Prepared in cooperation with the Muskingum Watershed Conservancy District and the 

City of Marietta, Ohio

Flood-Inundation Maps and Updated Components for a FloodWarning System for the City of Marietta, Ohio and Selected 

Communities along the Lower Muskingum River and Ohio River 

Scientific Investigations Report 2014–5195

U.S. Department of the Interior

U.S. Geological Survey
Cover: Looking northwest at Lock and Dam Number 6 and the State Route 266 (Broadway Street) bridge over the Muskingum River at 

Stockport, Ohio. Photo taken by US Geological Survey, September 2012.
Flood-Inundation Maps and Updated 

Components for a Flood-Warning System 

for the City of Marietta, Ohio and Selected 

Communities along the Lower Muskingum River 

and Ohio River

By Matthew T. Whitehead and Chad J. Ostheimer

Prepared in cooperation with the Muskingum Watershed Conservancy District 

and the City of Marietta, Ohio

Scientific Investigations Report 2014–5195

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, Acting Director

U.S. Geological Survey, Reston, Virginia: 2014

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Suggested citation:

Whitehead, M.T., and Ostheimer, C.J., 2014, Flood-inundation maps and updated components for a flood-warning system 

for the City of Marietta, Ohio and selected communities along the Lower Muskingum River and Ohio River: 

U.S. Geological Survey Scientific Investigations Report 2014–5195, 16 p., http://dx.doi.org/10.3133/sir20145195.

ISSN 2328-0328 (online)
iii

Contents

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

Introduction ....................................................................................................................................................1

Flood Forecasting and Predicting Peak Flood Stage......................................................................1

Description of the Study Area ............................................................................................................2

Purpose and Scope ..............................................................................................................................2

New Streamgages Component ...................................................................................................................4

River Bathymetry and Structural Geometry Component.........................................................................5

Hydraulic Structures ............................................................................................................................6

Hydraulic Modeling Component..................................................................................................................6

Topographic Data..................................................................................................................................6

Hydrologic Data.....................................................................................................................................6

Revisions to NWS HEC–RAS Model for Ohio River.........................................................................6

Muskingum River Model Development and Calibration.................................................................6

Hydraulic Model Quality Assurance ........................................................................................8

Muskingum River Mapping Reaches .....................................................................................10

Determination of Discharges for Water-Surface Profiles ...........................................................10

Effects of Backwater from the Ohio River......................................................................................12

Backwater Modeling Solution.................................................................................................12

Backwater Mapping Solution..................................................................................................12

Backwater Mapping Limitations and Error Analyses..........................................................12

Flood-Inundation Maps Component .......................................................................................15

Flood-Inundation Map Delivery........................................................................................................15

Disclaimer for Flood-Inundation Maps ...........................................................................................15

Uncertainties and Limitations Regarding Use of Flood-Inundation Maps ................................15

Summary........................................................................................................................................................15

References Cited..........................................................................................................................................16

Figures

1. Map showing Muskingum and Ohio Rivers and selected communities .............................3

2. Map showing locations of selected streamgages, and bathymetric and 

modeling reaches .........................................................................................................................4

3. Map showing locations of locks and dams, streamgages, and stage sensors .................7

4. Map showing locations of locks and dams and the mapping reaches for 

Muskingum River........................................................................................................................10

5. Map showing geographic areas for mapping of the Muskingum River from 

Beverly to Marietta.....................................................................................................................13

6. Plot showing two water-surface profiles from Scenario A, one water-surface 

profile from Scenario B, and the approximated water-surface profile constructed 

from normal-depth profile segments for two mapping area segments for the 

Muskingum River........................................................................................................................14
iv

Tables

1. Summary of characteristics of the selected streamgages in the study area ....................5

2. Differences in modeled stages and rating curve number 13 for the Muskingum 

River at McConnelsville (03150000) streamgage.....................................................................8

3. HEC–RAS model results compared to stage data collected for four flood events 

on the Muskingum River..............................................................................................................9

4. Approximate mapping reach limits and drainage areas for Reaches 1 and 2 of the 

Muskingum River........................................................................................................................11

5. Stages and elevations, with corresponding streamflow estimates at selected 

locations.......................................................................................................................................11

Conversion Factors, Vertical Datum, and Abbreviations

Multiply By To obtain

Length

inch (in) 0.0833 foot (ft)

foot (ft) 0.3048 meter (m)

meter (m) 3.281 foot (ft) 

mile (mi) 1.609 kilometer (km)

kilometer (km) 0.6214 mile (mi)

Area

square mile (mi2

) 2.590 square kilometer (km2) 

square kilometer (km2

) 0.3861 square mile (mi2)

Flow rate

cubic foot per second (ft3

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

cubic meter per second (m3

/s) 35.31 cubic foot per second (ft3/s)

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

(NAVD 88).
Flood-Inundation Maps and Updated Components for a FloodWarning System for the City of Marietta, Ohio and Selected 

Communities along the Lower Muskingum River and Ohio River

By Matthew T. Whitehead and Chad J. Ostheimer

Abstract 

Digital flood-inundation maps for lower reaches of the 

Muskingum River and a reach of the Ohio River in southeast 

Ohio were created by the U.S. Geological Survey (USGS), 

in cooperation with the Muskingum Watershed Conservancy 

District and the City of Marietta, Ohio. To complete the 

inundation maps, Ohio River and lower Muskingum River 

bathymetry was updated and two streamgages, one on the 

Ohio River upstream of Marietta near Sardis, Ohio, and one on 

the Muskingum River in Beverly, Ohio, were added as basic 

components of the flood-warning system. An updated hydraulic model component also led to the new flood-inundation 

maps. The maps, which can be accessed through the USGS 

Flood Inundation Mapping Science Web site at http://water.

usgs.gov/osw/flood_inundation/, depict estimates of the areal 

extent of flooding corresponding to water levels (stages) at 

one or more of the following USGS streamgages: Muskingum 

River at McConnelsville, Ohio (03150000); Muskingum River 

at Beverly, Ohio (03150500); and Ohio River at Marietta, 

Ohio (03150700). The maps can be used in conjunction with 

National Weather Service flood-forecast data to show areas of 

estimated flood inundation associated with forecasted floodpeak stages. 

Flood profiles for selected reaches were prepared by 

calibrating steady-state step-backwater models to selected 

streamgage rating curves. The step-backwater models were 

used to determine water-surface-elevation profiles for up to 

12 flood stages at a streamgage with corresponding streamflows ranging from approximately the 10- to 0.2-percent 

chance annual-exceedance probabilities for each of the 3 

streamgages that correspond to the flood-inundation maps. 

Additional hydraulic modeling was used to account for the 

effects of backwater from the Ohio River on water levels in 

the Muskingum River. The computed longitudinal profiles of 

flood levels were used with a Geographic Information System 

digital elevation model (derived from light detection and ranging) to delineate flood-inundation areas. Digital maps showing 

flood-inundation areas overlain on digital orthophotographs 

were prepared for the selected floods. 

