Prepared in cooperation with the National Park Service

Hydrologic Data and Groundwater-Flow Simulations in the 

Brown Ditch Watershed, Indiana Dunes National Lakeshore, 

Near Beverly Shores and Town of Pines, Indiana

Scientific Investigations Report 2015–5141

U.S. Department of the Interior

U.S. Geological Survey

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2015–5141

Hydrologic Data and Groundwater-Flow Simulations in the 

Brown Ditch Watershed, Indiana Dunes National Lakeshore, 

Near Beverly Shores and Town of Pines, Indiana
USGS Stream Gage Brown Ditch at Beverly Shores, IN (USGS 04095154), 

taken on June 11, 2013, by David C. Lampe.
Hydrologic Data and Groundwater-Flow 

Simulations in the Brown Ditch Watershed, 

Indiana Dunes National Lakeshore, 

Near Beverly Shores and Town of Pines, 

Indiana

By David C. Lampe

Prepared in cooperation with the National Park Service

Scientific Investigations Report 2015–5141

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Director

U.S. Geological Survey, Reston, Virginia: 2016

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as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Lampe, D.C., 2015, Hydrologic data and groundwater-flow simulations in the Brown Ditch Watershed, Indiana Dunes 

National Lakeshore, near Beverly Shores and Town of Pines, Indiana: U.S. Geological Survey Scientific Investigations 

Report 2015– 5141, 97 p., http://dx.doi.org/10.3133/sir20155141.

ISSN 2328-0328 (online)
iii

Acknowledgments

The authors gratefully recognize the contributions of many persons to this study. 

Several National Park Service (NPS) personnel from the Indiana Dunes National Lakeshore 

made meaningful contributions: Daniel Mason provided valuable logistical support, background 

information, and technical contributions; Robert Daum and Gia Wagner made administrative and 

technical contributions; Adam Walker, Steve Smith, Robert Langele, and Vaso Stojic assisted 

with well installation, clearing debris, and data collection; and Krystle Dove assisted with 

digitizing historic water-level data. Elizabeth Perry of AECOM and Valerie Blumenfeld of Brown 

Transportation arranged access and permitted data collection at a network of wells within Town 

of Pines. Kevin Breitzke of the Porter County Surveyor’s office assisted with permissions to 

access digital elevation data. Jesse Wright, a student at Indiana University-Purdue University 

Indianapolis assisted with reconstruction of a legacy groundwater simulation from the study 

area. 

The following current and former USGS personnel also assisted with this project: Lee Watson 

(retired; well installation and data collection); David Cohen and Leslie Arihood (retired; technical 

assistance); Amanda Egler (data collection); Douglas Zettwoch and Gary Martin (streamgage 

installation); Edward Dobrowolski, Zachary Martin, Eric Looper, Howard Mills, Andrew Gorman, 

Bradley Reinking, and Larry Myers (streamgage maintenance and discharge measurements); 

Travis Cole (data collection and quality assurance); and Becky Travis (digitizing historic waterlevel data). The author would like to thank the following USGS personnel for their review of this 

report: Jason Pope (technical review; USGS Virginia Water Science Center), Patrick Mills 

(technical review; USGS Illinois Water Science Center), Randall Bayless (specialist review; 

USGS Indiana Water Science Center), and Bonnie J. Stich (editorial review; USGS SPN, 

Columbus Publishing Service Center).

v

Contents

Acknowledgments........................................................................................................................................iii

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................2

Purpose and Scope ..............................................................................................................................4

Description of Study Area ...................................................................................................................4

Groundwater and Surface-Water Resources...........................................................................................8

Hydrogeologic Setting .........................................................................................................................8

Methods of Investigation.....................................................................................................................8

Groundwater Levels and Flow in the Surficial Aquifer.................................................................20

Recharge.....................................................................................................................................24

August–November 1982 Levels and Flow..............................................................................24

March 2013 Levels and Flow....................................................................................................24

April 2014 Levels and Flow .......................................................................................................35

Groundwater/Surface-Water Interaction..............................................................................37

Surface-Water Flow...........................................................................................................................37

Hydrologic Modeling Parameters From Previous Studies...........................................................40

Simulation of Groundwater Flow ..............................................................................................................42

Simplifying Assumptions of the Conceptual Model ......................................................................42

Reconstruction of the Original Groundwater-Flow Model...........................................................43

Results of the Reconstructed Model .....................................................................................43

Modification of the Original Groundwater-Flow Model to Incorporate 

Current Conditions ................................................................................................................43

Spatial Discretization .........................................................................................................................45

Boundary Conditions.................................................................................................................45

Hydraulic Properties .................................................................................................................49

Recharge.....................................................................................................................................49

Model Calibration................................................................................................................................49

Model Parameters.....................................................................................................................52

Observations and Observation Weights ................................................................................52

Simulation Results ..............................................................................................................................52

Calibrated Parameter Values...................................................................................................55

Model Fit to Observations ........................................................................................................55

Simulated Water Budget ..........................................................................................................58

Simulated Water Levels and Groundwater-Flow Paths ......................................................62

Simulated Inundated Areas .....................................................................................................66

Sensitivity Analysis....................................................................................................................66

Model Simulations of Hydrologic Modifications and Climatic Effects on the 

Brown Ditch Watershed.......................................................................................................68

Simulated Inclusion of Beaver Dam to Brown Ditch at Central Avenue..........................68

Adjustment of Parameter Values to Hydrologic Conditions ......................................69

Observations......................................................................................................................70

Model Fit to Observations ...............................................................................................70

Simulated Water Budget .................................................................................................73
vi

Simulated Water Levels and Groundwater-Flow Paths .............................................74

Simulated Inundated Areas ............................................................................................76

Simulated Inclusion of Pool-Riffle Control Structures in Brown Ditch.............................76

Simulated Increase in Level of Lake Michigan.....................................................................83

Simulated Decrease in Level of Lake Michigan ...................................................................83

Model Limitations and Qualifications..............................................................................................88

Comparison of Results to Previous Investigations........................................................................88

Summary and Conclusions.........................................................................................................................89

References Cited..........................................................................................................................................91

Appendix 1.....................................................................................................................................................93

Figures

1. Map showing the location of study area, Lake Michigan Basin, and weather 

stations near the Indiana Dunes National Lakeshore, northwestern Indiana ...................2

2. Map showing the location of study area and surrounding hydrologic and cultural 

features near the Indiana Dunes National Lakeshore, northwestern Indiana...................3

3. Conceptual diagrams showing interactions of precipitation with recharge 

and groundwater levels in a hypothetical unconfined sand aquifer ...................................6

4. Diagrams of generalized groundwater flow. A, Under natural conditions.

B, Affected by tile drain flow. C, Affected by surface-water-level change in 

adjacent discharge ditch.............................................................................................................7

5. Map showing the location of study area, hydrologic cross sections, former 

monitoring wells, and surface-water features in the Great Marsh study area, 

Indiana Dunes National Lakeshore, near Beverly Shores, Indiana.....................................9

6. Hydrogeologic section A–A’ showing the surficial aquifer, confining unit, basal 

sand aquifer, underlying shale and carbonate bedrock, and local and regional 

directions of groundwater flow................................................................................................10

7. Map showing the unconsolidated aquifer systems in the Lake Michigan region 

and the study area, northwestern Indiana .............................................................................11

8. Map showing the location of study area and groundwater-data-collection 

sites in the Great Marsh study area, Indiana Dunes National Lakeshore, 

near Beverly Shores, Indiana ...................................................................................................16

9. Map showing the location of study area and surface-water data-collection 

sites in the Great Marsh area, Indiana Dunes National Lakeshore, near Beverly 

Shores, Indiana ...........................................................................................................................18

10. Photographs showing typical surface-water measurement sites. A, Stable 

culvert end at site BD-CENT. B, Staff gage at site SG1........................................................20

11. Box-and-whisker plots of monthly precipitation statistics for the combined 

records from the weather stations at Ogden Dunes (1951–89) and Indiana Dunes 

National Lakeshore, northwestern Indiana (1989–2013), and precipitation from 

April 2012–December 2013........................................................................................................25

12. Graphs showing temperature, precipitation, and snow depth from records from 

the weather station at Indiana Dunes National Lakeshore, northwestern Indiana, 

May 2012–December 2013 ........................................................................................................26
vii

13. Map showing the altitude of the water table in the surficial aquifer measured 

on August 5, 1982, during dry-weather conditions, in the vicinity of Great Marsh, 

Indiana Dunes National Lakeshore, near Beverly Shores, Indiana...................................27

14. Hydrogeologic section and water-table altitude in November 1982 and 

March 2013 in the surficial aquifer along Carolina Avenue, Indiana Dunes 

National Lakeshore, near Beverly Shores, Indiana ..............................................................28

15. Map showing the altitude of the water table in the surficial aquifer measured 

on March 27–28, 2013, during wet-weather conditions, in the vicinity of Great 

Marsh, Indiana Dunes National Lakeshore, near Beverly Shores, Indiana .....................29

16. Hydrographs of continuous water-level altitude in 11 wells and discrete 

water-levels at 6 sites, May 2012–December 2013, near Great Marsh, 

Indiana Dunes National Lakeshore, Indiana. A, East-west transect of five 

wells and one surface-water monitoring site. B, North-south transect of six 

wells just east of Lakeshore County Road. C, North-south transect of six wells 

and one surface-water monitoring site. D, Subset of the sites shown on figure 

16B of three wells and one surface-water monitoring site detailing gradient 

reversals. E, Subset of the sites shown on figure 16C of three wells detailing 

gradient reversals.......................................................................................................................30

17. Photographs showing A, a beaver dam located at U.S. Geological Survey (USGS) 

streamgage 04095154 in Brown Ditch on the upstream side of Central Avenue, 

and B, a beaver dam in relation to the staff gage located at USGS streamgage 

04095154 .......................................................................................................................................35

18. Map showing the altitude of the water table in the surficial aquifer measured 

on April 29, 2014,during wet-weather conditions in the vicinity of Great Marsh, 

Indiana Dunes National Lakeshore, near Beverly Shores, Indiana...................................36

19. Graphs showing the daily value discharge data for May 2012–December 2013 

from two streamgages. A, U.S. Geological Survey (USGS) 04095100, 

Derby Ditch at Beverly Shores, Indiana. B, USGS 04095158, Kintzele Ditch 

at Beverly Shores, Indiana........................................................................................................39

20. Map showing the comparison of the results of the dredging experiment using 

the original model published by Shedlock and Harkness (1984) to the results of 

a similar experiment using the reconstructed MODFLOW-NWT model ...........................44

21. Map showing the model grid used in the simulation of groundwater flow in 

the vicinity of Great Marsh, near Beverly Shores, Indiana .................................................46

22. Cross section showing the layering design for the model in the vicinity 

of Great Marsh, near Beverly Shores, Indiana......................................................................47

23. Map showing the boundary conditions and drain cells used in the simulation 

of groundwater flow in the study area....................................................................................48

24. Map showing the hydraulic conductivity distribution within model area of 

layers 2 and 3...............................................................................................................................50

25. Map showing the location of recharge zones in the town of Beverly Shores, 

Town of Pines, and other undeveloped and wetland areas of the groundwater-flow 

model; and point representing the discharge of water from the Beverly Shores 

flowing well..................................................................................................................................51

26. Graphical analysis of model fit. A, Simulated and observed water levels. 

B, Weighted simulated and weighted observed water levels. C, Normal probability 

plot of weighted residuals. D, Weighted residuals and simulated water levels..............56

27. Map showing the difference between observed and simulated water levels 

for the modified groundwater-flow model of the Great Marsh area near 

Indiana Dunes National Lakeshore, Indiana..........................................................................58
viii

28. Map showing the zones representing Great Marsh west of Lakeshore 

County Road, Great Marsh east of Lakeshore County Road, the town of Beverly 

Shores, and Town of Pines used in the estimates of individual water budgets and 

groundwater-flow interactions with the modified groundwater-flow model of the 

Great Marsh area near Indiana Dunes National Lakeshore, Indiana................................60

29. Map showing the simulated water-table contours from the modified 

groundwater-flow model of the Great Marsh area near Indiana Dunes 

National Lakeshore, Indiana.....................................................................................................63

30. Map showing the flow lines representing simulated groundwater-flow paths 

in the surficial aquifer under steady-state conditions, March 2013, near 

Indiana Dunes National Lakeshore, Indiana..........................................................................64

31. Cross sections showing vertical flow paths simulated with the modified 

groundwater-flow model. A., Flow paths along column 52 and through Derby 

Ditch. B., Flow paths along column 197 and through Brown Ditch....................................65

32. Map showing the simulated water-table position within areas near the town 

of Beverly Shores, Town of Pines, and within Great Marsh, Indiana Dunes 

National Lakeshore, Indiana, March 2013..............................................................................67

34. Box-and-whisker plots of monthly precipitation statistics for the combined 

records from the weather stations at Ogden Dunes (1951–89) and Indiana Dunes 

National Lakeshore, northwestern Indiana (1989–2013), and precipitation during 

January–May 2014 .....................................................................................................................70

34. Map showing the difference between observed and simulated water levels for 

the April 2014 simulation of the Great Marsh area near Indiana Dunes National 

Lakeshore, Indiana .....................................................................................................................72

35. Map showing the simulated water-table contours from the April 2014 simulation.........75

36. Map showing the flow lines representing simulated groundwater-flow paths in 

the surficial aquifer under the steady-state hydraulic conditions of April 2014 ..............77

37. Map showing the simulated water-table position within areas near the town 

of Beverly Shores, Town of Pines, and within Great Marsh, Indiana Dunes 

National Lakeshore, Indiana, April 2014 .................................................................................78

38. Map showing the approximate location of six simulated control structures and 

their simulated altitude in Brown Ditch, the difference in water-table position 

between the March 2013 simulation results, and a model scenario simulating 

the inclusion of six control structures in Brown Ditch during the March 2013 

hydrologic condition near the town of Beverly Shores, Town of Pines, and within 

Great Marsh, Indiana Dunes National Lakeshore, Indiana.................................................79

39. Map showing the water-table position resulting from a model scenario 

simulating the inclusion of six control structures in Brown Ditch during the 

March 2013 hydrologic condition near the town of Beverly Shores, Town of 

Pines, and within Great Marsh, Indiana Dunes National Lakeshore, Indiana .................80

40. Map showing the increases in water level at groundwater-monitoring wells 

and surface-water monitoring sites in the March 2013 simulation, which 

includes six control structures in Brown Ditch .....................................................................82

41. Map showing approximate location of six simulated control structures and their 

simulated altitude in Brown Ditch, the difference in water-table position between 

the March 2013 simulation results, and a model scenario simulating the inclusion 

of six control structures in Brown Ditch during the March 2013 hydrologic 

condition using MODFLOW River package to simulate Brown Ditch within Great 

Marsh near the town of Beverly Shores, Town of Pines, and within Great Marsh, 

Indiana Dunes National Lakeshore, Indiana..........................................................................84
ix

42. Map showing inundated land surface areas resulting from a model scenario 

simulating the inclusion of six control structures in Brown Ditch during the 

March 2013 hydrologic condition using MODFLOW River package to simulate 

Brown Ditch within Great Marsh near the town of Beverly Shores, Town of Pines, 

and within Great Marsh, Indiana Dunes National Lakeshore, Indiana .............................85

43. Map showing the water-table position resulting from a model scenario 

simulating the water level of Lake Michigan at extreme high level and 

March 2013 conditions near the town of Beverly Shores, Town of Pines, and 

within Great Marsh,Indiana Dunes National Lakeshore, Indiana......................................86

44. Map showing the water-table position resulting from a model scenario 

simulating the water level of Lake Michigan at extreme low level and 

March 2013 conditions near the town of Beverly Shores, Town of Pines, 

and within Great Marsh, Indiana Dunes National Lakeshore, Indiana .............................87

Tables

 1. Lithostratigraphy of the study area in the context of northwestern 

Indiana hydrogeologic units .....................................................................................................12

2. Characteristics of groundwater-monitoring wells in the study area................................13

3. Characteristics of surface-water data-collection sites in the study area........................19

4. Water-level measurements made on August 5, 1982 ...........................................................21

 5. Water-level measurements made on March 27, 2013, and April 29, 2014.........................22

6. Discrete discharge measurements from streams and ditches in the study area ...........38

7. Monthly mean discharge for U.S. Geological Survey station numbers 04095100, 

Derby Ditch at Beverly Shores, Indiana; and 04095158, Kintzele Ditch at Beverly 

Shores, Indiana ...........................................................................................................................40

 8. Hydrologic parameters used or estimated from field measurements in previous 

studies in northwestern Indiana ..............................................................................................41

9. Final parameter values and parameter composite-scaled sensitivities used in the 

modified model simulations ......................................................................................................53

10. Measured (observed) and model-calculated (simulated) water levels and 

discharge measurements used as observations and model residuals for the 

modified groundwater model....................................................................................................54

11. Computed statistics based on the water-level and gain/loss residuals for the 

modified groundwater-flow model...........................................................................................59

12. Water budget associated with the modified groundwater-flow model.............................59

13. Water budgets for four zones of the groundwater-flow model simulating 

Great Marsh west of Lakeshore County Road, Great Marsh east of Lakeshore 

County Road, the town of Beverly Shores, and Town of Pines...........................................61

14. Model parameters with the original values and the adjusted values used to 

match the April 2014 simulation ...............................................................................................69

15. Measured and model-calculated water levels and discharge measurements 

and modeled residuals for the April 2014 simulation............................................................71

16. Computed statistics based on the unweighted water-level residuals for the 

April 2014 hydrologic condition ................................................................................................73

17. Water budget associated with the groundwater-flow model simulating the 

April 2014 hydrologic condition ................................................................................................73
x

18. Water budgets for four zones of the groundwater-flow model simulating 

Great Marsh west of Lakeshore County Road, Great Marsh east of Lakeshore 

County Road, the town of Beverly Shores, and Town of Pines...........................................74

19. Water budgets of four zones of the groundwater-flow model simulating 

Great Marsh west of Lakeshore County Road, Great Marsh east of Lakeshore 

County Road, the town of Beverly Shores, and Town of Pines using the 

simulation that includes six control structures in Brown Ditch..........................................81

Conversion Factors

[Inch/Pound to International System of Units[

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2

)

acre 0.4047 hectare (ha)

acre 0.004047 square kilometer (km2

)

square mile (mi2

) 259.0 hectare (ha)

square mile (mi2

) 2.590 square kilometer (km2) 

Flow rate

foot per day (ft/d) 0.3048 meter per day (m/d)

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

gallon per day (gal/d) 0.003785 cubic meter per day (m3

/d)

million gallons per day (Mgal/d) 0.04381 cubic meter per second (m3

/s)

inch per month (in/month) 25.4 millimeter per month (mm/

month)

inch per year (in/yr) 25.4 millimeter per year (mm/yr)

Mass

pound, avoirdupois (lb) 0.4536 kilogram (kg) 

Pressure

pound per square inch (lb/in2

) 6.895 kilopascal (kPa) 

Hydraulic conductivity

foot per day (ft/d) 0.3048 meter per day (m/d)

Hydraulic gradient

foot per mile (ft/mi) 0.1894 meter per kilometer (m/km)

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as:

°C = (°F – 32) / 1.8.
xi

Datum

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

Selected altitudes include a reference to the National Geodetic Vertical Datum of 1929 (NGVD 

29), as specifically described in the report text.

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Altitude, as used in this report, refers to distance above the vertical datum.

Time is referenced to Eastern Standard Time.

Abbreviations and Acronyms

CSS composite scaled sensitivities

IDNR Indiana Department of Natural Resources

INDU Indiana Dunes National Lakeshore

Kh horizontal hydraulic conductivity

ks surficial sand aquifer

Kv vertical hydraulic conductivity

lidar light detection and ranging

NOAA National Oceanic and Atmospheric Administration

NPS National Park Service

PVC Polyvinyl chloride

RMSE root mean square error

USGS U.S. Geological Survey

Hydrologic Data and Groundwater-Flow Simulations 

in the Brown Ditch Watershed, Indiana Dunes National 

Lakeshore, Near Beverly Shores and Town of Pines, Indiana

By David C. Lampe

Abstract

The U.S. Geological Survey (USGS) collected data and 

simulated groundwater flow to increase understanding of the 

hydrology and the effects of drainage alterations on the water 

table in the vicinity of Great Marsh, near Beverly Shores and 

Town of Pines, Indiana. Prior land-management practices have 

modified drainage and caused changes in the distribution of 

open water, streams and ditches, and groundwater abundance 

and flow paths. 

Collected hydrologic data indicate that the majority of 

water entering Great Marsh flows from the southern dune 

ridge beneath Town of Pines, Indiana. Groundwater flow is 

intercepted by Brown Ditch in the eastern portion of the study 

area and Derby Ditch in the western portion of the study 

area. A smaller amount of groundwater from the northern 

dune ridge beneath Beverly Shores also contributed water to 

Great Marsh. Continuous groundwater-level data collected 

indicate that the predominant north-south groundwater-flow 

gradients vary during the course of the year due to increased 

levels of precipitation or during periods of drainage obstructions. Continuous surface-water discharge and surface-water 

elevation were measured at three USGS streamgages, one each 

on Brown, Kintzele and Derby Ditches. The monthly mean 

discharge statistics indicate that during the period of record—

June 2012 to September 2013—streamflow in Kintzele Ditch 

was lowest during July 2012 and highest during April 2013. 

In Derby Ditch, streamflow also was lowest during July 2012 

and highest during April 2013.

Periods of relatively high and low groundwater levels 

during August 1982, March 2013, and April 2014 were 

examined and simulated by using MODFLOW and companion 

software. Results from the simulation of conditions during 

March 2013 include that nearly 100 percent of all water entering the area simulating Town of Pines is from recharge. Of all 

the water simulated to enter the eastern and western portions 

of Great Marsh, nearly 20 and 18 percent, respectively, flows 

from Town of Pines to the western and eastern portions of 

Great Marsh. The dune ridges beneath Town of Pines and to 

a lesser extent beneath Beverly Shores are a major source of 

recharge to the surficial aquifer and Great Marsh. 

Results from the simulation of the conditions of April 

2014 include that, despite increases in the amount of water 

entering Great Marsh due to a beaver-dam-modified hydrologic condition, there is still virtually zero simulated groundwater flow from Great Marsh to Town of Pines. The volume of 

water simulated to be entering the zone representing Beverly 

Shores decreased by 0.43 cubic foot per second from the 

results of the March 2013 simulation. This simulated difference in water budgets can be attributed to increased simulated 

recharge in Great Marsh and Town of Pines. Effects of the 

inclusion of the beaver dam included the increase of the simulated water table and simulated inundated area upstream of the 

beaver dam due to the effects of ponding surface water. 

Results from the simulation scenario that includes six 

proposed pool-riffle control structures in Brown Ditch under 

the hydrologic conditions of March 2013 indicate areas inundated by water are larger, including areas just to the north of 

the entrance of Brown Ditch into Great Marsh, and areas north 

of the confluence of Brown and Kintzele Ditches.

Results from the scenario simulating the increase of the 

Lake Michigan water level to the historical high of May 31, 1998, 

showed inundated areas of Great Marsh south of Beverly Shores 

enlarged on both sides of Lakeshore County Road with the 

greatest enlargement simulated to be southeast of the intersection of Lakeshore County Road and Beverly Drive. For the 

scenario simulating the decrease of the Lake Michigan water 

level to the historical low of December 23, 2007, results show 

little change from the original March 2013 inundated area.

The results of this study can be used by water-resource 

managers to understand how surrounding ditches affect water 

levels in Great Marsh and other inland wetlands and residential areas. The groundwater model developed can be applied to 

answer questions about how alterations to the drainage system 

in the area affects water levels in the public and residential areas surrounding Great Marsh. The modeling methods 

developed in this study provide a template for other studies of 

groundwater flow and groundwater/surface-water interactions 

within the shallow surficial aquifer in northern Indiana, and in 

similar hydrologic settings that include surficial sand aquifers 

in coastal areas. 
2 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Introduction

The Indiana Dunes National Lakeshore (INDU) was 

formally established in 1973 as part of a continuing effort to 

preserve the dunes and wetlands along the southern shore of 

Lake Michigan in northwestern Indiana (fig. 1). The National 

Park Service (NPS) is charged with preserving and managing 

the aesthetic, scientific, and recreational resources of the INDU. 

Industrial and urban development during the 19th and 20th

centuries has substantially modified the study area. Changes 

to the natural drainage system and other cultural disturbances 

have affected the hydrology of the lake-wetland complex in the 

vicinity of Great Marsh near the town of Beverly Shores and 

Town of Pines (fig. 2). The NPS and other resource managers 

in the area require an improved understanding of the hydrology 

in the vicinity of Great Marsh in order to understand the effects 

of drainage alterations on the water levels of Great Marsh and 

on the water table in the neighboring residential areas.

Kankakee River

Kankakee River

INDIANA

ILLINOIS

MICHIGAN

INDIANA

LAPORTE

LAKE

PORTER

INDIANA

41° 40'

41° 30'

41° 20'

87°30' 87°15' 87° 86°45'

0 5 10 MILES

0 5 10 KILOMETERS

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

North American Datum of 1983

Michigan City

Beverly Shores

Gary

LaPorte

Valparaiso

LAKE MICHIGAN

Chesterton

East

Chicago

Hammond

EXPLANATION

Study area

Indiana Dunes National Lakeshore (NL)—

 Property boundary

City

Station 126542 

OGDEN DUNES, IN

Station 124244 

INDIANA DUNES NL

Station 124244 

INDIANA DUNES NL

Town of Pines

Little Calum et Rive r

Grand Calumet River

Lake Michigan Basin boundary

Precipitation station used for this study

Figure 1. Location of study area, Lake Michigan Basin, and weather stations near the Indiana Dunes National Lakeshore, 

northwestern Indiana.
Introduction 3

Brown Ditch

Derby Ditch

Kintzele

Ditch LAKE MICHIGAN

12

20

INDIANA DUNES

STATE PARK

GREAT MARSH

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

EXPLANATION

Model boundary

North American Datum of 1983

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58’ 86° 57' 86° 56' 86° 55'

Figure 2. Location of study area and surrounding hydrologic and cultural features near the Indiana Dunes National Lakeshore, 

northwestern Indiana.

The U.S. Geological Survey (USGS) provides reliable 

scientific information to describe the interaction of hydrologic 

systems and assists in understanding their effects on natural 

lands and adjacent property. In most instances, these efforts 

involve documenting and analyzing the effects of widely 

recognized phenomena such as surface-water and groundwater 

flow and quality. On occasion, they involve relatively smallscope studies of previously unrecognized phenomena, such as 

the use of groundwater-flow simulations to understand interactions of changes in groundwater drainage with wetland water 

levels and the potential for groundwater flooding. The USGS 

works within its strategic science direction and with its partner 

organizations, such as the NPS, to document these emerging 

hazards and to ensure that scientific methods are applied effectively to better understand these phenomena at INDU and in 

similar hydrologic settings that include surficial sand aquifers 

in coastal settings.

The USGS, in cooperation with the NPS, has been 

studying flow and water quality in the surficial aquifer at 

INDU since 1973. The USGS initially studied the area in 

cooperation with the NPS to determine shallow groundwater 

flow and the effects of drainage modification in reaches of 

Brown Ditch on water levels within the surficial sand aquifer 

in INDU and Town of Pines (Shedlock and Harkness, 1984). 
4 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

That evaluation used a two-dimensional finite-difference 

groundwater-flow model. During 2007–10, the USGS, in 

cooperation with the NPS, investigated the effect of natural 

and human-affected hydrologic processes on changes in 

groundwater and surface-water levels and groundwater-flow 

directions in nearby parts of a dune-beach complex in and 

around Beverly Shores, Indiana (Buszka and others, 2011). 

In May 2012, the USGS initiated an investigation in cooperation with the NPS to evaluate the hydrology in the vicinity of 

Great Marsh that included measurement of surface-water and 

groundwater levels, the measurement of continuous discharge 

from Brown and Kintzele Ditches, and development of a 

steady-state groundwater-flow model similar to that documented by Shedlock and Harkness (1984). An updated understanding of the hydrologic system was needed to (1) manage 

and restore Great Marsh, and (2) understand the effects on the 

hydrologic system and the surrounding residential and natural 

areas that result from drainage modifications and wetland restorations that have been made, are planned, or are hypothetical. This investigation by the USGS and its partners will aid 

in comprehending how natural and human-affected hydrologic 

processes affect shallow groundwater levels in an unconfined 

surficial aquifer surrounding and beneath Great Marsh in the 

INDU in Porter County, Indiana. 

Purpose and Scope

This report describes interpretation of hydrologic data, 

and development and use of a groundwater-flow model in 

simulations to show how natural and human-affected hydrologic processes affect shallow groundwater levels in an unconfined surficial aquifer surrounding and beneath Great Marsh. 

The groundwater-flow model was developed to be available, if 

needed, as a tool to help evaluate future management actions.

Water levels were measured during May 2012–December 

2013 to understand flow directions in the surficial aquifer and 

establish a consistent reference to compare with and quality assure results from the groundwater-flow simulations. 

Continuous water-level and weather data also are presented 

and interpreted to characterize the transient groundwater-flow 

system and identify steady-state water-level periods in the 

surficial aquifer. 

The purpose of the calibrated groundwater model is to 

numerically represent groundwater/surface-water interactions 

in the shallow hydrologic system of the area surrounding Great 

Marsh so that various simulations can be made that represent 

different drainage modifications. The model was calibrated to 

a relatively wet hydrologic condition to examine the specific 

effects on the surrounding land uses. Four different scenarios 

were completed:

• A simulation of the effects of a beaver dam installed 

in the main channel of Brown Ditch upstream of 

Central Avenue on the surrounding water table. Results 

of the simulation are compared to data collected on 

April 29, 2014, while such a beaver dam was present.

• A simulation of the effects of six proposed pool-riffle 

structures and spillways that could be installed in the 

main channel of Brown Ditch downstream of highway 

US-12 to restore wetlands. 

• Simulations of the effects of record high 

Lake Michigan lake levels (stage) on the water 

table within Great Marsh to represent conditions 

typical of recent Lake Michigan level variations. 

• A simulation of the effects of a record low 

Lake Michigan stage on the water table within 

the Great Marsh to represent conditions typical of 

recent Lake Michigan level variations. 

The study evaluates the potential effects of drainage 

modifications and changes to the levels of Lake Michigan on 

the surrounding residential and natural areas by comparing 

simulation results for each scenario to baseline conditions or 

the results of another scenario. Water-table distributions for 

each simulation are compared with the altitudes of hypothetical subgrade structures (basements, roadbeds, or railbeds) in 

the model area. 

Description of Study Area

The study area is in northeastern Porter County in 

northwestern Indiana (fig. 1). The investigation is focused 

principally on an area that includes portions of INDU, the 

town of Beverly Shores, and Town of Pines, and is bounded 

on the west by Indiana Dunes State Park, the north by Lake 

Michigan, the east by Michigan City, Indiana, and the south 

by portions of highway US-20 and Brown Ditch (fig. 2). As of 

the 2010 census, the populations of Beverly Shores and Town 

of Pines were 613 and 708, respectively (U.S. Census Bureau, 

2013). Great Marsh, the largest interdunal wetland near the 

Lake Michigan shore at INDU, crosses through the study area 

(fig. 2). Derby Ditch drains portions of the residential area of 

Beverly Shores and wetlands within the dune-beach complex 

to Lake Michigan. Brown Ditch drains portions of Town of 

Pines residential area and portions of Great Marsh north of 

US-12 and south of Beverly Drive in INDU to Kintzele Ditch. 

Kintzele Ditch drains Brown Ditch, portions of the residential 

area of Town of Pines, and eastern portions of Great Marsh to 

Lake Michigan. 

Land use in the study area is principally residential along 

streets in Beverly Shores and Town of Pines, and is a mixture 

of residential and commercial uses along US-12 and US-20. 

Principal transportation land uses that cross the study area 

consist of US-12 and US-20, paved and unpaved secondary 

roads, and railroads. Parts of the study area in INDU and adjacent parkland are maintained as natural and restored wetlands, 

wooded dune, and swale environments.

