U.S. Department of the Interior

U.S. Geological Survey 3

In cooperation with the 

Kentucky Natural Resources and 

Environmental Protection Cabinet

Modeling Hydrodynamics and Water 

Quality in Herrington Lake, Kentucky

Water-Resources Investigations Report 99-4281

science 

USGS

for a changing world
Much appreciation is extended to the following U.S. Geological Survey employees for 

their contributions:

Illustrations by: Aimee C. Downs, Geographer

Editing and layout by: Bonnie Stich Fink, Editorial Assistant

Reviewed by: Dale M. Robertson, Research Hydrologist; W. Reed Green, 

Hydrologist (Biology); Charles G. Crawford, Supervisory Hydrologist (EnvSci); and 

Jerad D. Bales, Hydrologist (Modeling)
U.S. Department of the Interior 

U.S. Geological Survey

Modeling Hydrodynamics and Water 

Quality in Herrington Lake, Kentucky

By Angela S. Grain, Allison A. Shipp, andThomas O. Mesko, U.S. Geological 

Survey, and G. Lynn Jarrett, University of Louisville

Water-Resources Investigations Report 99-4281

In cooperation with the 

Kentucky Natural Resources and 

Environmental Protection Cabinet

Louisville, Kentucky 

2000
U.S. DEPARTMENT OF THE INTERIOR

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

Any use of trade, product, or firm names in this publication is for descriptive purposes only and 

does not imply endorsement by the U.S. Government.

For additional information write to:

District Chief, Kentucky District 

U.S. Geological Survey 

Water Resources Division 

9818 Bluegrass Parkway 

Louisville, KY 40299-1906

Copies of this report can be purchased from:

U.S. Geological Survey 

Branch of Information Services 

Box 25286 

Denver, CO 80225-0286
CONTENTS

Abstract........................................................................................................................................................^ 1

Introduction ................................................................................................................................................................^ 1

Description of study area....................................................................................................................................... 6

Acknowledgments....................................................^ 6

Collection and analysis of data ........................................................................................................................................ 6

Bathymetric data.................................................................................................................................................... 9

Meteorologic data.................................................................................................................................................. 9

Hydrologic data...................................................................................................................................................... 9

Physical water-quality characteristics.................................................................................................................... 9

Chemical and biological water-quality characteristics........................................................................................... 13

Nutrients ....................................................................................................................................................... 13

Chlorophyll a................................................................................................................................................ 13

Phytoplankton............................................................................................................................................... 13

Carlson Trophic State Index .................................................................................................................................. 14

Ambient conditions.......................................................................................................^^ 14

Hydrology .............................................................................................................................................^ 14

Physical characteristics.......................................................................................................................................... 15

Water quality.......................................................................................................................................................... 15

Nitrogen and phosphorus ............................................................................................................................. 19

Chlorophyll a and phytoplankton.................................................................................................................. 19

Estimation of nitrogen and phosphorus loads to Herrington Lake ................................................................................... 27

Simulation of hydrodynamics, constituent transport, and water quality........................................................................... 28

Model description and grid.................................................................................................................................... 28

Boundary and initial conditions............................................................................................................................. 28

Hydraulic boundary conditions..................................................................................................................... 28

Chemical boundary conditions...................................................................................................................... 28

Model parameters and other variables ................................................................................................................... 30

Model fit ................................................................................................................................................................ 30

Hydrology..................................................................................................................................................... 30

Temperature...........................................................^ 32

Dissolved oxygen.......................................................................................................................................... 32

Nitrogen and phosphorus ............................................................................................................................. 32

Chlorophyll a......................................................................................^ 37

Sensitivity analysis................................................................................................................................................. 37

Limitations of CE-QUAL-W2 model for Herrington Lake................................................................................... 39

Phosphorus reductions needed to attain selected trophic state indexes ........................................................................... 39

Partitioning loads ................................................................................................................................................... 40

Reservoir response to phosphorus reductions........................................................................................................ 44

Carlson Trophic State Index for phosphorus.......................................................................................................... 44

Carlson Trophic State Index for chlorophyll a....................................................................................................... 51

Summary and conclusions ................................................................................................................................................ 51

References cited ............................................................................................................................................................... 52

Appendix 1: CE-QUAL-W2 input file for Dix River, January 1, 1996 to December 31, 1996........................................ 57

Appendix 2: Chemical kinetic-rate coefficients and hydraulic and thermal parameters specified as

model input, Herrington Lake, Kentucky, 1996 ................................................................................................. 71

Appendix 3: Discharge and nutrient concentrations for selected tributaries entering Herrington Lake,

Kentucky, October 25, 1995-September 28,1996.............................................................................................. 77

Appendix 4: Average discharge outflows in 1996 at two withdrawal structures at the Dix River Dam........................... 79

Contents III
FIGURES

1-4. Maps showing:

1. Location of study area, Herrington Lake, Kentucky ............................................................................. 2

2. Location of State-permitted Kentucky Pollutant Discharge Elimination System sites,

and location of water-withdrawal or intake sites, Dix River, Kentucky................................................ 4

3. Generalized land use of Dix River Basin, Kentucky ............................................................................. 7

4. Location of Herrington Lake, Kentucky, model segments, reservoir-sampling stations,

and surface-water gaging and stream-inflow sampling stations ........................................................... 8

5. Graph showing precipitation at Dix Dam, Kentucky, 1995-96.................................................................... 10

6. Hydrograph showing daily mean discharge for Clarks Run near Danville, Kentucky,

water years 1995-96...................................................................................................................................... 11

7. Hydrograph showing daily mean discharge for Dix River near Danville, Kentucky,

water years 1995-96...................................................................................................................................... 12

8-14. Graphs showing:

8. Observed vertical profiles of water temperature at three reservoir-sampling stations,

Herrington Lake, Kentucky, April 23, June 18, and September 26, 1996 ............................................ 16

9. Observed vertical profiles of dissolved oxygen at three reservoir-sampling stations,

Herrington Lake, Kentucky, April 23, June 18, and September 26, 1996 ............................................ 17

10. Observed vertical profiles of pH at three reservoir-sampling stations, Herrington Lake,

Kentucky, April 23, June 18, and September 26, 1996 ......................................................................... 18

11. Average monthly nitrate-nitrogen (NO3-N) in Herrington Lake epilimnetic and

hypolimnetic samples for three reservoir-sampling stations, March-October 1996.............................. 21

12. Average monthly total phosphorus and soluble reactive phosphorus in Herrington Lake

epilimnetic and hypolimnetic samples for three reservoir-sampling stations, March-October 1996.... 23

13. Average monthly chlorophyll a concentrations (in micrograms per liter (jig/L)) at five

reservoir-sampling stations in Herrington Lake, Kentucky, April-October 1995-96 ............................ 24

14. Monthly distribution of the relative abundance of major algal forms at three reservoirsampling stations in Herrington Lake, Kentucky, May-October 1995-96............................................. 26

15. Diagram showing two-dimensional grid used to represent Herrington Lake in CE-QUAL-W2.................. 29

16-21. Graphs showing:

16. Observed and simulated water levels at Herrington Lake, Kentucky,

March 28-September 24, 1996............................................................................................................... 31

17. Observed and simulated vertical profiles of water temperature at three reservoir-sampling

stations, Herrington Lake, Kentucky, April 23, June 18, and September 26, 1996............................... 33

18. Observed and simulated vertical profiles of dissolved oxygen at three reservoir-sampling

stations, Herrington Lake, Kentucky, April 23, June 18, and September 26, 1996............................... 34

19. Observed and simulated nitrate-nitrogen in Herrington Lake epilimnetic and hypolimnetic

samples for three reservoir-sampling stations, March-September 1996................................................ 35

20. Observed and simulated soluble reactive phosphorus in Herrington Lake epilimnetic and

hypolimnetic samples for three reservoir-sampling stations, March-September 1996.......................... 36

21. Observed and simulated chlorophyll a in Herrington Lake epilimnetic samples for three

reservoir-sampling stations, March-September 1996............................................................................ 38

22-25. Boxplots showing:

22. Distribution of simulated soluble reactive phosphorus concentrations at Kennedy Bridge (S3), 

Water Tower (S2), and Chenault Bridge (SI) in the Herrington Lake model for input soluble 

reactive phosphorus reductions from all sources for March 1-May 31, June 1-August 15, and 

August 16-September 28, 1996 ............................................................................................................ 47

23. Distribution of simulated soluble reactive phosphorus concentrations at Kennedy Bridge (S3), 

Water Tower (S2), and Chenault Bridge (SI) in the Herrington Lake model for input soluble 

reactive phosphorus reductions from Dix River and Clarks Run for March 1-May 31, 

June 1-August 15, and August 16-September 28, 1996 ...................................................................... 48

IV Contents
24. Distribution of simulated chlorophyll a concentrations at Kennedy Bridge (S3),

Water Tower (S2), and Chenault Bridge (SI) in the Herrington Lake model for input soluble

reactive phosphorus reductions from all sources for March 1-May 31, June 1-August 15,

and August 16-September 28, 1996....................................................................................................... 49

25. Distribution of simulated chlorophyll a concentrations at Kennedy Bridge (S3),

Water Tower (S2), and Chenault Bridge (SI) in the Herrington Lake model for input soluble

reactive phosphorus reductions from Dix River and Clarks Run for March 1-May 31,

June 1-August 15, and August 16-September 28,1996 ....................................................................... 50

TABLES

1. State-permitted discharge limits for specific sites located in the Dix River watershed, Kentucky,

and water-withdrawal or intake sites ................................................................................................................ 5

2. Statistical summary of selected chemical and biological constituents for epilimnetic (surface)

samples collected during 1996 at Herrington Lake, Kentucky ......................................................................... 20

3. Statistical summary of selected chemical constituents for hypolimnetic (near bottom)

samples collected during 1996 at Herrington Lake, Kentucky ......................................................................... 22

4. Dominant algae as a percentage of the total abundance and the percent of sample occurrences,

Herrington Lake, Kentucky, 1995-96 ............................................................................................................... 25

5. Estimated water year 1996 loads of nitrate-nitrogen and soluble reactive phosphorus contributed

to Herrington Lake, Kentucky, by selected tributaries ...................................................................................... 27

6. Daily mean discharge and concentrations of soluble reactive phosphorus input to the Herrington Lake

model for selected tributaries and selected periods in 1996 ............................................................................. 41

7. Average loads of soluble reactive phosphorus input to the Herrington Lake model for selected

tributaries and selected periods in 1996 ............................................................................................................ 42

8. Daily mean discharge and concentration of soluble reactive phosphorus input to the Herrington Lake 

model for Northpoint Training Center, Chimney Rock Resort, and Danville Wastewater-Treatment 

Plant during selected periods in 1996 ............................................................................................................... 42

9. Average loads of soluble reactive phosphorus input to the Herrington Lake model for

Northpoint Training Center, Chimney Rock Resort, and the Danville Wastewater-Treatment Plant

during selected periods in 1996 ........................................................................................................................ 42

10. Average loads of soluble reactive phosphorus and percent total loads for nonpoint and point sources

of Herrington Lake, Kentucky, in 1996 ............................................................................................................ 43

11. Model-predicted average seasonal Carlson Trophic State Index values for soluble reactive 

phosphorus (SRP) computed for simulated alternative reductions in phosphorus inputs to 

Herrington Lake, Kentucky, in 1996.................................................................................................................. 45

12. Model-predicted average annual Carlson Trophic State Index values for soluble reactive 

phosphorus (SRP) computed for simulated alternative reductions in phosphorus inputs to 

Herrington Lake, Kentucky, in 1996.................................................................................................................. 45

13. Model-predicted average seasonal Carlson Trophic State Index values for chlorophyll a computed

for simulated alternative reductions in phosphorus inputs to Herrington Lake, Kentucky, in 1996 ................. 46

14. Model-predicted average annual Carlson Trophic State Index values for chlorophyll a computed

for simulated alternative reductions in phosphorus inputs to Herrington Lake, Kentucky, in 1996 ................. 46

Contents V
CONVERSION FACTORS, VERTICAL DATUM, AND ABBREVIATIONS

Multiply By To obtain

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

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

foot (ft) 0.3048 meter

inch (in.) 2.54 centimeter

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

mile (mi) 1.609 kilometer

milligrams per square foot per day [mg/(ft2/d)] 0.09290 milligrams per square meter per day

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

square mile (mi2) 2.590 square kilometer

ton 907.2 kilogram

ton per year (ton/yr) 907.2 kilogram per year

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

°C = (°F-32)/1.8

Sea level: In this report, "sea level" refers to the National Geodetic Vertical Datum of 1929 

(NGVD of 1929) a geodetic datum derived from a general adjustment of the first-order level 

nets of both the United States and Canada, formerly called Sea Level Datum of 1929.

Concentrations of chemical constituents in water are given either in milligrams per 

liter (mg/L) or micrograms per liter (jig/L).

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius ((iS/cm at 

25°C).

Water year: The 12-month period from October 1 through September 30. The water year is 

designated by the calendar year in which it ends.

VI Contents
Modeling Hydrodynamics and Water Quality in 

Herrington Lake, Kentucky

By Angela S. Grain, Allison A. Shipp, and Thomas O. Mesko, U.S. Geological Survey, and 

G. Lynn Jarrett, University of Louisville

Abstract

Bathymetric, meteorologic, hydrologic, 

water-quality, and biological data collected in 

the Herrington Lake watershed were used to 

construct a laterally averaged, two-dimensional 

model (CE-QUAL-W2) of the reservoir that is 

capable of simulating hydrodynamics, 

temperature, and water-quality parameters. Input 

to the model based on 1996 conditions in the 

watershed and adjustments to kinetic-rate 

coefficients to constituents being simulated 

provided good agreement (root mean square 

error (RMSE) <20 percent) between measured 

and simulated water temperature, dissolved 

oxygen, and nitrate-nitrogen (NO3-N), but only

poor agreement (RMSE >20 percent) for soluble 

reactive phosphorus (SRP), ammonia-nitrogen 

(NH3-N), and chlorophyll a.

The Herrington Lake model was used to 

evaluate the effectiveness of several possible 

management strategies for achieving the Total 

Maximum Daily Loads for phosphorus to 

Herrington Lake. Reductions in concentrations 

of SRP inputs to the reservoir were simulated for 

the Dix River, four tributaries, and two permitted 

wastewater-treatment sites to explore the effects 

of such reductions on the reservoir's water 

quality.

The results of several simulations in which 

SRP concentrations in all inflows were reduced 

from 30 to 80 percent, in 10-percent increments, 

were compared to the Herrington Lake model. 

Additional simulations included those in which 

inflow concentrations of SRP were reduced only

for the Dix River and Clarks Run, the major 

inflows to Herrington Lake.

A comparison of the Carlson Trophic State 

Index (TSI) values calculated from the simulated 

SRP concentrations and simulated chlorophyll a 

concentrations were compared to evaluate the 

effectiveness of possible management strategies 

for the reservoir. Simulation results indicated 

that a 60-percent reduction in SRP 

concentrations from all the inflows would cause 

a decrease in the annual Carlson TSI for 

phosphorus value from 70 to 64; a similar 

decrease in the TSI value would result from a 

60-percent reduction in SRP concentrations in 

only the Dix River and Clarks Run. Reductions 

in SRP concentrations in the inflows did not 

result in decreases in the Carlson TSI for 

chlorophyll a. This is probably a consequence of 

the model being unable to simulate 

concentrations of chlorophyll a as accurately as 

it does the concentrations of SRP. Thus, 

reductions in the Carlson TSI for SRP probably 

represent the effect of management strategies 

more accurately than the Carlson TSI for 

chlorophyll a.

INTRODUCTION

Herrington Lake is a reservoir on the Dix River 

in the Kentucky River Basin (fig. 1). As is true of 

many reservoirs throughout the southeastern United 

States (Kennedy and Walker, 1990), Herrington Lake 

is subject to excessive nutrient loading, which results 

in the deterioration of water-quality conditions, 

problematic algal blooms, and fish kills. The 

reservoir receives pollutants from point and nonpoint

Abstract 1
Outer Bluegrass Inner Bluegrass

Western Kentucky 

Coal Field.

Ohio River 

Alluvium

\

Mississippi 

Embayment

Eastern Kentucky 

Coal Field

Mississippi Plateau 

PHYSIOGRAPHIC REGIONS

Kentucky

River

Basin

Dix 

River 

KENTUCKY Basin

INDEX MAP

38° -

37°30' -

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

Universal Transverse Mercator projection 

Zone 16

Figure 1. Location of study area, Herrington Lake, Kentucky.

2 Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky
sources along its length. The Dix River watershed 

has 24 permitted wastewater-discharge sites 

(David Leist, Kentucky Natural Resources and 

Environmental Protection Cabinet Division of 

Water, written commun., 1998) (fig. 2 and table 1). 

Herrington Lake directly receives wastewater 

discharge from 6 of the 24 wastewater-discharge 

sites.

In response to the 1972 Clean Water Act 

passed by the United States Congress, the 

Commonwealth of Kentucky listed Herrington Lake 

in the 305(b) report to Congress as being one of six 

reservoirs in Kentucky not supporting its designated 

use as a warm-water aquatic habitat (Kentucky 

Natural Resources and Environmental Protection 

Cabinet, 1992a). Epilimnetic concentrations of 

dissolved oxygen (DO) of less than 5 mg/L were 

cited as a principal reason the reservoir did not 

support the intended use designation. This low level 

of DO is the primary contributing factor for reported 

fish kills. Dix River and Clarks Run, two major 

tributaries of the reservoir, were also cited in the 

1998 305(b) report (Kentucky Natural Resources and 

Environmental Protection Cabinet, 1998). These two 

tributaries partially support their designated uses as 

"swimmable" and "fishable." The cited reasons for 

low levels of DO include: agricultural runoff, septictank leakage, urban/suburban storm-water runoff, 

and wastewater-treatment plant (WWTP) discharges.

Starting in 1992, the Commonwealth of 

Kentucky also listed Herrington Lake under section 

303(d) of the Clean Water Act for not attaining 

water-quality standards for phosphorus (Kentucky 

Natural Resources and Environmental Protection 

Cabinet, 1992b). Each state is required to determine 

a Total Maximum Daily Load (TMDL) for water 

bodies listed under section 303 (d). The goals of the 

TMDL program are to address concerns about 

specific pollutant loads to a water body and to ensure 

that the water body complies with water-quality 

standards. A TMDL determines the loading capacity 

of the water body for a single constituent that 

prevents the water body from exceeding waterquality standards. The equation for a TMDL as 

provided by the U.S. Environmental Protection

Agency (USEPA) (U.S. Environmental Protection 

Agency, 1991) follows:

TMDL = Loading capacity = Waste Load Allocation + 

Background + Nonpoint Source + Margin of Safety (1)

The calculation of the TMDL provides a basis 

for the State to develop an implementation plan for a 

specific water body in order to bring it into 

compliance with established standards. The loading 

capacity of a water body can be calculated in a 

number of ways. One way is to examine the 

simulated response of a water body to reductions in 

pollutant loading to determine when compliance with 

water-quality standards will be reached.

An index based on chlorophyll a 

concentrations for use in classifying the trophic state 

of water bodies was adopted by the Commonwealth 

of Kentucky for evaluating the trophic state of lakes 

and reservoirs throughout Kentucky. The Kentucky 

Natural Resources and Environmental Protection 

Cabinet Division of Water (KDOW) evaluated the 

trophic state of Herrington Lake in 1973 and 1983 

(Kentucky Natural Resources and Environmental 

Protection Cabinet, 1984). On the basis of this index, 

the reservoir was classified as eutrophic.

The U.S. Geological Survey (USGS), in 

cooperation with the Kentucky Natural Resources 

and Environmental Protection Cabinet Division of 

Water, investigated the water quality of Herrington 

Lake. Specific objectives of this study were to: 

(1) estimate point source and nonpoint source 

nitrogen and phosphorus loads contributed to the 

reservoir by the selected tributaries and the nitrogen 

and phosphorus loads of the mainstem of the Dix 

River; (2) identify principal sources of phosphorus to 

the reservoir; (3) estimate the retention rate of 

nitrogen and phosphorus and determine the spatial 

and temporal distribution of nutrients, chlorophyll a, 

and phytoplankton communities within the reservoir; 

(4) determine the nutrient-assimilation capacity of 

the reservoir; and (5) evaluate the effect of alternative 

nutrient loading reductions on the water quality of 

Herrington Lake.

INTRODUCTION 3
84'45'

37'45'

37'30'

84'30'

EXPLANATION

Kentucky Pollutant Discharge 

Elimination System site

Withdrawal/intake site

036 KILOMETERS

Base from U.S. Geological Survey, digital data,1:100,000.1983 

Universal Transverse Mercator projection 

Zone 16

Rgure 2. Location of State-permitted Kentucky Pollutant Discharge Elimination System sites, and location of 

water-withdrawal or intake sites, Dix River, Kentucky.

4 Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky
Table 1. State-permitted discharge limits for specific sites located in the Dix River watershed, Kentucky, 

and water-withdrawal or intake sites

[KDOW, Kentucky Division of Water; Mgal/d, million gallons per day; , no station number; MHP, Mobile Home Park; 

DHR, Department for Human Resources]

Map 

number/letter 

(figure 2) Station name

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

A

B

C

CityofBrodhead

City of Crab Orchard

City of Stanford

Baird Oil Company

City of Lancaster

Hustonville Elementary School

Hustonville Apartments

Herrington Haven Subdivision

Whirlpool Corporation

Phillips Lighting

Texaco Bulk Plant

City of Danville

Horse Shoe Bend Subdivision

Private Residence

Greenview MHP

Northpoint Training Center 

(formerly known as Kentucky 

DHR Youth Center)

Paradise Camp Condos

Robinson Elementary School

Chimney Rock Resort

Village Inn Restaurant

Burgin Elementary and High 

Schools

Keystone Brush Company

Private residence

Kentucky Utilities Brown Power

City of Stanford (reservoir 

intake)

City of Lancaster (reservoir 

intake)

Danville Country Club 

(withdrawal)

KDOW 

station Permitted flow 

number (Mgal/d) Receiving stream

Permitted discharge sites

04033006

04033008

04033002

04033001

04032003

04032001

04032012

04032006

04031008

04031007

04031005

04031010

04030000

04030010

04030008

04030006

04030012

04031002

04030005

04030004

04030003

04030002

04030000

04030001

Withdrawal/intake sites

04033004

04032002

0.150

.000

.800

.001

1.000

.006

.003

.008

.000

.300

.000

4.800

.012

.001

.004

.300

.026

.006

.015

.001

.008

.006

.001

.000

.000

.000

.000

Dix River

Dix River

Logan Creek

Logan Creek

White Oak Creek

Hanging Fork Creek

Hanging Fork Creek

Dix River

Clarks Run

Clarks Run

Clarks Run

Clarks Run

Herrington Lake

Herrington Lake

Mocks Branch

Herrington Lake

Herrington Lake

McKecknie Creek

Herrington Lake

Cane Run

Cane Run

Cane Run

Cane Run

Herrington Lake

Neals Creek (Stanford Reservoir)

Unnamed tributary to White Oak 

Creek (Lancaster Reservoir)

Clarks Run

INTRODUCTION 5
This report describes the ambient physical, 

chemical, and biological characteristics of 

Herrington Lake and its major tributaries; the 

procedures used in the construction and sensitivity 

analysis of a numerical model of the reservoir; and 

the simulation of potential management strategies for 

the reservoir. The spatial and temporal distribution of 

chlorophyll a and phytoplankton are described in 

Grain (1998).