Introduction 

Marietta, Ohio was established in 1788 at the confluence 

of the Ohio and Muskingum Rivers and has been affected by 

flooding from both rivers since its origins. Ohio River flooding 

in Marietta has been well documented with two of the most 

severe floods occurring in March 1913 and January 1937, 

with peak-flood stages1 recorded at 58.30 and 55.00 feet (ft), 

respectively (National Weather Service [NWS], 2012). More 

recently, Marietta experienced significant flooding in September 2004 and January 2005, when peak-flood stages at the U.S. 

Geological Survey (USGS) streamgage on the Ohio River at 

Marietta (USGS streamgage number 03150700) reached 44.97 

and 43.60 ft, respectively. These floods inundated hundreds 

of homes and businesses and severely impacted Marietta. The 

NWS has established flood-severity categories and considers 

flood stages at, or above, 40 ft at Marietta as “major” (indicating extensive inundation and property damage and characterized by the evacuation of people and livestock and the closure 

of both primary and secondary roads). Since 1913, 7 Ohio 

River floods have met or exceeded a stage of 40 ft. 

Flood Forecasting and Predicting Peak Flood 

Stage

The NWS has statutory responsibility for hydrologic 

forecasts throughout the nation. Peak-stage forecasts are 

based partly on data from a network of precipitation gages 

and streamgages. In Ohio, the hydrologic forecasts originate 

with either the NWS Ohio River Forecast Center (OHRFC) in 

Wilmington, Ohio or the NWS North Central Forecast Center 

in Chanhassen, Minnesota. Flood warnings for Ohio are issued 

to the public by regional NWS offices in Wilmington, Ohio, 

Cleveland, Ohio, Charleston, West Virginia, Pittsburgh, Pennsylvania, or Syracuse, Indiana. For Marietta and communities 

1

 Stage refers to a stream’s height above a reference point. Stage, together 

with a reference datum, can be used to determine water-surface elevation.
2 Flood-Inundation Maps for a Flood-Warning System for Selected Communities along the Lower Muskingum River and Ohio River

along the lower Muskingum River, the hydrologic forecasts 

originate with the OHRFC and flood warnings are issued by 

the Charleston, West Virginia office of the NWS.

The NWS uses forecast models to estimate the quantity 

and timing of water flowing through selected stream reaches 

in the United States. These forecast models (1) estimate the 

amount of runoff generated by precipitation and snowmelt, (2) 

simulate the movement of floodwater as it proceeds downstream, and (3) predict the flow and stage (and water-surface 

elevation) for the stream at a given location (Advanced Hydrologic Prediction Service [AHPS] forecast point) throughout 

the forecast period (every 6 hours and 3 to 5 days in the future 

for many locations). For more information on AHPS forecasts, 

please see: http://water.weather.gov/ahps/pcpn_and_river_

forecasting.pdf. 

Flood-prone communities can benefit from advanced 

predictions of peak flood stage; however, predicted flood stage 

is an abstract concept that becomes meaningful only when 

understood in terms of areas that will be inundated by flood 

waters. By using USGS streamgage data along with hydraulic 

modeling and digital-elevation data (land surface topography), 

a library of flood-inundation boundaries can be predetermined 

for a series of flood stages. The library can be used with NWS 

predicted flood stages and digital orthophotographs to help 

visualize expected flood areas well in advance of occurrence 

of the flood peak. Two Web-based applications that serve 

predicted flood stages along with a corresponding library 

of flood boundaries overlain on orthophotographs are available: the AHPS of the NWS at http://www.nws.noaa.gov/oh/

ahps/ and the Flood-Inundation Mapper (FIM) of the USGS 

at http://wim.usgs.gov/FIMI/FloodInundationMapper.html. 

Inclusion of data pertinent to Marietta and other communities 

along the lower Muskingum River into FIM and AHPS will 

help disseminate important and dynamic information to both 

emergency managers and the public, so they can take preventive measures to minimize flood damages.

Description of the Study Area

The Muskingum River is the largest watershed entirely 

contained within Ohio and has a contributing drainage area of 

8,050 square miles (mi2; USGS, 2012). The lower Muskingum 

River, located in Morgan and Washington Counties, drains to 

the Ohio River through the communities of McConnelsville, 

Malta, Stockport, Beverly, Waterford, Coal Run, Lowell, 

Devola, Oak Grove, and Marietta (fig. 1). 

Marietta is in Washington County (fig. 1) at the confluence of the Ohio and Muskingum Rivers. The villages of 

McConnelsville and Malta are in central Morgan County 

roughly 25 miles (mi) northwest of Marietta, along the Muskingum River. The villages of Stockport, Beverly, Waterford, 

Coal Run, Lowell, Devola, and Oak Grove are along the 

Muskingum River between McConnelsville and Marietta. In 

addition to these communities, many private residences and 

small commercial properties are within the floodplains of the 

lower Muskingum River. In 2010, the populations of Morgan 

and Washington Counties were 15,054 and 61,778, respectively (U.S. Census Bureau, 2012a and 2012b); the population 

of Marietta was 14,085 (U.S. Census Bureau, 2012c).

Purpose and Scope

Flood-warning systems typically involve many major 

elements including streamflow and precipitation gage networks, hydrologic and hydraulic modeling, flood-inundation 

mapping, and various means of disseminating flood-warning 

information. This report describes a study of components for 

improving the flood-warning system for selected reaches of 

Muskingum River and Ohio River in southeast Ohio. The 

study included the enhancement of the streamgage network, 

hydraulic modeling, and development of new flood-inundation 

mapping. A primary goal of this study was to develop tools 

to provide advanced flood warning for the communities of 

McConnelsville, Malta, Stockport, Beverly, Waterford, Coal 

Run, Lowell, Devola, Oak Grove, and Marietta, Ohio. 

This report describes (1) the installation of one new 

streamgage on the Ohio River upstream of Marietta near 

Sardis, Ohio and (2) one new streamgage on the Muskingum 

River in Beverly, Ohio, (3) collection of updated bathymetric 

data for a 75-mi reach of the Ohio River, (4) collection of 

bathymetric and bridge geometric data for development of a 

hydraulic model for the Muskingum River, (5) development 

of flood-inundation boundaries depicting the areal extent 

of flooding expected to occur for selected stages at selected 

USGS streamgages based on steady-state2

 model estimates and 

(6) the flood-inundation boundaries provided to the FIM and 

NWS for inclusion on their respective Web pages.

