U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2010–5174

Prepared in cooperation with

Frederick County, Maryland 

and the

City of Frederick, Maryland

Water Volume and Sediment Accumulation 

in Lake Linganore, Frederick County,

Maryland, 2009
Cover.  1995 aerial photograph of the Lake Linganore study area, Frederick County, Maryland, from the U.S. Department of Agriculture

(USDA) National Agriculture Imagery Program (NAIP).
Water Volume and Sediment Accumulation 

in Lake Linganore, Frederick County, 

Maryland, 2009

By Andrew J. Sekellick and William S.L. Banks

Scientific Investigations Report 2010–5174

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with 

Frederick County, Maryland

and the 

City of Frederick, Maryland 
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2010

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Suggested citation:

Sekellick, A.J., and Banks, W.S.L., 2010, Water volume and sediment accumulation in Lake Linganore, Frederick 

County, Maryland, 2009: U.S. Geological Survey Scientific Investigations Report 2010–5174, 14 p.

ISBN 978-1-4113-2968-3
iii

Contents

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

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

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

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

Methods...........................................................................................................................................................2

Data Collection......................................................................................................................................5

Data Processing....................................................................................................................................7

Quality Control.......................................................................................................................................8

Water Volume.................................................................................................................................................9

Sediment Accumulation..............................................................................................................................10

Summary........................................................................................................................................................13

Acknowledgments.......................................................................................................................................14

References Cited..........................................................................................................................................14

Figures

1–2. Maps showing—

1a. Location of Linganore Creek watershed, Frederick County, Maryland......................3

1b. Location of Lake Linganore study area, Frederick County, Maryland ........................4

2. Planned survey lines with 100-foot transect spacing and qualitycontrol lines with 500-foot transect spacing, Lake Linganore, 

Maryland, 2009 .....................................................................................................................5

3–4. Photographs showing—

3. Placement of echosounding equipment and global positioning system 

mounted on the bow of the work boat .............................................................................6

4. Work boat and data-collection and processing equipment.........................................6

5. Map showing collected data points, target data points, and qualityassurance data points, Lake Linganore, Maryland, 2009.......................................................7

6. Graph showing raw data and non-bottom reflectors, Lake Linganore, 

Maryland, 2009 ..............................................................................................................................8

7. Map showing bathymetric contours of Lake Linganore, Maryland, 2009.........................10

8. Graph showing elevation-capacity curve for Lake Linganore, 

Maryland, 2009 ............................................................................................................................11

9–10. Maps showing—

9. Study sections of Lake Linganore, Maryland, 2009......................................................11

10. Sediment accretion and scour in Lake Linganore, Maryland, 2009..........................12

11. Diagram showing generalized cross section of Lake Linganore from 

section 1, Lake Linganore, Maryland, 2009 ............................................................................13
iv

Conversion Factors and Datums

Multiply By To obtain

Length

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2)

acre 0.004047 square kilometer (km2)

square mile (mi2) 2.590 square kilometer (km2)

Volume

gallon (gal) 3.785 liter (L)

gallon (gal) 0.003785 cubic meter (m3)

million gallons (Mgal) 3,785 cubic meter (m3)

acre-foot (acre-ft) 1,233 cubic meter (m3)

cubic yard (yd3) 0.7646 cubic meter (m3)

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

 °C = (°F - 32) / 1.8

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

(NAVD 88).

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

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

Tables

1. Area/capacity from Triangulated Irregular Network model of bathymetric 

data collected from Lake Linganore, Frederick County, Maryland, 2009 ............................9

2. Water-storage capacity, water volume, and sediment accumulation in 

Lake Linganore, Frederick County, Maryland, 2009 ..............................................................12


Water Volume and Sediment Accumulation in Lake 

Linganore, Frederick County, Maryland, 2009

By Andrew J. Sekellick and William S.L. Banks

Abstract

To assist in understanding sediment and phosphorus loadings and the management of water resources, a bathymetric 

survey was conducted at Lake Linganore in Frederick County, 

Maryland in June 2009 by the U.S. Geological Survey, in 

cooperation with the City of Frederick and Frederick County, 

Maryland. Position data and water-depth data were collected 

using a survey grade echo sounder and a differentially corrected global positioning system. Data were compiled and 

edited using geographic information system software. A threedimensional triangulated irregular network model of the lake 

bottom was created to calculate the volume of stored water in 

the reservoir. Large-scale topographic maps of the valley prior 

to inundation in 1972 were provided by the City of Frederick 

and digitized. The two surfaces were compared and a sediment volume was calculated. Cartographic representations of 

both water depth and sediment accumulation were produced 

along with an area/capacity table. An accuracy assessment was 

completed on the resulting bathymetric model. Vertical accuracy at the 95-percent confidence level for the collected data, 

the bathymetric surface model, and the bathymetric contour 

map was calculated to be 0.95 feet, 1.53 feet, and 3.63 feet, 

respectively. 