Description of Study Area

Herrington Lake is a warm, monomictic 

reservoir in the Inner Bluegrass physiographic region 

of Kentucky and is located in parts of Mercer, 

Garrard, and Boyle Counties (fig. 1). The reservoir 

was formed in the mid-1920's with the completion of 

the Dix Dam, and at the time of construction was the 

highest dam (270 ft) east of the Rocky Mountains. 

The reservoir is maintained and operated by the 

Kentucky Utilities Company for the primary purpose 

of hydropower generation. The two largest towns 

near the reservoir are Danville and Wilmore, Ky. 

Danville has a population of 12,420; Wilmore has a 

population of 4,215 (U.S. Bureau of the Census, 

1991).

fy

Herrington Lake has a surface area of 4.6 mi , 

a volume of 254,000 acre-ft, a length of 35 mi (at full 

pool), and mean and maximum depths of 78 ft and 

250 ft, respectively (U.S. Environmental Protection

Agency, 1977). The Dix River watershed (318 mi2) 

comprises various land-use types, including 

approximately 70-percent agricultural, 25-percent 

forest, and 3-percent urban areas. Land-use data were 

compiled from 1:250,000-scale digital data 

(U.S. Geological Survey, 1986a) (fig. 3). The 

watershed is hilly in the headwaters, leading to 

gently rolling hills at the dam.

Acknowledgments

The authors acknowledge the cooperation, 

information, and assistance provided by Bradley C. 

Young, Kentucky Utilities Company, for furnishing 

discharge, pan evaporation, and precipitation data for 

Herrington Lake, Ky., the National Weather Service 

and the University of Kentucky Spindletop Research 

Farm for meteorological data, and Paul A. 

Bukaveckas, University of Louisville, Louisville, 

Ky., for providing guidance to the senior author 

while she was a graduate student at the University.

COLLECTION AND ANALYSIS 

OF DATA

Bathymetric, meteorologic, hydrologic, 

physical, water-quality, and biological data were 

collected and compiled from a variety of sources for 

this investigation. Water samples for chemical 

analysis were collected from selected tributaries, the 

main stem of the Dix River, and from Herrington 

Lake during 1995 and 1996 by the USGS. Biological 

samples were collected from Herrington Lake during 

1995 and 1996 by the University of Louisville. Five 

inflow stations (Dix River, Clarks Run, Mocks 

Branch, McKecknie Creek, and Cane Run) were 

sampled (fig. 4) over a range of seasonal and 

hydrologic conditions. Five reservoir-sampling 

stations were selected to characterize the upstream 

(riverine), middle (transition), and downstream 

(lacustrine) sections of the reservoir. The reservoirsampling stations included Chenault Bridge [S1 (in 

model segment 5)], the Water Tower [S2 (model 

segment 11)], Kennedy Bridge [S3 (model 

segment 16)], Ashes Creek [S4 (model segment 18)], 

and Dix River Dam [S5 (model segment 19)] (fig. 4). 

Chenault Bridge (SI), Water Tower (S2), Kennedy 

Bridge (S3), and Dix River Dam (S5) were within the 

mainstem of the reservoir; however, Ashes 

Creek (S4) was in an embayment. Detailed sampling 

and analytical methods are described below.

6 Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky
37°30'

37*45'

EXPLANATION

__Land use 

|s|£ | Agricultural 

^B Urban 

^^ Forest 

^B Other

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

Universal Transverse Mercator projection 

Zone 16

0

I 

0 3

3

6

6 MILES

KILOMETERS

Figure 3. Generalized land use of Dix River Basin, Kentucky.

COLLECTION AND ANALYSIS OF DATA 7
84" 45'

37' 45'

37' 37' 30"

84' 37' SO"

I

EXPLANATION

 Reservoir-sampling station with 

downstream-order number 

and model identifier

 Inflow-sampling station with

downstream-order number

 Model-segment separator with 

model-segment identifier

A Surface-water gaging station

with downstream-order number

Island )) Chenault Bridge 

S1) 

8525fJ,

3 

S

Base from U.S. Geological Survey, digital data. 1:100,000.1983 

Universal Transverse Mercator projection 

Zone 16

Figure 4. Location of Herrington Lake, Kentucky, model segments, reservoir-sampling stations, and 

surface-water gaging and stream-inflow sampling stations.

8 Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky
Bathymetric Data

The USGS conducted a bathymetric survey of 

Herrington Lake in September 1994. Seventy 

transects were evaluated using a differential globalpositioning system and a digital-recording acoustic 

fathometer with an analog strip chart backup using 

procedures recommended by the U.S. Army Corps of 

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

1994). The digital data were compared for 

consistency with the analog strip chart and corrected 

as necessary. These data were provided to 

I.E. Edinger Associates, Inc., who prepared the file 

of input data for the reservoir bathymetry required by 

the CE-QUAL-W-2 model (Edward M. Buchak, 

I.E. Edinger and Associates, Inc., written commun., 

1997).

Meteorologic Data

Regional meteorologic data were obtained 

from the National Weather Service (NWS). The 

University of Kentucky Spindletop Research Farm 

(located approximately 75 mi from Herrington Lake) 

provided hourly solar-radiation, air-temperature, 

dew-point, wind-speed, and wind-direction data. 

Hourly cloud-cover data were estimated by using a 

regression model that relates hourly cloud cover to 

hourly solar radiation collected by the NWS at 

Louisville, Kentucky. Precipitation data (fig. 5) and 

pan-evaporation data were collected at the Dix River 

Dam by the Kentucky Utilities Company.

Hydrologic Data

Discharge data were collected at USGS 

streamgaging stations on Clarks Run near Danville, 

Ky., and Dix River near Danville, Ky. (figs. 6 and 7) 

(McClain and others, 1996, 1997). Stream discharge 

was measured at 4- to 8-week intervals from 

February-November 1995 and 

January-September 1996 on selected tributaries of 

Herrington Lake, which include Cane Run, Mocks 

Branch, and McKecknie Creek. Daily mean 

discharge was estimated for these tributaries using 

drainage-area ratios based on the streamflow records 

at the Clarks Run station.

The amount of flow from subsurface-karst 

conduits into the reservoir is unknown, but may be 

significant. Thus, mass balance inputs may be overor under-estimated because the assessment of flow 

from any such conduits was beyond the scope of this 

project. Discharge measured in streams was assumed 

to enter the reservoir with no losses or gains from the 

karst system.

Outflows and water-level data for the Dix 

River Dam were provided by Kentucky Utilities 

Power Company (Bradley C. Young, Kentucky 

Utilities Power Company, written commun., 1997). 

Data for several short periods during which 

measuring equipment malfunctioned were estimated.

Physical Water-Quality 

Characteristics

Water temperature and specific conductance 

were measured at 2- to 8-week intervals at the five 

selected inflows to Herrington Lake during 

February-November 1995 and 

January-September 1996, using a YSI Model S-C-T 

thermistor. For the five reservoir-sampling stations, 

water temperature, DO, pH, and specific conductance 

were measured at 1-ft depth intervals (surface to 

bottom) using a YSI 6000 water-quality meter. 

Light-attenuation profiles were measured using a 

Protomatic photometer equipped with upward and 

downward spherical sensors. Light profile readings 

were taken at 1.5-ft intervals from the surface to the 

lower boundary of the photic zone (1 percent of 

subsurface irradiance) to estimate coefficients of 

light attenuation. The attenuation coefficient (Kd) 

was calculated from the slope of the natural 

logarithm of down-welling irradiance against depth 

(Kirk, 1983).

COLLECTION AND ANALYSIS OF DATA 9
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COLLECTION AND ANALYSIS OF DATA 11
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Chemical and Biological 

Water-Quality Characteristics

Water samples were collected at 1- to 4-week 

intervals at five reservoir stations during 

March-October 1995 and 1996. In addition, a total of 

22 water samples were collected at five inflow 

stations from February-November 1995 and 

January-September 1996. The samples were 

analyzed for chlorophyll a, total phosphorus (TP), 

soluble reactive phosphorus (SRP), nitrate-nitrogen 

(NO3-N), and ammonia-nitrogen (NH^N). Samples

for chlorophyll a and light-attenuation profile data 

were not collected at the tributaries.

Nutrients

Samples were collected at depths of 2, 15, and 

30 ft below the reservoir surface and 10 ft above the 

bottom at the reservoir-sampling stations using a 

2.5-liter Kemmerer water sampler. Grab samples 

were collected from the Dix River, Clarks Run, 

Mocks Branch, Cane Run, and McKecknie Creek. 

Samples for analysis of nutrients were sent to the 

Kentucky State University laboratory. NH^N and 

NO3-N concentrations were measured using an 

Orion 920A pH/ISE (ion-selective electrode) meter 

(American Public Health Association, 1992). SRP 

concentrations were analyzed on unfiltered samples 

using the manual ascorbic acid method (American 

Public Health Association, 1992). TP concentrations 

were analyzed by the digestion method followed by 

the manual ascorbic acid method (American Public 

Health Association, 1992).

Gelman A/E glass fiber filters. The samples were 

analyzed for chlorophyll a at the University of 

Louisville Water Resources Laboratory. Grain (1998) 

provides a detailed description of the analytical 

procedure for determination of chlorophyll a 

concentrations.

Chlorophyll a concentrations, in micrograms 

per liter, were converted to milligrams per liter of 

algal biomass for the Herrington Lake model by use 

of two conversion factors. The first factor converts 

chlorophyll a to carbon. Literature values for the first 

factor range from 10 to 112 for total phytoplankton 

and from 14 to 67 for blue-green algae (Bowie and 

others, 1985). An average value of 19 was used based 

on measurements made from Herrington Lake 

phytoplankton samples. The second factor converts 

carbon to biomass. A value of 0.47 was taken from 

the literature for the second factor (Bowie and others, 

1985).

Phytoplankton

Phytoplankton samples were collected at each 

reservoir station from three depths corresponding to 

those sampled for chlorophyll a analyses. 

Phytoplankton samples were processed using 

standard procedures (American Public Health 

Association, 1992). Phytoplankton taxa 

identifications were determined from Prescott 

(1978), Whitford and Schumacher (1984), Smith 

(1950), Desikachary (1959), and Dillard (1989). 

Enumeration of phytoplankton species followed 

standard procedures (American Public Health 

Association, 1992). A detailed description of 

phytoplankton identification and enumeration is 

provided by Grain (1998).

Chlorophyll a

Samples for analysis of chlorophyll a were 

collected at three equally spaced depths between the 

surface and the 1-percent light level at the reservoir 

sampling stations using a 2.5-liter Kemmerer water 

sampler. Samples were stored on ice in 1-liter 

polyethylene bottles and processed within 1 to 

2 hours of collection by filtration through 0.45 urn

COLLECTION AND ANALYSIS OF DATA 13
Carlson Trophic State Index where

Chlorophyll a concentrations can be used to 

determine a trophic state index (TSI) (Carlson, 

1977). The Carlson TSI equation for chlorophyll a is:

TSI(chla) = 10 6-

where

In2 (2)

chla is chlorophyll a concentrations in 

micrograms per liter, and

In(chla) is the natural logarithm of chlorophyll a 

concentrations in micrograms per liter.

Carlson also developed an equation for 

calculating a TSI using TP. The Carlson TSI equation 

for TP is:

TSI(TP) = 10

In

6-

In2 (3)

where

TP is the total phosphorus concentration in 

micrograms per liter, and

In 48 

TP is the natural logarithm of a constant 

divided by the total phosphorus 

concentration in micrograms per liter.

Trophic-state classifications based on the Carlson TSI 

are oligotrophic (0-20), mesotrophic (31-50), 

eutrophic (51-69), and hypereutrophic (>69) 

(Carlson, 1977) for both the chlorophyll a and 

TP indexes.

KDOW uses a modified Carlson TSI in which 

log base 10 is used rather than the natural log to 

calculate the TSI values for the state's reservoirs. The 

modified Carlson TSI equations used were:

chla is chlorophyll a concentrations in 

micrograms per liter, and

chla is the log base 10 of chlorophyll a

concentrations in micrograms per liter; 

and

TSI (TP) = 4.2 + 33.2 (loglO TP), (5)

where

TP is the total phosphorus concentration in 

micrograms per liter, and

log]0 TP is the log base 10 of the total 

phosphorus concentration in 

micrograms per liter.

Depth-composited samples collected by the 

KDOW from the euphotic zone at three sampling 

sites in Herrington Lake at the KDOW sampling sites 

from March 1 through September 30 at 

approximately 2-month intervals in 1973 and 1983 

were analyzed for chlorophyll a and total 

phosphorus. A seasonal TSI value was calculated for 

each site and season, then averaged to determine a 

single TSI value for the reservoir for that year. Using 

the modified Carlson TSI, KDOW computed a TSI 

chlorophyll a value of 52 for 1973, and 56 for 1983 

(Kentucky Natural Resources and Environmental 

Protection Cabinet, 1984).

AMBIENT CONDITIONS

Hydrology

TSI(chla) = 30.6 + 22.6 (loglO chla),

Long-term average annual precipitation for the 

Dix River watershed ranges from 48 to 52 in. 

(U.S. Geological Survey, 1986b). Average annual 

(4) runoff ranges from 18 to 20 in. The summer of 1995 

was dryer than the summer of 1996 (fig. 5). The total 

cumulative rainfall for June-August 1995 was 12 in. 

During the same period in 1996, the total cumulative 

rainfall was about 15 in. The greatest total monthly 

cumulative rainfall occurred in May 1995.

14 Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky
The flow of Dix River and Clarks Run (figs. 6 

and 7) were compared with the precipitation patterns. 

Clarks Run and Dix River contribute approximately 

94 percent of the total surface flow to the reservoir. 

Mean annual discharge for Dix River in 1995 and

1996 was 442 and 591 ft3/s, respectively. These 

results were compared to the historical data record 

(56 years) for Dix River and showed 1995 to be

ranked 33rd out of the 56 annual values and 1996 to

be ranked 11 th . No-flow conditions were observed in 

McKecknie Creek once in February and once in

April of 1996. Flow of less than 1 ft3/s was measured 

at least once during 1995 at the other tributaries, 

primarily in late summer. The selected minor 

tributaries of Herrington Lake had a combined

average flow of about 40 ft3/s.

Physical Characteristics

Water temperature in the reservoir varied both 

spatially and seasonally (fig. 8). Temperature 

distributions indicate that, as the inflow reached the 

transitional zone of the reservoir, the cooler water 

sank below the epilimnion. In April, temperature 

differences at Chenault Bridge (SI), between the 

surface and bottom, did not exceed 9°F indicating 

water-column mixing; in June, however, the 

epilimnetic and hypolimnetic temperatures differed 

by more than 14°F (fig. 8). In contrast, temperature 

differences at Kennedy Bridge (S3) were never less 

than 17°F and were as much as 37°F. Temperature 

distributions from mid-reservoir to the dam were 

similar throughout 1995-96.

The water in Herrington Lake began to stratify 

in early April 1996 and remained stratified 

throughout the summer. Thermal stratification 

gradually weakened, and the reservoir underwent 

complete thermal mixing by mid-October 1996. 

During stratification, epilimnion and hypolimnion 

temperatures differed more than 30°F.

Water Quality

Marked seasonal and spatial patterns in 

concentrations of DO were evident in 1996 (fig. 9).

Concentrations of DO less than 5 mg/L were typical 

at Chenault Bridge (SI) in 1996. A metalimneticoxygen minimum was measured in June 1996. A 

metalimnetic-oxygen minimum is produced by 

oxidizable material sinking into the metalimnion. 

Also contributing to the metalimnetic-oxygen 

minimum is the transport of allocthonous material 

and the decomposition of the material in the 

metalimnetic region. The potential origins of the 

oxidizable material are deposition from the overlying 

productive epilimnion and from watershed runoff 

entering the metalimnetic region. The denser water in 

the metalimnion reduces the sinking rate of the 

oxidizable material and allows more time for 

decomposition, thereby depleting oxygen levels in 

the metalimnion (Wetzel, 1983). Concentrations of 

DO near 0 mg/L were measured in the hypolimnion 

at Water Tower (S2) and Kennedy Bridge (S3) 

several times in 1996 (fig. 9). These low 

concentrations could be the result of increased 

demands from the hypolimnetic waters and bed 

sediments.

As a result of phytoplankton production, 

values of pH were elevated near the surface of 

Herrington Lake (fig. 10). The lower values of pH 

measured in the hypolimnion may be caused by the 

respiration and decomposition processes. Vertical 

differences in pH were associated with reservoir 

stratification. After thermal turnover in late October, 

the pH values remained uniform in the reservoir.

Specific conductance values in the upper 

reservoir were controlled by inflow from the Dix 

River and Clarks Run. Specific conductance in other 

parts of the reservoir was affected by in-reservoir 

processes such as stratification, algal productivity, 

and decomposition of organic material. Specificconductance values were elevated in April and 

October, but were low in June. The elevated specificconductance values were associated with minimal 

precipitation and little runoff. During stratification, a 

horizontal plume of high specific conductivity 

extended from Chenault Bridge (SI) to Kennedy 

Bridge (S3), indicating that this layer of water did 

not mix with adjacent water layers.

AMBIENT CONDITIONS 15
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TEMPERATURE, IN DEGREES FAHRENHEIT

KENNEDY BRIDGE (S3) WATER TOWER (S2) 

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Figure 8. Observed vertical profiles of water temperature at three reservoir-sampling stations, Herrington Lake, Kentuck

September 26,1996.
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KENNEDY BRIDGE (S3)

DISSOLVED-OXYGEN CONCENTRATION, IN MILLIGRAMS PER LITER

WATER TOWER (S2) 

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Figure 9. Observed vertical profiles of dissolved oxygen at three reservoir-sampling stations, Herrington Lake, Kentuc

September 26,1996.
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September 26,1996.
Nitrogen and Phosphorus

Mean concentrations of nitrogen in the 

epilimnion show little spatial variability, but show 

substantial seasonal variability in 1996 (table 2). 

Concentrations of NO3-N were an order of 

magnitude higher in March than in September. 

Epilimnetic NH^N concentrations ranged from 

<10 to 290 |ig/L at all stations (table 2, fig. 11). 

However, the majority of NH4-N concentrations 

were below the laboratory reporting level of 10 |ig/L. 

The increased NH^-N concentrations coincided with 

periods of low DO. Only small increased variations 

in NH^N were observed in June and August 1996.

Epilimnion and hypolimnion concentrations of 

phosphorus were more variable than concentrations 

of nitrogen in Herrington Lake (tables 2 and 3, 

figs. 11 and 12). There were no pronounced spatial 

patterns in the concentrations of phosphorus in the 

epilimnion (table 2, fig. 12). In general, 

concentrations of phosphorus tended to be higher in 

the mid to late summer than in the spring.

Elevated concentrations of phosphorus were 

associated with periods of heavy rainfall. The 

variation in concentrations of phosphorus in the 

tributaries associated with runoff were greater than 

the variation in concentrations of nitrogen. Similar 

spatial and seasonal patterns in the concentrations of 

NO3-N were measured in the hypolimnion.

Chlorophyll a and Phytoplankton

Monthly average concentrations of 

chlorophyll a ranged from 2 to 35 |ig/L and exhibited 

similar seasonal and spatial patterns in 1995 and 

1996 (fig. 13). At the mid-reservoir station Kennedy 

Bridge (S3) and at the Dix River Dam (S5), the 

highest concentrations of chlorophyll a generally 

occurred in April. The decrease in May may be 

associated with spring runoff. Higher concentrations 

of chlorophyll a during the summer could be related 

to the decreased turbidity and adequate 

concentrations of nitrogen and phosphorus. Low 

concentrations of chlorophyll a in late summer could 

be associated with lower concentrations of NO3 -N. 

Previous studies have shown at certain times 

Herrington Lake is nitrogen limited

(U.S. Environmental Protection Agency, 1977). In 

contrast to what was measured at the other reservoir 

stations, the highest concentration of chlorophyll a at 

Chenault Bridge (SI) were observed in late summer. 

The reason that Chenault Bridge (SI) shows the 

opposite pattern as downstream stations is unknown.

A total of 135 species of phytoplankton were 

found in Herrington Lake (Grain, 1998). The most 

abundant phytoplankton in Herrington Lake were 

blue-green algae (Cyanophyta) (table 4). During 

1995 and 1996, the most abundant blue-green genera 

were Aphanocapsa and Oscillatoria. Both genera 

represented a combined relative abundance of more 

than 40 percent. The most widely distributed bluegreen algae was the genera Dactylococcopsis. The 

genera Stephanodiscus represented the most 

abundant diatom (Bacillariophyta). The Chlorophyta 

was the most widely distributed taxa in the reservoir 

(table 4).

The 1995 and 1996 phytoplankton community 

included Cyanophytes, Chlorophytes, and 

Bacillariophytes at each sampling location in the 

reservoir (fig. 14). Distinct seasonal patterns in 

phytoplankton composition were evident in both 

sampling years. Bacillariophyte counts were 

extremely low in the summer, after spring peaks. 

Cyanophytes were abundant throughout the summer, 

particularly the coccoid-shaped, colonial forms.

Spatial variability in phytoplankton 

community composition was evident in both years. 

In 1995, the abundance of Chlorophytes was greater 

downstream [Kennedy Bridge (S3) and at the Dix 

River Dam (S5)] than at the upstream sampling 

station [Chenault Bridge (SI)]. The reverse was true, 

however, for Chlorophyte abundance in 1996. 

Chenault Bridge (SI) exhibited greater 

Bacillariphyte abundance than Kennedy Bridge (S3) 

or the Dix River Dam (S5) in 1995 and 1996. 

Cyanophytes were abundant throughout the three 

seasons at all three stations, particularly the coccoidshaped, colonial forms.