2

 Steady-state flow for this report refers to gradually varied steady-state 

flow in which there may be small variations in flow variables such as area and 

conveyance with respect to distance but for which all flow variables remain 

constant with respect to time. Unsteady-state flow refers to gradually varied 

unsteady-state flow in which there are not only small variations in flow variables with respect to distance but also changes in flow variables with respect 

to time (Franz and Melching, 1997).
Introduction 3

MORGAN River

McConnelsville

Malta

Stockport

Beverly

Waterford

Coal Run

Lowell

Devola

Oak

Grove Marietta

Muskingum

Ohio

River

WEST VIRGINIA

NOBLE

WASHINGTON

MONROE Hannibal

Belleville

MORGAN

2,100,000 2,200,000 2,300,000 2,400,000

400,000 500,000 600,000

Base from U.S. Geological Survey digital data, variously scaled, 2007

State Plane Coordinate System (feet), Ohio South, NAD83 Datum

Map area

OHIO

EXPLANATION

0 5 10 MILES

0 5 10 KILOMETERS

Corporate limits

County boundaries

Rivers

Figure 1. Muskingum and Ohio Rivers and selected communities.
4 Flood-Inundation Maps for a Flood-Warning System for Selected Communities along the Lower Muskingum River and Ohio River

New Streamgages Component

As part of this study, the USGS installed two new 

streamgages (fig. 2): Ohio River above Sardis (03114306) and 

Muskingum River at Beverly, Ohio (03150500). The Ohio 

River above Sardis (03114306) streamgage was installed near 

the former Lock #15, about 2.7 mi downstream of the Hannibal Lock and Dam (Ohio River mile 126.4). Regular streamflow measurements are now being made at this site to develop 

an index-velocity rating that relates an index velocity to the 

mean velocity of the cross section. The USGS will continue to 

make periodic streamflow measurements to facilitate the computation of continuous streamflow data necessary for accurate 

flood warnings. Due to the hydraulic characteristics of the 

Ohio River, especially at lower flows, standard USGS stagedischarge gaging equipment and techniques cannot be used. 

Therefore, the Sardis site was equipped with an acoustic Doppler current-velocity meter. A stage-area rating and an indexvelocity rating are used to compute streamflow at this site. 

The USGS Muskingum River at Beverly, Ohio 

(03150500) streamgage was installed approximately 4 mi 

downstream from the discontinued streamgage, Muskingum 

River near Beverly (03150300), which operated from April 

1993 to September 1999. It is equipped with a Geostationary 

Operational Environmental Satellite (GOES) transmitter. Data 

are transmitted via GOES hourly to facilitate near-real-time 

monitoring of equipment performance and stage. 

Streamflow and stage data from these new streamgages, 

as well as other USGS streamgages in Ohio, can be accessed 

by interested parties on the USGS Web-based data portal at 

http://waterdata.usgs.gov/oh/nwis/rt and also are available 

by email or text alert sent by the USGS WaterAlert program3

(http://maps.waterdata.usgs.gov/mapper/wateralert/). Characteristics of the selected streamgages in the study area are 

summarized in table 1.

3

 The USGS WaterAlert program is a service that sends e-mail or text 

messages when certain parameters, as measured by a USGS real-time data 

collection station, exceed user-definable thresholds. 

River

MORGAN

Muskingum

Ohio

River

WEST VIRGINIA

NOBLE

WASHINGTON

MONROE

ATHENS

MEIGS

2,100,000 2,200,000 2,300,000 2,400,000

400,000 500,000 600,000

Ohio River

at Marietta

(03150700)

Muskingum River

at Beverly

(03150500)

Muskingum River

at McConnelsville

(03150000)

Ohio River

above Sardis

(03114306)

Base from U.S. Geological Survey digital data, variously scaled, 2007

State Plane Coordinate System (feet), Ohio South, NAD83 Datum

Map area

OHIO EXPLANATION

0 5 10 MILES

0 5 10 KILOMETERS

County boundary

Rivers

Bathymetric data reaches

Model reaches

Streamgages

Figure 2. Locations of selected streamgages, and bathymetric and modeling reaches.
River Bathymetry and Structural Geometry Component 5

Table 1. Summary of characteristics of the selected streamgages in the study area.

 [mi2, square miles; NWS, National Weather Service; mi2, square miles]

Streamgage name Site number Drainage area

(mi2

) Period of record NWSforecast point Comment

Ohio River at Marietta, Ohio 03150700 35,590 2005–present Yes

Ohio River above Sardis, Ohio 03114306 26,156 2012–present No New site.

Muskingum River at Beverly, Ohio 03150500 7,947 2013–present Yes1 New site.

Muskingum River near Beverly, Ohio 03150300 7,627 1993–99 No Discontinued.

Muskingum River at McConnelsville, Ohio 03150000 7,422 1921–92

2001–present Yes

1

 The NWS plans to forecast peak stage at this location.

River Bathymetry and Structural 

Geometry Component

An unsteady flow model was developed for the Ohio 

River through a cooperative effort by the U.S. Army Corps of 

Engineers (USACE) and the NWS (Debra Lee, USACE Great 

Lakes and Ohio River Division, and Tom Adams, NWS-Ohio 

River Forecast Center, verbal communication, 2012). The 

Ohio River model is currently operational and used on a regular basis by the USACE and NWS. However, the USACE and 

NWS indicated a need for updated bathymetric data to help 

improve upon model accuracy. 

The USGS collected new bathymetric data (fig. 2) for a 

75-mi reach of the Ohio River (from just upstream from the 

Belleville Lock and Dam upstream to the Hannibal Lock and 

Dam) and for a 52-mi reach of the lower Muskingum River 

(from the confluence with the Ohio River to 2 mi upstream 

from the northern corporate limits of McConnelsville). The 

bathymetric data were obtained at intervals of approximately 

every 1⁄2 mi on both rivers. For the Ohio River, the bathymetric data were obtained at locations of the cross sections in the 

hydraulic model obtained from the NWS. Global Positioning System (GPS) surveys were simultaneously conducted to 

determine water-surface elevations at the time of bathymetric 

data collection to determine channel bottom elevations.

Bathymetric surveys were made by way of a 19-ft boat 

with a 2-inch pipe mount that was used to affix the acoustic 

equipment and software used to collect the bathymetric data. A 

210-kilohertz (kHz) AirmarTM transducer and a NavisoundTM 

210 Reson echo sounder were used for the collection of the 

depth information. A TrimbleTM Differential Global Positioning System (DGPS) was used for horizontal positioning during 

the survey. The HYPACKTM navigation software package 

installed on a laptop computer was used to integrate the depths 

and the DGPS horizontal position data and to display the location of the boat on a georeferenced aerial photo for navigation, 

and a laser rangefinder computed distance measurements and 

was used with a compass module, enabling determination of 

accurate azimuths and delineation of the shoreline.

Raw bathymetric data were processed within HYPACKTM 

to filter (1) problems related to the echo sounder processing a 

multiple-return acoustic signal in shallow water, which causes 

the measured depth to be twice the actual depth; (2) invalid 

GPS positions; and (3) redundant areas along the banks caused 

by overlap of data collection at the ends of various cross sections. Analog printouts of the bottom profiles were produced 

during data collection and used as a quality-assurance measure 

in bathymetric data processing, because multiple-return errors 

can be identified in the analog printouts. The data were first 

reviewed and filtered within HYPACKTM and then were compared to all supporting field notes and analog printouts. The 

processed bathymetric data (including edge-of-water points) 

were exported from HYPACKTM into a text file that included 

geographic coordinates and a corresponding depth. 

The bathymetric survey was quality assured by using 

the echo sounder and a bar-check method. The NavisoundTM 

210 Reson echo sounder has an accuracy of 0.03 ft at 210 

kHz (Reson, Inc., 2005). A built-in bar-check utility enabled 

depth verification by using a correction for the speed of sound. 