The water storage volume of Lake Linganore was 

calculated to be 1,860 acre-feet at full pool elevation. Water 

volume in the reservoir has decreased by 350 acre-feet (about 

16 percent) in the 37 years since the dam was constructed. The 

total calculated volume of sediment deposited in the lake since 

1972 is 313 acre-feet. This represents an average rate of sediment accumulation of 8.5 acre-feet per year since Linganore 

Creek was impounded. A sectional analysis of sediment 

distribution indicates that the most upstream third of Lake 

Linganore contains the largest volume of sediment whereas 

the section closest to the dam contains the largest amount of 

water. In comparison to other Maryland Piedmont reservoirs, 

Lake Linganore was found to have one of the lowest sedimentation rates at 0.26 cubic yards per year per acre of drainage 

area. Sedimentation rates in other comparable Maryland 

reservoirs were Prettyboy Reservoir (filling at a rate of 2.26 

cubic yards per year per acre), Loch Raven Reservoir (filling 

at a rate of 0.88 cubic yards per year per acre) and Piney Run 

Reservoir (filling at a negligible rate).

Introduction

The U.S. Environmental Protection Agency has identified the Lower Monocacy River, a tributary to the Chesapeake 

Bay, as impaired by sediment and nutrients, and has imposed 

a sediment and phosphorus Total Maximum Daily Load 

(TMDL) (Maryland Department of the Environment, 2002). 

Linganore Creek is a tributary of the Lower Monocacy River. 

Lake Linganore, an impoundment on Linganore Creek, 

provides water to the City of Frederick and Frederick County, 

Maryland. To meet the TMDL regulatory requirement, and 

assist the City of Frederick and Frederick County, Maryland 

in mitigating sediment and phosphorus loadings and manage 

their water resources, it is necessary to understand the amount 

of water impounded in Lake Linganore and to accurately 

quantify the volume of sediment behind the dam to allow the 

City and County to meet their water-use needs. To address 

these issues, the City of Frederick and Frederick County asked 

the U.S. Geological Survey (USGS) to investigate water volume and sediment accumulation in the lake. 

As a result of sedimentation problems in the contributing waters, the capacity of Lake Linganore has decreased 

(Frederick County, Maryland, 2006). In order to effectively 

and efficiently manage water resources, the City of Frederick 

and Frederick County have twice estimated the water capacity 

of Lake Linganore. A 1980 report provided an initial estimate 

of water volume for the reservoir of 2,710 acre-ft (acre-feet) 

as constructed (Zeigler, 1980). The parameters of this first 

survey are not well documented and the extent of the reservoir 

during the survey is not known. In 2002, the City of Frederick 

and Fredrick County hired a contractor to produce a siltation 

and capacity report that determined lake volume was 2,240 

acre-ft in 1999. This same report estimated a pre-reservoir 

water capacity of 2,560 acre-ft based on 2-ft (foot) contour 

intervals surveyed prior to dam construction. This corresponds 

to a volume loss of 320 acre-ft (12.5 percent) (Whitman, 

Requardt & Associates, 2002). The methods and extents of the 

reservoir reported in Zeigler (1980) and Whitman, Requardt 

& Associates (2002) are not the same as those used in this 

report. Direct comparisons between this study and historical studies should not be made. All calculations of potential 

water volume loss and sediment accumulation in the current 

study are based on the methods described herein and compare 
2 Water Volume and Sediment Accumulation in Lake Linganore, Frederick County, Maryland, 2009

current measured volume to theoretical volumes as calculated 

from 1972 topography between the dam and Boyers Mill Road 

bridge.

Purpose and Scope

This report describes the water-storage capacity and 

sediment accumulation in Lake Linganore in Frederick 

County, Maryland from 1972 through 2009. This report also 

describes methods used to collect and process the bathymetric 

data necessary to determine the elevation of the lake bottom 

and compute the water volume of the reservoir. In addition, 

the report describes an accuracy assessment of the collected 

environmental dataset and the methods described above.

Description of Study Area

Lake Linganore is located on Linganore Creek in central 

Frederick County, Maryland, 35 miles west of Baltimore, 

Maryland (fig. 1a). Linganore Creek drains part of the 

Piedmont Physiographic Province. The area is characterized 

by rolling hills and moderately to deeply incised, well-drained 

valleys with altitudes ranging from sea level to more than 900 

ft above sea level (DiLisio, 1983). The lake was created in 

1972 by construction of an earthen dam on Linganore Creek. 

