Prepared in cooperation with the Muskingum Watershed Conservancy District

An Analysis of Potential Water Availability from the 

Atwood, Leesville, and Tappan Lakes in the 

Muskingum River Watershed, Ohio

Scientific Investigations Report 2013–5112

U.S. Department of the Interior

U.S. Geological Survey
Cover image. Aerial view of Tappan Lake in the Muskingum River Watershed, Ohio. Rendering based on 

original photograph provided by the Muskingum Watershed Conservancy District (used with permission).
An Analysis of Potential Water Availability 

from the Atwood, Leesville, and Tappan Lakes 

in the Muskingum River Watershed, Ohio

By G.F. Koltun

Prepared in cooperation with the Muskingum Watershed Conservancy District

Scientific Investigations Report 2013–5112

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: 2013

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Suggested citation:

Koltun, G.F., 2013, An analysis of potential water availability from the Atwood, Leesville, and Tappan Lakes in the 

Muskingum River Watershed, Ohio: U.S. Geological Survey Scientific Investigations Report 2013–5112, 33 p.
iii

Contents

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

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

Descriptions of the Lakes....................................................................................................................3

Purpose and Scope ..............................................................................................................................3

Flow Data Used in the Analyses.........................................................................................................3

Methods of Analysis......................................................................................................................................4

Results and Discussion.................................................................................................................................6

Limitations.....................................................................................................................................................22

References Cited..........................................................................................................................................31

Glossary.........................................................................................................................................................31

Figures

1. Map showing locations of lakes and streamgages in the 

Muskingum River Watershed, Ohio...........................................................................................2

2. Flowchart outlining the logic by which withdrawal and flow-by amounts 

were determined...........................................................................................................................5

3. Graph showing surplus-water mass curves based on current target 

minimum outflows for the Atwood, Leesville, and Tappan Lakes in the 

Muskingum River Watershed, Ohio.........................................................................................30

Tables

1. U.S. Geological Survey streamgages and periods of gage record used 

in the water-availability analyses for the Muskingum River Watershed, Ohio ..................3

2. Statistics of calendar-year potential withdrawls for the Attwood, Leesville, 

and Tappan Lakes in the Muskingum River Watershed, Ohio...............................................7

3. Statistics of Atwood Lake, Ohio, total monthly potential withdrawals for 

indicated pumping rates and target minimum flow-by amounts ..........................................8

4. Statistics of Leesville Lake, Ohio, total monthly potential withdrawals for 

indicated pumping rates and target minimum flow-by amounts ........................................10

5. Statistics of Tappan Lake, Ohio, total monthly potential withdrawals for 

indicated pumping rates and target minimum flow-by amounts ........................................12

6. Analytical period statistics of observed daily mean outflows from the Atwood, 

Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio..........................14

7. Statistics of observed daily mean outflows by month for the Atwood, Leesville, 

and Tappan Lakes in the Muskingum River Watershed, Ohio............................................14

8. Statistics of daily mean flow-by amounts for indicated pumping rates and 

target minimum flow-by multiples for the Atwood, Leesville, and 

Tappan Lakes in the Muskingum River ...................................................................................15

9. Statistics of Atwood Lake, Ohio, daily mean flow-by amounts, by month, 

for indicated pumping rates and target minimum flow-by amounts ..................................16

10. Statistics of Leesville Lake, Ohio, daily mean flow-by amounts, by month, 

for indicated pumping rates and target minimum flow-by amounts ..................................18
iv

11. Statistics of Tappan Lake, Ohio, daily mean flow-by amounts, by month, 

for indicated pumping rates and target minimum flow-by amounts ..................................20

12. Daily mean flow-by statistics for the Atwood, Leesville, and Tappan Lakes, 

Muskingum River Watershed, Ohio, expressed as a percentage of observed 

outflow statistics.........................................................................................................................23

13. Monthly statistics of Atwood Lake, Ohio, daily mean flow-by amounts 

for indicated pumping rates and target minimum flow-by amounts, 

expressed as a percentage of corresponding statistic based on 

observed outflows ......................................................................................................................24

14. Monthly statistics of Leesville Lake, Ohio, daily mean flow-by amounts 

for indicated pumping rates and target minimum flow-by amounts, 

expressed as a percentage of corresponding statistic based on 

observed outflows ......................................................................................................................26

15. Monthly statistics of Tappan Lake, Ohio, daily mean flow-by amounts 

for indicated pumping rates and target minimum flow-by amounts, 

expressed as a percentage of corresponding statistic based on 

observed outflows ......................................................................................................................28

Appendix 1.

1-1. Table of cumulative surplus water at the Atwood, Leesville, and Tappan Lakes 

as a function of target minimum flow-by amount..................................................................33
v

Conversion Factors and Abbreviations

Multiply By To obtain

Length

foot (ft) 0.3048 meter (m)

Area

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Volume

million gallons (Mgal) 3,785.0 cubic meter (m3)

Flow rate

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

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

Abbreviations

MWCD Muskingum Watershed Conservancy District

SAS Statistical Analysis System

USACE U.S. Army Corps of Engineers

USGS U.S. Geological Survey 

An Analysis of Potential Water Availability from the 

Atwood, Leesville, and Tappan Lakes in the 

Muskingum River Watershed, Ohio

By G.F. Koltun 

Abstract 

This report presents the results of a study to assess 

potential water availability from the Atwood, Leesville, and 

Tappan Lakes, located within the Muskingum River Watershed, Ohio. The assessment was based on the criterion that 

water withdrawals should not appreciably affect maintenance 

of recreation-season pool levels in current use. To facilitate 

and simplify the assessment, it was assumed that historical 

lake operations were successful in maintaining seasonal pool 

levels, and that any discharges from lakes constituted either 

water that was discharged to prevent exceeding seasonal pool 

levels or discharges intended to meet minimum in-stream flow 

targets downstream from the lakes. It further was assumed 

that the volume of water discharged in excess of the minimum 

in-stream flow target is available for use without negatively 

impacting seasonal pool levels or downstream water uses and 

that all or part of it is subject to withdrawal.

Historical daily outflow data for the lakes were used 

to determine the quantity of water that potentially could be 

withdrawn and the resulting quantity of water that would 

flow downstream (referred to as “flow-by”) on a daily basis 

as a function of all combinations of three hypothetical target 

minimum flow-by amounts (1, 2, and 3 times current minimum in-stream flow targets) and three pumping capacities 

(1, 2, and 3 million gallons per day). Using both U.S. Geological Survey streamgage data and lake-outflow data provided 

by the U.S. Army Corps of Engineers resulted in analytical 

periods ranging from 51 calendar years for the Atwood Lake 

to 73 calendar years for the Leesville and Tappan Lakes.

The observed outflow time series and the computed 

time series of daily flow-by amounts and potential withdrawals were analyzed to compute and report order statistics 

(95th, 75th, 50th, 25th, 10th, and 5th percentiles) and means 

for the analytical period, in aggregate, and broken down by 

calendar month. In addition, surplus-water mass curve data 

were tabulated for each of the lakes.

Monthly order statistics of computed withdrawals 

indicated that, for the three pumping capacities considered, 

increasing the target minimum flow-by amount tended to 

reduce the amount of water that can be withdrawn. 

The reduction was greatest in the lower percentiles of withdrawal; however, increasing the flow-by amount had no impact 

on potential withdrawals during high flow. In addition, for a 

given target minimum flow-by amount, increasing the pumping 

rate increased the total amount of water that could be withdrawn; however, that increase was less than a direct multiple of 

the increase in pumping rate for most flow statistics. Potential 

monthly withdrawals were observed to be more variable and 

more limited in some calendar months than others.

Monthly order statistics and means of computed daily 

mean flow-by amounts indicated that flow-by amounts generally tended to be lowest during June–October and February. 

Increasing the target minimum flow-by amount for a given 

pumping rate resulted in some small increases in the magnitudes 

of the mean and 50th percentile and lower order statistics of 

computed mean flow-by, but had no effect on the magnitudes of 

the higher percentile statistics. Increasing the pumping rate for a 

given target minimum flow-by amount resulted in decreases in 

magnitudes of higher-percentile flow-by statistics by an amount 

equal to the flow equivalent of the increase in pumping rate; 

however, some lower percentile statistics remained unchanged.

Introduction

The Muskingum Watershed Conservancy District 

(MWCD)—a political subdivision of the State of Ohio—was 

created in 1933 under the Conservancy Act (Ohio Revised 

Code, Chapter 6101) (LAWriter Ohio Laws and Rules, 2000). 

In addition to flood reduction and protection, other approved 

purposes of the MWCD include conserving and developing 

water supplies for domestic, industrial, and public use; treating wastewater; and providing recreational opportunities. In 

support of the MWCD’s role in developing water supplies, a 

study was conducted by the U.S. Geological Survey (USGS), 

in cooperation with the MWCD, to assess potential water availability from the Atwood, Leesville, and Tappan Lakes, located 

within the Muskingum River Watershed, Ohio (fig. 1). These 

lakes, which have been operational since fall 1936, are operated 

by the U.S. Army Corps of Engineers (USACE) in partnership 

with the MWCD. 
2 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

!

!

03128500 !

03121500

03120500

Leesville Lake

Tappan Lake

Indian Fork

McGuire Creek

Little Stillwater Creek

OHIO

0 2.5 5

0 .5 52

MILES

KILOMETERS

Base from U.S. Geological Survey digital data

Universal Tranverse Mercator projection, Zone 17

North American Datum of 1983

! 03121500

Tappan Lake drainage

Leesville Lake drainage

Atwood Lake drainage

Muskingum River Watershed

Streams and lakes

Streamgages and number

EXPLANATION

CARROLL

HARRISON

TUSCARAWAS

81 ̊0' 81 ̊15'

40 ̊30'

40 ̊20'

Atwood Lake

Figure 1. Locations of lakes and streamgages in the Muskingum River Watershed, Ohio.
Introduction 3

The MWCD stipulated that the water-availability assessment be based on the criterion that water withdrawals should 

not appreciably affect maintenance of recreation-season pool 

levels in current use. To facilitate and simplify the water-availability analyses, it was assumed that historical lake operations 

were successful in maintaining seasonal pool levels, and that 

any discharges from the lakes constituted either water that 

was discharged to prevent exceeding seasonal pool levels or 

discharges intended to meet minimum in-stream flow targets 

downstream from the lakes. It is assumed that volumes of 

water discharged in excess of minimum in-stream flow targets 

(hereafter referred to as “surplus water”) are, by definition, 

available for use without negatively impacting seasonal pool 

levels or downstream water uses. The residual lake outflow 

(that is, the outflow minus withdrawals, if any) will be referred 

to as the “flow-by” because that water flows by (or through) 

the lake and is available for downstream uses.

Descriptions of the Lakes

The lakes addressed in this report include Atwood, 

Leesville, and Tappan. The dams that form these lakes were 

all completed in 1936. While the primary purpose of the lakes 

is flood control, they also were designed to provide storage 

for water conservation and recreation and to promote fish and 

wildlife enhancement. 

Atwood Lake, which has a drainage area of about 

70 square miles (mi2), is located in Tuscarawas and Carroll 

Counties, Ohio, on the Indian Fork of Conotton Creek (fig. 1). 

The Atwood Dam is a 65 feet (ft) high rolled-earth fill with 

impervious core (U.S. Army Corps of Engineers, 2013a). The 

outlet works consist of an approach channel, intake structure, tri-channeled conduit, stilling basin, and outlet channel 

(U.S. Army Corps of Engineers, 2005). 

Leesville Lake, which has a drainage area of about 

48.3 mi2, is located in southwest Carroll County, Ohio, on 

McGuire Creek (a tributary of Conotton Creek) (fig. 1). The 

Leesville Dam is a 74 ft high rolled-earth fill with impervious 

core (U.S. Army Corps of Engineers, 2013b). The outlet works 

consist of an approach channel, intake structure, horseshoeshaped tunnel, open-cut conduit section, stilling basin, and 

outlet channel (U.S. Army Corps of Engineers, 2005). 

Tappan Lake, which has a drainage area of about 

71.1 mi2, is located in northwest Harrison County, Ohio, on 

Little Stillwater Creek (fig. 1). The Tappan Dam is a 52 ft high 

rolled-earth fill with impervious core (U.S. Army Corps of 

Engineers, 2013c). The outlet works consist of an approach 

channel, intake structure, horseshoe-shaped tunnel, stilling 

basin, and outlet channel (U.S. Army Corps of Engineers, 2005). 

At each of the lakes previously discussed, normal flow 

(that is, when inflows to the lakes result in pool levels that 

are lower than emergency spillways present at each lake) is 

controlled by three 3.5 ft by 7 ft sluice gates. In addition, two 

ungated 1.5 ft diameter siphons are used at each lake to help 

maintain the minimum pool elevation. The USACE has set 

minimum in-stream flow targets, immediately downstream 

from the lakes, of 1.5 cubic feet per second (ft3/s) for Atwood 

and Leesville and 2.0 ft3/s for Tappan. It is worth noting that 

during very dry periods, it is possible to release less than the 

minimum in-stream flow target (if the lake level falls below 

the exposed circular intake to the siphons). Also, because 

of gate leakage, it is possible that flows as low as the minimum in-stream flow targets do not occur (Timothy Curran, 

U.S. Army Corps of Engineers, Huntington District, written 

commun., 2012). 

Purpose and Scope

The purpose of this report is to describe analytical methods and present results of a study to assess potential water 

availability from the Atwood, Leesville, and Tappan Lakes in 

the Muskingum River Watershed, Ohio. The analysis involved 

determining the amounts of water that potentially could be 

withdrawn and the resulting amounts of water that would flow 

downstream on a daily basis as a function of all combinations of three hypothetical target minimum flow-by amounts 

(1, 2, and 3 times current minimum in-stream flow targets) and 

three pumping capacities (1, 2, and 3 million gallons per day 

(Mgal/d)). The analysis was based on an examination of the 

best available historical daily outflow data for the lakes.

Flow Data Used in the Analyses

Lake-outflow data used for this report came from 

either daily mean streamflows published by the USGS for 

streamgages located short distances downstream from the outlet works of the lakes (table 1 and fig. 1) or from daily mean 

outflow data provided by the USACE. The streamflow data 

published by the USGS were determined based on relations 

developed between water-level data and physical measurements of streamflow. The USACE stated that they typically 

Table 1. U.S. Geological Survey streamgages and periods of gage record used in the water-availability analyses for the Muskingum 

River Watershed, Ohio.

Station number Station name Period of streamgage record used

03121500 Indian Fork below Atwood Dam near New Cumberland, Ohio 01/01/1961 – 09/30/1975

03120500 McGuire Creek near Leesville, Ohio 01/01/1939 – 09/30/1991

03128500 Little Stillwater Creek below Tappan Dam at Tappan, Ohio 01/01/1939 – 09/30/1991
4 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

used gate and siphon ratings to compute the outflows for the 

lakes and indicated that the accuracy of their reported flows 

may be poor during some low-flow periods (for example, 

due to unaccounted for gate leakages) (Timothy Curran, 

U.S. Army Corps of Engineers, Huntington District, written 

commun., June, 2012). 

Pearson’s correlation coefficient (r), which measures 

the strength of the linear relationship between two variables, 

was computed for each lake for the relation between sameday USGS-published streamflows and USACE-computed 

outflows. Pearson’s r can range from −1 to 1 where an r of ±1 

indicates a perfect linear relationship between variables and an 

r of 0 indicates no linear relationship between variables. When 

considering all concurrent flow data, the r values ranged from 

a low of 0.95 to a high of 0.96 for the three lake outflows. Correlation coefficients computed based on only those paired flow 

values where the USACE outflow was reported to be less than 

or equal to 10 ft3/s, were considerably smaller (r ranging from 

0.19 to 0.60), indicating poorer correlation than for the full 

data set. For all three lakes, the largest differences between 

the USGS-published streamflows and the USACE-computed 

outflows for flows less than or equal to 10 ft3/s predominately 

were associated with times when the USGS-published streamflows were larger than the USACE-computed outflows. 

