layer.

2.3.2. Hydraulic parameters

Hydraulic parameters such as hydraulic conductivity and/or transmissivity were determined previously in Geauga County and adjacent areas by various researchers, e.g.

Richards (1981), Rau (1969), ODC (1971), Winslow & White (1966), and Jenkins (1987).

The hydraulic parameters given by these researchers are summarized in the table below

(Table 2.1). As shown in the table, the estimated hydraulic conductivity values for buried valley sediments in Cuyahoga River Valley is less than 50 m/d whereas in Chagrin River

Valley, it reaches up to 600 m/d. This indicates that the hydraulic parameters are highly

variable and it is necessary to estimate the site-specific hydraulic parameters for the buried valley sediments in the study area. The most available pumping test data in the area were short-term productivity test data from driller’s log report which contain pumping rates, duration and total drawdown. Thus, conventional determination of transmissivity from specific capacity data (see next section) was applied to estimate the hydraulic parameters for the buried valley sediments of the glacial drift. Yet, as the hydraulic properties of the bedrock material are less variable and the range of values given by previous researchers is relatively narrow, they were adopted for the bedrock units in the study area.

Table 2.1 Assumed values of hydraulic parameters from various sources

Hydraulic conductivity Transmissivity Unit/formation (m/day) (m2/day) Source Remark Buried valley In Cuyahoga sediments 32 900 ODC (1971) river valley, " 45 700 located South − Eberts, Bair and of the study " 195 De Roche (1990) area Pottsville − Winslow & White In Portage Formation 157 (1966) County " 1 - 20 − Sedam (1973) Geauga County − Munson Cuyahoga Shale 0.1 - 0.2* Jenkins (1987) Township Berea Sandstone 2.5 45 Rau (1969) Northeast ohio Sand and gravel 0.25 - 600* − South of the Pottsville − study area Richards (1981) Formation 0.25 - 20* (South Russell Berea Sandstone 0.1 - 4* − village) Sharon Sandstone 0.007 - 96* 0.2 - 530* Maharjan (2011) Geauga County * indicates values determined by analysis of specific capacity data but the rest using time- drawdown analysis.

Transmissivity determination using specific capacity data

The type of pumping test in most of the data in the area were well performance or specific capacity test which is a test conducted using a constant rate for a given duration

(usually lasts for a couple of hours) and the amount of total drawdown and the duration of pumping is noted at the end of the test. Specific capacity is the rate of pumping per unit depth of drawdown. It is a function of the hydraulic properties of a given aquifer.

Well characteristics such as well diameter, depth of penetration, well loss are also factors that control the value of specific capacity. Therefore, to get more precise results

in calculating transmissivity using specific capacity, all these parameters should be taken into account.

One of the most widely used methods of determination of transmissivity from specific capacity is the non-equilibrium equation developed by Cooper - Jacob (1946):

Where T: transmissivity (L2T-1)

Q: pumping rate (L3T-1) s: total drawdown (L) t: duration of pumping (T) rw: radius of the well (L)

S: storage coefficient

The assumptions for this equation are (1) the aquifer is homogenous and isotropic; (2) the well should fully penetrate the aquifer; (3) well loss is negligible and (4) the effective radius is the radius of the production well. It is rarely possible to get wells ideally satisfying these criteria; so, the observed specific capacity data cannot provide precise results of transmissivity. However, there are various corrections that could be applied on the specific capacity data to satisfy the assumptions and to obtain fairly accurate values of transmissivity.

Assumptions (1) and (4) are satisfied for most of the wells. The wells in the buried valley sediments are totally cased and there is no record of practices such as gravel packing

(Richards, 1981) which would result in increasing the effective well diameter. Therefore, the casing diameter can be assumed the effective diameter of the well. The clastic material surrounding the wells can be assumed homogenous and isotropic. Regarding assumption (3), since the pumping rate for most of the wells was low (the average is 110 m3/day or 20gpm), the well loss can be considered as very low or negligible. This is because turbulent flow which contributes to well loss is negligible at lower discharge rates. The higher the pumping rate the more likely there is turbulent flow and then significant well loss. The second assumption, which is partial penetration, is the most important in determining the value of the specific capacity and thus the transmissivity.

Most of the wells in the buried valley sediments are fully cased; except for in some cases

1m (1 to 3ft) length left open at the bottom to allow water to enter into the well. A well constructed like this allows limited amount of water to enter into the well. Technically, horizontal flow to the well is then limited and the wells are fed by vertical and sub- vertical flow from the aquifer, with flow-lines converging at the narrow entrance open at the bottom of the well. As a result, the specific capacity will be highly reduced compared with a fully penetrating well, open to the full thickness of the aquifer.

Therefore, the drawdown or the specific capacity should be corrected for the effect of partial penetration in order to better approximate the true value of aquifer transmissivity.

There are several methods used to correct the effect of partial penetration. The method by Kozeny (1933), which provides fair results in non-equilibrium pumping conditions

(Driscoll, 1986 and Walton, 1988), is used to correct for the effect of partial penetration.

3 -1 : corrected specific capacity (L T /L); pumping rate per corrected drawdown

3 -1 : observed specific capacity (L T /L); pumping rate per observed drawdown

L: screen length (L) b: saturated thickness (L)

Since almost all the wells in the buried valley sediments are totally cased, with no screens, the screen length (L) was assumed equal to the length of the open (uncased) bottom part of the well, i.e. 0.3m (1ft). The saturated thickness (b) for each well was calculated from the layer elevation map of the buried valley sediments and SWL given in each well data. Storativity for unconfined aquifers ranges in value from 0.01 to 0.3. If the pumping test was conducted using observation wells, the storativity can be determined along with transmissivity. However, in this case, pumping tests were conducted using a single well, thus storativity was assumed. The error in using assumed storativity values for transmissivity determination is insignificant. Kasenow (1996) showed that in an unconfined aquifer, 50% error in assuming storativity values results in only 4% error in calculated transmissivity values. Storage assumption error as high as

94% results in transmissivity error of only 14%. Thus, the effect of assuming different values of storativity has a little effect on the calculated value of transmissivity. The buried valley sediments were found in unconfined to semi-confined condition, hence, average storativity value of 0.1 was assumed.

As it is shown in equation (1), transmissivity is found in both sides of the equation, so solving the equation linearly is not possible. Hence, the transmissivity was determined by iteration. First, a given value of transmissivity was used to calculate drawdown. The transmissivity value was iterated until the difference between the calculated and observed drawdown declined to a minimum. The iteration was done by using Excel solver function.

2.3.3. Groundwater recharge and discharge

Groundwater recharge is defined as the water that infiltrates through the unsaturated zone and crosses the water table, whereas groundwater discharge occurs where the water table intercepts the ground surface. Aquifer recharge may also occur as cross- formational leakage from confining to a confined formation below. The major source of recharge in the area is precipitation. The unconfined aquifers such as the buried valley sediments and the Pottsville Formation mainly get recharge from direct precipitation.

However, the lower bedrock such as Cuyahoga Shale and Berea Sandstone may get

recharge by leakage from the overlying aquifers except in valleys where they might be exposed to the surface for direct recharge. Richards (1981) indicated that the Pottsville

Formation and buried valley sediments are a major source of recharge to the Cuyahoga

Shale and Berea Sandstone. The buried valley sediments, besides direct precipitation, may get recharge from the bedrock formations depending on the hydraulic gradient.

Most of the depressions and river valleys in the area are the spots for groundwater discharge. A gain/loss study by Eberts, Bair and De Roche (1990) in Cuyahoga and

Chagrin Rivers indicated that the rivers get baseflow from the local groundwater.

Recharge rates in the area were estimated by various researchers. Pettyjohn & Henning

(1979) used baseflow separation method of river hydrograph to estimate the groundwater recharge based on the assumption that the amount discharged into the rivers is equal to the amount of recharge. A recharge rate of 4.5E-04 to 6.5E-04 m/day was estimated for Chagrin River at Willoughby (near the study area). Richards (1981) estimated recharge to the Pottsville Formation using flow-net analysis. She estimated a recharge rate of 5.0E-04 m/day and also noted that the majority of recharge occurs through the Pottsville Formation. Based on these estimates, a range of recharge values of 4.0E-04 to 6.0E-04 m/day was used as an input into the numerical model.

2.3.4. Groundwater levels and flow directions

Water levels reported as the static water level in the production tests were used to construct groundwater level map and infer flow directions. Water level elevation in each well was used to construct the water level contour map with the help of interpolation tools in ArcGIS 9.3. Arrows were drawn on the maps perpendicular to the water table elevation contours in order to indicate the flow direction. Two water level maps were constructed: (1) for the unconfined aquifers, which includes the buried valley sediments and Pottsville Formation (2) for Berea Sandstone. These water level maps were superimposed with the regional potentiometric surface maps of these aquifers which were done by ODNR, to compare the interpolation result and pattern of flow. Using the water level maps and ground elevation data, 2D profile and 3D model was done to see the groundwater flow system.

2.4. Numerical Model Construction

2.4.1. Introduction

The hydraulic relationship among the complex layers of the bedrock units and glacial sediments was explored using groundwater numerical simulation. Numerical groundwater models have been used for studying variety of processes within and around aquifers, e.g. groundwater-surface water interactions, transport of

contaminants, etc. Numerical simulation of groundwater flow system refers to the construction and operation of a model whose behavior assumes the appearance of the actual aquifer behavior (Mercer and Faust, 1981). The modeling process involves (1) formulation of a conceptual model which is the understanding of the physical behavior of the modeled system; (2) developing mathematical equation which consists of the general partial differential equations and boundary and initial conditions describing the system; and (3) solving the general equation analytically or using numerical methods.

The mathematical equation for three dimensional movement of groundwater through porous media is described by partial differential equation (McDonald and Harbaugh,

1988):

(3)

Where kXX, kyy and kzz are values of hydraulic conductivity along the x, y, and z coordinate axes, which are assumed to be parallel to the main axes of hydraulic conductivity (Lt-1); h is the hydraulic head (L);

W is a volumetric flux per unit volume and represents sources and/or sinks of water (t-1);

-1 Ss is the specific storage of the porous material (L ); and t is time (t).

This equation describes ground-water flow under non-equilibrium (unsteady) conditions in a heterogeneous and anisotropic medium. Simply, the solution to the above equation

gives distribution of hydraulic head over time and space, i.e. (h, x, y, z, t) and it measures the rate and volume of water in storage. However, for a steady state simulation which is the case for this study, the change in head with time (∂h/∂t = 0) in the right side of the equation becomes zero. Thus, equation (3) can be simplified into the form:

(4)

Equation (4) has the same form as equation (3), except hydraulic head is only space- dependent, i.e. (h, x, y, z). Unsteady (transient) conditions are commonly used to simulate the aquifer behavior with time varying conditions such as pumping. In this study, a steady state numerical simulation was conducted using Modular Groundwater

Flow Model (MODFLOW). The entire modeling process was developed using GMS

(Groundwater Modeling System) software version 5.1, which has MODFLOW 2000 incorporated in it. GMS supports MODFLOW as a pre- and post-processor. The input data and the conceptual model for MODFLOW were prepared and generated by GMS and were converted into files that can be read by MODFLOW when MODFLOW is launched. The output from MODFLOW was then imported into GMS for post-processing.

MODFLOW is a 3D, cell-centered, finite difference, saturated flow model developed by the United States Geological Survey (McDonald & Harbaugh, 1988). MODFLOW solves the groundwater flow equation using a finite-difference method. MODFLOW (2000) has various packages which are used to solve equations for different problems. The most important packages used in this study are:

 Basic package: Used to specify the grid dimensions, the computational time

steps, define which cells are inactive and which cells have constant heads and an

array identifying which packages are to be used;

 Output control: Controls what information is to be output from MODFLOW and

when it is to be output;

 Layer Property Flow package (LPF): Performs the cell by cell flow calculations.

The input to this package includes layer types and cell attributes such as storage

coefficients and transmissivity;

 Recharge package: Simulates recharge to the groundwater from precipitation;

 Drain package: Simulates drain type boundary conditions;

 Preconditioned Conjugate Gradient package (PCG2): an iterative solver based on

the preconditioned conjugate gradient technique.