The impoundment, as designed, extends from the dam to a 

point 2 mi (miles) upstream. For the purposes of this study, the 

extent of the reservoir is limited to the part of the lake downstream of Boyers Mill Road. Therefore, water volume calculations and areas of sediment accretion and scour are limited to 

this area (fig. 1b).

The lake was originally constructed for recreation 

purposes for the private community of Lake Linganore at 

Eaglehead. The reservoir currently serves as one part of the 

City of Frederick’s water supply and provides part of the water 

supply for Frederick County. In 2009, the City of Frederick 

was permitted to withdraw 6.0 Mgal/d (million gallons per 

day), while keeping a minimum of 4.5 Mgal/d passing over 

the dam for ecological health downstream in Linganore 

Creek (Frederick County, Maryland, 2006). The County is 

permitted to withdraw an additional 1.2 Mgal/d as long as 

the lake’s pool elevation is at least 308 ft, the elevation of the 

spillway (Michael Marschner, Director of Public Utilities and 

Solid Waste, Frederick County, Maryland, written commun., 

February 24, 2010).

Precipitation in the basin averages 40.64 inches per 

year. Temperatures range from a July mean of 77.9 degrees 

Fahrenheit to a December mean of 33.3 degrees Fahrenheit 

(National Oceanic and Atmospheric Administration, 2006). 

Land use in the 81.1-mi2 (square mile) watershed is 16 percent 

developed, 56 percent agriculture, and 28 percent forested and 

other land uses (Maryland Department of the Environment, 

2002). Frederick County is within commuting distance to 

the Washington, D.C. and Baltimore, Maryland metropolitan areas and has experienced population growth in the last 

decade. During the 1990s, the population of Frederick County 

increased by 30 percent (45,000 people) (U.S. Census Bureau, 

2009). Land-use conversion and the expansion of impervious 

surfaces can cause increases in stormwater runoff, streamflow, 

erosion, and sediment and phosphorus loadings, such as those 

that have had a significant impact on the water quality of the 

Chesapeake Bay and its tributaries (Gellis and others, 2009).

Methods

The commercial hydrographic survey software package 

HYPACK was used for planning, data acquisition, and data 

management before, during, and after the survey (HYPACK, 

2008). Survey lines (pre-planned lines designed to guide datacollection operations) were created at 100-ft intervals along 

the long (east-west) axis of the lake. The transect spacing was 

computed to optimize data coverage and accuracy and resulted 

in a data-collection line spacing of approximately 1 percent 

of the longitudinal distance of the lake for optimum coverage 

detail (Wilson and Richards, 2006) (fig. 2). Using this transect 

spacing, 12.7 mi of data-collection lines were planned for 

the survey. In order to maximize accuracy, survey lines were 

oriented perpendicular to the shoreline. As the geometry of 

the lake changed, the orientation of survey lines was rotated 

to best maintain an optimum perpendicular relation to the 

shoreline. 

In addition to the survey lines described, a separate set 

of quality-assurance transect lines were planned to provide 

independent measurements of precision and bias. These lines, 

oriented at approximately a 45-degree angle to the survey 

lines, provided an independent measurement of depth on 

the basis of differing field conditions at points where they 

intersected with the environmental survey lines. Sixteen of 

these quality-assurance lines were spaced at 500-ft intervals 

between Boyers Mill Road and the dam, and provided 

approximately 90 coincidental points (fig. 2). Once spacing 

and orientation of the survey lines were planned, both the 

environmental transects (100-ft spacing) and the qualityassurance transects (500-ft spacing) were imported into the 

HYPACK software to guide the field crew during data collection. The horizontal projection of the survey was Universal 

Transverse Mercator Zone 18 North, North American Datum 

of 1983 (UTM, NAD83) and the vertical control datum was 

North American Vertical Datum of 1988 (NAVD 88). These 

projections were used for both the Geographic Information 

System (GIS) and HYPACK platforms.
Methods 3

Figure 1a. Location of Linganore Creek watershed, Frederick County, Maryland.
4 Water Volume and Sediment Accumulation in Lake Linganore, Frederick County, Maryland, 2009

Figure 1b. Location of Lake Linganore study area, Frederick County, Maryland.
Methods 5