The climate along the southern shore of Lake Michigan, 

including the study area, is characterized by hot, humid summers and cold winters. The mean precipitation is approximately 36 inches per year (in/yr), including approximately 
Introduction 5

30 to 40 in/yr of snowfall (Midwestern Regional Climate 

Center, 2014). Monthly mean precipitation is lowest in February (approximately 1.5 inches [in.]) and highest in June and 

July (approximately 3.8 in.). The mean January temperature 

is 24 degrees Fahrenheit (°F), and the mean July temperature 

is 73 °F (National Oceanic and Atmospheric Administration, 

1982; Greeman, 1995).

Development of Beverly Shores and the surrounding 

areas began in the mid to late 1800s with the draining of 

several thousand acres of Great Marsh for residential use, use 

as cranberry bogs and production of other agriculture, and 

in raising cattle. Prior to development, the eastern portion of 

Great Marsh had two distinctive natural landmarks, the exact 

location of each is unknown: Fish Lake (presumably located in 

the eastern half of the study area), and Tamarack Bog (presumably located in the southern-central portion of the study area) 

(Plampin and Hamilla, 2011, as cited by Daniel Mason, written commun., 2014). These natural landmarks were drained 

by ditches that were the predecessors of modern day Brown 

and Kintzele Ditches, which were dug sometime prior to 1921. 

In the late 1920s, the construction of roads to allow for the 

development of housing within the area began to divide the 

drained areas of Great Marsh. Such development also included 

the installation of low embankments, drainage pipe, ditches, 

and culverts. Residential homes were developed largely in the 

dunes and interdunal wetlands between Great Marsh and Lake 

Michigan, although some were built in or on the periphery 

of Great Marsh. Many of the homes were built with belowland-surface basements that are equipped with sump pumps to 

maintain a dry subsurface space. When Congress authorized 

INDU in the mid-1960s, much of the acreage in Beverly 

Shores between US-12 and the residential part of the dunebeach complex was included within INDU. Areas along US-12 

and in Beverly Shores were later excluded from INDU. Many 

of the roads that were built through Great Marsh for residential 

development were abandoned between 1979 and 2005. 

Possible future modifications to the local hydrologic system east of Lakeshore County Road may include limiting the 

discharge from Brown Ditch with the creation of flow-control 

structures that would allow water to pool on the upstream side. 

A potential side effect could be a rise in water levels in the surficial aquifer; a rise in the water table could result in groundwater flooding of subgrade structures in surrounding residential areas. Owing to a relatively shallow water table in the area 

surrounding Great Marsh, there is a potential for several areas 

to be susceptible to groundwater flooding in response to rapid 

infiltration of precipitation into the surficial aquifer:

• Northernmost residential areas in Town of Pines along 

US-12. The US-12 corridor lies just to the south of 

Great Marsh. Changes in the water-level elevation due 

to increased or heavy precipitation may lower or flatten 

the hydrologic gradient in this area and in the process 

increase the associated travel time of groundwater 

flowing north from Town of Pines to areas of Great 

Marsh.

• Residential areas in southern parts of Beverly Shores.

Low-lying areas immediately north of Beverly Drive 

and Great Marsh, especially those with subgrade structures, can be subject to groundwater flooding because 

of the relatively shallow water table. Parts of these 

areas experienced groundwater flooding during periods 

of relatively high precipitation in 2006–8.

Two conceptual diagrams illustrate typical interactions 

of precipitation and recharge with changes in groundwater 

levels in a hypothetical unconfined sand aquifer (figs. 3 and 4). 

Precipitation that falls on the land surface, minus losses from 

evaporation and plant transpiration (evapotranspiration), can 

pond at the land surface, run off into surface water, or infiltrate through the unsaturated zone to groundwater as recharge 

(fig. 3). Discharge of water from septic systems, leaky sewers, or irrigation systems also can contribute to recharge. A 

building and its basement can be vulnerable to infiltration and 

groundwater flooding of the basement if the water table rises 

above the basement floor (estimated for the purpose of this 

investigation to occur approximately 7 feet (ft) below the land 

surface) or sump underdrain and if the sump pump is unable 

to withdraw sufficient water to lower the groundwater level 

below basement floors and maintain dry conditions (fig. 3). 

Outflow from the conceptualized surficial aquifer 

shown in figure 4 occurs in the form of groundwater seepage 

directly to ditches, wetlands, and lakes, such as Lake Michigan (fig. 4A) and indirectly to those surface-water bodies 

through ditches or subsurface drains (fig. 4B), or to the atmosphere by seasonal processes such as transpiration (fig. 3). 

Withdrawals from the aquifer occur when water is pumped 

from shallow wells in the surficial aquifer for domestic supply 

and lawn irrigation or by sump pumps used for dewatering 

basements and areas near building foundations (fig. 3B). Sump 

withdrawals of groundwater are typically discharged within 

the same property, so these withdrawals may be essentially 

recycled. Withdrawals from sumps would lower groundwater 

levels near the building and slightly raise nearby groundwater 

levels where the water is discharged but would produce little 

overall change in groundwater levels or flow, particularly 

beyond the immediate area of the property (fig. 3).

The rate and volume of groundwater flow through a 

porous medium, such as in an unconfined sand aquifer, are 

directly proportional to the slope of the water-level surface 

(gradient) and the conductive characteristics of the aquifer to 

water (hydraulic conductivity). A water-table altitude can rise 

because of increased amounts of recharge or decreased amounts 

of groundwater outflow. Recharge can increase when more 

precipitation falls, when snow melts, or when water brought 

into an area increases infiltration to the water table. Discharge of 

groundwater from the hypothetical aquifer can decrease if flow 

to a ditch is reduced by clogging from debris or beaver dams, 

causing water levels to rise in an area of typical groundwater 

discharge, such as a lake, ditch, or wetland (fig. 4C). 
6 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Typical

precipitation

SUMP PUMP

Dewatering 

sump

A. Conceptual diagram of parts of the water budget under the dune-beach complex, dry-weather (October 2002) conditions

Recharge by 

wastewater from leaky

sewer system 

Water table

Home

Evapotranspiration

Saturated zone

below the water table

(Groundwater)

Capillary fringe

Water table

(at higher 

altitude)

Increased

recharge to 

Unsaturated zone water table

Soil zone

Increased 

precipitation

Dewatering 

sump and cone of

depression from 

water withdrawal

B. Conceptual diagram of parts of the water budget under the dune-beach complex, wet-weather (March 2011) conditions

Surface water

supplied from

Lake Michigan

Diagrams modified from Alley and others (1999, fig. 4, p. 6).

Evapotranspiration

Saturated zone

below the water table

(Groundwater)

Capillary fringe

Recharge to 

water table Unsaturated zone

Soil zone

Sewer

system

Home

Basement

Surface water

supplied from

Lake Michigan

Recharge by 

wastewater 

from leaky

sewer system 

Sewer

system

Depth of 

approximately 

7 feet

Depth of 

approximately 

7 feet

Basement

Figure 3. Interactions of precipitation with recharge and groundwater levels in a hypothetical unconfined sand aquifer. 

(Note that precipitation in A is less than in B.)
Introduction 7

A. 

B.

Surface-water 

divide 

Groundwater divide 

Ditch

or wetland 

Lake 

Confining unit 

Surface-water 

divide 

Lake 

Tile drain

(water flows 

out of diagram 

into ditch) 

Water table 

affected by 

groundwater

withdrawal by 

a tile drain

Confining unit 

Groundwater divide 

Surficial aquifer 

Surficial aquifer 

Ditch

and wetland 

C. 

Surface-water 

divide

Groundwater divide Ditch

and wetland 

Lake 

Water table 

and groundwater 

divide affected by 

higher wetland 

water level

Confining unit 

Surficial aquifer 

Diagrams reproduced and modified from 

Grannemann and others (2000, fig. 5, p. 5).

Water table 

affected by 

natural 

recharge

Groundwater 

divide 

Water table 

Water table 

Water table 

Groundwater-flow direction

Groundwater-flow direction

Groundwater-flow direction

Figure 4. Generalized groundwater flow. A, Under natural conditions. B, Affected by tile drain flow. C, Affected by surface-waterlevel change in adjacent discharge ditch. (Note that surface-water and groundwater divides coincide in A but not in B or C.)
8 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Groundwater and Surface-Water 

Resources

Many factors affect the hydrology in the study area. 

Groundwater flow is influenced by the hydraulic properties of 

the geologic units that constitute the local aquifers, in addition 

to the timing and quantity of recharge. Topography, streams, 

ditches and wetlands, and climate affect surface-water flow. 

Groundwater- and surface-water flow systems are in close 

hydraulic connection, especially in the highly permeable 

surficial geologic materials.

Hydrogeologic Setting

The study area lies within the Calumet Lacustrine Plain 

physiographic province (Malott, 1922). Gray (2000) refers to 

the same area as the Lake Michigan Border. The province is 

characterized by dune-beach complexes—areas that contain 

many individual dunes with total relief of 50–100 ft between 

the tops and bottoms of adjacent dune lowlands, but with 

water tables that do not follow the dune topography because 

of the highly permeable dune materials (fig. 5). These dunebeach complexes were deposited over the area formerly occupied by glacial Lake Chicago, formed during the Holocene 

Epoch, and represent relic shorelines from when post-Pleistocene Lake Chicago receded (Hartke and others, 1975). Great 

Marsh and associated interdunal wetlands occupy an elongated 

lowland between these dune-beach complexes (fig. 6).

Groundwater resources in the study area are made up 

of the Calumet Aquifer system1

 and, to a lesser extent, the 

Lacustrine Plain Aquifer system1 (fig. 7) and one underlying 

bedrock aquifer system (the Silurian-Devonian Carbonate 

Aquifer system1).

The hydrogeologic framework of the study area consists 

of two unconsolidated aquifers that are included in the Calumet Aquifer system—the surficial aquifer and the basal sand 

aquifer—typically separated by variable thicknesses of glacial 

till and lacustrine clay and silt (table 1; Shedlock and others, 

1994, fig. 10). The aquifer materials beneath the study area are 

made up of approximately 0–110 ft of unconsolidated glacial, 

lacustrine, eolian, and paludal sediments that were deposited 

on a bedrock surface modified by pre-Pleistocene erosion. 

1

 Aquifer-system names are local usage; see Beaty (1994).

The unconsolidated material is thinnest in areas in the northeast part of the study area near the intersection of Kintzele 

Ditch with Lake Michigan; it is generally thickest beneath 

the Beverly Shores duneland that parallels Lake Michigan. 

The underlying bedrock consists of the Antrim and Ellsworth 

Shale of Late Devonian to Early Mississippian age underlain 

by Devonian limestones and dolomites of the Muscatatuck 

Group.

The surficial aquifer consists primarily of lacustrine and 

wind-blown sands and is commonly called the Calumet aquifer (Hartke and others, 1975; Shedlock and others, 1994). The 

saturated thickness of the surficial aquifer in the study area 

ranges from approximately 0 to greater than 30 ft. In much of 

the central part of the study area, lowland areas generally have 

relatively thin (from less than 1 to about 8 ft) wetland deposits 

of muck, peat, calcareous clay, and other organic sediments 

at the surface. These organic deposits are associated with 

back-barrier deposits and other former wetland areas associated with higher levels of the post-Pleistocene Lake Chicago 

(Shedlock and others, 1994; Thompson, 1987). Generally, the 

surficial aquifer is unconfined throughout most of the study 

area. In some areas, however, buried organic sediments may 

function as local confining layers for underlying parts of the 

surficial aquifer and also may create perched water tables. 

The basal sand aquifer in the INDU is described as interbedded clay, sand, gravel, and till by Shedlock and others (1994, 

p. 16), who state that its extent is less well known than that of 

other aquifers in the area. Several deep drilled wells intersect 

the basal sand aquifer within the study area (table 2, fig. 8). 

The thickness of the surface organic material in Great 

Marsh was measured by Thompson (1987) using vibracores 

collected within the study area that ranged from 0.8 to 5.4 ft 

thick. Cores with the thickest organic intervals were collected 

near the center of the study area along Lakeshore County 

Road, and the core with the thinnest interval was collected in 

the eastern portion of the study area northwest of the confluence of Brown and Kintzele Ditches. Little other information 

is available regarding the thickness, areal distribution, and 

composition of the surficial organic sediments throughout the 

study area. The pattern in organic thickness is consistent with 

patterns found in similar study areas and consistent with their 

formation in wetland environments on the landward side of 

former beach ridges identified in this area (Lampe and Bayless, 2013; Thompson, 1992). 
Groundwater and Surface-Water Resources 9

HOLOCENE AND TOLLESTON DUNE-BEACH COMPLEX

GREAT MARSH

CALUMET DUNE-BEACH COMPLEX

Brown Ditch

Derby 

Ditch

Kintzele

Ditch LAKE MICHIGAN

CENTRAL

AVE.

20

12 20

12

B

BD-5

BD-3 BD-4

BD-2

BD-1

BD-14 BD-13

BD-12

BD-11 BD-15

BD-16

212

306

305

211

325

T417

T416

T417

GM-30

214

216 215

241G

GM-26 GM-28

GM-33

GM-34`

GM-36

308

307S

274

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

EXPLANATION

732 feet 

532 feet

Land-surface altitude in feet above 

 North American Vertical Datum of 1988

Previously restored wetland area

BD-12 Former U.S. Geological Survey 

 monitoring well with site identifier

A A’ Hydrogeologic section trace— Section A-A’ shown in figure 5; 

 Section B-B’ shown in figure 13

B’

Test hole with site identifier

A

A’

North American Datum of 1983

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Figure 5. Location of study area, hydrologic cross sections, former monitoring wells, and surface-water features in 

the Great Marsh study area, Indiana Dunes National Lakeshore, near Beverly Shores, Indiana.
10 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore 212 306 305 T416 T417 211325

700

HOLOCENE AND

TOLLESTON DUNEBEACH COMPLEX

CALUMET DUNEBEACH COMPLEX

Altitude, in feet above National Geodetic Vertical Datum of 1929

Glacial lacustrine sand—interbedded 

 with layers of silt and clay

Paludal deposits—peat, muck, some marl, 

 and mixtures of peat and sand

Dune, beach, and lacustrine sand

Shale

Carbonate rocks

Till and glacial-lacustrine clay and silt

SURFICIAL

AQUIFER

CONFINING

UNIT

GREAT MARSH

211

Observation well with site identifier—

dashed where test hole; red where

former well

LAKE MICHIGAN

A A’ 321

VERTICAL SCALE GREATLY EXAGGERATED

Approximate groundwater surface

Modified from Shedlock and others (1994)

0

0

1 MILE

1 KILOMETER

650

600

550

500

450

400

350

Regional direction of groundwater flow

BASAL

SAND AQUIFER

EXPLANATION

Local direction of groundwater flow

Figure 6. Hydrogeologic 

section A–A’ showing 

the surficial aquifer, 

confining unit, basal sand 

aquifer, underlying shale 

and carbonate bedrock, 

and local and regional 

directions of groundwater 

flow (modified from 

Shedlock and others, 1994); 

section trace is shown in 

fig. 5.
Groundwater and Surface-Water Resources 11

ILLINOIS

INDIANA

LAKE

PORTER

41° 40'

41° 30'

41° 20'

87° 30' 87° 15' 87°00'

LAKE MICHIGAN

Study area

LAPORTE

INDIANA

86° 45' MICHIGAN

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W 

North American Datum of 1983

0 5 10 MILES

0 5 10 KILOMETERS

Calumet Aquifer system

Aquifer systems of the Lake Michigan Basin—

Approximate extent as mapped by Beatty (1994) 

Lake Michigan Basin boundary 

Lacustrine Plain Aquifer system

Valparaiso Moraine Aquifer system

Valparaiso Outwash Apron Aquifer system

EXPLANATION

Kankakee Aquifer system

Figure 7. Unconsolidated aquifer systems in the Lake Michigan region and the study area, northwestern Indiana. 

Definitions of aquifer-system characteristics can be found in Beaty (1994, pl. 2).
12 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Table 1. Lithostratigraphy of the study area in the context of northwestern Indiana hydrogeologic units.

Lithostratigraphic descriptions

Hydrogeologic-framework designation

This report and Shedlock and others (1994) Beaty (1994)

Fine- to medium-grained dune, beach, eolian, and lacustrine 

sands and gravels (of Holocene and Pleistocene age)

Surficial aquifer Calumet aquifer system

Glacial and lacustrine sands of Pleistocene age, with interbedded clays and silts, including tills of the Lake Border 

Moraine

Confining units, 

Subtill aquifer, 

Confining units, 

Basal sand aquifer

Lacustrine Plain aquifer system

Shale and carbonate rocks of Early Mississippian, Devonian, 

and Silurian age

Bedrock aquifer Silurian-Devonian carbonate 

aquifer system
Table 2. Characteristics of groundwater-monitoring wells in the study area.—Continued[USGS, U.S. Geological Survey; dd mm ss, degrees minutes seconds; NAVD 88, North American Vertical Datum of 1988; WL, discrete water level; PVC, polyvincontinuous water level; GEO, geologic; —, not applicable; SS, stainless steel]

Well 

name

USGS stationidentification 

number

Latitude 

(dd mm ss)

Longitude 

(dd mm ss)

Type of 

data 

collected

Date 

installed 

(month/

year)

Method 

of 

installation

Landsurface 

datum 

(feet above 

NAVD 88)

Measuring-point 

elevation 

(feet above 

NAVD 88)

Casing 

material

Casing 

diameter 

(inches)

Well depth 

(feet below 

landsurface 

datum)

Wel

scree

lengt

(feet

Privately owned monitoring wells used during study

MW101 414056086573701 41 40 56.13 86 57 36.97 WL 07/2006 Auger 619.0 618.71 PVC 2 26 10 

MW102 414050086574501 41 40 50.36 86 57 45.38 WL, CWL 07/2006 Auger 625.3 628.45 PVC 2 29 10 

MW103 414059086574101 41 40 59.69 86 57 41.36 WL 07/2006 Auger 615.4 615.09 PVC 2 24 10 

MW104 414103086572701 41 41 03.11 86 57 27.36 WL, CWL 07/2006 Auger 620.6 622.45 PVC 2 25 10 

MW106 414125086563301 41 41 25.38 86 56 33.07 WL 07/2006 Auger 619.7 621.56 PVC 2 26 10 

MW107 414125086562301 41 41 24.60 86 56 23.36 WL, CWL 07/2006 Auger 615.4 617.5 PVC 2 19 10 

MW109 414116086563101 41 41 15.59 86 56 30.53 WL 07/2006 Auger 612.2 614.12 PVC 2 21 10 

MW110 414129086563601 41 41 28.52 86 56 35.61 WL, CWL 07/2006 Auger 617.4 619.48 PVC 2 22 10 

MW116 414052086575501 41 40 51.65 86 57 54.53 WL 07/2006 Auger 617.9 617.54 PVC 2 23 10 

MW120 414059086581601 41 40 59.09 86 58 15.61 WL 07/2006 Auger 605.0 606.98 PVC 2 18 10 

MW123 414107086573501 41 41 06.85 86 57 34.99 WL, CWL 07/2006 Auger 612.0 613.66 PVC 2 23 10 

Pre-existing USGS monitoring wells used during study

203S 414212086555602 41 42 11 86 55 56 WL 07/1979 Auger 601.67 600.95 PVC 4 33 5 

203D 414212086555601 41 42 11 86 55 56 GEO 07/1979 Auger 602 — PVC 4 191 5 

211S 413957087002602 41 39 54 87 00 25 WL 05/1979 Auger 611 610.85 PVC 4 21 5 

211D 413957087002601 41 39 54 87 00 25 GEO 05/1979 Auger 611 — PVC 4 175 5 

212G 414057087003003 41 40 54 87 00 30 WL 10/1979 Auger 602 601.31 PVC 2 24 3 

212D 414057087003000 41 40 54 87 00 30 GEO 10/1979 Auger 602 NA PVC 4 210 5 

213G 414041086592003 41 40 39 86 59 18 WL 10/1979 Auger 600.17 600.17 Steel 2 12 3 

213D 414041086592000 41 40 41 86 59 18 GEO 10/1979 Auger 600.5 — PVC 4 133 5 

305D 414029087003201 41 40 29 87 00 33 GEO 09/1981 Auger 599 — PVC 4 156 

305B 414029087003204 41 40 30 87 00 33 WL 11/1985 Hand driven 601 597.74 SS 2 6 3 

321 414017087002701 41 40 17 87 00 26 WL 08/1984 Hand driven 596 598.94 SS 2 5 3 

GM-21 414013087000701 41 40 13 87 00 07 WL 07/1979 Hand driven 598.7 600.58 SS 2 5 3 

GM-25 414050086590501 41 40 52.8 86 59 06.0 WL 07/1979 Hand driven 596.7 599.61 SS 2 8 3 

GM-27 414046086583601 41 40 40.83 86 58 36.90 WL 08/1979 Hand driven 609.16 610.22 SS 2 6 3 
Table 2. Characteristics of groundwater-monitoring wells in the study area.—Continued [USGS, U.S. Geological Survey; dd mm ss, degrees minutes seconds; NAVD 88, North American Vertical Datum of 1988; WL, discrete water level; PVC, polyvincontinuous water level; GEO, geologic; —, not applicable; SS, stainless steel] Well name USGS station- identification number Latitude (dd mm ss) Longitude (dd mm ss) Type of data collected Date installed (month/ year) Method of installation Land- surface datum (feet above NAVD 88) Measur- ing-point elevation (feet above NAVD 88) Casing material Casing diameter (inches) Well depth (feet below land- surface datum) Wel

scree

lengt

(feet

Pre-existing USGS monitoring wells used during study—Continued GM-31 414121086571001 41 41 18.95 86 57 12.25 WL 08/1979 Hand driven 609.26 611.40 SS 2 9 3 

GM-35 414151086562701 41 41 51 86 56 27 WL 08/1979 Hand driven 597.33 598.12 SS 2 6 3 

GM-37 414207086561601 41 42 07 86 56 16 WL 08/1979 Hand driven 595.2 596.66 SS 2 5 3 

549 414115086585401 41 41 15.2 86 58 54.1 WL 04/2008 Direct-push drill rig 604.62 605.83 Steel 2 21 2.

551 414126086585101 41 41 26.3 86 58 51.1 WL 07/2008 Direct-push drill rig 607.22 609.62 Steel 2 15 2.

552 414125086583901 41 41 25.5 86 58 39.5 WL 07/2008 Direct-push drill rig 620.04 622.47 Steel 2 28 1.

553 414109086585001 41 41 09.5 86 58 50.8 WL 07/2008 Direct-push drill rig 607.12 609.46 Steel 2 15 2.

554 414102086584801 41 41 02.0 86 58 48.9 WL 07/2008 Direct-push drill rig 600.8 602.97 Steel 2 17 2.

555 414059086593401 41 40 59.2 86 59 34.8 WL 07/2005 Direct-push drill rig 609.05 611.86 Steel 2 19 2.

556 414101086593901 41 41 01.2 86 59 39.5 WL 07/2008 Direct-push drill rig 604.79 606.95 Steel 2 21 2 

557 414104086594101 41 41 04.3 86 59 41.2 WL 07/2008 Direct-push drill rig 609.57 611.95 Steel 2 18 2

558 414108086594101 41 41 08.3 86 59 41.7 WL 07/2008 Direct-push drill rig 605.11 607.65 Steel 2 15 2

559A 414049086592801 41 40 49.2 86 59 28.4 WL 08/2008 Direct-push drill rig 599.62 601.78 Steel 2 12 2.

559B 414049086592802 41 40 49 86 59 28 WL 11/2008 Direct-push drill rig 598.47 600.93 Steel 2 6 2.

560 414100086591801 41 41 00.4 86 59 18.1 WL 07/2008 Direct-push drill rig 607.44 610.04 Steel 2 15 1.

562 414112086591701 41 41 12.6 86 59 17.9 WL 07/2008 Direct-push drill rig 605.16 607.73 Steel 2 12 2.
Table 2. Characteristics of groundwater-monitoring wells in the study area.—Continued[USGS, U.S. Geological Survey; dd mm ss, degrees minutes seconds; NAVD 88, North American Vertical Datum of 1988; WL, discrete water level; PVC, polyvincontinuous water level; GEO, geologic; —, not applicable; SS, stainless steel]

Well 

name

USGS stationidentification 

number

Latitude 

(dd mm ss)

Longitude 

(dd mm ss)

Type of 

data 

collected

Date 

installed 

(month/

year)

Method 

of 

installation

Landsurface 

datum 

(feet above 

NAVD 88)

Measuring-point 

elevation 

(feet above 

NAVD 88)

Casing 

material

Casing 

diameter 

(inches)

Well depth 

(feet below 

landsurface 

datum)

Wel

scree

lengt

(feet

USGS monitoring wells installed for this study

601 414114086581601 41 41 13.7 86 58 16.4 WL 05/2012 Hand driven 603.27 606.16 Steel 2 18 3 

602 414130086580301 41 41 29.8 86 58 04.0 WL 05/2012 Hand driven 603.41 606.16 Steel 2 8 3 

603 414132086574101 41 41 31.30 86 57 41.3 WL, CWL 05/2012 Hand driven 603.51 606.54 Steel 2 6 5 

604 414140086571501 41 41 41.1 86 57 15.9 WL 05/2012 Hand driven 598.77 601.22 Steel 2 4 3 

605 414152086564901 41 41 52.28 86 56 48.87 WL 05/2012 Hand driven 596.38 599.28 Steel 2 9 3 

606 414124086574101 41 41 26.4 86 57 40.7 WL, CWL 05/2012 Hand driven 602.19 604.92 Steel 2 9 3 

607 414200086563402 41 42 00.09 86 56 34.04 WL, CWL 05/2012 Hand driven 593.64 596.77 Steel 2 8 3 

608 414154086563102 41 41 55.7 86 56 33.7 WL, CWL 05/2012 Hand driven 594.63 598.47 Steel 2 9 3 

609 414139086574101 41 41 38.6 86 57 41.2 WL, CWL 05/2012 Hand driven 603.03 605.67 Steel 2 5 3 

610 414146086562301 41 41 45.3 86 56 21.7 WL, CWL 05/2012 Hand driven 605.25 607.40 Steel 2 6 3 
16 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Brown Ditch

Derby Ditch

Kintzele

Ditch LAKE MICHIGAN

Beverly Shores

LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

Town of Pines

Michigan City

20

12

12

12

20

20

STATE PARK ROAD

203S

MW107

MW106

MW110

GM-31

MW104

MW102

552 551

553 562

560

559A

559B

557

556 555

212G 511

305B

212D

211D

213D

213G

203D

305D

CENTRAL

AVE.

ME2148

INDIANA DUNES

STATE PARK

321 GM-21

211S

GM-27

GM-25

554

601

MW120

602

MW123

604

605 GM-35

GM-37

608

607

606

603

609 610

FLOWING WELL

Study Area

INDIANA

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

EXPLANATION

Indiana Dunes National Lakeshore (INDU) 

Pre-existing U.S. Geological Survey (USGS) monitoring well with site identifier

Model boundary

USGS monitoring well installed for this study with site identifier

Privately owned monitoring well with site identifier

GM-21

601

MW120

Dashed line indicates monitoring well with continuous data collected

North American Datum of 1983

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

ME2148 Benchmark with site identifier

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Figure 8. Location of study area and groundwater-data-collection sites in the Great Marsh study area, Indiana Dunes 

National Lakeshore, near Beverly Shores, Indiana.
Groundwater and Surface-Water Resources 17

Methods of Investigation

A data-collection network was installed in the study 

area to measure both discrete and continuous groundwater 

and surface-water altitudes and streamflow discharge. 

Groundwater-flow modeling relied on these data and hydrogeologic data from previous investigations for its calibration 

and verification. Most of the hydrogeologic interpretations 

in this report are based on data collected from sites shown in 

figures 8 and 9, particularly the following: 

• Lithologic and discrete water-level data collected from 

four monitoring wells and lithologic and continuous 

water-level data collected from six monitoring wells 

installed in May 2012 for this study (table 2).

• Lithologic and discrete water-level data collected 

from six monitoring wells and continuous water-level 

data collected from five monitoring wells previously 

installed (July 2006) and operated in Town of Pines 

by AECOM environmental consultants for previous 

studies in the area (table 2) (AECOM, 2010). 

• Lithologic or discrete water-level data collected from 

30 monitoring wells installed by the USGS before 

2007 for previous studies in the area (table 2). 

• Artesian groundwater discharge measured from the 

“flowing well,” a well developed in the basal sand 

aquifer near Beverly Shores (fig. 8).

• Surface-water stage (water level) obtained from seven 

surface-water monitoring sites, discrete discharge 

obtained from eight surface-water monitoring sites 

established for this study, and continuous discharge at 

three USGS streamgages (table 3). 

Lithology, as referred to in this report, is defined by the 

relative grain size or texture of geologic materials encountered 

during drilling. “Continuous record” indicates data collected 

hourly or more frequently. “Discrete data” indicates measurements made occasionally and not on a set time period.

The lithology data from monitoring wells primarily used 

within the study area were augmented by lithologic information from 27 records from the Water Well Record Database 

maintained by the Indiana Department of Natural Resources 

(IDNR)-Division of Water (Indiana Department of Natural 

Resources, 2014).

All methods used for drilling, finishing, and developing 

monitoring wells installed for this study were consistent with 

USGS procedures and techniques as described in Holmes and 

others (2001) and Lapham and others (1997). Hand-driven 

wells were installed by using an 85-pound (lb) fenceposttype driver. Well casings were galvanized steel pipe and 

stainless steel mesh screens. All monitoring wells used in the 

study were composed of polyvinyl chloride (PVC) plastic, 

galvanized or stainless steel casings, and screens of varying 

diameter (table 2). 

Measuring points for most surface-water-stage measurement sites (table 3) consisted of staff gages or painted or lightly 

chiseled marks on culvert tops that facilitated consistent tape 

measurements down to the water surface (fig. 10). . 

Vertical control on measuring-point altitudes was established with an automatic (pendulum) level and leveling rod by 

using standard methods and procedures (U.S. Geological Survey, 

1966). Measuring-point altitudes for all newly installed monitoring wells, some pre-existing wells, and most surface-water 

stage-measurement sites in the study area (tables 2 and 3) were 

tied to a single first-order benchmark (ME2148, fig. 8) by using 

a starting altitude referenced to North American Vertical Datum 

of 1988 (NAVD 88). Measuring-point altitudes derived by using 

this benchmark are considered accurate to ± 0.01 ft. Measuringpoint altitudes for the 500 series observation wells, and observation wells 203S, 212G, 213G, 211S, 321, 305B, GM-21, and 

GM-25 were originally referenced from National Geodetic 

Vertical Datum of 1929 (NGVD 29) in previous investigations 

(Buszka and others 2011). These NGVD 29 altitudes were converted to NAVD 88 referenced altitudes using a correction factor 

obtained from the National Geodetic Survey VERTCON tool 

(Mulcare, 2004). The reported correction factor was evaluated by 

running an automatic level line from the established first-order 

benchmark referenced to NAVD 88 to a previously established 

reference point referenced to NGVD 29 to ensure that the 

difference between measured elevations agreed within 0.01 ft 

to the reported correction factor. Well-construction information 

and measuring-point altitudes for wells in the AECOM Town of 

Pines network were taken from the Remedial Investigation report 

for the Pines Area of Investigation prepared by AECOM (2010). 

Two observation wells in the AECOM network (MW123 and 

MW104) were included in the optical level line establishing the 

measuring point altitudes of the new observation wells, and 

altitudes determined during that effort agreed with altitudes 

reported by AECOM. 

Water levels in monitoring wells and at surface-water stagemeasurement sites were measured with an electric water-level 

tape or graduated folding rule. All water-level measurements are 

considered accurate to ± 0.01 ft and were made by using standard 

methods and procedures of the USGS (Cunningham and Schalk, 

2011). The stage values for the elevation of Lake Michigan water 

surface were obtained at a National Oceanic and Atmospheric 

Administration (NOAA) monitoring site at Calumet Harbor, Illinois (National Oceanic and Atmospheric Administration, 2011), 

approximately 18 miles (mi) northwest of the study area. 

Continuous record water-level data at groundwaterobservation wells were measured at 1-hour increments during 

June 2012–August 2013 at 11 sites within the study area (fig. 8). 