In addition, other modules of GMS such as Map (coverage), GIS, TIN, Borehole, and Grid modules were used in the pre- and post-processing. These include preparation of input data, construction of conceptual model and output formatting.

2.4.2. Finite difference approximation

Solving equation (3) or (4) is seldom possible in real situation with a complex and layered system of aquifers, except in very simplified systems like one dimensional flow simulation. However, it can be solved by numerical approximation using computer.

Finite difference approximation involves discretizing the continuous model domain into rows, columns and layers which give small units called cells. Each cell has a point where head will be calculated is called node (Figure 2.3). Columns

∆Ci Rows

Nodes ∆R j

Figure 2.3 Cells showing nodes and cell notations

Considering six surrounding cells of a given cell (Figure 2.4), the governing equation for groundwater flow in finite difference approximation for that cell (I, j, k) is given as

(McDonald and Harbaugh, 1988):

(5)

Where, is head at cell i,j,k and time step m (L);

CV, CR, and CC are hydraulic conductance between node i,j,k and a neighboring node

(L2/T);

2 is the sum of coefficients of head from source and sink terms (L /T);

is the sum of constants from source and sink terms, with < 0.0 for flow out of

3 the groundwater system, and > 0.0 for flow into the groundwater (L /T);

-1 is the specific storage (L );

is the cell width of column j in all rows (L);

is the cell width of row i in all columns (L);

is the vertical thickness of cell i,j,k (L); and tm is the time at time step m (T).

Figure 2.4 A given cell i,j,k with six surrounding cells (Modified from McDonald and

Harbaugh, 1988)

Equation (5) can be used as the basis for simulation of the partial differential equation of groundwater flow, equation (3). Like the term Qi,j,k, the coefficients of the various head terms in equation (5) are all known, as is the head at the beginning of the time

m step, . The seven heads at time t , the end of the time step, are unknown; that is, they are part of the head distribution to be predicted (McDonald and Harbaugh, 1988).

Equation (5) is an equation with seven unknowns for a single cell. When we write an equation for all n cells within the model domain, we have n unknowns (which are head

within each cell: ) and n equations which can be solved simultaneously.

All the known parameters such as conductance, and sources and sinks will be defined in the process of building the conceptual model. Not all cells have to be calculated in the process, some of the cells were defined before calculation as boundary conditions.

These are no-flow cells (water can’t pass through the cell); specified or constant head cells (head is fixed in this cell through the whole process); and/or variable head cells

(those cells where head to be calculated). Defining the boundary condition largely simplifies the simulation or calculation process.

2.4.3. Model design and model layers

The model area was discretized into regular sized cells of 50m by 50m with 80 rows and

120 columns. The total number of cells is 57,000 out of which 32,600 cells are active and

the remaining are inactive or no flow cells. The model grid is rotated by 150 toward

Northwest to align the cells perpendicular to specified flux boundaries. The model is bounded by the ground surface on top and by impermeable layer at the bottom. The model has six layers, as defined in the conceptual model. These are:

 Layer 1: The low permeability material (till);

 Layer 2: Sand and gravel materials of the buried valley (Outwash);

 Layer 3: The Pottsville Formation which contains mainly Sharon Sandstone and

Conglomerates;

 Layer 4: Cuyahoga Group which is dominantly shale with thin interbedded

sandstone;

 Layer 5: Berea Sandstone

 Layer 6: Pre-Berea formations.

The total model area is about 24 km2. The elevation ranges from 270m at the bottom layer to 390m on the top glacial drift. Each layer representing the hydrostratigraphic units was defined in the model as an array of top and bottom elevations. The bottom and top elevation of each layer was constructed using geostatiscal analyst tool in

ARCGIS. First, layer elevation from known points, wells, were extracted and then interpolated to produce continuous elevation surface or grid map. In this way, grid based maps with similar cell size as the model were prepared for all layers and imported into GMS. These were used to define the MODFLOW layers elevation arrays and then to

model the overall geometry. The top most elevation is the elevation of the ground surface which was extracted from USGS DEM.

The top three layers (till, sand & gravel and Pottsville Formation) were considered unconfined to semi-confined aquifers and simulated as convertible option in LPF (Layer

Property Flow) package. This allows the aquifer to be convertible between confined and unconfined condition depending on the hydraulic head. Cuyahoga Group (layer 4) was taken as a confining layer whereas Berea Sandstone was simulated as a confined aquifer.

2.4.4. Hydraulic conductivity and anisotropy

Hydraulic conductivity and anisotropy values were considered for each model layer. The

MODFLOW, LPF package has an option to assign the array values of hydraulic conductivity, vertical and horizontal anisotropy for each layer. Vertical anisotropy, which is the ratio of the horizontal to vertical hydraulic conductivity, was considered for layers where vertical fractures were expected. Vertical fractures were reported by various researchers in the glacial sediments and Pottsville Formation. Most of the aquifer tests conducted in Pottsville Formation showed that the wells were completed in fractures and joints. These fractures and joints have been enlarged by weathering if they are near the surface (Baker, 1964). Thus anisotropy, which is the ratio of horizontal to vertical

hydraulic conductivity, of 1/3 was assumed for simulation of the Pottsville Formation

(layer 3). Berea Sandstone, where it is found at depth, is less fractured and thus vertical anisotropy was ignored. The buried valley deposit, composed of unconsolidated material of sand and gravel, was assumed isotropic.

Hydraulic conductivity values were assigned to each layers based on calculated values

(for the case of buried valley sediments) and reviewed values of previous work for bedrock materials. Initially, for the low permeability material of the glacial drift (layer 1), an average published value of 4.0E-04m/day was considered for horizontal hydraulic conductivity (Figure 2.5) and was assumed vertically isotropic. For the case of sand and gravel, a range of values from 1 m/d to 20 m/d was taken based on the calculated values. Regarding the bedrock formations, average values collected from various researchers was used such as 1 to 20 m/d, 4.0E-05 m/d, 2 m/d for Pottsville Formation,

Cuyahoga Group and Berea Sandstone respectively. These are initial values, which later would be changed in the calibration process. The bottom layer (pre-Berea formations), which is insignificant with regard to productivity, was considered an impermeable boundary. Thus, a very low hydraulic conductivity (10-7 m/day) was given to simulate this condition (summarized in Table 2.2).

Figure 2.5 Published values of hydraulic conductivities from Halford and Kuniansky

(2002) and Domenico and Schwartz (1990) as in Freeze and Cherry (1979).

2.4.5. Boundary conditions

Accurate definition of boundary conditions is an essential part of conceptualizing and modeling groundwater systems. It is a part of the process of the mathematical model and it is simply defining the boundary cells of the model with mathematical expression.

Defining a boundary condition involves a careful understanding of the physical system and considerable simplification of the hydrogeologic conditions. The boundary condition is usually specified in terms of the dependent variable, head or it can be also determined using flow. A given boundary can be a specified head, specified flow or head

dependent flow boundary depending on the physical or hydraulic condition. Two types of boundaries were defined in this model layers. No flow boundary which is a special type of specified head boundary where there is no flow across the boundary

. The second type of boundary is specified flow boundary where

there is quantitatively defined flow across the boundary.

No flow boundary

As shown in Figure 2.6, for all model layers, no-flow boundary condition was assigned to the top and bottom sides of the model area. The top and bottom boundaries of the area were overlapped with the surface water divide or surface drainage boundary. This is based on the assumption that the shape of the groundwater level is a replica of topography, a no flow groundwater boundary was assigned for all layers along this watershed divide.

NFB

Bedrock

NFB NFB

FAB

Buried valley

FAB

Flow lines

Equipotential lines

Bedrock NFB

NFB NFB: No flow boundary

FAB: Flow across the boundary NFB

Figure 2.6 Schematic map view representation of boundary conditions in the bedrock units and buried valley sediments of the glacial drift

As shown in Figure 2.6, the top and bottom sides are the bedrock units whereas the buried valley is found at the middle. Water level maps of the bedrock aquifers indicated that groundwater flow from the bedrock aquifers toward the buried valley and the flow lines (blue arrows) are parallel to the up and down stream boundaries of the area (left and right side on the map). Thus, the up and downstream side boundaries of the bedrock units were assigned no-flow boundaries, this is because there is no flow crossing these boundaries.

Table 2.2 Summary of initial model parameters

Model layer Initial Kh Anisotropy No. Unit (m/d) (Kh/Kv) Type 1 Till 4.00E-04 1 Sand and gravel Unconfined to 2 (Outwash) 1 - 20 1 Semi-confined 3 Pottsville Formation 1 - 20 0.3 “ 4 Cuyahoga Group 4.00E-05 1 Confining layer 5 Berea Sandstone 2 1 Confined 6 Pre-Berea Formations 1.00E-07 1

Specified flow boundary

Specified flow boundary can be used where there is a flow across the boundary. Here, specified head can be also used. However, giving a constant head along the boundary results in fixing the head for the whole period of simulation, which controls the simulation result. Instead, a specified flow was used to let the model specify the head for the boundary. As shown in the map (Figure 2.6), there are inflows and outflows in the buried valley sediments. Simulating specified flow requires an estimate of inflow and outflow across the boundary. The amount of inflow and outflow were estimated using Darcy’s equation (Q=KAi). First, the gradient (i) was determined along the boundary from the water level map. The cross-sectional area (A) perpendicular to the gradient was calculated from the model cross-section by simply summing up the cells perpendicular to the flow direction. The estimation was done using Darcy's equation,

where k is taken from the hydraulic conductivity map of buried valley sediments. It is assumed that inflow and outflow occurs only through the drift sediments. The estimation of the rate of inflow and outflow (Q) are tabulated in the appendix III. The estimated total rate of inflow toward the model was 2000 m3/day whereas the outflow from the model domain was 6000 m3/day. These rates are attributed to both layers; the till (layer 1) and the sand and gravel (layer 2). Assuming that the majority of the flow occurs through the high permeability materials (layer 2), >90% of the amount from the total in and out - flow was given to layer 2 (Outwash). The remaining was given to the specified flow boundary of layer 1 (till). These values were later adjusted during the process of calibration. The grid design and boundary conditions for all layers is shown in

Figure 2.8.

2.4.6. Drain boundary

The Drain package is used to simulate the effect of drains on an aquifer. Drains remove water from the aquifer as long as the water table is above the elevation of the surface. If the water table falls below the elevation of the drain, the drain has no effect. The drainage receives water from the groundwater, it doesn’t recharge the groundwater.

The rate of removal is proportional to the difference in elevation between the water table and the drain. The constant of proportionality is the conductance of the fill material surrounding the drain (EMRL, 1999).

Usually, rivers which receive baseflow from the groundwater are simulated using this package. According to Eberts, Bair and De Roche (1990), in northeast Ohio, most of the rivers are receiving recharge from the groundwater flow. Thus, the river in the study was simulated as a drain boundary using the drainage package of MODFLOW. The inputs necessary for this simulation are the bottom elevation of the river bed and the river bed conductance. Elevation of the river bed was extracted from the DEM and was assigned to the nodes of the drain at the beginning and the end. The elevation assumed to be varying linearly between the nodes. The conductance determines the amount of water flowing from the aquifer through the river bed based on the head in aquifer. The river bed conductance is calculated using Darcy’s law.

Q = KA∆h/L Q – rate of flow; K – hydraulic conductivity; L-flow path length

A – Cross-sectional area and ∆h – head loss.

Where the term excluding ∆h in the right side is the conductance (C, m2/day): C = KA/L.

In this case, K is the hydraulic conductivity of the river bed material, and flow length (L) is equal to the thickness of the river bed material (t) and area (A) is width (W) multiplied by length of the river bed (L) (Figure 2.7). However, GMS automatically calculates the length of the drain from the river arc and multiplies it with the conductance. Therefore, when a conductance is assigned for an arc, it should be in terms of conductance per unit length which is equal to K*W/t. Grasso (1986) observed silty river bed material for the

Chagrin River. So, a published value of 1 m/day of hydraulic conductivity (Figure 2.5) and

estimated 1m thickness of the river bed was assumed. Width equal to 20m was approximated from the DEM. Thus, the conductance per unit length of 20m2/d was used as an initial value to simulate the drain.

