GEOLOGICAL SURVEY CIRCULAR 811 

Summary of the River-Quality Assessment 

of the Upper Chattahoochee 

River Basin, Georgia 

Summary of the River-Quality Assessment 

of the Upper Chattahoochee 

River Basin, Georgia 

By R. N. Cherry, R. E. Faye, J. K. Stamer, and R. L. Kleckner 

G E 0 l 0 G I CAl SURVEY CIRCUlAR 811 

1980 
United States Department of the Interior 

CECIL D. ANDRUS, Secretary 

Geological Survey 

H. William Menard, Director 

Library of Congress Cataloging in Publication DATA 

Summary of the river-quality assessment of the Upper Chattahoochee River Basin, Georgia 

Circular- Geological Survey 811 

Bibliography: p. 4 7 

Supt. of Docs. No.: I 19 4/2: 811 

1. Water quality-Georgia. 2. Water quality--Chattahoochee River watershed. 

I. Cherry, Rodney N., 1928- II. Series: United States. Geological 

Survey Circular 811. 

QE75.C5 no. 811 (TD224.G4) 557.3s (628.1'6867582) 80-607082 

Free on application to Branch of Distribution, U.S. Geological Survey 

604 South Pickett Street, Alexandria, VA 22304 
CONTENTS 

Page 

Abstract ___ __ __ __ __ _ _ _ _ __ ____ _ _________ ___ ___ _______ 1 

Introduction ---------------------------------------- 1 

Objectives and scope ---------------------------- 1 

Acknowledgments _______ _____________ __________ 2 

Description of the Upper Chattahoochee River Basin __ 2 

llydrology -------------------------------------- 2 

Land use________________________________________ 2 

VVater use -------------------------------------- 4 

Nature of the problem ------------------------------ 6 

Erosion and sediment transport ______________________ 7 

Flow and temperature models________________________ 9 

Point and nonpoint discharges________________________ 10 

Point discharges -------------------------------- 11 

Nonpoint discharges ---------------------------- 11 

Relation of nonpoint constituent yields to urbanization ------------------------------------------ 11 

Average annual urban, rural, and forested non point 

discharges to the Upper Chattahoochee River____ 16 

Comparison of magnitude of point and nonpoint discharges to the Upper Chattahoochee River ______ 17 

Present and future effects of point and nonpoint discharges on the dissolved-oxygen regime of the 

Upper Chattahoochee River____________________ 17 

Page 

Point and nonpoint discharges-Continued 

Economic considerations of wastewater management 

alternatives _ __ _ _ ____ _ ___________ __ __ ____ _ _ _ _ _ 24 

Cost of wastewater treatment -------------------- 26 

Cost of changing release pattern from Buford Dam 26 

Cost of reregulation of Chattahoochee River flows__ 31 

Cost of wastewater management alternatives______ 31 

Biological assessment________________________________ 32 

Nitrification ___ __ _ _ _____ _ ____ __ _ ___ _________ _ _ _ _ 32 

Phytoplankton ------------------------------- ___ 35 

Algal growth potential __________________________ 38 

Relation of algal growth potential to nutrients in 

VVest Point Lake ------------------------------ 39 

Relation of phytoplankton growth to algal growth 

potential in West Point Lake __________________ 39 

Present and future effects of point and non point discharges on algal growth in VV est Point Lake _ _ _ _ 41 

Summary _ ______ __ _______ _ _________________ _ ___ _ ___ 44 

Selected references _ _ _ ______________ ______ _ _ __ _ __ _ __ _ 4 7 

ILLUSTRATIONS 

Page 

FIGURE 1. Map showing Upper Chattahoochee River Basin, Georgia -------------------------------------------- 3 

2-7. Graphs showing: 

2. Mean daily discharge of the Chattahoochee River at the Atlanta station for 1969-77 __________ 4 

3. Flow duration of the Chattahoochee River at the Atlanta gage before and after construction of 

Buford Dam -------------------------------------------------------------------------- 5 

4. DO concentrations at the Fairburn station monitor and mean daily discharge at the Atlanta station 

during July 1977---------------------------------------------------------------------- 8 

5. Observed and computed stages of the Chattahoochee River at Atlanta, at the City of Atlanta VVater 

VVorks, at the Plant McDonough outfall, near Fairburn, and near VVhitesburg ____________ 13 