Because of the stated uncertainty surrounding the lowflow data supplied by the USACE, the USGS streamgage data 

were used whenever available; USACE data were used at 

other times. The resulting daily-mean-outflow time series will 

henceforth be referred to as the “observed” outflows.

The three USGS streamgages whose data were used in 

this report, along with the periods of record used, are shown in 

table 1. The USACE provided lake-outflow data for the period 

01/01/1962 to12/31/2011 for the Atwood, Leesville, and Tappan Lakes. Using both streamgage and outflow data provided 

by the USACE resulted in analytical periods ranging from 

51 calendar years (1961–2011) for Atwood Lake to 73 calendar years (1939–2011) for the Leesville and Tappan Lakes.

Methods of Analysis

To assess potential future water availability, observed outflow data from the Atwood, Leesville, and Tappan Lakes were 

used to determine the amounts of water that potentially could 

be withdrawn and the resulting residual amounts of water that 

would flow downstream (referred to as “flow-by”) on a daily 

basis as a function of all combinations of three hypothetical 

target minimum flow-by amounts and three pumping capacities. It is worth noting that the “target minimum flow-by 

amounts” represent targets (not regulatory mandates) for 

minimum daily mean flows immediately downstream from the 

lakes; however, there may be times when those targets cannot 

be met. The occasional inability to fulfill those targets in this 

analysis occurs because the flow-by comes from observed 

lake outflows, which at times was already less than the target. 

This might occur, for example, during extended dry periods 

when lake outflows are completely controlled by the siphons. 

Irrespective of the actual outflows from the lakes, in no case 

does the analytical method used for this report yield flow-by 

amounts less than the observed lake outflows. 

The target minimum flow-by amounts used in this 

analysis were 1, 2, and 3 times the current minimum instream flow targets for the lakes (1.5 ft3

/s for the Atwood and 

Leesville Lakes and 2.0 ft3/s for Tappan Lake) as specified 

by the USACE. The pumping rates used in this analysis were 

1, 2, and 3 Mgal/d. Pumping rates and multipliers for target 

minimum flow-by amounts used in this analysis were specified 

by the MWCD.

As illustrated in figure 2, for each day in the lake outflow 

time series, the outflow amount was compared to the target 

minimum flow-by amount. If the outflow amount did not 

exceed the target minimum flow-by amount, then there was no 

surplus water available for withdrawal and the total outflow 

was designated as flow-by. If instead the outflow amount 

exceeded the target minimum flow-by amount, then the 

amount of outflow in excess of that target minimum flow-by 

amount was said to be surplus water.

The amount of surplus water was compared to the 

amount of water that could be pumped (withdrawn) in 1 day 

at the specified pumping rate. If the amount of surplus water 

exceeds that which could be pumped, then the withdrawal 

was set equal to the product of time and the pumping rate. For 

example, if the pumping rate was 1 Mgal/d, then the amount 

of water that could be pumped over a 24 hour period equals 

1 million gallons (Mgal). If instead the amount of surplus 

water did not exceed that which could be pumped in 1 day, 

then the withdrawal was set equal to the amount of surplus 

water (the assumption being that the pump would be operated 

only for the portion of the day required to pump the surplus 

amount). The resulting flow-by amount (that is the water that 

flows downstream) is equal to the outflow minus withdrawals (if any). This approach ensures that the resulting flow-by 

amount equals or exceeds the target minimum flow-by amount 

whenever the outflow exceeds the target minimum flow by. 

The observed outflow time series and the time series of 

daily flow-by amounts and potential withdrawals (computed 

as previously described) were analyzed to compute order 

statistics and means. The order statistics computed include the 

95th, 75th, 50th, 25th, 10th, and 5th percentiles. In general, 

the Pth percentile refers to the value in the series that is greater 

than or equal to P percent of values in the series. Conversely, 

the Pth percentile value is less than or equal to 100-P percent 

of the values in the series. For example, the 5th percentile 

value is greater than or equal to 5 percent of the values in the 

series and less than or equal to 95 percent (100-5 percent) of 

the values.

Order statistics and means were computed for daily mean 

observed outflows and computed flow-by amounts, as well as 

for monthly and annual total withdrawals. The ultimate objective of computing order statistics is to provide information 

on the frequency with which outflows, flow-by amounts, and 
Methods of Analysis 5

Outflow 

greater than 

minimum flow-by 

target?

Outflow from lake

Surplus water

= outflow-minimum flow-by target

Surplus water

= 0

Surplus 

water greater than

pumping rater?

Withdrawal

= pumping rate x time

Withdrawal

= surplus water

Withdrawal

= 0

Flow-by

Flow-by = outflow

= outflow – withdrawal

No

No

Yes

Yes

Figure 2. Flowchart outlining the logic by which withdrawal and flow-by amounts were determined.

withdrawals with various magnitudes were exceeded (or not 

exceeded). Order statistics were computed with the Statistical 

Analysis System (SAS) (SAS Institute, Inc., 2011) using the 

SAS type 5 estimator (which calculates percentiles based on 

the empirical distribution function with averaging when the 

percentile boundary lies between two observations). For some 

tables presented in this report, statistics are reported for the 

aggregate analytical period; for other tables, order statistics 

were computed based on data further subdivided by calendar 

month. The aggregate analytical-period order statistics provide 

information on exceedance/nonexceedance without consideration for seasonality, whereas the monthly order statistics 

provide more information about seasonal variation in the flows 

and potential withdrawals.

Cumulative surplus-water volumes were tabulated as a 

function of time for the Atwood, Leesville, and Tappan Lakes 

based on target minimum outflows equal to 1, 2, and 3 times 

current target minimum outflows. When cumulative volumes 

are plotted as a function of time, they are called mass curves. 

Both tabular and graphical versions of surplus-water mass 

curves can be used to assess hypothetical water-demand rates 

to determine whether the demand could have been met at all 

times or, if not, to determine the maximum amount and duration of demand excess.
6 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

Results and Discussion

Order statistics and means of calendar-year and monthly 

total withdrawals are shown in tables 2–5 for the various 

combinations of pumping rates and target minimum flow-by 

amounts. The data presented in table 2 show some general 

trends in withdrawal statistics for the Atwood, Leesville, and 

Tappan Lakes. Specifically, for any of the given pumping 

rates, increasing the target minimum flow-by amount tends to 

reduce the amount of water that can be withdrawn. The reduction is greatest in the lower percentiles of withdrawal because 

increasing the flow-by amount has a large impact on water 

available for withdrawal during low-flow periods; however, 

increasing the flow-by amount has no impact on potential 

withdrawals during high-flow periods because the amount of 

surplus water (from which withdrawals are made) already far 

exceeds pumping rates. 

For a given target minimum flow-by amount, increasing the pumping rate typically increases the total amount of 

water that can be withdrawn; however, that increase is less 

than a direct multiple of the increase in pumping rate for most 

statistics. This is because sufficient surplus water is available 

on some days to meet the demand associated with smaller 

pumping rates, but it may not be sufficient to meet the demand 

associated with larger pumping rates. When the amount of 

surplus water is not sufficient to meet the full demand associated with an increased pumping rate, the amount of additional 

withdrawal (beyond that which is associated with the lower 

pumping rate) will range from zero to some fraction of the 

difference in pump capacities.

Withdrawal data shown in tables 3–5 illustrate that potential monthly withdrawals are more variable and more limited 

in some calendar months than others. For example, withdrawal 

results for Atwood Lake (table 3) indicate that, irrespective 

of which target minimum flow-by amount is used, 1 Mgal of 

water could have been withdrawn daily at a pumping rate of 

1 Mgal/d on at least 90 percent of the April months; however, 

that same amount of withdrawal was possible on a smaller percentage of the September months. For example, with a pumping rate of 1 Mgal/d and a target minimum flow-by amount 

of 4.5 ft3/s, a daily withdrawal of 1 Mgal was not possible for 

Atwood Lake on at least 25 percent of September months. At 

that same pumping rate and target minimum flow-by amount, 

no water could be withdrawn from Atwood Lake on at least 

5 percent of the September months.

Aggregate analytical-period order statistics and monthly 

order statistics of observed daily mean outflows are reported 

in tables 6 and 7, respectively. Data from these tables provide 

a base against which to compare flow-by statistics from the 

analyses employing the various combinations of pumping and 

target minimum flow-by amounts. An examination of the data 

presented in table 7 indicates that the daily mean observed 

outflows for the Atwood, Leesville, and Tappan Lakes tend to 

be lowest during June–October, although February also stands 

out as having relatively low mean outflows. The relatively low 

mean outflows for February likely reflect the fact that February typically is one of the driest months in Ohio (Ohio Department of Natural Resources, 2011).

Aggregate analytical-period order statistics and means of 

computed daily mean flow-by amounts are shown in table 8 

for the Atwood, Leesville, and Tappan Lakes for the various 

combinations of pumping rates and target minimum flow-by 

amounts. The data show that increases in the target minimum 

flow-by amounts for a given pumping rate resulted in some 

small increases in the magnitudes of the means and 25th 

percentile and smaller order statistics, but had no effect on the 

magnitudes of the higher percentile statistics. Also, increases 

in the pumping rate for a given target minimum flow-by 

amount resulted in decreases in magnitudes of higher-percentile flow statistics by an amount equal to the flow equivalent of 

the increase in pumping rate; however, some lower-percentile 

flow statistics remained unchanged because they represent 

days during which there was no surplus water (and so withdrawals could not be increased on those days in spite of 

increases in pumping rate).

Monthly order statistics and means of computed daily 

mean flow-by amounts are shown in tables 9–11 for the 

Atwood, Leesville, and Tappan Lakes, respectively, for the 

various combinations of pumping rates and target minimum 

flow-by amounts. Similar to the observed outflows, computed 

mean flow-by amounts generally tended to be lowest during June–October and mean flow-by amounts for February 

also tended to be relatively low. The data in tables 9–11 show 

that increases in the target minimum flow-by amounts for a 

given pumping rate resulted in some small increases in the 

magnitudes of the mean and 50th percentile and lower order 

statistics, but had no effect on the magnitudes of the higher 

percentile statistics. As was observed with the aggregate analytical-period order statistics, increases in the pumping rate for 

a given target minimum flow-by amount resulted in decreases 

in magnitudes of higher-percentile flow statistics by an amount 

equal to the flow equivalent of the increase in pumping rate; 

however, some lower percentile statistics remained unchanged.
Results and Discussion 7

Table 2. Statistics of calendar-year potential withdrawls for the Attwood, Leesville, and Tappan Lakes in the Muskingum River 

Watershed, Ohio.

[Mgal/d, million gallons per day; minimum in-stream flow targets equal 1.5 cubic feet per second (ft3/s) for Atwood and Leesville Lakes and 2.0 ft3/s for Tappan Lake] 

Statistic

Calendar-year potential withdrawals, in millions of gallons, for indicated lakes, pumping rates, 

and minimum in-stream flow-target multiples

Pumping rate, in Mgal/d

1 2 3

Minimum in-stream flow-target multiple

1 2 3 1 2 3 1 2 3

Atwood Lake

95th percentile 365 365 365 730 730 730 1095 1095 1095

75th percentile 365 364 364 729 728 724 1092 1089 1085

mean 351 338 332 689 670 658 1020 995 978

50th percentile 361 358 355 719 714 708 1075 1063 1059

25th percentile 341 319 305 652 627 609 961 916 910

10th percentile 313 266 244 603 510 473 850 739 692

5th percentile 303 245 230 544 469 454 783 693 667

Leesville Lake

95th percentile 365 362 354 726 716 705 1080 1066 1044

75th percentile 354 335 321 685 651 633 999 957 925

mean 321 293 276 613 568 535 887 827 782

50th percentile 331 301 276 632 577 522 905 828 762

25th percentile 293 256 241 548 498 461 793 723 666

10th percentile 276 227 204 505 421 390 708 616 569

5th percentile 240 209 186 448 394 365 646 573 534

Tappan Lake

95th percentile 364 364 361 728 723 717 1088 1082 1075

75th percentile 349 331 320 677 654 625 1005 966 912

mean 316 292 277 612 572 546 895 843 805

50th percentile 331 296 287 636 588 558 914 877 822

25th percentile 292 254 234 549 491 463 814 709 685

10th percentile 254 230 201 482 438 396 702 625 586

5th percentile 244 203 179 452 388 351 650 558 513
8 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

Table 3. Statistics of Atwood Lake, Ohio, total monthly potential withdrawals for indicated pumping rates and target minimum flow-by 

amounts.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Total monthly potential withdrawals, in millions of gallons, for indicated months and pump rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 1 Mgal/d

1.5

95th percentile 31.0 29.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

75th percentile 31.0 28.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

mean 30.6 25.8 30.2 29.7 31.0 29.8 29.8 29.2 27.3 28.8 28.5 30.2

50th percentile 31.0 28.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

25th percentile 31.0 26.6 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

10th percentile 29.5 15.3 27.9 30.0 31.0 30.0 26.3 24.5 16.0 22.5 24.7 29.0

5th percentile 28.0 13.8 25.6 30.0 31.0 29.0 22.6 17.5 13.3 13.0 19.0 27.0

3.0

95th percentile 31.0 29.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

75th percentile 31.0 28.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

mean 30.3 24.4 28.9 29.4 30.9 29.7 29.0 27.1 25.0 27.3 27.5 29.6

50th percentile 31.0 28.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

25th percentile 30.5 24.0 28.0 30.0 31.0 30.0 31.0 29.5 27.9 31.0 30.0 31.0

10th percentile 28.3 10.4 23.5 30.0 31.0 29.7 18.5 11.3 1.6 13.9 18.0 27.4

5th percentile 27.0 1.0 16.0 28.7 31.0 29.0 16.0 5.7 0.0 3.6 14.9 22.3

4.5

95th percentile 31.0 29.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

75th percentile 31.0 28.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

mean 30.1 24.3 28.6 29.3 30.9 29.6 28.6 26.7 24.7 26.9 27.4 29.5

50th percentile 31.0 28.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

25th percentile 30.1 24.0 28.0 30.0 31.0 30.0 31.0 28.9 26.3 30.9 29.8 31.0

10th percentile 28.2 10.2 22.4 30.0 31.0 29.5 16.1 8.8 1.0 10.5 17.0 26.3

5th percentile 27.0 1.0 15.4 28.1 30.6 28.3 14.9 5.4 0.0 1.3 12.4 20.2

Pumping rate = 2 Mgal/d

1.5

95th percentile 62.0 58.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

75th percentile 62.0 56.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

mean 60.9 50.2 59.0 59.1 61.9 59.5 58.7 56.3 52.2 56.1 56.0 59.7

50th percentile 62.0 56.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

25th percentile 61.4 50.1 57.0 60.0 62.0 60.0 62.0 60.4 57.7 62.0 60.0 62.0

10th percentile 57.0 23.6 50.5 60.0 62.0 59.7 43.8 35.5 21.3 33.7 42.3 55.5

5th percentile 54.0 15.1 42.7 58.6 61.9 58.0 40.9 22.8 13.3 18.3 38.0 50.7

3.0

95th percentile 62.0 58.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

75th percentile 62.0 56.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

mean 60.2 48.6 57.1 58.6 61.8 59.1 56.8 52.9 49.2 53.7 54.7 58.9

50th percentile 62.0 56.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

25th percentile 60.3 47.3 56.0 60.0 62.0 60.0 61.9 56.5 51.9 59.9 58.5 62.0

10th percentile 56.2 20.0 45.0 60.0 62.0 59.0 30.9 15.3 2.1 21.5 34.0 52.6

5th percentile 54.0 2.0 27.3 55.7 59.8 55.5 26.3 10.2 0.0 3.6 24.3 41.7
Results and Discussion 9