Data Collection

Bathymetric data were collected using an Ocean Data 

Equipment Corporation Bathy-500MF Survey Echo Sounder 

with a 200 KHz (kilohertz) transducer with a beam width of 

3 degrees. Echo sounding transducers emit ultrasonic energy 

that is reflected and refracted off the lake bottom. A portion 

of this signal is returned to a receiver aboard the transmitting 

vessel and recorded as a two-way traveltime. This process 

allows depth calculations based on a known velocity of sound 

in water. Because water temperature affects this velocity, 

water temperature was measured and recorded to assist in 

calibrating the transducer. Depth calibration was performed 

twice daily (each morning and at mid day) by placing a metal 

plate at a known depth below the transducer at different 

locations in the lake. The depth on the plate was noted and 

a temperature-adjusted measurement of the speed of sound 

was used to adjust the measured depth to match the known 

depth of the metal plate. Positional data was collected using 

a Trimble AgGPS differentially corrected global positioning 

system (GPS) receiver that provided latitude and longitude 

with a horizontal accuracy of at least 3.28 ft as stated by the 

manufacturer (Trimble Navigation Limited, 1999). Survey 

transects were redone if differential signal was lost during 

data collection. The GPS receiver was coincidental (within 1 

ft) with the location of the bathymetric transducer—both were 

located on the bow of the boat (fig. 3). 

Data were collected on June 11, 15, 17, and 23, 2009. All 

data-collection platforms were mounted aboard an aluminumhulled, dual pontoon work boat with an outboard motor 

(fig. 4). Work crews consisted of a boat operator and two 

members of the USGS Maryland-Delaware-District of 

Columbia Water Science Center. The water elevation at the 

spillway was recorded each day prior to data collection and at 

least one other time during each day. Calibration of the echo 

sounder was performed as previously described prior to data 

collection and at midday. 

Input data from all sensors and navigation equipment 

were processed by HYPACK using an onboard laptop computer. Depth and GPS coordinates were displayed in real time 

Figure 2. Planned survey lines with 100-foot transect spacing and quality-control lines with 500-foot transect spacing, Lake 

Linganore, Maryland, 2009.
6 Water Volume and Sediment Accumulation in Lake Linganore, Frederick County, Maryland, 2009

Figure 3. Placement of echo-sounding equipment and global positioning system mounted on 

the bow of the work boat. [Photograph by William Banks, U.S. Geological Survey, 2009.]

Figure 4. Work boat and data-collection and processing equipment. [Photograph by William 

Banks, U.S. Geological Survey, 2009.]
Methods 7

through a graphical user interface to assist in navigation of the 

boat. This allowed the boat operator and scientists to view the 

current location of the boat in relation to the predetermined 

survey lines. Data were collected at a rate of 5 data points per 

second. The average boat speed was approximately 3 knots, 

with maximum speeds as high as 5 knots. At these speeds and 

data acquisition rates, a data point was generated approximately every 1 ft of linear distance traveled on each transect, 

producing a dataset of 64,075 data points across the study 

area. No data were collected in areas of the lake where water 

depth was not sufficient for boat operations 

(fig. 5). Additional target data points were collected at 

locations where navigation to projected plan lines was not 

possible due to safety concerns (dam spillway) or limited 

maneuverability (cove on the north-central part of the lake 

in figure 5). In these areas, target data points were collected 

to supplement survey data. Target data points involved crew 

members taking depth measurements by hand and recording 

the GPS location manually (fig. 5). All points and their associated depths were entered and backed up each day on the 

USGS computer network.

Data Processing

In 1971, 16 large-scale topographic maps were produced 

for the City of Frederick showing parts of the Linganore 

Creek watershed. The maps represent the part of the basin that 

was planned to be inundated after construction of Linganore 

dam and the subsequent filling of Lake Linganore. The maps 

were constructed using 2-ft contour intervals derived from 

field surveys in 1971 (Michael Marschner, Director of Public 

Utilities and Solid Waste, Frederick County, Maryland, written 

commun., June 10, 2009). For the current study, the City of 

Frederick provided digital copies of the maps at a 1:600 scale. 

These maps provided a reference surface that was used to 

calculate sediment accumulation in the study area. 

Scaled images of the maps were imported into a GIS and 

were geo-referenced to properly display the spatial data. This 

allowed the topographic surface of the valley prior to inundation to be created. To calculate the water volume of the reservoir, a variety of models and interpolations were considered, 

including an inverse distance-weighted model, a spline model, 

and kriging techniques. A Triangulated Irregular Network 

Figure 5. Collected data points, target data points, and quality-assurance data points, Lake Linganore, Maryland, 2009.
8 Water Volume and Sediment Accumulation in Lake Linganore, Frederick County, Maryland, 2009

(TIN) model was ultimately chosen on the basis of results 

achieved by Wilson and Richards (2006), Soler-López (2008), 

and Kress and others (2005). TIN models have been used to 

accurately represent reservoir and lake-bottom surfaces for 

the purpose of determining both water and sediment volume 

(Wilson and Richards, 2006). The TIN model chosen for this 

study was created using the three-dimensional analysis tool 

in ArcGIS (Environmental Systems Research Institute Inc., 

2000). Models created using a TIN are built by connecting a 

set of points to create a network of triangles that form a threedimensional vector-based surface. 