6. Observed and computed temperatures of the Chattahoochee River at Atlanta, at the plant 

McDonough intake, at Georgia llighway 280, near Fairburn, and near VVhitesburg ________ 14 

7. Relationship of average annual yields of dissolved solids and BODu to percentage of urbanization 16 

8. Diagrams showing magnitude and nature of average annual point (crosshatched) and nonpoint (clear) loads 

for selected constituents at stations on the Chattahoochee River at Atlanta, Fairburn, and VVhitesburg 18 

9. Diagrams showing magnitude and nature of point (crosshatched) and nonpoint (clear) loads for selected 

constituents at stations on the Chattahoochee River at Atlanta, Fairburn, and VVhitesburg during the 

storm period, March 12-15, 1976 -------------------------------------------------------------- 19 

10-36. Graphs showing: 

10. Mean daily DO concentrations at the Chattahoochee River near Fairburn station monitor, October 

1976 to September 1977 ________________________________________________________________ 20 

11. Magnitude of point- and nonpoint-source BOD, ammonium nitrogen, and nitrate nitrogen loads in 

the Atlanta-to-Franklin reach of the river during low-flow period June 1-2, 1977 __________ 22 

III 
FIGURES 10-36.-Graphs showing-Continued Page 

12. Comparison of observed and computed BODu concentrations in the Atlanta-to-Franklin reach of 

the river during low-flow period, June 1-2, 1977 ---------------------------------------- 23 

13. Comparison of observed and computed ammonium nitrogen concentrations in the Atlanta-toFranklin reach of the river during low-flow period, June 1-2, 1977------------------------ 24 

14. Comparison of observed and computed nitrate nitrogen concentrations in the Atlanta-to-Franklin 

reach of the river during low-flow period, June 1-2, 1977---------------------------------- 25 

15. Comparison of observed and computed DO concentrat~ons in the Atianta-to-Franklin reach of the 

river during low-flow period, June 1-2, 1977 -------------------------------------------- 26 

16. DO concentrations observed and DO concentration profile due only to carbonaceous oxygen demands in the Atlanta-to-Franklin reach of the river during low-flow period, June 1-2, 1977 27 

17. DO concentrations observed and DO concentration profile due only to nitrogenous oxygen demands 

in the Atlanta-to-Franklin reach of the river during low-flow period, June 1-2, 1977 ------ 28 

18. Temperature of river water in the Atlanta-to-Franklin reach of the river during low-flow period, 

June 1-2, 1977 ______________________ - __________ --------------------------------------- 29 

19. Comparison of observed and computed DO concentrations in the Atlanta-to-Franklin reach of the 

river during low-flow period, August 31 to September 9, 1976 ---------------------------- 29 

20. Relationship of minimum DO concentration to streamflow at Atlanta station and percentage of 

total wastewater discharge nitrified for years 1980, 1990, and 2000 ---------------------- 30 

21. Relationship of annual cost of converting from secondary treatment to nitrification to percentage of 

total waste discharge nitrified for years 1980, 1990, and 2000 ---------------------------- 31 

22. Relationship of average annual benefits foregone at Buford Dam to streamflow at Atlanta station 

for years 1980, 1990, and 2000 -------------------------------------------------------- 31 

23. Comparison of decreases in DO resulting from nitrification to total decrease in DO in the Atlantato-Franklin reach during low-flow period, June 1-2, 1977 -------------------------------- 33 

24. Nitrobacter population in Chattahoochee River water and benthic sediment during June 1-2, 1977 34 

25. Nitrosomonas population in Chattahoochee River water and benthic sediment during June 1-2, 

1977---------------------------------------------------------------------------------- 34 

26. Mean concentrations of ammonium, nitrite, and nitrate as nitrogen in the Chattahoochee River 

during June 1-2, 1977 ---------------------------------------------------------------- 35 

27. Concentration of phytoplankton by river mile for August 1976-------------------------------- 36 

28. Average concentration of blue-green algae by month in Lake Sidney Lanier and West Point Lake 37 

29. Average concentration of green algae by month in Lake Sidney Lanier and West Point Lake -- 37 

30. Average concentration of diatoms by month in Lake Sidney Lanier and West Point Lake ------ 38 

31. Mean annual concentrations of total phytoplankton, dissolved orthophosphate, and nitrite plus 

nitrate by river mile ------------------------------------------------------------------ 39 