River bed

Figure 2.7 Schematic representation of a drain in a single cell

2.4.7. Recharge boundary

Recharge was simulated as an aerially distributed recharge that percolates into the groundwater. Recharge in MODFLOW is simulated by Recharge Package. The recharge

3 -1 flow rate (QRi,j) applied to the model at a horizontal cell location i, j (L T ) is given by

(McDonald and Harbaugh, 1988):

QR i, j = Ii, j * ∆Rj * ∆Ci

-1 Where Ii, j is recharge flux (LT ) and ∆Rj & ∆Ci are the cell dimensions. The recharge is applied to a single cell within a column and only applied to the top most cells, because the groundwater percolation occurs from the top surface. As discussed in section 2.3.3,

recharge to the groundwater was estimated by various researchers. Since the area is mostly covered by the glacial sediment, average recharge flux value was taken for the entire area. During simulation, recharge was varied within ranges from 4.0E-4 m/day to

6.0E-4 m/day.

Layer 1 (top layer) Layer 2 Layer 3, 4, 5 & 6 (all the same boundary)

Specified flow boundary

Drain boundary

No flow boundary

Figure 2.8 Boundary conditions of all model layers and grid design

2.4.8. Calibration

In order for the groundwater model to be used for the intended purpose, it must be demonstrated that the model successfully represent the aquifer behavior, and this is achieved by calibration. Model calibration is a process of modifying input parameters to a groundwater model until the output data (model computed) from the model matches observed data (field measured). The modified parameters can be hydraulic conductivities and recharge rate which will be varied until the calibration targets such as model head and/or flows matches the observed values. The quality of the calibration would be more enhanced if the combinations of the head and flow parameters are used. The values of the parameters that are going to be adjusted should be in the acceptable ranges of observed values during the calibration process. For instance the calibrated hydraulic conductivity of a given layer is less likely to be out of the range of values of observed hydraulic conductivity of that layer, otherwise it becomes far from the real condition.

A model can be calibrated by trial and error approach or using automatic calibration tools. Trial and error approach, which is the most commonly used (if somewhat tedious) method, involves changing values of parameters and running the model repeatedly till the computed values approach the observed within an acceptable range of accuracy. On the other hand, automatic calibration uses model external utilities which set bounds on

parameters while minimizing the discrepancy between model results and field observations. Automatic calibration is quick and gives more reliable results over the trial and error method. PEST, MODFLOW 2000 PES and UCODE are automated parameter estimation utilities based on inverse modeling which are provided in GMS. Calibrating the model using automatic method was attempted several times, but the model couldn’t converge or crashed in the process of parameter estimation. This might be due to the nature of the model which has complex layers, multiple variables and the presence of dry cells in the top layer which was the case in the unconfined aquifer and makes the model difficult to converge. It was found out that the automatic calibration is very efficient and quick to calibrate a simple model with small number of variables.

Similar opinions were presented by other researchers such as Martin and Frind (1998),

Gurwin and Lubczynski (2005). They suggested that complex models with well defined geologic and hydrogeologic structures were more efficiently calibrated with trial-and- error methods than with automatic optimization methods. Thus, the calibration was done using trial and error approach. This method is more powerful because expert judgment plays major role than in the process, whereas in automatic procedures calibration is restricted to a certain boundaries with limited number of variables.

The calibration parameters used were horizontal hydraulic conductivity, vertical anisotropy, recharge rates, drain conductance and rate of flow along the specified flow boundaries. These parameters were changed and the model was run repeatedly till the

calibration or computed heads and/or flows match with known values of heads and/or flows in observation points.

Observation points

A total of 23 observation points were used for calibration. 19 of them are water wells and the remaining 4 observation points are water levels along the river. The observation points include wells intercepting the major aquifers of the buried valley, Pottsville

Formation and Berea Sandstone, and the confining layer Cuyahoga Group. The points are spatially well distributed to represent the groundwater system effectively (see

Figure 3.12).

Drain

It was stated that the river crossing the area gets recharge from the groundwater which was simulated here as a drain. The amount of baseflow was estimated from the nearby station, near Chagrin Fall, found southwest of the study area. The 90% annual flow of the river at this station was equal to or greater than 0.209 cfs/sq. mi. or 1.97E-04 m/day/m2 (Schiefer, 2002). Based on this estimation, the study area approximately contributes 2560 m3/day of baseflow to the river. The drain conductance and the amount of outflow to the drain boundary were calibrated using a baseflow of approximately 2000 m3/day with ±500 m3/day interval. During calibration this value was

varied until the model result gave minimum percent discrepancy with respect to the overall water budget of the model.

Calibration targets

If an observed value has been assigned to an observation point, the calibration error at each point can be plotted using a calibration target. A set of calibration targets provides useful indicators of the magnitude, direction (negative or positive), and spatial distribution of the calibration error. The components of the calibration target are shown in the Figure below (Figure 2.9). The center point represents the observation value. The error is indicated by the box whereas the plus and minus intervals are shown by the whiskers.

Observed + interval Computed value

Error

Calibration target Observed value

Observed - interval

Figure 2.9 Components of calibration target

The calibration target interval was set based on the study by Jagucki and Lesney (1995).

According to the study, water level measurements from 1986 to 1994 indicated that

80% of the wells have shown a variation of ±1.5m from observed value. Thus, in this model 1.5m interval was taken for calibration with 80% of confidence.

Calibration measures and statistics

Several parameters are available to measure the agreement between the observed and model computed results. This is based on residual (Ri) which is the difference between model computed head or flow and observed head or flow. Mean residual ( ) which is the average of all the residuals (equation 1). Absolute residual mean | | is a measure of average absolute residual value (equation 2). The Root Mean Squared residual (RMS) and Normalized RMS (NRMS) are defined in equation (3) and (4) respectively.

...... (1)

...... (2)

...... (3)

...... (4)

Besides calculating the above parameters, graphs and maps were constructed to help visual interpretation of the calibration error. The other measure of adequacy of each model run during calibration is the percent discrepancy, which is the discrepancy of the

overall model mass balance. Discrepancy is the ratio of the difference between inflows and outflows with half of their sum. Ideally, to satisfy the total mass balance of the model, the discrepancy should be zero but not possible in reality. A very low percent discrepancy (less than 5%) was attempted during calibration.

2.4.9. Mass balance

Once the model is calibrated determining the water budget is possible on a cell by cell basis or zonal or the overall mass balance of the model as well. A calibrated model has information about head and hydraulic conductivity value for every cell in the model domain. So, using this information and Darcy’s equation, it is possible to determine the rate of flow between two adjacent cells or multiple cells. A steady state water balance was calculated for the entire model and for the buried valley sediments. The mass balance for each aquifer layer was also determined. The rate of flow between the major bedrock aquifers and buried valley aquifer was analyzed along the valley. The rate of flow along the depth of the sub-crop of bedrocks to the buried valley sediment was estimated on sections at different locations on a cell by cell basis. On each section, the flow from each cell interfacing the buried valley was determined and added up to get the net flow toward the buried valley on that section. The total contribution of the bedrock aquifers to the buried valley was estimated and compared with the total rate of inflow to the buried valley.

CHAPTER 3

RESULTS

3.1. Stratigraphy and hydrostratigraphic units

Various sections, thickness maps and 3D model were used to simplify and visualize the geometry of the aquifer systems in the area. The materials found in the study area included glacial sediments and bedrock units. The glacial sediments were grouped into two categories: till and outwash deposits. The till contains unsorted clastic materials with substantial quantities of clayey material, which was characterized as low permeability material. Driller’s log units described as clay, silty clay, sandy clay, puddle clay, clay with sand and gravel, dirt, top soil, hardpan, and mud were included in this group. It covers the top most part of the area which is underlain by the outwash in buried valley and by bedrock units on the uplands. Its thickness reaches up to 70m where it is thick in the hills and thin in the buried valley, specifically near the river

(Figure 3.1). None of the wells tap water from this material.

The outwash (sand and gravel material), the second group of the drift sediment, is characterized by coarser and better sorted clastic materials found in the buried valley.

Driller’s log descriptions like silt, sand, sand and gravel, silty sand, gravel, broken rocks,

quick sand, drift sand, boulder, etc were included in this group. It is thick toward the center of the valley. The axis of the valley doesn’t overlap with the current river course which indicates that the river might follow different courses in the past. The thickness of this material reaches 40m near the central part of the study area. This material constitutes a good source of groundwater of the water wells tapping this aquifer in the lowlands of the study area. Elsewhere the sand and gravel may be found as thin layers alternating with the clayey material. However the productivity of such formations is very low due to the presence of clay materials.

Figure 3.1 Isopach maps of various units

The bedrock units include the Pottsville Formation, the Cuyahoga Group and the Berea

Sandstone. In most of the lithological logs, the Pottsville Formation was described as sandstone and conglomerates with thin layers of shale. The shale layer was observed in small number of wells. The Pottsville Formation is found in limited area capping the uplands (Figure 3.3 and 3.4). It is a good source of groundwater at shallow depth.

Figure 3.2 Isopach map of Berea Sandstone

The Cuyahoga group is mainly composed of shale with thin layers of fine sandstones. It is the thickest rock unit in the area which ranges from 25 - 55m. There were some wells penetrating this rock unit but gaining very low yield. As observed in some of the driller’s log, water is intercepted along the contacts between shale and thin sandstone layers.

Till Outwash (sand and gravel) Pottsville Formation Cuyahoga Group Berea Sandstone Pre-Berea Formation

Figure 3.3 Three dimensional hydrostratigraphic model

The bottom hydrostratigraphic unit in the study area is the Berea Sandstone. It ranges in thickness from 12 to 20m. There are wells penetrating this layer in places where the upper aquifer layers are thin or absent. Generally, on the valley side all the bedrock units subcrop under the till and outwash sediments. From the well data, it was observed that the Pottsville Formation and Outwash were found to be in unconfined condition.

The water level is generally corresponding to the top elevation of these layers.

Elsewhere the till acts as a confining layer. However there are areas where the till is fractured and in this case, the underlying layer would be still an unconfined aquifer. The

Berea Sandstone is generally found to be in a confined condition except in areas where the confining layer, Cuyahoga Group is absent.

Layering along model column 24 Layering along model column 34

Layering along model column 44 Layering along model column 54

Layering along model row 39 Layering along model row 49

Layering along model row 69 Layering along model row 59

Layering along model row 83 Layering along model row 96

- Till - Outwash (Sand and Gravel) - Pottsville Formation - Cuyahoga Group - Berea Sandstone - Pre-Berea Formation

Figure 3.4 Layering along different model rows and columns (vertical exaggeration = 10)

3.2. Hydraulic parameter estimation of the buried valley sediments (Outwash)

A total of 68 pumping test data of water wells penetrating the buried valley sediment were used to determine the hydraulic properties. These wells penetrated the sediment at variable depth and the pumping tests were conducted for varying pumping time ranging from 1hr to 72 hrs. The pumping rates ranged from 10 to 1380 m3/day and drawdown from 1 to 32m. The observed specific capacity data were found to be in the range of 0.5 to 150 m3/day/m, While, the corrected (for partial penetration) specific capacity values ranged from 10 to 4560 m3/day/m. The data is summarized in Table 3.1.