AMBIENT CONDITIONS 19
Table 2. Statistical summary of selected chemical and biological constituents for epilimnetic (surface) samples collected durin

(Spring, April to May; Summer, June to August; Fall, September to October; n, sample size; Min, minimum; Max, maximum; ug/L, micrograms per liter; N, 

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Constituent

Nitrate-nitrogen dissolved (jAg/L as N)

Ammonia-nitrogen dissolved (jAg/L as N)

Total phosphorus (jAg/L as P)

Soluble reactive phosphorus (LAg/L as P)

Chlorophyll a (photic-zone composite; JAg/L)

Nitrate-nitrogen dissolved (Lig/L as N)

Ammonia-nitrogen dissolved (LAg/L as N)

Total phosphorus (LAg/L as P)

Soluble reactive phosphorus (Lig/L as P25

Chlorophyll a (photic-zone composite; LAg/L)

Nitrate-nitrogen dissolved (Lig/L as N)

Ammonia-nitrogen dissolved (LAg/L as N)

Total phosphorus (ng/L as P)

Soluble reactive phosphorus (LAg/L as P)

Chlorophyll a (photic-zone composite; Lig/L)

n Min

10 930

10 <10

8 110

8 40

21 <1

15 1,240

15 <10

12 80

15 10

18 4

15 1,370

15 <10

15 70

15 20

18 <1

Spring

Max

2,520

100

310

160

18

3,040

<10

720

210

33

2,800

<10

530

360

35

Mean n

Chenault Bridge (SI)

1,900 14

20 14

200 14

70 14

7 33

Water tower (S2)

2,110 15

<10 15

240 15

90 15

15 24

Dam (S5)

2,130 16

<10 16

220 16

90 16

11 20

Min

100

<10

80

20

2

120

<10

100

50

2

350

<10

50

30

7

Summer

Max

3,030

180

1,180

300

27

3,800

290

1,320

240

30

4,070

240

850

390

35

Mean

1,700

10

390

100

12

1,430

<10

260

140

14

1,450

40

250

90

14
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Figure 11. Average monthly nitrate-nitrogen (NO3-N) in Herrington Lake epilimnetic and hypolimnetic samples for three re

March-October 1996.
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Table 3. Statistical summary of selected chemical constituents for hypolimnetic (near bottom) samples collected during 1996 

[Spring, April to May; Summer, June to August; Fall, September to October; n, sample size; Min, minimum; Max, maximum; ug/L, micrograms per liter; N

<, less than; P, phosphorus]

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Constituent n Min Max

Nitrate-nitrogen dissolved (ng/L as N)

Ammonia-nitrogen dissolved (Hg/L as N)

Total phosphorus (ng/L as P)

Soluble reactive phosphorus (ng/L as P)

Nitrate-nitrogen dissolved (ng/L as N) 10 1,700 3,000

Ammonia-nitrogen dissolved (ng/L as N) 10 <10 <10

Total phosphorus (ng/L as P) 8 100 1,000

Soluble reactive phosphorus (ng/L as P) 10 50 700

Nitrate-nitrogen dissolved (Ug/L as N) 10 1,800 2,900

Ammonia-nitrogen dissolved (ng/L as N) 10 <10 <10

Total phosphorus (ng/L as P) 8 90 520

Soluble reactive phosphorus (ng/L as P) 10 20 190

Summer

Mean n Min

Chenault Bridge (SI)

3 1,540

3 <10

3 180

3 100

Water Tower (S2)

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300 10 200

150 10 100

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100 10 40

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20

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130
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Mar Apr May Jun Jul Aug Sep Oct Mar Apr May Jun Jul Aug Sep Oct Mar Apr 

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- * - AVERAGE SOLUBLE

REACTIVE PHOSPHORUS

w

Figure 12. Average monthly total phosphorus and soluble reactive phosphorus in Herrington Lake epilimnetic and hypolim

sampling stations, March-October 1996.
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Concentration, in |ig/L

Concentration, in |ig/L
Table 4. Dominant algae as a percentage of the total abundance and the percent of sample occurrences, 

Herrington Lake, Kentucky, 1995-96

[ , unidentifiable]

Group Genus Species Variety

Relative 

abundance

Percentage 

of 

samples

Maximum 

relative 

abundance

Most abundant taxa

Cyanophyta

Cyanophyta

Cyanophyta

Cyanophyta

Cyanophyta

Cyanophyta

Cyanophyta

Cyanophyta

Cyanophyta

Chlorophyta

Cyanophyta

Cyanophyta

Cyanophyta

Cyanophyta

Bacillariophyta

Aphanocapsa

Oscillitoria

...

Gomphosphaerium

Aphanothece

...

Aphanocapsa

Oscillitoria

Merismopdeia

Pandorina

Synechoccous

Oscillitoria

Chroococcus

Aphanocapsa

Stephanodiscus

delicatissima

(planctonica)

species 2

lacustris

nidulans

species 3

species

(angustissima)

tennuissima

morum

elongatus

species 1

minimus

elachista

hantzschii

delicatissima

(planctonica)

species 2

compacta

nidulans

species 3

species

(angustissima)

tennuissima

morum

elongatus

species 1

minimus

elachista

tenuis

0.189

.106

.095

.080

.055

.054

.047

.033

.032

.027

.023

.022

.013

.013

.012

0.48

.59

.09

.37

.41

.09

.07

.52

.37

.35

.26

.15

.33

.28

.24

0.757

.790

.564

.814

.692

.302

.918

.333

.223

.616

.409

.081

.282

.115

.221

Most widely distributed taxa

Chlorophyta

Chlorophyta

Chlorophyta

Cyanophyta

Ankistrodesmus

Tetraedron

Ankistrodesmus

Dactylococcopsiis

convolutus

minimus

falcatus

irregularis

convolutus

minimum

falcatus

irregularis

.004

.002

.001

.005

.63

.63

.63

.59

.072

.042

.011

.129

AMBIENT CONDITIONS 25
1995 1996

DIX RIVER DAM (S5) DIX RIVER DAM (S5)

KENNEDY BRIDGE (S3) KENNEDY BRIDGE (S3)

JUN JUL AUG SEP 

CHENAULT BRIDGE (SI)

OCT MAY JUN JUL AUG SEP

CHENAULT BRIDGE (SI)

OCX

EXPLANATION 

| BACILLARIOPHYTES 

] CHLOROPHYTES 

| FILAMENTOUS CYANOPHYTES 

1 COLONIAL CYANOPHYTES

Figure 14. Monthly distribution of the relative abundance of major algal forms at three reservoir sampling 

stations in Herrington Lake, Kentucky, May - October 1995-96.

Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky
ESTIMATION OF NITROGEN AND 

PHOSPHORUS LOADS TO 

HERRINGTON LAKE

Daily NO3 -N and SRP loads and 

concentrations from the tributaries were estimated 

using the FLUX program (Walker, 1987). These 

estimates did not include air-shed input, groundwater input, or consider sediment as potential sources 

of NO3-N and SRP loads.

Daily mean discharge and instantaneous 

concentrations of NO3 -N and SRP from each of the 

inflow tributaries were input into the FLUX program. 

The estimated mean daily discharge was used for 

Cane Run, Mocks Branch, and McKecknie Creek. 

One of three methods (International Joint 

Commission, regression-1, or regression-2) available 

in FLUX was used to estimate the load for each 

constituent at each station. The International Joint 

Commission method applies a flow-weighted mean 

concentration to the mean flow with a bias 

adjustment factor for situations where concentration 

varies with flow. The regression-1 method regresses 

the logarithm of concentration against the logarithm 

of mean daily discharge. The regression-2 method is 

similar except that it corrects for bias that can occur

when regression slopes are high. For each method, 

the data can be stratified seasonally and by discharge 

(for example, a method can be applied separately to 

flows greater than or less than the average discharge) 

and the results of the individual strata aggregated to 

obtain the load. The method with the lowest 

estimated coefficient of variation was used to obtain 

estimates of mean daily NO3 -N and SRP loads and 

concentrations.

Annual loads of NO3 -N and SRP were 

estimated for five Herrington Lake tributaries by 

summing the daily loads estimated by using the 

FLUX program (table 5). The loads of NO3 -N and 

SRP from the Dix River accounted for 70 percent 

and 78 percent, respectively, of the total loads of 

those nutrients entering Herrington Lake. The second 

largest contributor of nutrient loads is Clarks Run, 

accounting for 18 percent of NO3 -N and 14 percent 

of SRP of the total loads of those nutrients entering 

the reservoir. In general, most nonpoint-source 

loading of water bodies occurs during periods of 

elevated flow, which results from surface runoff 

during storm events; nonpoint-source contributions 

are less during low-flow periods. Consequently 

during low-flow periods, point sources contribute 

more nutrient load, relative to the nonpoint source 

nutrient load (FTN Associates Limited, 1998).

Table 5. Estimated water year 1996 loads of nitrate-nitrogen and soluble reactive phosphorus contributed to 

Herrington Lake, Kentucky, by selected tributaries

[reg. 1, regression method 1; reg. 2, regression method 2; S, stratified flows; IJC, International Joint Commission]

Station

Cane Run

Clarks Run

Dix River

McKecknie

Creek

Mocks

Branch

Drainage

area

(square

miles)

3.2

26.4

318

2.55

16.3

FLUX 

method

used for

estimating

nitratenitrogen

loads1

reg. 1

reg. 2, S

IJC

IJC, S

reg. 2, S

Nitrate

load

as

nitrogen

(tons

per year)

22

215

824

13

109

Coefficient

of

variation

(in percent)

9

5

9

15

14

FLUX 

method 

used for

estimating

soluble

reactive

phosphorus

loads1

reg. 1

reg. 2, S

reg. 1

reg. 1

reg. 1

Soluble

reactive

phosphorus

load

(tons

per year)

2

21

117

1

10

Coefficient

of

variation

(in percent)

17

11

52

31

21

'Walker, 1987.

ESTIMATION OF NITROGEN AND PHOSPHORUS LOADS TO HERRINGTON LAKE 27
SIMULATION OF 

HYDRODYNAMICS, 

CONSTITUENT TRANSPORT, 

AND WATER QUALITY

The CE-QUAL-W2 model was used to 

simulate physical and water-quality conditions for 

Herrington Lake for the period January through 

September 1996. CE-QUAL-W2 is an unsteadystate, two-dimensional, laterally averaged 

hydrodynamic and water-quality model (Cole and 

Buchak, 1995). The structure of the model allows the 

simulation of up to 21 water-quality constituents, as 

well as water temperature, water density, and 

hydrodynamic properties. The model was used to 

simulate constituent transport during stratified and 

unstratified conditions, wind and temperature effects, 

and effects of nutrients on DO and phytoplankton 

production.

Model Description and Grid

The reservoir was divided into 20 longitudinal 

segments (figs. 4 and 15) based on bathymetric data 

collected for this study. Each segment was chosen to 

represent and identify potential hydraulic and (or) 

chemical/biological changes throughout the 

reservoir; each individual layer in a segment is a cell. 

All cells within a model segment have the same 

thickness (6.6 ft) and length, but the length of a cell 

varies by segment. Segment lengths range from a 

minimum of 2,960 ft in segments 8, 9, and 14 to a 

maximum of 15,420 ft in segment 6. Stream 

segments 1 and 20 are the upstream and downstream 

boundaries. Within each cell, conditions are 

considered to be homogeneous.

Hydraulic Boundary Conditions

Daily inflow values for the Dix River were 

computed from the streamgage record at the station. 

The reservoir bottom was assumed to be an 

impermeable boundary with no subsurface-karst 

conduits discharging water into the reservoir within 

the model. Bottom heat exchange was assumed to be 

constant in space and time. Boundary conditions at 

the water surface include wind energy and surface 

heat exchange. The shoreline of the reservoir was 

designated as a no-flow boundary. During model 

simulation, the position of the shoreline changes 

because of the fluctuation in the reservoir water level. 

Outflow values from the dam were provided for two 

different gate elevations. Both gate releases were 

included as boundary conditions. The hydraulic 

boundary condition includes water temperature. 

Initial temperatures were assumed to be uniform at 

the start of the model simulation.

Additional hydraulic boundary conditions 

included selected permitted point-source inputs and 

tributaries. The selected permitted point-source 

inputs included Northpoint Training Center, formerly 

known as Kentucky DHR Youth Center in 

segment 10 and Chimney Rock Resort in 

segment 18. The largest permitted discharge directly 

into Herrington Lake was from the Northpoint 

Training Center (0.3 Mgal/d) (table 1). Clarks Run, 

Mocks Branch, McKecknie Creek, and Cane Run 

were the selected tributary inflow stations. Smaller 

tributaries into Herrington Lake (Clear Creek, Boone 

Creek, and Spears Creek) were not included in the 

model. The City of Danville's WWTP discharges 

into Clarks Run (4.8 Mgal/d) and, in turn, flows into 

Herrington Lake. The sampling station on Clarks 

Run is below the outfall of the City of Danville's 

WWTP and, therefore, includes the flow from the 

facility.

Boundary and Initial Conditions Chemical Boundary Conditions

The boundaries of the Herrington Lake model 

include the upstream boundary at the inflow of Dix 

River, the bottom of the reservoir, the water surface, 

the shoreline, the downstream boundary at Dix Dam, 

and the tributaries. Hydraulic and chemical boundary 

conditions are required by the CE-QUAL-W2 model.

28 Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky

Time series for constituents to be simulated in 

the CE-QUAL-W2 model are required at all inflow 

boundaries. The chemical boundary conditions 

included in the Herrington Lake model are 

suspended sediment, total dissolved solids, dissolved 

organic matter, algae, particulate organic matter 

(detritus), PO4 (orthophosphorus), NH4-N, NO3 -N,
MODEL SEGMENT NUMBERS, RESERVOIR-SAMPLING STATION LOCATIONS, AND SELECTED FEATURE LOCATIONS (see figure 4)

oo nz o33 

OOy*

o oI

m(/) o 

o

33 i

oIm

33o

20 19 14 13

0.93

1.43

1.62

1.06

2.80 1.18

0.56

2.67 0.56 1.18

0.93 0.56 1.93 0.56 2.92

MODEL SEGMENT WIDTH, IN MILES

EXPLANATION

BOUNDARY CELL (6.6 feet in height) 

GP ACTIVE CELL (6.6 feet in height) O INACTIVE CELL

DIX DAM

S1 SAMPLING STATION

1.30 1.24

2.24

Figure 15. Two-dimensional grid used to represent Herrington Lake in CE-QUAL-W2.
DO, total inorganic carbon, alkalinity, and iron. The 

Dix River and selected tributary input values for PO4 

and NO3-N were available from the data collected for 

this study. Values of SRP collected for this study 

were used to approximate PO4 . In most situations 

encountered, these two forms of phosphorus are 

virtually equivalent (Chapra, 1997). Daily 

concentrations of NO3-N and SRP for the Dix River 

and the tributaries were estimated with the FLUX 

program as previously described in this report. Time 

series for the other constituents were not available, 

and therefore, were estimated. Data were generated 

to exhibit typical seasonal patterns and relations to 

discharge. The estimated values were compared to 

available data from streams in nearby watersheds to 

determine if the estimated values were realistic. 

These estimated values were within the range of 

available data collected in nearby watersheds. The 

same estimated data were used for the Dix River and 

each of the selected tributary inputs; an example 

input data set (the Dix River) is given in Appendix 1. 

Monthly values of NO3-N, SRP, and NH4-N were 

available for the Northpoint Training Center and 

Chimney Rock Resort point-source discharges; 

values for other constituents were not available and 

also were estimated. Point-source time-series data 

were input only monthly. The model assumed that 

inputs from these discharges were constant during 

any given month.

Model Fit

Water-quality data collected from January to 

September 1996 were used to assess the "fit" of the 

CE-QUAL-W2 model to Herrington Lake. Data for 

evaluation of the model performance optimally 

would be collected weekly or even more frequently. 

For the Herrington Lake model, however, only data 

were collected at 2- to 8-week intervals. These waterquality data are presented in Appendix 3.

The root mean square error (RMSE) was used 

as a measure of model fit. The RMSE statistic is a 

measure of the differences between the observed and 

simulated;

(6)

where

yi observed value,

yi simulated value, and

n the number of paired values.

An RMSE of <20 percent was achieved for 

concentrations of temperature, DO, and NO3-N. The 

RMSE for SRP, NH4-N, and algae was greater than 

20 percent.

Model Parameters and Other 

Variables

Most chemical kinetic-rate coefficients 

required by the CE-QUAL-W2 model are difficult to 

measure directly. Consequently, these coefficients for 

the Herrington Lake simulation were selected from 

values published in the literature (Appendix 2). Some 

coefficients were adjusted within the range shown 

within the literature to improve the model fit. The 

coefficients used do not vary spatially or seasonally. 

The values used are given in Appendix 2, which also 

includes the model code variable, the parameter, and 

the computational purpose of the parameter.

30 Modeling Hydrodynamics and Water Quality in Herrington

Hydrology

Observed and simulated water levels are 

shown in figure 16. Generally, the RMSE between 

measured and simulated water levels was less than 

20 percent. Overall, the water balance between the 

inflow and outflow was approximately 2.4 percent 

after adjustments for withdrawals and pan 

evaporation. The error can be attributed to seepage 

under and around the dam, which has an estimated

range of 9.9 to 20 ft3/s. Daily outflow data at two 

withdrawal structures for the Dix River Dam are 

provided in Appendix 4. The estimated hydraulic 

residence time in Herrington Lake for 1996 was 

344 days.

Lake, Kentucky
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SIMULATION OF HYDRODYNAMICS, CONSTITUENT TRANSPORT, AND WATER QUALITY 31
Temperature

Observed and simulated data are shown for 

selected dates in 1996 for three sampling stations in 

the reservoir (fig. 17). Differences between the 

observed and simulated temperatures were greatest 

near the reservoir bottom, where observed 

temperatures tended to decrease faster than did the 

model-simulated temperatures. In April, a reasonably 

good fit between the observed and simulated 

temperature distributions was indicated at Water 

Tower (S2) and Kennedy Bridge (S3). However, at 

Chenault Bridge (SI), the simulated temperatures at 

deeper depths were cooler than the observed 

temperatures. In June, the model underestimates the 

temperature at deeper depths at the two downstream 

stations and overestimates the temperature at 

Chenault Bridge (SI). In September, the simulated 

temperatures are typically warmer than the observed 

temperatures at all stations and depths. Overall, the 

model tended to better simulate temperature 

distributions during the spring and fall and at stations 

closer to the Dix River Dam (S5).

Dissolved Oxygen

Observed and simulated DO concentrations are 

shown for selected dates in 1996 (fig. 18). In April, 

the model underestimated DO concentrations at 

Kennedy Bridge (S3) and Water Tower (S2). In June, 

at Chenault Bridge (SI), the model simulation 

showed good agreement with the observed DO data; 

however, observed and simulated DO concentrations 

were in poor agreement at Water Tower (S2) and 

Kennedy Bridge (S3). Generally, the poor agreement 

occurred at mid-depths and at deeper depths. The 

model did a poor job of reproducing the 

metalimnetic-oxygen minimum observed at Water 

Tower (S2) and Kennedy Bridge (S3) sampling 

stations. This phenomena was overpredicted at Water 

Tower (S2) and underpredicted at Kennedy 

Bridge (S3). Poor agreement between the observed 

and simulated DO concentrations at mid-depths also 

occurred at Water Tower (S2) in September. The

model also failed to predict the low DO 

concentrations observed at Chenault Bridge (SI) in 

September. The model did predict the near anoxic 

conditions in the hypolimnion at Water Tower (S2) 

and Kennedy Bridge (S3) sampling stations.

Nitrogen and Phosphorus

Generally, simulated epilimnetic and 

hypolimnetic NO3-N concentrations showed good 

agreement with the observed NO3-N (fig. 19). Model 

simulated epilimnetic values of NO3-N at the 

downstream stations were not as good as the 

upstream station, especially from August through 

September 1996, although none of the simulated 

values during this period were particularly good. 

Simulated hypolimnetic values of NO3-N were in 

good agreement at reservoir-sampling stations from 

March through June 1996, and not as good from July 

to September.

The model underestimated the concentrations 

of epilimnetic SRP in June at the Dix River 

Dam (S5) (fig. 20). By early July, however, 

epilimnetic concentrations of SRP were in good 

agreement at that station. Simulated epilimnetic 

concentrations of SRP at the upstream station were in 

good agreement from March through September 

1996. Simulated hypolimnetic concentrations of SRP 

were also in good agreement at the three reservoirsampling stations from March through September 

1996.

Nutrient-mass balances computed for 

Herrington Lake indicate a SRP retention rate of 

approximately 67 percent and a nitrogen retention 

rate of 31 percent. On the basis of the results of the 

CE-QUAL-W2 model simulations, most of the SRP 

settles out in the upper-half (13 mi) of the reservoir.

32 Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky
to

2

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cc

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m

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KENNEDY BRIDGE (S3) 

40 45 50 55 60 65 70 75 80 85 90

TEMPERATURE, IN DEGREES FAHRENHEIT

WATER TOWER (S2) 

40 45 50 55 60 65 70 75 80 85 90 40 45 50 

0

50

100

150

200

EXPLANATION

e OBSERVED 

 SIMULATED

Figure 17. Observed and simulated vertical profiles of water temperature at three reservoir-sampling stations, Herrin

June 18, and September 26,1996.
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DISSOLVED-OXYGEN CONCENTRATION, IN MILLIGRAMS PER LITER

KENNEDY BRIDGE (S3) WATER TOWER (S2) C

0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 

0

50

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ffi 150 

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-i O-iEXPLANATION

o OBSERVED 

 SIMULATED

Figure 18. Observed and simulated vertical profiles of dissolved oxygen at three reservoir-sampling stations, Herrington 

June 18, and September 26,1996.
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SIMULATION OF HYDRODYNAMICS, CONSTITUENT TRANSPORT, AND WATER QUALITY 35
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EXPLANATION

o OBSERVED 

 SIMULATED

Figure 20. Observed and simulated soluble reactive phosphorus in Herrington Lake epilimnetic and hypolimnetic samples f

stations, March-September 1996.
Chlorophyll a

CE-QUAL-W2 does not simulate 

chlorophyll a directly; rather, the model simulates 

algal biomass. Algal biomass was converted to 

chlorophyll a using the conversion factors discussed 

in the section on chlorophyll a under chemical and 

biological water-quality characteristics. Observed 

and simulated chlorophyll a data are shown for 

selected dates in 1996 for three sampling stations in 

the reservoir (fig. 21). During the spring at the 

upstream stations, simulated chlorophyll a 

concentrations were in good agreement. Beginning in 

June, however, the model overestimates 

concentrations of chlorophyll a at those stations. 

Concentrations of chlorophyll a at the dam were 

overestimated by the model from March through 

September 1996. Overall, there was poor agreement 

between the observed and simulated chlorophyll a 

concentrations.

Simulating chlorophyll a concentrations is 

very difficult for many reasons. Phytoplankton are 

not uniformly distributed throughout the reservoir, 

thus, obtaining a representative sample can be 

difficult. Additionally, the CE-QUAL-W2 model 

simulates phytoplankton as a single assemblage, so 

that no distinctions are made between the different 

species of phytoplankton present. As was previously 

discussed in the section on chlorophyll a and 

phytoplankton, there was considerable seasonal and 

spatial variability in phytoplankton. An average 

factor was used to convert algal biomass simulated 

by CE-QUAL-W2 to chlorophyll a for this study; in 

actuality, however, the factor varies with the type of 

phytoplankton and the season. This unknown 

variability can potentially introduce a considerable 

amount of error into the estimation of the 

concentrations of chlorophyll a.

Sensitivity Analysis

A sensitivity analysis of a model allows one to 

evaluate the response of the model to variations in 

input values. If a change in an input value or model

parameter causes significant changes in output values 

(i.e., constituent concentrations), the model is said to 

be sensitive to that input. In practice, a sensitivity 

analysis is conducted by changing (increasing or 

decreasing) the magnitude of a specified input value 

or parameter within reasonable limits while keeping 

all other parameters unchanged. All input values and 

model parameters used in the Herrington Lake model 

were not evaluated because of the large number of 

inputs and parameters. Simulations to evaluate model 

sensitivity were done for each of the model 

parameter changes described below. The model 

output for each of these simulations was compared to 

the original model output.