32. Mean annual concentrations of AGP, dissolved orthophosphate, and nitrite plus nitrate by river 

mile ---------------------------------------------------------------------------------- 40 

33. Observed AGP by river mile downstream from Franklin station ------------------------------ 41 

34. Observed phytoplankton concentrations by river mile downstream from Franklin station ______ 42 

35. AGP at Franklin versus algal growth potential at Whitesburg-------------------------------- 43 

36. Relationship of dissolved orthophosphate and dissolved nitrate concentrations to water dicharge in 

the Chattahoochee River near Whitesburg ---------------------------------------------- 44 

TABLES 

Page 

TABLE 1. Land use in the Upper Chattahoochee River Basin -------------------------------------------------- 2 

2. Estimated !'lverage water use and generating capacity of electric-generating facilities in the Upper Chattahoochee River Basin ------------------------------------------------------------------------ 4 

3. Estimated water-supply withdrawals from the Upper Chattahoochee River for the years 1976 and 2000 __ 6 

4. Mean daily treated wastewater returns for 1976 and estimated returns for the year 2000 to the Chattahoochee River and its tributaries for wastewater treatment facilities in the study area __________ 6 

5. Mean monthly air temperature and number of days and hours per month during 1977 in which the DO 

concentration was less than 5.0 mg/L at the Chattahoochee River near Fairburn monitor __________ 7 

6. Summary of regression data relating suspended constituent and suspended silt plus clay concentrations__ 10 

7. Summary of average annual suspended and total constituent discharges ------------------------------ 12 

8. Annual yields of suspended constituents from representative land-use watersheds______________________ 13 

9. Magnitude and nature of point discharges for selected constituents for the year 1976 __________________ 15 

IV 
TABLE 10. 

11. 

12. 

13. 

14. 

15. 

16. 

Page 

Average annual yields and average daily concentrations for selected constituents for urban, rural, and 

forested nonpoint discharges ------------------------------------------------------------------ 15 

Comparison of average annual nonpoint constituent loads computed from urban, rural, and forested yields 

to nonpoint constituent loads computed from river measurements -------------------------------- 17 

Constituent loads at the Atlanta, Fairburn, Whitesburg, and Franklin stations, constituent loads from 

point discharges, and resulting constituent concentrations at Franklin, June 1-2, 1977 ____________ 20 

Chemical, physical, and flow data used to compute DO profiles in the Atlanta-to-Franklin reach of the river 

for the years 1977 and 2000-------------------------------------------------------------------- 21 

Average daily flow of waste treatment plants discharging to the Chattahoochee River between Atlanta and 

Whitesburg, and the annualized cost of converting the plants from secondary to advanced levels of 

treatment (nitrification)________________________________________________________________________ 27 

Summary of economic considerations of wastewater management alternatives for the years 1980, 1990, and 

2000 ------------------------------------------------------------------------------------------ 32 

Summary of present (1977l and future (year 2000) effects of point and nonpoint phosphorus and nitrogen 

discharges on phytoplankton concentrations in West Point Lake---------------------------------- 45 

CONVERSION FACTORS 

[For use of those readers who may prefer to use metric units rather than inch-pound units, the conversion factors for the terms used in this report are listed below] 

Multiply U.S. customary unit 

ft (foot) 

ff1/s (cubic foot per second) 

in (inch) 

mi (mile) 

mF (square mile) 

By 

3.048x w-l 

2.832x 10-2 

2.540 

2.540x 10- 1 

1.609 

2.590 

v 

To obtain metric unit 

m (meter) 

ma/s (cubic meter per second) 

em (centimeter) 

mm (millimeter) 

km (kilometer) 

km2 (square kilometer) 

Summary of the River-Quality Assessment of the 

Upper Chattahoochee River Basin, Georgia 

By R. N. Cherry, R. E. Fay, J. K. Stamer, and R. L. Kleckner 

ABSTRACT 

The river-quality assessment of the Upper Chattahoochee 

River Basin included studies of (1) the impact of heat loads on 

river quality, (2) sediment transport and deposition, (3) magnitude and nature of point and nonpoint discharges, and (4) 

phytoplankton growth in the river and reservoirs. 