Vented 10-pounds per square inch (1b/in2

) pressure transducers 

were installed in wells MW102, MW104, MW107, MW110, 

MW123, 603, 606, 607, 608, 609, and 610. Accuracy of the 

transducer measurements of water levels was approximately 

± 0.01 ft. Transducer measurements of water levels were 

adjusted for mechanical drift by linearly averaging the difference 

between the transducer and electrical tape measurements over 

the period between electrical tape measurements.
18 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

C601E

C601

SG-1

BD-TRAIL

BD-CENT

BD-CAR

KD-BEV

04095154

04095158

04095100

DD-MARSH

DD-DUNE

DD-LAKE

BD-RR

KD-TRAIL

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

EXPLANATION

Indiana Dunes National Lakeshore (INDU) 

Surface-water stage-measurement site with site identifier

Model boundary

Arrow indicating direction of surface-water flow

Surface-water discharge-measurement site with site identifier

SG-1

04095100

DD-DUNE

U.S. Geological Survey streamgage with station identification number

Study Area

North American Datum of 1983

INDIANA

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Brown Ditch

Derby Ditch

Kintzele

Ditch LAKE MICHIGAN

Beverly Shores

LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

Town of Pines

Michigan City

20

12

12

12

20

20

INDIANA DUNES

STATE PARK

STATE PARK ROAD

Lakeshore, near Beverly Shores, Indiana.

Figure 9. Location of study area and surface-water data-collection sites in the Great Marsh area, Indiana Dunes National 
Table 3. Characteristics of surface-water data-collection sites in the study area.[USGS, U.S. Geological Survey; dd mm ss, degrees minutes seconds; NAVD 88, North American Vertical Datum of 1988; WL, discrete water level; Q, discrete stream discharg

CQ, continuous discharge]

Site name

USGS 

station-identification 

number

Latitude 

(dd mm ss)

Longitude 

(dd mm ss)

Type 

of data 

collected

Date 

established 

(month/year)

Measuring-point 

elevation (feet 

above NAVD 88)

Surface-water 

body Meas

BD-CAR 414153086562902 41 41 53.39 86 56 29.65 WL 1979 591.36 Brown Ditch Staff gage in Brown 

Carolina Avenue

BD-CENT 414146086563901 41 41 46.89 86 56 39.50 WL 1979 599.79 Brown Ditch Top rim of east side 

flows under Centr

KD-BEV 414204086562401 41 42 04 86 56 24 WL 1982 586.24 Kintzele Ditch Staff gage in Kintze

SG-1 414045086592202 41 40 45 86 59 22 WL 12/2007 595.72 Great Marsh Staff gage in Great M

of Beverly Drive 

C601 414103086581701 41 41 02.9 86 58 16.8 WL 12/2009 601.13 Great Marsh Staff gage just north 

Lakeshore County 

C601E 414103086581702 41 41 03.19 86 58 16.03 WL 05/2012 602.38 Great Marsh Staff gage just north 

shore County Roa

BD-TRAIL 414110086572201 41 41 10.53 86 57 22.13 WL, Q 1979 612.79 Brown Ditch Bridge over Brown D

Measuring point inorth handrail appterminus of handr

KD-TRAIL 414149086560800 41 41 49 86 56 08 Q 1973 — Kintzele Ditch 75 feet downstream 

DD-LAKE 414107086592800 41 41 06.97 86 59 58.30 Q 1973 — Derby Ditch Just north of culvert 

Lake Michigan

DD-DUNE 414050086594701 41 40 50.05 86 59 47.08 Q 03/2013 — Derby Ditch Approximately 1,00

DD-MARSH 414038086593901 41 40 38.96 86 59 39.52 Q 03/2013 — Derby Ditch Just north of Beverly 

04095154 04095154 41 41 46.60 86 56 39.92 CQ 05/2012 594.18 Brown Ditch USGS streamgage lo

Central Avenue

04095158 04095158 41 42 04.81 86 56 24.67 CQ 05/2012 585.16 Kintzele Ditch USGS streamgage lo

Beverly Drive

04095100 04095100 41 41 02 86 59 55 CQ 1978 583.90 Derby Ditch USGS streamgage lo

Fairwater Avenue
20 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

A B

Figure 10. Photographs showing typical surface-water measurement sites. A, Stable culvert end at site BD-CENT. B, Staff gage at site SG1

Artesian groundwater discharge was measured from the 

“flowing well,” a well developed in the basal sand aquifer near 

Beverly Shores (fig. 8). Discharge from the well is continuous to the land surface and, for the purposes of this study, is 

considered a point of recharge to the surficial aquifer. Discharge measurements were made using a graduated cylinder 

and stop watch. Seven consecutive measurements were made 

on September 3, 2013. Results of the measurements were 

averaged to determine the average discharge from the basal 

sand aquifer from the well. Discharge from the well for the 

purposes of this study is assumed to be relatively constant and 

the measurement made on September 3, 2013 to be representative for the period of investigation.

Instantaneous stream discharge was measured in 2012 

at four sites on Derby Ditch, two sites on Brown Ditch, and 

two sites on Kintzele Ditch (fig. 10). All discrete discharge 

measurements were measured by using an acoustic Doppler 

velocimeter. Discharge was calculated from continuous stream 

stage data at two USGS streamgages—one in Derby Ditch 

near the outfall to Lake Michigan (station number 04095100), 

and one on Kintzele Ditch at Beverly Drive (station number 

04095158)—using USGS methods outlined by Rantz and 

others (1982). Discharge was estimated by using hydrograph 

comparison techniques at one USGS streamgage on Brown 

Ditch at Central Avenue (station number 04095154) because 

of complications caused by beaver dams in the ditch at the 

gage location (Rantz and others, 1982). 

Three-dimensional groundwater flow was simulated by 

recreating a groundwater-flow model originally published 

by Shedlock and Harkness (1984) using the finite-difference 

groundwater-model code MODFLOW-NWT (Niswonger and 

others, 2011). The recreated model was checked against previously published results and then modified to better 

represent the current conditions found within the study area. 

The parameter estimation code UCODE_2005 (Poeter and 

others, 2005) was used to improve model calibration. Methods 

used during model reconstruction, modification, and calibration are discussed in detail in the section “Simulation of 

Groundwater Flow and Availability.” A particle-tracking postprocessing package for MODFLOW—MODPATH (Pollock, 

2012)—was used to generate three-dimensional flow paths 

with different scenarios of the model for this report. MODPATH computes paths for imaginary particles of water moving 

through the simulated groundwater system. 

Groundwater Levels and Flow in the Surficial 

Aquifer 

The shallow groundwater flow system is contained within 

the dune deposits and parallels the shoreline of Lake Michigan 

(fig. 5). Water-table mounds form beneath the dune-beach 

complexes on the north side beneath the town of Beverly 

Shores and on the south side beneath Town of Pines (Shedlock 

and others, 1994). Great Marsh, a relatively flat, low lying 

area, lies between both of these water-table mounds. Groundwater flows laterally away from these mounds and generally 

discharges to Lake Michigan to the north, the south branch of 

Brown Ditch to the south, Derby Ditch to the west, Kintzele 

Ditch to the east, and Great Marsh and the north branch of 

Brown Ditch in the center of the study area. The hydraulic 

gradient between Lake Michigan and the water-table mound 

beneath Beverly Shores is very steep (125 feet per mile [ft/mi], 

or 0.28 inches per foot) compared to hydraulic gradients 

between the same water-table mound and Great Marsh to the 

south and between the water-table mound beneath Town of 

Pines and Great Marsh to the north (20 ft/mi or 0.05 in/ft and 

65 ft/mi or 0.15 in/ft, respectively).
Groundwater and Surface-Water Resources 21

Shedlock and Harkness (1984) include synoptic measurements of water-level elevation in August 5, 1982 (table 

4). The authors used these measurements to evaluate the 

original groundwater-flow model. Synoptic measurements2 of 

2

 Synoptic measurements involve data collection at multiple sites in an area 

over a short period (often a single day) to characterize a selected seasonal or 

hydrologic condition.

water-level elevation on March 27, 2013, were used to map 

the water table within the study area and serve as a calibration 

dataset for the modified groundwater model (table 5). Synoptic 

measurements of water-level elevation on April 29, 2014, were 

used to map the water table within the study area during a 

period of time when a beaver dam was in Brown Ditch on the 

upstream side of the culvert beneath Central Avenue at the site 

of USGS streamgage 04095154 (table 5; fig. 10). 

Table 4. Water-level measurements made on August 5, 1982 

(from Shedlock and Harkness, 1984).

[USGS, U.S. Geological Survey; NGVD 29, National Geodetic Vertical 

Datum of 1929]

Site name

USGS 

station-identification 

number

Water-level 

altitude 

(feet above 

NGVD 29)

Abandoned 

as of 2014

Groundwater measurements

214 414147086581900 582.91 Yes

215 414053086544802 616.06 Yes

216 414057086563703 619.69 Yes

274 414228086552001 597.91 Yes

308 414124086583601 601.5 Yes

203S 414212086555602 598.5 No

211S 413957087002602 610.8 No

212G 414057087003003 583.6 No

213G 414041086592003 597.3 No

241G 414004086585003 620.98 Yes

307S 414052086573001 614.83 Yes

GM–25 414050086590501 597.3 No

GM–26 414102086583601 599.5 Yes

GM–28 414101086581801 602.85 Yes

GM–30 414125086574801 604.06 Yes

GM–31 414121086571001 607.48 No

GM–33 414145086570101 598.05 Yes

GM–34 414133086564201 608.06 Yes

GM–35 414151086562701 597.33 No

GM–36 414152086560501 603.3 Yes

GM–37 414207086561601 595.12 No

Surface-water measurements

BD–TRAIL 414110086572201 604.7 No

BD–CAR 414153086562902 594.46 No

KD–BEV 414204086562401 588.9 No
22 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Table 5. Water-level measurements made on March 27, 2013, and April 29, 2014.—Continued

[DV, Daily value interpreted from continuous record; NAVD 88, North American Vertical Datum of 1988; NPS, National Park Service; 

NM, not measured; —, not applicable; USGS, U.S. Geological Survey]

Site name

USGS 

station-identification 

number

March 27, 2013 April 29, 2014 Difference 

between 

April 2014 

and 

May 2013 

measurement

Water-level 

altitude 

(feet above 

NAVD 88)

Agency 

collecting 

measurement

Water-level 

altitude 

(feet above 

NAVD 88)

Agency 

collecting 

measurement

Groundwater measurements

GM–27 414046086583601 608.51 NPS NM — —

GM–31 414121086571001 606.44 NPS 607.21 USGS 0.77

GM–35 414151086562701 596.64 NPS 596.88 USGS 0.24

GM–37 414207086561601 594.61 NPS NM — —

203S 414212086555602 597.82 NPS NM — —

203S 414212086555602 597.81 USGS NM — —

211S 413957087002602 610.25 USGS NM — —

212G 414057087003003 578.50 USGS NM — —

213G 414041086592003 596.97 USGS NM — —

305B–7 414029087003204 596.10 USGS NM — —

GM–21 414013087000701 598.28 USGS NM — —

GM–25 414050086590501 597.21 USGS NM — —

MW–102 414050086574501 613.711 USGS DV 615.10 USGS 1.39

MW–104 414103086572701 609.981 USGS DV 610.67 USGS 0.69

MW–106 414125086563301 611.57 USGS 613.22 USGS 1.65

MW–107 414125086562301 612.451 USGS DV 613.15 USGS 0.70

MW–110 414129086563601 610.951 USGS DV 612.26 USGS 1.31

MW–120 414059086581601 602.98 USGS 603.16 USGS 0.18

MW–123 414107086573501 608.671 USGS DV 609.03 USGS 0.36

321 414017087002701 596.21 USGS NM — —

511 414056086593801 598.07 USGS NM — —

551 414126086585101 599.43 USGS NM — —

552 414125086583901 599.68 USGS NM — —

553 414109086585001 600.68 USGS NM — —

554 414102086584801 598.94 USGS NM — —

555 414059086593401 599.26 USGS NM — —

556 414101086593901 598.75 USGS NM — —

557 414104086594101 598.86 USGS NM — —

559A 414049086592801 597.30 USGS NM — —

559B 414049086592802 597.01 USGS NM — —

560 414100086591801 600.72 USGS NM — —

562 414112086591701 600.16 USGS NM — —

601 414114086581601 603.35 NPS 603.28 USGS –0.07

602 414130086580301 602.62 NPS 603.39 USGS 0.77

604 414140086571501 598.76 NPS 599.45 USGS 0.69

605 414152086564901 596.56 NPS NM — —
Groundwater and Surface-Water Resources 23

Table 5. Water-level measurements made on March 27, 2013, and April 29, 2014.—Continued

[DV, Daily value interpreted from continuous record; NAVD 88, North American Vertical Datum of 1988; NPS, National Park Service; 

NM, not measured; —, not applicable; USGS, U.S. Geological Survey]

Site name

USGS 

station-identification 

number

March 27, 2013 April 29, 2014 Difference 

between 

April 2014 

and 

May 2013 

measurement

Water-level 

altitude 

(feet above 

NAVD 88)

Agency 

collecting 

measurement

Water-level 

altitude 

(feet above 

NAVD 88)

Agency 

collecting 

measurement

Groundwater measurements—Continued

606 414124086574101 602.47 USGS 602.68 USGS 0.21

607 414200086563402 594.08 USGS 594.30 USGS 0.22

608 414154086563102 594.69 USGS 594.90 USGS 0.21

609 414139086574101 601.74 USGS 602.92 USGS 1.18

610 414146086562301 605.24 USGS 605.47 USGS 0.23

Surface-water measurements

BD–TRAIL 414110086572201 602.74 NPS NM — —

C601 414103086581701 601.93 NPS 602.02 USGS 0.09

C601E 414103086581702 603.66 NPS 604.13 USGS 0.47

BD–CAR 414153086562902 592.06 NPS 591.74 USGS –0.32

BD–CENT 414146086563901 595.35 NPS 594.99 USGS –0.36

KD–BEV 414204086562401 586.08 NPS 587.5 USGS 1.42

SG–1 414045086592202 597.04 USGS NM — —
24 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Recharge

Historical precipitation data are available from two stations near the study area: Ogden Dunes, 1951–89 and INDU 

headquarters, 1989–2013 (fig. 11) (Midwestern Regional 

Climate Center, 2014). The Ogden Dunes station was discontinued on May 21, 1989, and relocated to the present INDU 

site, where data collection resumed on June 1, 1989. Figure 11 

shows that precipitation totals in the 3 months prior to the 

March 2013 data collection were higher than typical and 

ranged from 2.34 in. in December 2012 to 3.41 in. in January 

2013. Snowfall for the season was concentrated in the months 

of February and March, with snowpack depths reaching 8 in. 

during the period. Increased temperatures in late March led to 

melting of the snow in the weeks prior to the water-level data 

collection (fig. 12). The growing season, defined for this study 

as the period of time when the mean daily temperature exceeds 

the freezing point, extended from the beginning of data collection to early November 2012 and from early April to early 

November 2013.

August–November 1982 Levels and Flow

During the Shedlock and Harkness (1984) observed 

hydrologic conditions of August 1982, groundwater generally 

flowed to the channels of the ditches within the study area 

from water-table mounds beneath the dune ridges to the north 

and south of Great Marsh (fig. 13). The groundwater divides 

generally coincided with these same dune ridges, but also 

included another divide that oriented northwest-southeast in 

the area just to the east of Lakeshore County Road. 

Shedlock and Harkness (1984) found that the altitude of 

the water-table surface roughly parallels the land surface, and 

that north of Brown Ditch, the water table is virtually flat. A 

hydrogeologic section B-B′ along Carolina Avenue is shown in 

figure 14 (section location shown on fig. 5). Water levels and 

the approximate water-table altitude (in green) shown in the 

figure were measured on November 18, 1982; these wells were 

installed after the previously mentioned August 5, 1982, data 

collection. Groundwater flows north from Town of Pines and 

south from Beverly Shores toward Brown Ditch. 

March 2013 Levels and Flow

Water levels were measured in March 2013 to gain an 

understanding of the hydrologic conditions during a typical 

wet-weather condition in the study area. During the wetweather conditions of March 2013, the major groundwater 

divides (fig. 15) generally coincided with dune ridges that 

parallel Lake Michigan to the north and south of Great Marsh 

in Beverly Shores and Town of Pines, respectively. A secondary groundwater divide trends northwest-southeast just 

east of Lakeshore County Road likely due to the presence of 

Lakeshore County Road that acts as a barrier to groundwater 

flow. Groundwater on the east side of this secondary divide 

flows toward Brown and Kintzele Ditches and ultimately Lake 

Michigan. Groundwater west of the secondary divide flows 

toward Derby Ditch and ultimately Lake Michigan. 

The hydrogeologic section along Carolina Avenue (fig. 

14) shows water levels in the surficial aquifer measured on 

March 27–28, 2013 (in blue). These water levels, except 

those from observation well GM-35, were measured in wells 

installed for this study due to the abandonment of the wells 

along this section used by Shedlock and Harkness (1984). The 

water-table surface is similar to that measured in 1982 south of 

Brown Ditch; the water table roughly parallels the land surface 

and groundwater flows north from US-12 toward Brown 

Ditch. While the water table north of Brown Ditch is relatively 

flat, the measured direction of groundwater flow has reversed 

from the measurements made in 1982 and now flows north 

from the ditch toward Beverly Shores. The hydrologic conditions during the two periods are different, which may explain 

the higher water levels in 2013 south of Brown Ditch, but it 

does not explain the flow reversal north of Brown Ditch. This 

reversal may be due to backwater conditions in Brown Ditch 

due to beaver dams.

Continuous groundwater-level data indicate that the predominant groundwater-flow gradients vary during the course 

of the year (fig. 16; well locations shown on fig. 8). A west 

to east transect of a combination of groundwater-monitoring 

wells and surface-water level monitoring sites indicates that 

the predominant flow direction is from west to east across 

Great Marsh, which follows the drainage gradient of Brown 

Ditch (fig. 16A). A clustering of the data points for groundwater sites 604 and 605 in October 2012 indicates stagnation of 

surface-water flow that may be due to increased precipitation 

or localized obstruction of Brown Ditch flow due to beaver 

dams or debris within Great Marsh. Two north-south trending transects of groundwater and surface-water sites—one 

on the west side of the study area east of Lakeshore County 

Road (fig. 16B), and one on the east side of the study area 

near Kintzele Ditch and the former Carolina Avenue extending south into Town of Pines (fig. 16C)—indicate the predominant groundwater-flow direction was south to north to 

Brown Ditch. The eastern transect shows a gradient reversal 

that occurs in October 2012 when groundwater flows north 

and away from Brown Ditch from well 608 to 607 (fig. 16D), 

which also may be due to increased precipitation or localized 

obstruction of surface-water flow due to beaver dams within 

Great Marsh. The western transect shows two different gradient reversals: one between site 609 and 606, and one between 

606 and 603 (fig. 16E). For the period November 2012–March 

2013 and a smaller period in November 2013, flow is from 

south to north toward site 603 in a smaller wetland area north 

of Great Marsh and Beverly Drive. For the period April–July 

2013 and portions of August 2013, flow is from north to south 

toward 606 within Great Marsh.
Figure 11. Box-and-whisker plots of monthly precipitation statistics for the combined records from the weather stations at Ogden Dunes (1951–89) and Indiana Dunes National Lakeshore, northwestern Indiana (1989–2013), and precipitation from April 2012–December 2013. (Station locations are shown in fig. 1.

05

101520

Monthly precipitation, in inches

October January February April May June July August Sep- March tember Novem- ber Decem- ber

62 60 61 60 61 61 60 61 61 62 6162

2012 2013

Monthly precipitation for 2012–13 March 2013 data collection

April May June July August Sep- October

tember

62 60 61 60 61 61 60 

57 Number of data values in 

 (above top axis) Outlier data value greate interquartile range ou

Whisker, 90th percentile are greater than the va endpoint of the line 

75th percentile

Median

25th percentile

Whisker, 10th percentile greater than the value  of the line 

EXPLANATION
26 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

0

20

40

60

80

100

0

1

2

3

Daily mean temperature, in degrees Fahrenheit Precipitation, in inches

Growing season Growing season

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2012 2013

0

2

4

6

8

10

Snow depth, in inches

Freezing point

Figure 12.. Temperature, precipitation, and snow depth from records from the weather station at Indiana Dunes 

National Lakeshore, northwestern Indiana, May 2012–December 2013
Groundwater and Surface-Water Resources 27

Brown Ditch

Derby Ditch

Kintzele

Ditch

LAKE MICHIGAN

LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA 

DUNES 

STATE PARK

STATE PARK ROAD

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

EXPLANATION

Observation well, with water-level altitude on August 5, 1982, in feet above 

 National Geodetic Vertical Datum of 1929 (NGVD 29)

598.28

610 Water-table contour—Shows approximate altitude of the

 water table in the surficial aquifer system on August 5, 1982. 

 Contour interval is in feet above NGVD 29. Contour interval variable. 

 Modified from Shedlock and Harkness (1984).

Groundwater divide—Approximate divide in surficial aquifer, August 5, 1982

Arrow indicating direction of groundwater flow inferred from water-table contours

597.04 Surface-water-level monitoring site, with water-level altitude on August 5, 1982, 

 in feet above NGVD 29

GREAT MARSH

North American Datum of 1983

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87°01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

610.8

583.6

599.5 602.9

621

616.1

614.8

619.7

624.7

603.3

598.5

597.9

595.1

598.1

608.1

607.5

604.7

594.5 597.3

604.1

606.3

601.5

582.9

600

610

590

620

610

620

610

600

600

590

590600

597.3

Figure 13. Altitude of the water table in the surficial aquifer measured on August 5, 1982, during dry-weather conditions, in 

the vicinity of Great Marsh, Indiana Dunes National Lakeshore, near Beverly Shores, Indiana (modified from Shedlock and 

Harkness, 1984).
28 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Tan sand

Gray sand

Smooth gray clay

Peat

EXPLANATION

BD−14

BD−13

BD−12

BD−11

GM–35

BD−15

BD−16

RAILROAD

BED

Brown Ditch

US-12

VERTICAL EXAGGERATION X 25

BD–14 Observation well with site identifier —

 Green identifier indicates former U.S. Geological Survey

 observation well.

Confining unit

Surficial

aquifer

580

590

600

610

620

0

0

250 500 750 1,000 FEET

250 METERS

BEVERLY DRIVE

Groundwater surface on March 27−28, 2013

Direction of groundwater flow in surficial aquifer —

 Green arrow is direction measured on November 18, 1982.

 Blue arrows are directions measured on March 27−28, 2013.

GREAT MARSH

Altitude, in feet above North American 

Vertical Datum of 1988

B B' 610 608 607

Modified from Shedlock and Harkness (1984)

Groundwater surface on November 18, 1982

Figure 14. Hydrogeologic section and water-table altitude in November 1982 (in green) and March 2013 (in blue) in the surficial aquifer 

along Carolina Avenue, Indiana Dunes National Lakeshore, near Beverly Shores, Indiana (modified from Shedlock and Harkness, 1984). 

(Location of section shown in fig. 5.)
Groundwater and Surface-Water Resources 29

Brown Ditch

Derby Ditch

Kintzele

Ditch

LAKE MICHIGAN

LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA 

DUNES 

STATE PARK

STATE PARK ROAD

GREAT MARSH

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

North American Datum of 1983

EXPLANATION

Observation well, with water-level altitude on March 27−28, 2013, 

 in feet above North American Vertical Datum of 1988 (NAVD 88)

598.28

610 Water-table contour—Shows approximate altitude of the

 water table in the surficial aquifer system on March 27−28, 2013. 

 Contour interval is in feet above NAVD 88. Contour interval variable. 

 MDashed where approximately located

Groundwater divide—Approximate divide in surficial aquifer, March 27−28, 2013. 

Arrow indicating direction of groundwater flow inferred from water-table contours

597.04 Surface-water-level monitoring site, with water-level altitude on March 27−28, 2013, 

 in feet above NAVD 88

578.5

596.1

596.21

598.28

596.97

597.04

597.21

597.30

597.01

598.07 599.26

598.75

598.86

600.16600.68

598.94 600.72

608.39

602.98

603.71

601.97

603.08

613.71

599.43

599.68

602.59

602.47

602.71

601.74

598.80

606.39

608.67 602.76

609.98

612.45

610.95

611.57

605.24

596.56

593.52

594.08

586.38

594.69

594.57 597.81

610.25

605

600

595

590

580

610

596.68

595.25

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Figure 15. Altitude of the water table in the surficial aquifer measured on March 27–28, 2013, during wet-weather conditions, 

in the vicinity of Great Marsh, Indiana Dunes National Lakeshore, near Beverly Shores, Indiana.
30 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

A. East-west transect of five wells and one surface-water monitoring site.

584

586

588

590

592

594

596

598

600

602

604

606

Water-level altitude, in feet above North American 

Vertical Datum of 1988

601

606

604

605

607

KD-BEV

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2012 2013

0

1

2

3

Precipitation, in inches

March 27 synoptic

Figure 16. Hydrographs of continuous water-level altitude in 11 wells and discrete water-levels at 6 sites, 

May 2012–December 2013, near Great Marsh, Indiana Dunes National Lakeshore, Indiana. A, East-west 

transect of five wells and one surface-water monitoring site. B, North-south transect of six wells just east 

of Lakeshore County Road. C, North-south transect of six wells and one surface-water monitoring site.

D, Subset of the sites shown on figure 16B of three wells and one surface-water monitoring site detailing 

gradient reversals. E, Subset of the sites shown on figure 16C of three wells detailing gradient reversals.
Groundwater and Surface-Water Resources 31

B. North-south transect of six wells just east of Lakeshore County Road.

598

600

602

604

606

608

610

612

614

616

Water-level altitude, in feet above North American 

Vertical Datum of 1988

609

MW102

MW104

MW123

603

606

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2012 2013

0

1

2

3

Precipitation, in inches

March 27 synoptic

Figure 16, continued. Hydrographs of continuous water-level altitude in 11 wells and discrete waterlevels at 6 sites, May 2012–December 2013, near Great Marsh, Indiana Dunes National Lakeshore, Indiana. 

A, East-west transect of five wells and one surface-water monitoring site. B, North-south transect of 

six wells just east of Lakeshore County Road. C, North-south transect of six wells and one surfacewater monitoring site. D, Subset of the sites shown on figure 16B of three wells and one surface-water 

monitoring site detailing gradient reversals. E, Subset of the sites shown on figure 16C of three wells 

detailing gradient reversals.
32 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

C. North-south transect of six wells and one surface-water monitoring site. 

590

592

594

596

598

600

602

604

606

608

610

612

614

Water-level altitude, in feet above North American 

Vertical Datum of 1988

MW107

MW110

MISSING DATA

610

GM35 608

607

BD−CAR

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2012 2013

0

1

2

3

Precipitation, in inches

March 27 synoptic

Figure 16, continued. Hydrographs of continuous water-level altitude in 11 wells and discrete waterlevels at 6 sites, May 2012–December 2013, near Great Marsh, Indiana Dunes National Lakeshore, Indiana. 

A, East-west transect of five wells and one surface-water monitoring site. B, North-south transect of 

six wells just east of Lakeshore County Road. C, North-south transect of six wells and one surfacewater monitoring site. D, Subset of the sites shown on figure 16B of three wells and one surface-water 

monitoring site detailing gradient reversals. E, Subset of the sites shown on figure 16C of three wells 

detailing gradient reversals.
Groundwater and Surface-Water Resources 33

D. Subset of the sites shown on figure 16B of three wells and one surface-water monitoring site 

detailing gradient reversals.

599

600

601

602

603

604

Water-level altitude, in feet above North American 

Vertical Datum of 1988

603

606

609

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2012 2013

0

1

2

3

Precipitation, in inches

March 27 synoptic

Period of gradient reversal when groundwater flows south 

from observation well 609 to observation well 606

Period of gradient reversal when groundwater flows north 

from observation well 606 to observation well 603.

EXPLANATION

Figure 16, continued. Hydrographs of continuous water-level altitude in 11 wells and discrete water-levels 

at 6 sites, May 2012–December 2013, near Great Marsh, Indiana Dunes National Lakeshore, Indiana. A, Eastwest transect of five wells and one surface-water monitoring site. B, North-south transect of six wells just 

east of Lakeshore County Road. C, North-south transect of six wells and one surface-water monitoring site.

D, Subset of the sites shown on figure 16B of three wells and one surface-water monitoring site detailing 

gradient reversals. E, Subset of the sites shown on figure 16C of three wells detailing gradient reversals.
34 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

E. Subset of the sites shown on figure 16C of three wells detailing gradient reversals.

599

600

601

602

603

604

Water-level altitude, in feet above North American 

Vertical Datum of 1988

603

606

609

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2012 2013

0

1

2

3

Precipitation, in inches

March 27 synoptic

Period of gradient reversal when groundwater flows south 

from observation well 609 to observation well 606

Period of gradient reversal when groundwater flows north 

from observation well 606 to observation well 603.

EXPLANATION

Figure 16, continued. Hydrographs of continuous water-level altitude in 11 wells and discrete water-levels 

at 6 sites, May 2012–December 2013, near Great Marsh, Indiana Dunes National Lakeshore, Indiana. A, Eastwest transect of five wells and one surface-water monitoring site. B, North-south transect of six wells just 

east of Lakeshore County Road. C, North-south transect of six wells and one surface-water monitoring site.

D, Subset of the sites shown on figure 16B of three wells and one surface-water monitoring site detailing 

gradient reversals. E, Subset of the sites shown on figure 16C of three wells detailing gradient reversals.
Groundwater and Surface-Water Resources 35

Continuous groundwater-level data indicated recharge to 

the surficial aquifer during January–March 2013 from melting 

and infiltration of the winter snowpack, precipitation, and the 

decrease in evapotranspiration during the winter months. Continuous and discrete groundwater-level data presented in figure 

16 for May 2012–December 2013 show that water levels 

gradually increase from October 2012 through March 2013. 

The gradual increase is followed by a period of relatively 

stable water levels from mid-March 2012 through May–June 

2013, followed by a decrease in water levels into the fall. 

Continuous groundwater-level data compared with the 

annual growing season and land-surface elevation at the 

monitoring well for 12 specific sites located in Great Marsh 

indicate the presence and duration of a physical wetland 

condition (appendix 1) and can be used in interpreting biological data, verifying wetland class, and diagnosing potential 

stressors (U.S. Environmental Protection Agency, 2002). One 

of the requirements for an area to be designated a jurisdictional wetland is that the water table is within 1 ft of the land 

surface for 14 consecutive days during the annual growing 

season (U.S. Army Corps of Engineers, 2012). For each plot in 

appendix 1, the altitude of the land surface above NAVD 88 at 

the observation well is indicated by a horizontal green line. An 

altitude 1 ft lower than the land surface altitude is indicated 

by a red line and the area between is shaded grey. The annual 

growing season also is represented on the hydrographs as 

green shaded areas. 

At the beginning of the study in May 2012, observation well sites 601, 602, 603, 604, 606, 607, 608, and GM-35 

had water levels within 1 ft of the land surface altitude, but 

levels decreased below the 1 ft threshold by July 2012 due to 

increased transpiration from vegetation and lack of prolonged 

significant precipitation in the area during the months of April, 

May, and June (figs. 11 and 12). In contrast, water levels in 

monitoring well 605 maintained altitudes within 1 ft of the 

land surface. Near the end of the 2012 growing season, water 

levels at all 12 sites rebounded to near the land surface due 

to increased precipitation, decreased evapotranspiration in 

October, and the construction of beaver dams and debris jams 

located in Great Marsh and Brown Ditch. 

Prior to the beginning of the growing season in April 

2013, water levels at 11 of the 12 sites were above or within 

1 ft of the land surface with the only exception being well 

609, which is located in an interdunal wetland north of Great 

Marsh. Water-levels at all 12 sites continue to be within 1 ft of 

the land surface until August 2013 due to lower than normal 

precipitation in July and August 2013 (fig. 11). Water levels 

increase near the end of the growing season in November due 

to increased precipitation in October and November 2013 and 

the decrease in transpiration associated with the end of the 

growing season. 

April 2014 Levels and Flow

Hydrologic conditions were measured again on April 

29, 2014, in response to the installation of a large beaver dam 

in Brown Ditch just upstream of Central Avenue (figs. 17 

and 18). The hydrologic conditions observed were generally 

similar to the conditions observed during March 2013. Major 

groundwater divides coincided with dune ridges that parallel 

Lake Michigan to the north and south of Great Marsh in 

Beverly Shores and Town of Pines, respectively. A secondary 

groundwater divide trended northwest-southeast just east of 

Lakeshore County Road. Groundwater on the east side of this 

secondary divide flows toward Brown and Kintzele Ditches 

and ultimately toward Lake Michigan. 