Algal growth rate (AG), saturation light 

intensity (ASAT), algal mortality rate (AM), algal 

settling rate (AS), and the algal-half saturation 

constant for phosphorus (AHSP) were varied by

^0 percent of the original value to determine the 

sensitivity of the concentrations of chlorophyll a to 

these parameters. Model simulations of chlorophyll a 

concentrations were sensitive to AG, but were less 

sensitive to ASAT and AHSP. Increasing AG resulted 

in increases in chlorophyll a concentrations 

throughout the epilimnion, especially during the 

summer. The model was not sensitive to changes in 

AM and AS. The wind-sheltering coefficient (WSC) 

and the oxygen stoichiometric equivalent for algal

growth (O2AG) were varied by ^O percent of the 

original value to determine the sensitivity of the 

concentrations of DO to these parameters. Vertical 

dissolved-oxygen concentrations were not sensitive 

to the wind-sheltering coefficient (WSC), which 

directly affects reaeration. Model simulations of 

DO concentrations were most sensitive to AG and 

O2AG. Simulated temperatures were not sensitive to 

changes in the light extinction coefficient (EXH2O), 

the adsorption of solar radiation coefficient (BETA), 

or WSC.

SIMULATION OF HYDRODYNAMICS, CONSTITUENT TRANSPORT, AND WATER QUALITY 37
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38 Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky
Limitations of CE-QUAL-W2 Model 

for Herrington Lake

It is important to note that models are not 

reality, but are simply an approximation of what the 

individual modeler believes is reality. Because 

natural systems are complex, modelers must take into 

account the assumptions and limitations of the model 

and have the ability to understand the interactions 

taking place in the system. Some of the model 

limitations include the model representation for 

various chemical and physical processes and the 

quality of the data input into the model.

The scope and cost considerations of the study 

prevented data being collected at optimal intervals 

(weekly) for the model or all needed data being 

measured. This limitation was addressed by using the 

FLUX program to estimate selected constituent 

concentrations and loads between the 4- to 8-week 

sampling intervals and estimating other data from 

available data in other watersheds. The large amount 

of estimated data used for this study affect the 

model's predictive capabilities. Collection of 

additional data at a more frequent sampling interval 

would enable refinement of the model, and, 

consequently, should result in better model 

predictions. In addition, because of several problems 

apparent in the nutrient data, the quality of the 

nutrient analyses for this study were poor. Results of 

a blind sample program for NO3-N indicated 

unacceptable results for the two samples analyzed as 

part of the program. Results of the blind samples for 

SRP were satisfactory; however, it was not 

uncommon for concentrations of SRP to exceed 

those of TP in 1995. Results in 1996 were better.

The CE-QUAL-W2 model water-quality 

algorithms include several important processes that 

control phytoplankton production and nutrient 

cycling; however, these algorithms contain many 

generalizations and assumptions. For example, only a 

single compartment is available to represent all 

phytoplankton species. All phytoplankton species are 

combined and simulated with one set of growth and 

mortality parameters and one carbon to chlorophyll a 

ratio. Most of the kinetic-rate coefficients and 

phytoplankton growth parameters used in the model 

are assumed to be constant. Variations in the

simulation of phytoplankton growth, such as 

phytoplankton growth in response to seasonal 

changes in light or fluctuations in nutrient 

concentrations are not incorporated into the 

Herrington Lake model, which makes it difficult to 

model the seasonal growth of phytoplankton.

The Herrington Lake model does not simulate 

algal biomass, and, consequently, chlorophyll a 

concentrations very well. The model consistently 

overestimates the amount of algal biomass present in 

the reservoir. This is a major limitation of the model. 

The poor simulation of algal biomass could be the 

result of the poor quality of the nutrient data being 

input to the model, or the result of so much of the 

daily input being estimated, or the limitations in 

model algorithms previously described.

The model does not rigorously simulate 

sediment oxygen demand. As a result, DO 

concentrations in the reservoir after turnover may be 

overestimated. This is because the model does not 

account for DO depletion resulting from oxidation 

and reduction reactions.

According to Cole and Buchak (1995), in some 

situations no amount of model parameter adjustment 

will result in an adequately calibrated model; they 

conclude, however, such a model can still be useful. 

Despite the limitations of this version of the 

Herrington Lake model, it is able to simulate the 

general characteristics and dynamics of water quality 

in the reservoir. Consequently, the model can be used 

to show how different management options can affect 

water quality.

PHOSPHORUS REDUCTIONS 

NEEDED TO ATTAIN SELECTED 

TROPHIC STATE INDEXES

The Herrington Lake model was used to 

evaluate the effectiveness of several potential 

management strategies for achieving the TMDL of 

phosphorus for the reservoir. These strategies 

included various reductions in the concentration of 

SRP inputs to the reservoir from the Dix River, four 

tributaries, and two point sources included in the 

model. KDOW defined the period June 1-August 15

PHOSPHORUS REDUCTIONS NEEDED TO ATTAIN SELECTED TROPHIC STATE INDEXES 39
to be critical since this is when concentrations of DO 

of less than 5 mg/L are most likely to occur; when 

DO drops below 5 mg/L, fish kills can occur. The 

effects of SRP reduction on this critical period were 

emphasized in the simulations. Results of the 

simulations for the periods immediately prior to and 

following the critical period also were evaluated. The 

results of the simulation of the potential management 

strategies are presented in this section.

Partitioning Loads

Daily mean discharge and concentrations of 

SRP for the Dix River and four tributaries included in 

the model are shown in table 6 for selected periods. 

Multiplying the average concentration times the 

average discharge for a period does not yield the 

average load of a constituent for that period unless 

the concentration is constant. If concentrations tend 

to increase with streamflow, an average load 

computed in this fashion will underestimate the true 

load. If concentrations tend to decrease with 

streamflow, an average load computed in this fashion 

will overestimate the true load. For this study, daily 

loads were computed with the FLUX program. The 

daily loads for the period of interest were then 

averaged to obtain the load for a period (table 7).

A TMDL (for a specified constituent) is 

calculated from the equation provided by the 

USEPA, equation 1. This equation requires that a 

determination be made of the sources and relative 

contribution of the sources of the contaminant. There 

is one primary point source of nutrients near 

Herrington Lake, the Danville WWTP on Clarks 

Run. Records for the point-source-discharge 

contributions were available from reporting and 

permitting data provided by KDOW. Average 

concentrations of SRP and discharge for the Danville 

WWTP and the two point sources discharging 

directly to Herrington Lake are presented in table 8. 

For the TMDL calculation, the point-source loads for 

a period of interest were calculated by averaging the 

individual loads computed for that period from the 

reported concentrations of phosphorus measured in 

the effluent and the discharge measurements for 

Northpoint Training Center, Chimney Rock Resort,

40 Modeling Hydrodynamics and Water Quality in Herrington

and Danville WWTP. SRP loads from the Danville 

WWTP ranged from 0.3 to 2 tons per period of 

interest (table 9).

During low-flow conditions, Clarks Run 

contributes one-third of the total surface flow and 

about one-third of the total SRP load to the reservoir. 

The sampling station on Clarks Run was below the 

Danville WWTP; therefore, the Clarks Run load 

includes that from both the Danville WWTP load and 

the nonpoint-source contributed load upstream from 

the plant. Two additional minor point sources into the 

reservoir included in the load determinations are the 

Northpoint Training Center and the Chimney Rock 

Resort. Both of these sources discharge directly into 

the reservoir.

For the purpose of the TMDL calculation, the 

total SRP loads obtained from the FLUX program 

included total nonpoint-source loads, plus known 

point-source loads, plus estimated background loads. 

Background loads were estimated with data from a 

watershed of similar size with little or no 

anthropogenic effects. Tributary nonpoint-source 

loads can be estimated by subtracting the estimated 

background load and any point-source load from the 

total SRP load. For example, the load estimate at 

Clarks Run include contributions from the Danville 

WWTP, nonpoint sources, and background sources. 

To estimate the nonpoint-source contribution, the 

Danville WWTP load and the background load were 

subtracted from the load calculated by the FLUX 

program for Clarks Run. Total nonpoint-source loads 

are defined to be the sum of nonpoint-source loads 

and background loads.

Dix River, the major inflow to Herrington 

Lake, is affected by nonpoint sources of nutrients but 

also has point sources located along its length 

(fig. 2). However, the sampling location in the Dix 

River is below all of the point sources. The upstream 

point sources were not considered individually in the 

determination of point-source loads. No attempt was 

made to separate the point- and nonpoint-source 

contributions upstream of the sampling point in the 

Dix River. In determining the other point-source and 

nonpoint-source contributions to Herrington Lake, 

the Dix River is treated as a separate case and both 

types of load contributions are considered together.

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PHOSPHORUS REDUCTIONS NEEDED TO ATTAIN SELECTED TROPHIC STATE INDEXES 41
Table 7. Average loads of soluble reactive phosphorus input to the Herrington Lake model for selected tributaries 

and selected periods in 1996

[Daily loads from the FLUX program were averaged to obtain the loads of soluble reactive phosphorus]

Tons per period

January

March 1

June 1 -

August

Period

1 - February 29

-May 31

August 15

16 -September 28

Dix 

River

17

13

24

7

Clarks 

Run

4

4

2

2

Mocks 

Branch

2

2

2

.7

McKecknie 

Creek

0.2

.2

.1

.1

Cane 

Run

0.5

.5

.2

.2

Background

0.01

.01

.01

.02

Table 8. Daily mean discharge and concentration of soluble reactive phosphorus input to the Herrington Lake 

model for Northpoint Training Center, Chimney Rock Resort, and Danville Wastewater-Treatment Plant during 

selected periods in 1996

[ft3/s, cubic foot per second; SRP, soluble reactive phosphorus; u.g/L, micrograms per liter; WWTP, wastewater-treatment plant; *, 1995-97 

data; soluble reactive phosphorus concentrations were obtained by multiplying the measured total phosphorus concentrations by 0.7]

January

March 1

June 1 -

August

Period

1 - February 29

.-May 31

August 15

16 -September 28

Northpoint 

Training 

Center 

discharge 

(ft3/s)

0.3

.3

.3

.3

Northpoint 

Training 

Center 

SRP 

(H9/L)

15

20

10

15

Chimney 

Rock 

Resort 

discharge 

(tf/s)

0.004

.004

.004

.004

Chimney 

Rock 

Resort 

SRP

(ng/D

150

200

100

150

Danville 

WWTP 

discharge* 

(tf/s)

4.0

7.6

4.9

1.9

Danville 

WWTP 

SRP*

(ng/D

469

1,050

1,190

2,060

Table 9. Average loads of soluble reactive phosphorus input to the Herrington Lake model for Northpoint Training 

Center, Chimney Rock Resort, and the Danville Wastewater-Treatment Plant during selected periods in 1996

January

March 1

June 1 -

Period

1 - February 29

-May 31

August 15

August 16 - September 28

Northpoint 

Training 

Center

0.001

.0006

.0005

.0007

Tons per period

Chimney 

Rock 

Resort

0.0001

.0002

.0001

.0001

Danville 

WastewaterTreatment 

Plant

0.3

2

1

.5

42 Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky
Current background phosphorus 

concentrations would ideally be determined by 

sampling a pristine watershed in an environmental 

setting similar to that of Herrington Lake. No pristine 

watersheds exist in the area surrounding Herrington 

Lake. An alternative is to sample a watershed with 

minimal human disturbance; such a watershed can be 

described as least affected. As a part of the Kentucky 

Watershed Management Plan (Kentucky Natural 

Resources and Environmental Cabinet, 1997), the 

Commonwealth of Kentucky assessed referencereach site data. The results of the reference-reach 

assessment provided an indication of the possible 

background nutrient load to Herrington Lake for the 

period simulated by the CE-QUAL-W2 model. 

Background SRP loads for the Herrington Lake 

Basin were estimated using available data from a 

representative least-affected watershed, that of 

Crooked Creek in the adjacent Salt River Basin. In an 

intensive study conducted from 1991 through 1993, 

the background TP concentration for Crooked Creek 

was determined to be 0.11 mg/L (FTN Associates 

Limited, 1998). For this study, a background SRP

concentration of 0.077 mg/L was obtained by 

multiplying the background TP concentration from 

Crooked Creek by 0.70 because this factor typically 

represents that portion of TP that is SRP. The 

background loading from each inflow was obtained 

by summing the product of the background 

concentration times the daily discharge for each 

tributary times a unit conversion factor. The 

background load for each tributary and the Dix River 

were summed to compute the total background load 

for the reservoir.

Estimated point source, nonpoint source, and 

background loads for Herrington Lake are given in 

table 10. Loads from Dix River are listed separately 

in table 10. The largest contributor of phosphorus to 

Herrington Lake is the Dix River. Background loads 

were estimated to be less than 1 percent of the load 

into Herrington Lake. Estimated point source loads 

(excluding those on Dix River) ranged from 1 to 

9 percent.

Table 10. Average loads of soluble reactive phosphorus and percent total loads for nonpoint and point sources of 

Herrington Lake, Kentucky, in 1996

[<, less than; Dix River, total inflow into Herrington Lake including input from point and nonpoint sources; Total nonpoint sources, sum of soluble 

reactive phosphorus loads from Clarks Run, Mocks, McKecknie, Cane Run, and background; Nonpoint sources, sum of soluble reactive phosphorus 

loads from Clarks Run, Mocks, McKecknie, and Cane Run; Point sources, sum of soluble phosphorus loads from Danville Wastewater-Treatment Plant, 

Chimney Rock Resort, and Northpoint Training Center; Background, based on average phosphorus measurements in Crooked Creek located in Salt 

River Basin (least disturbed)]

Period

Loads of soluble reactive phosphorus, 

in tons per period

Total

Point Dix Nonpoint nonpoint 

sources River sources Background sources

Total toads, 

in percent

Point Dix Nonpoint 

sources River sources Background

January 1 -

February 29

March 1 - May 3 1

June 1 - August 15

August 16 -

September 28

0.3 17

2 13

1 24

.5 7

6

6

3

3

0.01

.01

.01

.002

6

6

3

3

1

9

3

5

73

62

86

67

26 <1

29 <1

11 <1

28 <1

PHOSPHORUS REDUCTIONS NEEDED TO ATTAIN SELECTED TROPHIC STATE INDEXES 43
Reservoir Response to 

Phosphorus Reductions

The effects of phosphorus reductions in the 

reservoir were determined by changes in the Carlson 

TSI values for chlorophyll a and SRP. The KDOW 

calculated a Carlson TSI for chlorophyll a for 

Herrington Lake of 56 in 1983. Simulated 

concentrations of chlorophyll a and SRP obtained 

from the model for 1996 were used to calculate an 

average reservoir TSI for chlorophyll a of 77 and a 

TSI for phosphorus of 70.

Simulations were also run in which the SRP 

concentrations were reduced for only the Dix River 

and Clarks Run. For these simulations, 

concentrations of SRP in the Dix River and Clarks 

Run were reduced simultaneously while all other 

input concentrations were unchanged. The Carlson 

TSI was computed for three locations along the main 

stem of the reservoir: Chenault Bridge (SI), Water 

Tower (S2), and Kennedy Bridge (S3) (fig. 4). In a 

series of simulations, the input concentrations of SRP 

were reduced by a specified percentage from 30 to 

80 percent, in increments of 10 percent. The effects 

on the reservoir of simulated reductions in SRP input 

concentrations were determined by comparing TSI 

values calculated from the concentrations of SRP and 

chlorophyll a simulated by the model and the 

concentrations simulated in the phosphorusreduction model runs. The Carlson TSI values in 

tables 11-14 were not calculated from the single 

average concentration for the period of interest, 

rather individual Carlson TSI's were calculated and 

then averaged to obtain a Carlson TSI value for each 

period of interest. Therefore, a Carlson TSI value 

calculated from a seasonal mean concentration 

estimated from figures 22-25 will not result in the 

same Carlson TSI value as listed in tables 11-14.

Carlson Trophic State Index for 

Phosphorus

Average simulated concentrations of SRP in 

Herrington Lake are reduced as a result of reductions 

in all SRP inputs (fig. 22). The greatest reductions

are indicated for Chenault Bridge (SI) during the 

August 16-September 28 period. Chenault Bridge 

(SI) is the station closest to the Dix River and Clarks 

Run. Since these two inflows are the largest 

contributors of phosphorus to the reservoir, it is 

expected that the largest immediate reduction of 

phosphorus would be observed at Chenault 

Bridge (SI). Reductions are also indicated at stations 

further downstream although the magnitude of the 

predicted reduction is less. The Carlson TSI for SRP 

resulting from the simulated alternative reductions in 

SRP inputs from all sources is given in tables 11 and 

12. There are reductions in the Carlson TSI for SRP 

reflecting the decreased SRP concentrations 

predicted to occur in the Herrington Lake as a result 

of decreased inputs.

The magnitude of the reduction in simulated 

concentrations of SRP in Herrington Lake when only 

the SRP inputs for the Dix River and Clarks Run are 

reduced is similar to that obtained when SRP from all 

of the inputs is reduced (fig. 23). This is not 

surprising since most of the SRP entering Herrington 

Lake is from these two sources. The spatial and 

seasonal patterns of simulated SRP concentrations 

corresponding to reductions in SRP in only the Dix 

River and Clarks Run are nearly identical to those 

obtained from reductions in SRP from all sources. 

SRP reductions in only the Dix River and Clarks Run 

result in Carlson TSI for SRP values that differ little 

from those obtained when the reductions were 

applied to all inflows.

The Carlson TSI for SRP computed for all of 

the management strategies considered in this study 

would still result in Herrington Lake being 

considered eutrophic. Reductions of SRP inputs of 

30 percent or more, however, would result in a 

classification of eutrophic rather than 

hypereutrophic. The largest reductions in the Carlson 

TSI for SRP were predicted to occur at Chenault 

Bridge (SI).

44 Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky
to 

m

o

3D 

O

X 

O

35

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z

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X 

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Table 11 . Model-predicted average seasonal Carlson Trophic State Index values for soluble reactive phosphorus (SRP) co

reductions in phosphorus inputs to Herrington Lake, Kentucky, in 1996

[SRP, soluble reactive phosphorus; %, percent]

March 1 - May 31

Reduction in SRP input, in percent

PHOSPHORUS REDUCTIONS NEEDEDTO A'

Reservoir 

segment 

(figure 4)

Chenault Bridge (SI) 

Water Tower (S2) 

Kennedy Bridge (S3)

Chenault Bridge (SI) 

Water Tower (S2) 

Kennedy Bridge (S3)

Base 30%

65 62 

68 68 

68 68

65 62 

68 68 

68 68

40% 50%

62 61 

68 67 

68 68

62 61 

68 67 

68 68

60% 70%

60 59 

67 67 

68 68

60 59 

67 67 

68 67

80%

June 1 -August 15

Reduction in SRP input, in percent

Base 30% 40% 50% 60% 70% 80%

SRP reductions in all sources

57 67 63 62 60 58 

67 70 68 67 66 66 

68 70 68 68 67 66 

SRP reductions in only Dix River and Clarks Run

57 67 63 62 60 58 

67 70 68 68 67 66 

68 70 68 68 67 67

55 52 

64 63 

66 65

56 53 

65 64 

66 65

Base 

74 

74 

76 

74 

74 

76 

Table 12. Model-predicted average annual Carlson Trophic State Index values for soluble reactive phosp

computed for simulated alternative reductions in phosphorus inputs to Herrington Lake, Kentucky, in 1996

b, percent; SRP, soluble reactive phosphorus]

Annual

Reservoir 

segment 

(figure 4)

Chenault Bridge (SI)

Water Tower (S2)

Kennedy Bridge (S3)

Base

69

71

71

30%

65

69

70

40%

SRP reductions in all sources

63

68

69

50%

61

67

68

60%

59

66

68

SRP reductions in only Dix River and Clarks Run

Chenault Bridge (SI)

Water Tower (S2)

Kennedy Bridge (S3)

69

71

71

65

69

70

63

68

69

61

68

68

59

67

68
Table 13. Model-predicted average seasonal Carlson Trophic State Index values for chlorophyll a computed for simulated a

inputs to Herrington Lake, Kentucky, in 1996

[SRP, soluble reactive phosphorus; %, percent]

ling Hydrodynamics

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Lake, Kentucky

March 1 - May 31

Reduction in SRP input, in percent

Reservoir 

segment 

(figure 4) Base 30% 40% 50% 60%

Chenault Bridge (SI) 57 57 57 57 57

Water Tower (S2) 69 69 69 69 69 

Kennedy Bridge (S3) 76 76 75 75 75

Chenault Bridge (SI) 57 57 57 57 57 

Water Tower (S2) 69 69 69 69 69

Kennedy Bridge (S3) 76 76 75 75 75

70% 80%

57 57

June 1 -August 15 

Reduction in SRP input, in percent 

Base 30% 40% 50% 60%

SRP reductions in all sources

75 74 74 73 73

69 69 80 79 78 78 78 

75 75 82 81 81 80 80 

SRP reductions in only Dix River and Clarks Run

57 57 

69 69

75 75

75 74 74 73 73 

80 79 78 78 78

82 81 81 80 80

70% 80% Base 

72 72 94 

77 77 84 

80 80 80 

72 72 94 

78 77 84 

80 80 80 

Table 14. Model-predicted average annual Carlson Trophic State Index values for chlorophyll a co

for simulated alternative reductions in phosphorus inputs to Herrington Lake, Kentucky, in 1996

[%, percent; SRP, soluble reactive phosphorus]

Reservoir

segment 

(figure 4)

Chenault Bridge (SI)

Water Tower (S2)

Kennedy Bridge (S3)

Base

75

78

79

Annual

30% 40% 50%

SRP reductions in all sources

74 74 74

77 77 76

79 78 78

60% 70% 

73 73 

76 76 

78 78 

SRP reductions in only Dix River and Clarks Run

Chenault Bridge (SI)

Water Tower (S2)

Kennedy Bridge (S3)

75

78

79

75 74 74

77 77 77

79 78 78

74 73 

76 76 

78 78 f 
KENNEDY BRIDGE (S3) WATER TOWER (S2) CHENAULT BRIDGE (S1)

DC 

LU

0. 

CO

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O

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I 0.10

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CC

0.05

0.0 

0.20

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O

0.0

1 1 1 1 I

6 i 4,

1 1 1 1 1 1 1 I 1 1 1 1 1 1 1

0 30 40 50 60 0 30 40 50 60 0 30 40 50 60

PERCENT REDUCTION OF SOLUBLE REACTIVE PHOSPHORUS

EXPLANATION

i

 EXTREME OUTLIER

 OUTLIER

 95th PERCENTILE

 75th PERCENTILE

MEDIAN VALUE

T_ 25th PERCENTILE 

10th PERCENTILE

Figure 22. Distribution of simulated soluble reactive phosphorus concentrations at Kennedy Bridge (S3), 

Water Tower (S2), and Chenault Bridge (S1) in the Herrington Lake model for input soluble reactive 

phosphorus reductions from all sources for March 1-May 31, June 1-August 15, and 

August 16-September28, 1996.