Table 3. Statistics of Atwood Lake, Ohio, total monthly potential withdrawals for indicated pumping rates and target minimum flow-by 

amounts.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Total monthly potential withdrawals, in millions of gallons, for indicated months and pump rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 2 Mgal/d—Continued

4.5

95th percentile 62.0 58.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

75th percentile 62.0 56.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

mean 60.0 48.4 56.8 58.6 61.7 59.0 56.0 52.0 48.7 53.2 54.4 58.8

50th percentile 62.0 56.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

25th percentile 60.0 47.0 56.0 60.0 62.0 60.0 61.4 54.5 51.3 58.9 57.6 62.0

10th percentile 55.9 19.5 43.9 60.0 62.0 58.8 29.1 12.7 1.5 19.7 34.0 51.3

5th percentile 54.0 1.8 25.8 54.3 58.3 53.7 21.2 5.8 0.0 1.3 23.6 39.2

Pumping rate = 3 Mgal/d

1.5

95th percentile 93.0 87.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

75th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

mean 90.8 74.4 87.3 88.3 92.7 88.9 86.5 82.0 76.4 82.5 83.1 89.1

50th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

25th percentile 91.3 72.6 84.9 90.0 93.0 90.0 92.9 87.3 81.0 90.8 88.4 93.0

10th percentile 85.0 32.1 72.1 90.0 93.0 88.5 54.1 38.7 21.3 43.1 56.2 81.5

5th percentile 81.0 15.1 54.9 85.6 90.7 85.4 49.4 22.8 13.3 23.9 47.5 70.1

3.0

95th percentile 93.0 87.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

75th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

mean 89.8 72.4 85.3 87.8 92.5 88.2 83.2 77.2 72.6 79.9 81.6 88.2

50th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 92.5 90.0 93.0 90.0 93.0

25th percentile 90.0 69.0 84.0 90.0 93.0 90.0 90.2 81.0 76.9 84.6 85.5 93.0

10th percentile 83.2 29.0 66.5 90.0 93.0 86.6 41.8 16.9 2.6 30.9 51.0 77.6

5th percentile 81.0 2.1 38.9 78.7 87.0 76.6 30.5 10.5 0.0 3.6 34.5 60.7

4.5

95th percentile 93.0 87.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

75th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

mean 89.4 72.2 85.0 87.6 92.4 87.9 82.0 75.7 71.8 79.2 81.4 88.1

50th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 91.6 90.0 93.0 90.0 93.0

25th percentile 89.4 64.5 84.0 90.0 93.0 90.0 87.7 78.0 76.2 84.0 84.6 93.0

10th percentile 82.3 28.5 65.4 90.0 93.0 85.6 39.2 13.8 2.0 27.2 51.0 76.3

5th percentile 80.8 1.8 37.1 77.4 87.0 72.7 24.6 5.8 0.0 1.3 33.6 58.2
10 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

Table 4. Statistics of Leesville Lake, Ohio, total monthly potential withdrawals for indicated pumping rates and target minimum 

flow-by amounts.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Total monthly potential withdrawals, in millions of gallons, for indicated months and pump rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 1 Mgal/d

1.5

95th percentile 31.0 29.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

75th percentile 31.0 28.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

mean 30.0 22.3 26.7 28.7 29.9 29.0 28.2 24.9 21.5 24.1 26.2 28.8

50th percentile 31.0 26.6 30.6 30.0 31.0 30.0 31.0 30.3 27.8 30.9 30.0 31.0

25th percentile 30.6 17.2 25.0 30.0 31.0 30.0 30.1 22.1 13.0 17.9 26.7 29.9

10th percentile 26.9 10.0 15.7 27.7 31.0 28.4 22.5 7.6 3.4 4.0 15.0 23.9

5th percentile 25.0 6.4 12.3 18.2 20.0 23.5 11.0 5.0 2.5 0.7 6.2 21.1

3.0

95th percentile 31.0 29.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

75th percentile 31.0 28.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

mean 28.5 18.9 24.5 28.3 29.8 28.0 25.3 20.5 16.9 20.3 24.7 27.1

50th percentile 31.0 23.9 30.0 30.0 31.0 30.0 31.0 24.2 20.1 29.0 30.0 30.3

25th percentile 27.0 10.0 20.0 30.0 31.0 29.8 21.6 12.7 1.9 6.0 20.5 27.4

10th percentile 23.4 1.0 11.0 25.0 30.4 24.3 10.8 0.0 0.0 0.0 7.1 15.4

5th percentile 18.7 0.0 1.0 15.0 19.3 13.5 0.1 0.0 0.0 0.0 0.8 7.0

4.5

95th percentile 31.0 29.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

75th percentile 31.0 28.0 31.0 30.0 31.0 30.0 31.0 31.0 29.6 31.0 30.0 31.0

mean 28.0 18.7 24.3 28.2 29.7 27.7 24.6 19.4 15.9 19.4 24.5 26.5

50th percentile 31.0 23.3 30.0 30.0 31.0 30.0 30.9 21.1 18.0 26.8 30.0 30.0

25th percentile 26.6 9.7 20.0 30.0 31.0 29.3 20.7 10.7 0.3 4.4 20.1 25.2

10th percentile 20.9 1.0 11.0 24.5 29.2 23.0 7.5 0.0 0.0 0.0 6.0 15.0

5th percentile 17.0 0.0 1.0 15.0 19.0 12.7 0.0 0.0 0.0 0.0 0.0 7.0

Pumping rate = 2 Mgal/d

1.5

95th percentile 62.0 58.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

75th percentile 62.0 56.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

mean 58.5 41.2 51.2 57.0 59.7 57.0 53.4 45.3 38.4 44.4 50.9 55.9

50th percentile 62.0 50.6 60.4 60.0 62.0 60.0 62.0 54.6 47.5 59.4 60.0 61.3

25th percentile 56.4 24.2 44.9 60.0 62.0 59.8 51.2 34.3 17.5 24.2 46.2 57.6

10th percentile 51.3 16.0 25.3 52.7 61.4 52.0 33.4 7.6 3.4 4.0 24.3 40.4

5th percentile 46.5 7.2 15.7 33.2 39.2 38.8 11.5 5.1 2.5 0.7 7.6 25.7

3.0

95th percentile 62.0 58.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

75th percentile 62.0 56.0 62.0 60.0 62.0 60.0 62.0 61.2 57.7 62.0 60.0 62.0

mean 55.6 37.0 48.5 56.4 59.4 55.0 48.3 37.6 30.9 37.8 48.8 52.6

50th percentile 61.0 46.7 58.5 60.0 62.0 60.0 60.6 39.8 33.8 52.1 60.0 59.4

25th percentile 52.2 19.0 40.0 60.0 62.0 58.0 40.6 20.2 1.9 8.4 40.5 49.6

10th percentile 41.5 2.0 22.0 48.6 57.3 42.8 15.3 0.0 0.0 0.0 12.0 28.3

5th percentile 29.7 0.0 2.0 28.5 38.3 22.9 0.1 0.0 0.0 0.0 0.8 14.0
Results and Discussion 11

Table 4. Statistics of Leesville Lake, Ohio, total monthly potential withdrawals for indicated pumping rates and target minimum 

flow-by amounts.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Total monthly potential withdrawals, in millions of gallons, for indicated months and pump rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 2 Mgal/d—Continued

4.5

95th percentile 62.0 57.9 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

75th percentile 62.0 56.0 62.0 60.0 62.0 60.0 62.0 59.8 56.4 62.0 60.0 62.0

mean 54.8 36.4 48.0 56.3 59.2 54.3 46.8 35.6 29.2 36.1 48.3 51.7

50th percentile 60.6 42.8 58.0 60.0 62.0 60.0 59.4 36.5 27.9 49.6 59.6 58.7

25th percentile 50.0 18.7 39.7 60.0 62.0 57.7 37.2 16.8 0.3 4.4 40.1 47.3

10th percentile 40.9 2.0 22.0 47.5 55.7 37.8 10.3 0.0 0.0 0.0 12.0 27.0

5th percentile 23.5 0.0 1.9 28.2 37.8 19.4 0.0 0.0 0.0 0.0 0.0 10.1

Pumping rate = 3 Mgal/d

1.5

95th percentile 93.0 87.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

75th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 92.0 87.6 93.0 90.0 93.0

mean 85.6 59.2 75.1 85.1 89.3 83.9 76.3 62.3 52.3 61.8 75.0 81.4

50th percentile 91.9 74.1 89.0 90.0 93.0 90.0 91.5 68.3 59.2 80.8 90.0 90.1

25th percentile 81.2 29.0 64.8 90.0 93.0 87.7 64.7 39.6 17.5 29.4 64.9 79.4

10th percentile 69.3 16.2 36.3 76.3 88.1 71.8 37.4 7.6 3.4 5.0 30.5 53.7

5th percentile 59.5 7.2 15.7 46.4 58.2 43.4 11.5 5.1 2.5 0.7 7.6 28.7

3.0

95th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

75th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 86.2 81.6 91.5 90.0 93.0

mean 81.8 54.2 71.6 84.3 88.8 80.8 69.0 52.1 42.8 52.8 71.9 77.2

50th percentile 89.3 63.9 87.0 90.0 93.0 90.0 85.4 51.4 40.7 70.1 88.4 88.4

25th percentile 74.6 28.0 58.0 90.0 93.0 85.4 53.7 23.3 1.9 8.4 60.3 70.1

10th percentile 60.3 3.0 33.0 70.6 83.3 52.6 15.3 0.0 0.0 0.0 18.0 39.3

5th percentile 39.7 0.0 2.2 42.5 56.4 24.9 0.1 0.0 0.0 0.0 0.8 16.2

4.5

95th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

75th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 83.9 78.1 88.9 90.0 93.0

mean 80.8 53.4 71.0 84.1 88.6 79.6 66.8 49.4 40.5 50.3 71.0 76.0

50th percentile 88.7 62.2 86.3 90.0 93.0 89.9 83.0 48.0 34.1 60.2 87.3 87.7

25th percentile 73.6 27.7 51.5 90.0 93.0 83.9 48.7 16.8 0.3 4.4 57.9 68.3

10th percentile 57.5 3.0 33.0 70.0 81.7 45.6 11.0 0.0 0.0 0.0 18.0 32.6

5th percentile 33.5 0.0 1.9 42.2 55.8 20.2 0.0 0.0 0.0 0.0 0.0 10.1
12 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

Table 5. Statistics of Tappan Lake, Ohio, total monthly potential withdrawals for indicated pumping rates and target minimum flow-by 

amounts.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Total monthly potential withdrawals, in millions of gallons, for indicated months and pump rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 1 Mgal/d

2.0

95th percentile 31.0 29.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

75th percentile 31.0 28.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

mean 29.0 21.9 25.5 27.4 29.6 28.6 28.1 24.2 21.6 24.4 27.1 28.7

50th percentile 31.0 27.0 30.5 30.0 31.0 30.0 31.0 31.0 28.7 31.0 30.0 31.0

25th percentile 29.0 15.6 22.7 29.0 31.0 30.0 29.2 18.5 13.3 21.2 27.2 30.1

10th percentile 26.0 8.0 11.6 23.0 31.0 24.0 20.5 9.1 1.8 4.6 18.6 23.2

5th percentile 20.1 4.4 8.0 7.8 17.6 19.7 13.7 4.0 0.0 1.7 15.2 17.1

4.0

95th percentile 31.0 29.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

75th percentile 31.0 28.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

mean 27.6 20.1 23.5 26.6 29.3 27.9 25.8 20.5 16.9 21.6 25.3 26.7

50th percentile 31.0 26.9 29.9 30.0 31.0 30.0 31.0 26.6 19.7 29.4 30.0 31.0

25th percentile 27.0 13.0 15.3 27.3 31.0 30.0 23.9 9.6 3.0 14.2 22.0 25.0

10th percentile 19.0 2.0 7.3 20.1 31.0 24.0 14.3 0.0 0.0 0.0 16.0 17.0

5th percentile 15.1 0.4 1.6 5.1 13.3 15.1 0.0 0.0 0.0 0.0 4.0 2.0

6.0

95th percentile 31.0 29.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

75th percentile 31.0 28.0 31.0 30.0 31.0 30.0 31.0 31.0 30.0 31.0 30.0 31.0

mean 26.8 19.4 23.0 26.3 29.1 27.1 24.0 17.8 14.4 19.1 24.1 25.9

50th percentile 31.0 25.0 28.0 30.0 31.0 30.0 30.6 21.1 10.8 24.0 30.0 31.0

25th percentile 25.8 11.0 15.0 25.8 31.0 28.6 19.4 2.5 0.0 6.5 20.0 23.0

10th percentile 17.0 1.0 5.7 18.1 30.7 17.1 11.0 0.0 0.0 0.0 13.2 15.0

5th percentile 5.4 0.0 0.1 4.0 9.6 10.7 0.0 0.0 0.0 0.0 0.0 2.0

Pumping rate = 2 Mgal/d

2.0

95th percentile 62.0 58.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

75th percentile 62.0 56.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

mean 56.9 42.1 49.2 54.2 59.0 56.6 54.4 45.4 39.3 46.5 52.7 55.8

50th percentile 62.0 54.0 60.0 60.0 62.0 60.0 62.0 57.6 50.5 61.2 60.0 62.0

25th percentile 56.3 28.3 37.5 56.6 62.0 60.0 52.1 31.8 17.3 39.2 50.0 55.2

10th percentile 45.6 13.3 18.7 44.4 62.0 48.0 36.0 11.3 1.8 4.6 33.6 39.1

5th percentile 40.1 5.4 11.1 13.2 31.4 33.2 19.5 5.0 0.0 1.7 20.5 24.2

4.0

95th percentile 62.0 58.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

75th percentile 62.0 56.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

mean 54.6 39.5 46.6 53.0 58.4 55.2 50.3 38.8 31.7 41.2 49.7 52.8

50th percentile 62.0 52.9 57.9 60.0 62.0 60.0 61.9 50.0 29.0 50.1 60.0 62.0

25th percentile 52.6 25.3 30.3 53.6 62.0 59.2 44.1 15.4 3.2 15.9 42.0 46.0

10th percentile 38.0 4.0 14.0 39.7 62.0 43.2 25.7 0.0 0.0 0.0 32.0 31.9

5th percentile 25.1 0.4 1.9 9.4 23.8 29.6 0.0 0.0 0.0 0.0 5.4 4.0
Results and Discussion 13

Table 5. Statistics of Tappan Lake, Ohio, total monthly potential withdrawals for indicated pumping rates and target minimum flow-by 

amounts.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Total monthly potential withdrawals, in millions of gallons, for indicated months and pump rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 2 Mgal/d—Continued