The USACE suggests performing the bar-check procedure to 

ensure the adequate calibration of an echo sounder (USACE, 

2002b). Bar checks of the echo sounder at multiple depths 

were conducted by lowering a 2-ft by 4-ft plate to known 

depths between 5 and 30 ft at 5-ft increments. The echo 

sounder always reported within plus or minus 0.3 ft of the 

bar check. The bar-check process was done twice throughout 

the day, one at the beginning and one at the end, to ensure 

accurate data collection (Hittle and Ruby, 2008). The survey 

was completed on calmer days to minimize the effects of wave 

action on the accuracy of the depth data. The vertical accuracy 

of the echo sounder was conservatively estimated to be plus or 

minus 0.5 ft.

Simultaneous to the bathymetric data collection, additional personnel were collecting water surface elevations by 

using a survey-grade GPS receiver and a real-time network 
6 Flood-Inundation Maps for a Flood-Warning System for Selected Communities along the Lower Muskingum River and Ohio River

developed by the Ohio Department of Transportation (Ohio 

Department of Transportation, 2014). Redundant occupations 

of water-surface elevations and published vertical benchmarks 

were used to verify GPS elevations and the real-time network 

accuracy. Data for this effort were collected in the summer of 

2012, before USGS Techniques and Methods 11–D1 (Rydlund 

and Densmore, 2012) was published. The GPS surveys do not 

meet the specifications for a Real Time Level III survey, as the 

occupation times were less than the required 180 epochs. A 

root mean square error analysis of known vertical benchmarks 

in the study reach indicated an accuracy of the water-surface 

elevations to be +/- 0.10 ft. The water-surface elevations were 

used with the bathymetric data to determine channel-bottom 

elevations. 

Hydraulic Structures

Fourteen structures, consisting of 7 road crossings, 1 

railroad bridge, and 6 low-head dams, have the potential to 

affect water-surface elevations during floods along the stream. 

Bridge-geometry data were obtained from field surveys 

conducted by personnel from the USGS Ohio Water Science 

Center. As with the bathymetric data collection, the structure 

geometries were collected in the summer of 2012, using the 

same survey-grade GPS and survey techniques. Hydraulic 

structure surveys and bathymetric data are on file at the USGS 

office in Columbus, Ohio.

Hydraulic Modeling Component

All hydraulic analyses were done with HEC–RAS version 4.1.0 (USACE, 2010). HEC–RAS is a one-dimensional 

step-backwater model used to compute water-surface profiles 

with steady-state or unsteady-state flow computation options. 

All hydraulic analyses for this report were done with the 

steady-state flow computation option.

Topographic Data

All topographic data used in this study are referenced 

vertically to NAVD88 and horizontally to the North American 

Datum of 1983. Cross-section elevation data were obtained 

from a digital elevation model (DEM) that was derived from 

light detection and ranging (lidar) data that were collected 

during March and May of 2007 by Woolpert Inc., Columbus, Ohio. The lidar data have a vertical accuracy of 1.0 ft a 

95-percent confidence level for the “open terrain” land-cover 

category (root mean squared error of 0.5 ft.). By these criteria, 

the lidar data support production of 2ft contours (Dewberry, 

2012); By using HEC–GeoRAS, a set of procedures, tools, and 

utilities for processing geospatial data in ArcGIS, elevation 

data were extracted from the DEM for cross sections and subsequently were input to the HEC–RAS model. The grid data 

from Ohio Geographically Referenced Information Program 

(Ohio Geographically Referenced Information Program, 2007) 

was converted into 2-ft contours by USGS personnel.

Hydrologic Data

For the Muskingum River at McConnelsville streamgage 

(03150000), the stage-discharge relation (rating curve) has 

undergone only minor revisions over the 83-year history of the 

gage. For this project, rating number 13 (stages 0.9 ft to 13.8 

ft) was the current rating used for calibration of the Muskingum River HEC–RAS model. 

For the Muskingum River at Beverly (03150500) location, the rating curve was determined by using the HEC–RAS 

model developed for the Muskingum River. The rating from 

the discontinued streamgage Muskingum River near Beverly 

(03150300) could not be used because the features that control 

the stage-discharge relation differ between the two sites. As of 

writing this report (June 2014), 12 streamflow measurements 

have been made at the Beverly gage (03150500), ranging in 

stage from 15.39 ft to 26.51ft, and each measurement has 

agreed with the rating developed with HEC–RAS within the 

streamflow measurement error.

Revisions to NWS HEC–RAS Model for 

Ohio River

In-channel data in the HEC–RAS model obtained from 

the NWS were revised for most of the cross sections within 

a 75-mi reach of the Ohio River based on USGS bathymetry 

data. Next, the hydraulic computations for the HEC–RAS 

model were changed from unsteady flow to steady-state. 

As a result of this change, a different downstream boundary 

condition was needed. The downstream boundary condition 

for the steady-state model was set to be a slope-conveyance 

(normal-depth) computation with a value of 0.00008 ft/ft estimated from the average streambed slope as determined from 

field surveys. Lastly, the HEC–RAS model was shortened to 

include only the area within Marietta (around 4 mi in length). 

The modeling and mapping study reach of the Ohio River 

extends from approximately 1.4 mi downstream of the Muskingum River, to 2.6 mi upstream (fig. 2). No other modifications were made to the Ohio River HEC–RAS model obtained 

from NWS.

Muskingum River Model Development and 

Calibration

The Muskingum River HEC–RAS model was constructed as a single reach from the mouth (confluence with 

Ohio River) upstream to McConnelsville, a reach length of 

approximately 52 mi. The downstream boundary condition for 

the Muskingum River HEC–RAS model was also set to be a 

slope-conveyance (normal-depth) computation with a value 
Hydraulic Modeling Component 7

of 0.00023 ft/ft estimated from the average streambed slope 

as determined from the bathymetric data. In-channel data for 

cross sections where bathymetry data were not collected were 

approximated by inserting a trapezoidal area. The in-channel 

areas and bottom elevations were based on the overall shape 

and average channel-bottom elevation of the bounding bathymetric data.

The model was initially calibrated to the available rating 

curve for the Muskingum River at McConnelsville (03150000) 

streamgage and the 13 streamflow measurements made for the 

Muskingum River at Beverly (03150500) streamgage. For the 

calibration, Manning’s roughness coefficients were adjusted 

from original field estimates until the results of the hydraulic 

computations closely agreed with the stage-discharge rating at 

McConnelsville. Final Manning’s roughness coefficients range 

in value from 0.028 to 0.038 for the main channel and from 

.046 to 0.150 for the overbanks. 

Additional calibration information was obtained by 

installing stage sensors (pressure transducers) in May 2013 at 

12 locations along the modeled reach of the Muskingum River 

(fig. 3). The stage sensors were located to obtain water-surface 

elevations (a) just upstream and downstream of each of the 

locks and dams, (b) in the middle of a reach between lock 

and dam numbers 3 and 4, and (c) at the upstream modeling 

limit. Surveys were conducted to establish the vertical datum 

of each stage sensor relative to the North American Vertical 

Datum of 1988 (NAVD88). The stage sensor elevations were 

checked, data were downloaded, and the sensors were cleaned 

several times during their deployment. The stage sensors were 

removed in November 2013.