A B

Figure 17. Photographs showing A, a beaver dam located at U.S. Geological Survey (USGS) streamgage 04095154 in Brown Ditch 

on the upstream side of Central Avenue, and B, a beaver dam in relation to the staff gage located at USGS streamgage 04095154. The 

comparison was used to estimate the altitude of the top of the beaver dam from the known elevation of the staff gage. 
36 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Brown Ditch

Derby Ditch

Kintzele

Ditch

LAKE MICHIGAN

LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA DUNES 

STATE PARK

STATE PARK ROAD

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

EXPLANATION

Observation well, with water-level altitude on April 29, 2014, 

in feet above North American Vertical Datum of 1988 (NAVD 88)

598.28

610 Water-table contour—Shows approximate altitude of the 

water table in the surficial aquifer system on April 29, 2014. 

Contour interval is in feet above NAVD 88. Contour interval variable. 

Dashed where approximately located

Groundwater divide—Approximate divide in surficial aquifer, 

April 29, 2014.

Arrow indicating direction of groundwater flow inferred 

from water-table contours

597.04 Surface-water-level monitoring site, with water-level altitude 

on April 29, 2014, in feet above NAVD 88

Location of beaver dam in Brown Ditch

North American Datum of 1983

605 607.21

600

595

590

580

610

596.88

615.10

610.67

613.22 613.15

612.26

603.16

609.03

603.28

603.39 603.44 599.45

602.68

594.30

594.90

602.92 605.47

602.02

604.13

591.74

587.50

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Figure 18. Altitude of the water table in the surficial aquifer measured on April 29, 2014,during wet-weather conditions in the 

vicinity of Great Marsh, Indiana Dunes National Lakeshore, near Beverly Shores, Indiana.
Groundwater and Surface-Water Resources 37

Groundwater/Surface-Water Interaction

Several studies describe groundwater flowing from 

areas of recharge in dune-beach complexes downgradient and 

discharging into ditches and ponded areas in the interdunal 

wetlands (Doss, 1993; Shedlock and others, 1994; Winter, 

1999; Lampe and Bayless, 2013). Water levels measured during March 2013 indicate groundwater highs beneath higher 

elevation dune ridges south of US-12 near Town of Pines 

and north of Great Marsh beneath Beverly Shores (fig. 15). 

Groundwater-flow paths indicate that groundwater moves from 

these areas of groundwater highs to areas of lower elevation 

and lower groundwater altitudes like those in Great Marsh. The 

discrete record water-level data collected at monitoring well 

605 (fig. 8; appendix 1) indicate that during the dry months 

(July–October 2012) water-level altitudes remained high, while 

water levels decreased in nearby monitoring wells 604 and 607. 

This may be due to the presence of beaver dams in Brown Ditch 

and their effect on increasing water levels in the wetland to the 

north, or it may indicate the effect of groundwater discharging 

to Great Marsh near well 605. 

Continuous water-level data collections at sites 603, 606, 

and 609 during November 2012–November 2013 (fig. 16A) 

may show the effects of the transient change in the water table 

along the margins of wetlands. In early November 2013, directions of groundwater flow are south from well 603 to well 606 

and Great Marsh. The direction of groundwater flow reverses 

north in late November due to falling water levels in well 603. 

This condition continues through the relatively dry winter 

months until March 2013 when the groundwater-flow direction 

returns south once again when water levels in well 603 rise 

above those of well 606. This condition continues until early 

November 2013 when water levels in well 606 rise above 

those of well 603 and groundwater-flow directions reverse 

again and flow north for a short period of time. The period 

of groundwater-flow reversal from November 2012 to March 

2013 coincide with a period of relatively low precipitation.

Shedlock and others (1994) describe similar conditions 

along a north-south trending transect of observation wells 

near the western margin of the current study area. Continuous water-level data were collected from the wells installed in 

the upgradient dunes and along the margins of Great Marsh. 

Gradient reversals and transient water-table mounds were 

observed in wells along the margin of Great Mash following 

precipitation events that sometimes persisted for several days 

(Shedlock and others, 1994, fig. 16). Subtle gradient reversals 

also were observed at the margins of smaller wetlands in dunebeach complexes that usually followed significant rainfall. 

Similarly, climate effects on the configuration of the 

water table in areas near the margins of surface-water bodies 

were simulated by Winter (1983). Winter found that the effects 

of recharge were focused initially in areas where the unsaturated zone was thinnest, raising the water table more rapidly 

than areas where the unsaturated zone was thicker. Over time, 

the water table rises progressively more in areas with thicker 

unsaturated zones. Groundwater-flow gradients can steepen 

and change direction during this process due to this highly 

dynamic water-table distribution creating transient water-table 

mounds in the areas near surface-water bodies. As conditions 

dry, and the effects of recharge dissipate, transient water-table 

mounds recess and groundwater-flow directions shift back to 

the original direction.

Surface-Water Flow

Streamflow was continuously measured at USGS 

streamgages for the length of the project (1) where Derby 

Ditch enters a culvert just upstream of Lake Michigan 

(04095100), (2) where Brown Ditch is crossed by Central 

Avenue (04095154), and (3) where Kintzele Ditch is crossed 

by Beverly Drive (04095158) (table 3). Discrete discharge 

measurements were made for previous projects in the study 

area on July 16, 1982, at three locations on Brown Ditch and 

one location on Kintzele Ditch downstream of the confluence 

of Brown and Kintzele Ditches (table 6). Discharge measurements were made for this study on March 27–28, 2013, at two 

sites on Brown Ditch, two sites on Kintzele Ditch, and four 

sites on Derby Ditch (table 6). 

On July 16th, 1982, during a relatively dry portion of the 

year when 2 of the previous 3 months received below average precipitation, discharge in Brown Ditch just upstream of 

Great Marsh (BD-TRAIL; fig. 10) was 0.89 cubic foot per 

second (ft3/s), increased to 1.06 ft3/s at a site approximately 1 

mi downstream (BD-CENT), and ultimately was measured at 

1.41 ft3/s at a site another 1,000 ft further downstream (BDCAR). Discharge in Kintzele Ditch downstream from the confluence of Brown Ditch (KD-BEV) was measured as 4.38 ft3

/s. 

Discharge was measured in locations of Brown, Kintzele, 

and Derby Ditches on March 27–28, 2013, during a period of 

relatively wet conditions (table 6). Discharge in Brown Ditch 

measured just upstream of Great Marsh (BD-TRAIL) was 

1.78 ft3/s and increased to 3.13 ft3/s at a site approximately 

1.2 mi further downstream (BD-CAR). Discharge in Kintzele 

Ditch measured just upstream of Great Marsh (KD-TRAIL) 

was 3.66 ft3

/s and increased to 7.39 ft3/s at the location of 

USGS streamgage 04095158 just downstream of Great Marsh. 

Discharge in Derby Ditch measured just downstream of Great 

Marsh was 3.56 ft3/s, decreased to 3.44 ft3/s at a site approximately 900 ft downstream, decreased further to 3.22 ft3

/s at 

the location of USGS streamgage 04095100 just upstream of 

where Derby Ditch enters a culvert under Fairwater Avenue, 

and increased to 3.91 ft3/s just upstream of where Derby Ditch 

discharges to Lake Michigan (DD-LAKE). The increase in 

discharge between USGS streamgage 04095100 and DDLAKE is mostly due to the addition of water from tile drains 

from areas within Beverly Shores to Derby Ditch within the 

culvert (Egler and others, 2013).

Groundwater seepage to Brown Ditch was calculated 

from both sets of discharge measurements. Estimated groundwater seepage to Brown Ditch was calculated by dividing the 

difference between the furthest upstream and downstream 
38 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Table 6. Discrete discharge measurements from streams and ditches in the study area.

[USGS, U.S. Geological Survey; ft3/s, cubic feet per second; —, not applicable]

USGS stationidentification 

number

Site name Water body Date

Measured 

discharge

(ft3

/s)

Instrument 

reported 

percent error

(percent)

Change from 

upstream 

station

(percent)

1982

414110086572201 BD-TRAIL Brown Ditch 7/16/1982 0.89 5 —

414146086563901 BD-CENT Brown Ditch 7/16/1982 1.06 8 19.10

414153086562901 BD-CAR Brown Ditch 7/16/1982 1.41 5 58.43

414204086562401 KD-BEV Kintzele Ditch 7/16/1982 4.38 5 —

2013

414110086572201 BD-TRAIL Brown Ditch 3/27/2013 1.78 10 —

414153086562901 BD-CAR Brown Ditch 3/27/2013 3.13 2.2 76.12

414149086560800 KD-TRAIL Kintzele Ditch 3/27/2013 3.66 1.9 —

04095158 — Kintzele Ditch 3/27/2013 7.39 5 101.73

414038086593901 DD-MARSH Derby Ditch 3/28/2013 3.56 3.7 —

414050086594701 DD-DUNE Derby Ditch 3/28/2013 3.44 4.5 -3.39

04095100 — Derby Ditch 3/28/2013 3.22 6.8 -9.67

414107086592800 DD-LAKE Derby Ditch 3/28/2013 3.91 2.5 —

discharge measurements by the length of the stream channel 

between the measurement sites. This value was then multiplied 

by the total stream reach length to give an estimated groundwater seepage. Two sets of calculations were made using 

low- and high-end estimates of discharge measurement error 

to produce a range of estimate values. Seepage is estimated as 

1.11–1.42 ft3/s along Brown Ditch between sites BD-TRAIL 

and BD-CAR on July 16, 1982, and 1.26–1.46 ft3/s on 

March 27, 2013, between the same two sites. 

The percent of surface-water flow contributing to Kintzele Ditch from Brown Ditch can be estimated by dividing the 

measured discharge from the site just upstream of the confluence of Brown Ditch and Kintzele Ditch (BD-CAR) from 

the discharge measured in Kintzele Ditch just downstream 

of Great Marsh (KD-BEV). In July 1982, Brown Ditch was 

estimated to contribute approximately 32 percent of the total 

flow in Kintzele Ditch. In March 2013, Brown Ditch was estimated to contribute approximately 42 percent of the total flow 

in Kintzele Ditch. The 10 percent increase in total flow from 

1982 to 2013 may be due to the difference in observed climate 

conditions in the study area. 

Groundwater seepage to Kintzele Ditch was calculated 

from only the 2013 set of discharge measurements due to the 

unavailability of a discharge measurement at site KD-TRAIL 

in July 1982. The groundwater seepage rate to Kintzele Ditch 

was calculated by subtracting the measured flow from Brown 

Ditch at BD-CAR from the difference between the furthest 

upstream and downstream discharge measurements (KDTRAIL and 04095158). Two sets of calculations were made 

using low- and high-end estimates of discharge-measurement 

error to produce a range of estimate values. The seepage rate is 

estimated to be from −0.07 to 1.13 ft3

/s, where negative values 

indicate seepage from the ditch to the aquifer. The mean 

value (0.53 ft3/s ) was then divided by the length of the stream 

channel between the upstream and downstream Kintzele 

Ditch measurement sites to determine the approximate gain 

per stream foot of 2.65 × 10-4 ft3/s. This value is similar to the 

calculated gain per stream foot estimated for Brown Ditch in 

both 1982 and 2013. 

The 2013 set of discharge measurements in Derby Ditch 

were used to calculate the volume of water that Derby Ditch 

contributed to the surficial aquifer between measurement 

sites. The difference in discharge between sites DD-MARSH 

and 04095100 was divided by the length of the stream channel between the two sites to determine the approximate loss 

per stream foot. Two sets of calculations were made using 

low- and high-end estimates of discharge measurement error 

to produce a range of estimate values. The range in stream 

loss between DD-MARSH and 04095100 was −0.26 to −0.42 

ft3

/s. The difference in the measured discharge between sites 

04095100 and DD-LAKE (0.58–0.81 ft3/s) represents the volume of water contributed from the Beverly Shores tile drain to 

the flow of Derby Ditch.

Continuous surface-water discharge and surface-water 

elevation was measured at USGS streamgages on Brown, 

Kintzele, and Derby Ditches (fig. 10). Continuous daily 

discharge data collected for Derby and Kintzele Ditches 

from May 2012 to December 2013 is provided in figure 19. 

Monthly mean discharge for Kintzele Ditch for June 2012–

September 2013 is available in table 7.
Groundwater and Surface-Water Resources 39

10−1.0

100.0

101.0

102.0

2

3

4

5

6

7

9

2

3

4

5

6

8

2

3

4

5

6

7

9

10–1.0

100.0

101.0

102.0

103.0

2

3

4

5

7

9

2

3

4

5

7

9

Streamgage USGS 04095100 Derby Ditch at Beverly Shores, Indiana

Streamgage USGS 04095158 Kintzele Ditch at Beverly Shores, Indiana

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2012 2013

Discharge, in cubic feet per second Discharge, in cubic feet per second

8

7

9

8

6

8

2

3

4

5

7

9

6

8

2

3

4

5

7

9

6

8

8

6

Figure 19. Daily value discharge data for May 2012–December 2013 from two streamgages. A, U.S. Geological Survey 

(USGS) 04095100, Derby Ditch at Beverly Shores, Indiana. B, USGS 04095158, Kintzele Ditch at Beverly Shores, Indiana.
40 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

The monthly mean discharge statistics presented in 

table 7 indicate that during the period of record, streamflow in 

Kintzele Ditch was lowest in July 2012 (0.97 ft3/s), and highest during April 2013 (29.20 ft3

/s). In Derby Ditch, streamflow 

also was lowest in July 2012 (0.17 ft3/s), and highest during 

April 2013 (9.36 ft3/s). 

The calculation of discharge at a continuously recording 

streamgage site relies on a stable control structure through 

which the water can flow and be measured. Continuous 

discharge could not be calculated from data collected at USGS 

streamgage 04095154 on Brown Ditch due to the repeated 

construction and removal of beaver dams at the gage site creating continuously changing control and backwater conditions. 

However, the percentage of water Brown Ditch contributes to 

total flow in Kintzele Ditch was estimated by comparing the 

hydrographs of the two sites during the typically dryer fall and 

winter seasons, and the typically wetter spring and summer 

seasons (Rantz and others, 1982). Flow from Brown Ditch is 

estimated to be approximately 40–50 percent of the total flow 

in Kintzele Ditch during the typically dryer fall and winter 

season, and approximately 6–8 percent during the wetter 

spring and summer season. 

Table 7. Monthly mean discharge for U.S. Geological Survey 

station numbers 04095100, Derby Ditch at Beverly Shores, 

Indiana; and 04095158, Kintzele Ditch at Beverly Shores, Indiana.

[USGS, U.S. Geological Survey; ft3/s, cubic feet per second; —, not applicable]

Month

Monthly mean discharge 

 at USGS station number 

04095158

(ft3

/s)

Monthly mean discharge 

at USGS station number 

04095100 

(ft3

/s)

Year Year

2012 2013 2012 2013

January — 3.04 — 1.36

February — 6.48 — 4.16

March — 9.47 — 5.54

April — 29.20 — 9.36

May — 11.70 — 3.15

June 2.03 18.30 0.26 4.58

July 0.97 9.35 0.17 2.13

August 1.14 4.62 0.18 0.49

September 1.17 1.36 0.18 0.20

October 3.72 — 0.25 —

November 1.17 — 0.26 —

December 2.14 — 0.53 —

Hydrologic Modeling Parameters From Previous 

Studies

Results from several hydrologic investigations in or near 

the modeled area and the INDU yielded information about 

local hydrogeology, groundwater, surface-water levels, and 

flows that affected the design of this study (table 8). These 

studies relate to the study area because of similarities in hydrogeologic setting and climatic conditions. Some characteristics 

of the groundwater model developed for this study are based 

on conceptual elements and hydrologic properties determined 

or derived by these previous investigations.

Shedlock and Harkness (1984) used numerical simulations to examine the potential obstruction of surface-water 

flow in Brown Ditch and to compute the effects of ditch 

dredging on the water table. The study was prompted by 

groundwater flooding in basements in a nearby residential 

area during the spring season and a desire to generally lower 

the water table. Simulated water-table declines in response to 

simulated ditch dredging ranged from 0.2 to 2.0 ft depending 

on the ditch configuration.

Lampe and Bayless (2013) used numerical simulations 

to examine the effects of urban development and ditching on 

groundwater and surface-water interaction in and around the 

Long Lake watershed in the INDU west unit, approximately 

8 mi west of the Brown Ditch watershed. The study was 

prompted by groundwater flooding in basements in a nearby 

residential area and by the proposed closing of the discharge 

of US-12 ditch, a major drainage ditch in the watershed. Simulated modifications to the control structure for US-12 ditch 

resulted in decreases in the discharge of US-12 ditch by up to 

61 percent.

Marie (1976) examined a 3.36-square mile (mi2

) area 

about 6 mi west of the Brown Ditch watershed that was 

considered for dewatering as part of the construction of a 

power-generation facility. Numerical simulations of that 

groundwater-flow system indicated that an extensive cone of 

depression would be created by sustained pumping and that 

interdunal ponds about 0.15 mi away on INDU property could 

become dry. 

Meyer and Tucci (1979) examined the effects of seepage 

to the surficial aquifer from fly-ash settling ponds and construction-related dewatering on groundwater levels in the 

Cowles Unit at the INDU, approximately 5 mi west of the 

Brown Ditch watershed. The study area was similar to that 

described in Marie (1976). Results of numerical simulations of 

steady-state conditions characteristic of those in October 1976 

indicated that observed groundwater-level rises in the park 

(as much as 10 ft) were likely a result of water seeping from 

nearby fly-ash settling ponds; seepage of as much as 2 million 

gallons per day (Mgal/d) was estimated by the simulation. 

The same groundwater-flow model was used to explore the 

hydrology at a proposed construction site. The construction 

site was surrounded by a slurry wall and was being dewatered 

to facilitate construction. Results of the simulations indicated 

that water levels were being lowered at INDU, outside of the 
Groundwater and Surface-Water Resources 41

Table 8. Hydrologic parameters used or estimated from field measurements in previous studies in northwestern Indiana.[in/yr, inches per year; ft/d, feet per day; ft3/s, cubic feet per second; <, less than]

Reference

Precipitation 

(in/yr)

Groundwater 

recharge 

(in/yr)

Groundwater 

recharge 

(in/yr)

Storage 

coefficient

Vertical 

hydraulic 

conductivity 

of surficial 

aquifer 

(ft/d)

Hydraulic 

conductivity 

of streambed 

(ft/d

Hydraulic 

conductivity 

of confining 

unit 

(ft/d)

Vertical 

hydraulic 

conductivity 

of confining 

unit 

(ft/d)

Hydraulic 

conductivity 

of carbonate 

bedrock 

(ft/d)

Hydraulic 

conductivity 

value used 

to simulate 

open water 

(ft/d)

Porosity 

of 

surficial 

aquifer

Leakage 

rate of 

sewer 

(ft3/s)

Estimated hydraulic parameter values used in simulations in and around the study area

Marie (1976) 37 8.4–9.2

Meyer and Tucci (1979) 0–9 167 0.0002 16.7 6.7 ×10–3 8.6×108 0.3

Shedlock and Harkness 

(1984)

50

Fenelon and Watson 

(1993)

35 2–17 <1–180 3–4 1 0.0003– 

0.0006

0.0002– 

0.0030

0.01–70 0.4 15–50

Lampe and Bayless (2013) 5.6–7.9 21.34 3 17.6 7,000

Measured hydraulic parameter values in and around the study area

Rosenshein and Hunn 

(1968)

13 0.003–0.12

Kay and others (1996) 0.65–360

slurry containment, by groundwater seepage through or under 

the wall. Notably, field data indicated that groundwater flow 

was generally in the vertical direction from below. Gillies and 

Lapham (1980) reconfigured the numerical model by Meyer 

and Tucci (1979) in response to updated data and a new con-

figuration of hypothetical water withdrawals from the aquifer. 

The water levels simulated by Gillies and Lapham (1980) did 

not substantially differ from those documented in Meyer and 

Tucci (1979). 

Kay and others (1996) used slug-test results from wells 

completed in the surficial sand aquifer to describe the hydro-

geology and determine the horizontal hydraulic conductivity 

(Kh) of the surficial aquifer near the Grand Calumet River 

and the Indiana Harbor Canal, approximately 20 mi west 

of the Brown Ditch watershed. Values of Kh ranged from 

0.65 to 360 feet per day (ft/d), with most values ranging from 

2.1 to 30 ft/d. These slug-test-derived values also were in fair 

agreement with Kh estimated from nearby specific-capacity 

tests, which ranged from 8.0 to 130 ft/d and had a mean value 

of 60 ft/d. The mean Kh computed from specific-capacity-test 

data is about double the values calculated from the slug-test 

data. Differences in the values can relate to differences in the 

method of analysis, the volume of aquifer tested, and the loca-

tion of testing.

Fenelon and Watson (1993) examined the hydrology 

near the Grand Calumet River and the Indiana Harbor Canal, 

approximately 20 mi west of the area examined in this investi-

gation, using measured field data and numerical simulations. A 

contour map of water-level altitudes indicated a groundwater 

divide that paralleled the shoreline and separated groundwater 

flowing south to the Grand Calumet River from that flowing 

north to Lake Michigan. Results of the numerical simulations 

indicated that groundwater discharged about 15 ft

3

/s to leaky 

sewers, 10 ft

3

/s to the Grand Calumet River, 4 ft

3

/s to Lake 

Michigan, and 0 to 10 ft

3

/s to the underlying bedrock. Ground-

water leakage into the sewers varied from 15 to 50 ft

3

/s, but 

these estimates were based on generalized locations of sewer 

lines and their elevations relative to the water table. Fenelon 

and Watson (1993) stated, 

The recharge rate of the Calumet aquifer is virtually 

unknown; values of 4 to 23 in/yr were used by inves-

tigators in several modeling studies of the aquifer. 

Estimating recharge rates in a given area is complicated 

by urban and industrial development, which increases 

surface-water runoff and lowers recharge rates. 

Precipitation and recharge rates mentioned in Fenelon 

and Watson (1993) include a precipitation rate of 35 in/yr 

(National Oceanic and Atmospheric Administration, 1986–87) 

and recharge rates of 13 in/yr (Rosenshein and Hunn, 1968) 

and 4–23 in/yr (Meyer and Tucci, 1979; Warzyn Engineering, 

Inc. 1987; Watson and others, 1989) depending on land use. In 

Fenelon and Watson (1993), the recharge was varied from 

2 to 17 in/yr depending on land use. Shedlock and others (1994) 

indicated that the bedrock in the eastern part of their study area 

probably discharges some water up through the clay unit.
42 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Simulation of Groundwater Flow 

A groundwater model was used to simulate the groundwater-flow system in the vicinity of Great Marsh, INDU to 

establish a better understanding of the effects that proposed 

drainage modifications can have on the hydrologic system in 

the area. The simulations were intended to help the NPS and 

other local stakeholders manage and protect the resources 

within the study area. A specific objective in developing the 

model was to understand the interaction of water levels in 

Great Marsh and Brown Ditch with groundwater levels in 

nearby areas. Since the model published by Shedlock and 

Harkness (1984) adequately simulated surface water/groundwater interactions in the vicinity of Brown Ditch, it was 

recreated as a starting point for simulations in this study. This 

section describes 

• the reconstruction of the model originally published by 

Shedlock and Harkness (1984) including a comparison 

of the reconstructed model results with those of Shedlock and Harkness,

• the conceptual model of the hydrogeology used to 

guide modifications made to the reconstructed model 

and the simplifying assumptions made in the design of 

the modified model, 

• discretization in the modified model of the groundwater-flow system, boundary conditions, stresses, and 

hydraulic properties,

• calibration of the modified model to measured conditions, 

• the sensitivity of the model results to model input, 

• the presentation of results from the modified model in 

the form of simulated water-table contours and flow 

paths,

• the results of scenarios that illustrate the effects of different drainage modifications and climatic conditions 

on the hydrology near Great Marsh, and

• the limitations and qualifications associated with the 

results.

The groundwater-flow system was modeled by using the 

MODFLOW-NWT computer code for simulating groundwater flow of uniform density (Niswonger and others, 2011). 

MODFLOW-NWT is a Newton-Raphson formulation for 

MODFLOW-2005 created to improve solution of unconfined 

aquifers stand-alone program intended to solve computational 

problems involving nonlinear parts of the unconfined groundwater-flow equation used in the model and to enable cells in 

simulated unconfined parts of the groundwater-flow system to 

dry and rewet as the computer calculations converge to a solution, which is a common occurrence when trying to simulate 

wetland conditions (Niswonger and others, 2011).

Simplifying Assumptions of the Conceptual 

Model

Several simplifying assumptions were used to develop 

the groundwater model. The following assumptions were 

made to represent the geometry, hydraulic properties, and 

other characteristics of the groundwater-flow system under the 

study area:

1. The geologic deposits of the surficial aquifer are generalized as an unconfined sand aquifer.

2. Horizontal and vertical hydraulic conductivity within 

the surficial aquifer are assumed to be uniform throughout the model except in northern areas beneath the 

Holocene Dune-Beach Complex and the Tolleston 

Dune-Beach Complex that join north of Great Marsh 

(fig. 5), where Buszka and others (2011) describe an 

organic muck deposit extending an unknown distance 

and depth beneath the northern dune ridge. Thompson 

(1987) describes that the same northern margin of Great 

Marsh Basin is difficult to define due to sediments of 

the Tolleston complex overlying the sediments of Great 

Marsh. 

3. The surficial aquifer in the model is underlain by a 

confining unit made up of till and glacial-lacustrine clay 

and silt. The surficial aquifer is assumed to be considerably more permeable than the underlying confining unit. 

Flow rates are determined by the thickness and vertical 

hydraulic conductivity of the confining unit and by the 

water-level difference between the surficial sand aquifer 

and the basal sand aquifer.

4. The thickness of all simulated streambeds is assumed to 

be 1 ft. The calibrated value of vertical hydraulic conductivity of the streambed is based on this 1 ft streambed 

thickness.

5. The groundwater-flow system is assumed to be in 

dynamic equilibrium. Dynamic equilibrium is defined as 

a water-level fluctuation above and below a long-term 

mean water level. The starting water levels are assumed 

to be at steady-state and not in any long-term rise or fall.

6. A third-party high resolution light detection and ranging 

(lidar) dataset was used to represent the land surface of 

the groundwater-flow model. Lidar does not penetrate 

areas of open water. Land-surface elevations of the dataset in areas known to be inundated were field verified 

during data collection and were evaluated to be accurate. 

The elevations are assumed to be accurate throughout 

the simulation extent, but some inconsistencies within 

the groundwater-flow model and the evaluation of the 

simulated water-table altitudes may occur in areas that 

were inundated during lidar data collection. 
Simulation of Groundwater Flow 43

Reconstruction of the Original GroundwaterFlow Model

The original groundwater-flow simulations published 

by Shedlock and Harkness (1984) were conducted using 

the two-dimensional finite-difference model of Trescott and 

others (1976). This model was a precursor to MODFLOW, 

which is the USGS current three-dimensional finite-difference 

groundwater-simulation software package. MODFLOW was 

first published in 1984 and has been updated periodically with 

major releases. All of the simulations discussed in this report 

were completed using MODFLOW-NWT (Niswonger and 

others, 2011). The original model was reconstructed using 

MODFLOW-NWT by a university student under supervision 

of USGS staff. Techniques and a description of the methods 

used were provided by the student in the form of a report 

and are cited in this report as a written communication (Jesse 

Wright, Indiana University-Purdue University Indianapolis, 

written commun., 2012).

The original model grid contained 21 rows and 32 columns and was 1 layer thick (Shedlock and Harkness, 1984, 

fig. 10). All rows were 500 ft wide and columns were of varying size. In the western portion of the grid, cells were 1,000 ft 

wide while columns in the eastern portion of the grid were 

500 ft wide. There was a transition zone of three columns 

between the eastern and western portions where the where the 

cell widths were 600 and 800 ft. The total width (west to east) 

of the model grid was 22,500 ft, while the total height (north 

to south) of the model grid was 10,500 ft. 

Elevation values were assigned to the top of the reconstructed model cells using contours from USGS topographic 

maps (Jesse Wright, Indiana University-Purdue University 

Indianapolis, written commun., 2012). Little information 

is available regarding the bottom-surface elevation of the 

original model. A bottom of aquifer elevation was interpolated 

using driller’s logs from wells pictured in the original report 

figures and data from 27 additional driller’s logs from the 

IDNR Water Well Record Database. This bottom of aquifer 

surface was assigned to the reconstructed model cells.

The surficial aquifer was assumed to be homogeneous 

and isotropic and was assigned a uniform Kh

 value of 50 ft/d, 

following the methods described by Shedlock and Harkness 

(1984). The Kh value of the cells along the south, east, and 

west borders of the reconstructed model grid was specified 

as zero to simulate no-flow boundaries. Ditches in the model 

area were simulated using constant head cells with watersurface elevations assigned using interpolations supplied in 

the original report figures for Brown Ditch (figs. 4, 10, and 11, 

Shedlock and Harkness, 1984) and unpublished data for Kintzele and Derby Ditches collected by the USGS at the time of 

the report and stored with the National Archives and Records 

Administration by the original report authors.

Results of the Reconstructed Model 

The original model documentation by Shedlock and Harkness (1984) only reports results from a dredging experiment where 

the original model is altered to show the effects of deepening the 

upstream east branch of Brown Ditch. Similar alterations were 

made to the reconstructed model to compare the results to those 

presented in the original model report. 

The simulated drawdown using the reconstructed MODFLOW-NWT model differs mostly on the southern side of the 

model south of Brown Ditch and Town of Pines (fig. 20). Contours 

for the reconstructed simulation closely resemble those reported by 

Shedlock and Harkness (1984) in the areas beneath and to the north 

of Town of Pines. Differences to the south may be due to differences in the bottom elevation of the model grid cells used by the 

original model and those in the reconstructed model. The simulation output from the reconstructed model is very similar to the 

original Shedlock and Harkness (1984) model and indicates that 

the reconstructed model adequately recreates the original model. 

Modification of the Original Groundwater-Flow 

Model to Incorporate Current Conditions

In order to more accurately simulate the conditions of the 

study area, a modified groundwater-flow model was developed 

by making the following modifications to the reconstructed 

model. These modifications take advantage of more current 

technology and expanded features of the MODFLOW-NWT 

software package, as well as incorporating additional and more 

current hydrologic and elevation conditions:

• A finer discretization of the same model area,

• Addition of two model layers to simulate ponded surface 

water (layer 1) and vertical flow paths within the surficial 

aquifer (layer 3),

• Implementation of the drain package to simulate the effects 

of surface-water levels in Derby, Brown, and Kintzele 

Ditches on the groundwater system,

• Addition of parameters to simulate spatial differences in the 

hydraulic conductivity distribution within the modeled area,

• Addition of spatial recharge of varying amounts to account 

for the effects of precipitation, evaporation, land use, topographic characteristics, and discharge of groundwater from 

the surficial aquifer through a local flowing well,

• Inclusion of a finer resolution land-surface elevation dataset 

derived from the lidar data,

• Inclusion of groundwater- and surface-water level observations and surface-water discharge observations from the 

study area from March 2013, a relatively wet hydrologic 

condition, as calibration targets to examine the specific 

effects of the condition on the surrounding land uses and to 

assist with sensitivity analysis and estimation of aquifer 

parameters.
44 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Brown Ditch

Derby Ditch

Kintzele

Ditch

LAKE MICHIGAN

LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA DUNES 

STATE PARK

STATE PARK ROAD

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

EXPLANATION

Line of equal water-table decline, in feet, from original groundwater-flow model simulation—

 Results from dredging experiment 1. Presented here for model-verification purposes only. 

 Modified from Shedlock and Harkness (1984).

Model boundary

Line of equal water-table decline, in feet, from reconstructed MODFLOW-NWT model simulation—

 Results from dredging experiment 1. Presented here for model-verification purposes only.