Reservoir water-volume calculations are dependent on the 

accurate representation of a shoreline that is consistent with 

the elevation of the top of the dam at the spillway. A shoreline 

was digitized using 1-m (meter) orthophotos collected by the 

U.S. Department of Agriculture (USDA) National Agriculture 

Imagery Program (NAIP) in 2005. Additional points were 

collected during the bathymetric survey to help ensure the 

digitized shoreline corresponded to a water elevation of 308 

ft (the spillway elevation) and to help define the shoreline in 

areas where shadows, trees, or other obstructions prevented 

the use of the NAIP data. Using these additional points and the 

NAIP orthophotos, a final shoreline was created for use in the 

current study.

Once data collection was complete, the raw data were 

examined using HYPACK to identify spurious reflections 

created by submerged objects, including fish, tree limbs, and 

other non-bottom reflectors. These artifacts were easily identified by viewing the raw data as a function of linear distance 

traveled. Non-bottom reflectors were visible as spikes and 

floating, non-linear data points (fig. 6). These false reflections 

were removed, and the remaining data were normalized to the 

spillway elevation of 308 ft and exported as a table containing 

x, y, and z positional values. Normalization on days when lake 

elevation was less than 308 ft was performed by adding the 

difference between the full and recorded spillway elevation. 

On days when the lake elevation exceeded 308 ft, the difference was subtracted from the recorded values. Edited data 

were imported to ArcGIS and a TIN model was created. These 

data were then constrained to the calculated shoreline. On the 

few occasions where data points plotted beyond the calculated 

shoreline, the data points were removed. Cartographically 

smoothed contours of the lake bottom were then created from 

the TIN model for map production and visualization purposes. 

Water and sediment volumes were calculated from the TIN 

model, rather than the smoothed contours. Another TIN 

model, created from the digitized 1971 topography, was used 

in conjunction with the lake-bottom TIN model to calculate 

sediment volume. A cartographic surface also was created 

showing areas of sediment deposition and scouring.

Quality Control

Vertical accuracy was determined by use of guidelines 

from the National Standard for Spatial Data Accuracy 

(NSSDA), which require an independent quality-assurance and 

quality-control dataset (Federal Geographic Data Committee, 

1998). Quality-assurance data points were compared to coincident data points from the environmental survey. Points were 

considered to be coincidental if they were less than 0.5 ft apart 

in horizontal distance. To determine the precision in this measurement, the square root of the mean of the squared residuals 

(or RMSE) was calculated using equation (1) below. 

 RMSE Z Z n z data check i i = − [ ( ∑ ) / ] 2 (1)

where

	 RMSEz = root mean square error of the z, or vertical 

component;

	 Zdatai = the coordinate of the i

th check point in the 

environmental dataset;

Zchecki = the coordinate of the i

th check point in the 

quality-assurance dataset; and

n = the number of coincidental points.

When compared to the environmental dataset, there 

were 90 points measuring depth at coincidental locations. 

Absolute differences between the two datasets ranged from 

0.0 ft to 1.24 ft. Differences tended to be negatively biased 

as depth increased. The median depth of the environmental 

data at coincidental quality-control locations was 13.71 ft. 

Using equation (1) above, a RMSEz of 0.11 ft was calculated 

for depths less than the median, whereas a RMSEz of 0.61 

ft was calculated for depths greater than the median. An 

overall RMSEz of 0.49 ft was calculated for the entire dataset. According to the NSSDA guidelines, a factor of 1.96 is 

multiplied by the RMSEz to determine vertical accuracy at 

the 95-percent confidence interval. Thus, depths less than the 

median have a vertical accuracy of 0.22 ft, whereas depths 

Figure 6. Raw data and non-bottom reflectors, Lake Linganore, 

Maryland, 2009.
Water Volume 9

greater than the median have a vertical accuracy of 1.20 ft at 

the 95-percent confidence interval. Overall, this procedure 

indicates that vertical data collected for this study have an 

accuracy of plus or minus 0.95 ft. The vertical accuracies of 

the bathymetric surface model and the bathymetric contour 

map were 1.53 ft and 3.62 ft, respectively, at the 95-percent 

confidence interval using the NSSDA guidelines.