Table 3.1 Summary of observed and corrected specific capacity data

Observed Pumping Draw Sp. Cap. Drawdown Sp. Cap. rate, Q down, so Observed corrected Corrected 3 3 3 (m /day) (m) (m /d/m) sc (m) (m /d/m) Mean 117.30 11.72 18.64 0.54 488.71 Standard Error 19.80 1.11 2.76 0.06 81.83 Median 109.04 9.14 11.07 0.31 274.58 Mode 109.04 6.10 35.77 0.30 1,352.40 Standard Deviation 163.31 9.12 22.73 0.49 674.81 Sample Variance 26,671.57 83.18 516.67 0.24 455,371.63 Minimum 10.90 0.91 0.58 0.03 10.02 Maximum 1,379.36 32.61 150.85 2.30 4,562.09

3.2.1. Correction for partial penetration

As shown in Table 3.1, there is a big difference between the observed and corrected values of drawdown and/or specific capacity. This big difference between the corrected and observed values comes from the effect of partial penetration of the wells to the aquifer. On average, about 95% of the drawdown attributed to the effect of partial penetration. The removal of the effect of partial penetration from the drawdown resulted a substantial increase in the corrected specific capacity values.

Table 3.2 Summary statistics of the estimated transmissivity and hydraulic conductivity

Log (T) Log (k) T (m2/s) T (m2/d) K (m/s) K (m/d) Mean (Geometric) -3.53 -4.80 2.94E-04 25.40 1.57E-05 1.35 Standard Error 0.05 0.06 Median -3.49 -4.76 Standard Deviation 0.42 0.48 Sample Variance 0.18 0.23 Kurtosis -0.14 -0.53 Skewness -0.25 -0.17 Range 2.08 2.03 Minimum -4.68 -5.92 2.07E -05 1.8 1.21E -06 0.10 Maximum -2.61 -3.88 2.48E-03 214.0 1.31E-04 11.32 Confidence Level (95.0%) 0.10 0.12

3.2.2. Transmissivity and hydraulic conductivity analysis

Very small values (near zero) of skewness and kurtosis (Table 3.2), as well as visual interpretation indicated that the calculated transmissivity and hydraulic conductivity values for the outwash were found to be log-normally distributed (Figure 3.5). The summary statistics of the log-transformed values of transmissivity and hydraulic conductivity is shown in Table 3.2. Estimated transmissivity values range from 2E-05 to

2.5E-03 m2/s with a geometric mean of about 3E-04 m2/s (≈25 m2/d). The estimated value of hydraulic conductivity range from about 1.2E-06 to 1.31E-04 m/s with a geometric mean of 1.57E-05 m/s (≈1.4 m/d). A wide range of estimated values can be attributed to the variable nature of the lithology, thickness and spatial heterogeneity of the material (The overall calculation of the hydraulic parameters is found in Appendix

IV)

(a) 20 25 (b) 16

15 12

10 8

Frequency Frequency 5 4 0 0

Log (T) Log (k)

Figure 3.5 Histograms of estimated transmissivity, T (a) and hydraulic conductivity, K (b) for sand and gravel aquifers of the glacial drift

3.2.3. Spatial distribution of hydraulic parameters

The hydraulic parameters in the outwash are highly variable. The lateral variations do not have any clear pattern but higher values of transmissivity are located in the central part of this deposit (Figure 3.6). Estimated value in the central part of the buried valley has a geometric mean of transmissivity about 32 m2/d while the values in the northern periphery have a geometric mean of 14 m2/d. The transmissivity values in the southern part of the area have a geometric mean of 25 m2/day. The outwash in the southern part is relatively thicker than the northern part of the area which contributes to the higher transmissivity value. The central part has relatively thick sediments and might have relatively clean sand and gravel. It probably indicates that the ancient channel followed a path near the central part of the buried valley.

Figure 3.6 Distribution of estimated transmissivity values

3.3. Conceptual groundwater model

The only source of recharge to the groundwater in the area is precipitation. Recharge occurs through the glacial sediments and Pottsville Formation. Groundwater is discharged into rivers and other surface waters. The Upper Chagrin River crossing the area is gaining water from the aquifers. Lateral groundwater exchange between aquifers occurs at the interface between glacial buried valley sediments and the surrounding

bedrock subcrops. Three major aquifers were identified in the area: the Pottsville

Formation, sand and gravel (Outwash) and the Berea Sandstone.

Water level surface in m

Figure 3.7 Groundwater level map and flow direction in the upper aquifers: Pottsville

Formation and sand and gravel (Outwash) of the buried valley

Groundwater level and flow direction

Two groundwater level maps were constructed by interpolation of the water level elevation in wells from the study area: (1) for the upper aquifers which includes the

Pottsville Formation and the Outwash (Figure 3.7) and (2) for Berea Sandstone (Figure

3.7). The groundwater level in the upper aquifers more or less follows the shape of topography where it is higher in the uplands and lower in the valley. Groundwater generally flows from the uplands toward the valley. In the uplands, the groundwater flow has a radial pattern of a recharge area (Figure 3.7). In the lower aquifer (Figure 3.8), the potentiometric surface has a similar pattern as the upper aquifers’ water level and the general pattern of flow is toward the valley. Accordingly, groundwater flow from the bedrock units toward the buried valley sediment.

Potentiometric surface in m

Figure 3.8 Potentiometric surface map and flow direction in the lower aquifer: Berea

Sandstone

3D (Figure 3.9) and 2D (Appendix II) conceptual models were constructed showing the topography, hydrostratigraphic units, and groundwater level and flow direction. Aside from the obvious lateral flow within the formations there is a distinct vertical to sub- vertical flow (Figure 3.9), most notably through the fractures within the Cuyahoga Group into Berea Sandstone. Groundwater from the bedrock units locally flows toward the buried valley sediments. Regionally, groundwater flows to the southwest part of the area.

Till

Sand and gravel

Pottsville Formation

Cuyahoga Group Berea Sandstone Groundwater flow

Figure 3.9 Three dimensional conceptual model showing the groundwater flow in the bedrock units and drift sediments 78

3.4. Numerical Model Calibration

Based on the conceptual model, the numerical groundwater model was constructed and calibrated through a series of model runs. During calibration, the model was run about more than 500 times with changing parameters within reasonable limits until the calibration targets, such as discrepancy and residual head interval, were satisfied.

Hydraulic conductivity, vertical anisotropy, recharge, drain flows and conductance were the parameters which were adjusted to reproduce the observed head and flow values.

The summary statistics of the calibration is shown in Table 3.3. The average residual head is 0.31m (≈1ft) and the Root Mean Squared (RMS) residual is nearly 1m. The

Normalized RMS of the residual heads is 2.5 percent. The sum of squared weighted residual of both head and flow is 26.

Table 3.3 Summary statistics of calibration

ITEM Value Mean Residual (Head) in m 0.31 Mean Absolute Residual (Head) in m 0.90 Root Mean Squared Residual (Head) in m 1.10 Normalized RMS (%) 2.50 Mean Residual (Flow) in m3/day -39.07 Absolute Residual (Flow) in m3/day 39.07 Root Mean Squared Residual (Flow) in m3/day 39.07 Mean Weighted Residual (Head+Flow) 0.17 Mean Absolute Weighted Residual (Head+Flow) 0.81 Root Mean Squared Weighted Residual (Head+Flow) 1.05 Sum of Squared Weighted Residual (Head+Flow) 26.21

The observed and calibrated data is summarized in appendix V. A graph showing the fit between the observed and computed head is shown in Figure 3.10. The correlation coefficient between the observed and computed head is 0.998 and R2 is equal to 0.996.

Observed Vs Computed head

360.0

350.0 R² = 0.996

340.0

330.0 Computed head (m) head Computed

320.0

310.0 310 320 330 340 350 360

Observed head (m)

Figure 3.10 Model computed versus observed head data (23 samples)

Figure 3.11 shows the range values of residual heads along with the observed head values. Most of the computed heads (> 80%) were within ±1.5m interval from the

observed values. Forty five percent of the computed heads were found within ±0.5m interval and 65% of were within ±1.0m from the observed values.

Observed Vs Residual head 3.00

2.00

1.00

0.00 310 320 330 340 350 360

-1.00 Residual head (m) head Residual

-2.00

-3.00 Observed head (m)

Figure 3.11 Observed heads versus residual heads.

Figure 3.12 Spatial distributions of the calibration targets (see Figure 2.9 for legend).

3.5. Numerical Model results

Several types of information can be extracted from a calibrated model. Here, (1) simulated hydraulic parameter values; (2) hydraulic head values and distribution for each model layers; (3) overall model mass balance; and (4) mass balance of the buried valley aquifer and flux between the bedrock aquifers and buried valley aquifer were estimated.

3.5.1. Simulated hydraulic parameters

The simulated hydraulic parameter results include hydraulic conductivity and vertical

anisotropy values of each layers, river bed conductance and recharge. The last two

parameters were simulated for the top layer, till. The range of values of simulated

hydraulic parameters is summarized in Table 3.4.

Table 3.4 Simulated hydraulic parameter values

Hydraulic Geometric River bed Conductivity Mean Vertical Conductance Recharge Unit (m/day) (m/day) Anisotropy (m2/d/m) (m/day)

Till (layer 1) 0.008 - 0.5 3.5 5.50E-04

Drift Drift

Sediments 19.5 Sand and gravel (layer 2) 15.0 - 25.0 1.0 1.1 Pottsville Formation (layer 3) 0.25 - 2.50 0.4 - 0.5 Cuyahoga Group (layer 4) 0.0001 - 0.001 0.0002 0.3 - 0.5

Berea Sandstone (layer 5) 1.9 - 1.0 Bedrocks Pre-Berea Formation (layer 6) 1.00E-07 - 1.0

The simulated hydraulic conductivity values were used to determine the transmissivity

of the aquifers which is the product of hydraulic conductivity and aquifer thickness or

saturated thickness of the aquifer depending on the type of aquifer. Specifically,

transmissivity is determined for the sand and gravel, Pottsville Formation and Berea

Sandstone (summarized in Table 3.5). The range of simulated values of transmissivity of

the buried valley aquifer is from 5.2E-04 m2/s (45 m2/d) to 1.3E-02 m2/s (1095 m2/d)

with a geometric mean value of 4.0E-03 m2/s (350 m2/d). A log transformed interpolation map showing the spatial distribution of transmissivity values is shown in

Figure 3.13.

Table 3.5 Model simulated layer transmissivity values

Minimum Maximum Geometric Layer (unit) (m2/d) (m2/d) mean (m2/d) Sand and gravel (Outwash) 45 1095 350 Pottsville formation 10 75 27 Berea Sandstone 18 40 30

Figure 3.13 Model simulated transmissivity distribution in the sand and gravel

(Outwash) aquifer.

3.5.2. Simulated hydraulic heads

Hydraulic heads were calculated for every active cell in the model domain. Maps were constructed for each layers showing the hydraulic head distributions (Figure 3.14).

Hydraulic head distribution in Hydraulic head distribution in layers 1, 2, 3 layer 4 (Cuyahoga Group) (Sand and gravel and Pottsville Formation)

Hydraulic heads (m)

>355 350 - 355 345 - 350 340 -345 335 - 340 330 - 335 325 - 330 320 - 325 315 - 320 310 - 315

Hydraulic head distribution in layer 5 (Berea Sandstone)

Figure 3.14 Maps showing hydraulic heads in model layers

Profile sections were also made across the buried valley to show the head and flow

directions (Figure 3.15). In the figure, hydraulic potentials are represented by blue lines

and a model generated flow directions are shown by blue arrows.

Till

Berea S.

Model column 21

Pottsville F.

Sand and Gravel

Model column 28

Cuyahoga G.

Model column 33

Model column 37

Figure 3.15 Model sections showing hydraulic head and flow directions

Layer 2 (Sand and Gravel) Layer 3 (Pottsville Formation)

Layer 4 (Cuyahoga Group) Layer 5 (Berea Sandstone)

Figure 3.16 spatial distributions of model generated flow directions (blue arrows indicate the direction)

The spatial distribution of groundwater flow in each layer was generated using the hydraulic heads of each cell in the model layers. The maps (Figure 3.16) indicate the flow direction in the three aquifers (Sand and gravel, Pottsville Formation and Berea

Sandstone) and a confining layer (Cuyahoga Group). In the central part of the area which is identified by the buried valley material, groundwater flow from east to west or from upstream to downstream direction (layer 2 of Figure 3.16). In the bedrock aquifers which are indicated by layer 3 and 5 of Figure 3.16, flow is toward the central part. In layer 4, there are no arrows indicating flow direction, rather points which show groundwater flow in this layer is vertically downward.