6.0

95th percentile 62.0 58.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

75th percentile 62.0 56.0 62.0 60.0 62.0 60.0 62.0 62.0 60.0 62.0 60.0 62.0

mean 53.0 38.6 45.7 52.3 58.1 53.8 46.8 34.0 27.7 36.7 47.8 51.1

50th percentile 62.0 49.1 56.0 60.0 62.0 60.0 59.1 36.0 18.1 44.8 60.0 62.0

25th percentile 46.8 22.0 30.0 50.6 62.0 53.9 34.9 4.0 0.0 11.7 40.0 44.0

10th percentile 34.0 2.0 10.4 34.5 60.3 33.4 12.3 0.0 0.0 0.0 23.2 28.7

5th percentile 8.0 0.0 0.1 8.0 18.6 18.7 0.0 0.0 0.0 0.0 0.0 3.2

Pumping rate = 3 Mgal/d

2.0

95th percentile 93.0 87.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

75th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

mean 84.1 61.7 72.4 80.6 88.1 84.0 79.3 64.3 54.6 66.8 77.3 82.0

50th percentile 93.0 81.0 88.5 90.0 93.0 90.0 93.0 81.5 64.6 86.0 90.0 93.0

25th percentile 81.5 39.6 47.8 83.6 93.0 89.7 75.5 36.1 20.3 48.5 71.6 78.2

10th percentile 64.0 16.0 25.7 64.3 93.0 72.0 49.8 11.3 1.8 4.6 49.6 54.1

5th percentile 57.0 6.4 11.8 17.8 42.9 48.0 19.5 5.0 0.0 1.7 22.4 36.0

4.0

95th percentile 93.0 87.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

75th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

mean 80.9 58.8 69.4 79.1 87.4 82.0 73.4 55.5 45.4 59.2 73.5 78.2

50th percentile 93.0 76.9 84.9 90.0 93.0 90.0 90.8 64.9 37.0 73.0 90.0 93.0

25th percentile 77.1 35.3 45.3 79.6 93.0 85.5 61.7 18.1 3.2 21.3 60.7 68.8

10th percentile 54.3 6.0 21.0 57.1 91.9 59.5 34.8 0.0 0.0 0.0 48.0 46.9

5th percentile 27.2 0.4 1.9 13.4 32.8 43.6 0.0 0.0 0.0 0.0 5.5 5.5

6.0

95th percentile 93.0 87.0 93.0 90.0 93.0 90.0 93.0 93.0 90.0 93.0 90.0 93.0

75th percentile 93.0 84.0 93.0 90.0 93.0 90.0 93.0 92.1 88.5 90.7 90.0 93.0

mean 78.9 57.6 68.1 78.2 87.0 79.5 67.9 48.7 39.9 52.6 70.9 75.7

50th percentile 91.8 72.6 84.0 90.0 93.0 90.0 85.7 48.0 24.1 58.6 87.5 93.0

25th percentile 69.0 33.0 45.0 75.6 93.0 78.4 45.9 6.0 0.0 16.7 59.0 62.5

10th percentile 50.6 3.0 15.4 50.5 86.1 46.8 12.3 0.0 0.0 0.0 33.2 39.2

5th percentile 12.0 0.0 0.1 12.0 26.6 26.7 0.0 0.0 0.0 0.0 0.0 4.2
14 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

Table 6. Analytical period statistics of observed daily mean outflows from the 

Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio.

Statistic

Observed daily mean outflow amounts for indicated lakes

(in cubic feet per second)

Atwood Lake Leesville Lake Tappan )Lake

95th percentile 320.0 218.7 363.0

75th percentile 105.3 88.0 105.5

mean 85.4 58.8 80.8

50th percentile 52.9 24.4 25.6

25th percentile 13.0 5.5 7.5

10th percentile 6.2 2.0 2.2

5th percentile 2.6 1.6 1.7

Minimum in-stream 

flow target

1.5 1.5 2.0

Table 7. Statistics of observed daily mean outflows by month for the Atwood, Leesville, and Tappan Lakes in the Muskingum River 

Watershed, Ohio.

Statistic

Observed daily mean reservoir outflows, in cubic feet per second, for indicated month and lake

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Atwood Lake

95th percentile 320.0 364.5 413.0 400.0 343.0 291.0 146.4 119.6 131.0 155.0 268.1 392.0

75th percentile 110.5 73.1 143.0 180.5 122.8 88.6 73.0 55.7 50.1 63.0 161.0 183.6

mean 84.1 74.2 108.5 145.9 110.0 83.8 54.2 41.5 43.4 47.4 110.6 122.2

50th percentile 32.0 16.0 76.0 99.9 76.0 62.0 44.9 21.2 17.7 25.0 98.0 67.7

25th percentile 18.0 10.7 11.2 72.1 55.7 28.0 11.0 7.8 8.2 11.2 42.0 22.0

10th percentile 10.6 2.2 10.0 35.5 35.0 12.0 5.2 3.1 2.4 3.1 8.9 10.7

5th percentile 6.7 1.9 3.0 11.1 17.0 8.7 2.8 2.2 1.9 2.0 2.6 10.3

Leesville Lake

95th percentile 230.0 257.0 272.0 250.0 225.0 194.0 116.9 87.4 133.0 127.0 206.4 246.1

75th percentile 111.4 108.4 138.0 139.8 105.7 65.2 32.0 15.7 12.0 22.0 124.0 136.0

mean 70.6 69.0 91.8 101.2 75.5 51.3 29.2 18.8 20.7 25.6 73.3 80.3

50th percentile 43.0 24.0 67.0 82.7 52.0 22.0 11.0 6.2 4.8 6.5 59.0 47.0

25th percentile 13.0 2.3 6.5 45.0 22.0 9.8 5.1 2.6 2.0 2.4 7.8 11.0

10th percentile 4.4 1.8 1.9 16.6 11.0 5.2 2.3 1.7 1.5 1.5 1.8 2.8

5th percentile 2.8 1.6 1.7 2.6 7.3 3.1 1.8 1.5 1.2 1.2 1.2 1.9

Tappan Lake

95th percentile 428.5 432.0 426.0 418.0 387.0 284.0 154.0 87.0 82.0 195.0 374.0 425.6

75th percentile 155.0 141.0 162.0 187.0 124.0 60.0 34.0 18.2 17.0 25.0 213.1 192.0

mean 103.7 94.9 110.6 127.7 102.9 64.5 35.9 25.3 23.4 35.9 126.1 120.7

50th percentile 50.0 17.0 51.0 68.0 56.5 30.2 16.0 8.9 6.1 10.4 98.0 60.3

25th percentile 14.0 2.8 5.6 33.0 30.0 16.0 7.8 3.0 2.4 3.4 12.1 12.0

10th percentile 4.5 2.0 2.1 3.3 16.0 7.3 2.9 1.7 1.7 2.0 2.8 3.5

5th percentile 2.2 1.5 1.4 1.7 3.8 3.1 1.8 1.0 1.2 1.6 2.1 2.3
Results and Discussion 15

Table 8. Statistics of daily mean flow-by amounts for indicated pumping rates and target minimum flow-by multiples for the Atwood, 

Leesville, and Tappan Lakes in the Muskingum River.

[ft3/s, cubic foot per second; Mgal/d, million gallons per day; target minimum flow-bys equal 1.5 ft3/s for Atwood and Leesville Lakes and 2.0 ft3/s for 

Tappan Lake] 

Statistic

Daily mean flow-by amounts, in ft3/s, for indicated lakes, pumping rates, and target minimum flow-by multiples

Pumping rate, in Mgal/d

1 2 3

Target minimum flow-by multiple

1 2 3 1 2 3 1 2 3

Atwood Lake

95th percentile 318.5 318.5 318.5 316.9 316.9 316.9 315.4 315.4 315.4

75th percentile 103.8 103.8 103.8 102.2 102.2 102.2 100.7 100.7 100.7

mean 83.9 84.0 84.0 82.5 82.6 82.6 81.1 81.2 81.3

50th percentile 51.3 51.3 51.3 49.8 49.8 49.8 48.2 48.2 48.2

25th percentile 11.5 11.5 11.5 9.9 9.9 9.9 8.4 8.4 8.4

10th percentile 4.7 4.7 4.7 3.1 3.1 4.5 1.6 3.0 4.5

5th percentile 1.5 2.6 2.6 1.5 2.6 2.6 1.5 2.6 2.6

Leesville Lake

95th percentile 217.1 217.1 217.1 215.6 215.6 215.6 214.0 214.0 214.0

75th percentile 86.5 86.5 86.5 84.9 84.9 84.9 83.4 83.4 83.4

mean 57.5 57.6 57.7 56.2 56.4 56.6 55.1 55.3 55.5

50th percentile 22.9 22.9 22.9 21.4 21.4 21.4 19.8 19.8 19.8

25th percentile 4.0 4.0 4.5 2.4 3.0 4.5 1.5 3.0 4.5

10th percentile 1.5 2.0 2.0 1.5 2.0 2.0 1.5 2.0 2.0

5th percentile 1.5 1.6 1.6 1.5 1.6 1.6 1.5 1.6 1.6

Tappan Lake

95th percentile 361.5 361.5 361.5 359.9 359.9 359.9 358.4 358.4 358.4

75th percentile 104.0 104.0 104.0 102.4 102.4 102.4 100.9 100.9 100.9

mean 79.4 79.5 79.6 78.2 78.4 78.5 77.0 77.2 77.4

50th percentile 24.1 24.1 24.1 22.5 22.5 22.5 21.0 21.0 21.0

25th percentile 5.9 5.9 6.0 4.4 4.4 6.0 2.8 4.0 6.0

10th percentile 2.0 2.2 2.2 2.0 2.2 2.2 2.0 2.2 2.2

5th percentile 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7
16 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

Table 9. Statistics of Atwood Lake, Ohio, daily mean flow-by amounts, by month, for indicated pumping rates and target minimum 

flow-by amounts.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Daily mean flow-by, in ft3/s, for indicated months and pump rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 1 Mgal/d

1.5

95th percentile 318.5 363.0 411.5 398.5 341.5 289.5 144.9 118.1 129.5 153.5 266.6 390.5

75th percentile 109.0 71.5 141.5 179.0 121.3 87.1 71.5 54.2 48.5 61.5 159.5 182.1

mean 82.6 72.8 107.0 144.4 108.5 82.3 52.7 40.0 42.0 46.0 109.1 120.7

50th percentile 30.5 14.5 74.5 98.3 74.5 60.5 43.4 19.7 16.2 23.5 96.5 66.2

25th percentile 16.5 9.2 9.7 70.6 54.1 26.5 9.5 6.3 6.7 9.6 40.5 20.5

10th percentile 9.1 1.5 8.5 34.0 33.5 10.5 3.7 1.5 1.5 1.6 7.4 9.2

5th percentile 5.2 1.5 1.5 9.5 15.5 7.2 1.5 1.5 1.5 1.5 1.5 8.7

3.0

95th percentile 318.5 363.0 411.5 398.5 341.5 289.5 144.9 118.1 129.5 153.5 266.6 390.5

75th percentile 109.0 71.5 141.5 179.0 121.3 87.1 71.5 54.2 48.5 61.5 159.5 182.1

mean 82.6 72.9 107.1 144.4 108.5 82.3 52.8 40.1 42.1 46.1 109.1 120.7

50th percentile 30.5 14.5 74.5 98.3 74.5 60.5 43.4 19.7 16.2 23.5 96.5 66.2

25th percentile 16.5 9.2 9.7 70.6 54.1 26.5 9.5 6.3 6.7 9.6 40.5 20.5

10th percentile 9.1 2.2 8.5 34.0 33.5 10.5 3.7 3.0 2.4 3.0 7.4 9.2

5th percentile 5.2 1.9 3.0 9.5 15.5 7.2 2.8 2.2 1.9 2.0 2.6 8.7

4.5

95th percentile 318.5 363.0 411.5 398.5 341.5 289.5 144.9 118.1 129.5 153.5 266.6 390.5

75th percentile 109.0 71.5 141.5 179.0 121.3 87.1 71.5 54.2 48.5 61.5 159.5 182.1

mean 82.6 72.9 107.1 144.4 108.5 82.3 52.8 40.2 42.2 46.1 109.2 120.7

50th percentile 30.5 14.5 74.5 98.3 74.5 60.5 43.4 19.7 16.2 23.5 96.5 66.2

25th percentile 16.5 9.2 9.7 70.6 54.1 26.5 9.5 6.3 6.7 9.6 40.5 20.5

10th percentile 9.1 2.2 8.5 34.0 33.5 10.5 4.5 3.1 2.4 3.1 7.4 9.2

5th percentile 5.2 1.9 3.0 9.5 15.5 7.2 2.8 2.2 1.9 2.0 2.6 8.7

Pumping rate = 2 Mgal/d

1.5

95th percentile 316.9 361.4 409.9 396.9 339.9 287.9 143.3 116.5 127.9 151.9 265.0 388.9

75th percentile 107.4 70.0 139.9 177.5 119.7 85.5 69.9 52.6 47.0 59.9 157.9 180.5

mean 81.1 71.5 105.6 142.8 106.9 80.8 51.3 38.7 40.7 44.6 107.6 119.2

50th percentile 28.9 12.9 72.9 96.8 72.9 58.9 41.9 18.1 14.6 21.9 94.9 64.7

25th percentile 14.9 7.6 8.1 69.0 52.6 24.9 7.9 4.7 5.1 8.1 38.9 18.9

10th percentile 7.5 1.5 6.9 32.4 31.9 8.9 2.1 1.5 1.5 1.5 5.8 7.6

5th percentile 3.6 1.5 1.5 8.0 13.9 5.6 1.5 1.5 1.5 1.5 1.5 7.2

3.0

95th percentile 316.9 361.4 409.9 396.9 339.9 287.9 143.3 116.5 127.9 151.9 265.0 388.9

75th percentile 107.4 70.0 139.9 177.5 119.7 85.5 69.9 52.6 47.0 59.9 157.9 180.5

mean 81.1 71.6 105.7 142.9 106.9 80.8 51.4 38.8 40.9 44.8 107.7 119.2

50th percentile 28.9 12.9 72.9 96.8 72.9 58.9 41.9 18.1 14.6 21.9 94.9 64.7

25th percentile 14.9 7.6 8.1 69.0 52.6 24.9 7.9 4.7 5.1 8.1 38.9 18.9

10th percentile 7.5 2.2 6.9 32.4 31.9 8.9 3.0 3.0 2.4 3.0 5.8 7.6

5th percentile 3.6 1.9 3.0 8.0 13.9 5.6 2.8 2.2 1.9 2.0 2.6 7.2
Results and Discussion 17

Table 9. Statistics of Atwood Lake, Ohio, daily mean flow-by amounts, by month, for indicated pumping rates and target minimum 

flow-by amounts.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Daily mean flow-by, in ft3/s, for indicated months and pump rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 2 Mgal/d—Continued

4.5

95th percentile 316.9 361.4 409.9 396.9 339.9 287.9 143.3 116.5 127.9 151.9 265.0 388.9

75th percentile 107.4 70.0 139.9 177.5 119.7 85.5 69.9 52.6 47.0 59.9 157.9 180.5

mean 81.2 71.6 105.7 142.9 107.0 80.8 51.5 39.0 41.0 44.8 107.8 119.2

50th percentile 28.9 12.9 72.9 96.8 72.9 58.9 41.9 18.1 14.6 21.9 94.9 64.7

25th percentile 14.9 7.6 8.1 69.0 52.6 24.9 7.9 4.7 5.1 8.1 38.9 18.9

10th percentile 7.5 2.2 6.9 32.4 31.9 8.9 4.5 3.1 2.4 3.1 5.8 7.6

5th percentile 4.5 1.9 3.0 8.0 13.9 5.6 2.8 2.2 1.9 2.0 2.6 7.2

Pumping rate = 3 Mgal/d

1.5

95th percentile 315.4 359.9 408.4 395.4 338.4 286.4 141.8 115.0 126.4 150.4 263.5 387.4