The combined thermal effects of flow regulation and powerplants effluents resulted in mean daily river temperature 

downstream of the powerplants about equal to or less than 

computed natural temperatures. The average annual river 

temperature in 1976 was 14.0° Celsius just upstream of the 

Atkinson-McDonough thermoelectric powerplants and 16.0° 

Celsius just downstream from the powerplants. During a 

low-flow period in June 1977 the heat load from the two powerplants caused an increase in river temperatures of about 7° 

Celsius and a subsequent decrease in the dissolved-oxygen 

concentration of about 0.2 milligrams per liter. During the 

June low-flow period, point sources contributed 63 percent of 

the ultimate biochemical oxygen demand and 97 percent of 

ammonium as nitrogen at the Franklin station. Oxidation of 

ultimate biochemical demand and ammonium caused 

dissolved-oxygen concentrations to decrease from about 8.0 

milligrams per liter at river mile 299 to about 4.5 milligrams 

per liter at river mile 271. Dissolved orthophosphate is the 

nutrient presently limiting phytoplankton growth in the West 

Point Lake when water temperatures are greater than about 

26° Celsius. 

INTRODUCTION 

In 1972, the U.S. Geological Survey began a 

program of river-quality assessments. The 

objectives were (1) to define the character, interrelationships, and apparent causes of existing 

river-quality conditions and (2) to devise and 

demonstrate analytical approaches and the tools 

and methodology needed for developing waterquality information that would provide a sound 

technical basis for planners and managers to use 

in assessing river-quality problems and evaluating management alternatives. The river-quality 

1 

assessment program involves seven steps: (1) 

identifying the significant problems of major 

importance in the basin; (2) analyzing the hydrology; (3) deciding upon assessment methods appropriate to each problem; (4) collecting data relevant to each problem by intensive investigation 

and synoptic surveys; (5) analyzing the data for 

cause-effect relationship, formulating and calibrating predictive methods by which changes in 

river-quality parameters can be projected, and 

verifying the predicted results against observed 

conditions; (6) forecasting the impacts in river 

quality of various planning alternatives; and (7) 

presenting the results of river-quality assessments in a manner understandable to planners 

and decisionmakers. 

The 3-year river-quality assessment of the 

Upper Chattahoochee River Basin, Georgia, 

began April1, 1975. The purpose ofthe study was 

to demonstrate the types of information that can 

be provided to guide meaningful management 

decisions regarding alternatives for basic development and future needs of the Upper Chattahoochee in which maintenance and improvement 

of water quality are requisite. 

OBJECTIVES AND SCOPE 

The objectives and scope of the study included 

(1) the development of flow and temperature 

models to evaluate the impact of heat loads from 

thermoelectric plants on stream temperature, (2) 

a qualitative and quantitative definition of sediment transport and deposition, (3) an assessment 

of the magnitudes and nature of point and nonpoint discharges to selected reaches of the river, 

and their effect on the DO (dissolved oxygen) regime of the river, (4) economic considerations of 
maintaining desired minimum concentrations of 

DO in the Atlanta to Franklin reach of the river, 

and (5) use of microbiological determinations to 

develop quantitative methods to estimate algae 

concentrations in West Point Lake. 

ACKNOWLEDGMENTS 

The authors acknowledge the Cobb, DeKalb, 

and Fulton County governments and the City of 

Atlanta for their assistance in the collection of 

data. Special thanks go to the forecasters of the 

National Weather Service at Atlanta and to 

Johnny Beckman ofWSB-TV, who have provided 

timely weather information before and during the 

point and nonpoint data-collection efforts. Special 

thanks also go to the Georgia Power Company, 

and in particular to A. W. Elkins, for their efforts 

in maintaining steady low-flow conditions in the 

river during the DO data-collection studies. The 

authors also thank the Environmental Protection 

Division of the Georgia Department of Nat ural 

Resources, South Atlantic Division of the U.S. 

Army Corps of Engineers, Region IV of the U.S. 

Environmental Protection Agency, Atlanta Regional Commission, and members of the Ad Hoc 

Working Group on River Quality Assessment of 

the Advisory Committee on Water Data for Public 

Use for their critical review of manuscripts and . 

many helpful suggestions relative to the types of 

data and methods of analyses which would be 

most useful in managing the Upper Chattahoochee River. 