3.5.3. Mass balance

The components in the water budget calculation are (1) direct recharge from precipitation to the upper most layer within the model, (2)flow across the upstream boundary (inflow to the model), (3) groundwater discharge (baseflow) to the river

(simulated as drain boundary) and (4) flow across the downstream model boundary

(outflow from the model). The overall mass balance is determined on a daily and yearly basis with a discrepancy of 3% (Table 3.6). Considering the entire model, about 87% of the inflow comes by recharge from precipitation and the remaining 13% comes from inflow from the upstream model boundary. About 78% of the total inflow flows out

across the downstream model boundary. The remaining 22% flows out the model domain in the form of baseflow to the river.

Table 3.6 The Entire model mass balance

IN IN OUT OUT IN OUT (m3/d) (%) (m3/d) (%) (Mm3/yr) (Mm3/yr) Flow across the boundaries 1098 13 -6883 -78 0.4 -2.5 Recharge 7477 87 0 2.7 0 Drains (discharge) 0 -1961 -22 0 -0.7 Total 8575 100 -8844 -100 3.1 -3.2 IN - OUT -269 -0.1 Discrepancy (%) 3.0

The flux along the contact between the bedrock aquifers and the buried valley aquifers is determined using the hydraulic data from the simulation. In cross-section, it was observed that both the Pottsville Formation and Berea Sandstone are feeding the outwash aquifer (Figure 3.17).

Pottsville F.

Cuyahoga G.

Sand and Berea S. Gravel

Figure 3.17 Flow directions (blue arrows) on one side of the interface between bedrock aquifers and sand and gravel aquifer (model column 38)

The mass balance of the buried valley aquifer shows that about 12,000 m3/d (4.2

Mm3/yr) groundwater flows toward this layer. This comes from recharge by precipitation; flux across the model boundary and from cells of adjacent model layers like the bedrock units and the overlying till material. About 1600 m3/d (≈0.6 Mm3/yr) groundwater flows from the bedrock aquifers (Pottsville Formation and Berea

Sandstone) toward the buried valley aquifer per km length of the buried valley; length measured along the stream. Considering the overall model, about 4400 m3/d (1.6

Mm3/yr) of groundwater is flowing toward the buried valley aquifer from the bedrock aquifers (Table 3.7).

Table 3.7 Data of the water budget in the buried valley sediment

In Out Flow Flow In Flow Out Flow (m3/d) (m3/d) (%) (%) Drain (discharge to the river) 0 1960 0 17 Flow across the model boundary 1015 7880 9 68 Recharge 5975 0 52 0 Pottsville 23 Bedrock Formation 2650 1800 15 aquifers Berea 15 Sandstone 1750 Total Flow 11390 11640 100 100 In - Out -250 % error -2.2

In addition, layer mass balance is calculated for comparison of each aquifer layers: the

Pottsville Formation, Outwash and the Berea Sandstone. Figure 3.18 illustrates the summary of the flux in the major aquifer layers (Table showing mass balance of each major aquifer layer is found in Appendix VI).

Outwash Pottsville Formation Berea Sandstone 4.8

3.6

2.4

Inflo

/yr) 3 1.2

0.0

-1.2 Rate of flow (Mm flow of Rate Outflow

-2.4

-3.6

-4.8 Zonal flow Source/sinks

Figure 3.18 shows the mass balance in each aquifer layers.

Chapter 4

Discussion

4.1. Hydraulic characteristics of the buried valley sediments

The ranges of values of transmissivity estimated from specific capacity data in this study were consistent with values estimated by various researchers in the vicinities of the study area, such as Richards (1981), ODC (1971), etc. The estimated transmissivity values range from 2 to 200 m2/d with a geometric mean value of 25 m2/d. ODC (1971) estimated transmissivity value of as high as 900 m2/d using time-drawdown analysis in the buried valley sediments of Cuyahoga River Valley. Richards (1981), using specific capacity data analysis, estimated hydraulic conductivity value as low as 0.25 and as high as 600 m/day. In this study, the estimated values of transmissivity are relatively lower than estimates by most of previous researchers, e.g. ODC (1971), Eberts, Bair and De

Roche (1990), and Richards (1981). The variation might be due to the heterogeneous characteristics of the glacial sediments. For instance, Robinson (1971) mentioned that the buried valley materials found in the Upper Cuyahoga River Valley has relatively more clayey material (silty sand and gravel) compared to the material in Chagrin River Valley.

Thickness of the aquifer which is variable from place to place, again determines the value of transmissivity which depends on the saturated thickness of the aquifer.

The depth penetration of the aquifer, duration of pumping test, and the use of various techniques of estimation of transmissivity can also contribute for the variation in values.

For instance, during the analysis, pumping tests conducted for a longer period of time gave fair values of transmissivity compared to those with short pumping time. This might be due to the availability of time to approach steady state pumping condition which can represent the aquifer behavior and actually gives fair result of transmissivity.

As described earlier most of the wells in this aquifer are, totally cased where a small portion of the wells is left open at the bottom, partially penetrating wells. Partial penetration of the aquifer causes a head loss as a result of the convergence of flow toward the well. The effect of partial penetration depends on the amount of penetration, screen length, thickness of the aquifer, pumping duration, measured distance from the well and aquifer anisotropy. The effect of partial penetration or the head loss from partial penetration is less for Longer pumping duration, larger screen length and larger thickness penetration. The opposite is true for the data in this study where most of the tests were conducted for short duration and most of the wells have small screen length and shallow penetration of the aquifer. As it is observed from the

analysis result of the removal of the effect of partial penetration, more than 95% of head loss (drawdown) is contributed by partial penetration.

4.2. Numerical model

A numerical model is built based on the conceptual model and calibrated using trial and error method with mean residual head error of 0.3m (≈1 ft). The correlation coefficient between the observed and model computed heads was 0.998. The Normalized RMS and model discrepancy are 2.5% and 3% respectively which are acceptable (less than 5%).

Model simulated parameters

The calibrated model provided simulated model parameters such as recharge, hydraulic conductivity or transmissivity values. The simulated recharge value (5.5E-04 m/d) is within the range of value of recharge (4.0E-04 to 6.0E-04 m/d) determined by various researchers, e.g. Pettyjohn & Henning (1979) and Richards (1981). Model simulated transmissivity values for the outwash, ranges from 45 to 1095 m2/d, is more consistent with values determined by ODC (1971) and Richards (1981). ODC estimated transmissivity values as high as 900 m2/d using time-drawdown analysis method. In this study, the model simulated values of transmissivity are higher than values estimated using specific capacity data analysis which ranges from 2 to 200 m2/d. Compared to the model simulated, the method of specific capacity analysis underestimated the range of

transmissivity values for the buried valley sediments. The highest transmissivity values for outwash are located in the central part of the valley.

The simulated hydraulic conductivity values for the Pottsville Formation range from 0.25 to 2.5m/d which is lower than previously estimated values. Richards (1981) estimated hydraulic conductivity values which ranges from 0.25 to 20 m/d and Maharjan (2011) also estimated hydraulic conductivity as high as 96 m/d for Sharon Sandstone in Geauga

County. However, in this study, vertical hydraulic conductivity was simulated for this unit by considering the vertical fractures present in this unit (Baker, 1964; Williams,

1983). As a result vertical hydraulic conductivity value as high as 6 m/d was simulated.

On the other hand, Berea Sandstone is simulated with hydraulic conductivity value of

1.9 m/d and it was considered vertically isotropic. Richards (1981) estimated hydraulic conductivity value for Berea Sandstone from 0.1 to 4 m/d and Rau (1969) estimated 2.5 m/d for this unit.

Groundwater flow

All the active cells in the calibrated model have calculated hydraulic head values which represents head in the aquifers. The hydraulic heads in the central part of the study area, which ranges between 310 to 325m, represent the head in the buried valley aquifer. On the other hand, the heads in the uplands represent the heads in the bedrock aquifers. Generally, there are two different water levels in the bedrock aquifers:

hydraulic heads in the Pottsville Formation which can reach up to 360m and the heads in the Berea Sandstone that can reach up to 330m. The Cuyahoga Group which is simulated as a leaky confining layer has hydraulic heads that ranges somewhere between the heads of the two bedrock aquifers. There is a large hydraulic gradient between the Pottsville Formation and buried valley aquifer. Relatively, low hydraulic gradient exists between the Berea Sandstone and the buried valley aquifer. The pattern of groundwater flow from the bedrock aquifers is generally toward the buried valley but there might be some local reversed flows depending on the local hydraulic gradient.

Flow reversal occurs between the Berea Sandstone and buried valley aquifer. Regional groundwater flow is generally toward the downstream direction.

The upper most model layer (till) and the Cuyahoga Group are leaky confining layers where groundwater flow is vertical and at rather low rates comparing with the flow in other units. The groundwater flow in the Pottsville Formation and Berea Sandstone are horizontal to sub-horizontal and directed toward the buried valley material. The

Pottsville Formation and the Outwash are found to be in unconfined to semi-confined aquifers.

Mass balance

There are two sources of groundwater inflows to the entire model domain: from recharge by precipitation and inflow across the upstream model boundary. The amount

of recharge is about 2.7 Mm3/yr and the amount of flux crossing the upstream boundary is about 0.4 Mm3/yr. Recharge is the only source of the groundwater in the area. The majority (≈80%) of the inflow, which is about 2.5 Mm3/yr, leaves the model across the downstream boundary. The remaining 0.7 Mm3/yr of water, which is nearly 20% of the total inflow, flows out in the form of baseflow to the river (Chagrin River) in the model area.

Regarding the mass balance of the buried valley aquifer, there is a significant amount of groundwater flow exchange occurred with the bedrock aquifers. Groundwater flows from the bedrock aquifers toward the buried valley sediment. Rate of flow analysis indicated that from the two bedrock aquifers a net 1600 m3/d (0.6 Mm3/yr) of groundwater flows toward the outwash aquifer per km length of the buried valley. 60% of the above amount is contributed by the Pottsville Formation and the remaining 40% of the flow comes from Berea Sandstone. Considering the entire model, about 4400 m3/d (1.6 Mm3/yr) of groundwater, which is ≈40% of the total inflow to the buried valley material (Figure 4.1), is contributed by the bedrock aquifers to the buried valley aquifer.

It is contributed by horizontal to sub-horizontal flow from the Pottsville Formation and

Berea Sandstone. The buried valley aquifer functions as drainage for the surrounding bedrock aquifers.

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Recharge (52%) Inflow Upstream (9%)

Outflow to the bedrock units (-15%) Discharge

Pottsville (Drain) (-17%) Formation

Cuyahoga Inflow from Shale the bedrock Buried valley aquifers (39%) Formation

Berea Sandstone Outflow Downstream (-68%)

Figure 4.1 Mass balance of the buried valley aquifer

Several factors control the amount of flux between the buried valley and bedrock aquifers such as hydraulic properties of the adjacent materials, the hydraulic gradient, and contact area. For instance, there is a high hydraulic gradient between the Pottsville

Formation and the buried valley aquifer compared to Berea Sandstone and buried valley aquifer. The contact surface area of the interface between the bedrock aquifers and the buried valley also determines the rate of flow. This area is a cross-sectional area

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perpendicular to the direction of the flow. There is a large contact surface area between the Berea Sandstone and buried valley aquifer. The Pottsville Formation which is found localized in the uplands has less contact area. Though the interface area is small, the large hydraulic gradient results in higher rate of flow or large contribution to the buried valley aquifer.

CHAPTER 5

SUMMARY AND CONCLUSION

The hydraulic properties of the buried valley material were assessed through conventional methods and numerical groundwater modeling. The basic data used was residential water well log reports which include lithological information and pumping test data. The lithological information contains the description of lithologies with depth for every well. This information was used to define the stratigraphy and then the hydrostratigraphic units. It was also used to build the 3D hydrostratigraphic model which was the framework for the numerical groundwater model. The pumping test information was used to characterize the hydraulic properties of the buried valley material by determining the transmissivity and hydraulic conductivity. It was also used to construct the groundwater level and flow direction. Selected water level information from this data was used for calibration purpose.