A latency test can be used to determine the delay between 

the time when positioning data are received and the time 

attributed to the signal leaving the echo sounder. This delay 

is determined by moving the test vehicle along reciprocal 

survey lines over a steep bank—in this case, the upstream 

face of the dam. Latency usually results in a negative, alongtrack displacement of the depth value. Surveys performed at 

slow speeds generally have small displacement values (U.S. 

Army Corps of Engineers, 2002). Latency in the current study, 

according to the parameters stated above, was 0.45 seconds. 

At an average survey speed of 3.0 knots (5.06 feet per second), 

the resulting offset was 2.3 ft. This offset was compared to the 

3.28-ft horizontal position accuracy given by the manufacturer 

(Trimble Navigation Limited, 1999). This indicates that horizontal error caused by the time delay between transmission 

and reception of depth data would be less than the horizontal 

accuracy of the GPS. Given the slow velocity of the boat, the 

relatively shallow depths encountered, and the accuracy of the 

positional data, no latency correction was applied.

Water Volume

The water-storage volume of Lake Linganore was calculated to be 1,860 acre-ft at full pool elevation (table 1). Full 

pool, the elevation where the water level is equal to that of 

the dam spillway, is 308 ft for Lake Linganore. Median water 

depth of the reservoir is 14.36 ft, with a maximum depth near 

the spillway of nearly 40 ft. Although obscured, the remnant 

of pre-inundation Linganore Creek bed can be seen in the data 

as a linear feature of deeper water extending from the southern 

side of Boyers Mill Road bridge, crossing the lake and following the western shore south to Coldstream Beach, continuing 

south across the lake to the southern shore where it runs west 

to the mouth of the Southern Cove, and from there following 

the center line of the lake until it reaches the north end of the 

dam (fig. 7). 

Water volume in the reservoir has decreased by at least 

350 acre-ft (about 16 percent) in the 37 years since the dam 

was constructed. This difference was calculated by subtracting 

the potential storage volume in the reservoir as measured from 

the digitized 1972 topography (2,210 acre-ft between the dam 

and Boyers Mill Road bridge) and the 2009 survey volume of 

1,860 acre-ft covering the same area. This difference corresponds to an average loss of 9.40 acre-ft per year. The areato-capacity relation from the TIN model bathymetric data for 

Lake Linganore downstream from Boyers Mill Road bridge 

is shown in table 1. The corresponding elevation-capacity 

curve for the lake is shown in figure 8. There is a decrease in 

capacity of 520 acre-ft (28 percent) for the first 4-ft drop in 

water elevation. As water elevation decreases further, capacity 

loss averages about 19 percent for every 4 ft until 292 ft, 

where the capacity loss over the last 22 ft averages 3 percent 

for every 4 ft.

In order to analyze changes in water volume, the lake was 

divided into three approximately equal-area sections. Section 

1 extends from Boyers Mill Road bridge to a point 3,100 

ft downstream, just east of the beach on Coldstream Drive. 

Section 2 lies between sections 1 and 3. Section 3 extends 

from the dam to a point 4,500 ft east of the dam 

(fig. 9). Water volume in section 1 is 410 acre-ft—a decrease 

of 28 percent from the original estimated volume of 570 acreft as calculated from the 1972 topography. Water volume in 

section 2 decreased 13 percent, from 690 acre-ft to 600 acre-ft. 

The water volume in section 3 was originally 950 acre-ft and 

was calculated to be 850 acre-ft in 2009, a decrease of 11 

percent (table 2). The ratio of current water-storage volume 

compared to the original water-storage volume for each 

section has changed. In 1972, section 1 represented 26 percent 

of the total storage, and in 2009, it represented 22 percent of 

the total storage. Section 2 was approximately unchanged at 

32 percent of total capacity, and the storage as a percent of 

total reservoir capacity of section 3 (the section nearest the 

dam) increased slightly from 43 percent in 1972 to 46 percent 

in 2009. This indicates that Lake Linganore is filling in a 

downstream direction, with infilling occurring more rapidly in 

the upstream third of the reservoir. 

Table 1. Area/capacity from Triangulated Irregular Network 

model of bathymetric data collected from Lake Linganore, 

Frederick County, Maryland, 2009.