The 12 stage sensor sites plus the two full time 

streamgages allowed for additional model calibration to measured stage data from several events for numerous locations 

#

#

#

"/

"/

"

"//

"/

"/

"/

"/ "/

"/"/

"/

NOBLE

Ohio

River

River

Muskingum

MORGAN

WASHINGTON

Ohio River

at Marietta

(03150700)

Muskingum River

at Beverly

(03150500)

Muskingum River

at McConnelsville

(03150000)

Lock and Dam

Number 2

Lock and Dam

Number 4

Lock and Dam

Number 3

Lock and Dam

Number 5

Lock and Dam

Number 6

Lock and Dam

Number 7

WEST

VIRGINIA

2,150,000 2,200,000 2,250,000

550,000 600,000

Map area

OHIO

#

"/

EXPLANATION

County boundaries

Rivers

Locks and dams

Stage sensors

Streamgages

Base from U.S. Geological Survey digital data, variously scaled, 2007

State Plane Coordinate System (feet), Ohio South, NAD83 Datum

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

Figure 3. Locations of locks and dams, streamgages, and stage sensors.
8 Flood-Inundation Maps for a Flood-Warning System for Selected Communities along the Lower Muskingum River and Ohio River

along the 52-mi modeling reach of the Muskingum River. 

Four flood peaks on June 28, July 11, July 13, and July 24 

were recorded during the 6 months of sensor deployment. 

When the stage sensors were serviced in October 2013, two 

appeared to be clogged with debris, and it was assumed that 

the data collected since the previous peak flood event on July 

24, 2013, were erroneous (table 2). Discharge values used 

to calibrate the HEC–RAS model for the four events were 

obtained directly from the Muskingum River at McConnelsville (03150000) rating curve number 13 and the Muskingum 

River at Beverly (03150500) rating curve developed for this 

study. After calibration, the modeled elevations matched the 

measured elevation data obtained from the sensors (not including the data from the likely clogged sensors) and streamgages 

on average within 0.14 ft, with a maximum difference of 

0.44 ft (table 2). 

Hydraulic Model Quality Assurance 

As part of the calibration process, model output warnings presented by HEC–RAS were reviewed. The results were 

assessed for validity, accuracy, and appropriate engineering 

practices. Some of the areas of concern included: (1) critical 

water-surface calculations, (2) water-surface elevation differences between adjacent cross-sections, and (3) correct usage 

of ineffective flow areas. All warnings generated by HEC–

RAS were reviewed and judged acceptable. The 1-D HEC–

RAS model checklist (USGS, 2014a) was followed to assist in 

the quality assurance process.

Table 2. Differences in modeled stages and rating curve number 13 for the Muskingum River at McConnelsville (03150000) streamgage. 

[ft3/s, cubic feet per second; ft, feet]

Streamflow from

rating number 13 used in 

HEC–RAS model (ft3

/s)

Stage from rating

(ft)

Stage from model

(ft)

Difference from rating

(ft)

18,650 7.00 6.96 -0.04

24,000 8.00 8.03 0.03

29,300 9.00 9.00 0.00

35,000 10.00 10.00 0.00

41,300 11.00 10.99 -0.01

47,900 12.00 12.00 0.00

54,800 13.00 12.99 -0.01

60,600 13.80 13.77 -0.03
Hydraulic Modeling Component 

9

Table 3. HEC–RAS model results compared to stage data collected for four flood events on the Muskingum River. [All elevation data are shown in feet above the North American Vertical Datum of 1988. Bolded values indicate data that are likely in error due to clogged sensors and are thus assumed incorrect. River mile refers to miles above the mouth of the Muskingum River. Delta refers to the difference in elevation between the model results and the measured data]

Flood event

June 28, 2013 July 11, 2013 July 13, 2013 July 24, 2013

Stage 

measurement 

device

River

mile

Model

elevation

Measured

elevation Delta Model elevation Measured elevation Delta Model elevation Measured elevation Delta Model elevation Measured elevation Delta

Stage sensor 5.5 590.47 590.34 0.13 596.33 596.11 0.22 591.84 591.96 -0.12 593.83 593.39 0.44

Stage sensor 13.4 601.11 601.24 -0.13 606.26 606.67 -0.41 602.94 603.07 -0.13 606.13 606.13 0.00

Stage sensor 14.1 610.79 610.68 0.11 612.53 612.43 0.10 611.40 611.35 0.05 612.50 612.35 0.15

Stage sensor 18.5 612.30 612.06 0.24 615.64 615.64 0.00 613.46 613.40 0.06 615.59 615.55 0.04

Beverly 

streamgage

24.1 615.78 615.75 0.03 620.92 620.91 0.01 617.65 617.61 0.04 620.85 620.85 0.00

Stage sensor 25.1 621.49 621.42 0.07 623.37 623.46 -0.09 622.56 622.43 0.13 623.21 623.97 -0.76

Stage sensor 33.7 626.06 625.70 0.36 629.24 629.53 -0.29 628.21 628.01 0.20 628.77 629.81 -1.04

Stage sensor 34.0 631.67 631.73 -0.06 633.02 633.15 -0.13 632.59 632.64 -0.05 632.78 632.91 -0.13

Stage sensor 39.7 635.40 635.28 0.12 638.13 638.22 -0.09 637.31 637.25 0.06 637.67 637.75 -0.08

Stage sensor 40.0 643.74 643.89 -0.15 645.09 645.44 -0.35 644.70 644.91 -0.21 644.87 645.14 -0.27

Stage sensor 49.2 648.74 648.67 0.07 651.77 652.17 -0.40 650.88 651.07 -0.19 651.27 651.54 -0.27

McConnelsville 

streamgage

49.3 657.19 657.19 0.00 658.98 659.11 -0.13 658.44 658.51 -0.07 658.68 658.78 -0.10

Stage sensor 52.2 658.07 657.77 0.30 660.30 660.36 -0.06 659.64 659.58 0.06 659.93 659.94 -0.01
10 Flood-Inundation Maps for a Flood-Warning System for Selected Communities along the Lower Muskingum River and Ohio River

Muskingum River Mapping Reaches

After calibration, the hydraulic modeling of the Muskingum River focused on two distinct reaches (fig. 4). Mapping 

Reach 1 extends from the mouth of the Muskingum River 

upstream through Lock and Dam Number 4 in Beverly and is 

approximately 26 mi in length. Mapping Reach 2 extends from 

2.1 mi downstream from Lock and Dam Number 6 near Stockport upstream to 3.4 mi upstream from Lock and Dam Number 

7 in McConnelsville and is approximately 14 mi in length. 

For each Mapping Reach, a single discharge value was 

used (that is, discharge was not varied along the reach). This 

use of a single discharge was justified due to the small difference in drainage areas between the top and bottom of each 

reach (table 4). Discharge values from rating number 13 of the 

Muskingum River at McConnelsville (03150000) streamgage 

were used for Mapping Reach 2, and discharge values from 

the rating curve developed for this study for Muskingum River 

at Beverly (03150500) were used as for Mapping Reach 1.