75th percentile 105.9 68.4 138.4 175.9 118.2 84.0 68.4 51.1 45.4 58.4 156.4 179.0

mean 79.6 70.2 104.2 141.3 105.4 79.2 49.9 37.4 39.5 43.3 106.2 117.7

50th percentile 27.4 11.4 71.4 95.2 71.4 57.4 40.3 16.6 13.1 20.4 93.4 63.1

25th percentile 13.4 6.1 6.6 67.5 51.0 23.4 6.4 3.2 3.6 6.5 37.4 17.4

10th percentile 6.0 1.5 5.4 30.9 30.4 7.4 1.5 1.5 1.5 1.5 4.3 6.1

5th percentile 2.1 1.5 1.5 6.4 12.4 4.1 1.5 1.5 1.5 1.5 1.5 5.7

3.0

95th percentile 315.4 359.9 408.4 395.4 338.4 286.4 141.8 115.0 126.4 150.4 263.5 387.4

75th percentile 105.9 68.4 138.4 175.9 118.2 84.0 68.4 51.1 45.4 58.4 156.4 179.0

mean 79.7 70.3 104.2 141.4 105.4 79.3 50.1 37.6 39.7 43.5 106.3 117.7

50th percentile 27.4 11.4 71.4 95.2 71.4 57.4 40.3 16.6 13.1 20.4 93.4 63.1

25th percentile 13.4 6.1 6.6 67.5 51.0 23.4 6.4 3.2 3.6 6.5 37.4 17.4

10th percentile 6.0 2.2 5.4 30.9 30.4 7.4 3.0 3.0 2.4 3.0 4.3 6.1

5th percentile 3.0 1.9 3.0 6.4 12.4 4.1 2.8 2.2 1.9 2.0 2.6 5.7

4.5

95th percentile 315.4 359.9 408.4 395.4 338.4 286.4 141.8 115.0 126.4 150.4 263.5 387.4

75th percentile 105.9 68.4 138.4 175.9 118.2 84.0 68.4 51.1 45.4 58.4 156.4 179.0

mean 79.7 70.3 104.3 141.4 105.4 79.3 50.2 37.8 39.8 43.6 106.4 117.7

50th percentile 27.4 11.4 71.4 95.2 71.4 57.4 40.3 16.6 13.1 20.4 93.4 63.1

25th percentile 13.4 6.1 6.6 67.5 51.0 23.4 6.4 4.5 4.5 6.5 37.4 17.4

10th percentile 6.0 2.2 5.4 30.9 30.4 7.4 4.5 3.1 2.4 3.1 4.5 6.1

5th percentile 4.5 1.9 3.0 6.4 12.4 4.5 2.8 2.2 1.9 2.0 2.6 5.7
18 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

Table 10. Statistics of Leesville Lake, Ohio, daily mean flow-by amounts, by month, for indicated pumping rates and target minimum 

flow-by amounts.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Daily mean flow-by, in ft3/s, for indicated months and pump rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 1 Mgal/d

1.5

95th percentile 228.5 255.5 270.5 248.5 223.4 192.5 115.3 85.8 131.5 125.5 204.9 244.5

75th percentile 109.9 106.8 136.5 138.3 104.2 63.7 30.5 14.1 10.5 20.5 122.5 134.5

mean 69.1 67.8 90.4 99.8 74.0 49.8 27.8 17.5 19.6 24.4 71.9 78.9

50th percentile 41.5 22.5 65.5 81.1 50.5 20.5 9.5 4.7 3.2 5.0 57.5 45.5

25th percentile 11.5 1.5 4.9 43.5 20.5 8.2 3.6 1.5 1.5 1.5 6.3 9.5

10th percentile 2.9 1.5 1.5 15.0 9.5 3.7 1.5 1.5 1.5 1.5 1.5 1.5

5th percentile 1.5 1.5 1.5 1.5 5.8 1.5 1.5 1.5 1.2 1.2 1.2 1.5

3.0

95th percentile 228.5 255.5 270.5 248.5 223.4 192.5 115.3 85.8 131.5 125.5 204.9 244.5

75th percentile 109.9 106.8 136.5 138.3 104.2 63.7 30.5 14.1 10.5 20.5 122.5 134.5

mean 69.2 68.0 90.5 99.8 74.0 49.8 27.9 17.8 19.8 24.6 72.0 78.9

50th percentile 41.5 22.5 65.5 81.1 50.5 20.5 9.5 4.7 3.2 5.0 57.5 45.5

25th percentile 11.5 2.3 4.9 43.5 20.5 8.2 3.6 2.6 2.0 2.4 6.3 9.5

10th percentile 3.0 1.8 1.9 15.0 9.5 3.7 2.3 1.7 1.5 1.5 1.8 2.8

5th percentile 2.8 1.6 1.7 2.6 5.8 3.0 1.8 1.5 1.2 1.2 1.2 1.9

4.5

95th percentile 228.5 255.5 270.5 248.5 223.4 192.5 115.3 85.8 131.5 125.5 204.9 244.5

75th percentile 109.9 106.8 136.5 138.3 104.2 63.7 30.5 14.1 10.5 20.5 122.5 134.5

mean 69.3 68.0 90.6 99.8 74.0 49.9 28.0 17.9 20.0 24.7 72.0 79.0

50th percentile 41.5 22.5 65.5 81.1 50.5 20.5 9.5 4.7 4.5 5.0 57.5 45.5

25th percentile 11.5 2.3 4.9 43.5 20.5 8.2 4.5 2.6 2.0 2.4 6.3 9.5

10th percentile 4.4 1.8 1.9 15.0 9.5 4.5 2.3 1.7 1.5 1.5 1.8 2.8

5th percentile 2.8 1.6 1.7 2.6 5.8 3.1 1.8 1.5 1.2 1.2 1.2 1.9

Pumping rate = 2 Mgal/d

1.5

95th percentile 226.9 253.9 268.9 246.9 221.9 190.9 113.8 84.3 129.9 123.9 203.3 243.0

75th percentile 108.3 105.3 134.9 136.7 102.6 62.1 28.9 12.6 8.9 18.9 120.9 132.9

mean 67.7 66.8 89.2 98.3 72.5 48.3 26.5 16.5 18.7 23.4 70.6 77.5

50th percentile 39.9 20.9 63.9 79.6 48.9 18.9 7.9 3.1 1.7 3.4 55.9 43.9

25th percentile 9.9 1.5 3.4 41.9 18.9 6.7 2.1 1.5 1.5 1.5 4.7 7.9

10th percentile 1.5 1.5 1.5 13.5 7.9 2.1 1.5 1.5 1.5 1.5 1.5 1.5

5th percentile 1.5 1.5 1.5 1.5 4.2 1.5 1.5 1.5 1.2 1.2 1.2 1.5

3.0

95th percentile 226.9 253.9 268.9 246.9 221.9 190.9 113.8 84.3 129.9 123.9 203.3 243.0

75th percentile 108.3 105.3 134.9 136.7 102.6 62.1 28.9 12.6 8.9 18.9 120.9 132.9

mean 67.9 67.0 89.3 98.3 72.5 48.4 26.8 16.9 19.1 23.7 70.7 77.7

50th percentile 39.9 20.9 63.9 79.6 48.9 18.9 7.9 3.1 3.0 3.4 55.9 43.9

25th percentile 9.9 2.3 3.4 41.9 18.9 6.7 3.0 2.6 2.0 2.4 4.7 7.9

10th percentile 3.0 1.8 1.9 13.5 7.9 3.0 2.3 1.7 1.5 1.5 1.8 2.8

5th percentile 2.8 1.6 1.7 2.6 4.2 3.0 1.8 1.5 1.2 1.2 1.2 1.9
Results and Discussion 19

Table 10. Statistics of Leesville Lake, Ohio, daily mean flow-by amounts, by month, for indicated pumping rates and target minimum 

flow-by amounts.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Daily mean flow-by, in ft3/s, for indicated months and pump rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 2 Mgal/d—Continued

4.5

95th percentile 226.9 253.9 268.9 246.9 221.9 190.9 113.8 84.3 129.9 123.9 203.3 243.0

75th percentile 108.3 105.3 134.9 136.7 102.6 62.1 28.9 12.6 8.9 18.9 120.9 132.9

mean 68.0 67.1 89.4 98.4 72.5 48.5 27.0 17.2 19.4 24.0 70.8 77.8

50th percentile 39.9 20.9 63.9 79.6 48.9 18.9 7.9 4.5 4.5 4.5 55.9 43.9

25th percentile 9.9 2.3 4.5 41.9 18.9 6.7 4.5 2.6 2.0 2.4 4.7 7.9

10th percentile 4.4 1.8 1.9 13.5 7.9 4.5 2.3 1.7 1.5 1.5 1.8 2.8

5th percentile 2.8 1.6 1.7 2.6 4.5 3.1 1.8 1.5 1.2 1.2 1.2 1.9

Pumping rate = 3 Mgal/d

1.5

95th percentile 225.4 252.4 267.4 245.4 220.3 189.4 112.2 82.7 128.4 122.4 201.8 241.5

75th percentile 106.8 103.7 133.4 135.2 101.1 60.6 27.4 11.0 7.4 17.4 119.4 131.4

mean 66.4 65.8 88.0 96.9 71.0 46.9 25.4 15.7 18.0 22.5 69.4 76.2

50th percentile 38.4 19.4 62.4 78.0 47.4 17.4 6.4 1.6 1.5 1.9 54.4 42.4

25th percentile 8.4 1.5 1.9 40.4 17.4 5.1 1.5 1.5 1.5 1.5 3.2 6.4

10th percentile 1.5 1.5 1.5 11.9 6.4 1.5 1.5 1.5 1.5 1.5 1.5 1.5

5th percentile 1.5 1.5 1.5 1.5 2.7 1.5 1.5 1.5 1.2 1.2 1.2 1.5

3.0

95th percentile 225.4 252.4 267.4 245.4 220.3 189.4 112.2 82.7 128.4 122.4 201.8 241.5

75th percentile 106.8 103.7 133.4 135.2 101.1 60.6 27.4 11.0 7.4 17.4 119.4 131.4

mean 66.6 66.1 88.2 96.9 71.0 47.1 25.7 16.2 18.5 23.0 69.5 76.4

50th percentile 38.4 19.4 62.4 78.0 47.4 17.4 6.4 3.0 3.0 3.0 54.4 42.4

25th percentile 8.4 2.3 3.0 40.4 17.4 5.1 3.0 2.6 2.0 2.4 3.2 6.4

10th percentile 3.0 1.8 1.9 11.9 6.4 3.0 2.3 1.7 1.5 1.5 1.8 2.8

5th percentile 2.8 1.6 1.7 2.6 3.0 3.0 1.8 1.5 1.2 1.2 1.2 1.9

4.5

95th percentile 225.4 252.4 267.4 245.4 220.3 189.4 112.2 82.7 128.4 122.4 201.8 241.5

75th percentile 106.8 103.7 133.4 135.2 101.1 60.6 27.4 11.0 7.4 17.4 119.4 131.4

mean 66.7 66.2 88.3 96.9 71.1 47.3 26.0 16.6 18.8 23.4 69.7 76.6

50th percentile 38.4 19.4 62.4 78.0 47.4 17.4 6.4 4.5 4.5 4.5 54.4 42.4

25th percentile 8.4 2.3 4.5 40.4 17.4 5.1 4.5 2.6 2.0 2.4 4.5 6.4

10th percentile 4.4 1.8 1.9 11.9 6.4 4.5 2.3 1.7 1.5 1.5 1.8 2.8

5th percentile 2.8 1.6 1.7 2.6 4.5 3.1 1.8 1.5 1.2 1.2 1.2 1.9
20 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

Table 11. Statistics of Tappan Lake, Ohio, daily mean flow-by amounts, by month, for indicated pumping rates and target minimum 

flow-by amounts.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Daily mean flow-by, in ft3/s, for indicated months and pump rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 1 Mgal/d

2.0

95th percentile 427.0 430.5 424.5 416.5 385.5 282.5 152.5 85.5 80.5 193.5 372.5 424.0

75th percentile 153.5 139.5 160.5 185.5 122.5 58.5 32.5 16.7 15.5 23.5 211.6 190.5

mean 102.2 93.7 109.3 126.2 101.4 63.0 34.5 24.1 22.3 34.7 124.7 119.3

50th percentile 48.5 15.4 49.5 66.5 54.9 28.6 14.5 7.4 4.5 8.8 96.5 58.7

25th percentile 12.5 2.0 4.1 31.5 28.5 14.5 6.3 2.0 2.0 2.0 10.5 10.5

10th percentile 3.0 2.0 2.0 2.0 14.5 5.8 2.0 1.7 1.7 2.0 2.0 2.0

5th percentile 2.0 1.5 1.4 1.7 2.3 2.0 1.8 1.0 1.2 1.6 2.0 2.0

3.0

95th percentile 427.0 430.5 424.5 416.5 385.5 282.5 152.5 85.5 80.5 193.5 372.5 424.0

75th percentile 153.5 139.5 160.5 185.5 122.5 58.5 32.5 16.7 15.5 23.5 211.6 190.5

mean 102.3 93.8 109.4 126.3 101.4 63.0 34.6 24.3 22.6 34.8 124.8 119.4

50th percentile 48.5 15.4 49.5 66.5 54.9 28.6 14.5 7.4 4.5 8.8 96.5 58.7

25th percentile 12.5 2.8 4.1 31.5 28.5 14.5 6.3 3.0 2.4 3.4 10.5 10.5

10th percentile 4.0 2.0 2.1 3.3 14.5 5.8 2.9 1.7 1.7 2.0 2.8 3.5

5th percentile 2.2 1.5 1.4 1.7 3.8 3.1 1.8 1.0 1.2 1.6 2.1 2.3

6.0

95th percentile 427.0 430.5 424.5 416.5 385.5 282.5 152.5 85.5 80.5 193.5 372.5 424.0

75th percentile 153.5 139.5 160.5 185.5 122.5 58.5 32.5 16.7 15.5 23.5 211.6 190.5

mean 102.4 93.8 109.4 126.3 101.4 63.1 34.7 24.4 22.7 34.9 124.8 119.4

50th percentile 48.5 15.4 49.5 66.5 54.9 28.6 14.5 7.4 6.0 8.8 96.5 58.7

25th percentile 12.5 2.8 5.6 31.5 28.5 14.5 6.3 3.0 2.4 3.4 10.5 10.5

10th percentile 4.5 2.0 2.1 3.3 14.5 6.0 2.9 1.7 1.7 2.0 2.8 3.5

5th percentile 2.2 1.5 1.4 1.7 3.8 3.1 1.8 1.0 1.2 1.6 2.1 2.3

Pumping rate = 2 Mgal/d

2.0

95th percentile 425.4 428.9 422.9 414.9 383.9 280.9 150.9 83.9 78.9 191.9 370.9 422.5

75th percentile 151.9 137.9 158.9 183.9 120.9 56.9 30.9 15.1 13.9 21.9 210.0 188.9

mean 100.9 92.6 108.1 124.9 99.9 61.5 33.2 23.0 21.4 33.6 123.4 117.9

50th percentile 46.9 13.9 47.9 64.9 53.4 27.1 12.9 5.8 3.0 7.3 94.9 57.2

25th percentile 10.9 2.0 2.5 29.9 26.9 12.9 4.7 2.0 2.0 2.0 9.0 8.9

10th percentile 2.0 2.0 2.0 2.0 12.9 4.2 2.0 1.7 1.7 2.0 2.0 2.0

5th percentile 2.0 1.5 1.4 1.7 2.0 2.0 1.8 1.0 1.2 1.6 2.0 2.0

3.0

95th percentile 425.4 428.9 422.9 414.9 383.9 280.9 150.9 83.9 78.9 191.9 370.9 422.5