1

1

North American Datum of 1983

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

0.2

0.5

1

1.5

2

0.2

0.5

1

1.5

Figure 20. Comparison of the results of the dredging experiment using the original model published by Shedlock and Harkness 

(1984) to the results of a similar experiment using the reconstructed MODFLOW-NWT model (in red).
Simulation of Groundwater Flow 45

Spatial Discretization

The modified groundwater-flow model is based on a 

rectangular block-centered finite-difference grid network that 

extends approximately 4.25 mi in length and 2.0 mi in width 

(fig. 21). The active grid generally extends to natural boundaries: Lake Michigan on the north, Brown Ditch on the south, 

and Kintzele Ditch to the east. Kintzele and Brown Ditches 

were observed to be perennial streams during the length of this 

study. Areas outside of these boundaries are represented by 

inactive cells and are not simulated by the groundwater model. 

The western and southwestern model boundary is defined 

approximately along a flow line and sufficiently to the west so 

as to not affect simulated flow patterns near the eastern portions of Great Marsh. The model grid contains 105 rows, 

225 columns, and 3 layers for a total of 70,875 cells. All 

model cells measure 100 × 100 ft in horizontal dimension. 

Groundwater flow is simulated by three model layers 

that represent surface water of the model area and the surficial aquifer (fig. 22). Layer 1 represents open-water areas 

of the model including Great Marsh, and is allowed to be 

wet in response to the simulated conditions of the model 

(for example, areas of layer 1 can become wet or dry in 

response to changes in recharge or other model parameters). 

Layers 2 and 3 represent the surficial aquifer. Layers 1 and 

2 were simulated as potentially confined or unconfined, and 

layer 3 is simulated as confined. The bottom of layer 1 represents the land surface of the model area. Lidar data in the form 

of land-surface contours with a 1-ft interval made available by 

the Porter County surveyor’s office was used to compile the 

land-surface layer within the model (Kevin Breitzke, Porter 

County Surveyor, written commun., 2013). Surveyed elevations of the bottoms of Derby, Brown, and Kintzele Ditches 

were used in combination with interpolation techniques to 

assign land-surface elevation values to cells in the model area 

that represent these ditches. The bottom of layer 3 represents 

the top of a till and glacial-lacustrine clay and silt confining 

unit found throughout the study area (Shedlock and others, 

1994). Layer 2 is three-quarters the total simulated thickness 

of the surficial aquifer. Layer 3 is one-quarter the total simulated thickness of the surficial aquifer.

Boundary Conditions

A total of 587 drain cells (McDonald and Harbaugh, 

1988) were used in layer 2 to represent the ditches shown in 

figure 23. Drain cells receive groundwater discharge but do 

not recharge the groundwater system whenever the water table 

falls below the bottom of the drain. A streambed hydraulic 

conductivity of 3.0 ft/d was chosen for the ditches because 

both streambeds were observed to contain sand, peat, muck, 

and organic material and is similar to values used in previous 

investigations (Lampe and Bayless, 2013). Bottom elevations for all of the stream and drain cells were based on field 

measurements made at data-collection sites along the channel 

and interpolated between. While sump pumps are present in 

residential neighborhood areas in the model area, sump withdrawals were not simulated in the model due to their relatively 

small localized impact on the water table.

Boundary conditions in the groundwater model were 

selected so that the type and location of the boundary would 

have minimal effect on simulated flow in the modeled area. 

A constant-flux boundary was used at the top of the model to 

represent recharge as a spatially variable, fixed value for each 

cell. A head-dependent-flux boundary was used at the bottom 

of the model to simulate exchange of vertical flow through 

the silt and clay confining unit separating the surficial aquifer 

from the confined basal sand and bedrock aquifer. As inferred 

from available water levels from the pre-existing USGS monitoring wells installed in the basal sand aquifer (table 2), the 

flow direction is upward from the basal sand aquifer into the 

surficial aquifer in the modeled area. No new water-level data 

were collected from these sites as part of this project. Flow 

rates are determined by the thickness and vertical hydraulic 

conductivity (Kv) of the silt and clay unit and by the waterlevel difference between the surficial aquifer and the confined 

basal sand aquifer. A Kv value of 1.0 × 10–4 ft/d was used, 

which was similar to that used by Lampe and Bayless (2013). 

A no-flow boundary condition was used on the west side of 

the model where groundwater flow is assumed to be parallel to the boundary, as shown in Shedlock and others (1994, 

fig. 14). Kintzele Ditch and upstream reaches of Brown Ditch 

are assumed to be a hydrologic boundary to the flow system 

of the model. A head-dependent flux boundary (consisting of 

drain cells) was placed along the southern and eastern boundaries of the model along these ditches. The bottom elevation 

of the drain cell values were based on the measured elevation 

of the bottom of the ditch. A constant-head boundary was 

placed along the northern edge of the model to represent Lake 

Michigan, and a value of 576.87 ft NAVD 88 as recorded from 

the NOAA monitoring site at Calumet Harbor, Illinois, for the 

period of data collection within the study area.

Initial water levels for all model layers were set at an altitude of 10 ft above the land-surface elevation (top of layer 2), 

which ensured that all model cells would contain water at 

the beginning of the simulation. The depths to groundwater 

generally ranged less than 20 ft throughout the modeled area; 

therefore, simulated water levels did not need to change substantially to final values during the first simulation. 

The sensitivity of the model to features of the model 

design, such as boundary conditions or the extent of the model 

grid, was tested by enlarging the active model grid area to the 

full horizontal extent of the reconstructed model area with 

no applied boundary conditions and comparing those results 

with the results of the calibrated modified groundwater-flow 

simulation. The simulation with the larger active model area 

produced water levels in two areas that were 1 ft or more 

higher than the original model results: areas south of US-12 in 

the western portion of the active model area, and a small area 

in Town of Pines in the southeast portion of the active model 

area near upstream portions of Brown and Kintzele Ditches. 

Both of these areas are located in portions of the model where 
46 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Brown Ditch

Derby Ditch

Kintzele

Ditch LAKE MICHIGAN LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA DUNES 

STATE PARK

STATE PARK ROAD

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

EXPLANATION

Active grid cells within the model boundary

Inactive grid cells within the model boundary

North American Datum of 1983

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Column 52

Column 197

Figure 21. Model grid used in the simulation of groundwater flow in the vicinity of Great Marsh, near Beverly Shores, 

Indiana.
Simulation of Groundwater Flow 47

EXPLANATION

Surficial aquifer zone of hydraulic conductivity

Great Marsh surficial aquifer zone of hydraulic conductivity

Northern Holocene dune ridge surficial aquifer zone of 

hydraulic conductivity

SOUTH NORTH

Layer 3

surficial aquifer

Specified-head

boundary

(Lake Michigan)

Head-dependent-flux boundary

Layer 2

surficial aquifer

Layer 1 (open water)

Brown Ditch

Brown Ditch

Head-dependent 

flux boundary

(Drain Cells) 

GREAT MARSH

Figure 22. Layering design for the model in the vicinity of Great Marsh, near Beverly Shores, Indiana. 
48 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Brown Ditch

Derby Ditch

Kintzele

Ditch LAKE MICHIGAN LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA DUNES 

STATE PARK

STATE PARK ROAD

BEVERLY DRIVE

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

EXPLANATION

Drain cells

Constant-head cells

North American Datum of 1983

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

'

Figure 23. Boundary conditions and drain cells used in the simulation of groundwater flow in the study area.
Simulation of Groundwater Flow 49

boundary conditions are not well defined. Water levels in the 

vicinity of Brown Ditch, Great Marsh, and the residential area 

along US-12 east of Lakeshore County Road were altered by 

less than 0.03 ft. 

The model presented in this report is a modification of a 

previously published model and was constrained to the extent 

of the original model. The sensitivity of the results of the 

simulation to the boundary conditions of the model are presented in this report as a guide that future users of the model 

can use to determine the suitability of the model for future 

investigations. 

Hydraulic Properties

Initial values for the Kh were based on previous reported 

values (table 8) and on other published values for similar 

materials (Freeze and Cherry, 1979; Fetter, 1994). The Kh of 

the surficial aquifer in layers 2 and 3, except for areas beneath 

the northern Holocene dune ridge, was based on aquifer-test 

information from previous studies reported by Kay and others (1996, p. 30) and from groundwater-flow model results 

by Lampe and Bayless (2013). According to Kay and others 

(1996), values of Kh commonly range from 2 to 30 ft/d. Lampe 

and Bayless (2013) reported initial and final model calibrated 

values for the Kh of the surficial aquifer as 30 and 21.34 ft/d, 

respectively. The upper-end value (30 ft/d) was chosen as the 

initial value on the basis of observed aquifer sediment characteristics in the study area. Areas of the northern Holocene dune 

ridge where other studies have reported localized finer grained 

deposits at depth were simulated with lower Kh of 15 ft/d 

for both layers 2 and 3 than the rest of the surficial aquifer 

(Buszka and others, 2011; Thompson, 1987; fig. 24). 

Portions of the model representing wetland areas were 

initially assigned a Kh and Kv value of 20 ft/d based on 

the organic rich nature of the sediments and their probable 

resistance to flow. Following the work of Lampe and Bayless (2013), the Kh

 of open water in layer 1 was initially set 

at 10,000 ft/d to represent the low resistance of flow through 

open water.

Recharge

Initial values of recharge rate were based on previous 

reported values used in groundwater-flow models for similar 

environments in northern and northwestern Indiana, such 

as those of as Meyer and Tucci (1979), Arihood and Cohen 

(1998), Duwelius and others (2001), and Lampe and Bayless 

(2013). Four initial individual recharge rates were assigned to 

areas of the model representing wetlands, the town of Beverly 

Shores, Town of Pines, and other undeveloped areas including 

some areas of low-density development (fig. 25). Recharge 

was applied to the top of the model.

A recharge value applied to a single model cell in the 

western portion of the model just south of Beverly Drive was 

used to simulate the discharge of a flowing well that penetrates the underlying confined aquifer system (fig. 25). A 

value of 533 in/yr was assigned to the cell, which simulates 

the discharge of approximately 9,100 gallons per day (gal/d) 

of water to the land surface as measured on September 3, 

2013. Discharge from the well for the purposes of this study is 

assumed to be relatively constant and the measurement made 

on September 3, 2013 to be representative for the period of 

investigation.
50 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Brown Ditch

Derby Ditch

Kintzele

Ditch LAKE MICHIGAN LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

12

12

20

20

INDIANA DUNES

STATE PARK

STATE PARK ROAD

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

EXPLANATION

Model cells in layers 2 and 3 with horizontal hydraulic 

conductivity values representing undeveloped areas 

Model cells in layers 2 and 3 with horizontal hydraulic 

conductivity values representing wetland areas

Model cells in layers 2 and 3 with horizontal hydraulic conductivity 

values representing the northern Holocene dune ridge

North American Datum of 1983

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Figure 24. Hydraulic conductivity distribution within model area of layers 2 and 3. 
Simulation of Groundwater Flow 51

Brown Ditch

Derby Ditch

Kintzele

Ditch LAKE MICHIGAN LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA DUNES

STATE PARK

STATE PARK ROAD

BEVERLY DRIVE

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

EXPLANATION

Model cells with recharge values representing 

undeveloped areas

Model cells with recharge values representing 

residential areas of Beverly Shores

Model cells with recharge values representing 

residential areas of Town of Pines

Model cells with recharge values representing 

residential wetland areas

Model cell with recharge values representing the 

Beverly Shores flowing well (model cell is at the far 

western edge of the model grid just south of Beverly Drive)

North American Datum of 1983

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01’ 87° 86° 59’ 86° 58’ 86° 57’ 86° 56’ 86° 55’

Figure 25. Location of recharge zones in the town of Beverly Shores, Town of Pines, and other undeveloped and wetland 

areas of the groundwater-flow model; and point representing the discharge of water from the Beverly Shores flowing well.
52 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Model Calibration

Calibration is the process of adjusting the model input 

variables, also called parameters, to minimize the errors or differences between simulated and observed hydraulic heads and 

flows. In this report, the term “head” is used interchangeably 

with water-level altitude (Lohman and others, 1972). Many 

of the model parameters were automatically adjusted during parameter estimation. During calibration of the modified 

groundwater-flow model, parameters were adjusted manually 

at first and then by use of automatic parameter-estimation 

techniques to match hydraulic heads from observation wells 

and streamflow fluxes. (“Streamflow flux” in this case is the 

increase in discharge along a reach attributed to groundwater 

inflow). 

Parameter estimation in MODFLOW-NWT was accomplished with the UCODE_2005 program (Harbaugh, 2005; 

Poeter and others, 2005), which uses a nonlinear least-squares 

regression method to aid in estimating parameters that represent hydrologic properties and to further evaluate the model. 

The parameters estimated during calibration represent the 

hydrologic properties distributed as constant values over broad 

areas or parameter zones, as well as over extended linear features such as ditches. Calibrated parameter values are not necessarily expected to equal or agree with specific values of field 

tests within a given zone of aquifer or stream reach because 

parameters represent hydraulic conditions over broad areas.

Parameter-estimation techniques were used to estimate 

values of hydrologic properties for the groundwater-flow 

simulations; some of those values were then adjusted manually to the final parameter values used in the model. This 

method is explained in great detail in Hill (1998) and Hill and 

Tiedeman (2007). The regression method is a more efficient 

and objective process compared to trial-and-error calibration 

because all parameter values are adjusted automatically and 

concurrently to obtain the best possible fit between observed 

and simulated values. The numerical difference between 

observed and simulated values is called a residual. During the 

parameter-estimation process, parameter values are estimated 

by minimizing the sum of the squared weighted residuals, 

called the objective function. Parameter estimation was manually constrained by the authors so that parameter values used 

for the groundwater simulations would be within a range of 

values expected for the environmental conditions existing in 

the study area. In some cases, parameter estimation resulted in 

the final reported value; but in others, a slight manual trialand-error adjustment of the estimated parameter value resulted 

in new values that achieved lower total root mean square error 

(RMSE) values for both head and flow observations. If manual 

adjustment of a parameter from the estimated value did not 

achieve lower RMSE values, the original parameter estimated 

value was adopted and is reported herein as the final value. 

The model was considered calibrated once the overall fit of the 

groundwater-flow model was near 1 ft (a further discussion is 

available in the “Model Fit to Observations” section). 

Model Parameters

In the model, grid cells assumed to have similar hydrologic properties were grouped together as a parameter zone 

and assigned a single parameter value that was adjusted during 

the calibration process. In all, 14 parameters were used in 

the final model design. Names of the parameters used in the 

model, the model component that each parameter represents, 

and associated values are listed in table 9. 

The sensitivity of simulated water levels to changes in 

model parameters was measured to evaluate which parameters 

could be estimated by means of automated parameter-estimation techniques. The sensitivity of hydraulic heads with respect 

to various model parameters was calculated by using the sensitivity equation method (Hill and others, 2000). Composite 

scaled sensitivities (CSS) and significant correlations between 

parameters were calculated for each parameter (table 9). CSS 

values aid in determining whether there is adequate information in the calibration data to estimate a particular parameter; 

generally, parameters that are highly correlated with other 

estimated parameters cannot themselves be estimated. CSS 

values less than approximately 0.01 times the largest CSS of 

the parameters indicate that the regression may not be able to 

estimate the parameter (Hill, 1998, p. 38; Hill and Tiedeman, 

2007, p. 50). 

Observations and Observation Weights

The observations used for model calibration consisted 

of 36 water-level measurements and 3 streamflow gain/loss 

measurement made in March 2013 (table 10). Of the 36 waterlevel measurements, 30 were made in groundwater-monitoring 

wells and 6 were made using surface-water level sites. Most 

of the water-level measurements were in the vicinity of Great 

Marsh and Brown Ditch on March 27–28, 2013. Streamflow 

gain and loss targets were derived from multiple discrete 

discharge measurements made in Brown, Kintzele, and Derby 

Ditches on the same day as groundwater- and surface-water 

level measurements (table 6). 

Water-level and streamflow gain/loss observations were 

weighted before they were used in model calibration to reduce 

the influence of observations that were less accurate and to 

increase the influence of observations that were more accurate. 

Residuals of water-level observations are reported in units of 

feet, and residuals of streamflow are reported in units of cubic 

feet per second. The weighting process produces “weighted 

residuals” (a measure of the difference between an observation and its corresponding simulated value) that have the same 

measurement units, whether the residual is for water levels or 

streamflow gain/loss. Model calibration that uses water-level 

and streamflow gain/loss residuals in the same measurement 

units allows both types of residuals to be included in the sum 

of squared errors that the automated parameter-estimation 

process attempts to minimize. 
Simulation of Groundwater Flow 53

Table 9. Final parameter values and parameter composite-scaled sensitivities used in the modified model simulations.

Parameter Parameter 

description

Parameter 

type

Parameter 

derived by 

means of 

parameter 

estimation

Correlations 

with other 

parameters

Parameter 

value CSS

kdrn1 Vertical hydraulic conductivity of 

the streambed for the ditch along 

US-12

Drain Yes NC 3.115 ft/d 18.34

kow Horizontal hydraulic conductivity 

assigned to the cells of layer one 

used to simulate areas of the open 

water of East Long Lake and 

West Long Lake

Horizontal hydraulic 

conductivity

No NC 10,000 ft/d 11.60

ks Horizontal hydraulic conductivity 

of the surficial sand aquifer

Horizontal hydraulic 

conductivity

Yes PineRech, 

SandRech, 

MarshRech, 

kwet, BevShoresR

17.73 ft/d 150.64

kBevS Horizontal hydraulic conductivity 

of the surficial sand aquifer of 

northern dune ridge

Horizontal hydraulic 

conductivity

— BevShoresR, 

SandRech, 

kwet, 

MarshRech

14.34 ft/d 266.06

kwet Horizontal hydraulic conductivity 

of the surficial aquifer of Great 

Marsh

Horizontal hydraulic 

conductivity

— SandRech, 

MarshRech, 

BevShoresR

17.82 ft/d 30.62

kvow Vertical hydraulic conductivity 

assigned to the cells of layer 1 

used to simulate areas of the 

open water of East Long Lake 

and West Long Lake

Vertical hydraulic 

conductivity

No NC 10,000 ft/d 0.28

kvs Vertical hydraulic conductivity of 

the surficial sand aquifer

Vertical hydraulic 

conductivity

No NC 5 ft/d 1.58

kvBevS Vertical hydraulic conductivity 

of the surficial sand aquifer of 

northern dune ridge

Vertical hydraulic 

conductivity

— NC 3.0 ft/d 0.48

kvwet Vertical hydraulic conductivity 

of the surficial sand aquifer of 

Great Marsh

Vertical hydraulic 

conductivity

— NC 10 ft/d 2.01

SandRech Recharge rate to the surficial sand 

aquifer in non-urban and nonwetland areas

Recharge Yes MarshRech 14.66 in/yr 170.71

BevShoresR Recharge rate to the surficial sand 

aquifer in urban areas

Recharge Yes SandRech, 

MarshRech

21.97 in/yr 294.26

MarshRech Recharge rate to the surficial sand 

aquifer in wetland areas

Recharge Yes NC −6.91 in/yr 139.46

PineRech Recharge rate to the surficial sand 

aquifer in Town of Pines

Recharge Yes MarshRech, 

SandRech

11.70 ft/d 99.62

flowingWel Recharge values used to simulate 

flow from the flowing well in 

Beverly Shores

Recharge No NC 533 ft/d 0.28
54 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Table 10. Measured (observed) and model-calculated (simulated) water levels and discharge 

measurements used as observations and model residuals for the modified groundwater model.

[NAVD 88, North American Vertical Datum of 1988]

Observation 

name Site type Date Observed value

Simulated 

value Residual

Water level, in feet above NAVD 88

213G Groundwater March 2013 596.97 597.34 −0.37

SG-1 Surface water March 2013 597.04 595.30 1.74

GM-27 Groundwater March 2013 608.39 608.09 0.30

559B Groundwater March 2013 597.01 597.37 −0.36

MW102 Groundwater March 2013 613.71 614.34 −0.63

GM-25 Groundwater March 2013 597.21 596.37 0.84

511 Groundwater March 2013 598.07 597.19 0.88

212G Groundwater March 2013 578.50 578.79 −0.29

MW120 Groundwater March 2013 602.98 604.24 −1.26

555 Groundwater March 2013 599.26 597.86 1.40

560 Groundwater March 2013 600.72 601.72 −1.00

554 Groundwater March 2013 598.94 597.78 1.16

MW104 Groundwater March 2013 609.98 608.84 1.14

C601E Surface water March 2013 603.71 603.95 −0.24

MW123 Groundwater March 2013 608.67 608.03 0.64

553 Groundwater March 2013 600.68 599.79 0.89

BD-TRAIL Surface water March 2013 602.76 603.10 −0.34

601 Groundwater March 2013 603.08 602.92 0.16

GM-31 Groundwater March 2013 606.39 605.39 1.00

606 Groundwater March 2013 602.47 601.68 0.79

MW107 Groundwater March 2013 612.45 612.68 −0.23

MW106 Groundwater March 2013 611.57 612.06 −0.49

552 Groundwater March 2013 599.68 599.84 −0.16

MW110 Groundwater March 2013 610.95 611.39 −0.44

602 Groundwater March 2013 602.59 603.64 −1.05

603 Groundwater March 2013 602.71 602.05 0.66

609 Groundwater March 2013 601.74 603.68 −1.94

604 Groundwater March 2013 598.80 600.07 −1.27

610 Groundwater March 2013 605.24 604.80 0.44

BD-CENT Surface water March 2013 595.25 596.51 −1.26

GM-35 Groundwater March 2013 596.68 595.37 1.31

605 Groundwater March 2013 596.56 597.58 −1.02

BD-CAR Surface water March 2013 592.05 593.47 −1.42

608 Groundwater March 2013 594.69 593.52 1.17

607 Groundwater March 2013 594.08 593.80 0.28

KD-BEV Surface water March 2013 586.38 585.86 0.52

Discharge, in cubic feet per second

Brown Ditch Surface water March 2013 −4.5 -0.79 −3.71

Derby Ditch Surface water March 2013 −3.5 -1.06 −2.44

Kintzele Ditch Surface water March 2013 −2 -0.27 −1.83
Simulation of Groundwater Flow 55

Weights on observation data account for measurement 

error associated with the accuracy of the sampling device, 

method of determining land-surface elevation, effects of recent 

water withdrawals in the vicinity of the observation, uncertainties in the depths of screened intervals of groundwater wells, 

and other factors. In theory, weights on the observations used 

in the regression procedure can be calculated from estimates of 

the variance or standard deviation of measurement error (Hill, 

1998, p. 45–47). The weights are proportional to 1 divided by 

the variance of the measurement errors for the observation. To 

estimate these variances, the UCODE_2005 program applies 

statistics on measurement error from which the variances of 

the observation errors are calculated. The standard deviation 

of the measurement error was used as the statistic to estimate 

the weights for water-level observations, and the coefficient of 

variation was used for the streamflow gain/loss measurements. 

The calculations of the statistics are described in Hill (1998, 

p. 46–47).

Weights for the water-level observations were based on 

the assumption that 95 percent of the measurements were 

within the measurement error, which was considered to be 

0.01 ft. Statistical theory for normally distributed populations 

states that for the 95-percent confidence interval, the measurement error should be 1.96 times the standard deviation of the 

measurement error (Cooley and Naff, 1990, p. 44). The standard deviation of the measurement error is, therefore, equal to 

0.0153 (0.01 divided by 1.96); the standard deviation of the 

measurement error is used as an input to UCODE_2005 for 

calculating water-level weights. The weights for the streamflow observations in Brown, Kintzele and Derby Ditches were 

calculated by using an estimated coefficient of variation value 

of 0.2; this assumes a standard deviation of 20 percent of the 

measurement made at the site.

Simulation Results

This section provides the final calibrated values for 

model parameters for the modified groundwater-flow model, 

indicates how the model simulates observed values of water 

level and streamflow with its calibrated parameter values, 

and presents a simulation of the groundwater-flow system as 

represented by the model. 

Calibrated Parameter Values

The calibrated values for all parameters are listed in 

table 9. The final parameter value for the hydraulic conductivity of the surficial sand aquifer (ks) was 17.73 ft/d, whereas 

the value of the parameter that represents the hydraulic 

conductivity of the less permeable aquifer material beneath 

the northern Holocene dune ridge (kBevS) was 14.34 ft/d. The 

final parameter value that represents the recharge to the aquifer 

system in the undeveloped areas of the model domain (SandRech) is 14.66 in/yr; the recharge to the aquifer system in the 

developed areas of the town of Beverly Shores (BevShoresR) 

and Town of Pines (PineRech) are 21.97 and 11.70 in/yr, 

respectively; and the recharge to the aquifer system in wetland areas of the model domain (MarshRech) is −6.91 in/yr. 

The negative recharge value simulates evaporation from the 

ponded areas of Great Marsh. Lampe and Bayless (2013) also 

simulated wetland areas with lower recharge values than those 

of the surrounding surficial aquifer in a similar setting.

Model Fit to Observations

The calibrated groundwater-flow model accurately 

simulated water levels and streamflow gain/loss in the actual 

flow system during low-flow conditions, as measured by a correlation coefficient of nearly 1.0 between weighted observations of water levels and streamflow gain/loss and weighted 

simulated equivalents computed by the model. The model fit 

between field-observed values and model-simulated values is 

an indication of how well the model simulates the observed 

conditions of the groundwater-flow system. Model fit is 

measured in multiple ways, including correlation coefficients 

of weighted simulated values with weighted observed hydrologic measurements. Residuals, in this case, are the difference between the observed conditions in March 2013 and the 

model-simulated values. Ideally, model values should be close 

to observed values such that when weighted observations are 

plotted against weighted simulated values, the points should 

fall close to a line with slope equal to 1 and intercept of 0. 

The correlation coefficient between weighted observations and 

weighted simulated equivalents reflects how close the points 

plot along the line. A value greater than 0.90 is desirable, and 

the model calibration to the dry-weather data resulted in a 

value of nearly 1.00. A plot of both unweighted simulated values with unweighted observed values and weighted simulated 

values with weighted observed values is shown in figures 26A

and 26B.

The calibrated groundwater-flow model also met two 

other criteria that are required of valid models. The weighted 

residuals or difference of weighted simulated water levels 

and streamflow gain/loss and their weighted observed values 

were determined to plot along a straight line with a correlation coefficient of nearly 1, close to the desired 1:1 relation. 

Two types of weighted-residual plots that illustrate these 

model characteristics are shown in figure 26. In figure 26C, 

the weighted residuals are plotted according to their position 

in an assumed normal distribution. If the weighted residuals are normally distributed, then they should plot along a 

straight line. The statistic that measures the linearity of the 

plot, as well as the independence of one residual from another, 

is called the correlation between ordered weighted residuals 

and normal order statistics. This correlation coefficient also 

should be near 1, and the value associated with the calibration 

is 0.980; the weighted residuals plot generally along a straight 

line. In figure 26D, weighted residuals are plotted with their 

simulated values. Ideally, the weighted residuals should be 

evenly distributed around 0 (no difference between weighted 

simulated and weighted residual values,) and the size of the 
56 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

570 580 590 600 610 620

Observed water level, in feet above NAVD 88

570

580

590

600

610

620

Simulated water level, in feet above NAVD 88

1:1 slope

Water-level value

A

58,000 59,000 60,000 61,000 62,000

Weighted observed water level, in feet above NAVD 88

58,000

59,000

60,000

61,000

62,000

Weighted simulated water level, in feet above NAVD 88

1:1 slope

B

−3 −2 −1 0 1

Normal probability plotting position

−300

−200

−100

0

100

200

300

Weighted residual value, in feet above NAVD 88

2 3

Weighted residual

Weighted water-level value

570 580 590 600 610 620

Simulated water level, in feet above NAVD 88

−300

−200

−100

0

100

200

300

Weighted residual value, in feet above NAVD 88

C D

Simulated water level

Figure 26. Graphical analysis of model fit. A, Simulated and observed water levels. B, Weighted simulated and weighted observed 

water levels. C, Normal probability plot of weighted residuals. D, Weighted residuals and simulated water levels.

weighted residuals should not relate to the magnitude of the 

simulated values (for example, large residuals should not be 

associated with lower simulated values). These requirements 

are generally satisfied.

To display the more important error associated with 

the simulated water levels, the axes on the residual plots on 

figures 26C and 26D were chosen to show only the weighted 

residuals that represent water levels. The residual plots do not 

show the residual associated with measured streamflow gain/

loss because the streamflow gain/loss residual plots near the 

origin of the axis, whereas the water-level residuals plot farther from the origin. Showing all residuals on figures 26C and 

26D would result in clumped data points, and details of the 

distribution of the water-level residuals would be obscured. 

The streamflow gain/loss residuals plotted above the 1:1 line 

for the figure 26C plot and near the zero line for the figure 

26D plot indicating the simulation is underpredicting the 

groundwater discharge to the ditches within the study area. 
Simulation of Groundwater Flow 57

Small overpredictions and underpredictions of water 

levels by the model are relatively scattered in their geographic 

distribution across the model area (fig. 27). Unweighted 

residuals can be analyzed by their areal distribution, range, 

and magnitude; unweighted water-level residuals are the 

actual difference between measured and simulated water levels with no weighting factor applied. The unweighted waterlevel residuals for March 2013 are shown in figure 27 for 

the modified model simulation to depict the mixed nature of 

positive and negative residuals in different parts of the model 

area, which is characteristic of an adequately calibrated model. 

The largest residual values are in areas of greatest relief in 

the northern dune ridge near Beverly Shores or along areas of 

steep banks near ditches where the model grid cell size may 

impact the simulated values due to large variations in topography being averaged within a single model cell. Residuals west 

of Lakeshore County Road in Great Marsh are mostly positive, while residuals on the east side are a mixture of positive 

and negative values. These results indicate that the model is 

simulating observed water-level conditions adequately in the 

area of greatest interest surrounding Brown Ditch. 

Simulated water levels and streamflow gain/loss data 

are very similar to the observed data, as indicated by several 

statistics that compare them. Computed statistics based on the 

unweighted water-level residuals are presented in table 11. The 

range of unweighted water-level residuals can be expressed 

by their standard deviation, and the standard deviation of 

the residuals for the calibration is 0.94 ft. Almost 60 percent 

of the residuals are within 1 standard deviation of the mean 

residual, and all but one are within 2 standard deviations. The 

magnitude of water-level residuals can be represented by the 

mean absolute error, or the mean of the magnitudes of the 

water-level residuals, which is 0.81 ft. The relative accuracy 

of the model calibration can be measured by the percent mean 

absolute error, which is the mean absolute error divided by the 

overall range in water levels. The percent mean absolute error 

for the model was 2.27 percent. 

Simulated residuals of groundwater loss to the ditches 

in the study area indicate that the model underpredicts the 

amount of groundwater that is discharged to the ditches. The 

simulated loss of groundwater to Brown Ditch was 0.79 ft3

/s, 

while the observed estimate based on discharge measurements was 4.5 ft3

/s. The simulated loss of groundwater to 

Derby Ditch was 1.06 ft3/s, while the observed estimate based 

on discharge measurements was 3.5 ft3/s. The simulated loss 

of groundwater to Kintzele Ditch was 0.27 ft3/s, while the 

observed estimate based on discharge measurements was 

2.1 ft3/s. Efforts to decrease the streamflow residuals through 

automated parameter-estimation techniques resulted in the 

increase in water-level residuals with little to no improvement 

to streamflow residuals. This may indicate the error associated 

with the calculation of the gain/loss observations is greater 

than originally believed.

Weighted residuals were used to determine that the 

overall fit of the groundwater-flow model was within 1 ft. 

Weighted residuals can be used to determine a measure 

of model fit for water levels and streamflow gain/loss that 

includes error in the measurement of the observations. The 

weighted residuals are used to calculate the standard error of 

the regression. The standard error of the regression for the 

model is dimensionless, so it is multiplied by the standard 

deviation of water-level measurement error to obtain a measure of overall model fit for water levels. The standard error 

for the model for the dry-weather simulation is 111.90, and 

the standard deviation of measurement error for water levels is 

0.01; therefore, the overall model fit is ± 1.12 (dimensionless). 

Simulated Water Budget

The resulting calibrated model can be quantified and 

analyzed by an overall water budget and by a budget for 

individual parts of the flow system. Table 12 lists the overall 

budget for the modified model simulation. The influx of water 

into the model comes predominantly from aerial recharge values assigned during the calibration process across the extent of 

the model to simulate precipitation and simulated infiltration 

from the filtration pond. To a lesser extent, water also enters 

the model from the confined aquifer below across the headdependent basal boundary. A large portion of the discharge 

from the model goes to Lake Michigan (40 percent), but even 

more discharge enters Brown, Kintzele, and Derby Ditches (44 

percent). A smaller portion (16 percent) of the discharge from 

the model goes to evaporation (negative recharge) simulated in 

the model. 