DESCRIPTION OF THE UPPER 

CHATTAHOOCHEE RIVER BASIN 

The Upper Chattahoochee River (fig. 1) begins 

on the southern slopes of the Blue Ridge Mountains in northeast Georgia and flows generally 

southwestward through the metropolitan Atlanta 

area to the Georgia-Alabama State line. The 

drainage area of the Upper Chattahoochee River 

is 3,440 mi2 (square miles) (table 1). Land-surface 

altitudes range from about 4,000 ft above mean 

sea level in the headwaters to about 635 ft above 

mean sea level at West Point Lake. 

Rainfall in the basin averages about 54 inches 

per year and is greatest in the upland areas and 

in the southernmost part of the basin. Annual air 

2 

TABLE 1.-Land use, in square miles, in the Upper 

Chattahoochee River Basin 

Basin upstream of- Urban 

Buford Dam ______________ 37 

Atlanta __________________ 129 

Fairburn ________________ 372 

Whitesburg ______________ 396 

West Point Dam _______ _433 

Rural Forest 

165 838 

239 1,082 

310 1,378 

372 1,662 

546 2,461 

Drainage area 

1,040 

1,450 

2,060 

2,430 

3,440 

temperature averages about 16°C (degrees Celsius), with colder temperatures occurring in the 

mountains and warmer temperatures in the 

southernmost part of the basin. 

HYDROLOGY 

The flow of the Chattahoochee River in the 

study reach is dependent on rainfall and operation of hydroelectric-generating facilities. The 

highest flows generally occur in the spring of the 

year, and the lowest flows occur in late autumn. 

The average flow at Buford Dam, based on 35 

years of record, is 2,168 ft3/s (cubic feet per second), and at Atlanta, which is about midway in 

the study reach, the average daily flow based on 

43 years of record is 2,603 ft3/s. A maximum flow 

of 59,000 ft 3/s occurred at Atlanta in 1946, and a 

minimum daily flow of 296 ft3/s occurred in 1957. 

Average daily flow at the Atlanta station for the 

period 1969-77 is show in figure 2. 

Flow regulation in the midriver reaches has occurred for many years because of operation of 

hydroelectric-generating facilities. The most pronounced changes in regulated flow have occurred 

since the construction and operation of Buford 

Dam. Figure 3 shows the flow duration of the 

Chattahoochee River at the Atlanta station before and after regulation by Buford Dam. The frequency of both the higher and lower flows has 

decreased. 

Buford Dam generally does not produce peak 

hydroelctric power on weekends. Estimated 

weekend flow at the Atlanta station is about 

1,200 ft3/s. 

LAND USE 

Land in the Upper Chattahoochee River Basin 

is predominately forest (table 1). Upstream of 

Buford Dam, about 80 percent of the land is 

forested and 16 percent agricultural. Agricultural 
~ ~ 

35°r---------------~------------------------------------~---------------------------, 

EXPLANATION 

RM River mOe 

--··--··-··- Basin boundary 

A. Water-quality-data collection site 

o City 

I 

\ •-----+--~\-. - RM 235.46 (FRANKLIN) 

( 

< 

J WEST POINT....._ __ ~ .. 

RESERVOIR 

0 WEST POINT 

0 

I 

0 

./ 

( 

( 

') 

~ 

/··--. 

("-""-.""" '""'--'" 

_,/ lA.-~~RM 348.32 (BUFORD DAM) 

10 

I 

I 

10 

20 

I 

30 

I 

I 

20 

40 

I 

50 Kl LOMETERS 

I 

I 

30 MILES 

FIGURE 1.-Upper ChattahOochee River Basin, Georgia. 

3 
6000 

5000 

0 

z 

0 

u 

w 4000 

en 

a: 

w 

c.. 

I- 3000 w 

w 

u.. 

u 

iii 

:::::> 

u 2000 

~ 

ui 

(!) 

a: 

<( 

::I: 

u 

en 

0 

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

FIGURE 2.-Mean daily discharge of the Chattahoochee River at the Atlanta station for 1969--77. 

activities are concentrated in the stream valleys 

and on the lower slopes. Crop and pastureland 

occupy a significant part of the agricultural land. 

Poultry operations, primarily broiler production, 

are a dominant agricultural activity. Gainesville 

is the largest urban complex in this part of the 

basin. 