75th percentile 151.9 137.9 158.9 183.9 120.9 56.9 30.9 15.1 13.9 21.9 210.0 188.9

mean 101.0 92.7 108.2 124.9 99.9 61.6 33.4 23.4 21.8 33.8 123.5 118.1

50th percentile 46.9 13.9 47.9 64.9 53.4 27.1 12.9 5.8 4.0 7.3 94.9 57.2

25th percentile 10.9 2.8 4.0 29.9 26.9 12.9 4.7 3.0 2.4 3.4 9.0 8.9

10th percentile 4.0 2.0 2.1 3.3 12.9 4.2 2.9 1.7 1.7 2.0 2.8 3.5

5th percentile 2.2 1.5 1.4 1.7 3.8 3.1 1.8 1.0 1.2 1.6 2.1 2.3
Results and Discussion 21

Table 11. Statistics of Tappan Lake, Ohio, daily mean flow-by amounts, by month, for indicated pumping rates and target minimum 

flow-by amounts.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Daily mean flow-by, in ft3/s, for indicated months and pump rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 2 Mgal/d—Continued

6.0

95th percentile 425.4 428.9 422.9 414.9 383.9 280.9 150.9 83.9 78.9 191.9 370.9 422.5

75th percentile 151.9 137.9 158.9 183.9 120.9 56.9 30.9 15.1 13.9 21.9 210.0 188.9

mean 101.0 92.8 108.3 125.0 100.0 61.7 33.6 23.6 22.0 34.1 123.6 118.2

50th percentile 46.9 13.9 47.9 64.9 53.4 27.1 12.9 6.0 6.0 7.3 94.9 57.2

25th percentile 10.9 2.8 5.6 29.9 26.9 12.9 6.0 3.0 2.4 3.4 9.0 8.9

10th percentile 4.5 2.0 2.1 3.3 12.9 6.0 2.9 1.7 1.7 2.0 2.8 3.5

5th percentile 2.2 1.5 1.4 1.7 3.8 3.1 1.8 1.0 1.2 1.6 2.1 2.3

Pumping rate = 3 Mgal/d

2.0

95th percentile 423.9 427.4 421.4 413.4 382.4 279.4 149.4 82.4 77.4 190.4 369.4 420.9

75th percentile 150.4 136.4 157.4 182.4 119.4 55.4 29.4 13.6 12.4 20.4 208.5 187.4

mean 99.5 91.5 106.9 123.5 98.5 60.1 31.9 22.1 20.6 32.6 122.1 116.6

50th percentile 45.4 12.3 46.4 63.4 51.8 25.6 11.4 4.3 2.0 5.7 93.4 55.6

25th percentile 9.4 2.0 2.0 28.4 25.4 11.4 3.2 2.0 2.0 2.0 7.4 7.4

10th percentile 2.0 2.0 2.0 2.0 11.4 2.7 2.0 1.7 1.7 2.0 2.0 2.0

5th percentile 2.0 1.5 1.4 1.7 2.0 2.0 1.8 1.0 1.2 1.6 2.0 2.0

3.0

95th percentile 423.9 427.4 421.4 413.4 382.4 279.4 149.4 82.4 77.4 190.4 369.4 420.9

75th percentile 150.4 136.4 157.4 182.4 119.4 55.4 29.4 13.6 12.4 20.4 208.5 187.4

mean 99.7 91.7 107.1 123.6 98.5 60.2 32.2 22.5 21.1 32.9 122.3 116.8

50th percentile 45.4 12.3 46.4 63.4 51.8 25.6 11.4 4.3 4.0 5.7 93.4 55.6

25th percentile 9.4 2.8 4.0 28.4 25.4 11.4 4.0 3.0 2.4 3.4 7.4 7.4

10th percentile 4.0 2.0 2.1 3.3 11.4 4.0 2.9 1.7 1.7 2.0 2.8 3.5

5th percentile 2.2 1.5 1.4 1.7 3.8 3.1 1.8 1.0 1.2 1.6 2.1 2.3

6.0

95th percentile 423.9 427.4 421.4 413.4 382.4 279.4 149.4 82.4 77.4 190.4 369.4 420.9

75th percentile 150.4 136.4 157.4 182.4 119.4 55.4 29.4 13.6 12.4 20.4 208.5 187.4

mean 99.8 91.7 107.2 123.6 98.5 60.4 32.5 22.9 21.4 33.3 122.4 116.9

50th percentile 45.4 12.3 46.4 63.4 51.8 25.6 11.4 6.0 6.0 6.0 93.4 55.6

25th percentile 9.4 2.8 5.6 28.4 25.4 11.4 6.0 3.0 2.4 3.4 7.4 7.4

10th percentile 4.5 2.0 2.1 3.3 11.4 6.0 2.9 1.7 1.7 2.0 2.8 3.5

5th percentile 2.2 1.5 1.4 1.7 3.8 3.1 1.8 1.0 1.2 1.6 2.1 2.3
22 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

Table 12 shows the computed aggregate analytical-period 

flow-by statistics from table 8 reported as a percentage of the 

corresponding observed outflow statistics from table 6. The 

cells of table 12 have been color-coded according to a gradient, where the maximum value in the table (100 percent) is 

colored dark green and the minimum value (27.3 percent) is 

colored red. Values that lie between these two extremes are 

graded in color from light green to dark orange as a function of their magnitude. The objective of coloring the table 

cells is to make it easier to visualize the conditions and flow 

percentiles that deviate most from the corresponding observed 

outflow statistics. Clearly, with the exception of some of 

the lower percentiles (10 percent and smaller), the flow-by 

amounts tend to represent an increasingly smaller proportion of the observed outflows as pumping rates are increased. 

Increasing the target minimum flow-by amount mitigates 

the effect of increased pumping for some order statistics. 

The reason that some low-percentile flow-by amounts were 

unchanged from observed outflows after increases in pump 

capacities and target minimum flow-by amounts is that the 

observed outflows were already less than or equal to the smallest flow-by amount considered, so no additional water was 

available for pumping and (or) to be reserved as flow-by.

Tables 13–15 show the computed monthly flow-by 

statistics from tables 9–11 reported as percentages of the corresponding observed outflow statistics from table 7. Similar to 

table 12, the cells in these tables have been colored-coded according to a gradient, where the maximum value in each table 

is colored dark green and the minimum value is colored red. 

As was observed with the aggregate analytical-period results 

(table 12), with the exception of some of the lower percentiles, 

the monthly flow-by amounts tend to represent an increasingly smaller proportion of the observed outflows as pumping 

rates are increased. Clearly, for some order statistics, flow-by 

amounts tend to represent proportionally smaller amounts of 

the observed outflows in certain months (for example, July–

October) than in others. Increasing flow-by amounts mitigate 

some of these reductions in flow; however, that mitigation 

comes at the expense of smaller potential withdrawals. 

Mass-curve data are reported for the Atwood, Leesville, 

and Tappan Lakes in appendix 1 (table 1-1). Figure 3 shows 

an example plot of the surplus-water mass curves for the 

Atwood, Leesville, and Tappan Lakes based on current target 

minimum outflows. The mass curve for Atwood Lake is based 

on 51 years of data whereas the mass curves for Leesville and 

Tappan Lakes are each based on 73 years of data. The slope of 

a line that connects the first and last point on a mass curve for 

a given lake in figure 3 represents the average daily surpluswater volume for that lake. It is evident from figure 3 that the 

Leesville Lake has an average daily surplus-water volume that 

is considerably smaller than that of the Atwood and Tappan 

Lakes. That seems reasonable given that the drainage area 

of the Leesville Lake is considerably smaller than that of the 

Atwood and Tappan Lakes.

Limitations 

Direct use of the data presented in this report to make decisions about future water uses requires assumptions about the 

extent to which historical outflow characteristics will be representative of future outflow characteristics. Those assumptions 

could be in error depending on the degree to which there are 

changes in future climate or other factors that affect inflows to, 

or water losses from, the lakes. 

Computed withdrawals represent maximum values given 

the combination of pumping rate and target minimum flow-by 

amounts, and assume that the observed outflow data are accurate. The ability to actually capture these maximum withdrawals will depend on how the pumps are operated, the maximum 

amount of storage for pumped water, and on the rate and (or) 

timing of removal of water from storage.

The term “surplus water,” as used in this report, is not 

meant to imply judgment about the value of the water for any 

particular use, but is used merely to signify the amount of water 

that potentially is available for withdrawal while still meeting the 

minimum flow-by target immediately downstream from the lake. 
Limitations 23

Table 12. Daily mean flow-by statistics for the Atwood, Leesville, and Tappan Lakes, Muskingum River Watershed, Ohio, expressed 

as a percentage of observed outflow statistics.

[Mgal/d, million gallons per day; minimum in-stream flow targets equal 1.5 cubic feet per second (ft3/s) for Atwood and Leesville Lakes and 2.0 ft3/s for 

Tappan Lake; color scale is gradient from maximum value, in green, to minimum value, in red]

Statistic

Daily mean flow-by amounts expressed as a percentage of observed outflow statistics, for indicated lakes, 

pumping rates, and minimum in-stream flow-target multiples

Pumping rate, in Mgal/d

1 2 3

Minimum in-stream flow-target multiple

1 2 3 1 2 3 1 2 3

Atwood Lake

95th percentile 99.5% 99.5% 99.5% 99.0% 99.0% 99.0% 98.5% 98.5% 98.5%

75th percentile 98.5% 98.5% 98.5% 97.1% 97.1% 97.1% 95.6% 95.6% 95.6%

mean 98.3% 98.3% 98.4% 96.6% 96.7% 96.7% 94.9% 95.1% 95.1%

50th percentile 97.1% 97.1% 97.1% 94.1% 94.1% 94.1% 91.2% 91.2% 91.2%

25th percentile 88.1% 88.1% 88.1% 76.2% 76.2% 76.2% 64.3% 64.3% 64.3%

10th percentile 75.0% 75.0% 75.0% 50.1% 50.1% 72.6% 25.1% 48.4% 72.6%

5th percentile 57.7% 100.0% 100.0% 57.7% 100.0% 100.0% 57.7% 100.0% 100.0%

Leesville Lake

95th percentile 99.3% 99.3% 99.3% 98.6% 98.6% 98.6% 97.9% 97.9% 97.9%

75th percentile 98.2% 98.2% 98.2% 96.5% 96.5% 96.5% 94.7% 94.7% 94.7%

mean 97.7% 97.9% 98.0% 95.6% 95.9% 96.1% 93.6% 94.0% 94.4%

50th percentile 93.7% 93.7% 93.7% 87.3% 87.3% 87.3% 81.0% 81.0% 81.0%

25th percentile 71.9% 71.9% 81.8% 43.7% 54.5% 81.8% 27.3% 54.5% 81.8%

10th percentile 75.0% 100.0% 100.0% 75.0% 100.0% 100.0% 75.0% 100.0% 100.0%

5th percentile 93.8% 100.0% 100.0% 93.8% 100.0% 100.0% 93.8% 100.0% 100.0%

Tappan Lake

95th percentile 99.6% 99.6% 99.6% 99.1% 99.1% 99.1% 98.7% 98.7% 98.7%

75th percentile 98.5% 98.5% 98.5% 97.1% 97.1% 97.1% 95.6% 95.6% 95.6%

mean 98.3% 98.5% 98.5% 96.8% 97.0% 97.1% 95.3% 95.6% 95.8%

50th percentile 94.0% 94.0% 94.0% 87.9% 87.9% 87.9% 81.9% 81.9% 81.9%

25th percentile 79.3% 79.3% 80.2% 58.6% 58.6% 80.2% 38.0% 53.5% 80.2%

10th percentile 90.9% 100.0% 100.0% 90.9% 100.0% 100.0% 90.9% 100.0% 100.0%

5th percentile 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
24 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

Table 13. Monthly statistics of Atwood Lake, Ohio, daily mean flow-by amounts for indicated pumping rates and target minimum 

flow-by amounts, expressed as a percentage of corresponding statistic based on observed outflows.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day; color scale is gradient from maximum value, in green, to minimum value, in red]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Daily mean flow-by amounts expressed as a percentage of observed outflow statistics, 

for indicated months and pumping rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 1 Mgal/d

1.5

95th percentile 99.5% 99.6% 99.6% 99.6% 99.5% 99.5% 98.9% 98.7% 98.8% 99.0% 99.4% 99.6%

75th percentile 98.6% 97.9% 98.9% 99.1% 98.7% 98.3% 97.9% 97.2% 96.9% 97.5% 99.0% 99.2%

mean 98.2% 98.1% 98.6% 98.9% 98.6% 98.2% 97.3% 96.5% 96.8% 97.0% 98.7% 98.8%

50th percentile 95.2% 90.3% 98.0% 98.5% 98.0% 97.5% 96.6% 92.7% 91.3% 93.8% 98.4% 97.7%

25th percentile 91.4% 85.6% 86.2% 97.9% 97.2% 94.5% 85.9% 80.2% 81.1% 86.2% 96.3% 93.0%

10th percentile 85.4% 68.2% 84.5% 95.6% 95.6% 87.1% 70.2% 49.8% 62.5% 50.1% 82.6% 85.6%

5th percentile 76.9% 78.9% 50.0% 86.0% 90.9% 82.2% 53.6% 68.2% 78.9% 75.0% 57.7% 85.0%

3.0

95th percentile 99.5% 99.6% 99.6% 99.6% 99.5% 99.5% 98.9% 98.7% 98.8% 99.0% 99.4% 99.6%

75th percentile 98.6% 97.9% 98.9% 99.1% 98.7% 98.3% 97.9% 97.2% 96.9% 97.5% 99.0% 99.2%

mean 98.2% 98.2% 98.7% 99.0% 98.6% 98.2% 97.3% 96.7% 97.0% 97.2% 98.7% 98.8%

50th percentile 95.2% 90.3% 98.0% 98.5% 98.0% 97.5% 96.6% 92.7% 91.3% 93.8% 98.4% 97.7%

25th percentile 91.4% 85.6% 86.2% 97.9% 97.2% 94.5% 85.9% 80.2% 81.1% 86.2% 96.3% 93.0%

10th percentile 85.4% 100.0% 84.5% 95.6% 95.6% 87.1% 70.2% 98.0% 100.0% 96.8% 82.6% 85.6%

5th percentile 76.9% 100.0% 100.0% 86.0% 90.9% 82.2% 100.0% 100.0% 100.0% 100.0% 100.0% 85.0%

4.5

95th percentile 99.5% 99.6% 99.6% 99.6% 99.5% 99.5% 98.9% 98.7% 98.8% 99.0% 99.4% 99.6%

75th percentile 98.6% 97.9% 98.9% 99.1% 98.7% 98.3% 97.9% 97.2% 96.9% 97.5% 99.0% 99.2%

mean 98.2% 98.2% 98.7% 99.0% 98.6% 98.2% 97.4% 96.9% 97.1% 97.3% 98.7% 98.8%

50th percentile 95.2% 90.3% 98.0% 98.5% 98.0% 97.5% 96.6% 92.7% 91.3% 93.8% 98.4% 97.7%

25th percentile 91.4% 85.6% 86.2% 97.9% 97.2% 94.5% 85.9% 80.2% 81.1% 86.2% 96.3% 93.0%

10th percentile 85.4% 100.0% 84.5% 95.6% 95.6% 87.1% 86.5% 100.0% 100.0% 100.0% 82.6% 85.6%

5th percentile 76.9% 100.0% 100.0% 86.0% 90.9% 82.2% 100.0% 100.0% 100.0% 100.0% 100.0% 85.0%

Pumping rate = 2 Mgal/d

1.5

95th percentile 99.0% 99.2% 99.3% 99.2% 99.1% 98.9% 97.9% 97.4% 97.6% 98.0% 98.8% 99.2%

75th percentile 97.2% 95.8% 97.8% 98.3% 97.5% 96.5% 95.8% 94.4% 93.8% 95.1% 98.1% 98.3%

mean 96.4% 96.3% 97.3% 97.9% 97.2% 96.3% 94.6% 93.2% 93.8% 94.1% 97.4% 97.5%

50th percentile 90.3% 80.7% 95.9% 96.9% 95.9% 95.0% 93.1% 85.4% 82.5% 87.6% 96.8% 95.4%