The budget between the model and four areas of the 

model (fig. 28)—Great Marsh west of Lakeshore County 

Road, Great Marsh east of Lakeshore County Road, Town 

of Pines, and Beverly Shores—was analyzed, and the results 

are shown in table 13. Nearly 100 percent of all water entering the area simulating Town of Pines is from recharge. Of all 

the water simulated to enter the eastern and western portions 

of Great Marsh, nearly 20 and 18 percent, respectively, flows 

from Town of Pines to the western and eastern portions of 

Great Marsh. Less than 1 percent of the water from Great 

Marsh flows south to the aquifer beneath Town of Pines. 

Nearly 3 and 8 percent, respectively, of all water entering 

the eastern and western portions of Great Marsh flows from 

the aquifer beneath Beverly Shores. Less than 1 percent flows 

from Great Marsh south to the aquifer beneath Beverly Shores. 

Nearly 71 percent of all groundwater leaving the Beverly 

Shores simulated area flows into Lake Michigan. 

Approximately 70 percent of the water from both 

simulated areas of Great Marsh is lost to evapotranspiration while approximately 28 to 25 percent, respectively, of 

recharge eventually discharges to ditches for the western and 

eastern Great Marsh. Nearly 10 times more water (0.1 versus 

0.005 ft3

/s) flows from east to west beneath Lakeshore County 

Road between the two simulated Great Marsh areas than flows 

from west to east.
58 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Brown Ditch

Derby Ditch

Kintzele

Ditch

LAKE MICHIGAN

LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA DUNES

STATE PARK

STATE PARK ROAD

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

North American Datum of 1983

EXPLANATION

−0.34

Model boundary

1.74

Location of an observation well with a positive (blue) or negative (red) residual—

At these locations, positive values indicate the groundwater-flow model underestimated 

the water level in the observation well. Negative values indicate the groundwater-flow model 

overestimated the water level in the observation well.

Location of a surface-water elevation monitoring site with a positive (blue) or negative (red) 

residual—At these locations, positive values indicate the groundwater-flow model underestimated 

the water level at the site. Negative values indicate the groundwater-flow model overestimated the 

water level at the site. 

−0.29

−0.37

1.74

0.84

−0.36

0.88 1.40

0.89

1.16

−1.00

0.30

−1.26

−0.24

0.16

−0.63

−0.16

−1.05

0.79

0.66

−1.94

−1.27

1.00

0.64

−0.34

1.14

−0.23

−0.44

−0.49

0.44

−1.02 −1.42

0.28

0.52

1.17

1.31

−1.26

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Figure 27. Difference between observed and simulated water levels for the modified groundwater-flow model of the Great 

Marsh area near Indiana Dunes National Lakeshore, Indiana. 
Simulation of Groundwater Flow 59

Table 11. Computed statistics based on the water-level and gain/loss residuals for the modified groundwater-flow model.

[ft, feet; ft3/s, cubic feet per second]

Statistics based on unweighted model residuals

Type of 

residual

Minimum 

residual 

(ft)

Mean 

residual 

(ft)

Maximum 

residual 

(ft)

Standard 

deviation of 

the residuals 

(ft)

Bias 

(ft)

Mean 

absolute 

error 

(ft)

Percent 

mean 

absolute 

error

Water level –1.94 0.04 1.73 0.94 1.52 0.81 2.27

Type of 

residual

Drainage 

feature 

name

Observed 

(ft3

/s)

Simulated 

(ft3/s)

Residual 

(ft3/s)

Streamflow Brown Ditch –4.5 –0.79 –3.71

Streamflow Derby Ditch –3.5 –1.06 –2.44

Streamflow Kintzele Ditch –2.1 –0.27 –1.83

Table 12. Water budget associated with the modified groundwater-flow model.

[ft3/s, cubic feet per second; >, greater than]

Inflow to model Inflow rate (ft3/s) and 

percent of total

Outflow from model Outflow rate (ft3/s) and 

percent of total

Lake Michigan (constant-head 

boundaries)

0 0.00 Lake Michigan (constant-head 

boundaries)

1.94 40.08

Leakage into Brown Ditch, Kintzele Ditch, 

and Derby Ditch (model drains)

2.12 43.8

Confined aquifer (headdependent boundary4.29 × 10-6 >1 Confined aquifer (head-dependent 

boundary)

1.14 × 10-8

Precipitation (recharge) 4.84 100.00 Evaporation (recharge) 0.77 >1

Total inflow 4.84 Total outflow 4.84 15.91
60 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Brown Ditch

Derby Ditch

Kintzele

Ditch LAKE MICHIGAN LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA DUNES 

STATE PARK

STATE PARK ROAD

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

North American Datum of 1983

EXPLANATION

Zone 1 representing Great Marsh west of Lakeshore County Road

Zone 2 representing Great Marsh east of Lakeshore County Road

Zone 3 representing Town of Pines

Zone 4 representing Beverly Shores

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Figure 28. Zones representing Great Marsh west of Lakeshore County Road, Great Marsh east of Lakeshore County Road, the 

town of Beverly Shores, and Town of Pines used in the estimates of individual water budgets and groundwater-flow interactions 

with the modified groundwater-flow model of the Great Marsh area near Indiana Dunes National Lakeshore, Indiana.
Simulation of Groundwater Flow 61

Table 13. Water budgets for four zones of the groundwater-flow model simulating Great Marsh west of 

Lakeshore County Road, Great Marsh east of Lakeshore County Road, the town of Beverly Shores, and 

Town of Pines.

[ft3/s, cubic feet per second; —, not applicable]

West Great Marsh 

Zone 1

East Great Marsh 

Zone 2

Town of Pines 

Zone 3

Beverly Shores 

Zone 4

Water moving into cells 

Rate, in ft3

/s (percent of total flow)

From Recharge Zone 0 2.194

(74.35%)

1.09

(73.96%)

1.77

(99.83%)

2.69

(99.01%)

From West Great Marsh 

Zone 1

— 0.005

(0.34%)

0.00

(0.00%)

0.02

(0.74%)

From East Great Marsh 

Zone 2

0.1

(3.32%)

— 0.002

(0.11%)

0.007

(0.26%)

From Town of Pines 

Zone 3

0.58

(19.52%)

0.26

(17.72%)

— —

From Beverly Shores 

Zone 4

0.084

(2.85%)

0.12

(7.91%)

— —

Total (ft3

/s) 2.95 1.47 1.78 2.72

Water moving out of cells

Rate, in ft3

/s (percent of total flow)

To Lake Michigan — — — 1.94 

(71.41%)

To ditches 0.83 

(28.06%)

0.36 

(24.81%)

0.61 

(34.52%)

0.31 

(11.55%)

To Recharge Zone 0 2.1 

(71.06%)

1.00 

(67.96%)

0.33 

(18.41%)

0.26 

(9.64%)

To West Great Marsh 

Zone 1

— 0.1 

(6.68%)

0.58 

(32.43%)

0.58 

(32.43%)

To East Great Marsh 

Zone 2

0.005 

(0.17%)

— 0.26 

(14.64%)

0.12

(4.27%)

To Town of Pines Zone 3 0.00 

(0.00%)

0.002 

(0.14%)

— —

To Beverly Shores 

Zone 4

0.02 

(0.68%)

0.007 

(0.48%)

— —

Total (ft3

/s) 2.95 1.47 1.78 2.72
62 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Simulated Water Levels and Groundwater-Flow 

Paths

The results of the calibrated, modified groundwater-flow 

model indicate that the dune ridges beneath Town of Pines and 

to a lesser extent beneath Beverly Shores are a major source 

of recharge to the surficial aquifer and Great Marsh under the 

conditions observed during March 2013. The groundwaterflow system can be illustrated by water-level contours from 

which direction of flow can be inferred. Simulated water-level 

contours are presented in figure 29 for the modified groundwater-flow model. The major simulated flow paths are north 

from the dune ridges beneath Town of Pines toward Great 

Marsh and Brown Ditch. To a lesser extent, groundwater in the 

simulation flows south from the dune ridge beneath Beverly 

Shores to Great Marsh and Brown Ditch. Groundwater also 

is simulated to flow north from areas beneath Beverly Shores 

and discharges to Lake Michigan. 

A predominant groundwater divide in the calibrated 

simulation runs east from Derby Ditch parallel to the dune 

ridge beneath Beverly Shores to Kintzele Ditch in the eastern 

portion of the modeled area. A secondary groundwater divide 

in the calibrated simulation runs southeast from approximately 

the intersection of Beverly Drive and Lakeshore County Road 

and terminates near the southern boundary of Great Marsh. 

Groundwater is simulated to flow east of this minor divide 

toward Brown Ditch and west to Derby Ditch. Groundwater 

discharges to Brown Ditch in the calibrated simulation where 

it cuts through the dune ridge beneath Town of Pines and is 

intercepted by the ditch as it flows north from Town of Pines 

toward Great Marsh on the eastern side of the modeled area. 

Groundwater discharges to Derby Ditch where it cuts through 

the dune ridge beneath Beverly Shores. Groundwater also 

discharges to Derby Ditch as the ditch flows north from Town 

of Pines toward Great Marsh on the western side of the modeled area. 

Groundwater-flow paths, which are perpendicular to the 

water-level contours, provide useful information about the 

source, distribution, and discharge of groundwater. Backward 

tracking flow paths were generated in nodes3

 representing 

Brown Ditch, Kintzele Ditch, Derby Ditch, and the Lake 

Michigan shoreline using MODPATH (Pollock, 2012); results 

are shown in figure 30. MODPATH, a particle-tracking postprocessing package for MODFLOW, computes paths for 

imaginary particles of water moving through the simulated 

3

 A node is the point within a model cell at which head is calculated. 

groundwater system. To create backward tracking flow paths, 

the model, for each node specified, calculates a starting point 

for groundwater that ultimately ends up at the specified node. 

This allows for the calculation of the areas contributing flow 

to features of interest. For example, by specifying each node 

assigned to simulate the Lake Michigan shoreline, an area can 

be delineated that includes all flow paths that directly supply 

water to the Lake. The resulting flow paths in the calibrated 

simulation generally extend north and south from each feature, 

just as would be interpreted from the contours in figure 29, but 

additional details in flow can be seen. The area contributing 

water to Brown Ditch in the calibrated simulation is predominantly from the south, but some flow seemingly is captured 

that enters the ditch from the north. Capture zones for Brown 

and Kintzele Ditches overlap in the area southwest of their 

confluence; this is likely due to deeper flow paths discharging 

into one ditch while shallower flow paths discharge into the 

other. The majority of groundwater in the area west of Lakeshore County Road beneath Great Marsh flows into Derby 

Ditch.

In figure 31, the vertical distribution of the flow lines 

just discussed is shown at two north-south cross sections, 

one along model column 52 beneath Derby Ditch just east of 

Broadway (fig. 31A) and the other along column 197 beneath 

Brown Ditch (fig. 31B) (column locations shown in fig. 

21). Both sets of flow lines show the same pattern of mostly 

downward-directed vertical flow near groundwater divides and 

mostly horizontal flow away from the divides. 

Results from the calibrated simulation indicate that the 

majority of groundwater flowing from the south in the western 

portion of the modeled area flows into the zones that represent 

Great Marsh before entering Derby Ditch. The majority of 

groundwater flowing from the south in the eastern portion of the 

modeled area discharges to Brown Ditch. In figure 31A, flow 

from a large area to the south of US-12 and Great Marsh and in 

the western portion of the study area flows north beneath US-12 

where some of the flow enters Great Marsh, and the rest flows 

further north and discharges to Derby Ditch. A smaller amount 

of flow from the northern dune ridge flows south and discharges 

to Derby Ditch. In figure 31B, flow from a large area to the 

south of US-12 and Great Marsh and in the eastern portion of 

the study area flows beneath US-12. A small portion enters 

Great Marsh while the remaining flow continues north and 

discharges to Brown Ditch. Flow originating from the northern 

dune ridge flows south and enters Great Marsh north of Brown 

Ditch. In both figures 31A and 31B, flow from the north side of 

the northern dune ridge flows north to Lake Michigan.
Simulation of Groundwater Flow 63

Brown Ditch

Derby Ditch

Kintzele

Ditch

LAKE MICHIGAN

LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA DUNES 

STATE PARK

STATE PARK ROAD

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

North American Datum of 1983

EXPLANATION

610

Simulated water-table contour—Shows the altitude of the 

water table in feet above North American Vertical Datum 

of 1988 simulated by the groundwater-flow model in the 

surficial aquifer. Contour interval variable.

Groundwater divide—Approximate simulated divide in surficial 

aquifer, March 27−28, 2013

Arrow indicating direction of groundwater flow inferred 

from simulated water-table contours

596

614

616

618

620

600

598

592 588

584 580

610 612

604

604

606 608

610 612

602 606 608

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Figure 29. Simulated water-table contours from the modified groundwater-flow model of the Great Marsh area near Indiana 

Dunes National Lakeshore, Indiana.
64 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Brown Ditch

Derby Ditch

Kintzele

Ditch

LAKE MICHIGAN

LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA DUNES 

STATE PARK

STATE PARK ROAD

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

North American Datum of 1983

EXPLANATION

Model boundary

Horizontal groundwater-flow path within the surficial aquifer terminating in Derby Ditch.

Horizontal groundwater-flow path within the surficial aquifer terminating in Brown Ditch.

Horizontal groundwater-flow path within the surficial aquifer terminating in Kintzele Ditch.

Horizontal groundwater-flow path within the surficial aquifer terminating in Lake Michigan.

Arrow indicating general direction of groundwater flow simulated by the modified 

groundwater-flow model.

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Figure 30. Flow lines representing simulated groundwater-flow paths in the surficial aquifer under steady-state conditions, 

March 2013, near Indiana Dunes National Lakeshore, Indiana. (Arrows represent general directions of simulated groundwater flow)
Groundwater-flow path EXPLANATION

Column 197

Great Marsh

SOUTH

B. Groundwater

divide

Column 52

SOUTH

A.

Groundwater-flow path

EXPLANATION

Derby ditch 

Groundwater

divide

Brown ditch

Groundwater

divide

Great Marsh

US-12

US-12

Generalized direction of groundwater flowGeneralized direction of groundwater flow

Figure 31. Vertical flow paths simulated with the modified groundwater-flow model. A., Flow paths along column 52 and through Derby Ditch. B., Fl

197 and through Brown Ditch. (Column locations are shown in fig. 21.)
66 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Simulated Inundated Areas

Inundated areas (areas where the water table is simulated 

to be above the land surface) and areas where the water table 

is simulated to be within 7 ft of the land surface (the estimated 

altitude of typical basements or other below grade structures) are displayed in figure 32. The display of the simulated 

inundated areas helps describe the differences in the simulated 

position of the water table in relation to the land surface in the 

modeled area between the simulated March 2013 condition 

and other simulated scenarios. Inundated areas were calculated 

by using the altitude of the simulated, steady-state water table 

and the lidar-based, land-surface elevation dataset. The digital 

land-surface altitude was subtracted from the water-table 

altitude to calculate the depth of the water table above the land 

surface. At the point where the water table rises above land 

surface, surface runoff should be generated. Because of this, 

the actual area where water levels rise above ground surface 

may be smaller than the area shown in figure 32, even though 

the amount of surface runoff is estimated to be small because 

of the high permeability of the materials at land surface. 

Imprecision in land-surface altitude in some of the areas represented also adds to the uncertainty of the estimated area of 

inundation for parts of the model. 

Water levels in most areas north of Beverly Drive and 

south of US-12 are simulated to be below the land surface 

with exceptions being smaller wetland cells just west of the 

intersection of Lakeshore County Road and Beverly Drive, 

smaller interdunal wetlands north of Beverly Drive and Brown 

Ditch in the eastern portion of the modeled area, and areas 

near the upstream portions of Brown Ditch in the southeast 

portion of the study area. Ponded water is simulated extensively in the area of Great Marsh north of US-12 and south of 

Beverly Drive throughout the study area although the ponded 

area is smaller to the east of Lakeshore County Road. In the 

eastern portion of the modeled area, water levels are simulated 

to be within 7 ft of the land surface directly north of US-12 

in the area of Town of Pines and within 3 ft north of those 

areas and closer to Great Marsh. In the western portion of the 

modeled area, water levels are simulated to be within 7 ft of 

the land surface directly south of US-12, and within 3 ft of the 

land surface north of US-12. 

Sensitivity Analysis

The purpose of a sensitivity analysis is to determine 

the parameters that are more important to water levels and 

streamflow gain/loss predictions within the model (Hill and 

Tiedeman, 2007). If certain parameters substantially affect 

simulated water levels, then these parameters are important to 

accurate model predictions. The process of automated parameter estimation provides three types of sensitivity-related data: 

dimensionless scaled sensitivity, 1-percent scaled sensitivities, 

and composite scaled sensitivities (Hill, 1998, p.14–16; Hill 

and Tiedeman, 2007, p. 46–56). 

The three types of sensitivity data reflect the degree 

of change in water levels for a given change in a parameter 

value. The dimensionless scaled sensitivity numbers can be 

used to compare the importance of different observations to 

the estimation of each of the parameters, a comparison that 

is useful during calibration. One-percent scaled sensitivities 

measure the variation in sensitivity of observations to a parameter throughout the model. One-percent scaled sensitivities 

are calculated for each node of the model, and the sensitivities 

can be mapped. The areas of larger sensitivity for a parameter are good locations for obtaining additional observations 

to improve the estimate of the parameter. The CSS measure 

the sensitivity of model output to variations in a given model 

parameter on the basis of the available set of observations. 

Larger values of CSS associated with a specific parameter 

mean that the available observations are more useful in estimating those parameters. 

The CSS values for the calibrated model parameters are 

listed in table 9. A high CSS value indicates that the observations used in the model provide enough information to estimate a particular parameter, and the parameter can therefore 

be estimated by automated methods. Hydraulic conductivity 

of the surficial aquifer and of the northern dune ridge surficial 

aquifer (ks and kBevS, respectively), parameters for recharge 

rates to the aquifer for areas with undeveloped (non-wetland/

non-urban) wetland, the town of Beverly Shores, and Town of 

Pines (SandRech, MarshRech, BevShoresR, and PinesRech) 

are the major parameters controlling water-level elevations. 

All these parameters have relatively high CSS values, indicating that sufficient observations were available to estimate 

those parameters. If the major parameters are adequately 

estimated, then the simulated water-level surfaces have a 

higher probability of reflecting actual conditions. For these 

parameters, the parameter-estimation process was used to 

calculate an initial parameter that was then finalized by using 

manual techniques, including trial-and-error adjustment of the 

estimated parameter value. If the adjustment of any parameter 

achieved lower total RMSE values for both head and flow 

observations, the adjusted parameter value was assigned as the 

final value.

Significant correlations between parameters also are 

listed in table 9. The parameter representing the hydraulic 

conductivity of the ks is correlated to parameters for recharge 

rates to the aquifer for areas with undeveloped (non-wetland/

non-urban), wetland, and areas representing Beverly Shores 

and Town of Pines as well as the hydraulic conductivity of the 

wetland areas (SandRech, MarshRech, BevShoresR, PinesRech, and kwet). Although the use of parameter-estimation 

techniques are not recommended on parameters that are correlated with each other, these techniques were used on these 

parameters to assist in model calibration. Once final parameter 

values were determined, the parameter-estimation process was 

repeated with different starting values for these parameters, 

which resulted in values equal to the previously determined 

final parameter values.
87° 86°59' 86°58' 86°57

41°39'30"

41°40'30"

41°41'30" 

41°40'

41°41'

41°42'

0.5 1 

0 0.5 1 2 KILOMETERS

Base from U.S. Geological Survey digital data 1983, 1:100,000 0Universal Transverse Mercator projection, Zone 16Standard parallel 0° (Equator), Central meridian 87° WNorth American Datum of 1983

EXPLANATION

The water table is between 0 and 3 feet 

below land surface

The water table is above the land surface

The water table is greater than 7 feet 

below land surface 

The water table is between 3 and 7 feet 

below land surface 

Water-table position in the March 2013 simulation:

LAKE MICHIGAN

Brown Ditch

Derby Ditch LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12 Town of Pines

Beverly Shores

20

CENTRAL AVENUE

CAROLINA AVENUE

Figure 32. Simulated water-table position within areas near the town of Beverly Shores, Town of Pines, and within Great Marsh, Indiana Dunes Indiana, March 2013.
68 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Model Simulations of Hydrologic Modifications 

and Climatic Effects on the Brown Ditch 

Watershed

In addition to the groundwater-flow model of the March 

2013 hydraulic condition, several other scenarios were run 

with the groundwater-flow model to simulate the effects of 

various drainage modifications and climatic conditions on the 

simulated hydrology in the modeled area. These scenarios 

were simulated by using the groundwater-flow model calibrated to the March 2013 hydraulic condition because it most 

represents the current conditions of the study area. 

Simulated drainage modifications and engineering controls included the following:

1. Including a beaver dam in Brown Ditch present in April 

2014. The simulated conditions of this scenario would 

decrease amounts of flow through the ditch and increase 

water levels in the areas upstream of the beaver dam 

located on the upstream side of Central Avenue. Results 

of the simulation are compared to data collected on April 

29, 2014, while the beaver dam was present. 

2. Decreasing the discharge from Brown Ditch by simulating proposed control structures within the channel of the 

ditch. This was simulated by increasing the elevation of 

the drain cells that represent Brown Ditch, effectively 

increasing the amount of water allowed to pool behind 

proposed control structures within the channel of the 

ditch. Proposed control structures are pool-riffle type 

structures where the elevation of a spillway is a significantly higher elevation (approximately 3–4 ft) than the 

ditch upstream of the structure causing water to pool 

on the upstream side. Locations of the proposed control 

structures were estimated by INDU staff.

Two climate-related conditions were simulated: 

1. An increase in the water level of Lake Michigan, 

represented by setting the value of the northern boundary condition of the groundwater-flow model equal to 

the extreme high level of 583.86 ft NAVD 88 recorded 

on May 31, 1998, at the NOAA Lake Michigan monitoring site at Calumet Harbor, Ill. (period of record 

March 12, 1905, through September 8, 2011; National 

Oceanic and Atmospheric Administration, 2011). The 

conditions of this scenario would simulate the effects of 

higher Lake Michigan water levels on the water table 

within the study area using the March 2013 groundwater-flow model.

2. A decrease in the water level of Lake Michigan, represented by setting the value of the northern boundary 

condition of the groundwater-flow model equal to the 

extreme low level of 575.14 ft above NAVD 88 recorded 

on December 23, 2007, at the NOAA Lake Michigan 

monitoring site at Calumet Harbor, Ill. (period of record 

March 12, 1905, through September 8, 2011; National 

Oceanic and Atmospheric Administration, 2011). The 

conditions of this scenario would simulate the effects 

of lower Lake Michigan water levels on the water table 

within the study area using the March 2013 groundwater-flow model.

Results of these simulated scenarios are presented and 

compared to the results of other scenarios and the results of the 

March 2013 groundwater-flow model. Figures are presented 

that display (1) areas where the water table is simulated to be 

at or above the land surface, (2) areas where the water table 

is within 3 to 7 ft of the land surface, and (3) comparisons of 

the simulated water table from the various scenarios with the 

water table from the groundwater-flow model calibrated to the 

March 2013 hydraulic condition, or another modeled scenario. 

Simulated Inclusion of Beaver Dam to Brown 

Ditch at Central Avenue

The scenario including the Beaver Dam located at Central 

Avenue in April 2014 used the calibrated March 2013 model 

and simulated an increased extent of inundated area in Great 

Marsh and increased discharge to Brown Ditch. From May 

2012 to October 2013, NPS staff attempted to keep Brown 

Ditch clear of debris and beaver dams to assist in the collection of streamflow data at the USGS streamgage locations 

(fig. 10). Despite their best efforts and as previously discussed, the data collected at the gaging station on Brown 

Ditch at Central Avenue (USGS 04095154) were frequently 

affected by beaver dams. Following October 2013, the beaver 

dam at Central Avenue was not removed to provide data to 

estimate the effects on groundwater and surface-water levels 

of a permanent control structure at the site. Water levels in 

select wells were measured on April 29, 2014, to estimate the 

effects of the beaver dam on the water level in Great Marsh 

(fig. 17, table 5). The beaver dam remained in place until 

June 2014 when it was removed due to concerns for the stability of the Central Avenue roadbed. 

The groundwater-flow model built to simulate the March 

2013 hydraulic condition was adjusted in two ways to simulate 

the April 2014 observed conditions: 

1. Recharge parameter values were increased from the 

original values to represent increased precipitation.

2. The elevations of the bottom of the drain cells that represent Brown Ditch were adjusted to account for the location and estimated altitude of a beaver dam in the ditch 

on the upstream side of Central Avenue at the location of 

USGS streamgage 04095154 (fig. 10).
Simulation of Groundwater Flow 69

Adjustment of Parameter Values to Hydrologic Conditions

Parameters that simulate groundwater recharge in wetland 

(MarshRech), non-wetland/non-urban areas (SandRech), Beverly Shores (BevShoresR), and Town of Pines (PineRech) were 

adjusted by using a combination of parameter estimation and 

manual adjustment from the original values used in the March 

2013 simulation (table 14) in order to simulate the observed 

April 2014 conditions. The value of the parameter representing 

wetland recharge (MarshRech) increased 4.18 in/yr 

(0.35 inch per month [in/month]), from −6.91 to −2.72 in/yr. 

The value of the parameter representing recharge in non-urban 

and wetland areas (SandRech) increased 0.5 in/yr (0.04 in/

month), from 14.66 to 15.16. The parameter value representing 

recharge in Beverly Shores decreased 6.44 in/yr (0.54 in/month), 

from 21.97 to 15.53, whereas the parameter representing 

recharge in the developed areas of Town of Pines increased by 

5.07 in/yr (0.42 in/month), from 11.70 to 16.77. 

The increased recharge rates for the areas of the model 

simulating Town of Pines and non-urban and wetland areas may 

be related to above average amounts of precipitation in January 

and February 2014 (fig. 33). The decreased recharge in Beverly 

Shores may be related to increased evapotranspiration and the 

lack of artificial recharge caused by septic return flow to the 

aquifer during a relatively cold time of year, and the effects of 

using parameter-estimation techniques when no observations 

were active in the area representing Beverly Shores recharge. 

Table 14. Model parameters with the original values and the adjusted values used to match the April 2014 simulation.

[ft/d, feet per day; in/yr, inches per year; —, not applicable]

Parameter Parameter 

description

Parameter 

type

March 2013 

calibration Parameter 

derived by means 

of parameter 

estimation for 

April 2014 

simulation

April 2014 

simulation

Final 

parameter 

value

Final 

parameter 

value

kdrn1 Vertical hydraulic conductivity of the streambed 

for the ditch along US-12 

Drain 3.12 ft/d — No change

kow Hydraulic conductivity assigned to the cells of 

layer one used to simulate areas of the open 

water of East Long Lake and West Long Lake

Hydraulic conductivity10,000 ft/d — No change

ks Hydraulic conductivity of the surficial sand 

aquifer

Hydraulic conductivity17.73 ft/d — No change

kBevS Hydraulic conductivity of the surficial sand aquifer of northern dune ridgeHydraulic conductivity14.34 ft/d — No change

kwet Hydraulic conductivity of the surficial aquifer of 

Great Marsh

Hydraulic conductivity17.82 ft/d — No change

kvow Vertical hydraulic conductivity assigned to the 

cells of layer 1 used to simulate areas of the 

open water of East Long Lake and West Long 

Lake

Vertical hydraulic 

conductivity

10,000 ft/d — No change

kvs Vertical hydraulic conductivity of the surficial 

sand aquifer

Vertical hydraulic 

conductivity

5 ft/d — No change

kvBevS Vertical hydraulic conductivity of the surficial 

sand aquifer of northern dune ridge

Vertical hydraulic 

conductivity

3.0 ft/d — No change

kvwet Vertical hydraulic conductivity of the surficial 

sand aquifer of Great Marsh

Vertical hydraulic 

conductivity

10 ft/d — No change

SandRech Recharge rate to the surficial sand aquifer in nonurban and non-wetland areasRecharge 14.66 in/yr Yes 15.16 in/yr

BevShoresR Recharge rate to the surficial sand aquifer in urban 

areas

Recharge 21.97 in/yr Yes 15.53 in/yr

MarshRech Recharge rate to the surficial sand aquifer in 

wetland areas

Recharge –6.91 in/yr Yes –2.72 in/yr

PineRech Recharge rate to the surficial sand aquifer in Town 

of Pines

Recharge 11.70 ft/d Yes 16.77 ft/d

flowingWel Recharge values used to simulate flow from the 

flowing well in Beverly Shores

Recharge 533 ft/d — No change
70 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

0

5

10

15

20

Monthly precipitation, in inches

January February March

62 6162

2014

Monthly precipitation 

for Jan−May 2014

April 2014

data collection

April May

62 60

57 Number of data values in boxplot 

(above top axis) 

Outlier data value greater than 1.5 times 

the interquartile range outside the quartile 

Whisker, 90th percentile; 

10 percent of values are greater than the 

value indicated at the endpoint of the line 

75th percentile

Median

25th percentile

Whisker, 10th percentile; 

90 percent of values are greater than the 

value indicated at the endpoint of the line 

EXPLANATION

Figure 33. Box-and-whisker plots of monthly precipitation statistics for the combined records from 

the weather stations at Ogden Dunes (1951–89) and Indiana Dunes National Lakeshore, northwestern 

Indiana (1989–2013), and precipitation during January–May 2014. (Station locations are shown in fig. 1.)

To estimate the elevation of the top of the beaver dam, a 

photo was taken at the approximate level of the pooled waterlevel surface, and the elevation of the control was estimated by 

using the staff gage at the streamgage as a reference point 

(fig. 17B). The elevation value of 599.0 ft above NAVD 88 

was estimated to be ± 0.5 ft of the actual value. The beaver 

dam was simulated by adjusting the bottom elevation of drain 

cells that represent Brown Ditch to the estimated elevation of 

the top of the beaver dam. Although there is a water-surface 

slope from upstream to downstream behind the dam, it was 

assumed that the change in elevation was insignificant over the 

short distance that was affected by the dam. This adjustment 

limits the amount of water available to pool in the cell to the 

altitude of the downstream dam. Any water that would potentially pool above this altitude will flow downstream. 

Observations

The observations used for model calibration consisted 

of 19 water-level measurements made on April 29, 2014 

(table 15). Most water-level observations were in the vicinity 

of Great Marsh east of Lakeshore County Road and Town of 

Pines. The same techniques for weighting the observations 

from the calibrated March 2013 model were used for the 

April 2014 simulation.

Model Fit to Observations

The unweighted water-level residuals are shown in figure 34 

for the April 2014 simulation. The mix of positive and negative 

residuals in different parts of the model area is a characteristic of 

an adequately calibrated model. Computed statistics based on the 

unweighted water-level residuals are presented in table 16. The 

range of unweighted water-level residuals can be expressed by 

their standard deviation, which is 0.67 ft. Sixty-three percent of 

the residuals are within 1 standard deviation of the mean residual, 

and 100 percent are within 2 standard deviations. The magnitude 

of water-level residuals can be represented by the mean absolute 

error, which is 0.51 ft. The relative accuracy of the model calibration can be measured by the percent mean absolute error, which is 

the mean absolute error divided by the overall range in water levels. The percent mean absolute error for the model is 2.46 percent. 

No flow observations were made in April 2014. 

Because this is a scenario simulating a modified hydrologic 

condition based on the calibrated March 2013 model, a weighted 

residual analysis was deemed unnecessary. Unweighted residuals 

of observations collected in April 2014 were used in the adjustment of recharge parameters and to calculate statistics that are 

presented in table 16. On the basis of higher, but relatively similar 

unweighted residual statistics such as the percent mean absolute 

error (2.27 percent for March 2013, 2.46 percent for April 2014), 

the simulation adequately represents the observed conditions.
Simulation of Groundwater Flow 71

Table 15. Measured and model-calculated water levels and discharge 

measurements and modeled residuals for the April 2014 simulation. 