Determination of Discharges for Water-Surface 

Profiles

For the Ohio River and Mapping Reach 1of the Muskingum River, streamflows corresponding to the selected 

even-foot stage values were determined by use of an iterative 

process wherein the streamflows were varied in the HEC–RAS 

model until the modeled stages (elevations) equaled the target 

stages (table 5). Eleven water-surface profiles were generated for the Ohio River, and 12 profiles were generated for 

Muskingum Mapping Reach 1. The range in discharge values 

extends from approximately the 10-percent annual exceedance 

to the 0.2-percent annual exceedance probabilities. For Reach 

2 of the Muskingum River, 12 streamflows corresponding to 

the desired even-foot stage values (table 5) were taken from 

rating 13 for McConnelsville. These discharge values also 

extend from approximately the 10-percent annual exceedance 

to the 0.2-percent annual exceedance probabilities. Stages 

above 13.0 ft for the Muskingum River at McConnelsville, 

Ohio (03150000) are outside the range of rating 13.

NOBLE

Ohio

River

River

Muskingum

Lock and Dam

Number 2

Lock and Dam

Number 4

Lock and Dam

Number 3

Lock and Dam

Number 5

Lock and Dam

Number 6

Lock and Dam

Number 7

Muskingum River

Mapping Reach 2

Muskingum River

Mapping Reach 1

Ohio River

Mapping Reach

WASHINGTON

MORGAN

2,150,000 2,200,000 2,250,000

550,000 600,000

EXPLANATION

County boundaries

Rivers

Mapping reaches

Locks and dams

OHIO

Map area

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

Base from U.S. Geological Survey digital data, variously scaled, 2007

State Plane Coordinate System (feet), Ohio South, NAD83 Datum

Figure 4. Locations of locks and dams and the mapping reaches for Muskingum River.
Hydraulic Modeling Component 11

Table 4. Approximate mapping reach limits and drainage areas for Reaches 1 and 2 of the Muskingum River. 

[River mile refers to miles above the mouth of the Muskingum River. mi, mile; mi2, square miles; ft, feet]

Reach number Reach limit 

type Nearby location River mile Drainage area(mi2

)

Reach 1

Downstream Mouth of Muskingum River in Marietta 0.0 8,050

Upstream 0.9 mi upstream from Lock and Dam Number 4 near Beverly 25.9 7,710

Reach 2

Downstream 2.1 mi downstream from Lock and Dam Number 6 near 

Stockport 39.1 7,460

Upstream 3.4 mi upstream from Lock and Dam Number 7 in 

McConnelsville 52.7 7,410

Table 5. Stages and elevations, with corresponding streamflow estimates at selected locations. 

[All elevation data are shown in feet above the North American Vertical Datum of 1988. Bolded values indicate values above rating 13 for the 

Muskingum River at McConnelsville (03150000) streamgage. ft, feet; ft3/s, cubic feet per second]

Ohio River at Marietta (03150700)

Stage (ft) 34.0 36.0 38.0 40.0 42.0 44.0 46.0 48.0 50.0 52.0 54.0

Elevation (ft) 600.1 602.1 604.1 606.1 608.1 610.1 612.1 614.1 616.1 618.1 620.1

Streamflow

(in thousand ft3

/s) 320 345 375 407 440 476 515 552 590 632 672

Muskingum River at Beverly (03150500)

Stage (ft) 26.0 28.0 30.0 32.0 34.0 36.0 38.0 40.0 42.0 44.0 46.0 48.0

Elevation (ft) 618.6 620.6 622.6 624.6 626.6 628.6 630.6 632.6 634.6 636.6 638.6 640.6

Streamflow

(in thousand ft3

/s) 34.4 42.4 51.1 61.3 72.5 85.2 100 115 131 148 167 186

Muskingum River at McConnelsville (03150000)

Stage (ft) 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0 20.0

Elevation (ft) 658.6 659.6 660.6 661.6 662.6 663.6 664.6 665.6 666.6 667.6 668.6 669.6

Streamflow

(in thousand ft3

/s) 29.3 35.0 41.3 47.9 54.8 62.3 70.9 79.8 88.7 96.9 104 112
12 Flood-Inundation Maps for a Flood-Warning System for Selected Communities along the Lower Muskingum River and Ohio River

Effects of Backwater from the Ohio River

High stages on the Ohio River can create backwater conditions on the Muskingum River that extend upstream as far as 

Lock and Dam Number 4 in Beverly (approximately 25 mi). 

Backwater causes water-surface elevations to increase relative 

to nonbackwater conditions; however, the amount of increase 

varies depending on the stage of the Ohio River, the magnitude of streamflow on the Muskingum River, and location. 

Because of the potential for backwater from the Ohio River, a 

decision was made to complete additional hydraulic analyses 

on the Muskingum River Reach 1 to reflect a range of possible 

Muskingum River streamflows and Ohio River backwater 

conditions. 

Backwater Modeling Solution

To reflect possible backwater conditions from the Ohio 

River on the Muskingum River, selected Ohio River water 

levels were used as the downstream boundary condition for 

the Muskingum River Reach 1 hydraulic model. For the 

remainder of this report, the original water-surface profiles 

for the Muskingum River determined using slope conveyance 

(normal-depth) as the downstream boundary condition will be 

referred to as modeling scenario A, and profiles determined 

using selected Ohio River water levels as the downstream 

boundary condition will be referred to as modeling scenario 

B. For scenario B, 228 water-surface profiles were determined 

by using 19 Ohio River water-surface elevations ranging from 

584.1 to 620.1 ft (equal to Ohio River stages 18.0 to 54.0 ft) 

in 2-ft increments in combination with each of the 12 Muskingum River discharges listed in table 5.

Backwater Mapping Solution

Mapping floodplain boundaries corresponding to each 

of the 228 scenario B profiles was cost prohibitive; however, 

a method was devised to deliver information on approximate floodplain boundaries on the Muskingum River during 

backwater conditions. Scenario B profiles for Reach 1 of the 

Muskingum River were split into 13 geographic areas (fig. 5). 

Scenario A profiles that most closely matched the Scenario 

B profiles were determined for each area. Thus, a continuous 

floodplain boundary made from various segments (geographic 

areas) of Scenario A could be displayed that approximated 

each profile from the Scenario B profiles. An example showing 

a selected Scenario B profile, two selected Scenario A profiles, 

and the approximated water-surface profile for two mapping 

area segments is shown in fig. 6.

Backwater Mapping Limitations and Error 

Analyses

The approximations of backwater-condition floodplain 

boundaries were limited to the highest mapped stage (stage 

48.0) available from Scenario A profiles. As a result, approximated stage 48 floodplain boundaries may underrepresent the 

expected flooding extents due to backwater conditions from 

the Ohio River. For the following error analyses, flooding 

extents exceeding the stage 48.0 floodplain boundaries from 

Scenario A will be referred to as “48.0+”. 

The 48.0+ designation is most prevalent under two situations. The first situation is along the most downstream end of 

the Muskingum River with extreme stages on the Ohio River. 