The uncertainty of building the 3D stratigraphic model from driller’s log depends on the quantity and quality of the well data. Regarding quantity, there were enormous amount of well data in the area. The lithological descriptions by drillers often vary from the descriptions found in textbooks on sedimentology; each driller has his own style of

102 103

description of the drill-cuttings; yet the mere density of the wells with lithological descriptions facilitated expert judgment about the spatial distribution of the lithological units. Standardization of well data is necessary to construct more accurate and reliable model, especially, in naming of lithological descriptions. However, the tools in GMS software enable the construction, 3D visualization and interpretation of the lithologies.

The specific capacity data from the driller’s report used to determine the values of transmissivity of the buried valley materials. The values were spatially highly variable and correlated with the lithology of the glacial sediments. The transmissivity analysis of the buried valley material gives ranges of values slightly different from values determined by previous researchers. This might be due to the nature of the material which varies from place to place, the type of pumping data used, and the assumptions and methods of analysis which were mainly based on empirical equations. If a time - drawdown data was available in the nearby wells from the same formation, the analysis from the specific capacity data can be correlated and calibrated as to give more reliable results.

A steady state numerical model which contains layers from the bedrock aquifers and drift sediment was constructed and calibrated satisfactorily using the available head and flow observations with mean residual error of 0.3m. The model gives very reasonable results on the simulated hydraulic parameter values such as the hydraulic conductivity values of the bedrock materials and drift sediment. The hydraulic head distributions

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calculated by the model indicated that there is a high hydraulic gradient between the bedrock aquifers and buried valley material. From all bedrock aquifers, groundwater flows toward the buried valley aquifer. The amount of groundwater flow toward the outwash aquifer from the bedrock aquifers is estimated by mass balance approach and shows that a significant amount of groundwater flow occurs from the bedrock aquifers to the buried valley. Hence the buried valley aquifer functions as drainage to the surrounding bedrock units.

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Eberts, S. M., Bair, E. S., and De Roche, J. T., 1990, Geohydrology, groundwater quality, and simulated groundwater flow, Geauga County, Ohio: USGS Water Resources Investigations Report, 90-4026, 117p.

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Kasenow, M., 1996, Production Well Analysis, new methods and computer program in well hydraulics: Water Resources Publications, 355 p.

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formations in Geauga County, Ohio: Kent State University, Master’s Thesis, 202p.

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APPENDIX

I. Cross-sections across the buried valley showing the various stratigraphic units

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Vertical Exaggeration = 15

Till, clay with silt, sand Pottsville Berea and gravel Formation Sandstone

Pre-Berea Sand and gravel (Outwash) Cuyahoga Shale Shale

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Vertical Exaggeration = 15

Till, clay with silt, sand Pottsville Berea and gravel Formation Sandstone

Cuyahoga Sand and gravel (Outwash) Pre-Berea Shale Shale

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Vertical Exaggeration = 16

Till, clay with silt, sand Pottsville Berea and gravel Formation Sandstone

Cuyahoga Pre-Berea Sand and gravel Shale Shale (Outwash)

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II. 2D conceptual model (Vertical exaggeration ≈ 10)

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III. Inflow-outflow estimation using Darcy’s Law

Inflow to the model via upstream boundary

3 2 Locations K (m/day) h2 (m) h1 (m) ∆h (m) L (m) Q/A (m /day/m ) 1 7.5 323.3 319.6 3.7 598 0.046 2 7.5 322.2 318.9 3.3 595 0.042 3 7.5 320.6 317.5 3.1 595 0.039 4 7.5 319.2 314.8 4.4 950 0.035 5 15 318.8 317.8 1 946 0.016 6 15 319.2 317.8 1.4 946 0.022 Average 0.033 Cross-sectional area (perpendicular to the flow direction) 55320 Total inflow (m3/day) 1843

Outflow from the model through the downstream boundary

3 2 Locations K (m/day) h2 (m) h1 (m) ∆h (m) L (m) Q/A (m /day/m ) 1 7.5 318.6 311.6 7 595 0.088 2 7.5 317.5 314.7 2.8 590 0.036 3 7.5 315.4 315.1 0.3 595 0.004 4 15 320 310.8 9.2 600 0.230 5 15 321 314.5 6.5 600 0.163 6 15 324.3 320.5 3.8 860 0.066 Average 0.098 Cross-sectional area (perpendicular to the flow direction) 61590 Total outflow (m3/day) 6019

IV. Calculation of the hydraulic parameters for the buried valley sediments Well_log T_depth SWL Observed Draw ID X Y Elev_m (m) Q (m3/sec) Q (m3/day) (m) down, so (m) time (hr) 388095 697134.3 204485.6 348.4 47 1.60E-02 1379.36 28.3 9.14 24 149067 697173.1 204166.1 340.9 47 1.26E-03 109.04 22.9 1.52 2 608985 697672.5 204141.7 332.0 30 6.94E-04 59.97 14.3 0.91 24 661013 699929.6 204224.5 323.5 27 9.47E-04 81.78 7.0 1.52 1 402398 699254.5 204922.4 335.4 46 1.58E-03 136.30 20.7 3.05 1 567957 696922.0 204098.0 338.2 37 9.47E-04 81.78 21.9 1.83 2 277534 697273.4 204077.8 333.6 59 6.31E-04 54.52 22.9 1.52 4 232049 696295.2 204317.8 331.0 31 1.26E-03 109.04 17.1 2.74 5 690994 697708.1 204111.8 328.3 24 1.26E-03 109.04 12.5 2.74 1 572017 698232.5 204727.5 336.3 27 1.26E-03 109.04 19.2 2.44 1 555929 699625.4 204444.0 331.6 33 1.58E-03 136.30 13.7 4.57 1 660978 699092.3 206045.2 349.4 54 1.26E-03 109.04 33.5 3.05 24 458356 697222.7 203014.0 322.8 14 1.26E-03 109.04 4.6 3.05 12 597395 696827.3 204487.2 342.0 55 1.26E-03 109.04 25.3 4.57 1 760861 699666.7 206188.1 345.3 58 8.20E-04 70.88 30.5 3.05 1 481994 699778.9 205205.4 326.8 27 1.58E-03 136.30 7.6 6.10 1 568163 698875.3 203590.3 346.1 17 7.57E-04 65.42 9.1 1.83 1 503763 699454.4 204768.8 324.5 23 1.26E-03 109.04 7.6 4.57 1 382030 699361.8 205073.2 325.3 20 1.58E-03 136.30 6.1 6.10 1 518554 696829.9 203705.8 326.6 35 1.26E-03 109.04 16.2 5.79 72 555521 699213.2 204918.9 337.9 43 1.26E-03 109.04 24.4 6.10 2 474974 698056.3 204176.8 329.6 37 4.42E-04 38.16 16.5 2.44 1 696949 697372.9 203703.8 333.9 31 6.31E-04 54.52 22.9 3.05 2 434093 698860.6 204948.5 342.6 50 6.31E-04 54.52 27.1 3.35 24 608974 696358.2 204095.7 332.1 48 7.57E-04 65.42 22.9 4.57 6 646370 696888.9 204327.5 345.3 55 1.14E-03 98.14 28.3 6.10 1

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...Continued laterally L, screen Aquifer Corrected Calc. Calculated Calc. Time length Sp. Cap Sc thicknessb drawdown Transmissivity Drawdown Transmissivity 2 2 (sec.) (m) (=Q/so) (m) L/b for pp. scorr Q/scorr (m /sec.) (m) T (m /day) 1440 0.3 150.8 35 0.009 0.3024 4562.09 2.48E-03 0.30235 213.96 120 0.3 71.5 35 0.009 0.0504 2163.84 1.72E-03 0.05039 148.58 1440 0.3 65.6 35 0.009 0.0302 1983.52 1.17E-03 0.03023 101.45 60 0.3 53.7 30 0.010 0.0588 1391.05 1.31E-03 0.05879 113.31 60 0.3 44.7 35 0.009 0.1008 1352.40 1.28E-03 0.10078 110.66 120 0.3 44.7 35 0.009 0.0605 1352.40 1.15E-03 0.06047 99.37 240 0.3 35.8 35 0.009 0.0504 1081.92 8.60E-04 0.05039 74.29 300 0.3 39.7 30 0.010 0.1058 1030.41 7.99E-04 0.10582 69.06 60 0.3 39.7 30 0.010 0.1058 1030.41 1.02E-03 0.10582 88.20 60 0.3 44.7 25 0.012 0.1114 978.82 9.78E-04 0.11140 84.52 60 0.3 29.8 30 0.010 0.1758 775.40 8.07E-04 0.17578 69.70 1440 0.3 35.8 25 0.012 0.1411 772.82 5.09E-04 0.14109 43.99

720 0.3 35.8 24 0.012 0.1454 750.04 5.40E-04 0.14538 46.68 60 0.3 23.8 35 0.009 0.1512 721.28 7.60E-04 0.15118 65.67 60 0.3 23.3 35 0.009 0.1008 703.25 7.44E-04 0.10078 64.32 60 0.3 22.4 35 0.009 0.2016 676.20 7.21E-04 0.20157 62.28 60 0.3 35.8 20 0.015 0.1049 623.77 6.75E-04 0.10488 58.29 60 0.3 23.8 30 0.010 0.1764 618.25 6.70E-04 0.17637 57.87 60 0.3 22.4 30 0.010 0.2352 579.61 6.35E-04 0.23516 54.90 4320 0.3 18.8 35 0.009 0.1915 569.43 3.43E-04 0.19149 29.60 120 0.3 17.9 35 0.009 0.2008 543.05 5.33E-04 0.20079 46.07 60 0.3 15.7 35 0.009 0.0806 473.34 5.39E-04 0.08063 46.56 120 0.3 17.9 30 0.010 0.1176 463.68 4.68E-04 0.11758 40.41 1440 0.3 16.3 30 0.010 0.1293 421.53 2.99E-04 0.12934 25.85 360 0.3 14.3 34 0.009 0.1556 420.40 3.61E-04 0.15562 31.21 60 0.3 16.1 30 0.010 0.2352 417.32 4.87E-04 0.23516 42.05

119

...Continued laterally Sat. Error = Calculated - thickness b Hydraulic Cond. % Effect of partial Observed (m) K (m/day) Log (K) penetration T (m2/s) K (m/s) Log (T) Log (k) -1.11E-06 19 11.32 1.0539 96.69 2.48E-03 1.31E-04 -2.61 -3.88 -3.67E-07 24 6.25 0.7958 96.69 1.72E-03 7.23E-05 -2.76 -4.14 -4.31E-07 16 6.40 0.8062 96.69 1.17E-03 7.41E-05 -2.93 -4.13 -9.31E-07 20 5.72 0.7573 96.14 1.31E-03 6.62E-05 -2.88 -4.18 -1.69E-06 26 4.32 0.6357 96.69 1.28E-03 5.00E-05 -2.89 -4.30 -1.13E-06 15 6.65 0.8231 96.69 1.15E-03 7.70E-05 -2.94 -4.11 -4.01E-07 36 2.05 0.3114 96.69 8.60E-04 2.37E-05 -3.07 -4.63 -1.31E-06 14 4.93 0.6925 96.14 7.99E-04 5.70E-05 -3.10 -4.24 -8.49E-07 11 7.82 0.8932 96.14 1.02E-03 9.05E-05 -2.99 -4.04 -1.70E-06 8 10.27 1.0116 95.43 9.78E-04 1.19E-04 -3.01 -3.92 -5.31E-07 19 3.63 0.5599 96.16 8.07E-04 4.20E-05 -3.09 -4.38 -1.68E-06 20 2.15 0.3332 95.37 5.09E-04 2.49E-05 -3.29 -4.60 -1.61E-06 9 5.11 0.7080 95.23 5.40E-04 5.91E-05 -3.27 -4.23