[NAVD 88, North American Vertical Datum of 1988]

Observation 

name Site type Date Observed value

Simulated 

value Residual

Water level, in feet above NAVD 88

MW102 Groundwater April 2014 615.10 615.41 −0.32

MW120 Groundwater April 2014 603.16 604.30 −1.14

MW104 Groundwater April 2014 610.67 609.81 0.86

C601E Surface water April 2014 604.13 604.07 0.06

MW123 Groundwater April 2014 609.03 608.45 0.58

601 Groundwater April 2014 603.28 603.28 0.00

GM-31 Groundwater April 2014 607.21 605.89 1.32

606 Groundwater April 2014 602.68 602.64 0.04

MW107 Groundwater April 2014 613.15 614.00 −0.85

MW106 Groundwater April 2014 613.22 613.29 −0.07

MW110 Groundwater April 2014 612.26 612.37 −0.11

602 Groundwater April 2014 603.39 603.21 0.18

603 Groundwater April 2014 603.44 602.96 0.48

609 Groundwater April 2014 602.92 603.79 −0.87

604 Groundwater April 2014 599.45 600.43 −0.98

610 Groundwater April 2014 605.47 605.17 0.30

GM-35 Groundwater April 2014 596.88 595.93 0.95

608 Groundwater April 2014 594.90 595.34 −0.44

607 Groundwater April 2014 594.30 594.54 −0.24
72 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Brown Ditch

Derby Ditch

Kintzele

Ditch

LAKE MICHIGAN

LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA DUNES

STATE PARK

STATE PARK ROAD

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

North American Datum of 1983

EXPLANATION

−0.34

Model boundary

1.74

Location of an observation well with a positive (blue) or negative (red) residual—

At these locations, positive values indicate the groundwater-flow model underestimated 

the water level in the observation well. Negative values indicate the groundwater-flow 

model overestimated the water level in the observation well. 

Location of a surface-water elevation monitoring site with a positive (blue) or negative (red) 

residual—At these locations, positive values indicate the groundwater-flow model 

underestimated the water level at the site. Negative values indicate the groundwater-flow 

model overestimated the water level at the site. 

−1.14

0.06

0.00

−0.32

0.18

0.04

0.48

−0.87

−0.98

1.32

0.58

0.86

−0.85

−0.11

−0.07

0.30

−0.24

−0.44

0.95

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Figure 34. Difference between observed and simulated water levels for the April 2014 simulation of the Great Marsh area 

near Indiana Dunes National Lakeshore, Indiana.
Simulation of Groundwater Flow 73

Table 16. Computed statistics based on the unweighted water-level residuals for the April 2014 hydrologic condition.

[ft, feet]

Type of 

residual

Statistics based on unweighted model residuals

Minimum 

residual 

(ft)

Mean

residual 

(ft)

Maximum 

residual 

(ft)

Standard 

deviation of 

the residuals 

(ft)

Bias

(ft)

Mean

absolute

error

Percent

mean

absolute

error

Water level −1.14 −0.01 1.32 0.67 −0.24 0.51 2.46

Simulated Water Budget

The results of the calibrated model can be quantified 

and analyzed by an overall water budget and by a budget for 

individual parts of the flow system. Table 17 lists the overall 

budget for the model simulating the conditions of April 2014. 

A large proportion of the discharge from the model 

(57 percent) goes to Brown, Kintzele, and Derby Ditches 

rather than to Lake Michigan representing an increase of 

0.58 ft3

/s over the results from the March 2013 calibrated 

model. Nearly 7 percent of the discharge from the model is 

simulated as evaporation, which is approximately 0.46 ft3/s 

less than the results from the March 2013 calibrated model. 

The water budget between the model and four areas 

of the model (fig. 28)—the Great Marsh west of Lakeshore 

County Road, Great Marsh east of Lakeshore County Road, 

Town of Pines, and Beverly Shores—for the April 2014 simulation was analyzed, and the results are shown in table 18. The 

total amount of water entering the zones representing the western and eastern portions of Great Marsh, and Town of Pines 

increased by 0.37, 0.26, and 0.35 ft3

/s, respectively. Despite 

the increases, there is still approximately zero simulated 

groundwater flow from Great Marsh to Town of Pines. The 

volume of water simulated to be entering the zone representing Beverly Shores decreased by 0.43 ft3

/s in the April 2014 

simulation. These simulated water-budget differences can be 

attributed to increased simulated recharge in Great Marsh and 

Town of Pines and decreased recharge in Beverly Shores in 

the April 2014 simulation. 

Table 17. Water budget associated with the groundwater-flow model simulating the April 2014 hydrologic condition.

[ft3/s, cubic feet per second; >, greater than]

Inflow to model

Inflow rate 

(ft3/s) and 

percent of total

Outflow from model

Outflow rate 

(ft3/s) and 

percent of total

Lake Michigan 

(constant-head boundaries)

9.40 x 10–9 0.00 Lake Michigan 

(constant-head boundaries)

1.71 36.31

Leakage into Brown Ditch,

Kintzele Ditch, and Derby 

Ditch (model drains) 

2.7 57.32

Confined aquifer 

(head-dependent boundary)

4.28 x 10–6 >1 Confined aquifer 

(head-dependent boundary)

2.70 x 10–8 >1

Precipitation (recharge) 4.71 100 Evaporation (recharge) 0.31 6.58

Total inflow 4.71 Total outflow 4.71
74 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Table 18. Water budgets for four zones of the groundwater-flow model simulating Great Marsh west of Lakeshore County Road, 

Great Marsh east of Lakeshore County Road, the town of Beverly Shores, and Town of Pines.

[ft3/s, cubic feet per second; —, not applicable]

West Great Marsh 

Zone 1

East Great Marsh 

Zone 2

Town of Pines 

Zone 3

Beverly Shores 

Zone 4

Water moving into cells 

Rate, in ft3

/s (percent of total flow)

From Recharge Zone 0 2.52 

(75.90%)

1.33 

(76.88%)

2.13 

(99.91%)

2.26 

(98.69%)

From West Great Marsh Zone 1 — 0.003 

(0.17%)

0 

(0.00%)

0.02 

(0.87%)

From East Great Marsh Zone 2 0.11 

(3.31%)

— 0.002 

(0.09%)

0.01 

(0.44%)

From Town of Pines Zone 3 0.63 

(18.98%)

0.32 

(18.50%)

— —

From Beverly Shores Zone 4 0.06

 (1.81%)

0.08 

(4.62%)

— —

Total (ft3/s) 3.32 1.73 2.13 2.29

Water moving out of cells

Rate, in ft3

/s (percent of total flow)

To Lake Michigan — — — 1.71 

(74.67%)

To ditches 1.08 

(32.53%)

0.59 

(34.10%)

0.77 

(36.15%)

0.26 

(11.35%)

To Recharge Zone 0 2.22 

(66.87%)

1.01 

(58.38%)

0.41 

(19.25%)

0.18 

(7.86%)

To West Great Marsh Zone 1 — 0.11 

(6.36%)

0.63 

(29.58%)

0.06 

(2.62%)

To East Great Marsh Zone 2 0.003 

(0.09%)

— 0.32 

(15.02%)

0.08 

(3.49%)

To Town of Pines Zone 3 0 

(0.00%)

0.002 

(0.12%)

— —

To Beverly Shores Zone 4 0.02 

(0.60%)

0.01 

(0.58%)

— —

Total (ft3/s) 3.32 1.73 2.13 2.29

Simulated Water Levels and Groundwater-Flow Paths

The results of the April 2014 groundwater-flow model 

show that the impacts from the beaver dam in Brown Ditch 

on the upstream side of Central Avenue impact water levels 

in Great Marsh. Simulated water-level contours for the April 

2014 simulation are shown in figure 35. As in the March 

2013 simulated conditions, the major groundwater divides 

are beneath the dune ridge beneath Beverly Shores and the 

dune ridge beneath Town of Pines. The major simulated flow 

paths are north from the dune ridges beneath Town of Pines 

toward Great Marsh, and Brown Ditch. To a lesser extent, 

groundwater is simulated to flow south from the dune ridge 

beneath Beverly Shores to Great Marsh and Brown Ditch. 

Another groundwater divide runs northwest-southeast from 

approximately the intersection of Beverly Drive and Lakeshore County Road and terminates near the southern boundary 

of Great Marsh; this divide has shifted slightly eastward as 

a result of the modifications to create the April 2014 model. 

Simulated changes due to the inclusion of the beaver dam 

in Brown Ditch include the shifting of the 602-, 600-, 598-, 

and 596-ft water-table contours to the east indicating that the 

water-table gradient is higher in the eastern portion of Great 

Marsh between the minor northwest-southeast trending minor 

water-table divide and Central Avenue than the condition 

simulated by the modified model (fig. 29).
Simulation of Groundwater Flow 75

Brown Ditch

Derby Ditch

Kintzele

Ditch

LAKE MICHIGAN

LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA DUNES

STATE PARK

STATE PARK ROAD

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

North American Datum of 1983

EXPLANATION

610 Simulated water-table contour—Shows the altitude of the water 

table in feet above North American Vertical Datum of 1988 

simulated by the groundwater-flow model in the surficial aquifer. 

Contour interval variable.

Groundwater divide—Approximate simulated divide in surficial aquifer, 

April 29, 2014

Arrow indicating direction of groundwater flow inferred from 

simulated water-table contours

604

606 608

610 612

602

596

614

616

618

620

600

598

592 588

584 580

610

606

612

608

596

614

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Figure 35. Simulated water-table contours from the April 2014 simulation. (Compare to fig. 29.)
76 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Backward tracking flow paths were generated for the 

April 2014 simulation in nodes representing the Lake Michigan shoreline, Derby Ditch, Kintzele Ditch, and the segment 

of Brown Ditch north of US-20 using MODPATH (Pollock, 

2012); results are shown in figure 36. Flow paths were similar 

to those for the March 2013 simulation, extending north and 

south from the groundwater divides to Lake Michigan and the 

ditches. The inclusion of the beaver dam in Brown Ditch on 

the upstream side of Central Avenue has altered the groundwater-flow paths in the eastern portion of Great Marsh from those 

presented for the March 2013 simulation (fig. 30). Longer flow 

paths now travel beneath Brown Ditch from areas just west 

of the mouth of Brown Ditch into Great Marsh and terminate 

near the confluence of Brown and Kintzele Ditches. Longer 

flow paths now travel from upstream portions of Brown Ditch 

and terminate into Kintzele Ditch. The distributions of flow 

paths flowing to Lake Michigan and Derby Ditch do not deviate from those presented for the March 2013 simulation. 

Simulated Inundated Areas

Areas where the water table is simulated to be at or above 

the land surface are displayed in figure 37. Inundated areas 

were calculated by using the altitude of the simulated, steadystate water table in April 2014 and the lidar-based land-surface 

elevation dataset. The digital land-surface altitude was subtracted from the water-table altitude to calculate the depth of 

the water table above the land surface. At the point where the 

water table rises above ground surface, surface runoff should 

be generated. Because of this, the actual area where water 

levels rise above land surface may be smaller than shown in 

figure 37, even though the amount of surface runoff is estimated to be small because of the high permeability of the 

materials at land surface. Imprecision in land-surface altitude 

in some of the areas represented also adds to the uncertainty of 

the estimated area of inundation for parts of the model. 

The distribution of inundated areas shown in figure 37 

(compare with fig. 32) displays the effects of the inclusion of 

the beaver dam in Brown Ditch just upstream of Central Avenue into the groundwater-flow model. The water table in most 

areas of Beverly Shores north of Great Marsh is simulated 

to be below the land surface except for some small locations 

north of Beverly Drive and east of Lakeshore County Road, 

which is consistent with areas estimated in the March 2013 

simulation. Likewise, areas to the south of Great Marsh in and 

around Town of Pines are simulated to be below land surface 

except for some small areas near the southern boundary of the 

active model area near the upstream reaches of Brown Ditch. 

Areas estimated to have water above the land surface increase 

in size in Great Marsh east of Lakeshore County Road and 

south of Beverly Drive, which is likely due to the effects of 

including the beaver dam in Brown Ditch just upstream of 

Central Avenue within the simulation. The total area where the 

water table is above the land surface is much greater than the 

area from the March 2013 simulation.

Simulated Inclusion of Pool-Riffle Control 

Structures in Brown Ditch

A simulated scenario with the March 2013 model in which 

six control structures were simulated resulted in enlarged areas 

simulated to be inundated by water in the March 2013 model. 

Great Marsh within the study area was historically described as 

covering an area of approximately 1,053 acres from Lakeshore 

County Road to its eastern terminus in Michigan City (Dan Mason, 

Indiana Dunes National Lakeshore, written commun., 2014). The 

NPS wishes to restore portions of Great Marsh within the study 

area by building pool-riffle type control structures within Brown 

and Kintzele Ditches, which will elevate the channel of the ditch to 

an altitude below which water will pool and saturate Great Marsh. 

In order to simulate the effects of these control structures, the calibrated March 2013 groundwater-flow simulation was modified by 

increasing the altitude of the bottom of Brown Ditch at locations 

were the NPS estimated the practice would be most beneficial. 

Overall, six control structures were included in the model, and 

their approximate locations and simulated control altitudes are 

presented in figure 38. 

The control structures were simulated by increasing the altitude 

of the drain cells simulating the bottom of Brown Ditch within the 

model at the locations specified by the NPS. Increasing the control 

altitude for the drain cells simulates pooling of the surface water on 

the upstream side of the control. No other model parameters were 

altered from the March 2013 model during this simulation.

The inclusion of the six control structures enlarged areas 

simulated to be inundated by water in comparison to the March 

2013 model, including areas just to the north of the entrance of 

Brown Ditch into Great Marsh, and areas north of the confluence 

of Brown and Kintzele Ditches (fig. 38; fig. 39, compare with 

fig. 32). There are no visible differences in the distribution of 

inundated area between the March 2013 simulation and the simulation that includes the six control structures in areas of Great Marsh 

directly northwest of the entrance of Brown Ditch into Great 

Marsh, areas west of Lakeshore County Road, or areas of Town of 

Pines south of Great Marsh. 

The budget between the model and four areas of the model 

(fig. 28)—Great Marsh west of Lakeshore County Road, Great 

Marsh east of Lakeshore County Road, Town of Pines, and Beverly Shores—for the March 2013 simulation that includes the six 

control structures in Brown Ditch was analyzed, and the results 

are shown in table 19. The total amount of water leaving the zones 

representing the eastern portions of Great Marsh, and Beverly 

Shores increased by 0.01 and 0.05 ft3

/s, respectively. These slight 

increases are most likely explained by the small increase in the 

amount of water discharging to ditches from both zones as well as 

by the increase in water leaving the model by evapotranspiration 

(recharge). The simulation did not produce or increase simulated 

discharge from Great Marsh to Beverly Shores or Town of Pines.

Groundwater- and surface-water monitoring sites simulated to 

have higher water levels in the March 2013 simulation that includes 

the six control structures in Brown Ditch than in the regular March 

2013 simulation are shown in figure 40. Increases in water level range 

from 0.03 ft in monitoring well 602 to 2.39 ft in monitoring well 608.
Simulation of Groundwater Flow 77

Brown Ditch

Derby Ditch

Kintzele

Ditch

LAKE MICHIGAN

LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

12

12

20

20

INDIANA DUNES

STATE PARK

STATE PARK ROAD

GREAT MARSH

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

North American Datum of 1983

EXPLANATION

Model boundary

Horizontal groundwater-flow path within the surficial aquifer terminating in Derby Ditch.

Horizontal groundwater-flow path within the surficial aquifer terminating in Brown Ditch.

Horizontal groundwater-flow path within the surficial aquifer terminating in Kintzele Ditch.

Horizontal groundwater-flow path within the surficial aquifer terminating in Lake Michigan.

Arrow indicating general direction of groundwater flow simulated by the modified 

groundwater-flow model.

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Figure 36. Flow lines representing simulated groundwater-flow paths in the surficial aquifer under the steady-state hydraulic 

conditions of April 2014. (Arrows represent general directions of simulated groundwater flow.)
87° 86° 59' 86°58' 86°57

41°39'30" 41°40'30" 41° 41' 30" 

41°40' 41°41' 41°42' 0.5 1 

0 0.5 1 2 KILOMETERS Base from U.S. Geological Survey digital data 1983, 1:100,000 0 Universal Transverse Mercator projection, Zone 16 Standard parallel 0° (Equator), Central meridian 87° W North American Datum of 1983 EXPLANATION The water table is between 0 and 3 feet below land surface The water table is above the land surface The water table is greater than 7 feet below land surface The water table is between 3 and 7 feet below land surface Water-table position in the April 2013 simulation: LAKE MICHIGAN Brown Ditch 

Derby Ditch LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

Beverly Shores

20

CENTRAL AVENUE

CAROLINA AVENUE

Town of Pines

Figure 37. Simulated water-table position within areas near the town of Beverly Shores, Town of Pines, and within Great Marsh, Indiana Dunes NIndiana, April 2014. (Compare with fig. 32.)
87° 86°59' 86°58' 86°57

41°39'30"41°40'30"

41°41'30" 

41°40'41°41'

41°42'

0.5 1 

0 0.5 1 2 KILOMETERS

Base from U.S. Geological Survey digital data 1983, 1:100,000 0Universal Transverse Mercator projection, Zone 16Standard parallel 0° (Equator), Central meridian 87° WNorth American Datum of 1983

Increase in water-table position in the March 2013 scenario that includes six control 

structures in Brown Ditch from the position in the March 2013 simulation:

602 Location and elevation of proposed control structure

EXPLANATION

0.5−1.0 feet 1.0−2.0 feet Greater than 2.0 feet 

LAKE MICHIGAN

Brown Ditch

Derby Ditch LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

Beverly Shores

20

CENTRAL AVENUE

E

Town of Pines

605

602

600 

Figure 38. Approximate location of six simulated control structures and their simulated altitude in Brown Ditch, the difference in water-table posMarch 2013 simulation results, and a model scenario simulating the inclusion of six control structures in Brown Ditch during the March 2013 hydrnear the town of Beverly Shores, Town of Pines, and within Great Marsh, Indiana Dunes National Lakeshore, Indiana.
87° 86°59' 86°58' 86°5

41°39'30" 41°40'30" 41°41'30" 

41°40' 41°41' 41°42' 0.5 1 

0 0.5 1 2 KILOMETERS Base from U.S. Geological Survey digital data 1983, 1:100,000 0 Universal Transverse Mercator projection, Zone 16 Standard parallel 0° (Equator), Central meridian 87° W North American Datum of 1983 Water-table position in the March 2013 simulation including six control structures in Brown Ditch: EXPLANATION The water table is between 0 and 3 feet below land surface The water table is above the land surface The water table is greater than 7 feet below land surface The water table is between 3 and 7 feet below land surface LAKE MICHIGAN Brown Ditch 

Derby Ditch LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

Beverly Shores

20

CENTRAL AVENUE

Town of Pines

Figure 39. Water-table position resulting from a model scenario simulating the inclusion of six control structures in Brown Ditch during the Marcondition near the town of Beverly Shores, Town of Pines, and within Great Marsh, Indiana Dunes National Lakeshore, Indiana. (Compare with fi
Simulation of Groundwater Flow 81

Table 19. Water budgets of four zones of the groundwater-flow model simulating Great Marsh west of Lakeshore County Road, 

Great Marsh east of Lakeshore County Road, the town of Beverly Shores, and Town of Pines using the simulation that includes six 

control structures in Brown Ditch.

[ft3/s, cubic feet per second; —, not applicable]

West Great Marsh 

Zone 1

East Great Marsh 

Zone 2

Town of Pines 

Zone 3

Beverly Shores 

Zone 4

Water moving into cells 

Rate, in ft3

/s (percent of total flow)

From Recharge Zone 0 2.194 

(74.37%)

1.11 

(75.00%)

1.78 

(100.00%)

2.74 

(98.92%)

From West Great Marsh Zone 1 — 0.005 

(0.34%)

0.00 

(0.00%)

0.02 

(0.72%)

From East Great Marsh Zone 2 0.1 

(3.39%)

— 0.002 

(0.11%)

0.008 

(0.29%)

From Town of Pines Zone 3 0.58 

(19.66%)

0.26 

(17.57%)

— —

From Beverly Shores Zone 4 0.084 

(2.85%)

0.1 

(6.76%)

— —

Total (ft3/s) 2.95 1.48 1.78 2.77

Water moving out of cells

Rate, in ft3

/s (percent of total flow

To Lake Michigan — — — 1.95

 (70.40%)

To ditches 0.83 

(28.14%)

0.32 

(21.62%)

0.6 

(33.71%)

0.37 

(13.36%)

To Recharge Zone 0 2.1 

(71.19%)

1.05 

(70.95%)

0.34 

(19.10%)

0.28 

(10.11%)

To West Great Marsh Zone 1 — 0.1 

(6.76%)

0.58 

(32.58%)

0.08 

(2.89%)

To East Great Marsh Zone 2 0.005 

(0.17%)

— 0.26 

(14.61%)

0.1 

(3.61%)

To Town of Pines Zone 3 0.00 

(0.00%)

0.02 

(0.68%)

— —

To Beverly Shores Zone 4 0.02 

(0.68%)

0.008 

(0.54%)

— —

Total (ft3/s) 2.95 1.48 1.78 2.77
82 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Brown Ditch

Derby Ditch

Kintzele

Ditch LAKE MICHIGAN

Beverly Shores

LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

Town of Pines

Michigan City

20

12

12

12

20

20

INDIANA DUNES

STATE PARK

STATE PARK ROAD

0.38

0.31

CENTRAL

AVE.

0.03

0.13

0.10

0.80 0.83

2.39

1.80

0.23

0.15

0.05 0.04

1.34

1.09

1.31

0.59

0.5 1 2 MILES

0 0.5 1 KILOMETERS

0

2

Base from U.S. Geological Survey digital data 1983, 1:100,000

Universal Transverse Mercator projection, Zone 16

Standard parallel 0° (Equator), Central meridian 87° W

North American Datum of 1983

EXPLANATION

Indiana Dunes National Lakeshore (INDU) 

Model boundary

0.13 Location of an observation well with a water level in the simulation 

including six pool-riffle control structures greater than the simulation 

of the March 2013 hydrologic condition.

1.34 Location of a surface-water-level monitoring site with a water level in the 

simulation including six pool-riffle control structures greater than the 

simulation of the March 2013 hydrologic condition.

41° 39' 30"

41° 40' 30"

41° 41' 30"

41° 42' 30"

41° 40'

41° 41'

41° 42'

87° 01' 87° 86° 59' 86° 58' 86° 57' 86° 56' 86° 55'

Figure 40. Increases in water level at groundwater-monitoring wells and surface-water monitoring sites in the March 2013 

simulation, which includes six control structures in Brown Ditch. 
Simulation of Groundwater Flow 83

Conceptually, the inclusion of control structures within Brown 

Ditch increases the likelihood of water flowing from the ditch to the 

surrounding aquifer due to possibly higher water levels upstream of 

the control structures within the ditch than in the surrounding aquifer. Because the results of the March 2013 simulation that included 

six control structures in Brown Ditch did not produce results showing the expected increase in the water table in the area northwest of 

the point where Brown Ditch flows into Great Marsh near Beverly 

Drive, the conceptual model was reevaluated and simulations that 

use the MODFLOW River package (Harbaugh and others, 2000) to 

simulate the segment of Brown Ditch from its entrance into Great 

Marsh to its termination where it flows into Kintzele Ditch were 

completed. The MODFLOW River package differs from the Drain 

package used in the previous simulations by including the ability of 

the simulated river cells to contribute water back to the surrounding cells that simulate the aquifer when water levels in the ditch 

are simulated to be higher than those simulated in the surrounding 

aquifer. 

The use of the MODFLOW River package in simulating 

Brown Ditch within Great Marsh produced larger areas simulated 

to be inundated by water in comparison to the March 2013 model 

that includes six control structures in Brown Ditch including areas 

just to the south of Beverly Drive and east of Lakeshore County 

Road and areas on either side of Carolina Avenue north of Brown 

Ditch (fig. 41; fig. 42, compare with fig. 38 and fig. 39). There are 

small increases in the distribution of inundated area south of Brown 

Ditch and north of US-12. The distribution of inundated areas of 

the simulations using the MODFLOW River package to simulate 

Brown Ditch within Great Marsh better represent the observed distribution during periods when the surficial aquifer is most saturated 

due to high precipitation or snowmelt. 

Simulated Increase in Level of Lake Michigan

A scenario simulating the increase in the level of Lake 

Michigan was run with the calibrated March 2013 model to 

estimate the effects of increasing the water level of the major 

discharge point of the surficial aquifer and surface-water 

drainages on simulated hydrology in the modeled area. In 

order to perform the simulation, the constant-head boundary 

condition that represents Lake Michigan along the northern 

part of the model (fig. 23) was set equal to the extreme high 

level of 583.86 ft above NAVD 88 recorded on May 31, 1998, 

at the NOAA Lake Michigan monitoring site at Calumet Harbor, Ill. (period of record March 12, 1905, through September 

8, 2011), an increase of 6.99 ft. No other parameter values or 

model input values were changed from those presented earlier 

in the report.

The simulated result of increasing the level of Lake 

Michigan was an increased area of inundated land relative to 

the March 2013 area (fig. 43; compare with fig. 32). Inundated areas of Great Marsh south of Beverly Shores enlarged 

on both sides of Lakeshore County Road with the greatest 

enlargement shown southeast of the intersection of Lakeshore 

County Road and Beverly Drive. In Beverly Shores, larger 

areas are simulated to be within 7 ft of the land surface likely 

in low lying interdunal areas. No significant changes in inundated area or areas of groundwater flooding resulted from the 

simulation in the area of Town of Pines.

Simulated Decrease in Level of Lake Michigan

A scenario simulating the decrease in the level of Lake 

Michigan was run on the calibrated March 2013 model to 

estimate the effects on simulated hydrology in the modeled 

area. In order to perform the simulation, the constant-head 

boundary condition that represents Lake Michigan along 

the northern part of the model (fig. 23) was set equal to the 

extreme low level of 575.14 ft above NAVD 88 recorded on 

December 23, 2007, at the NOAA Lake Michigan monitoring 

site at Calumet Harbor, Ill. (period of record March 12, 1905, 

through September 8, 2011), a decrease of 1.73 ft. No other 

parameter values or model input values were changed from 

those presented earlier in the report.

The decrease of the level of Lake Michigan had little 

effect on the size of the area where the water table is simulated to be above land surface or the area where the water 

table reaches within 7 ft of the land surface (fig. 44; compare 

with fig. 32). The lack of changes in the study area can most 

likely be explained by the small difference between the value 

of Lake Michigan simulated in the March 2013 model and the 

extreme low value used in this simulation.
87° 86° 59' 86° 58' 86° 57

41° 39' 30"41° 40' 30"

41° 41' 30" 

41° 40'41° 41'

41° 42'

0.5 1 

0 0.5 1 2 KILOMETERS

Base from U.S. Geological Survey digital data 1983, 1:100,000 0Universal Transverse Mercator projection, Zone 16Standard parallel 0° (Equator), Central meridian 87° WNorth American Datum of 1983

Segment of Brown Ditch simulated using MODFLOW River cells instead of Drain cells

Increase in water-table position in the March 2013 scenario that uses River cells instead of Drain cells 

and includes six control structures in Brown Ditch:

602 Location and elevation of proposed control structure

EXPLANATION

0.5−1.0 feet 1.0−2.0 feet 2.0−3.0 feet Greater than 3.0 feet 

LAKE MICHIGAN

Brown Ditch

DerbyDitch LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12 The Pines

Beverly Shores

20

CENTRAL AVENUE 602

OLINA AVENUE 600 

605

Figure 41. Approximate location of six simulated control structures and their simulated altitude in Brown Ditch, the difference in water-table posMarch 2013 simulation results, and a model scenario simulating the inclusion of six control structures in Brown Ditch during the March 2013 hydrusing MODFLOW River package to simulate Brown Ditch within Great Marsh near the town of Beverly Shores, Town of Pines, and within Great MNational Lakeshore, Indiana. (Compare with fig. 38.)
87° 86° 59' 86° 58' 86° 57

41° 39' 30"41° 40' 30"

41° 41' 30" 

41° 40'41° 41'

41° 42'

Segment of Brown Ditch simulated using MODFLOW River cells instead of Drain cells

Increase in water-table position in the March 2013 scenario that uses River cells instead of Drain cells and includes six

 control structures in Brown Ditch:

602 Location and elevation of proposed control structure

EXPLANATION

Locations where the water table is above the 

land surface in the March 2013 simulation

Additional locations where the water table is above the land 

surface with the inclusion of six control structures

0.5 1 

0 0.5 1 2 KILOMETERS

Base from U.S. Geological Survey digital data 1983, 1:100,000 0Universal Transverse Mercator projection, Zone 16Standard parallel 0° (Equator), Central meridian 87° WNorth American Datum of 1983

LAKE MICHIGAN

Brown Ditch

DerbyDitch LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12 The Pines

Beverly Shores

20

CENTRAL AVENUE 602

CAROLINA AVENUE 600 

605

Figure 42. Inundated land surface areas resulting from a model scenario simulating the inclusion of six control structures in Brown Ditch during hydrologic condition using MODFLOW River package to simulate Brown Ditch within Great Marsh near the town of Beverly Shores, Town of PinesMarsh, Indiana Dunes National Lakeshore, Indiana. (Compare with fig. 39.)
87° 86°59' 86°58' 86°57

41°39'30" 41°40'30" 41°41'30" 

41°40' 41°41' 41°42' 0.5 1 

0 0.5 1 2 KILOMETERS Base from U.S. Geological Survey digital data 1983, 1:100,000 0 Universal Transverse Mercator projection, Zone 16 Standard parallel 0° (Equator), Central meridian 87° W North American Datum of 1983 Water-table position in the March 2013 simulation with Lake Michigan at extreme high level: EXPLANATION The water table is between 0 and 3 feet below land surface The water table is above the land surface The water table is greater than 7 feet below land surface The water table is between 3 and 7 feet below land surface LAKE MICHIGAN Brown Ditch 

Derby Ditch LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

Beverly Shores

20

CENTRAL AVENUE

CAROLINA AVENUE

Town of Pines

Figure 43. Water-table position resulting from a model scenario simulating the water level of Lake Michigan at extreme high level and March 20town of Beverly Shores, Town of Pines, and within Great Marsh, Indiana Dunes National Lakeshore, Indiana. (Compare with fig. 32.)
87° 86°59' 86°58' 86°57

41°39'30"41°40'30"

41°41'30" 

41°40'41°41'

41°42'

0.5 1 

0 0.5 1 2 KILOMETERS

Base from U.S. Geological Survey digital data 1983, 1:100,000 0Universal Transverse Mercator projection, Zone 16Standard parallel 0° (Equator), Central meridian 87° WNorth American Datum of 1983

Water-table position in the March 2013 simulation with Lake Michigan at extreme low level:

EXPLANATION

The water table is between 0 and 3 feet 

below land surface

The water table is above the land surface

The water table is greater than 7 feet 

below land surface 

The water table is between 3 and 7 feet 

below land surface 

LAKE MICHIGAN

Brown Ditch

DerbyDitch LAKESHORE COUNTY ROAD

BROADWAY

BEVERLY DRIVE

20

12

Beverly Shores

20

CENTRAL AVENUE

CAROLINA AVENUE

Town of Pines

Figure 44. Water-table position resulting from a model scenario simulating the water level of Lake Michigan at extreme low level and March 201town of Beverly Shores, Town of Pines, and within Great Marsh, Indiana Dunes National Lakeshore, Indiana. (Compare with fig. 32.)
88 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Model Limitations and Qualifications

Predictive simulations by the groundwater model should 

be evaluated and qualified on the basis of model reliability 

(Anderson and Woessner, 1992, p. 284). The reliability of the 

calibration is dependent upon the assumptions used in construction of the model and the adequacy (abundance, distribution, and accuracy) of the observations used in the calibration. 

The simplifying assumptions used in the development of this 

model were previously discussed. Although these assumptions 

were in some ways tested and described within this report, 

more data may be required to fully evaluate these and other 

assumptions. The following factors should be considered when 

evaluating this model and any predictive simulations that this 

model may produce: 

1. The model presented in this report is a modification of a 

previously published model and was constrained to the 

extent of the original model. Testing of the sensitivity of 

the results of the simulation to the boundary conditions 

of the model resulted in the alteration of water levels 

throughout the study area and, in the vicinity of Brown 

Ditch, Great Marsh, and the residential area along US-12 

east of Lakeshore County Road, changes of approximately ± 1 ft. 