Backwater effects (as expected) are most pronounced at the 

downstream end of a contributing stream and then dissipate in 

the upstream direction. For area 1 (fig. 5), the 48.0+ designation is used for all Scenario B profiles above stage 42.0 on 

the Ohio River. Stage 40 on the Ohio River at Marietta and 

(by coincidence) stage 40 on the Muskingum River at Beverly is deemed Major Flood stage (NWS, 2012). The second 

situation is for the upper end of Reach 1 of the Muskingum 

River with extreme stages on both the Ohio and Muskingum 

Rivers. In area 13 (fig. 5), the 48.0+ designation is used for 

only the Scenario B profiles with a stage 48.0 on the Muskingum River and stages 40.0 and above on the Ohio River. The 

discharge associated with a stage of 48.0 for the Muskingum 

River at Beverly (table 5) is more than the 0.2-percent chance 

annual-exceedance probabilities estimate of 185,000 ft3

/sec 

(USGS, 2012).

The largest differences in water-surface elevations 

between the approximated water-surface profiles and Scenario 

B profiles are at the cross sections that bound each of the 13 

segmented areas (fig. 5). For Scenario B profiles where the 

48.0+ designation occurs, the largest differences range from 

-12.5 ft in area 1, decreasing to -0.8 ft in area 13. This is not 

unexpected, as backwater is less pronounced in the upstream 

direction and the maximum Scenario A profile available for 

comparison was limited to a stage of 48.0.

For the flooding extents that are not 48.0+ designations, the differences in water-surface elevations between the 

approximated water-surface profiles and Scenario B profiles 

ranged from -1.2 to 4.0 ft, with a median value of 0.0 ft; more 

than 95 percent are within 2 ft. This range is equal to the base 

mapping contour interval and the mapped-stage interval.
Hydraulic Modeling Component 13

!

!

!

!

!

!

River

Muskingum

Marietta

Area 1

Area 2

Area 7

Area 12

Area 13

Oak Grove

Devola

Lowell

Coal

Run

Beverly

Area 11

Area 10 Area 9

Area 8

Area 6

Area 5

Area 4

Area 3

MORGAN

NOBLE

WASHINGTON

WEST

VIRGINIA

Lock and Dam

Number 3

Lock and Dam

Number 2

Lock and Dam

Number 4

Ohio

River

2,225,000 2,250,000

525,000 550,000 575,000

Base from U.S. Geological Survey digital data, variously scaled, 2007

State Plane Coordinate System (feet), Ohio South, NAD83 Datum

EXPLANATION

County boundaries

Locks and dams

Rivers

! Cities

0 1 2 3 MILES

0 1 2 3 KILOMETERS

Map area

OHIO

Figure 5. Geographic areas for mapping of the Muskingum River from Beverly to Marietta.
14 Flood-Inundation Maps for a Flood-Warning System for Selected Communities along the Lower Muskingum River and Ohio River 618 616 614 612 610 608 60635,000 40,000 45,000 50,000 55,000 60,000 65,000 70,000

Elevation, in feet NAVD88

Stationing, in feet above the mouth of the Muskingum River

Area 6 Area 7

EXPLANATION

Aprroximated water-surface profile constructed from Scenario A 

water-surface profiles

Segmented area for floodplain-boundary mapping for Muskingum River 

Reach 1

Scenario A water-surface profile of the Muskingum River for stage 36.0 

feet at Beverly, Ohio

Scenario A water-surface profile of the Muskingum River for stage 38.0 feet at 

Beverly, Ohio

Scenario B water-surface profile of the Muskingum River for stage 34.0 feet at 

Beverly, Ohio using 604.1feet as a known-water-surface elevation

Figure 6. Plot showing two water-surface profiles from Scenario A, one water-surface profile from Scenario B, and the approximated water-surface profile constructed from normal-depth profile segments for two mapping area segments for the Muskingum River.
Summary 15

Flood-Inundation Maps Component

Flood-inundation areas were initially mapped with 

HEC–GeoRAS software (USACE, 2002a). USGS personnel 

modified the HEC–GeoRAS results to ensure a logical transition of the flood-inundation boundary between modeled cross 

sections based on elevation contour data for the land surface 

(Whitehead and Ostheimer, 2009). Flood-inundation boundaries for the 12 selected profiles at both McConnelsville and 

Beverly with normal-depth boundary conditions were then 

overlain onto digital orthophotos from the Ohio Geographically Referenced Information Program (Ohio Geographically 

Referenced Information Program, 2007). 

Flood-Inundation Map Delivery

The current study documentation is available online at the 

U.S. Geological Survey Publications Warehouse (http://pubs.

usgs.gov/sir/2014/5195). In addition, a Flood Inundation Mapping Science Web site (USGS, 2014b) has been established to 

make USGS flood-inundation study information available to 

the public. That site links to a mapping application that presents map libraries and provides detailed information on flood 

extents and depths for modeled sites. The mapping application enables the production of customized flood-inundation 

maps from the map library for the Ohio River near Marietta, 

Muskingum River at Beverly, and Muskingum River at 

McConnelsville, Ohio. The estimated flood-inundation maps 

are displayed in sufficient detail so that preparations for flooding and decisions for emergency response can be performed 

efficiently. Depending on the flood magnitude, roadways are 

shown as shaded (inundated and likely impassable) or not 

shaded (dry and passable) to facilitate emergency planning 

and use. A shaded building should not be interpreted to mean 

that the structure is completely submerged; rather, shading 

indicates that bare earth surfaces in the vicinity of the building 

are inundated. In these instances, the water depth (as indicated 

in the mapping application by holding the cursor over an inundated area) near the building would be an estimate of the water 

level inside the structure, unless flood-proofing measures had 

been implemented.

Disclaimer for Flood-Inundation Maps

The flood-inundation maps should not be used for navigation, regulatory, permitting, or other legal purposes. The 

USGS provides these maps “as-is” for a quick reference, 

emergency planning tool but assumes no legal liability or 

responsibility resulting from the use of this information.

Uncertainties and Limitations Regarding Use of 

Flood-Inundation Maps

Although the flood-inundation maps represent the boundaries of inundated areas with a distinct line, some uncertainty 

is associated with these maps. The flood boundaries shown 

were estimated based on water stages and streamflows at 

selected USGS streamgages. Water-surface elevations along 

the stream reaches were estimated by steady-state hydraulic 

modeling, assuming unobstructed flow, and using streamflows and hydrologic conditions anticipated at the USGS 

streamgage(s). The hydraulic model reflects the land-cover 

characteristics and any bridge, dam, levee, or other hydraulic 

structures existing as of June 2014. Unique meteorological 

factors (timing and distribution of precipitation) may cause 

actual streamflows along the modeled reach to vary from those 

assumed during a flood, which may lead to deviations in the 

water-surface elevations and inundation boundaries shown. 

Additional areas may be flooded due to unanticipated conditions such as: changes in the streambed elevation or roughness, backwater into major tributaries along a main stem river, 

or backwater from localized debris or ice jams. The accuracy 

of the floodwater extent portrayed on these maps will vary 

with the accuracy of the digital elevation model used to simulate the land surface. Additional uncertainties and limitations 

pertinent to this study may be described elsewhere in this 

report.