-5.72E-07 30 2.18 0.3377 96.69 7.60E-04 2.52E-05 -3.12 -4.60 -4.56E-06 27 2.37 0.3749 96.69 7.44E-04 2.74E-05 -3.13 -4.56 -7.94E-07 20 3.14 0.4974 96.69 7.21E-04 3.64E-05 -3.14 -4.44 -2.95E-07 8 7.65 0.8837 94.26 6.75E-04 8.85E-05 -3.17 -4.05 -4.51E-07 15 3.80 0.5795 96.14 6.70E-04 4.39E-05 -3.17 -4.36 -1.68E-06 14 4.00 0.6023 96.14 6.35E-04 4.63E-05 -3.20 -4.33 -2.78E-06 19 1.57 0.1949 96.69 3.43E-04 1.81E-05 -3.47 -4.74 -5.30E-07 18 2.52 0.4013 96.71 5.33E-04 2.92E-05 -3.27 -4.54 -1.13E-06 21 2.25 0.3514 96.69 5.39E-04 2.60E-05 -3.27 -4.59 -9.36E-08 8 5.10 0.7075 96.14 4.68E-04 5.90E-05 -3.33 -4.23 -1.24E-06 23 1.15 0.0592 96.14 2.99E-04 1.33E-05 -3.52 -4.88 -1.37E-06 25 1.26 0.1018 96.60 3.61E-04 1.46E-05 -3.44 -4.83 -4.59E-06 27 1.55 0.1903 96.14 4.87E-04 1.79E-05 -3.31 -4.75

120

Well_log T_depth Q Observed Draw ID X Y Elev_m (m) (m3/sec) Q (m3/day) SWL (m) down, so (m) time (hr) 631058 697363.7 203746.2 334.6 34 9.47E-04 81.78 18.3 6.10 1 382029 699269.0 205280.8 331.2 29 1.26E-03 109.04 12.2 9.14 1 402389 699851.4 205254.7 328.0 29 1.26E-03 109.04 12.2 9.14 1 341648 697549.8 203253.5 322.2 28 9.47E-04 81.78 15.8 6.10 1 646372 697215.1 204372.4 342.7 49 1.89E-03 163.56 32.0 16.76 1.5 538221 696521.8 203599.6 327.3 38 9.47E-04 81.78 11.3 8.53 2 823097 699941.9 204816.6 328.6 43 3.16E-03 272.60 13.1 27.43 1 759911 696887.4 204442.8 345.6 43 1.58E-03 136.30 27.7 14.94 2.25 620498 698817.1 205116.7 345.6 44 1.26E-03 109.04 27.4 9.14 1 839852 699463.5 204898.4 345.6 37 9.47E-04 81.78 15.2 9.14 1 822776 699498.8 204880.9 345.6 44 3.16E-03 272.60 12.2 32.00 1 646745 697208.1 203747.0 345.6 45 9.47E-04 81.78 18.3 9.14 1 822785 699607.3 204852.5 345.6 40 2.21E-03 190.82 12.8 25.30 2

517443 696927.6 205699.9 345.6 37 1.26E-03 109.04 19.8 6.10 1 673138 697464.0 203659.1 345.6 32 1.58E-03 136.30 12.2 20.12 2 785814 698947.8 205694.6 345.6 37 1.89E-03 163.56 24.4 12.50 1 840659 698662.3 205039.2 345.6 51 1.89E-03 163.56 28.3 22.86 2 402364 696364.3 204366.2 345.6 41 1.14E-03 98.14 17.7 15.24 1 822821 699872.3 204773.0 345.6 38 1.58E-03 136.30 13.1 24.99 2 694983 697520.5 204109.3 345.6 18 3.16E-04 27.26 9.1 6.10 1 434085 698959.0 204910.8 345.6 43 4.42E-04 38.16 25.0 7.92 10 666439 698538.8 203372.3 345.6 28 1.07E-03 92.68 10.7 15.24 1 517444 696779.0 205510.9 345.6 39 1.26E-03 109.04 21.3 10.67 1 684736 696318.1 204404.6 345.6 47 1.26E-03 109.04 18.9 24.38 24

121

...Continued laterally

L, screen Aquifer Corrected Calc. Calculated Calc. Time length thicknessb drawdown Transmissivity Drawdown Transmissivity 2 2 (sec.) (m) Sp. Cap Sc (=Q/so) (m) L/b for pp. scorr Q/scorr (m /sec.) (m) T (m /day) 60 0.3 13.4 35 0.009 0.2016 405.72 4.76E-04 0.20156 41.10 60 0.3 11.9 35 0.009 0.3024 360.64 4.33E-04 0.30235 37.38 60 0.3 11.9 35 0.009 0.3024 360.64 4.33E-04 0.30235 37.38 60 0.3 13.4 30 0.010 0.2352 347.76 4.20E-04 0.23516 36.31 90 0.3 9.8 35 0.009 0.5543 295.07 3.40E-04 0.55430 29.39 120 0.3 9.6 35 0.009 0.2822 289.80 3.18E-04 0.28219 27.45 60 0.3 9.9 33 0.009 0.9620 283.36 3.57E-04 0.96201 30.83 135 0.3 9.1 35 0.009 0.4938 276.00 2.99E-04 0.49384 25.81 60 0.3 11.9 27 0.011 0.3992 273.16 3.47E-04 0.39916 29.95 60 0.3 8.9 35 0.009 0.3026 270.22 3.44E-04 0.30263 29.69 60 0.3 8.5 34 0.009 1.0793 252.57 3.26E-04 1.07930 28.15

60 0.3 8.9 30 0.010 0.3527 231.84 3.04E-04 0.35274 26.31 120 0.3 7.5 33 0.009 0.8872 215.08 2.49E-04 0.88718 21.54 60 0.3 17.9 13 0.022 0.5263 207.18 2.79E-04 0.52629 24.08 120 0.3 6.8 30 0.010 0.7760 175.64 2.12E-04 0.77602 18.30 60 0.3 13.1 15 0.020 0.9405 173.90 2.43E-04 0.94053 21.00 120 0.3 7.2 28 0.011 0.9448 173.11 2.09E-04 0.94482 18.09 60 0.3 6.4 30 0.010 0.5879 166.93 2.35E-04 0.58789 20.35 120 0.3 5.5 33 0.009 0.8765 155.50 1.92E-04 0.87651 16.60 60 0.3 4.5 35 0.009 0.2016 135.24 2.00E-04 0.20156 17.30 600 0.3 4.8 30 0.010 0.3057 124.84 1.20E-04 0.30570 10.35 60 0.3 6.1 24 0.013 0.7444 124.50 1.88E-04 0.74441 16.24 60 0.3 10.2 13 0.022 0.9240 118.01 1.80E-04 0.92399 15.59 1440 0.3 4.5 30 0.010 0.9406 115.92 9.82E-05 0.94062 8.48

122

...Continued laterally Error = Calculated - Sat. thickness Hydraulic Cond. % Effect of partial Observed b (m) K (m/day) Log (K) penetration T (m2/s) K (m/s) Log (T) Log (k) -3.98E-06 16 2.64 0.4223 96.69 4.76E-04 3.06E-05 -3.32 -4.51 -4.25E-06 17 2.19 0.3405 96.69 4.33E-04 2.53E-05 -3.36 -4.60 -4.25E-06 17 2.19 0.3405 96.69 4.33E-04 2.53E-05 -3.36 -4.60 -2.20E-06 12 2.98 0.4739 96.14 4.20E-04 3.45E-05 -3.38 -4.46 -9.79E-06 17 1.75 0.2439 96.69 3.40E-04 2.03E-05 -3.47 -4.69 -2.02E-06 27 1.02 0.0100 96.69 3.18E-04 1.18E-05 -3.50 -4.93 -1.73E-05 30 1.02 0.0094 96.49 3.57E-04 1.18E-05 -3.45 -4.93 -1.33E-06 15 1.73 0.2376 96.69 2.99E-04 2.00E-05 -3.52 -4.70 -9.15E-06 16 1.85 0.2681 95.63 3.47E-04 2.15E-05 -3.46 -4.67 -7.40E-06 21 1.39 0.1435 96.69 3.44E-04 1.61E-05 -3.46 -4.79 -9.02E-06 32 0.88 -0.0558 96.63 3.26E-04 1.02E-05 -3.49 -4.99 -4.29E-06 27 0.98 -0.0084 96.14 3.04E-04 1.14E-05 -3.52 -4.94

-1.66E-05 27 0.79 -0.1001 96.49 2.49E-04 9.19E-06 -3.60 -5.04 -9.08E-06 17 1.44 0.1573 91.37 2.79E-04 1.66E-05 -3.55 -4.78 -8.39E-06 20 0.91 -0.0411 96.14 2.12E-04 1.05E-05 -3.67 -4.98 -2.04E-05 12 1.68 0.2255 92.47 2.43E-04 1.95E-05 -3.61 -4.71 -8.17E-06 23 0.79 -0.1016 95.87 2.09E-04 9.16E-06 -3.68 -5.04 -1.24E-05 23 0.87 -0.0620 96.14 2.35E-04 1.00E-05 -3.63 -5.00 -5.92E-06 25 0.66 -0.1776 96.49 1.92E-04 7.69E-06 -3.72 -5.11 -3.36E-06 9 1.96 0.2915 96.69 2.00E-04 2.26E-05 -3.70 -4.64 -5.93E-06 18 0.59 -0.2325 96.14 1.20E-04 6.78E-06 -3.92 -5.17 -1.33E-05 17 0.93 -0.0294 95.12 1.88E-04 1.08E-05 -3.73 -4.97 -1.08E-05 18 0.88 -0.0547 91.34 1.80E-04 1.02E-05 -3.74 -4.99 -1.57E-05 28 0.30 -0.5193 96.14 9.82E-05 3.50E-06 -4.01 -5.46

123

Well_log T_depth Q Observed Draw ID X Y Elev_m (m) (m3/sec) Q (m3/day) SWL (m) down, so (m) time (hr) 875179 698281.4 205041.2 345.6 45 2.21E-03 190.82 22.6 6.71 1.5 721009 699094.3 205894.3 345.6 53 1.26E-03 109.04 27.4 25.60 1 646355 696911.8 203631.1 345.6 34 9.47E-04 81.78 11.1 23.17 8 678955 696403.3 204195.7 345.6 42 1.26E-03 109.04 10.7 32.00 2 802118 696896.4 202503.9 345.6 15 6.31E-04 54.52 9.1 5.49 1 221661 697462.0 204074.6 345.6 37 3.16E-04 27.26 22.9 9.75 5 786712 699688.7 206064.4 345.6 55 1.26E-03 109.04 21.9 32.61 1.5 786714 699693.0 206019.1 345.6 38 9.47E-04 81.78 16.2 22.25 2 778843 699637.9 206204.9 345.6 45 9.47E-04 81.78 21.6 23.17 6 853172 696844.8 202892.4 345.6 24 9.47E-04 81.78 1.5 22.25 7.5 423766 696736.5 203952.1 345.6 26 6.31E-04 54.52 12.8 22.86 1 483501 697141.0 205323.0 345.6 38 6.31E-04 54.52 17.7 12.19 10 861025 699093.5 205955.0 345.6 52 1.58E-03 136.30 27.4 24.38 2

698101 697056.8 203780.9 345.6 30 2.52E-04 21.81 18.3 12.19 1 420641 699683.3 205217.1 345.6 39 3.16E-04 27.26 8.5 21.34 1 622904 697180.1 205560.3 345.6 25 4.42E-04 38.16 7.9 24.08 24 680470 696922.1 204131.7 345.6 37 1.26E-04 10.90 18.3 18.90 2 523192 697972.9 205107.1 345.6 63 1.26E-04 10.90 35.1 13.11 0.5