Elevation1

(feet)

Area

(acres)

Capacity 

(acre-feet)

272 0 0.1

276 4 8.9

280 7 30.5

284 13 68.7

288 24 138

292 47 276

296 76 525

300 101 877

304 126 1,340

308 137 1,860

1

 Elevation is referenced to the North American Vertical Datum of 1988.
10 Water Volume and Sediment Accumulation in Lake Linganore, Frederick County, Maryland, 2009

Sediment Accumulation

The total calculated volume of sediment deposited in 

the lake below Boyers Mill Road bridge since 1972 is 313 

acre-ft. There is a 37 acre-ft difference between estimated 

water-volume loss and sediment-volume accumulation based 

on the calculations in the preceding section. This difference 

may be attributed to the exclusion of the water volumes in the 

vicinity of the dam and in the Southern Cove in the sediment 

calculations (fig. 10). There were no data for either of these 

features in the 1972 topography. The sediment accumulation 

corresponds to an average rate of 8.46 acre-ft per year over the 

37 years since Linganore Creek was impounded. Median sediment depth is 2.65 ft, with maximum depths reaching nearly 

20 ft (fig. 10) in selected locations along parts of the remnant 

Linganore Creek bed. Section 1, the section farthest upstream 

near the bridge on Boyers Mill Road where Linganore Creek 

opens up to the lake, has the largest amount of deposited 

sediment, with 142 acre-ft, or 45 percent of the total sediment 

accumulation in the lake since 1972. The next downstream 

section, section 2, contains 87 acre-ft of sediment and accounts 

for 28 percent of the total volume of sediment accumulation. 

The volume of sediment in section 3, the section closest to the 

dam, is nearly the same as the volume of sediment in section 2 

at 84 acre-ft, or 27 percent of the total sediment accumulation 

in the lake.

There are also areas of scour (areas where the elevation 

of the 2009 lake bottom elevation was less than the 1972 

surface elevation). These areas represent 56.7 acre-ft of water 

storage gained. Scour has occurred primarily along the lake 

margin, with areas up to 12 ft near Coldstream Beach (fig. 10). 

This may be a result of beach construction or maintenance 

activities. Outside the area near Coldstream Beach, most scour 

occurs along the shoreline in section 3 (fig. 10), often associated with private property or boat docks. These areas of scour 

near the shoreline could also be the result of using a bathymetric dataset and a pre-dam topographic surface of different 

accuracies and collection methods.

To show how sediment accretion has occurred in Lake 

Linganore, a three-dimensional cross section was developed from the TIN model (fig. 11). Sediment accretion in 

Lake Linganore has occurred preferentially in the bed of the 

inundated Linganore Creek. Although not shown in the cross 

Figure 7. Bathymetric contours of Lake Linganore, Maryland, 2009.
Sediment Accumulation 11

section, this effect is more pronounced upstream in wider areas 

of the lake where the original trace of the creek is most evident 

(fig. 10). To quantify this effect, a buffer of 20 ft was applied 

to either side of the thalweg of Linganore Creek throughout 

the study area. Once filled, this channel represents a volume 

of 25 acre-ft of sediment or 8 percent of the total accumulated 

sediment in the lake since 1972. The mean sediment depth 

along the 10,800-ft creek channel is 6.68 ft. Removal of this 

sediment would increase water-storage volume by 1.1 percent 

of the original 1972 reservoir storage capacity.

Other reservoirs in the Maryland Piedmont Physiographic 

Province have had different rates of sediment accumulation. 

Loch Raven Reservoir in Baltimore County, Maryland has 

a drainage area of 219.4 mi2, nearly 3 times larger than the 

drainage area of Lake Linganore. Most of the watershed is 

lightly wooded or has been cleared of vegetation for agricultural activities, and to support housing for the suburbs 

of Baltimore City. Loch Raven had an average sediment 

accumulation rate of 0.88 yd3 yr-1 acre-1 (cubic yards per year 

per acre) (Banks and LaMotte, 1999). By comparison, Lake 

Linganore had a sediment accumulation rate of 0.26 yd3 yr-1

acre-1. However, a potentially large amount of sediment in 

Figure 8. Elevation-capacity curve for Lake Linganore, 

Maryland, 2009.

Figure 9. Study sections of Lake Linganore, Maryland, 2009.
12 Water Volume and Sediment Accumulation in Lake Linganore, Frederick County, Maryland, 2009

Table 2. Water-storage capacity, water volume, and sediment accumulation in Lake Linganore, Frederick County, Maryland, 2009.