If this series of flood-inundation maps will be used with 

NWS river forecasts, the user should be aware of additional 

uncertainties that may be inherent or factored into NWS forecast procedures. The NWS uses forecast models to estimate 

the quantity and timing of water flowing through selected 

stream reaches in the United States. These forecast models (1) 

estimate the amount of runoff generated by precipitation and 

snowmelt, (2) simulate the movement of floodwater as it proceeds downstream, and (3) predict the flow and stage (watersurface elevation) for the stream at a given location (AHPS 

forecast point) throughout the forecast period (every 6 hours 

and 3 to 5 days out in many locations). For more information 

on AHPS forecasts, please see: http://water.weather.gov/ahps/

pcpn_and_river_forecasting.pdf. 

Summary

Components of a flood-warning system were updated 

for selected reaches of the Muskingum and Ohio Rivers in 

Morgan and Washington Counties, Ohio, by the U.S. Geological Survey (USGS), in cooperation with the Muskingum 

Watershed Conservancy District and City of Marietta, Ohio. 

The updates include the addition of two new streamgages to 

the existing USGS streamgage network and delineation of 

flood-inundation boundaries that correspond to selected flood 

stages. The two new streamgages are the Muskingum River at 

Beverly, Ohio (03150500) and the Ohio River above Sardis, 
16 Flood-Inundation Maps for a Flood-Warning System for Selected Communities along the Lower Muskingum River and Ohio River

Ohio (03114306). Data from the streamgages could be used by 

the National Weather Service (NWS) to improve peak-stage 

predictions for the Ohio and Muskingum Rivers.

Water-surface profiles were estimated by use of steadystate step-backwater models, and corresponding flood-inundation areal boundaries were delineated for up to 12 stages at the 

following U.S. Geological Survey (USGS) streamgages: Ohio 

River at Marietta, Ohio (03150700), Muskingum River at Beverly, Ohio (03150500), and Muskingum River at McConnelsville, Ohio (03150000). The flood-inundation boundaries were 

overlain on digital orthophotos, and the profiles correspond 

to streamflows ranging from the 10- to 0.2-percent chance 

annual-exceedance probabilities for each of the 3 streamgages. 

The effects of backwater from the Ohio River were also modeled, and approximate flood boundaries are shown in segments 

based upon the normal-depth flood boundaries.

Real-time streamgage information, flood-forecast predictions, and flood-inundation mapping corresponding to flood 

forecasts can be accessed on Web sites hosted by the USGS 

and the NWS. It is anticipated that the increased amount and 

availability of publically accessible streamflow data, along 

with enhanced flood-prediction capability, will improve the 

ability of public and emergency-management officials to 

assess flood conditions, take appropriate steps to protect life 

and property, and reduce flood damage.

References Cited

Dewberry, 2012, National Enhanced Elevation Assessment: Fairfax, Va., 84 p., accessed July 9, 2013, at http://

www.dewberry.com/files/pdf/NEEA_Final%20Report_

Revised%203.29.12.pdf.

Franz, D.D., Melching, C.S., 1997, Full Equations (FEQ) 

model for the solution of the full, dynamic equations of 

motion for one-dimensional unsteady flow in open channels and through control structures: U.S. Geological Survey 

Water-Resources Investigations Report 96-4240, 258 p.

Hittle, C.D., and Ruby, A.T., III, 2008, Bathymetric surveys of 

Lake Arthur and Raccoon Lake, Pennsylvania, June 2007: 

U.S. Geological Survey Data Series 357, p. 3, 4, 9.

National Weather Service, 2012, Advanced Hydrologic 

Prediction Service, accessed May 29, 2012, at http://water.

weather.gov/ahps2/hydrograph.php?wfo=rlx&gage=mtao1.

Ohio Department of Transportation, 2014, ODOT’s VRS TRK 

Network, accessed June 25, 2014, at http://www.dot.state.

oh.us/Divisions/Engineering/CaddMapping/Aerial/Pages/

VRSRTK.aspx. 

Ohio Geographically Referenced Information Program, 2007, 

Ohio Statewide Imagery Program, accessed May 29, 2012, 

at http://gis3.oit.ohio.gov/geodata/. 

Reson, Inc., 2005, NaviSound 200/400 users guide: 

Navisound TM 100, 200 & 400 series operator’s manual, 

version 4.01, 177 p.

Rydlund, P.H., Jr., and Densmore, B.K., 2012, Methods of 

practice and guidelines for using survey-grade global navigation satellite systems (GNSS) to establish vertical datum 

in the United States Geological Survey: U.S. Geological 

Survey Techniques and Methods, book 11, chap. D1, 

102 p. with appendixes, accessed August 15, 2014, at 

http://pubs.usgs.gov/tm/11d1/.

U.S. Army Corps of Engineers–Hydrologic Engineering Center, 2002a, HEC–GeoRAS, accessed July 29, 2011, at http://

www.hec.usace.army.mil/software/hec-georas/.

U.S. Army Corps of Engineers, 2002b, Engineering and 

design—Hydrographic surveying: Washington, D.C., 

manual no. 1110 2–1003, 510 p.

U.S. Army Corps of Engineers–Hydrologic Engineering Center, 2010, HEC–RAS River Analysis System, user’s manual, 

ver. 4.1 [variously paged].

U.S. Census Bureau, 2012a, State & County QuickFacts, 

Morgan County, Ohio, Population, 2010, accessed on 

March 28, 2012, at http://quickfacts.census.gov/qfd/

states/39/39115.html.

U.S. Census Bureau, 2012b, State & County QuickFacts, 

Washington County, Ohio, Population, 2010, accessed 

on March 28, 2012, at http://quickfacts.census.gov/qfd/

states/39/39167.html.

U.S. Census Bureau, 2012c, State & County QuickFacts, 

Marietta (city), Ohio, Population, 2010, accessed on 

March 28, 2012, at http://quickfacts.census.gov/qfd/

states/39/3947628.html.

U.S. Geological Survey, 2012, Streamstats application, 

accessed on March 28, 2012, at http://water.usgs.gov/osw/

streamstats/ohio.html.

U.S. Geological Survey, 2014a, U.S. Geological Survey Flood 

Inundation Mapping Science, Technical Tools, accessed on 

March 28, 2014, at http://water.usgs.gov/osw/

flood_inundation/toolbox/librarytools.html.

U.S. Geological Survey, 2014b, USGS Flood Inundation Mapping Science: U.S. Geological Survey, accessed August 1, 

2014, at http://water.usgs.gov/osw/flood_inundation.

Whitehead, M.T., and Ostheimer, C.J., 2009, Development 

of a flood warning system and flood-inundation mapping 

for the Blanchard River in Findlay, Ohio: U.S. Geological 

Survey Scientific Investigations Report 2008–5234, 9 p.

Whitehead and Ostheimer—Flood-Inundation Maps for a Flood-Warning System for Selected Communities along the Lower Muskingum River and Ohio River— SIR 2014–5195

ISSN 2328-0328 (online)

http://dx.doi.org/10.3133/sir20145195