25th percentile 82.8% 71.1% 72.4% 95.7% 94.4% 88.9% 71.9% 60.3% 62.3% 72.3% 92.6% 85.9%

10th percentile 70.8% 68.2% 69.1% 91.3% 91.2% 74.2% 40.5% 49.0% 62.5% 48.4% 65.2% 71.2%

5th percentile 53.8% 78.9% 50.0% 72.1% 81.8% 64.4% 53.6% 68.2% 78.9% 75.0% 57.7% 69.9%

3.0

95th percentile 99.0% 99.2% 99.3% 99.2% 99.1% 98.9% 97.9% 97.4% 97.6% 98.0% 98.8% 99.2%

75th percentile 97.2% 95.8% 97.8% 98.3% 97.5% 96.5% 95.8% 94.4% 93.8% 95.1% 98.1% 98.3%

mean 96.5% 96.5% 97.4% 97.9% 97.2% 96.4% 94.8% 93.6% 94.2% 94.4% 97.4% 97.6%

50th percentile 90.3% 80.7% 95.9% 96.9% 95.9% 95.0% 93.1% 85.4% 82.5% 87.6% 96.8% 95.4%

25th percentile 82.8% 71.1% 72.4% 95.7% 94.4% 88.9% 71.9% 60.3% 62.3% 72.3% 92.6% 85.9%

10th percentile 70.8% 100.0% 69.1% 91.3% 91.2% 74.2% 57.7% 98.0% 100.0% 96.8% 65.2% 71.2%

5th percentile 53.8% 100.0% 100.0% 72.1% 81.8% 64.4% 100.0% 100.0% 100.0% 100.0% 100.0% 69.9%
Limitations 25

Table 13. Monthly statistics of Atwood Lake, Ohio, daily mean flow-by amounts for indicated pumping rates and target minimum 

flow-by amounts, expressed as a percentage of corresponding statistic based on observed outflows.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day; color scale is gradient from maximum value, in green, to minimum value, in red]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Daily mean flow-by amounts expressed as a percentage of observed outflow statistics, 

for indicated months and pumping rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 2 Mgal/d—Continued

4.5

95th percentile 99.0% 99.2% 99.3% 99.2% 99.1% 98.9% 97.9% 97.4% 97.6% 98.0% 98.8% 99.2%

75th percentile 97.2% 95.8% 97.8% 98.3% 97.5% 96.5% 95.8% 94.4% 93.8% 95.1% 98.1% 98.3%

mean 96.5% 96.5% 97.4% 97.9% 97.2% 96.4% 95.0% 93.9% 94.4% 94.6% 97.5% 97.6%

50th percentile 90.3% 80.7% 95.9% 96.9% 95.9% 95.0% 93.1% 85.4% 82.5% 87.6% 96.8% 95.4%

25th percentile 82.8% 71.1% 72.4% 95.7% 94.4% 88.9% 71.9% 60.3% 62.3% 72.3% 92.6% 85.9%

10th percentile 70.8% 100.0% 69.1% 91.3% 91.2% 74.2% 86.5% 100.0% 100.0% 100.0% 65.2% 71.2%

5th percentile 67.2% 100.0% 100.0% 72.1% 81.8% 64.4% 100.0% 100.0% 100.0% 100.0% 100.0% 69.9%

Pumping rate = 3 Mgal/d

1.5

95th percentile 98.5% 98.7% 98.9% 98.8% 98.6% 98.4% 96.8% 96.1% 96.5% 97.0% 98.3% 98.8%

75th percentile 95.8% 93.6% 96.8% 97.4% 96.2% 94.8% 93.6% 91.7% 90.7% 92.6% 97.1% 97.5%

mean 94.6% 94.6% 96.0% 96.9% 95.8% 94.5% 92.0% 90.1% 90.9% 91.4% 96.1% 96.3%

50th percentile 85.5% 71.0% 93.9% 95.4% 93.9% 92.5% 89.7% 78.1% 73.8% 81.4% 95.3% 93.1%

25th percentile 74.2% 56.7% 58.6% 93.6% 91.7% 83.4% 57.8% 40.5% 43.4% 58.5% 88.9% 78.9%

10th percentile 56.3% 68.2% 53.6% 86.9% 86.7% 61.3% 28.8% 49.0% 62.5% 48.4% 47.8% 56.7%

5th percentile 30.7% 78.9% 50.0% 58.1% 72.7% 46.6% 53.6% 68.2% 78.9% 75.0% 57.7% 54.9%

3.0

95th percentile 98.5% 98.7% 98.9% 98.8% 98.6% 98.4% 96.8% 96.1% 96.5% 97.0% 98.3% 98.8%

75th percentile 95.8% 93.6% 96.8% 97.4% 96.2% 94.8% 93.6% 91.7% 90.7% 92.6% 97.1% 97.5%

mean 94.7% 94.7% 96.1% 96.9% 95.8% 94.6% 92.3% 90.7% 91.4% 91.7% 96.2% 96.4%

50th percentile 85.5% 71.0% 93.9% 95.4% 93.9% 92.5% 89.7% 78.1% 73.8% 81.4% 95.3% 93.1%

25th percentile 74.2% 56.7% 58.6% 93.6% 91.7% 83.4% 57.8% 40.5% 43.4% 58.5% 88.9% 78.9%

10th percentile 56.3% 100.0% 53.6% 86.9% 86.7% 61.3% 57.7% 98.0% 100.0% 96.8% 47.8% 56.7%

5th percentile 44.8% 100.0% 100.0% 58.1% 72.7% 46.6% 100.0% 100.0% 100.0% 100.0% 100.0% 54.9%

4.5

95th percentile 98.5% 98.7% 98.9% 98.8% 98.6% 98.4% 96.8% 96.1% 96.5% 97.0% 98.3% 98.8%

75th percentile 95.8% 93.6% 96.8% 97.4% 96.2% 94.8% 93.6% 91.7% 90.7% 92.6% 97.1% 97.5%

mean 94.8% 94.8% 96.1% 96.9% 95.8% 94.6% 92.7% 91.2% 91.7% 91.9% 96.2% 96.4%

50th percentile 85.5% 71.0% 93.9% 95.4% 93.9% 92.5% 89.7% 78.1% 73.8% 81.4% 95.3% 93.1%

25th percentile 74.2% 56.7% 58.6% 93.6% 91.7% 83.4% 57.8% 57.7% 54.9% 58.5% 88.9% 78.9%

10th percentile 56.3% 100.0% 53.6% 86.9% 86.7% 61.3% 86.5% 100.0% 100.0% 100.0% 50.6% 56.7%

5th percentile 67.2% 100.0% 100.0% 58.1% 72.7% 51.7% 100.0% 100.0% 100.0% 100.0% 100.0% 54.9%
26 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

Table 14. Monthly statistics of Leesville Lake, Ohio, daily mean flow-by amounts for indicated pumping rates and target minimum 

flow-by amounts, expressed as a percentage of corresponding statistic based on observed outflows.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day; color scale is gradient from maximum value, in green, to minimum value, in red]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Daily mean flow-by amounts expressed as a percentage of observed outflow statistics, 

for indicated months and pumping rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 1 Mgal/d

1.5

95th percentile 99.3% 99.4% 99.4% 99.4% 99.3% 99.2% 98.7% 98.2% 98.8% 98.8% 99.3% 99.4%

75th percentile 98.6% 98.6% 98.9% 98.9% 98.5% 97.6% 95.2% 90.1% 87.1% 93.0% 98.8% 98.9%

mean 97.9% 98.2% 98.5% 98.5% 98.0% 97.1% 95.2% 93.4% 94.6% 95.3% 98.1% 98.2%

50th percentile 96.4% 93.6% 97.7% 98.1% 97.0% 93.0% 85.9% 75.0% 67.5% 76.2% 97.4% 96.7%

25th percentile 88.1% 64.4% 76.2% 96.6% 93.0% 84.2% 70.0% 57.7% 75.0% 62.5% 80.2% 85.9%

10th percentile 64.8% 83.3% 78.9% 90.7% 85.9% 70.5% 65.2% 88.2% 100.0% 100.0% 83.3% 53.6%

5th percentile 53.6% 93.8% 88.2% 57.7% 78.8% 49.4% 83.3% 100.0% 100.0% 100.0% 100.0% 78.1%

3.0

95th percentile 99.3% 99.4% 99.4% 99.4% 99.3% 99.2% 98.7% 98.2% 98.8% 98.8% 99.3% 99.4%

75th percentile 98.6% 98.6% 98.9% 98.9% 98.5% 97.6% 95.2% 90.1% 87.1% 93.0% 98.8% 98.9%

mean 98.0% 98.5% 98.7% 98.6% 98.0% 97.2% 95.7% 94.5% 95.8% 96.0% 98.3% 98.3%

50th percentile 96.4% 93.6% 97.7% 98.1% 97.0% 93.0% 85.9% 75.0% 67.5% 76.2% 97.4% 96.7%

25th percentile 88.1% 100.0% 76.2% 96.6% 93.0% 84.2% 70.0% 100.0% 100.0% 100.0% 80.2% 85.9%

10th percentile 68.2% 100.0% 100.0% 90.7% 85.9% 70.5% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

5th percentile 100.0% 100.0% 100.0% 100.0% 78.8% 98.1% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

4.5

95th percentile 99.3% 99.4% 99.4% 99.4% 99.3% 99.2% 98.7% 98.2% 98.8% 98.8% 99.3% 99.4%

75th percentile 98.6% 98.6% 98.9% 98.9% 98.5% 97.6% 95.2% 90.1% 87.1% 93.0% 98.8% 98.9%

mean 98.1% 98.6% 98.7% 98.6% 98.0% 97.3% 96.1% 95.4% 96.5% 96.6% 98.3% 98.4%

50th percentile 96.4% 93.6% 97.7% 98.1% 97.0% 93.0% 85.9% 75.0% 94.7% 76.2% 97.4% 96.7%

25th percentile 88.1% 100.0% 76.2% 96.6% 93.0% 84.2% 87.4% 100.0% 100.0% 100.0% 80.2% 85.9%

10th percentile 100.0% 100.0% 100.0% 90.7% 85.9% 85.8% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

5th percentile 100.0% 100.0% 100.0% 100.0% 78.8% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

Pumping rate = 2 Mgal/d

1.5

95th percentile 98.7% 98.8% 98.9% 98.8% 98.6% 98.4% 97.4% 96.5% 97.7% 97.6% 98.5% 98.7%

75th percentile 97.2% 97.1% 97.8% 97.8% 97.1% 95.3% 90.3% 80.2% 74.2% 85.9% 97.5% 97.7%

mean 95.9% 96.7% 97.2% 97.1% 96.1% 94.3% 90.9% 87.9% 90.4% 91.4% 96.4% 96.5%

50th percentile 92.8% 87.1% 95.4% 96.3% 94.0% 85.9% 71.9% 50.1% 34.9% 52.4% 94.8% 93.4%

25th percentile 76.2% 64.4% 52.4% 93.1% 85.9% 68.3% 39.9% 57.7% 75.0% 62.5% 60.3% 71.9%

10th percentile 34.1% 83.3% 78.9% 81.3% 71.9% 41.0% 65.2% 88.2% 100.0% 100.0% 83.3% 53.6%

5th percentile 53.6% 93.8% 88.2% 57.7% 57.6% 49.1% 83.3% 100.0% 100.0% 100.0% 100.0% 78.1%

3.0

95th percentile 98.7% 98.8% 98.9% 98.8% 98.6% 98.4% 97.4% 96.5% 97.7% 97.6% 98.5% 98.7%

75th percentile 97.2% 97.1% 97.8% 97.8% 97.1% 95.3% 90.3% 80.2% 74.2% 85.9% 97.5% 97.7%

mean 96.1% 97.1% 97.4% 97.1% 96.1% 94.5% 91.7% 90.0% 92.3% 92.6% 96.6% 96.7%

50th percentile 92.8% 87.1% 95.4% 96.3% 94.0% 85.9% 71.9% 50.1% 63.1% 52.4% 94.8% 93.4%

25th percentile 76.2% 100.0% 52.4% 93.1% 85.9% 68.3% 58.3% 100.0% 100.0% 100.0% 60.3% 71.9%

10th percentile 68.2% 100.0% 100.0% 81.3% 71.9% 57.2% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

5th percentile 100.0% 100.0% 100.0% 100.0% 57.6% 98.1% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
Limitations 27

Table 14. Monthly statistics of Leesville Lake, Ohio, daily mean flow-by amounts for indicated pumping rates and target minimum 

flow-by amounts, expressed as a percentage of corresponding statistic based on observed outflows.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day; color scale is gradient from maximum value, in green, to minimum value, in red]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Daily mean flow-by amounts expressed as a percentage of observed outflow statistics, 

for indicated months and pumping rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 2 Mgal/d—Continued

4.5

95th percentile 98.7% 98.8% 98.9% 98.8% 98.6% 98.4% 97.4% 96.5% 97.7% 97.6% 98.5% 98.7%

75th percentile 97.2% 97.1% 97.8% 97.8% 97.1% 95.3% 90.3% 80.2% 74.2% 85.9% 97.5% 97.7%

mean 96.2% 97.2% 97.4% 97.1% 96.1% 94.7% 92.5% 91.5% 93.5% 93.6% 96.7% 96.9%

50th percentile 92.8% 87.1% 95.4% 96.3% 94.0% 85.9% 71.9% 72.6% 94.7% 69.2% 94.8% 93.4%

25th percentile 76.2% 100.0% 69.3% 93.1% 85.9% 68.3% 87.4% 100.0% 100.0% 100.0% 60.3% 71.9%

10th percentile 100.0% 100.0% 100.0% 81.3% 71.9% 85.8% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

5th percentile 100.0% 100.0% 100.0% 100.0% 61.6% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

Pumping rate = 3 Mgal/d

1.5

95th percentile 98.0% 98.2% 98.3% 98.1% 97.9% 97.6% 96.0% 94.7% 96.5% 96.3% 97.8% 98.1%

75th percentile 95.8% 95.7% 96.6% 96.7% 95.6% 92.9% 85.5% 70.4% 61.3% 78.9% 96.3% 96.6%

mean 94.0% 95.3% 95.9% 95.7% 94.1% 91.6% 86.9% 83.4% 87.0% 88.0% 94.7% 94.9%

50th percentile 89.2% 80.7% 93.1% 94.4% 91.1% 78.9% 57.8% 25.1% 31.6% 28.6% 92.1% 90.1%

25th percentile 64.3% 64.4% 28.6% 89.7% 78.9% 52.5% 29.1% 57.7% 75.0% 62.5% 40.5% 57.8%

10th percentile 34.1% 83.3% 78.9% 72.0% 57.8% 28.6% 65.2% 88.2% 100.0% 100.0% 83.3% 53.6%

5th percentile 53.6% 93.8% 88.2% 57.7% 36.4% 49.1% 83.3% 100.0% 100.0% 100.0% 100.0% 78.1%

3.0

95th percentile 98.0% 98.2% 98.3% 98.1% 97.9% 97.6% 96.0% 94.7% 96.5% 96.3% 97.8% 98.1%

75th percentile 95.8% 95.7% 96.6% 96.7% 95.6% 92.9% 85.5% 70.4% 61.3% 78.9% 96.3% 96.6%

mean 94.2% 95.7% 96.1% 95.7% 94.1% 91.9% 88.2% 86.1% 89.3% 89.7% 94.9% 95.2%

50th percentile 89.2% 80.7% 93.1% 94.4% 91.1% 78.9% 57.8% 48.4% 63.1% 46.2% 92.1% 90.1%