PHOSPHORUS REDUCTIONS NEEDED TO ATTAIN SELECTED TROPHIC STATE INDEXES 47
KENNEDY BRIDGE (S3) WATER TOWER (S2) CHENAULT BRIDGE (S1)

CC 

HI

CC 

HI 

CL

CO 

CC

i 

z

o

o

o 

o

0.20

CO

> 0.15

I 0.10 

0.05

0.0 

0.20

till!

* * * *

1 1 I 1 1

o-10

0.05

0.0 

0.20

CD 0.15

0.10

CO 0.05

D

0.0

1 I 1 i 1

e

1 1 1 1 1

0 30 40 50 60 0 30 40 50 60 0 30 40 50 60

PERCENT REDUCTION OF SOLUBLE REACTIVE PHOSPHORUS

EXPLANATION

o EXTREME OUTLIER 

* OUTLIER

 95th PERCENTILE T 75th PERCENTILE

 MEDIAN VALUE

 25th PERCENTILE 

_L 10th PERCENTILE

Figure 23. Distribution of simulated soluble reactive phosphorus concentrations at Kennedy Bridge (S3), 

Water Tower (S2), and Chenault Bridge (S1) in the Herrington Lake model for input soluble reactive 

phosphorus reductions from Dix River and Clarks Run for March 1-May 31, June 1-August 15, 

and August 16-September 28,1996.

48 Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky
KENNEDY BRIDGE (S3) WATER TOWER (S2) CHENAULT BRIDGE (S1)

cc

LU

CC 

LU 

Q.

CO

O

O

LU 

O

O

o

900

600

300

J _ . I _ 1 _ !.___ ! 1 1 1 1 1

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IT)

fc

13 600

i

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CD

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£

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13

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-

-

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i i i i i

-

-

. T

fc==l ^^ C^a I"1-! r-1-!

1 1 1 I I

1 1 1 1 1

0 30 40 50 60 0 30 40 50 60 0 30 40 50 60

PERCENT REDUCTION OF SOLUBLE REACTIVE PHOSPHORUS 

EXPLANATION

o EXTREME OUTLIER 

* OUTLIER

 95th PERCENTILE T 75th PERCENTILE

 MEDIAN VALUE

 - 25th PERCENTILE 

_L 10th PERCENTILE

Figure 24. Distribution of simulated chlorophyll a concentrations at Kennedy Bridge (S3), Water Tower (S2), 

and Chenault Bridge (S1) in the Herrington Lake model for input soluble reactive phosphorus reductions from 

all sources for March 1-May 31, June 1-August 15, and August 16-September 28, 1996.

PHOSPHORUS REDUCTIONS NEEDED TO ATTAIN SELECTED TROPHIC STATE INDEXES 49
KENNEDY BRIDGE (S3) WATER TOWER (S2) CHENAULT BRIDGE (S1)

CC 

UJ I13

CC 

UJ 

Q.

co5

Up §cc 

o

2 

z

o

cc

UJ

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8

900

600

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1 1 1 1 1 1 i _L 1 1

o o o o o

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D 600

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900

CC 

UJ 

CD

U 600

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(0

AUGUST 16-

-

_

^ a a a a 

i i i i i

-

i i i i i

0 30 40 50 60 0 30 40 50 60 0 30 40 50 60

PERCENT REDUCTION OF SOLUBLE REACTIVE PHOSPHORUS

EXPLANATION

o EXTREME OUTLIER

* OUTLIER

 95th PERCENTILE T 75th PERCENTILE

MEDIAN VALUE

 | 25th PERCENTILE 

_L 10th PERCENTILE

Figure 25. Distribution of simulated chlorophyll a concentrations at Kennedy Bridge (S3), Water Tower (S2), 

and Chenault Bridge (S1) in the Herrington Lake model for input soluble reactive phosphorus reductions from 

Dix River and Clarks Run for March 1-May 31, June 1-August 15, and August 16-September 28,1996.

50 Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky
Carlson Trophic State Index for 

Chlorophyll a

Average simulated concentrations of 

chlorophyll a in Herrington Lake are also reduced as 

a result of reductions in all SRP inputs (fig. 24). The 

greatest reductions are indicated for Chenault Bridge 

(SI) during the August 16-September 28 period. As 

previously mentioned, Chenault Bridge (SI) is the 

station closest to the Dix River and Clarks Run and 

reductions in SRP from these sources would be 

expected to result in the most immediate reductions 

in chlorophyll a concentrations at this station. 

Reductions are also indicated at stations further 

downstream although the magnitude of the predicted 

reduction is less. The Carlson TSI for chlorophyll a 

resulting from the simulated alternative reductions in 

SRP inputs from all sources is given in tables 13 and 

14.

The Carlson TSI for chlorophyll a computed 

for all of the management strategies considered in 

this study would result in Herrington Lake being 

considered as hypereutrophic. On average though, 

the Herrington Lake model greatly overestimates 

chlorophyll a concentrations. Consequently, the 

Carlson TSI for chlorophyll a values shown in tables 

13 and 14 are probably greatly overestimated. The 

Carlson TSI for chlorophyll a computed from data 

collected during 1996 would result in the reservoir 

being considered eutrophic but not hypereutrophic. 

Unlike the Carlson TSI for SRP, there is little 

reduction in the Carlson TSI for chlorophyll a, even 

for simulations where SRP inputs were reduced by 

80 percent. However, because simulation of 

chlorophyll a in the Herrington Lake model is poor, 

the reduction that would occur in the Carlson TSI 

values if SRP inputs to Herrington Lake were 

reduced is probably underestimated. Reductions in 

the Carlson TSI for chlorophyll a may also be 

underestimated because of the way the model 

simulates phosphorus cycling. Phosphorus stored in 

bed sediment serves as an available source of 

phosphorus to the overlying water. Because of this 

additional source and the short time period simulated 

in the Herrington Lake model, limiting 

concentrations of phosphorus may not be achieved. 

Over time, however, as this stored phosphorus is 

removed from the reservoir, phosphorus should 

become limiting and the effects of the reduced SRP

loads to the reservoir on the Carlson TSI for 

chlorophyll a should become apparent.

As with SRP, the magnitude of the reduction in 

simulated concentrations of chlorophyll a in 

Herrington Lake when only the SRP inputs for the 

Dix River and Clarks Run are reduced is similar to 

that obtained when SRP from all inputs is reduced 

(fig. 25). Again, this is not surprising since most of 

the SRP entering Herrington Lake is from these two 

sources. The spatial and seasonal patterns of 

simulated chlorophyll a concentrations 

corresponding to reductions in SRP in only the Dix 

River and Clarks Run are nearly identical to those 

obtained from reductions in SRP from all sources. 

SRP reductions in only the Dix River and Clarks Run 

result in Carlson TSI for chlorophyll a values that 

differ little from those obtained when the reductions 

were applied to all inflows (tables 13 and 14).

SUMMARY AND CONCLUSIONS

Herrington Lake, Kentucky, which is 

impounded from the Dix River by the Dix Dam,

f\

covers a surface area of 4.6 mi and is approximately 

35 mi long. Major inflows to the reservoir are the Dix 

River and Clarks Run. Stream-discharge and waterquality data collected at these inflows and at the 

minor tributaries (Mocks Branch, Cane Run, and 

McKecknie Creek) and data from two permitteddischarge sites were used as input to a water-quality 

model for the reservoir. Samples collected from the 

Dix River and the four tributaries were analyzed for 

nutrients and physical properties. Samples collected 

in the reservoir were analyzed for algae, nutrients, 

chlorophyll a, and physical properties.

During a 2-year (1995-96) study of Herrington 

Lake to assess nutrient loading, ambient waterquality conditions varied both spatially and 

seasonally. The spatial gradients in the reservoir 

reflect the combined effect of reservoir morphology 

and flow into it. Interannual variability in nutrient 

concentrations and chlorophyll a were affected by 

the hydrology of the reservoir. During JulyOctober 1995, tributary flow into the reservoir was 

below average because of low precipitation levels, 

which in turn resulted in lower concentrations of

SUMMARY AND CONCLUSIONS 51
nutrients and chlorophyll a throughout the reservoir. 

In July 1996, runoff from a rainstorm caused elevated 

nutrient levels throughout the reservoir; the nutrient 

concentrations remained elevated for the duration of 

the summer. Although discharge affected nutrient 

concentrations, chlorophyll a levels were not affected 

during the summer of 1996. Chlorophyll a levels at 

Chenault Bridge (SI) remained high in the summer 

for both years despite the significant differences in 

discharge and precipitation; however, this does not 

eliminate the role discharge plays in phytoplankton 

dynamics.

Loads of nitrate-nitrogen (NC^-N) and soluble 

reactive phosphorus (SRP) were determined over a 

range of seasonal and hydrologic conditions. Results 

indicated that most of the nitrogen and phosphorus 

entering the reservoir originated from the Dix River 

and Clarks Run. Combined loads from both 

tributaries were estimated to contribute about 

92 percent of the SRP load into Herrington Lake. Dix 

River, the major inflow, is affected not only by 

nonpoint sources of nutrients but also by point 

sources located along its length. When determining 

point-source and nonpoint-source contributions of 

the nutrients to Herrington Lake, the Dix River was 

treated as a separate case and both types of load 

contributions are grouped together. Point-source 

total-load percentages other than those in the Dix 

River ranged seasonally from 1 to 9 percent. Totalload percentages from nonpoint sources ranged from 

11 to 29 percent. A nutrient-mass balance indicated 

that Herrington Lake has a retention rate of 

67 percent per year for phosphorus and a nitrogen 

retention rate of 31 percent per year.

A two-dimensional, laterally averaged waterquality model (CE-QUAL-W2) was used to simulate 

physical and water-quality constituents for 

Herrington Lake for the period January through 

September 1996. The model was used to simulate 

constituent transport during stratified and unstratified 

conditions, wind and temperature effects, and effects 

of nutrients on DO and phytoplankton production. 

The model simulated temperature, DO, and nitratenitrogen reasonably well (root mean square error 

(RMSE) <20 percent). However, simulations of 

soluble reactive phosphorus, ammonia-nitrogen, and 

chlorophyll a were poor (RMSE >20 percent). The 

Herrington Lake model was used to evaluate the

effect of alternative nutrient-loading reductions on 

the water-quality of Herrington Lake. These 

alternative nutrient loading reductions are 

represented by simulations in which input SRP 

concentrations were reduced at the Dix River, the 

four tributaries, and two permitted wastewatertreatment sites. The effects on phosphorus and 

chlorophyll a concentrations in the reservoir as a 

result were evaluated. Input SRP concentrations were 

reduced from 30 and 80 percent (in 10-percent 

increments).

The simulated SRP concentrations and Carlson 

Trophic State Index (TSI) values calculated from 

those concentrations were compared to evaluate the 

effectiveness of potential management strategies. 

SRP input concentration reductions of 60 percent 

resulted in a decrease of the annual TSI for 

phosphorus from 70 to 64. Reductions of 60 percent 

in only the Dix River and Clarks Run yielded similar 

results. Model simulations indicate that water quality 

in Herrington Lake may be improved through 

reductions in input SRP concentrations. There was 

little reduction in the Carlson TSI for chlorophyll a 

as a result of even 80-percent reductions of input 

concentrations of SRP; however, simulated 

concentrations of chlorophyll a are poor and the 

predicted reduction probably underestimated. 

Refinements of the model so that it would better 

simulate chlorophyll a more accurately would 

improve the Carlson TSI values calculated for 

chlorophyll a and phosphorus.

REFERENCES CITED

American Public Health Association, 1992, Standard

methods for the examination of water and wastewater 

(19th ed.): Washington, D.C., American Public Health 

Association, 1,268 p.

Bowie, G.L., Mills, W.B., Porcella, D.B., Campbell, C.L., 

Pagenkopf, J.R., Rupp, G.L., Johnson, K.M., Chan, 

P.W.H., Gherini, S.A., and Chamberlin, C.E., 1985, 

Rates, constants, and kinetics formulations in surface 

water quality modeling: U.S. Environmental 

Protection Agency, EPA/600/3-85/040, 455 p.

Carlson, R.E., 1977, A trophic state index for lakes:

Limnological Oceanography, v. 22, no. 2, p. 361-369.

52 Modeling Hydrodynamics and Water Quality in Herrington Lake, Kentucky
Chapra, S.S., 1997, Surface water-quality modeling: New 

York, McGraw-Hill, 884 p.

Cole, T.M., and Buchak, E.M., 1995, CE-QUAL-W2 A 

two dimensional, laterally averaged, hydrodynamic 

and water quality model, version 2.0: Vicksburg, 

Miss., U.S. Army Corps of Engineers [variously 

paged].

Grain, A.S., 1998, Hydrologic constraints on

phytoplankton production and nutrient assimilation 

capacity in a eutrophic Kentucky reservoir: 

Louisville, Ky., University of Louisville, M.S. thesis, 

40 p., 11 figs.

Desikachary, T.V., 1959, Cyanophyta: New York, 

Academic Press, 686 p.

Dillard, G.E., 1989, Freshwater algae of the southeastern 

United States: Berlin, J. Cramer [various parts].

FTN Associates Limited, 1998, Taylorsville Lake water 

quality model study: Little Rock, Ark., [variously 

paged] (prepared for U.S. Army Corps of Engineers, 

Louisville District).

Giorgino, M.J., and Bales, J.D., 1997, Rhodiss Lake, North 

Carolina Analysis of ambient conditions and 

simulation of hydrodynamics, constituent transport, 

and water-quality characteristics, 1993-94: U.S. 

Geological Survey Water-Resources Investigations 

Report 97-4131,62 p.

Kennedy, R.H., and Walker, W.W., 1990, Reservoir

nutrient dynamics, in Thornton, K.W., Kimmel, B.L., 

and Payne, F.E., eds., Reservoir 

Limnology Ecological perspectives: New York, 

Wiley,p. 109-132.

Kentucky Natural Resources and Environmental Protection 

Cabinet, 1984, 1984 Kentucky report to Congress on 

water quality section (305b): Frankfort, Ky., Division 

of Water [variously paged].

___1992a, 1992 Kentucky report to Congress on water 

quality section (305b): Frankfort, Ky., Division of 

Water [variously paged].

___1992b, 303(d) List of Waters for Kentucky:

Frankfort, Ky,. Division of Water [variously paged].

___1997, Kentucky Watershed Management Plan, 

accessed November 23, 1999, at URL 

http://water.nr.state.ky.us/dow/watrshd.htm.

___1998, 1998 Kentucky report to Congress on water 

quality section (305b): Frankfort, Ky., Division of 

Water [variously paged].

Kirk, J.T.O., 1983, Light and photosynthesis in aquatic 

ecosystems: Cambridge, England, Cambridge 

University Press, 401 p.

McClain, D.L., Byrd, F.D., and Brown, A.C., 1996, Water 

resources data, Kentucky, water year 1995: U.S. 

Geological Survey Water-Data Report KY-95-1, 

272 p.

___1997, Water resources data, Kentucky, water year

1996: U.S. Geological Survey Water-Data Report 

KY-96-l,286p.

Prescott, G.W, 1978, How to know the freshwater algae: 

Dubuque, Iowa, W.C. Brown Company, 293 p.

Smith, G.M., 1950, The freshwater algae of the United 

States (2d ed.): New York, McGraw-Hill, 719 p.

U.S. Army Corps of Engineers, 1994, Hydrographic 

Surveying: Washington, D.C., EM 1110-2-1003 

[variously paged].

U.S. Bureau of the Census, 1991, 1990 Census of

population and housing, summary population and 

housing characteristics, Kentucky: U.S. Department 

of Commerce, 1990 CPH-1-19, 370 p.

U.S. Environmental Protection Agency, 1977, National 

eutrophication survey Herrington Lake Boyle, 

Garrard, and Mercer Counties, Kentucky: U.S. 

Environmental Protection Agency Working Paper 

no. 353, 21 p.

___1991, Guidance for water quality-based

decisions The TMDL process: U.S. Environmental 

Protection Agency 440/4-91-001, 72 p.

U.S. Geological Survey, 1986a, Land use and land cover 

digital data from 1:250,000 and 1:100,000 scale maps: 

National Mapping Program Technical Instructions 

Data Users Guide 4, 36 p.

___1986b, National Water Summary,

1985 Hydrologic events and surface-water 

resources: U.S. Geological Survey Water-Supply 

Paper 2300, 506 p.

Walker, W.W., Jr., 1987, Empirical methods for predicting 

eutrophication in impoundments Report 4, Phase 

III Application manual: Vicksburg, Miss., 

U.S. Army Corps of Engineers, Waterways 

Experiment Station, Technical Report E-81-9 

[variously paged].

Wetzel, R.G., 1983, Limnology: Orlando, Fla., Saunders 

College Publishing, Harcourt Brace College 

Publishers, 767 p.

Whitford, L.A., and Schumacher, G.J., 1984, A manual of 

fresh-water algae: Raleigh, N.C., Sparks Press, 337 p.

REFERENCES CITED 53

APPENDIXES

Appendix 1. CE-QUAL-W2 input file for Dix River, January 1,1996 to December 31,1996

[JDAY, Julian day; SS, suspended solids; TDS, total dissolved solids; LOOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

DETRIT, detritus; SRP, soluble reactive phosphorus; NHLj-N, ammonia-nitrogen; NO3-N, nitrate-nitrogen; O2, dissolved oxygen; TIC, total inorganic carbon

concentrations in milligrams per liter]

Appendix

-* 

JDAY

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21 

22 

23

24

SS

4.67

14.9

27.78

19.48

15.25

13.89

12.04

10.11

12.15

11.14

10.8

11.98

12.76

14.09

21.89

23.6

28.01

23.99

32.72

25.9

19.18

15.65 

14.52 

31.39

27.52

TDS

97.33

187.64

253.58

216.56

190.18

178.81

162.36

145.85

164.58

155.07

152.66

161.69

165.88

178.98

233.2

245.71

260.31

246.92

298.18

248.79

214.58

194.84 

185.42 

270.74

253.28

LOOM

3.05

6.99

11.67

8.57

7.07

6.53

5.95

5.27

5.96

5.54

5.5

5.93

6.11

6.63

9.79

10.24

11.97

10.68

13.19

10.95

8.37

7.31 

6.91

12.47

11.48

ROOM

7.19

17.19

24.72

19.87

17.41

15.99

14.78

12.97

14.87

13.84

13.73

14.53

15.12

16.24

21.46

22.37

25.38

22.63

28.94

23.4

19.56

17.68 

16.91 

26.98

24.5

ALGAE

0

.01

.02

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.02

.02

.02

.02

.02

.01

.01 

.01 

.02

.02

DETRIT

0.17

.41

.66

.53

.44

.38

.34

.27

.34

.31

.29

.34

.34

.38

.59

.62

.67

.62

.74

.64

.53

.45 

.4 

.69

.65

SRP

0.119

.119

.12

.12

.12

.12

.121

.121

.121

.122

.122

.122

.123

.123

.123

.124

.131

.139

.147

.144

.142

.139 

.137 

.135

.132

NH4-N

0.04

.02

.05

.01

.01

.04

.05

.03

.04

.01

.01

.03

.02

.05

.01

.01

.01

.01

.02

.02

.02

.01 

.02 

0

.04

N03-N

1.146

1.158

1.478

1.493

1.508

1.207

1.22

1.232

1.245

1.258

1.271

1.284

1.298

1.311

1.673

1.69

1.608

1.531

1.457

1.487

1.517

1.549 

1.581 

1.613

1.647

02

7.77

14.39

10.92

7.14

15.71

12.42

16.22

14.15

13.22

13.57

10.91

12.38

9.44

11.44

11.61

9.78

9.13

9.32

11.66

13.14

14.68

15.74 

17.48 

17.26

17.39
Appendix 1. CE-QUAL-W2 input file for Dix River, January 1, 1996 to December 31,1996 Continued

[JDAY, Julian day; SS, suspended solids; TDS, total dissolved solids; LOOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

> DETRIT, detritus; SRP, soluble reactive phc 

5 concentrations in milligrams per liter]

1. JDAY x

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

SS

19.65

20.64

19.49

16.33

14.64

13.26

11.05

8.85

7.79

9.65

9.52

9.47

9.25

10.68

19.9

17.01

14.33

11.72

10.3

9.5

9.2

8.56

7.09

6.04

5.95

11.39

14.39

TDS

216.93

225.69

216.69

198.54

186.04

171.33

153.59

134.1

126.32

142.09

141.62

140.68

140.17

151.85

220.32

203.37

180.76

158.21

146.17

140.87

138.8

133.27

119.12

111.33

109.94

156.85

182.2

>sphorus; NH^

LOOM

8.64

9.06

8.61

7.62

6.92

6.34

5.53

4.78

4.5

5.17

5.16

5.11

5.04

5.49

8.7

7.8

6.65

5.84

5.28

5.11

4.95

4.75

4.28

3.82

3.67

5.74

6.81

-N, ammonia-]

ROOM

19.94

20.9

19.9

17.97

17.01

15.52

13.8

11.69

10.82

12.69

12.67

12.56

12.3

13.48

20.32

18.55

16.34

14.34

13.06

12.63

12.26

11.55

10.05

8.89

8.86

14.23

16.66

nitrogen; NC>3-

ALGAE

0.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

N, nitrate-nitrog

DETRIT

0.53

.55

.53

.47

.41

.36

.3

.25

.23

.27

.27

.26

.26

.29

.54

.47

.38

.32

.28

.26

.26

.24

.2

.19

.18

.32

.4

;en; O2, dissol

SRP

0.13

.128

.126

.124

.122

.12

.118

.116

.114

.112

.11

.108

.106

.104

.103

.107

.112

.117

.123

.128

.134

.14

.146

.153

.16

.167

.175

ved oxygen; Tl

NH4-N

0

.01

.04

.02

.02

.02

.01

.04

.02

.04

.03

.03

.03

.05

.05

.02

.02

.04

.01

.04

.01

.04

.02

.04

.03

.05

.04

1C, total morga

N03-N

1.681

1.715

1.751

1.787

1.824

1.474

1.505

1.536

1.567

1.6

1.633

1.666

1.701

1.736

2.237

2.213

1.735

1.716

1.698

1.68

1.663

1.645

1.628

1.611

1.594

1.577

1.561

me carbon; 

02

15.19

10.9

14.01

17.68

12.91

10.71

16.12

10.74

11.79

10.49

14.45

16.89

15.44

13.25

12.53

9.24

14.81

14.35

9.22

12.6

11.73

9.72

11.2

11.73

13.61

12.8

14.48
Appendix 1. CE-QUAL-W2 input file for Dix River, January 1,1996 to December 31,1996 Continued

[JDAY, Julian day; SS, suspended solids; TDS, total dissolved solids; LOOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