In the reach from Buford Dam to Atlanta, about 

59 percent of the land is forested, 22 percent is 

urbanized, and 18 percent is farmed. About 40 

percent of the agricultural land is in cropland and 

pasture. Corn and soybeans are the dominant 

crops. 

The basin from Atlanta to West Point Dam includes most of Metropolitan Atlanta, the major 

urban complex in the basin. Land in the Atlanta 

area is predominantly residential, but commercial and industrial activities are significant. Some 

of the more important industrial activities include automobile assembly, food processing, and 

light manufacturing. Downstream from Atlanta, 

forest land is predominant. Agricultural use of 

the land is about the same as in the Buford Damto-Atlanta reach, and the types of agricultural 

operations are similar. 

WATER USE 

The water of the Chattahoochee River is 

utilized extensively for power generation, water 

4 

supply, water-quality maintenance, and recreation. 

Five electric power-generating facilities are located on the mainstem of the river and have a 

combined generating capacity of about 3.8 million 

kilowatts. Buford and Morgan Falls Dams are 

peak-power hydroelectric-generating facilities, 

and the Atkinson-McDonough, Yates, and 

Wansley Plants are base load fossil-fuel 

thermoelectric-generating facilities. Morgan 

Falls is a run-of-the-river plant, utilizing 

hydropower-released waters from Buford Dam. 

The estimated average water use and generating 

capacity of the plants are shown in table 2. 

TABLE 2.-Estimated average water use and generating ca- pacity of electric-generating facilities in the Upper Chattahoochee River Basin 

[From Georgia Power Co.] 

Capacity Average water 

River mile Name of facility (kwl use (ft3 /s) 

Hydroelectric facilities 

348.32 Buford Dam-------------~------ 86,000 2,200 

312.62 Morgan Falls Dam______________ 16,800 2,500 

299.11 

259.70 

249.20 

Thermoelectric facilities 

Plants Atkinson-McDonough ____ 730,000 909 

Plant Yates ____________________ 1,250,000 1,030 

Plant Wansley ________________ 1,760,000 '73 

'One small unit on line in 1976. 
c 

z 

0 

u 

w 

C/) 24,000 

a: 

w 

a.. 

tu 

w 

u. 

u 

iii 20,000 :::> 

u 

~ 

~ ..J 

u. 

~ 16,000 

~ 

~ C/) 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

v192!Hi6 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

1965-76 

0 0.1 1 5 20 50 90 99 99.99 

PERCENTAGE OF TIME FLOW EQUALED OR EXCEEDED THE VALUE INDICATED 

FIGURE 3.-Flow duration of the Chattahoochee River at the Atlanta gage before and after construction of Buford Dam. 

At the present time (1978) public water-supply 

withdrawals from the Upper Chattahoochee 

River average about 280 ft3/s, of which about 173 

5 

ft 3/s is withdrawn in the reach from Morgan Falls 

to Fairburn. Other public water supplies are 

withdrawn from Lake Sidney Lanier and West 
Point Lake. Table 3 lists the major water users in 

-ihe basin and shows the estim~ted 1976 and 2000 

water-supply withdrawals. 

Large amounts of wastewater are discharged 

(table 4) to the Chattahoochee River, particularly 

in the Atlanta area. In 1974, the Georgia Environmental Protection Division estimated that 

750 ft3/s of high-quality water would be needed 

downstream from Atlanta to meet water-quality 

standards and limited future water-supply withdrawals without equal additional flow of highquality water to the river (Environmental Protection Divison, 197 4). 

Several reaches of the river are used extensively for recreation. The mountainous headwater 

areas are popular for trout fishing and outdoor 

recreation. Lake Sidney Lanier, a popular waterresort area, has numerous public access areas, 

boat-launching facilities, campgrounds, marinas, 

yacht clubs, and cottages. Lake Sidney Lanier has 

a higher number of annual visitor days than any 

other U.S. Army Corps of Engineers facility in the 

Nation (Metropolitan Atlanta Water Resources 

Study Group, 1976). 

The reach from Buford Dam to Atlanta is 

periodically stocked with game fishes and provides recreation for fishermen, canoeists, and rafters. This reach has been designated as a National Recreation Area. The reach downstream 

from Morgan Falls to just upstream of the 

Peachtree Creek confluence, one of the most 

scenic reaches on the river, is the site for an annual raft race that involves thousands of participants and onlookers. 