25th percentile 64.3% 100.0% 46.2% 89.7% 78.9% 52.5% 58.3% 100.0% 100.0% 100.0% 40.5% 57.8%

10th percentile 68.2% 100.0% 100.0% 72.0% 57.8% 57.2% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

5th percentile 100.0% 100.0% 100.0% 100.0% 41.1% 98.1% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

4.5

95th percentile 98.0% 98.2% 98.3% 98.1% 97.9% 97.6% 96.0% 94.7% 96.5% 96.3% 97.8% 98.1%

75th percentile 95.8% 95.7% 96.6% 96.7% 95.6% 92.9% 85.5% 70.4% 61.3% 78.9% 96.3% 96.6%

mean 94.4% 95.9% 96.2% 95.7% 94.2% 92.2% 89.3% 88.2% 91.0% 91.2% 95.1% 95.4%

50th percentile 89.2% 80.7% 93.1% 94.4% 91.1% 78.9% 57.8% 72.6% 94.7% 69.2% 92.1% 90.1%

25th percentile 64.3% 100.0% 69.3% 89.7% 78.9% 52.5% 87.4% 100.0% 100.0% 100.0% 57.7% 57.8%

10th percentile 100.0% 100.0% 100.0% 72.0% 57.8% 85.8% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

5th percentile 100.0% 100.0% 100.0% 100.0% 61.6% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
28 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

Table 15. Monthly statistics of Tappan Lake, Ohio, daily mean flow-by amounts for indicated pumping rates and target minimum 

flow-by amounts, expressed as a percentage of corresponding statistic based on observed outflows.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day; color scale is gradient from maximum value, in green, to minimum value, in red]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Daily mean flow-by amounts expressed as a percentage of observed outflow statistics, 

for indicated months and pumping rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 1 Mgal/d

2.0

95th percentile 99.6% 99.6% 99.6% 99.6% 99.6% 99.5% 99.0% 98.2% 98.1% 99.2% 99.6% 99.6%

75th percentile 99.0% 98.9% 99.0% 99.2% 98.8% 97.4% 95.4% 91.5% 90.9% 93.8% 99.3% 99.2%

mean 98.6% 98.7% 98.8% 98.9% 98.6% 97.7% 96.1% 95.2% 95.3% 96.6% 98.9% 98.8%

50th percentile 96.9% 90.9% 97.0% 97.7% 97.3% 94.9% 90.3% 82.7% 74.6% 85.1% 98.4% 97.4%

25th percentile 88.9% 71.4% 72.4% 95.3% 94.8% 90.3% 80.2% 66.7% 83.3% 58.8% 87.2% 87.1%

10th percentile 65.6% 100.0% 95.2% 59.8% 90.3% 78.8% 69.0% 100.0% 100.0% 100.0% 71.4% 57.1%

5th percentile 90.9% 100.0% 100.0% 100.0% 59.3% 64.5% 100.0% 100.0% 100.0% 100.0% 95.2% 87.0%

3.0

95th percentile 99.6% 99.6% 99.6% 99.6% 99.6% 99.5% 99.0% 98.2% 98.1% 99.2% 99.6% 99.6%

75th percentile 99.0% 98.9% 99.0% 99.2% 98.8% 97.4% 95.4% 91.5% 90.9% 93.8% 99.3% 99.2%

mean 98.7% 98.8% 98.9% 98.9% 98.6% 97.8% 96.4% 96.0% 96.3% 97.0% 99.0% 98.9%

50th percentile 96.9% 90.9% 97.0% 97.7% 97.3% 94.9% 90.3% 82.7% 74.6% 85.1% 98.4% 97.4%

25th percentile 88.9% 100.0% 72.4% 95.3% 94.8% 90.3% 80.2% 100.0% 100.0% 100.0% 87.2% 87.1%

10th percentile 88.9% 100.0% 100.0% 100.0% 90.3% 78.8% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

5th percentile 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

6.0

95th percentile 99.6% 99.6% 99.6% 99.6% 99.6% 99.5% 99.0% 98.2% 98.1% 99.2% 99.6% 99.6%

75th percentile 99.0% 98.9% 99.0% 99.2% 98.8% 97.4% 95.4% 91.5% 90.9% 93.8% 99.3% 99.2%

mean 98.7% 98.9% 99.0% 98.9% 98.6% 97.8% 96.7% 96.5% 96.8% 97.3% 99.0% 98.9%

50th percentile 96.9% 90.9% 97.0% 97.7% 97.3% 94.9% 90.3% 82.7% 98.5% 85.1% 98.4% 97.4%

25th percentile 88.9% 100.0% 100.0% 95.3% 94.8% 90.3% 80.2% 100.0% 100.0% 100.0% 87.2% 87.1%

10th percentile 100.0% 100.0% 100.0% 100.0% 90.3% 82.2% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

5th percentile 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

Pumping rate = 2 Mgal/d

2.0

95th percentile 99.3% 99.3% 99.3% 99.3% 99.2% 98.9% 98.0% 96.4% 96.2% 98.4% 99.2% 99.3%

75th percentile 98.0% 97.8% 98.1% 98.3% 97.5% 94.8% 90.9% 83.0% 81.8% 87.6% 98.5% 98.4%

mean 97.3% 97.6% 97.8% 97.8% 97.1% 95.5% 92.4% 91.0% 91.4% 93.5% 97.8% 97.7%

50th percentile 93.8% 81.8% 93.9% 95.4% 94.5% 89.8% 80.7% 65.3% 49.2% 70.1% 96.8% 94.9%

25th percentile 77.9% 71.4% 44.7% 90.6% 89.7% 80.7% 60.3% 66.7% 83.3% 58.8% 74.3% 74.2%

10th percentile 44.4% 100.0% 95.2% 59.8% 80.7% 57.6% 69.0% 100.0% 100.0% 100.0% 71.4% 57.1%

5th percentile 90.9% 100.0% 100.0% 100.0% 52.6% 64.5% 100.0% 100.0% 100.0% 100.0% 95.2% 87.0%

3.0

95th percentile 99.3% 99.3% 99.3% 99.3% 99.2% 98.9% 98.0% 96.4% 96.2% 98.4% 99.2% 99.3%

75th percentile 98.0% 97.8% 98.1% 98.3% 97.5% 94.8% 90.9% 83.0% 81.8% 87.6% 98.5% 98.4%

mean 97.4% 97.7% 97.9% 97.9% 97.2% 95.6% 93.0% 92.4% 93.0% 94.3% 98.0% 97.8%

50th percentile 93.8% 81.8% 93.9% 95.4% 94.5% 89.8% 80.7% 65.3% 65.7% 70.1% 96.8% 94.9%

25th percentile 77.9% 100.0% 71.4% 90.6% 89.7% 80.7% 60.3% 100.0% 100.0% 100.0% 74.3% 74.2%

10th percentile 88.9% 100.0% 100.0% 100.0% 80.7% 57.6% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

5th percentile 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
Limitations 29

Table 15. Monthly statistics of Tappan Lake, Ohio, daily mean flow-by amounts for indicated pumping rates and target minimum 

flow-by amounts, expressed as a percentage of corresponding statistic based on observed outflows.—Continued

[ft3/s, cubic foot per second; Mgal/d, million gallons per day; color scale is gradient from maximum value, in green, to minimum value, in red]

Target 

minimum 

flow-by 

(ft3/s)

Statistic

Daily mean flow-by amounts expressed as a percentage of observed outflow statistics, 

for indicated months and pumping rates

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pumping rate = 2 Mgal/d—Continued

6.0

95th percentile 99.3% 99.3% 99.3% 99.3% 99.2% 98.9% 98.0% 96.4% 96.2% 98.4% 99.2% 99.3%

75th percentile 98.0% 97.8% 98.1% 98.3% 97.5% 94.8% 90.9% 83.0% 81.8% 87.6% 98.5% 98.4%

mean 97.4% 97.8% 97.9% 97.9% 97.2% 95.7% 93.5% 93.3% 93.9% 94.9% 98.0% 97.9%

50th percentile 93.8% 81.8% 93.9% 95.4% 94.5% 89.8% 80.7% 67.2% 98.5% 70.1% 96.8% 94.9%

25th percentile 77.9% 100.0% 100.0% 90.6% 89.7% 80.7% 76.9% 100.0% 100.0% 100.0% 74.3% 74.2%

10th percentile 100.0% 100.0% 100.0% 100.0% 80.7% 82.2% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

5th percentile 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

Pumping rate = 3 Mgal/d

2.0

95th percentile 98.9% 98.9% 98.9% 98.9% 98.8% 98.4% 97.0% 94.7% 94.3% 97.6% 98.8% 98.9%

75th percentile 97.0% 96.7% 97.1% 97.5% 96.3% 92.3% 86.3% 74.5% 72.7% 81.4% 97.8% 97.6%

mean 95.9% 96.4% 96.7% 96.7% 95.7% 93.3% 89.0% 87.3% 88.0% 90.7% 96.8% 96.6%

50th percentile 90.7% 72.7% 90.9% 93.2% 91.8% 84.6% 71.0% 48.0% 32.8% 55.2% 95.3% 92.3%

25th percentile 66.8% 71.4% 35.7% 85.9% 84.5% 71.0% 40.5% 66.7% 83.3% 58.8% 61.5% 61.3%

10th percentile 44.4% 100.0% 95.2% 59.8% 71.0% 36.4% 69.0% 100.0% 100.0% 100.0% 71.4% 57.1%

5th percentile 90.9% 100.0% 100.0% 100.0% 52.6% 64.5% 100.0% 100.0% 100.0% 100.0% 95.2% 87.0%

3.0

95th percentile 98.9% 98.9% 98.9% 98.9% 98.8% 98.4% 97.0% 94.7% 94.3% 97.6% 98.8% 98.9%

75th percentile 97.0% 96.7% 97.1% 97.5% 96.3% 92.3% 86.3% 74.5% 72.7% 81.4% 97.8% 97.6%

mean 96.1% 96.6% 96.9% 96.8% 95.8% 93.4% 89.8% 89.1% 90.0% 91.8% 97.0% 96.8%

50th percentile 90.7% 72.7% 90.9% 93.2% 91.8% 84.6% 71.0% 48.0% 65.7% 55.2% 95.3% 92.3%

25th percentile 66.8% 100.0% 71.4% 85.9% 84.5% 71.0% 51.3% 100.0% 100.0% 100.0% 61.5% 61.3%

10th percentile 88.9% 100.0% 100.0% 100.0% 71.0% 54.8% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

5th percentile 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

6.0

95th percentile 98.9% 98.9% 98.9% 98.9% 98.8% 98.4% 97.0% 94.7% 94.3% 97.6% 98.8% 98.9%

75th percentile 97.0% 96.7% 97.1% 97.5% 96.3% 92.3% 86.3% 74.5% 72.7% 81.4% 97.8% 97.6%

mean 96.2% 96.7% 96.9% 96.8% 95.8% 93.6% 90.6% 90.4% 91.2% 92.7% 97.1% 96.9%

50th percentile 90.7% 72.7% 90.9% 93.2% 91.8% 84.6% 71.0% 67.2% 98.5% 57.9% 95.3% 92.3%

25th percentile 66.8% 100.0% 100.0% 85.9% 84.5% 71.0% 76.9% 100.0% 100.0% 100.0% 61.5% 61.3%

10th percentile 100.0% 100.0% 100.0% 100.0% 71.0% 82.2% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

5th percentile 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
30 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

0 5,000 10,000 15,000 20,000 25,000 30,000

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

1,000,000

1,100,000

1,200,000

1,300,000

1,400,000

1,500,000

Cumulative surplus water, in millions of gallons

Day number

 EXPLANATION

 Atwood Lake

 Leesville Lake

Tappan Lake

Figure 3. Graph showing surplus-water mass curves based on current target minimum outflows for the Atwood, Leesville, and 

Tappan Lakes in the Muskingum River Watershed, Ohio.
Glossary 31

References Cited

LAWriter Ohio Laws and Rules, 2000, Ohio Revised 

Code—Chapter 6101—Conservancy districts, accessed 

February 4, 2013, at http://codes.ohio.gov/orc/6101.

Ohio Department of Natural Resources, 2011, Precipitation in Ohio: Ohio Department of Natural Resources 

Fact Sheet 92–11, 2 p., accessed April 29, 2013, at 

http://www.ohiodnr.com/portals/7/pubs/pdfs/fctsht11.pdf.

SAS Institute, Inc., 2011, Base SAS(R) 9.2 Procedures 

Guide—Statistical Procedures (3d ed.): The UNIVARIATE Procedure—Calculating percentiles, accessed 

May 15, 2010, at http://support.sas.com/documentation/

cdl/en/procstat/63104/HTML/default/viewer.htm#procstat_

univariate_sect028.htm.

U.S. Army Corps of Engineers, 2005, Muskingum Basin 

Infrastructure Study, accessed February 4, 2013, at 

http://www.lrh.usace.army.mil/Portals/38/docs/CORPS_-_

Muskingum_Infrastructure_Report_2005_.pdf.

U.S. Army Corps of Engineers, 2013a, Huntington District–Water Management—Atwood Lake, accessed 

February 4, 2013, at http://www.lrh-wc.usace.army.mil/wc/

atins.htm.

U.S. Army Corps of Engineers, 2013b, Huntington District–Water Management—Leesville Lake, accessed 

February 4, 2013, at http://www.lrh.usace.army.mil/

Missions/Recreation/Ohio/LeesvilleLake.aspx.

U.S. Army Corps of Engineers, 2013c, Huntington District–Water Management—Tappan Lake, accessed 

February 4, 2013, at http://www.lrh.usace.army.mil/

Missions/Recreation/Ohio/TappanLake.aspx.

Glossary

flow-by The computed net flow in the stream immediately 

downstream from a lake or reservoir, after accounting for 

withdrawals. The flow-by amount equals the outflow minus 

any withdrawals. Flow-by amounts are, by definition, available to support water uses downstream from the lake or 

reservoir.

minimum in-stream flow-target multiple A multiplier applied 

to established minimum in-stream flow targets to compute new 

hypothetical target minimum flow-by amounts. 

outflow The total amount of water discharged from a lake or 

reservoir before withdrawals.

seasonal pool levels Target water levels for a lake or reservoir that vary as a function of season. In Ohio, winter pool levels typically are set lower than summer pool levels to facilitate 

greater flood control. 

surplus water The lake or reservoir outflow minus the 

target minimum flow-by amount. Surplus water represents the 

amount of water that potentially is available for withdrawal 

while still meeting the minimum flow-by target immediately 

downstream from the lake or reservoir.

surplus water mass curve A curve produced by plotting 

the cumulative amount of surplus water as a function of time. 

Mass curves can be used to determine whether hypothetical 

water demands can be met at all times or, if not, to determine 

the maximum amount and duration of demand excess.

target minimum flow-by Minimum in-stream flow targets 

downstream from the lake or reservoir, after accounting for 

withdrawals. Target minimum flow-by amounts represent 

goals for minimum in-stream flows; however, they are not 

legal mandates and may not be achievable during extended 

low-flow periods.

withdrawals Water removed for some purpose from a lake, 

reservoir, or their outflows. Withdrawals are not part of the 

flow-by and as such are not available to support in-stream 

water uses downstream from the lake or reservoir.
32 An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio
Appendix 1 33

Appendix 1.

Table 1-1. Cumulative surplus water at the Atwood, Leesville, and Tappan Lakes as a function of target 

minimum flow-by amount.

This table is a separate document, available for downloading at http://pubs.usgs.gov/sir/2013/5112/.


Koltun—An Analysis of Potential Water Availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio—Scientific Investigations Report 2013–5112