DETRIT, detritus; SRP, soluble reactive phosphorus; NH4-N, ammonia-nitrogen; NC^-N, nitrate-nitrogen; O2, dissolved oxygen; TIC, total inorganic carbon

concentrations in milligrams per liter]

JDAY

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

 o 75

1 76

5 77

78

SS

12.78

11.05

10.07

8.15

7.3

8.09

21.16

18.31

14.8

13.24

10.94

9.12

8.41

29.05

29.79

27.15

19.85

17.29

15.39

14.39

13.17

11.35

14.24

14.94

20.45 

17.42

18.95

TDS

166.12

154.38

144.02

130.17

120.77

129.76

231.65

210.41

186.19

170.36

153.45

136.54

132.1

260.76

264.02

250.14

219.31

205.22

190.27

182.02

169.23

156.19

179.93

189.25

222.51 

206.55

211.56

LOOM

6.18

5.54

5.22

4.59

4.35

4.56

9.42

8.21

6.94

6.26

5.51

4.83

4.68

12.21

12.31

11.2

8.69

7.84

7.11

6.8

6.24

5.7

6.65

7.03

8.86 

7.86

8.36

ROOM

15.19

13.83

12.85

11.2

10.32

11.17

21.32

19.4

17.11

15.5

13.76

11.87

11.4

25.69

25.81

23.59

20.25

18.68

17.44

16.57

15.33

14.11

16.32

17.27

20.72 

18.74

19.49

ALGAE

0.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.02

.02

.02

.01

.01

.01

.01

.01

.01

.01

.01

.01 

.01

.01

DETRIT

0.34

.31

.27

.24

.21

.24

.58

.51

.41

.36

.29

.25

.24

.67

.67

.65

.54

.49

.44

.39

.36

.31

.38

.42

.54 

.5

.52

SRP

0.182

.191

.199

.208

.218

.228

.238

.229

.22

.211

.203

.195

.187

.18

.172

.165

.159

.152

.146

.14

.134

.129

.124

.119

.114 

.109

.105

NH4-N

0.04

.04

.04

.03

.03

.03

.02

.02

.02

.01

.04

.04

.04

.04

.05

.02

.01

.05

.03

.04

.02

.04

.02

.04

.02 

.03

.01

N03-N

1.544

1.528

1.512

1.496

1.48

1.465

1.83

1.821

1.811

1.427

1.42

1.412

1.405

1.765

1.766

1.766

1.767

1.768

1.768

1.401

1.402

1.402

1.403

1.772

1.772 

1.773

1.774

02

13.35

15.42

14.51

11.31

10.52

9.12

8.34

12.59

9.16

7.23

13.96

14.26

7.87

10.71

15.19

17.81

9.63

11.63

9.91

11.53

9.83

7.39

8.58

11.5

15.85 

11.64

8.82
o 

o Appendix 1. CE-QUAL-W2 input file for Dix River, January 1,1996 to December 31,1996 Continued

[JDAY, Julian day; SS, suspended solids; TDS, total dissolved solids; LOOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

> DETRIT, detritus; SRP, soluble reactive phc 

 o concentrations in milligrams per liter]

(D

9: JDAY X

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

SS

20.76

20.68

20.06

20.58

18.67

17.1

15.5

14.19

13.47

17.49

16.87

14.86

15.97

19.22

16.28

14.49

14.33

13.55

11.6

10.56

9.87

8.95

7.37

6.87

6.01

6.55

7.3

TDS

229.95

229.19

220.65

223.45

211.29

204.89

191.79

179.53

173.6

209.35

203.29

187.51

195.44

215.8

198.49

183.7

181.92

174.29

157.92

149.56

143.86

134.67

121.88

118.49

110.53

117.6

120.7

>sphorus; NH4-N, ammonia-nitrogen; N<>3-

LDOM

9.31

9.08

8.79

8.9

8.23

7.83

7.21

6.63

6.38

7.95

7.74

6.99

7.34

8.41

7.6

6.9

6.77

6.41

5.83

5.43

5.21

4.81

4.41

4.26

3.81

4.04

4.35

ROOM

21.02

20.94

20.36

20.8

19.44

18.6

17.54

16.24

15.64

19.14

18.55

17.12

17.7

19.63

17.9

16.86

16.44

15.79

14.32

13.25

12.75

11.75

10.44

10

8.89

9.53

10.29

ALGAE

0.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

N, nitrate-nitrogen; O2, dissolved oxygen; TIC, total inorga

DETRIT

0.57

.56

.54

.54

.52

.48

.44

.38

.37

.5

.47

.41

.45

.53

.47

.4

.39

.37

.32

.28

.27

.25

.22

.2

.18

.2

.21

SRP

0.101

.096

.093

.089

.085

.082

.078

.075

.072

.069

.066

.064

.061

.059

.056

.054

.052

.05

.048

.046

.044

.042

.04

.037

.034

.032

.029

NH4-N

0.01

.03

.03

.02

.05

0

.01

.03

.05

.03

0

.03

.01

.03

.05

.02

.02

.05

.05

.04

0

.05

.01

.01

.03

.01

.02

N03-N

1.774

1.775

1.775

1.776

1.777

1.777

1.778

1.409

1.409

1.78

1.781

1.781

1.782

1.783

1.783

1.413

1.414

1.414

1.415

1.415

1.416

1.416

1.417

1.398

1.38

1.362

1.344

nic carbon; A

02

10.68

8.44

13.91

13.1

12.86

8.83

12.5

17.18

11.6

9.23

12.32

11.84

15.02

12.3

13.7

9.87

11.36

11.3

8.36

7.38

14.99

9.84

13.26

8.86

10.34

10.37

9.82
Appendix 1. CE-QUAL-W2 input file for Dix River, January 1,1996 to December 31,1996 Continued

[JDAY, Julian day; SS, suspended solids; IDS, total dissolved solids; LOOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

DETRIT, detritus; SRP, soluble reactive phosphorus; NH4-N, ammonia-nitrogen; NO3-N, nitrate-nitrogen; O2, dissolved oxygen; TIC, total inorganic carbon; 

concentrations in milligrams per liter]

JDAY

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

 o 129

1 130

a

* 131

132

SS

14.43

12.15

9.24

7.8

18.01

23

16.14

21.4

22.85

18.24

16.09

15.13

12.62

11.44

21.94

19.84

15.42

13.79

11.19

9.67

16.13

13.03

13.18

11.39

9.11

7.17

6.8

TDS

183.03

164.79

140.15

126.77

209.4

236.47

198.01

232.43

235.84

210.14

197.26

189.55

165.22

157.31

234.41

218.69

190.66

176.83

155.08

143.04

197.57

167.22

169.47

156.74

136.14

120.39

118.29

LDOM

6.82

5.98

5.02

4.54

8.02

10.04

7.51

9.76

10.02

8.18

7.43

7.04

6.08

5.81

10.01

8.69

7.17

6.47

5.57

5.2

7.5

6.22

6.25

5.72

4.82

4.31

4.24

RDOM

16.83

14.98

12.28

10.89

19.22

21.94

17.85

21.46

21.67

19.32

17.7

17.35

15.02

14.25

21.62

20.15

17.45

15.88

13.89

12.7

17.7

15.26

15.41

14.17

11.84

10.26

9.98

ALGAE

0.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

DETRIT

0.4

.34

.26

.24

.51

.61

.46

.59

.6

.51

.46

.44

.34

.32

.59

.54

.44

.37

.31

.27

.46

.34

.36

.32

.25

.21

.2

SRP

0.027

.025

.023

.021

.02

.018

.017

.015

.014

.015

.015

.015

.016

.016

.017

.017

.017

.018

.018

.019

.019

.02

.021

.021

.022

.022

.023

NH4-N

0.01

.04

.04

.04

0

.03

.05

.01

.04

0

.04

.04

.02

.02

.04

.05

.03

0

0

.02

.04

.04

.03

0

.03

.02

.04

N03-N

1.326

1.309

1.292

1.275

1.588

1.568

1.547

1.527

1.507

1.517

1.528

1.539

1.228

1.237

1.573

1.584

1.595

1.272

1.282

1.291

1.641

1.309

1.319

1.328

1.338

1.347

1.357

02

9.69

10.86

11.9

9.87

12.89

3.88

12.58

10.63

14

9.59

9.63

7.88

10.88

12.07

13.33

10.1

14.77

11.6

15.85

8.21

9.92

8.97

7.53

8.35

12.08

8.24

14.9
> D

*

Appendix 1. CE-QUAL-W2 input file for Dix River, January 1,1996 to December 31,1996 Continued

[JDAY, Julian day; SS, suspended solids; TDS, total dissolved solids; LDOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

DETRIT, detritus; SRP, soluble reactive phosphorus; NH4-N, ammonia-nitrogen; NC^-N, nitrate-nitrogen; O2, dissolved oxygen; TIC, total inorganic carbon; A

concentrations in milligrams per liter]

a JDAY x

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

SS

5.77

4.61

5.88

13.2

7.97

5.63

4.15

3.88

3.37

3.04

2.62

2.6

2.07

21.07

30.74

33.24

31.92

23.17

16.47

13.77

10.79

10.66

10.31

8.24

6.04

5.07

11.92

TDS

105.93

96.75

108.12

170.17

129.55

103.71

91.14

84.67

76.39

71.36

65.78

65.1

60.47

231.41

265.28

299.28

287.16

239.32

199.91

175.88

152.13

151.27

146.91

130.64

112.3

100.69

161.49

LDOM

3.37

3.03

3.67

6.26

4.55

3.35

2.94

2.78

2.5

2.26

1.97

1.97

1.64

9.42

12.35

13.58

12.89

10.12

7.66

6.44

5.49

5.48

5.31

4.59

3.83

3.15

5.9

ROOM

8.52

7.03

8.82

15.43

11.1

8.31

6.46

5.93

5.23

5.02

4.72

4.67

3.99

21.22

25.85

29.31

28.04

22.27

18.25

15.83

13.71

13.34

13.18

11.2

9.01

7.69

14.52

ALGAE

0.01

0

.01

.01

.01

.01

0

0

0

0

0

0

0

.01

.02

.02

.02

.01

.01

.01

.01

.01

.01

.01

.01

0

.01

DETRIT

0.18

.16

.18

.36

.24

.18

.15

.14

.13

.12

.1

.1

.08

.58

.68

.79

.73

.61

.47

.37

.29

.29

.28

.24

.19

.17

.33

SRP

0.023

.024

.025

.025

.026

.027

.027

.028

.029

.03

.031

.031

.032

.033

.034

.035

.036

.037

.038

.039

.04

.041

.042

.043

.044

.045

.047

NH4-N

0.02

.01

.05

.03

.01

.01

.05

.02

.04

.03

.01

.01

.03

.03

.02

.05

.05

.04

.01

.02

.03

.03

.03

.01

.04

.02

.01

N03-N

1.366

1.376

1.386

1.396

1.406

1.416

1.426

1.436

I Ml

1.457

1.467

1.478

1.489

1.893

1.906

1.92

1.947

1.974

2.001

1.607

1.63

1.652

1.675

1.699

1.722

1.746

1.77

02

11.31

10.19

9.56

8.11

10.53

10.37

16.97

11.4

10.99

10.53

8.98

10.06

8.77

12.29

11.53

6.78

7.06

11.27

10.13

10.61

12.37

13.18

9.96

6.94

9.53

8.4

12.42
Appendix 1. CE-QUAL-W2 input file for Dix River, January 1,1996 to December 31,1996 Continued

[JDAY, Julian day; SS, suspended solids; TDS, total dissolved solids; LOOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

DETRIT, detritus; SRP, soluble reactive phosphorus; NH4-N, ammonia-nitrogen; NO3-N, nitrate-nitrogen; O2, dissolved oxygen; TIC, total inorganic carbon

concentrations in milligrams per liter]

JDAY

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

3 183 

I 184

* 185

186

SS

17.11

17.05

20.91

27.91

20.85

16.43

13.29

10.16

7.48

5.88

7.34

6.68

4.88

4.05

3.42

3.19

6.28

4.26

3.77

2.97

2.47

1.98

1.3

1.13 

1.21

2.17

2.51

TDS

204.99

204.36

230.61

258

230.51

198.66

171.39

145.87

125.24

108.09

121.81

117.85

97.91

89.81

78.46

73.14

115.04

93.06

82.98

70.72

64.91

56

46.75

40.44 

44.96

62.46

65.01

LOOM

7.84

7.8

9.38

11.9

9.31

7.65

6.36

5.28

4.48

3.49

4.39

4.17

3.11

2.88

2.54

2.33

3.94

2.94

2.71

2.25

1.85

1.57

1.21

.88 

1.19

1.67

1.94

ROOM

18.68

18.56

21.14

24.83

21.1

18.03

15.54

13

10.55

8.61

10.38

9.82

7.31

6.29

5.26

5.1

9.25

6.81

5.83

4.95

4.29

3.74

2.95

2.28 

2.74

4.01

4.41

ALGAE

0.01

.01

.01

.02

.01

.01

.01

.01

.01

.01

.01

.01

0

0

0

0

.01

0

0

0

0

0

0

0 

0

0

0

DETRIT

0.49

.48

.58

.66

.57

.47

.37

.27

.22

.18

.22

.2

.17

.14

.13

.12

.19

.15

.14

.11

.09

.07

.06

.05 

.06

.08

.1

SRP

0.048

.049

.051

.052

.053

.055

.056

.058

.059

.061

.062

.064

.066

.068

.069

.071

.073

.075

.077

.079

.081

.084

.086

.088 

.091

.093

.095

NH4-N

0.03

0

.03

.04

.02

.01

.05

.03

0

.01

.02

.02

.04

.02

.03

.03

.03

.05

.03

.02

.01

.05

.01

.02 

.02

.02

.04

N03-N

2.266

2.298

2.33

2.362

2.395

2.429

1.95

1.977

2.005

2.033

2.061

2.09

2.119

2.148

2.178

2.209

2.239

2.271

2.302

2.334

2.367

2.4

2.433

2.467 

2.501

2.536

2.571

02

10.15

6.68

10.35

11.95

12.21

5.98

13.21

8.68

11.22

10.94

9.63

7.53

10.82

11.68

8.34

7.14

8.88

9.06

5.97

10.5

9.78

7.25

10.37

6.01 

10.03

8.78

9.42
2 Appendix 1. CE-QUAL-W2 input file for Dix River, January 1,1996 to December 31,1996 Continued

[JDAY, Julian day; SS, suspended solids; TDS, total dissolved solids; LOOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

> DETRIT, detritus; SRP, soluble reactive phc 

 o concentrations in milligrams per liter]

(D

9: JDAY X

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

SS

1.76

.94

.79

.65

.52

.38

.34

.28

.22

23.21

24.43

10.61

6.25

27.86

37.55

35.15

20.59

15.62

12.91

10.1

10.6

7.43

6.42

8.87

9.14

6.98

5.73

TDS

50.55

31.79

25.84

18.15

12.87

12.53

9.34

8.14

6.99

242.66

247.66

150.37

1 14.49

257.98

302

301.77

224.41

193.94

166.78

145.67

149.97

124.9

115.88

134.3

137.28

118.62

105.74

>sphorus; NH4-N, ammonia-nitrogen; NO3-

LDOM

1.35

.83

.65

.37

.24

.17

.12

.11

.09

10.14

10.68

5.43

3.93

11.9

14.54

13.63

9.01

7.26

6.18

5.25

5.43

4.48

3.96

4.79

4.87

4.28

3.37

RDOM

3.29

2.09

1.59

1.48

1.15

1.13

.53

.3

.22

22.29

22.86

13.32

9.24

24.74

34.62

33.01

20.89

17.57

15.26

12.95

13.31

10.54

9.41

11.71

11.99

10.02

8.45

ALGAE

0

0

0

0

0

0

0

0

0

.01

.02

.01

.01

.02

.02

.02

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

.01

N, nitrate-nitrogen; O2, dissol

DETRIT

0.06

.04

.03

.02

.01

.01

0

0

0

.61

.63

.29

.19

.66

.98

.87

.55

.45

.34

.27

.29

.22

.19

.25

.26

.2

.18

SRP

0.098

.101

.103

.106

.109

.112

.115

.118

.121

.124

.128

.131

.135

.138

.142

.146

.15

.153

.157

.161

.164

.168

.172

.176

.18

.185

.189

ved oxygen; TIC, total inorgai

NH4-N

0

0

.04

0

0

.01

0

.03

0

0

0

.04

.03

0

.04

.05

.03

.04

.04

.05

0

.02

0

.04

.01

.04

.03

N03-N

2.607

2.644

2.68

2.718

2.755

2.794

2.833

2.872

2.912

3.728

3.78

3.035

3.078

3.94

3.995

4.05

4.107

4.033

3.137 '

3.08

3.025

2.97

2.917

2.864

2.812

2.762

2.712

nic carbon; 

02

7.9

9.53

9.05

7.11

6.58

9.6

8.04

7.81

8.6

7.16

11.88

12.72

8.01

4.68

8.24

11.83

4.85

8.16

11.59

8.11

7.99

10.53

8.3

6.83

10.13

10.51

9.84
Appendix 1. CE-QUAL-W2 input file for Dix River, January 1,1996 to December 31,1996 Continued

[JDAY, Julian day; SS, suspended solids; IDS, total dissolved solids; LOOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

DETRIT, detritus; SRP, soluble reactive phosphorus; NH4-N, ammonia-nitrogen; NO3-N, nitrate-nitrogen; O2, dissolved oxygen; TIC, total inorganic carbon

concentrations in milligrams per liter]

JDAY

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

 o 237 

| 238 

* 239

240

SS

4.58

4.08

5.45

3.93

3.28

2.96

2.5

11.29

4.77

3.44

13.45

17.44

10.09

5.86

4.09

11.9

13.81

7.42

4.25

3.56

3.75

3.41

2.89

2.46 

1.95 

1.2

3.36

TDS

96.68

89.85

102.31

86.01

73.48

67.32

64.95

155.89

97.66

78.62

171.75

207.46

145.15

107

90.86

160.77

178.78

123.48

92.2

78.98

81.45

77.48

65.95

64.6 

54.51 

42.87

73.77

LOOM

3.02

2.88

3.3

2.8

2.34

2.07

1.87

5.69

3.09

2.55

6.38

7.87

5.25

3.46

2.88

5.89

6.51

4.45

2.94

2.56

2.69

2.52

2.02

1.83 

1.57 

1.12

2.41

ROOM

6.94

6.38

8.18

6.1

5.16

4.89

4.36

14.07

7.2

5.28

15.63

18.99

12.91

8.61

6.39

14.51

15.95

10.48

6.66

5.38

5.6

5.25

4.83

4.24 

3.72 

2.66

5.17

ALGAE

0

0

0

0

0

0

0

.01

0

0

.01

.01

.01

.01

0

.01

.01

.01

0

0

0

0

0

0 

0 

0

0

DETRIT

0.16

.15

.17

.14

.12

.11

.1

.31

.17

.13

.37

.5

.27

.18

.15

.33

.37

.22

.15

.13

.14

.13

.11

.09 

.06 

.05

.12

SRP

0.193

.198

.203

.207

.212

.217

.222

.227

.233

.238

.244

.25

.255

.261

.268

.274

.28

.287

.294

.3

.307

.315

.322

.33 

.337 

.345

.353

NH4-N

0.01

.03

.04

.03

.01

.02

.01

.04

.05

.02

0

.03

.02

.01

.03

.04

.03

.03

.03

.02

.04

.05

.01

.03

.02 

.04

.03

N03-N

2.663

Z.615

2.568

2.522

2.477

2.432

2.388

2.345

2.303

2.261

2.221

2.753

2.141

2.103

2.065

2.028

1.991

1.955

1.92

1.886

1.852

1.818

1.786

1.753 

1.722 

1.691

1.66

02

7.39

9.61

12.26

7.71

8.42

9.06

7.88

9.95

9.75

5.03

8.56

5.82

7.22

8.32

9.58

6.07

11

9.11

8.94

7.22

10.37

9.98

7.39

7.05 

9.16 

8.21

6.24

O) 

01
Appendix 1. CE-QUAL-W2 input file for Dix River, January 1,1996 to December 31,1996 Continued

[JDAY, Julian day; SS, suspended solids; TDS, total dissolved solids; LOOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

DETRIT, detritus; SRP, soluble reactive phosphorus; NH4-N, ammonia-nitrogen; NO3-N, nitrate-nitrogen; O2, dissolved oxygen; TIC, total inorganic carbon; A

 p concentrations in milligrams per liter] 

§

ft JDAY

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

SS

3.86

2.51

1.34

1.18

.81

.7

.97

.79

.69

.62

.55

1.99

2.4

1.2

1.78

.94

.65

.37

8.84

19.22

13.07

7.11

4.55

3.86

3.36

3.1

2.9

TDS

83.56

65.04

48.74

40.53

28.44

24.08

34.32

26.3

23.42

13.57

13.34

56.06

63.69

40.72

53.44

30.56

21.2

9.87

134

216.42

169.03

119.16

96.05

83.37

75.68

72.53

66.05

LOOM

2.73

1.96

1.28

1.02

.7

.49

.84

.68

.49

.28

.27

1.58

1.76

1.08

1.51

.8

.49

.14

4.76

8.49

6.23

4.28

2.97

2.71

2.43

2.33

2.04

ROOM

5.87

4.5

3.12

2.59

1.79

1.58

2.1

1.66

1.55

1.32

1.22

3.8

4.24

2.62

3.66

1.92

1.51

.68

11.66

19.77

15.27

10.11

6.88

5.84

5.19

5.09

4.86

ALGAE

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

.01

.01

.01

.01

0

0

0

0

0

DETRIT

0.14

.1

.06

.05

.03

.03

.04

.03

.02

.02

.02

.07

.09

.05

.06

.04

.02

.01

.25

.53

.35

.2

.16

.14

.13

.12

.11

SRP

0.362

.37

.379

.388

.397

.406

.416

.425

.435

.446

.456

.467

.478

.489

.5

.512

.524

.537

.549

.562

.575

.589

.603

.617

.631

.646

.661

NH4-N

0.01

.04

.03

.04

.01

.01

.04

0

.05

.03

.04

.02

.05

.05

.03

.01

.02

.04

.04

.03

.01

.03

.03

.02

.03

.02

.01

N03-N

1.63

1.601

1.572

1.544

1.516

1.489

1.462

1.436

1.41

1.384

1.359

1.335

1.311

1.287

1.264

1.241

1.219

1.197

1.176

1.457

1.134

1.113

1.093

1.073

1.054

1.035

1.016

02

6.16

7.93

11.08

7.08

5.78

7.67

9.27

8.16

10.16

9.59

10.17

13.2

8.3

9.79

12.85

7.23

5.8

7.63

6.63

10.09

10.02

8.22

10.27

7.42

11.82

10.51

7.55
Appendix 1. CE-QUAL-W2 input file for Dix River, January 1,1996 to December 31,1996 Continued

[JDAY, Julian day; SS, suspended solids; TDS, total dissolved solids; LOOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