West Point Lake, a U.S. Army Corps of Engineers impoundment created by the construction 

TABLE 3.-Estimated water-supply withdrawals, in cubic feet 

per second, from the Upper Chattahoochee River for the years 

1976 and 2000 

[From Metropolitan Atlanta Water Resources Study Group, 1976) 

Facility 1976 

Hall County1 ________________ 3.0 

Forsyth County1 ----------------

Gwinnett County1 _______________ _ 

City of Buford1 ______________ 1 

Gwinnett County __________ 12 

DeKalb County ------------ 91 

Fulton County ------------------ Cobb County ________________ 39 

City of Atlanta ____________ 134 

Total ________________ 280 

'Withdrawals upstream of Buford Dam. 

2000 

9 

2 

68 

1 

12 

188 

243 

116 

110 

749 

6 

TABLE 4.-Mean daily treated wastewater returns, in cubic feet 

per second, for 1976 and estimated returns for the year 2000 

to the Chattahoochee River and its tributaries for wastewater 

treatment facilities in the study area 

River 

Mile Facility 1

1976 22000 

Gainesville Linwood________________ 2.2 4.2 

Gainesville Flat Creek______________ 5.6 9.3 

Buford ---------------------------- 1.7 2.0 BigCreek __________________________ 4.1 17 

Crooked Creek -------------------- 1.8 12 

Johns Creek _______________________ 2.9 4.8 

300.56 Cobb Chattahoochee ________________ 15 31 

300.24 R. M. Clayton ______________________ 118 161 

297.50 Hollywood Road-------------------- 2.3 (-t) 

295.13 U.S. Air Force Plant No. 63 ________ 2.6 11 

294.28 South Cobb Chattahoochee __________ 13 48 

291.60 Utoy Creek ________________________ 21 44 

288.57 Sweetwater Creek ---------------------- 2.6 

283.54 Camp Creek ---------------------- 6.8 27 

281.46 Anneewakee Creek---------------------- 6.0 

281.45 Three-river Interceptor ------------------ 42 

275.95 Bear Creek ---------------------------- 7.7 

LaGrange Yellow Jacket5 ___________ 1.5 3.0 

Total ________________________________ 198 433 

•nata from monthly plant operating reports submitted to Georgia Department of Natural Resources, Environmental Protection Division. 2Data from Metropolitan Atlanta Water Resources Study Group (1976). 3

Data from U.S. Environmental Protection Agency. "'To be eliminated by year 2000. 5

Discharges into West Point Lake, not included in analysis. 

of West Point Dam in 197 4, is used for fishing, 

boating, camping, and swimming. 

NATURE OF THE PROBLEM 

The problems associated with water quality in 

the Upper Chattahoochee River Basin are for the 

most part related to urbanization. Urbanization 

has created large demands on the Chattahoochee 

River as the major source of water supply for Atlanta and the major transporter of municipal 

wastes from Atlanta. In 1976 about 280 ft.3/s was 

withdrawn from the river upstream of Peachtree 

Creek (RM(river mile) 300.54) for water supply, 

and about 180 ft3/s of secondary-treated wastewater was discharged into the river between the Atlanta and the Fairburn stations (RM 281.88). 

During periods of high flow, direct runoff from 

streets, parking lots, and construction sites in the 

Atlanta metropolitan area can contribute large 

suspended-sediment and total and dissolvedconstituent loads to the river and to West Point 

Lake. 

Sedimentation during the high-flow periods innundates valuable and fertile river-bottom lands 

and increases peak elevation of floods. Sedimentation also reduces the useful life of darn structures and reduces the esthetic and recreational 
potential of reservoirs; it also can increase the 

cost of maintenance and water-supply operations 

and restrict use of water in some industrial processes. 

Point sources, five WTF's (wastewater treatment facilities) and four thermoelectric plants, 

and nonpoint discharges contribute large nutrient loads to the Chattahoochee River and to 

West Point Lake. 

During periods of low flow, the availability of 

water downstream from Buford Dam is dependent 

to a large extent on the operation of the dam for 

peak hydroelectric-power generation. Generally, 

peak power is not generated on weekends, and 

flow in the Atlanta area is about 1,200 ft 3/s. 