124

...Continued laterally

L, screen Aquifer Corrected Calc. Calculated Calc. Time length thicknessb drawdown Transmissivity Drawdown Transmissivity 2 2 (sec.) (m) Sp. Cap Sc (=Q/so) (m) L/b for pp. scorr Q/scorr (m /sec.) (m) T (m /day) 90 3.0 28.5 22 0.134 1.6957 112.53 1.58E-04 1.69569 13.68 60 0.3 4.3 30 0.010 0.9877 110.40 1.71E-04 0.98765 14.82 480 0.3 3.5 35 0.009 0.7660 106.77 1.09E-04 0.76596 9.44 120 0.3 3.4 30 0.010 1.2346 88.32 1.23E-04 1.23456 10.63 60 0.3 9.9 10 0.030 0.6347 85.90 1.42E-04 0.63468 12.27 300 0.3 2.8 35 0.009 0.3225 84.52 9.83E-05 0.32250 8.50 90 0.3 3.3 29 0.010 1.3015 83.78 1.26E-04 1.30146 10.90 120 0.3 3.7 25 0.012 1.0300 79.40 1.13E-04 1.02996 9.79 360 0.3 3.5 25 0.012 1.0723 76.27 8.74E-05 1.07229 7.55 450 0.3 3.7 24 0.013 1.0729 76.22 8.38E-05 1.07287 7.24 60 0.3 2.4 35 0.009 0.7559 72.13 1.25E-04 0.75586 10.77

600 0.3 4.5 18 0.017 0.7762 70.24 7.44E-05 0.77621 6.43 120 1.0 5.6 27 0.037 2.3017 59.22 9.04E-05 2.30164 7.81 60 0.3 1.8 35 0.009 0.4031 54.10 1.01E-04 0.40313 8.73 60 0.3 1.3 35 0.009 0.7055 38.64 7.95E-05 0.70547 6.87 1440 0.3 1.6 13 0.023 2.1431 17.81 2.07E-05 2.14311 1.79 120 0.3 0.6 35 0.009 0.6249 17.45 3.70E-05 0.62486 3.20 30 0.3 0.8 14 0.022 1.0883 10.02 4.45E-05 1.08833 3.84

125

...Continued laterally

Error = Calculated Sat. thickness Hydraulic Cond. K % Effect of partial - Observed b (m) (m/day) Log (K) penetration T (m2/s) K (m/s) Log (T) Log (k) 1.38E-05 23 0.60 -0.2229 74.71 1.58E-04 6.93E-06 -3.80 -5.16 -1.93E-05 26 0.58 -0.2376 96.14 1.71E-04 6.70E-06 -3.77 -5.17 -1.32E-06 23 0.41 -0.3871 96.69 1.09E-04 4.75E-06 -3.96 -5.32 -2.67E-05 32 0.34 -0.4745 96.14 1.23E-04 3.88E-06 -3.91 -5.41 -1.84E-05 5 2.24 0.3494 88.43 1.42E-04 2.59E-05 -3.85 -4.59 -6.21E-06 14 0.62 -0.2081 96.69 9.83E-05 7.17E-06 -4.01 -5.14 -2.06E-05 33 0.33 -0.4759 96.01 1.26E-04 3.87E-06 -3.90 -5.41 -1.98E-05 22 0.44 -0.3567 95.37 1.13E-04 5.09E-06 -3.95 -5.29 -1.72E-05 23 0.33 -0.4869 95.37 8.74E-05 3.77E-06 -4.06 -5.42 -1.56E-05 22 0.33 -0.4877 95.18 8.38E-05 3.76E-06 -4.08 -5.42 -1.89E-05 13 0.84 -0.0750 96.69 1.25E-04 9.74E-06 -3.90 -5.01 -3.05E-06 20 0.31 -0.5022 93.63 7.44E-05 3.64E-06 -4.13 -5.44

-2.60E-05 24 0.32 -0.4942 90.56 9.04E-05 3.71E-06 -4.04 -5.43 -9.69E-06 12 0.72 -0.1451 96.69 1.01E-04 8.29E-06 -4.00 -5.08 -1.51E-05 30 0.23 -0.6473 96.69 7.95E-05 2.61E-06 -4.10 -5.58 -4.06E-05 17 0.10 -0.9803 91.10 2.07E-05 1.21E-06 -4.68 -5.92 -3.29E-06 19 0.17 -0.7786 96.69 3.70E-05 1.93E-06 -4.43 -5.72 -7.47E-06 28 0.14 -0.8632 91.70 4.45E-05 1.59E-06 -4.35 -5.80

N.B. Radius of the wells = 0.1m Storativity = 0.1 Screen length = 0.3m was assumed.

126

V. Observed (field measured) Vs model computed head data Obs. Obs. Head Confidence STD Computed Residual ID X (m) Y (m) Type Layer Head (m) Interval (m) (%) (m) head (m) head (m) 627837 697199.0 207022.0 obs. pt 3 358 1.5 80 1.17 355.4 -2.63 673138 697463.0 203659.0 " 2 315 1.5 80 1.17 315.1 0.15 621083 697382.0 201943.0 " 5 322 1.5 80 1.17 322.4 0.43 2021357 697060.0 205987.0 " 5 326 1.5 80 1.17 325.1 -0.92 505775 699074.6 202944.2 " 3 345 1.5 80 1.17 344.5 -0.51 666438 697910.0 205599.0 " 5 324 1.5 80 1.17 322.9 -1.14 572017 698231.0 204519.0 " 2 317 1.5 80 1.17 318.4 1.38 875179 698280.0 205040.0 " 2 320 1.5 80 1.17 319.6 -0.38 769181 698657.0 206707.0 " 5 328 1.5 80 1.17 326.2 -1.76 592729 697076.0 206680.0 " 5 329 1.5 80 1.17 327.6 -1.42 685746 696514.0 205333.0 " 5 322 1.5 80 1.17 321.1 -0.87

678978_ 698941.4 202677.7 " 3 349 1.5 80 1.17 347.6 -1.45 431052 698212.0 203575.0 " 5 317 1.5 80 1.17 317.3 0.34 840717 697394.0 205040.0 " 5 318 1.5 80 1.17 317.6 -0.42 690994 697708.0 204112.0 " 2 316 1.5 80 1.17 316.4 0.37 630103 699013.0 205639.0 " 5 324 1.5 80 1.17 323.7 -0.35 525759 697497.4 205693.5 " 2 344 1.5 80 1.17 343.0 -1.02 978283 698864.6 206626.4 " 3 349 1.5 80 1.17 348.0 -1.03 River1 697262.2 203300.8 " 1 313 1.5 95 0.77 313.4 0.44 River2 697949.5 203802.9 " 1 314 1.5 95 0.77 315.6 1.63 River3 698684.2 204060.7 " 1 316 1.5 95 0.77 317.7 1.73 River4 699740.8 204148.6 " 1 320 1.5 95 0.77 320.1 0.10 431129 699640.8 203255.0 " 3 335 1.5 80 1.17 335.2 0.20

127

128

VI. Mass balance of each major aquifer layers

Pottsville Outwash Formation Berea Sandstone

IN OUT IN OUT IN OUT (m3/d) (m3/d) (m3/d) (m3/d) (m3/d) (m3/d) Sources/Sinks Flux across boundary 842 -6126 - - - - Recharge 807 0 1348 - - - Total Source/Sink 1649 -6126 1348 - - - Zone Flow Top 3720 -2192 960 -469 1189 -1191 Bottom 3972 -1882 1 -1082 0 0 Left 231 -1504 25 -274 0 -1 Right 1337 -4 16 -85 1 0 Front 487 -247 30 -375 0 0 Back 579 -284 11 -264 0 0 Total Zone Flow 10327 -6114 1043 -2549 1190 -1192 TOTAL FLOW 11976 -12240 2391 -2549 1190 -1192

% Summary In - Out difference Sources/Sinks -4477 -271 1348 - 0 0 Cell To Cell 4213 41 -1506 -144 -2 -0.2 Total -264 -2 -158 -7 -2 -0.2

128

VII. Estimation of rate of flow contribution from bedrock aquifers along sections across the buried valley.

Pottsville Formation

Column Rate of flow No. Rate of flow from each cells along the section per cell (50m) - - - 67 0.10 0.23 -3.25 -1.60 -0.22 1.76 -7.15 - - - 62 0.26 0.56 -0.11 -2.20 -1.95 1.98 -1.32 -7.78 -16.17 ------57 0.29 0.25 -0.16 -0.22 -2.06 2.43 -1.97 13.69 6.20 0.29 -27.56 - - - 52 1.57 0.37 -3.88 -5.70 -1.06 0.66 -2.36 -4.58 -20.16 - - - 47 4.07 0.54 -6.78 -0.73 -0.18 1.66 -0.15 -14.11 - - - - 42 3.59 0.06 23.59 -1.33 -2.57 2.45 -33.58 - - - 37 2.10 3.00 -0.16 -0.02 -1.90 0.87 -6.15 -9.52 -23.72 ------32 7.65 0.76 -6.71 -1.57 -4.23 0.29 23.76 -3.06 3.20 1.08 -52.30 - - - - - 27 3.10 2.18 -0.11 42.68 15.81 1.83 -65.71 - - - - 22 0.67 2.32 -3.09 -1.71 -1.52 1.15 -6.69 -3.59 1.38 -22.12 ------17 0.65 0.29 -4.51 -1.44 -1.36 0.62 -1.97 -0.63 0.55 1.55 1.47 0.57 -15.61 Average (m3/day) -27 N.B. Negative sign indicates an outflow whereas inflow is positive. Total outflow (m3/d) per km length 542 Total outflow (m3/year) per km length 198,023 Mm3/yr 0.20

129

Berea sandstone

Column Rate of flow No. Rate of flow from each cells along the section per cell (50m) ------68 0.46 -0.72 -0.76 -0.45 -0.05 0.19 -0.36 -0.33 0.31 0.25 0.25 0.21 0.10 0.02 0.09 0.30 0.61 -3.47 ------63 1.95 -1.28 -0.21 -0.01 -0.02 0.11 -0.14 -0.14 0.17 0.19 0.20 0.15 0.09 0.07 0.08 0.23 0.45 0.77 -3.20 ------58 2.62 -1.59 -0.71 -0.32 -0.27 0.18 -0.05 -0.02 0.13 0.23 0.24 0.22 0.24 0.18 0.10 0.03 0.02 0.09 0.08 -6.94 ------53 0.39 -2.76 -1.49 -0.73 -0.24 0.01 -0.02 -0.21 0.37 0.49 0.56 0.67 0.69 0.74 0.90 0.98 -11.24 ------48 0.59 -3.16 -1.93 -1.14 -0.61 0.29 -0.02 -0.01 0.05 0.39 0.42 0.55 0.71 0.96 1.32 1.80 0.23 -14.16 ------43 1.70 -2.94 -1.83 -1.14 -0.78 0.55 -0.19 -0.01 0.14 0.32 0.43 0.61 0.89 1.36 2.12 0.56 -15.60 ------38 5.01 -3.04 -1.81 -1.13 -0.67 0.49 -0.10 -0.11 0.21 0.37 0.57 0.99 1.68 2.90 1.94 -21.02 ------33 0.36 -4.94 -2.93 -1.70 -1.02 0.63 -0.05 -0.01 0.23 0.28 0.52 0.79 1.34 2.13 3.51 -20.44 ------28 3.99 -4.86 -2.90 -1.71 -0.93 0.04 -0.02 -0.30 0.35 0.53 0.82 1.34 2.16 3.47 0.29 -23.71 ------23 7.19 -4.26 -2.41 -1.02 -0.13 0.01 -0.01 -0.25 0.42 0.49 0.71 1.05 2.60 4.17 1.03 -25.75 ------18 7.22 -4.03 -1.98 -0.62 -0.04 0.07 0.14 0.25 0.01 0.23 0.25 0.41 0.63 1.13 1.92 3.28 5.52 0.77 -27.58 ------13 1.84 13.13 -7.41 -4.00 -1.96 0.83 -0.28 -0.14 0.13 0.06 0.05 0.01 0.01 0.26 0.61 1.14 2.00 3.41 5.82 9.87 -52.83 Average (m3/day) -18.83 N.B. Negative sign indicates an outflow whereas inflow is positive. Total outflow (m3/d) per km length 376.56 Total outflow (Mm3/year) per km length 137536.93 in Mm3/yr 0.14 The contribution ratio of Berea Sandstone to Pottsville Formation is approximately 2:3.

130