DETRIT, detritus; SRP, soluble reactive phosphorus; NH4-N, ammonia-nitrogen; NOs-N, nitrate-nitrogen; O2, dissolved oxygen; TIC, total inorganic carbon

concentrations in milligrams per liter]

 a 

1

Q. x"

JDAY

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291 

292

293

294

SS

2.28

1.76

1.8

31.56

.07

1.23

1.01

1.34

11.84

27.49

18.07

13.14

9.25

8.37

7.8

7.23

6.13

6.2

6.12

6.13

5.34

5.41

3.94

3.99

5.27

6.4

5.26

TDS

63.6

51.17

54.08

278.61

5.06

46.42

40.16

49.2

158.62

241.58

200.05

166.69

140.25

132.03

126.49

120.53

113.57

114.18

112.92

113.12

101.9

102.04

89.3

89.51 

101.24

115.8

101.09

LDOM

1.7

1.49

1.52

12.74

.02

1.21

.85

1.34

5.87

11.37

8.05

6.23

5.07

4.67

4.53

4.31

3.9

3.93

3.83

3.87

3.24

3.3

2.82

2.88 

3.18

3.95

3.16

RDOM

4.06

3.31

3.7

28.04

.12

2.75

2.11

3.24

14.36

24.2

19.3

15.31

12.37

11.33

10.87

10.29

9.16

9.16

9.13

9.15

7.97

8.08

6.2

6.27 

7.81

9.39

7.74

ALGAE

0

0

0

.02

.01

0

.02

.02

.01

.01

.01

.01

.01

.01

.01

.01

0

.01

.01

.01

.01

.03

0

.01 

.01

.01

.03

DETRIT

0.08

.06

.06

.69

.28

.04

.31

.3

.15

.12

.23

.73

.37

.05

.52

.28

.28

.21

.26

.09

.2

.81

.7

.45 

.36

.6

.54

SRP

0.677

.693

.709

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725 

.725

.725

.725

NH4-N

0.04

.05

.03

0

.03

.01

.04

.01

.02

.05

.02

.03

.02

.05

.02

.04

.01

.02

.04

0

0

0

.02

0 

.04

.02

.01

N03-N

0.998

.98

.963

.945

1.193

1.193

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945 

.945

.945

.945

02

7.23

10

6.36

7.24

6.78

11.33

11.45

9.42

6.49

7.04

9.73

7.92

13.8

11.93

12.37

9.15

8.4

9.79

12.12

8.05

8.37

9.35

6.89

9.92 

6.32

9.57

12.6
Appendix 1. CE-QUAL-W2 input file for Dix River, January 1,1996 to December 31,1996 Continued

[JDAY, Julian day; SS, suspended solids; TDS, total dissolved solids; LOOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

> DETRIT, detritus; SRP, soluble reactive phc 

 § concentrations in milligrams per liter]

S: JDAY X

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

SS

3.92

3.74

3.65

2.03

10.63

8.51

5.88

5.18

5.31

4.5

6.57

9.2

7.12

5.96

6.49

21.9

18.14

14

12.45

21.28

18.8

15.37

14.04

12.73

10.52

9.44

8.77

TDS

85.97

80.76

80.43

56.33

150.46

132.73

108.1

100.87

101.54

94.34

117.65

138.46

119.68

110.51

116.85

225.07

200.9

172.03

163.13

221.77

204.85

183.94

172.27

164.59

149.3

140.61

133.93

(sphorus; Nffy

LOOM

2.79

2.64

2.63

1.63

5.45

4.72

3.53

3.16

3.18

2.97

4.12

4.92

4.28

3.73

4

9.86

8.14

6.58

6.01

9.44

8.25

7.11

6.6

6.1

5.42

5.08

4.76

-N, ammonia-nitrogen; NC^-

RDOM

6.06

5.48

5.45

3.93

13.32

11.49

8.68

7.73

7.91

6.83

9.54

12.19

10.18

8.87

9.5

21.59

19.31

16.02

14.99

21.33

19.44

17.43

16.06

15.12

13.21

12.42

11.64

ALGAE

0.01

.02

0

.04

.01

.03

.02

.03

.01

0

0

.02

.03

.01

.02

.03

.04

.02

.01

.02

.04

.02

.04

0

.03

.03

.03

N, nitrate-nitrogen; O2, dissol

DETRIT

0.26

.51

.2

.18

.44

.09

.25

.05

.4

.22

.53

.55

.3

.52

.53

.64

.06

.35

.41

.43

.77

.34

.23

.11

.55

.38

.19

SRP

0.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

ved oxygen; T!

NH4-N

0.03

.03

.03

.04

.02

.04

.01

.02

.03

.03

.03

.02

.03

.04

.03

.03

.01

.02

.04

.02

.03

.02

.02

.02

.04

0

.04

1C, total inorga

N03-N

0.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

.945

1.193

1.193

1.193

.945

.945

.945

.945

.945

.945

.945

nic carbon; 

02

9.55

11

13.5

13.41

10.87

11.43

10.66

10.1

12.23

11.09

7.58

12.69

13.01

10

16.73

6.12

13.4

10.92

12.07

13.08

12.27

14.59

8.38

9.2

13.35

8.71

11.06
Appendix 1. CE-QUAL-W2 input file for Dix River, January 1,1996 to December 31,1996 Continued

[JDAY, Julian day; SS, suspended solids; TDS, total dissolved solids; LOOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

DETRIT, detritus; SRP, soluble reactive phosphorus; NH4-N, ammonia-nitrogen; NO3-N, nitrate-nitrogen; O2, dissolved oxygen; TIC, total inorganic carbon

concentrations in milligrams per liter]

JDAY

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

 o 345

1 346

a

* 347

348

SS

7.85

7.8

7.41

7.14

6.74

10.31

8.71

8.52

8.26

8.46

7.83

7.56

7.34

6.46

5.7

5.5

5.59

5.79

4.62

4.13

4.85

5.03

5

4.17 

3.6

3.87

3.89

TDS

129.1

126.61

122.78

119.95

118.26

146.26

133.35

132.98

130.99

132.52

128.28

126.03

121.36

116.26

104.69

103.56

103.61

106.44

97.24

91

97.79

100.31

99.09

91.63 

80.27

83.91

84.78

LOOM

4.55

4.54

4.43

4.3

4.23

5.3

4.76

4.72

4.62

4.71

4.55

4.5

4.36

3.97

3.36

3.32

3.32

3.39

3.04

2.91

3.11

3.15

3.15

2.94 

2.57

2.74

2.78

ROOM

10.96

10.87

10.45

10.24

9.94

13.14

11.6

11.52

11.21

11.41

10.93

10.55

10.36

9.42

8.43

8.24

8.29

8.53

7.15

6.45

7.21

7.46

7.39

6.52 

5.42

5.91

6.01

ALGAE

0.04

.01

.03

.01

.02

.03

0

.02

.04

.02

.02

.01

.03

.02

0

.04

.02

.01

.01

.04

.03

.02

.04

.01 

.04

.03

.01

DETRIT

0.31

.14

.35

.26

:2

.39

.16

.42

.23

.07

.07

.37

.02

.13

.19

.39

.16

.36

.4

.39

.12

.11

.3

.01 

.18

.28

.44

SRP

0.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725 

.725

.725

.725

NH4-N

0.02

.02

.01

.02

.04

0

.03

.01

.04

.04

.01

.04

.04

.01

.03

.03

.02

.03

.04

.03

.03

.02

.05

.03 

.03

.02

.01

N03-N

1.193

1.193

1.193

1.193

1.193

1.193

.945

1.193

1.193

1.193

1.193

.945

1.193

1.193

1.193

1.193

1.193

.945

.945

.945

.945

.945

.945

.945 

.945

1.193

.945

02

16.75

7.09

12.38

8.33

12.23

9.85

13.97

11.15

9.43

10.15

13.04

8.7

7.8

9.58

12.79

7.32

11.24

9.87

14.06

12.74

11.65

17.23

11.18

8.64 

8.77

10.83

13.86
Appendix 1. CE-QUAL-W2 input file for Dix River, January 1,1996 to December 31,1996 Continued

[JDAY, Julian day; SS, suspended solids; TDS, total dissolved solids; LOOM, labile dissolved organic matter; ROOM, refractive dissolved organic matter;

> DETRIT, detritus; SRP, soluble reactive pta 

 o concentrations in milligrams per liter]

(0

& JDAY X

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

SS

7.66

5.82

16.68

25.84

21.4

17.95

15.5

14.06

12.78

11.23

10.37

9.77

9.15

9.01

8.33

8.32

TDS

126.07

106.77

192.21

236.13

222.47

198.77

187.14

172.9

165.11

155.51

147.93

143.27

138.22

135.09

131.31

131.26

wphorus; NH4

LOOM

4.5

3.46

7.73

10.77

9.68

7.95

7.23

6.62

6.16

5.61

5.34

5.2

4.9

4.82

4.67

4.66

-N, ammonia-nitrogen; NO3-

RDOM

10.67

8.57

18.37

23.04

21.39

19.21

17.55

16.1

15.14

13.89

13.21

12.72

12.04

11.83

11.26

11.23

ALGAE

0.01

.02

.02

0

.02

.01

.02

0

.01

.03

.03

0

.02

.01

.01

.01

N, nitrate-nitrogen; O2, dissolved oxygen; TIC, total inorga

DETRIT

0.31

.23

.5

.06

.15

.23

.31

.34

.38

.16

.29

.1

.39

.64

.23

.07

SRP

0.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

.725

NH4-N

0.04

.05

.03

.05

.03

.03

.04

.05

.02

.03

.01

0

.04

.01

.01

.04

N03-N

0.945

.945

1.193

1.193

1.193

1.193

.945

.945

.945

1.193

1.193

1.193

1.193

.945

.945

.945

nic carbon; A

02

9.34

13.73

11.64

14.07

15.68

17.49

13.13

16.99

17.07

16.11

13.45

9.7

11.42

8.09

14.87

11.75
Appendix 2. Chemical kinetic-rate coefficients and hydraulic and thermal parameters specified as model 

input, Herrington Lake, Kentucky, 1996

[m, meter; nv\m/g), cubic meter per meter per gram; --, not applicable; *, dimensionless parameter, m/d, meter per day; 

watts/m2, watts per square meter; °C, degrees Celsius; SOD, streambed oxygen demand; BOD, biological oxygen demand; 

g/m, gram per meter; mg/L, milligram per liter; gO2m2/d, grams of oxygen per square meter per day; >, greater than; 

m° 5/s, meter to the half power per second; m2/s, square meter per second]

Parameter 

abbreviation

EXH20

EXSS

Parameter

Light-extinction 

coefficient for pure 

water (m" 1 )

Light-extinction 

coefficient for 

suspended solids

Computational 

purpose

Amount of solar radiation absorbed in 

the surface layer

Amount of solar radiation absorbed by 

total suspended material

Value in 

Herrington 

Lake 

model

0.49

.10

Values from 

1 Cole and 

Buchak, 

1995

0.18-4.0

.10

Values from 

Giorgino 

and Bales, 

1997

0.5

--

EXOM Light-extinction

coefficient for organic 

solids (m3 (m/g))

BETA Fraction of incident solar 

radiation absorbed at 

water surface

Amount of solar radiation absorbed by .27 

organic material

Amount of solar radiation absorbed in *.45 

the surface layer

.17

*.45

.2

*.3

SSS

AG

AM

AE

AR

AS

ASAT

APOM

Suspended solids settling 

rate (m/d)

Algal growth rate (d" 1 )

Algal mortality rate (d" 1 ) 

Algal excretion rate (d" 1 )

Settling rates and sediment

accumulation on reservoir bottom

Maximum gross algal-production rate, 

uncorrected for respiration, 

mortality, excretion, or settling; 

temperature dependent

Maximum algal-mortality rate; 

temperature dependent

Maximum algal-photorespiration rate, 

which becomes labile dissolved 

organic matter

Algal dark-respiration Maximum algal dark-respiration rate 

rate(d' 1 )

Algal settling rate (m/d)

Saturation light intensity 

(watts/m2)

Fraction of algal biomass 

lost by mortality to 

detritus

Representative settling velocity for 

algal assemblages

Saturation light intensity at maximum 

algal-photosynthesis rate

Detritus and dissolved organic-matter 

concentrations; remaining biomass 

becomes labile dissolved organic 

matter

1.30

1.56

.01

.005

.01

.14

150

*.8

.86 - 860

1.1

.01 - .03

.014 - .44

.01 - 92

.0-30

150

*.8

2.0

1.9

.09

.005

.005

.10

150

*.8

ATI Lower temperature for 

algal growth (°C)

AKI Fraction of algal growth 

at lower temperature

Algal-growth rate as a function of water 10 

temperature

Algal-growth rate as a function of water *. 1 

temperature

10 10

Appendix 2 71
Appendix 2. Chemical kinetic-rate coefficients and hydraulic and thermal parameters specified as model 

input, Herrington Lake, Kentucky, 1996 Continued

[m, meter; m3(m/g), cubic meter per meter per gram; --, not applicable; *, dimensionless parameter, m/d, meter per day; 

watts/m2, watts per square meter; °C, degrees Celsius; SOD, streambed oxygen demand; BOD, biological oxygen demand; 

g/m, gram per meter; mg/L, milligram per liter; gO2m2/d, grams of oxygen per square meter per day; >, greater than; 

m°-5/s, meter to the half power per second; m2/s, square meter per second]

Parameter 

abbreviation Parameter Computational purpose

Value in

Herrington

Lake

model

Values from

1 Cole and

Buchak,

1995

Values from

Giorgino

and Bales,

1997

AT2 Lower temperature for 

maximum algal 

growth (°C)

AK2 Fraction of maximum 

growth at lower 

temperature

AT3 Upper temperature for 

maximum algal 

growth (°C)

AK3 Fraction of maximum 

growth at upper 

temperature

AT4 Upper temperature for 

algal growth (°C)

AK4 Fraction of algal growth 

at upper temperature

LDOMDK Labile dissolved organicmatter-decay rate (d" 1 )

LRDDK Labile to refractory 

decay rate (d" 1 )

RDOMDK Maximum refractory 

dissolved organicmatter-decay rate (d' 1 )

LPOMDK Detritus decay rate (d'')

POMS Detritus settling velocity 

(m/d)

Algal-growth rate as a function of water 30 

temperature

Algal-growth rate as a function of water *.99 

temperature

Algal-growth rate as a function of water 35 

temperature

Algal-growth rate as a function of water *.99 

temperature

Algal-growth rate as a function of water 40 

temperature

Algal-growth rate as a function of water *. 1 

temperature

Dissolved-oxygen loss and production .02 

of inorganic carbon, ammonium, and 

phosphate from algal decay; 

temperature dependent

Transfer of labile to refractory .001 

dissolved organic matter

Dissolved-oxygen loss and production .001 

of inorganic carbon, ammonium, and 

phosphate from decay of refractory 

dissolved organic matter; 

temperature dependent

Dissolved-oxygen loss and production .04 

of inorganic carbon, ammonium, and 

phosphate from decay paniculateorganic matter; temperature 

dependent

Loss of paniculate organic matter to .35 

bottom sediment

30

*.99

35

*.99

40

22

.01 - .63

.001

.001

.001-.111

'.99

22.5

*.95

35

.04

.005

.001

.002

.001 - 20.0 2.5

OMT1 Lower temperature for 

organic matter 

decay (°C)

OMK1 Fraction of organic

matter decay at lower 

temperature

Organic-matter decay as a function of 4.0 

temperature

Organic-matter decay as a function of *. 1 

temperature

4.0 5.0

".05

72 Appendix 2
Appendix 2. Chemical kinetic-rate coefficients and hydraulic and thermal parameters specified as model 

input, Herrington Lake, Kentucky, 1996 Continued

[m, meter; m3(m/g), cubic meter per meter per gram; , not applicable; *, dimensionless parameter, m/d, meter per day; 

watts/m2, watts per square meter; °C, degrees Celsius; SOD, streambed oxygen demand; BOD, biological oxygen demand; 

g/m, gram per meter; mg/L, milligram per liter; gO2m2/d, grams of oxygen per square meter per day; >, greater than; 

m°'5/s, meter to the half power per second; m2/s, square meter per second]

Parameter 

abbreviation Parameter Computational purpose

Value in

Herrington

Lake

model

Values from

1 Cole and

Buchak,

1995

Values from

Giorgino

and Bales,

1997

OMT2 Lower temperature for 

maximum organic 

matter decay (°C)

Organic-matter decay as a function of 

temperature

20.0 20.0 25.0

OMK2 Fraction of maximum 

organic matter decay 

at lower temperature

SDK Sediment decay rate (d~')

Organic-matter decay as a function of *.99 

temperature

Decay rate of organic matter in bed .06 

sediments

*.99

.06

'.95

.015

FSOD Fraction of SOD

SOD Sediment oxygen 

demand by 20 

segments (gO2m2/d)

Sediment oxygen-demand function

Factor for assessing sediment oxygen 

demand at various strata and 

computational segments

.9 

.1-5.8 .0

KBOD 5-day chemical oxygendemand-decay rateEffects of BOD loading on dissolved 

oxygen

.25 .25 .15

TBOD BOD temperature-rate 

coefficient

Adjusts 5-day BOD decay rate at 20°C 

to ambient temperature

* 1.047 * 1.047 * 1.0147

RBOD Ratio of 5-day BOD to 

ultimate BOD

Effects of BOD loading on dissolved 

oxygen

*1.85 *1.85 *1.20

PO4R Release rate of 

phosphorus from 

bottom sediments

Phosphorus balance; computed as a 

fraction of the sediment oxygen 

demand

*.015 *0 - .30 '.005

PARTP Phosphorus partitioning 

coefficient

Describes sorption of phosphorus onto 

suspended solids

.02 1.2 3.0

AHSP Algal half-saturation 

constant for 

phosphorus (g/m)

The phosphorus concentration at which 

the uptake rate is one-half the 

maximum uptake rate; upper 

concentration at which algal growth 

is proportional to phosphorus 

concentration

.005 .001-1.520 .005

NH4R Release rate of ammonia 

from bottom 

sediments

Nitrogen balance; computed as a 

fraction of the sediment oxygen 

demand

*.08 *0-.4 *.003

NH4DK Ammonia-decay 

ratetd' 1 )

Rate at which ammonia is oxidized to 

nitrate

.12 .09-1.30 .20

AHSN Algal half-saturation 

constant for ammonia

Nitrogen concentration at which the 

algal uptake rate is one-half the 

maximum uptake rate

*.044 *.006 - 4.34 *.014

Appendix 2 73
Appendix 2. Chemical kinetic-rate coefficients and hydraulic and thermal parameters specified as model 

input, Herrington Lake, Kentucky, 1996 Continued

[m, meter; m3(m/g), cubic meter per meter per gram; -, not applicable; *, dimensionless parameter, m/d, meter per day; 

watts/m2, watts per square meter; °C, degrees Celsius; SOD, streambed oxygen demand; BOD, biological oxygen demand; 

g/m, gram per meter; mg/L, milligram per liter; gO2m2/d, grams of oxygen per square meter per day; >, greater than; 

m°'5/s, meter to the half power per second; m2/s, square meter per second]

Parameter 

abbreviation Parameter Computational 

purpose

Value in

Herrington

Lake

model

Values from

1 Cole and

Buchak,

1995

Values from

Giorgino

and Bales,

1997

PARTN Ammonia partitioning

coefficient for sorption 

onto suspended solids

A function of conversion of ammonia to 

nitrate or sorption to suspended 

solids

1.0 1.0

NH4T1 Lower temperature for 

ammonia decay (°C)

Ammonia nitrification as a function of 

temperature

5.0 5.0 5.0

NH4K1 Fraction of nitrification at 

lower temperature

Ammonia nitrification as a function of 

temperature

*.10

NH4T2 Lower temperature for 

maximum ammonia 

decay (°C)

Ammonia nitrification as a function of 

temperature

20.0 20.0 25.0

NH4K2

NO3DK

Fraction of maximum 

nitrification at lower 

temperature

Nitrate decay rate (d" 1 )

Ammonia nitrification as a function of *.99 

temperature

Rate at which nitrate is denitrified; .202 

temperature dependent

*.99

.05-.15

*.99

.15

NO3T1 Lower temperature for 

nitrate decay (°C)

Denitrification as a function of 

temperature

5.0 5.0 5.0

NO3K1 Fraction of denitrification 

at lower temperature

Denitrification as a function of 

temperature

*.10

NO3T2 Lower temperature for 

maximum nitrate 

decay (°C)

Denitrification as a function of 

temperature

20.0 20.0 25.0

NO3K2 Fraction of maximum 

denitrification at 

lower temperature

Denitrification as a function of 

temperature

'.99 '.99 *.99

CO2R Sediment carbondioxide-release rate; 

fraction of sediment 

oxygen demand

Rate at which CO2 is released from 

sediments

.10 .10

PER Iron-release rate from 

bottom sediments

Iron balance; computed as fraction of 

sediment oxygen demand

*.3 - .5 4.0

FES Iron settling 

velocity (m/d)

Paniculate iron-settling velocity under 

anoxic conditions

2.0 .5 - 2.0 2.0

O2NH4 Oxygen stoichiometric 

equivalent for 

ammonia decay

Relates oxygen consumption to 

ammonia decay

*4.57 *4.57 *4.0

O2OM Oxygen stoichiometric

equivalent for organicmatter decay

Relates oxygen consumption to decay 

of organic matter

*1.4 *1.4 *1.5

74 Appendix 2
Appendix 2. Chemical kinetic-rate coefficients and hydraulic and thermal parameters specified as model 

input, Herrington Lake, Kentucky, 1996 Continued

[m, meter; m3 (m/g), cubic meter per meter per gram; --, not applicable; *, dimensionless parameter, m/d, meter per day; 

watts/m2, watts per square meter; °C, degrees Celsius; SOD, streambed oxygen demand; BOD, biological oxygen demand; 

g/m, gram per meter; mg/L, milligram per liter; gO2m /d, grams of oxygen per square meter per day; >, greater than; 

m° 5/s, meter to the half power per second; m2/s, square meter per second]

Parameter 

abbreviation Parameter Computational 

purpose

Value in

Herrington

Lake

model

Values from

1 Cole and

Buchak,

1995

Values from

Giorgino

and Bales,

1997

O2AR Oxygen stoichiometric 

equivalent for dark 

respiration

O2AG Oxygen stoichiometric 

equivalent for algal 

growth

Relates oxygen consumption to algae * 1.4 

dark respiration

Relates oxygen production to algal * 1.4 

growth

*1.4

*1.4

*0.9

*3.0

BIOP Stoichiometric equivalent 

between organic 

matter and phosphorus

BION Stoichiometric equivalent 

between organic 

matter and nitrogen

Relates phosphorus release to decay of *.011 

organic matter

Relates nitrogen release to decay of *.08 

organic matter

*.011

*.08

'.009

*.08

BIOC Stoichiometric equivalent 

between organic 

matter and carbon

Relates carbon release to decay of 

organic matter

'.45 ".45

O2LIM Dissolved-oxygen limit 

(mg/L)

Dissolved-oxygen concentration below 

which anaerobic processes, such as 

nitrification and sediment-nutrient 

releases occur

.2 .10

CEHZY Chezy resistance

coefficient (m°-5/s)