Section 

(locations 

shown in 

figure 9)

Surface area 

(acres)

Water 

volume at 

full-pool 

elevation 

(acre-feet)

Storage 

volume as a 

percentage 

of total 

volume

Potential 

1972 water 

volume 

(acre-feet)

Potential 

1972 storage 

volume as a 

percentage 

of total 

volume

Percent 

change of 

storage 

capacity 

between 

1972 and 2009

Sediment 

volume 

(acre-feet)

Percent of 

total 

sediment 

accumulation

1 45.6 410 22 570 26 28 142 45

2 45.7 600 32 690 31 13 87 28

3 45.7 850 46 950 43 11 84 27

Total 137 1,860 100 2,210 100 313 100

Figure 10. Sediment accretion and scour in Lake Linganore, Maryland, 2009. (Cross section A-A’ shown in figure 11.)
Summary 13

this study was not accounted for upstream of the Boyers Mill 

Road bridge. This area was not included due to the shallow 

depths encountered and the inability to access this area with 

the equipment used. This area could be examined by use of 

other methods to estimate the amount of sediment residing 

upstream of the Boyers Mill Road bridge. As is the case with 

Loch Raven Reservoir, it is possible that sediment will be 

transported further down into the reservoir in the future and 

the rate of sedimentation will increase (Ortt and others, 2000). 

Prettyboy Reservoir, in Baltimore County, Maryland, has a 

drainage area of 80 mi2 and an average sediment accumulation 

rate of 2.23 yd3 yr-1 acre-1 (Ortt and others, 2000). Piney Run 

Reservoir, located in Carroll County, Maryland, was constructed in 1974. Land use in the watershed is similar to land 

use surrounding Linganore Creek—predominantly agriculture, 

with about 20 percent developed land (Maryland Department 

of the Environment, 2002). However, Piney Run Reservoir 

has a drainage area that represents only 12 percent of Lake 

Linganore’s 81.1-mi2 watershed. A sedimentation analysis of 

Piney Run Reservoir conducted in 1989 found little evidence 

of deposition with a calculated volume loss of 0.4 percent. 

The analysis concluded that the low sediment deposition may 

have resulted from the widespread use of no-till farming in the 

small watershed (Maryland Department of the Environment, 

1989).

Although Piney Run Reservoir and Lake Linganore have 

similar land uses within their respective watersheds, the much 

smaller Piney Run watershed may contribute to lower sedimentation rates. Land-use distribution within the watershed 

may also play a role in reservoir sedimentation. Conversely, 

Loch Raven Reservoir’s sedimentation rate (between those of 

Lake Linganore and Piney Run) may be a result of a larger and 

more developed watershed.

Summary

A bathymetric survey and sediment analysis was 

performed by the U.S. Geological Survey, in cooperation 

with the City of Frederick and Frederick County, Maryland in 

Lake Linganore, Frederick County, Maryland. The survey was 

conducted in order to calculate water volume and sediment 

accumulation in the lake to better understand sediment and 

phosphorus loadings and to better manage water resources. 

Bathymetric data points were collected to determine the 

elevation of the lake bottom. To determine the amount of 

sediment accumulated since the construction of the dam in 

1972, contour lines of the study area prior to dam construction 

were digitized and a surface was created using Geographic 

Information System software. Current water and sediment 

volumes were calculated using Triangulated Irregular Network 

models and by comparing the current lake bottom to the 

pre-inundation topography of the study area. The total water 

volume of the reservoir as calculated in 2009 was 1,860 acrefeet. Accumulated sediment volume in the reservoir since 

the dam was constructed in 1972 was 313 acre-feet. Due to 

sediment deposition in the lake, water volume has decreased 

approximately 16 percent. An analysis of the distribution of 

the sediment indicated that the largest volume of sediment was 

located in the most upstream third of Lake Linganore, whereas 

the third of the lake closest to the dam contained the largest 

amount of water. Lake Linganore was found to have one of 

the lowest sedimentation rates in comparison to three other 

Maryland Piedmont reservoirs, at 0.26 cubic yards per year 

per acre of drainage area. 

Figure 11. Generalized cross section of Lake Linganore from section 1, Lake Linganore, Maryland, 2009.
14 Water Volume and Sediment Accumulation in Lake Linganore, Frederick County, Maryland, 2009

Acknowledgments

The authors wish to thank Andrew LaMotte and Michael 

Wieczorek (USGS) for their GIS and cartography assistance. 

William Davies (USGS) also provided excellent support and 

guidance with electrical equipment and set-up. The authors 

also wish to thank Ray Baker, who was the boat operator during data collection.

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Prepared by USGS West Trenton Publishing Service Center.

Edited by Valerie M. Gaine.

Graphics and layout by Timothy W. Auer.

For additional information, contact:

Director, MD-DE-DC Water Science Center

U.S. Geological Survey

5522 Research Park Drive

Baltimore, MD 21228

or visit our Web site at:

http://md.water.usgs.gov
Sekellick, A.J. and Banks, W.S.L.— Water Volume and Sediment Accumulation in Lake Linganore, Frederick County, MD, 2009—Scientific Investigations Report 2010–5174

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