2. In order to simulate ponding of water on the land 

surface, the model was constructed with model layer 

1 representing open water with horizontal and vertical 

hydraulic conductivity values of 10,000 ft/d. The accuracy of simulating volumes of open water in a model 

is directly related to the ability of using large values of 

hydraulic conductivity. The numerical solution of this 

groundwater-flow model became unstable with values 

greater than 10,000 ft/d. Although this value does not 

represent the ability of water to move without resistance, 

it is an adequate representation for this simulation. At 

the point where the water table rises above land surface, 

surface runoff should be generated. Because of this, the 

actual area where water levels rise above ground surface 

may be smaller than the area shown in the figures even 

though the amount of surface runoff is estimated to be 

small, owing to the high permeability of the materials at 

land surface.

3. Figures displaying inundated areas were calculated by 

using the altitude of the simulated, steady-state water 

table and lidar-based land-surface elevation contour 

datasets with an interval of 1 ft. Lidar-based elevations 

are accurate in areas of no ponded water. The dataset 

includes information on areas where ponded water was 

encountered. The displayed area of inundation could be 

less accurate in these areas. Uncertainty of the displayed 

area of inundation is made up of both the overall fit of 

the groundwater-flow model, errors associated with the 

discretization of the model areas into cells, and inaccuracies of the lidar-based land-surface altitudes. 

4. The model is best used to simulate groundwater flow in 

the surficial aquifer surrounding Great Marsh because 

almost all of the observations used to calibrate the model 

are from the surficial sand aquifer simulated by layer 

2. Fewer observations were used to calibrate the April 

2014 simulation and almost all of those were east of 

Lakeshore County Road to simulate interactions between 

Great Marsh and Town of Pines due to the observed 

beaver dam. The simulated water-table configuration 

and groundwater-flow paths are considered to be more 

accurate near the areas surrounding Great Marsh than in 

areas with fewer observations. 

5. Direct measures of recharge rates to the simulated 

deposits were not possible. Initial estimates of recharge 

were taken from investigations in similar areas with 

a similar makeup of materials. Automated parameter 

estimation and manual calibration techniques were used 

to derive final values for recharge for the groundwaterflow model.

6. The model was constructed by use of two layers to 

represent the surficial aquifer in the modeled area. Initial 

efforts were made to include additional model layers 

that would simulate the finer grained muck deposits 

in wetland areas and a leaky confining unit that may 

underlie parts of the modeled area. Investigations in 

similar areas have attempted to use model parameters 

to represent similar features but the model results were 

found to be insensitive to whether the features were or 

were not included during the model calibration process 

(Lampe and Bayless, 2013). Inclusion of these features 

was therefore not attempted by this investigation. 

Comparison of Results to Previous 

Investigations

The ability of Great Marsh to retain wetland conditions 

during relatively dry portions of the year is associated with the 

area being bounded by the Holocene and Calumet Dune Beach 

Complexes, each having water-table mounds that contribute 

recharge to the surficial aquifer. The configuration is similar to those of Shedlock and others (1994) in which areas of 

recharge were mapped in areas beneath the Holocene Dune 

Beach Complex and groundwater was interpreted to flow 

south from these areas to Great Marsh and other interdunal 

wetlands and north to Lake Michigan. 

The water-table configuration differs from water-table 

configurations found by Lampe and Bayless (2013) in a similar investigation of a study area approximately 13 mi west. 

Significant differences were observed due to the absence of 

the northern Holocene dune ridge, which was removed by 

sand-mining operations. In that study, areas of recharge were 

simulated to occur beneath the Toleston Dune Beach Complex 

with groundwater-flow paths extending north through low 

lying areas and water-level altitudes diminishing onward to 
Summary and Conclusions 89

Lake Michigan producing a transient wetland condition in the 

area between. 

Winter (1999) proposes that the integrated knowledge of 

regional position within the groundwater-flow system and an 

understanding of the local geology and climate are necessary 

to understand areas of groundwater/surface-water interaction, 

and Doss (1993) illustrates the importance of considering 

the transient nature of interdunal wetlands by presenting the 

migration of groundwater divides due to not only topography, but also evapotranspiration, soil moisture, and recent 

recharge. Data collected during this study may show the 

effects of transient change in the water table along the margins 

of interdunal wetlands and the reversal of groundwater flow 

from Great Marsh during periods of relatively dry conditions. 

Future studies could focus on simulating transient conditions 

to help determine the impacts of prolonged dry conditions on 

the overall impacts of these different water cycle components 

on interdunal wetland environments like Great Marsh within 

INDU.

Summary and Conclusions

A previously published steady-state groundwater-flow 

model by Shedlock and Harkness (1984) was reconstructed 

using MODFLOW-NWT. The results of the reconstructed 

model were verified by comparing the output to the figures 

published in the original report. Following model verification, the reconstructed model was modified to more accurately simulate the conditions of the study area. The modified 

groundwater-flow model—a steady-state, three-layer computer 

model consisting of 105 rows, 225 columns, and 3 layers—was 

calibrated to an observed hydrologic condition (March 2013) to 

simulate flow through the surficial aquifer and the interaction 

between hydrologic features in and around Great Marsh in the 

Indiana Dunes National Lakeshore near Beverly Shores and 

Town of Pines, Indiana. The top layer simulated water bodies by 

using a high hydraulic conductivity of 10,000 feet per day (ft/d), 

and the remaining two layers simulated the majority of the 

surficial aquifer.

Small observed differences between the water-level 

data collected during the March 2013 and the April 2014 

hydraulic conditions include the pooling of surface water due 

to the effects of a beaver dam present in Brown Ditch just 

upstream of Central Avenue. Continuous groundwater-level 

data collected during May 2012–December 2013 indicate that 

the predominant groundwater-flow gradients vary during the 

course of the year (fig. 16). The comparison of annual growing 

season to the land-surface elevation at 12 site-specific monitoring wells indicates the presence and duration of a wetland 

condition in different areas of Great Marsh (appendix 1). At 

the beginning of the study in May of 2012, data collected at 

eight well sites were indicative of a wetland condition, but 

levels decreased by July 2012 due to increased transpiration 

from vegetation and lack of prolonged significant precipitation 

in the area during the months of April, May, and June (figs. 11 

and 12). In contrast, data collected from one monitoring well 

(observation well 605) indicated the site maintained wetland 

condition throughout the 2012 growing season.

Continuous surface-water discharge and elevation was 

measured at one U.S. Geological Survey (USGS) streamgage 

location on Brown, Kintzele, and Derby Ditches (fig. 10). The 

mean monthly discharge statistics (table 7) indicate that during 

the period of record, streamflow in Kintzele Ditch was lowest 

during July 2012 (0.97 cubic foot per second [ft3

/s]) and highest during April 2013 (29.20 ft3

/s). In Derby Ditch, streamflow 

also was lowest during July 2012 (0.17 ft3/s) and highest during April 2013 (9.36 ft3

/s). Continuous discharge could not be 

calculated from data collected at USGS streamgage 04095154 

on Brown Ditch due to the repeated construction and removal 

of beaver dams at the gage site, which created continuously 

changing control and backwater conditions.

Nonlinear least-squares regression was used with automated parameter estimation to determine optimum parameter values for the model. The calibrated value of hydraulic 

conductivity for the sand was 17.73 ft/d, and recharge rates for 

the March 2013 model calibration varied from −6.91 inches 

per year (in/yr) for wetland areas representing evaporation to 

21.97 in/yr for recharge in populated areas of Beverly Shores. 

The mean absolute error between simulated and measured 

water levels is 0.81 foot (ft), which translates into a relative 

error (based on water-level variation in the measured water 

levels) of 2.27 percent.

Noteworthy results from the March 2013 simulation 

include that nearly 100 percent of all water entering the area 

simulating Town of Pines is from recharge. Of all the water 

simulated to enter the eastern and western portions of Great 

Marsh, nearly 20 and 18 percent, respectively, flows from 

Town of Pines to the western and eastern portions of Great 

Marsh. The dune ridges beneath Town of Pines and to a lesser 

extent beneath Beverly Shores are a major source of recharge 

to the surficial aquifer and Great Marsh. 

Particle tracking results from the March 2013 simulation 

indicate the area contributing water to Brown Ditch is predominantly to the south, but some flow is captured that enters 

the ditch from the north (fig. 30). Capture zones for Brown 

and Kintzele Ditches overlap in the area south-west of their 

confluence; this is likely due to deeper flow paths discharging into one ditch while shallower flow paths discharge into 

the other. The majority of the area west of Lakeshore County 

Road beneath Great Marsh flows into Derby Ditch.

An additional simulation was created by adjusting the 

calibrated March 2013 model to match surface-water and 

groundwater levels measured during April 2014 when a beaver 

dam in Brown Ditch altered the hydrologic conditions of the 

study area. Adjustments were made by (1) increasing recharge 

parameters from the calibration values to compensate for the 

increased amount of precipitation prior to data collection, 

and (2) manipulating the elevation of the bottom of the drain 

cells that represent Brown Ditch to account for the location 

and relative altitude of the beaver dams observed during data 
90 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

collection. The recharge values representing Town of Pines, 

wetland, and undeveloped areas of the model were increased 

by 5.07, 4.182, and 0.5 in/yr, respectively. The recharge value 

for the area representing Beverly Shores was decreased by 

6.44 in/yr. 

Noteworthy results from the April 2014 simulation 

include that despite increases in the amount of water entering 

Great Marsh, there is still zero simulated groundwater flow 

from Great Marsh to Town of Pines. This simulated difference in water budgets can be attributed to increased simulated 

recharge in Great Marsh and Town of Pines. Effects of the 

inclusion of the beaver dam included the enlargement of the 

simulated inundated area and the rising of the water table 

within Great Marsh due to the effects of ponding surface water 

upstream of the beaver dam (fig. 34). 

Particle tracking results from the April 2014 simulation 

indicate changes in the area contributing water to Brown and 

Kintzele Ditches (fig. 36). Compared to the 2013 simulation, the April 2014 simulation produced longer flow paths 

now travel beneath Brown Ditch from areas just west of the 

entrance of Brown Ditch into Great Marsh and terminate 

near the confluence of Brown and Kintzele Ditches and from 

upstream portions of Brown Ditch that terminate into Kintzele 

Ditch.

The distribution of inundated areas in the April 2014 

simulation show areas in Great Marsh east of Lakeshore 

County Road and south of Beverly Drive where areas estimated to have water above the land surface have increased 

in size (fig. 37). The total area where the water table is above 

the land surface is much greater than the area from the March 

2013 simulation.

Three different scenarios were run in order to apply 

certain climatic conditions and engineering controls to the 

calibrated groundwater-flow model. The results of these scenarios will give the National Park Service, and other resource 

managers in the area an improved understanding of the hydrology in the vicinity of Great Marsh in order to understand the 

effects drainage alterations will make to the water levels of the 

water table in the surrounding residential areas. 

Noteworthy results from the scenarios include the following:

1. In the scenario simulating the inclusion of six proposed 

pool-riffle control structures in Brown Ditch under the 

hydrologic conditions of March 2013, areas simulated to 

be inundated by water in the March 2013 model are much 

larger, including areas just to the north of the entrance 

of Brown Ditch into Great Marsh, and areas north of the 

confluence of Brown and Kintzele Ditches (fig. 38, fig. 

39). Results of an additional simulation using the MODFLOW River package to characterize Brown Ditch within 

Great Marsh showed areas inundated by water were larger 

than those from the simulation using the MODFLOW 

Drain package only. The additional simulation better represented the observed distribution of open water during 

periods when the surficial aquifer is most saturated due to 

high precipitation or snowmelt (fig. 41, fig. 42).

2. For the scenario simulating the increase of the Lake 

Michigan water level to the historical high of May 31, 

1998, inundated areas of Great Marsh south of Beverly 

Shores enlarged on both sides of Lakeshore County Road 

with the greatest enlargement shown southeast of the 

intersection of Lakeshore County Road and Beverly Drive 

(fig. 43). 

3. For the scenario simulating the decrease of the Lake 

Michigan water level to the historical low of December 

23, 2007, results show little change from the original 

March 2013 distribution (fig. 44).

The results of this study can be used by water-resource 

managers to understand how surrounding ditches affect water 

levels in and around Great Marsh. The groundwater model 

developed in this study can be applied in the future to answer 

questions about how alterations to the drainage system in the 

area will affect water levels in and around the study area. The 

modeling methods developed in this study provide a template for other studies of groundwater flow and groundwater/

surface-water interactions within the shallow surficial aquifer in 

northern Indiana.
References Cited 91

References Cited

AECOM, 2010, Remedial investigation report—Pines area 

of Investigation, AOC II: Westford, Mass., docket no. 

V-W-’04-C-784, [variously paged], accessed June 19, 2015, 

at http://www.epa.gov/region05/cleanup/pines/pdfs/pines_

ri_201003_report.pdf.

Alley, W.M., Reilly, T.E., and Franke, O.L., 1999, Sustainability of ground-water resources: U.S. Geological Survey 

Circular 1186, 79 p.

Anderson, M.P., and Woessner, W.W., 1992, Applied groundwater modeling—Simulation of flow and advective transport: San Diego, Academic Press, 381 p. 

Arihood, L.D., and Cohen, D.A., 1998, Geohydrology and 

simulated ground-water flow in northwestern Elkhart 

County, Indiana: U.S. Geological Survey Water-Resources 

Investigations Report 97–4204, 47 p. 

Beaty, J.E., 1994, Water resource availability in the 

Lake Michigan Region, Indiana: Indiana Department 

of Natural Resources, Division of Water, Water Resource 

Assessment 94–4, 257 p.

Buszka, P.M., Cohen, D.A., Lampe, D.C., and Pavlovic, N.B., 

2011, Relation of hydrologic processes to groundwater and 

surface-water levels and flow directions in a dune-beach 

complex at Indiana Dunes National Lakeshore and Beverly 

Shores, Indiana: U.S. Geological Survey Scientific Investigations Report 2011–5073, 75 p.

Cooley, R.L., and Naff, R.L., 1990, Regression modeling of 

ground-water flow: U.S. Geological Survey Techniques of 

Water-Resources Investigations, book 3, chap. B4, 232 p.

Cunningham, W.L., and Schalk, C.W., comps., 2011, Groundwater technical procedures of the U.S. Geological Survey: 

U.S. Geological Survey Techniques and Methods book 1, 

chap. A1, 151 p.

Doss, P.K., 1993, The nature of a dynamic water table in a 

system of non-tidal, freshwater coastal wetlands: Journal of 

Hydrology, v. 141, nos. 1–4, p. 107–126. 

Duwelius, R.F., Yeskis, D.J., Wilson, J.T., and Robinson, B.A., 

2001, Geohydrology, water quality, and simulation of 

ground-water flow in the vicinity of a former waste-oil 

refinery near Westville, Indiana, 1997–2000: U.S. Geological Survey Water-Resources Investigations Report 01–4221, 

161 p.

Egler, A.L., Risch, M.R., Alvarez, D.A., and Bradley, P.M., 

2013, Organic wastewater compounds in water and sediment in and near restored wetlands, Great Marsh, Indiana 

Dunes National Lakeshore, 2009–11: U.S. Geological Survey Scientific Investigations Report 2013–5186, 52 p.

Fenelon, J.M., and Watson, L.R., 1993, Geohydrology and 

water quality of the Calumet aquifer, in the vicinity of the 

Grand Calumet River/Indiana Harbor Canal, northwestern 

Indiana: U.S. Geological Survey Water-Resources Investigations Report 92–4115, 151 p.

Fetter, C.W., 1994, Applied hydrogeology (3d ed.): New York, 

McMillian, 691 p.

Freeze, A.R., and Cherry, J.A., 1979, Groundwater: Englewood Cliffs, N.J., Prentice-Hall, 604 p.

Gillies, D.C., and Lapham, W.W., 1980, Reassessment of the 

effects of construction dewatering on ground-water levels in 

the Cowles Unit, Indiana Dunes National Lakeshore, Indiana—Supplement to Geological Survey Water-Resources 

Investigations 78–138: U.S. Geological Survey Open-File 

Report 80–1105, 50 p.

Grannemann, N.J., Hunt, R.J., Nicholas, J.R., Reilly, T.E., 

and Winter, T.C., 2000, The importance of ground water 

in the Great Lakes region: U.S. Geological Survey Water 

Resources Investigations Report 00–4008, 14 p.

Gray, H.H., 2000, Physiographic divisions of Indiana: Indiana 

Geological Survey Special Report 61, 15 p., 2 fig., 1 pl.

Greeman, T.K., 1995, Water levels in the Calumet aquifer 

and their relation to surface-water levels in northern Lake 

County, Indiana: U.S. Geological Survey Water Resources 

Investigations Report 94–4110, 61 p.

Harbaugh, A.W., Banta, E.R., Hill, M.C., and McDonald, M.G., 

2000, MODFLOW-2000, the U.S. Geological Survey 

modular ground-water model -- User guide to modularization concepts and the Ground-Water Flow Process: U.S. 

Geological Survey Open-File Report 00-92, 121 p.

Harbaugh, A.W., 2005, MODFLOW-2005, The U.S. Geological Survey modular ground-water model—The GroundWater Flow Process: U.S. Geological Survey Techniques 

and Methods, book 6, chap. A16 [variously paged].

Hartke, E.J., Hill, J.R., and Reshkin, Mark, 1975, Environmental geology of Lake and Porter Counties, Indiana—An 

aid to planning: Indiana Department of Natural Resources, 

Geological Survey Special Report 11, Environmental Study 

8, 57 p.

Hill, M.C., 1998, Methods and guidelines for effective model 

calibration; with application to UCODE, a computer 

code for universal inverse modeling, and MODFLOWP, 

a computer code for inverse modeling with MODFLOW: 

U.S. Geological Survey Water-Resources Investigations 

Report 98–4005, 90 p.
92 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

Hill, M.C., Banta, E.R., Harbaugh, A.W., and Anderman, 

E.R., 2000, MODFLOW-2000, the U.S. Geological Survey 

modular ground-water model—User guide to the Observation, Sensitivity, and Parameter-Estimation Processes and 

three post-processing programs: U.S. Geological Survey 

Open-File Report 00–184, 209 p.

Hill, M.C., and Tiedeman, C.R., 2007, Effective groundwater 

model calibration—With analysis of data, sensitivities, 

prediction, and uncertainty: Hoboken, N.J., John Wiley and 

Sons, 455 p.

Holmes, R.R., Terrio, P.J., Harris, M.A., and Mills, P.C., 2001, 

Introduction to field methods for hydrologic and environmental studies: U.S. Geological Survey Open-File Report 

01–05, 241 p.

Indiana Department of Natural Resources, 2014, Water well 

record database—Digital data, 2014: Division of Water, 

Water Rights and Use Section, accessed July 22, 2014, at 

http://www.in.gov/dnr/water/3595.htm.

Kay, R.T., Duwelius, R.F., Brown, T.A., Micke, F.A., and 

Witt-Smith, C.A., 1996, Geohydrology, water levels and 

directions of flow, and occurrence of light-nonaqueousphase liquids on ground water in northwestern Indiana 

and the Lake Calumet area of northeastern Illinois: 

U.S. Geological Survey Water-Resources Investigations 

Report 95–4253, 84 p. 

Lampe, D.C., and Bayless, E.R., 2013, Hydrologic data and 

groundwater flow simulations in the vicinity of Long Lake, 

Indiana Dunes National Lakeshore, near Gary, Indiana: 

U.S. Geological Survey Scientific Investigations Report 

2012–5003, 96 p.

Lapham, W.W., Wilde, F.D., and Koterba, M.T., 1997, Guidelines and standard procedures for studies of ground-water 

quality—Selection and supporting installation of wells and 

supporting documentation: U.S. Geological Survey WaterResources Investigations Report 96–4233, 110 p.

Lohman, S.W., and others, 1972, Definitions of selected 

ground-water terms—Revisions and conceptual refinements: U.S. Geological Survey Water-Supply Paper 1988, 

21 p.

Malott, C.A., 1922, The physiography of Indiana, in Handbook of Indiana geology: Indiana Department of Conservation Publication 21, part 2, p. 59–256.

Marie, J.R., 1976, Model analysis of effects on water levels 

at Indiana Dunes National Lakeshore caused by construction dewatering: U.S. Geological Survey Water-Resources 

Investigations Report 76–82, 32 p.

McDonald, M.G., and Harbaugh, A.W., 1988, A modular 

three-dimensional finite-difference ground-water flow 

model: U.S. Geological Survey Techniques of WaterResources Investigations, book 6, chap. A1, 586 p. 

Meyer, W.R., and Tucci, Patrick, 1979, Effects of seepage 

from fly-ash settling ponds and construction dewatering 

on groundwater levels in the Cowles Unit, Indiana Dunes 

National Lakeshore, Indiana: U.S. Geological Survey 

Water-Resources Investigations 78–138, 95 p.

Midwestern Regional Climate Center, 2014, Products and 

services—Online data—MACS, accessed July 22, 2014, 

at http://mcc.sws.uiuc.edu/.

Mulcare, D.M., 2004, NGS Toolkit, Part 9—The National 

Geodetic Survey VERTCON Tool: Professional Surveyor, 

v. 24, no. 3, 3 p., accessed March 2, 2012, at 

http://www.ngs.noaa.gov/TOOLS/Vertcon/vertcon.html.

National Oceanic and Atmospheric Administration, 1982, 

Monthly normals of temperature and precipitation, heating 

and cooling degree days, 1951–80, Indiana: Climatography 

of the United States No. 81, p.13.

National Oceanic and Atmospheric Administration, 1986–87, 

Climatological data, Indiana: v. 91–93 (published monthly).

National Oceanic and Atmospheric Administration, 2011, 

Verified daily mean water level data—9087044 Calumet 

Harbor, Lake Michigan, IL from 20130327 to 20130328 and 

20140428 to 20140429, accessed July 22, 2014, at 

http://co-ops.nos.noaa.gov/waterlevels.html?id=9087044. 

Niswonger, R.G.; Panday, Sorab; and Ibaraki, Motomu, 2011, 

MODFLOW-NWT, A Newton formulation for MODFLOW-2005: U.S. Geological Survey Techniques and 

Methods, book 6, chap. A37, 44 p.

Poeter, E.P., Hill, M.C., Banta, E.R., Mehl, Steffen, and Christensen, Steen, 2005, UCODE_2005 and six other computer 

codes for universal sensitivity analysis, calibration, and 

uncertainty evaluation: U.S. Geological Survey Techniques 

and Methods, book 6, chap. A11, 283 p.

Pollock, D.W., 2012, User guide for MODPATH version 6— 

A particle-tracking model for MODFLOW: U.S. Geological 

Survey Techniques and Methods, book 6, chap. A41, 58 p.

Rantz, S.E., and others, 1982, Measurement and computation 

of streamflow: U.S. Geological Survey Water Supply Paper 

2175, 2 v., 284 p.

Rosenshein, J.S., and Hunn, J.D., 1968, Geohydrology and 

ground-water potential of Lake County, Indiana: Indiana 

Department of Conservation, Division of Water Resources 

Bulletin 31, 36 p.
 93

Shedlock, R.J., Cohen, D.A., Imbrigiotta, T.E., and Thompson, 

T.A., 1994, Hydrogeology and hydrochemistry of dunes 

and wetland along the southern shore of Lake Michigan, 

Indiana: U.S. Geological Survey Open-File Report 92–139, 

85 p.

Shedlock, R.J., and Harkness, W.E., 1984, Shallow groundwater flow and drainage characteristics of the Brown Ditch 

basin near the East Unit, Indiana Dunes National Lakeshore, 

Indiana, 1982: U.S. Geological Survey Water-Resources 

Investigations Report 83–4271, 37 p.

Thompson, T.A., 1987, Sedimentology, internal architecture 

and depositional history of the Indiana Dunes National 

Lakeshore and State Park: Bloomington, Ind., Indiana 

University, unpublished Ph.D. thesis, 129 p.

Thompson, T.A., 1992, Beach-ridge development and lakelevel variation in southern Lake Michigan: Sedimentary 

Geology, v. 80, nos. 3–4, p. 305–318.

Trescott, P.C., Pinder, G.F., and Larson, S.P., 1976, Finitedifference model for aquifer simulation in two dimensions 

with results of numerical experiments, in Automated data 

processing and computations: U.S. Geological Survey Techniques of Water-Resources Investigations, book 7, chap. C1, 

116 p.

U.S. Army Corps of Engineers, 2012, Regional supplement to 

the Corps of Engineers wetland delineation manual—Northcentral and northeast region (ver. 2.0): Vicksburg, Miss., 

U.S. Army Engineer Research and Development Center, 

ERDC/EL TR-12-1, 175 p. 

U.S. Census Bureau, 2013, Population and sousing unit estimates, accessed June 3, 2013, at http://www.census.gov/

popest/.

U.S. Environmental Protection Agency, 2002, Methods for 

evaluating wetland condition—Introduction to wetland 

biological assessment: Washington, D.C., Office of Water, 

EPA-822-R-02-014, 35 p. 

U.S. Geological Survey, 1966, Topographic instructions of 

the United States Geological Survey—Leveling: U.S. Geological Survey Topographic Instructions, chaps., 2E1–2E5, 

63 p.

Warzyn Engineering, Inc., 1987, Agency review draft, 

remedial investigation report, Ninth Avenue Dump, Gary, 

Indiana: Omaha, Neb., U.S. Army Corps of Engineers 

contract no. DACW 45-86-C-0002, acting for U.S. Environmental Protection Agency [variously paged].

Watson, L.R., Shedlock, R.J., Banaszak, K.J., Arihood, L.D., 

and Doss, P.K., 1989, Preliminary analysis of the shallow 

ground-water system in the vicinity of the Grand Calumet 

River/Indiana Harbor Canal, northwestern Indiana: 

U.S. Geological Survey Open-File Report 88–492, 45 p.

Winter, T.C., 1983, The interaction of lakes with variably 

saturated porous media: Water Resources Research, v. 19, 

no. 5, p. 1203–1218.

Winter, T.C., 1999, Relation of streams, lakes, and wetlands 

to groundwater flow systems: Hydrogeology Journal, v. 7, 

no. 1, p. 28–45.

Appendix 1

Continuous and discrete water-level data collected at monitoring wells overlaid with land-surface 

elevation location; an elevation of 1 foot below land surface; and the growing season, May 2012 

through December 2013. For each figure (plot) in appendix 1, the altitude of the land surface 

above North American Vertical Datum of 1988 at the monitoring well is indicated by a horizontal 

green line. An altitude 1 foot lower than the land surface altitude is indicated by a red line, and 

the area between is shaded grey. The annual growing season also is represented on the hydrographs as green shaded areas. Plots can be used to interpret the presence and duration of a wetland condition at the sites where data were collected. See figure 8 for monitoring-well locations 

and table 2 for monitoring-well characteristics. 
94 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

EXPLANATION

Growing season

Area 1 foot below land surface at groundwater-monitoring well

Land-surface elevation at groundwater-monitoring well

Altitude 1 foot below land-surface elevation at groundwater-monitoring well

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2012 2013

Water-level altitude, in feet above North 

American Vertical Datum of 1988

Water-level altitude, in feet above North 

American Vertical Datum of 1988

Water-level altitude, in feet above North 

American Vertical Datum of 1988

USGS 414151086562701 DUNES WELL GM-35

USGS 414200086563402 WELL 607 BEVERLY CAROLINA AT BEVERLY SHORES, IN

USGS 414154086563102 WELL 608 NORTH DITCH CAROLINA AT BEVERLY SHORES IN

590

591

592

593

594

595

592

593

594

595

596

597

598

590

591

592

593

594

595

596

597

Figure 1–1. Graphs showing water-level data in comparison to land-surface elevation at U.S. Geological Survey (USGS) 

groundwater-monitoring wells 607, 608, and GM-35 near Indiana Dunes National Lakeshore, Indiana.
Appendix 1 95

EXPLANATION

Growing season

Area 1 foot below land surface at groundwater-monitoring well

Land-surface elevation at groundwater-monitoring well

Altitude 1 foot below land-surface elevation at groundwater-monitoring well

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2012 2013

Water-level altitude, in feet above North 

American Vertical Datum of 1988

Water-level altitude, in feet above North 

American Vertical Datum of 1988

Water-level altitude, in feet above North 

American Vertical Datum of 1988

USGS 414124086574101 WELL 606 MARSH MONTANA AT BEVERLY SHORES, IN

USGS 414140086571501 WELL 604 BEVERLY KANSAS AT BEVERLY SHORES, IN

USGS 414152086564901 WELL 605 BEVERLY CENTRAL AT BEVERLY SHORES, IN

596

597

598

599

600

594

595

596

597

598

599

600

601

602

603

Figure 1–2. Graphs showing water-level data in comparison to land-surface elevation at U.S. Geological Survey (USGS) 

groundwater-monitoring wells 604, 605, and 606 near Indiana Dunes National Lakeshore, Indiana.
96 Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore

EXPLANATION

Growing season

Area 1 foot below land surface at groundwater-monitoring well

Land-surface elevation at groundwater-monitoring well

Altitude 1 foot below land-surface elevation at groundwater-monitoring well

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2012 2013

Water-level altitude, in feet above North 

American Vertical Datum of 1988

Water-level altitude, in feet above North 

American Vertical Datum of 1988

Water-level altitude, in feet above North 

American Vertical Datum of 1988

USGS 414207086561601 DUNES WELL GM-37

USGS 414139086574101 WELL 609 ALYCE MONTANA AT BEVERLY SHORES, IN

USGS 414146086562301 WELL 610 TRAIL CAROLINA AT BEVERLY SHORES, IN

600

601

602

603

604

600

601

602

603

604

605

606

591

592

593

594

595

596

Figure 1–3. Graphs showing water-level data in comparison to land-surface elevation at U.S. Geological Survey (USGS) 

groundwater-monitoring wells 609, 610, and GM-37 near Indiana Dunes National Lakeshore, Indiana.
Appendix 1 97

EXPLANATION

Growing season

Area 1 foot below land surface at groundwater-monitoring well

Land-surface elevation at groundwater-monitoring well

Altitude 1 foot below land-surface elevation at groundwater-monitoring well

601

602

603

604

600

601

602

603

604

600

601

602

603

604

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

2012 2013

Water-level altitude, in feet above North 

American Vertical Datum of 1988

Water-level altitude, in feet above North 

American Vertical Datum of 1988

Water-level altitude, in feet above North 

American Vertical Datum of 1988

USGS 414132086574101 WELL 603 BEVERLY MONTANA AT BEVERLY SHORES, IN

USGS 414114086581601 WELL 601 LAKE SHORE CO RD AT BEVERLY SHORES, IN

USGS 414130086580301 WELL 602 BEVERLY DREXWOOD AT BEVERLY SHORES, IN

Figure 1–4. Graphs showing water-level data in comparison to land-surface elevation at U.S. Geological Survey (USGS) 

groundwater-monitoring wells 601, 602, and 603 near Indiana Dunes National Lakeshore, Indiana.

Front cover background. Photograph of Great Marsh west of Central Avenue and north of Brown 

Ditch, taken on June 11, 2013, by David C. Lampe.

Front cover inset upper left. Photograph of Brown Ditch near USGS Stream Gage Brown Ditch at 

Central Avenue (USGS 04095154), taken on April 29, 2014, by David C. Lampe.

Front cover inset lower right. Photograph of Brown Ditch west of Carolina Avenue, taken on June 

11, 2013, by David C. Lampe.

Back inner cover panorama. Photograph of Beaver dam in Brown Ditch near USGS Stream Gage 

Brown Ditch at Central Avenue (USGS 04095154), taken on December 20, 2013, by David C. Lampe.
ISSN 2328-0328 (online)

http://dx.doi.org/10.3133/sir20155141

Lampe—Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore—Scientific Investigations Report 2015–5141 Lampe—Hydrologic Data and Groundwater-Flow Simulations in the Brown Ditch Watershed, Indiana Dunes National Lakeshore—Scientific Investigations Report 2015–5141

ISSN 2328-0328 (online)

http://dx.doi.org/10.3133/sir20155141