CBHE Coefficient of sedimentwater heat exchange 

(watts/m2/°C)

Represents turbulent exchange of 72 70 

energy at reservoir bottom

Computes heat exchange between 7.0x 10"8 7.0x 10"8 

reservoir bottom and overlying water

70

8x10-

wsc

AX

DX

Wind sheltering 

coefficient

Longitudinal eddy 

viscosity (m2/s)

Longitudinal eddy 

diffusivity (m /s)

Reduces measured wind speed to .85 - .95 0-1.0 .7 - .9 

effective wind speed at water surface

Represents laterally averaged 1.0 1.0 1.0 

longitudinal turbulent transport of 

momentum

Represents laterally averaged 1.0 1.0 1.0 

longitudinal turbulent transport of 

mass and heat

1 Defined appropriate initial start-up value.

Appendix 2 75

Appendix 3. Discharge and nutrient concentrations for selected tributaries entering Herrington Lake, Kentucky, 

October 25, 1995-September 28,1996

[N03 -N, nitrate-nitrogen; NH4-N, ammonia-nitrogen; TP, total phosphorus; SRP, soluble reactive phosphorus; ft3/s, cubic foot per second; 

micrograms per liter, jig/L; for NH4-N, the detection limit is less than 10 jig/L]

Tributary name

Cane Run

Cane Run

Cane Run

Cane Run

Cane Run

Cane Run

Cane Run

Cane Run

Cane Run

Cane Run

Cane Run

Cane Run

Cane Run

Clarks Run

Clarks Run

Clarks Run

Clarks Run

Clarks Run

Clarks Run

Clarks Run

Clarks Run

Clarks Run

Clarks Run

Clarks Run

Clarks Run

Clarks Run

Dix River

Dix River

Dix River

Dix River

Dix River

Station number

03285550

03285550

03285550

03285550

03285550

03285550

03285550

03285550

03285550

03285550

03285550

03285550

03285550

03285200

03285200

03285200

03285200

03285200

03285200

03285200

03285200

03285200

03285200

03285200

03285200

03285200

03285000

03285000

03285000

03285000

03285000

Date

10/25/1995

11/01/1995

11/07/1995

01/16/1996

01/19/1996

02/09/1996

02/28/1996

03/06/1996

04/11/1996

04/24/1996

05/28/1996

07/22/1996

09/28/1996

10/25/1995

11/01/1995

11/07/1995

01/16/1996

01/19/1996

02/09/1996

02/28/1996

03/06/1996

04/11/1996

04/24/1996

05/28/1996

07/22/1996

09/28/1996

10/25/1995

11/01/1995

11/07/1995

01/16/1996

01/19/1996

Discharge 

(ft3/s)

0.3

.6

14.6

20.0

88.3

8.0

19.7

108.0

6.4

35.2

91.0

22.5

155.0

6.5

7.9

90.0

187.0

357.0

35.0

101.0

401.0

27.0

85.0

221.0

64.0

505.0

28.0

76.0

1020.0

1460.0

4,710.0

N03-N 

(H9/L)

1,653.3

1,626.7

3,663.3

3,946.7

5,426.7

5,213.3

4,146.7

4,000.0

4,773.3

4,390.0

5,456.7

6,426.7

2,760.0

12,000.0

9,556.7

3,250.0

3,100.0

3,666.7

5,220.0

3,476.7

2,850.0

6,296.7

3,820.0

4,233.3

7,706.7

2,910.0

1,413.3

935.6

819.7

1,690.0

1,456.7

NH4-N 

(H9/L)

<10.0

<10.0

<10.0

113.3

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

296.0

247.3

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

301.3

<10.0

<10.0

<10.0

<10.0

110.0

<10.0

TP

(H9/L)

361.1

320.8

660.3

311.1

718.8

323.7

393.6

995.9

250.5

473.6

96.9

354.4

1,048

1266.7

1,052.7

854.1

324.1

482.1

316.3

457

755.8

397.1

239.5

375

274.6

982.5

198.8

169.8

109.7

961.6

173

SRP 

(M|/L)

296.6

277.2

501.6

270.3

331.3

258.9

.0

388.6

198.1

166.8

46.9

170.1

767.7

1123.3

991.4

395.6

222.2

282.9

216.2

194.8

586.5

348.4

84.3

305.9

252.7

596.9

142.7

120.0

86.7

109.7

156.6

Appendix 3 77
Appendix 3. Discharge and nutrient concentrations for selected tributaries entering Herrington Lake, Kentucky, 

October 25, 1995-September28, 1996 Continued

[N03-N, nitrate-nitrogen; NH4-N, ammonia-nitrogen; TP, total phosphorus; SRP, soluble reactive phosphorus; ft3/s, cubic foot per second; 

micrograms per liter, u,g/L; for NH4-N, the detection limit is less than 10 u,g/L]

Tributary name

Dix River

Dix River

Dix River

Dix River

Dix River

Dix River

Dix River

Dix River

McKecknie Creek

McKecknie Creek

McKecknie Creek

McKecknie Creek

McKecknie Creek

McKecknie Creek

McKecknie Creek

McKecknie Creek

McKecknie Creek

McKecknie Creek

Mocks Branch

Mocks Branch

Mocks Branch

Mocks Branch

Mocks Branch

Mocks Branch

Mocks Branch

Mocks Branch

Mocks Branch

Mocks Branch

Mocks Branch

Mocks Branch

Mocks Branch

Station number

03285000

03285000

03285000

03285000

03285000

03285000

03285000

03285000

03285400

03285400

03285400

03285400

03285400

03285400

03285400

03285400

03285400

03285400

03285350

03285350

03285350

03285350

03285350

03285350

03285350

03285350

03285350

03285350

03285350

03285350

03285350

Date

02/09/1996

02/28/1996

03/06/1996

04/1 1/1996

04/24/1996

05/28/1996

07/22/1996

09/28/1996

11/07/1995

01/16/1996

01/19/1996

02/28/1996

03/06/1996

04/11/1996

04/24/1996

05/28/1996

07/22/1996

09/28/1996

10/25/1995

11/01/1995

11/07/1995

01/16/1996

01/19/1996

02/09/1996

02/28/1996

03/06/1996

04/11/1996

04/24/1996

05/28/1996

07/22/1996

09/28/1996

Discharge 

(ft3/s)

1,000.0

1,290.0

3,040.0

223.0

1,420.0

5,670.0

1,060.0

4,400.0

1.4

8.6

11.3

1.2

10.4

2.6

1.9

14.3

.7

22.3

.3

.7

34.3

35.7

148.0

12.0

31.9

158.0

7.4

54.6

127.0

52.0

175.0

N03-N

fag/L)

2,236.7

1,830.0

1,765.0

1,416.7

1,506.7

1,920.0

4,106.7

1,193.3

1,666.7

2,250.0

4,240.0

1,833.3

2,100.0

.0

2,260.0

4,420.0

8,013.3

2,416.7

208.7

1,077.0

1,703.3

3,373.3

4,373.3

3,506.7

2,376.7

2,670.0

2,923.3

4,103.3

4,580.0

5,926.7

2,733.3

NH4-N

fag/L)

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

156.3

<10.0

<10.0

<10.0

.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

170.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

TP

(ng/L)

229.8

280.2

1,182

63.7

111.4

0

166.2

1631

1,004

224.6

338.5

646.8

489.7

0

150.2

338.2

279.5

650.6

339.3

262.6

408.3

427.1

733.5

287.2

822.1

1,005.7

167

245.5

244.3

316

1,197.7

SRP

(ng/L)

85.9

207.1

179.0

26.7

12.5

.0

126.5

766.3

670.5

167.9

298.4

126.9

173.6

.0

80.0

40.7

238.8

389.2

240.7

196.3

261.8

216.2

363.8

203.7

278.0

439.6

106.5

12.5

106.7

299.1

610.8

78 Appendix 3
Appendix 4. Average discharge outflows in 1996 at two withdrawal structures at the Dix River Dam

[These data were input into CE-QUAL-W2; --, recording equipment malfunction]

Date

01/01/1996

01/02/1996

01/03/1996

01/04/1996

01/05/1996

01/06/1996

01/07/1996

01/08/1996

01/09/1996

01/10/1996

01/11/1996

01/12/1996

01/13/1996

01/14/1996

01/15/1996

01/16/1996

01/17/1996

01/18/1996

01/19/1996

01/20/1996

01/21/1996

01/22/1996

01/23/1996

01/24/1996

01/25/1996

01/26/1996

01/27/1996

01/28/1996

01/29/1996

01/30/1996

01/31/1996

Discharge 

(gate elevations 

at 532 feet 

above sea 

level)

13.468

13.468

18.529

18.375

10.423

.203

6.398

2.17

9.807

19.299

19.25

19.145

19.04

7.483

1.855

8.463

13.111

13.363

19.404

19.817

20.076

20.489

20.125

19.712

22.344

28.952

29.155

29.211

29.155

29.106

30.191

Discharge 

(gate elevations 

at 584 feet 

above sea 

level)

5.772

5.772

7.941

7.875

4.467

.087

2.742

.93

4.203

8.271

8.25

8.205

8.16

3.207

.795

3.627

5.619

5.726

8.316

8.493

8.604

8.781

8.625

8.448

9.576

12.408

12.495

12.519

12.495

12.474

12.939

Date

02/01/1996

02/02/1996

02/03/1996

02/04/1996

02/05/1996

02/06/1996

02/07/1996

02/08/1996

02/09/1996

02/10/1996

02/11/1996

02/12/1996

02/13/1996

02/14/1996

02/15/1996

02/16/1996

02/17/1996

02/18/1996

02/19/1996

02/20/1996

02/21/1996

02/22/1996

02/23/1996

02/24/1996

02/25/1996

02/26/1996

02/27/1996

02/28/1996

02/29/1996

03/01/1996

03/02/1996

Discharge 

(gate elevations 

at 532 feet 

above sea 

level)

27.405

30.135

30.191

29.932

29.624

29.624

29.155

28.952

28.742

28.28

8.26

19.145

28.231

28.434

28.385

27.916

2.324

1.19

8.099

8.568

2.268

6.244

8.463

10.22

--

7.175

11.095

20.335

25.802

.616

_.

Discharge 

(gate elevations 

at 584 feet 

above sea 

level)

11.745

12.915

12.939

12.828

12.696

12.696

12.495

12.408

12.318

12.12

3.54

8.205

12.099

12.186

12.165

11.964

.996

.51

3.471

3.672

.972

2.676

3.627

4.38

--

3.075

4.755

8.715

11.058

.264

_

Appendix 4 79
Appendix 4. Average discharge outflows in 1996 at two withdrawal structures at the Dix River Dam Continued

[These data were input into CE-QUAL-W2; , recording equipment malfunction]

Date

03/03/1996

03/04/1996

03/05/1996

03/06/1996

03/07/1996

03/08/1996

03/09/1996

03/10/1996

03/11/1996

03/12/1996

03/13/1996

03/14/1996

03/15/1996

03/16/1996

03/17/1996

03/18/1996

03/19/1996

03/20/1996

03/21/1996

03/22/1996

03/23/1996

03/24/1996

03/25/1996

03/26/1996

03/27/1996

03/28/1996

03/29/1996

03/30/1996

03/31/1996

04/01/1996

04/02/1996

04/03/1996

Discharge 

(gate elevations 

at 532 feet

above sea

level)

3.304

20.279

12.593

19.922

28.588

27.972

27.818

28.077

28.28

28.231

28.077

27.916

27.762

27.559

27.503

27.349

27.195

27.146

27.195

27.195

20.594

--

19.971

27.349

14.35

18.319

14.504

--

--

17.031

9.548

7.175

Discharge 

(gate elevations 

at 584 feet

above sea

level)

1.416

8.691

5.397

8.538

12.252

11.988

11.922

12.033

12.12

12.099

12.033

11.964

11.898

11.811

11.787

11.721

11.655

11.634

11.655

11.655

8.826

--

8.559

11.721

6.15

7.851

6.216

--

--

7.299

4.092

3.075

Date

04/04/1996

04/05/1996

04/06/1996

04/07/1996

04/08/1996

04/09/1996

04/10/1996

04/11/1996

04/12/1996

04/13/1996

04/14/1996

04/15/1996

04/16/1996

04/17/1996

04/18/1996

04/19/1996

04/20/1996

04/21/1996

04/22/1996

04/23/1996

04/24/1996

04/25/1996

04/26/1996

04/27/1996

04/28/1996

04/29/1996

04/30/1996

05/01/1996

05/02/1996

05/03/1996

05/04/1996

05/05/1996

Discharge 

(gate elevations 

at 532 feet

above sea

level)

3.766

17.647

4.389

4.13

7.28

21.777

7.532

3.409

-

--

.

2.373

7.532

.105

-

--

-

--

20.797

26.992

12.95

7.791

20.384

10.066

--

8.309

-

21.315

13.573

19.817

--

Discharge 

(gate elevations 

at 584 feet

above sea

level)

1.614

7.563

1.881

1.77

3.12

9.333

3.228

1.461

--

-

-

1.017

3.228

.045

-

-

--

--

8.913

11.568

5.55

3.339

8.736

4.314

-

3.561

--

9.135

5.817

8.493

~

80 Appendix 4
Appendix 4. Average discharge outflows in 1996 at two withdrawal structures at the Dix River Dam Continued 

[These data were input into CE-QUAL-W2; --, recording equipment malfunction]

Date

05/06/1996

05/07/1996

05/08/1996

05/09/1996

05/10/1996

05/11/1996

05/12/1996

05/13/1996

05/14/1996

05/15/1996

05/16/1996

05/17/1996

05/18/1996

05/19/1996

05/20/1996

05/21/1996

05/22/1996

05/23/1996

05/24/1996

05/25/1996

05/26/1996

05/27/1996

05/28/1996

05/29/1996

05/30/1996

05/31/1996

06/01/1996

06/02/1996

06/03/1996

06/04/1996

06/05/1996

06/06/1996

Discharge 

(gate elevations 

at 532 feet 

above sea 

level)

11.718

10.164

21.105

28.952

11.305

-

--

-

--

--

--

13.986

19.349

22.562

18.72

6.12

9.027

.882

.558

.12

.2

-

.01

.023

1.665

2.361

9.75

10.487

10.984

12.285

28.123

40.251

Discharge 

(gate elevations 

at 584 feet 

above sea 

level)

5.022

4.356

9.045

12.408

4.845

--

--

-

-

-

-

5.994

3.015

3.377

2

1.08

1.146

.706

.382

.02

.1

.005

.094

.198

.257

.231

.292

.18

.168

5.265

2.411

2.433

Date

06/07/1996

06/08/1996

06/09/1996

06/10/1996

06/11/1996

06/12/1996

06/13/1996

06/14/1996

06/15/1996

06/16/1996

06/17/1996

06/18/1996

06/19/1996

06/20/1996

06/21/1996

06/22/1996

06/23/1996

06/24/1996

06/25/1996

06/26/1996

06/27/1996

06/28/1996

06/29/1996

06/30/1996

07/01/1996

07/02/1996

07/03/1996

07/04/1996

07/05/1996

07/06/1996

07/07/1996

07/08/1996

Discharge 

(gate elevations 

at 532 feet 

above sea 

level)

38.279

14.528

15.312

14.385

13.279

31.059

21.007

37.145

35.715

33.088

28.703

20.069

35.801

27.619

18.368

--

6.762

6.293

--

10.066

-

8.673

7.329

-

.875

-

--

--

--

--

--

Discharge 

(gate elevations 

at 584 feet 

above sea 

level)

1.823

1.648

1.458

1.269

1.067

1.513

9.003

8.683

8.018

7.272

6.512

3.823

3.58

2.367

1.574

-

2.898

2.697

-

4.314

-

3.717

3.141

-

.375

-

-

--

-

~

--

__

Appendix 4 81
Appendix 4. Average discharge outflows in 1996 at two withdrawal structures at the Dix River Dam Continued 

[These data were input into CE-QUAL-W2; --, recording equipment malfunction]

Date

07/09/1996

07/10/1996

07/11/1996

07/12/19%

07/13/1996

07/14/1996

07/15/1996

07/16/1996

07/17/1996

07/18/1996

07/19/1996

07/20/1996

07/21/1996

07/22/1996

07/23/1996

07/24/1996

07/25/1996

07/26/1996

07/27/19%

07/28/1996

07/29/1996

07/30/1996

07/31/1996

08/01/1996

08/02/1996

08/03/1996

08/04/1996

08/05/1996

08/06/1996

08/07/1996

08/08/1996

08/09/1996

Discharge 

(gate elevations 

at 532 feet

above sea

level)

--

--

--

--

-

--

9.527

7.16

15.942

27.404

162.562

610.566

262.303

1.56

1.114

18.788

26.608

24.334

27.609

26.292

22.164

11.605

20.116

27.823

20.692

51.897

47.33

53.684

30.273

23.533

11.9

.033

Discharge 

(gate elevations 

at 584 feet

above sea

level)

--

--

-

--

-

--

4.083

2.166

3.854

5.593

.57

62.489

43.717

.134

2.387

8.052

7.653

6.999

6.317

5.672

5.028

2.124

2.73

3.112

8.868

4.236

3.864

3.486

3.177

2.831

1.641

.012

Date

08/10/1996

08/11/1996

08/12/1996

08/13/1996

08/14/1996

08/15/1996

08/16/1996

08/17/19%

08/18/1996

08/19/1996

08/20/1996

08/21/1996

08/22/1996

08/23/1996

08/24/1996

08/25/1996

08/26/1996

08/27/1996

08/28/1996

08/29/1996

08/30/1996

08/31/1996

09/01/1996

09/02/1996

09/03/1996

09/04/1996

09/05/1996

09/06/1996

09/07/1996

09/08/1996

09/09/1996

09/10/1996

Discharge 

(gate elevations 

at 532 feet

above sea

level)

0.045

.05

.143

.137

24.08

12.887

30.188

.111

.104

26.372

10.164

7.532

12.334

9.289

-

-

--

--

5.782

7.637

--

-

-

--

--

7.378

8.827

10.528

6.916

7.378

10.423

12.95

Discharge 

(gate elevations 

at 584 feet

above sea

level)

0.01

.05

.072

.066

4.885

2.699

5.308

.042

.036

3.478

4.356

3.228

5.286

3.981

~

..

--

..

2.478

3.273

«

~

-

..

..

3.162

3.783

4.512

2.964

3.162

4.467

5.55

82 Appendix 4
Appendix 4. Average discharge outflows in 1996 at two withdrawal structures at the Dix River Dam Continued

[These data were input into CE-QUAL-W2; --, recording equipment malfunction]

Date

09/11/1996

09/12/1996

09/13/1996

09/14/1996

09/15/1996

09/16/1996

09/17/1996

09/18/1996

09/19/1996

09/20/1996

09/21/1996

09/22/1996

09/23/1996

09/24/1996

09/25/1996

09/26/1996

09/27/1996

09/28/1996

09/29/1996

09/30/1996

10/01/1996

10/02/1996

10/03/1996

10/04/1996

10/05/1996

10/06/1996

10/07/1996

10/08/1996

10/09/1996

10/10/1996

10/11/1996

10/12/1996

Discharge 

(gate elevations 

at 532 feet

above sea

level)

7.483

15.582

17.388

19.558

18.627

19.404

17.962

18.683

18.165

17.444

16.408

-

17.857

17.962

--

4.9

3.507

16.359

28.952

28.798

24.773

19.04

17.234

17.962

7.483

--

11.97

12.334

9.751

--

-

_

Discharge 

(gate elevations 

at 584 feet

above sea

level)

3.207

6.678

7.452

8.382

7.983

8.316

7.698

8.007

7.785

7.476

7.032

-

7.653

7.698

-

2.1

1.503

7.011

12.408

12.342

10.617

8.16

7.386

7.698

3.207

--

5.13

5.286

4.179

--

--

_

Date

10/13/1996

10/14/1996

10/15/1996

10/16/1996

10/17/1996

10/18/1996

10/19/1996

10/20/1996

10/21/1996

10/22/1996

10/23/1996

10/24/1996

10/25/1996

10/26/1996

10/27/1996

10/28/1996

10/29/1996

10/30/1996

10/31/1996

11/01/1996

11/02/1996

11/03/1996

11/04/1996

11/05/1996

11/06/1996

11/07/1996

1 1/08/1996

11/09/1996

11/10/1996

11/11/1996

11/12/1996

11/13/1996

Discharge 

(gate elevations 

at 532 feet

above sea

level)

--

--

8.512

7.637

--

--

--

--

-

--

-

--

5.215

--

--

--

--

--

--

11.718

18.375

18.375

16.772

6.706

--

5.215

--

--

--

--

--

_

Discharge 

(gate elevations 

at 584 feet

above sea

level)

--

-

3.648

3.273

--

--

--

-

--

--

--

--

2.235

--

--

--

-

--

5.022

7.875

7.875

7.188

2.874

-

2.235

--

--

-

--

--

Appendix 4 83
Appendix 4. Average discharge outflows in 1996 at two withdrawal structures at the Dix River Dam Continued

[These data were input into CE-QUAL-W2; --, recording equipment malfunction]

Date

11/14/1996

11/15/1996

11/16/1996

11/17/1996

11/18/1996

11/19/1996

11/20/19%

11/21/19%

11/22/1996

11/23/1996

11/24/1996

1 1/25/1996

1 1/26/1996

1 1/27/19%

1 1/28/1996

11/29/1996

1 1/30/1996

12/01/1996

12/02/1996

12/03/1996

12/04/1996

12/05/1996

12/06/19%

12/07/1996

Discharge 

(gate elevations 

at 532 feet

above sea

level)

--

--

-

--

--

--

--

--

--

-

--

--

--

--

-

--

--

28.49

28.693

28.539

28.798

28.952

27.454

18.578

Discharge 

(gate elevations 

at 584 feet

above sea

level)

--

--

--

-

--

--

--

-

-

--

-

--

--

--

-

-

-

12.21

12.297

12.231

12.342

12.408

11.766

7.%2

Date

12/08/1996

12/09/1996

12/10/1996

12/11/1996

12/12/1996

12/13/19%

12/14/19%

12/15/1996

12/16/1996

12/17/1996

12/18/19%

12/19/1996

12/20/1996

12/21/1996

12/22/19%

12/23/1996

12/24/1996

12/25/1996

12/26/1996

12/27/1996

12/28/1996

12/29/1996

12/30/1996

12/31/1996

Discharge 

(gate elevations 

at 532 feet

above sea

level)

--

18.27

--

18.116

18.473

18.837

17.493

-

13.265

20.748

29.211

29.316

29.155

29.001

26.628

19.509

20.02

29.155

24.773

20.076

20.02

19.922

22.603

16.618

Discharge 

(gate elevations 

at 584 feet

above sea

level)

-

7.83

--

7.764

7.917

8.073

7.497

- ~

5.685

8.892

12.519

12.564

12.495

12.429

11.412

8.361

8.58

12.495

10.617

8.604

8.58

8.538

9.687

7.122

84 Appendix 4 &U.S. GOVERNMENT PRINTING OFFICE: WOO 551-777/39013