In the 20-river-mile Atlanta-to-Fairburn reach 

about 130 ft3/s of water is withdrawn from the 

river for water supply, and about 180 ft 3/s of 

treated wastewater is returned to the river from 

seven WTF's. The estimated net flow (including 

tributary inflow) at the Fairburn station during 

weekend low-flow periods is about 1,400 fP/s, of 

which about 13 percent is treated wastewater. In 

this reach two baseload thermoelectric facilities 

discharge (circulate) about 900 ft 3/s of heated 

water to the river. 

The combined effects of public water-supply 

withdrawals, wastewater returns, and heated discharges during warm-weather low-flow periods 

cause low DO concentrations to occur in the river 

downstream from Atlanta. Table 5 shows the 

number of days and hours for each month during 

1977 that DO concentrations were less than 5.0 

mg/L in the Chattahoochee River near the FairTABLE 5.-Mean monthly air temperature and number of days 

and hours per month during 1977 in which the DO concen- tration was less than 5.0 mg!L at the Chattahoochee River near Fairburn monitor 

Mean monthly air Month Number of days Number of hours temperature' 

(DO <5 mg/L) (00 <5 mg/L) (°C) 

January __________ 0 

February __________ 0 

~arch ------------ 1 ApriL _____________ 0 ~ay ______________ 6 

June ______________ 9 

July ______________ 9 

August_ ___________ 9 

September ________ 9 

October __________ 16 

November ________ 8 

December ________ 1 

0 

0 

4 

0 

56 

121 

130 

58 

74 

234 

159 

9 

1.5 

5.6 

12.9 

17.2 

21.1 

25.1 

26.4 

25.4 

23.1 

15.3 

12.4 

5.6 

'Data source: Climatological Data, v. 81, no. 1-12, 1977, National Oceanic and Atmospheric Administration, Environmental Data Service, National Climatic Center, Ashville, N. C. 

7 

burn station monitor. An average daily DO concentration of 5.0 mg/L and not less than 4.0 mg/L 

in the reach of the river from the Peachtree Creek 

confluence to the Cedar Creek confluence is required at all times, unless violations occur during 

periods of urban storm runoff and (or) discharges 

from combined sewer overflows (Environmental 

Protection Divison, 1977). Average daily DO conI centrations of less than 5.0 mg/L occurred 31 percent of the hours in the month of October 1977. 

Figure 4 shows the average daily DO concentrations at the Fairburn station monitor (RM 

281.88) and the mean daily discharge at the Atlanta station (RM 302.97) during July 1977. Average daily DO concentrations of less than 5.0 

mg/L occur at Fairburn about a day later when 

streamflow at Atlanta is about 1,200 ft 3/s. 

In the year 2000, public water-supply withdrawals from the river are estimated to be 667 

ft3

/s. Future plans to modify the flow regime of the 

river to meet increasing water-supply demands 

include construction of a reregulation structure, 

dredging of the Morgan Falls reservoir (impounded by Morgan Falls Dam), and (or) changes 

in the hydropower releases from Buford Dam 

(U.S. Army Corps of Engineers, 1975). Wastewater returns in the Atlanta-to-Fairburn reach are 

estimated to be 538 ft3/s. Regardless of the alternative selected, the estimated flow (1,500 ft3/s) at 

the Fairburn station during weekend low-flow 

periods in the future will not be greatly different 

from today (1978). 

Data and information relative to water-quality 

problems in the Upper Chattahoochee River 

Basin are presented in the following sections entitled, ''Erosion and Sediment Transport," ''Flow 

and Temperature Models," "Point and Nonpoint 

Discharges," and "Biological Assessment." 

EROSION AND SEDIMENT TRANSPORT 

Soil erosion in the Upper Chattahoochee River 

Basin occurs mostly in the forms of sheet and rill, 

gully, ~nd channel erosion (Faye and others, 

1978). Sheet erosion is the predominate process. 

The potential for soil erosion is principally dependent on the quantity, intensity, ,and frequency of 

precipitation, soil composition and structure, land 

slope and slope length, and land-use practices. 

The amount of eroded material that reaches a 

stream and is transported as sediment, in turn, 

depends on the size and nature of the tributary 
FAIRBURN STATION MONITOR 

8 

7 

6 

5 

4~~~--~~~--~-L~--~-L~~~-L--L-~~--L-_L_J __ L__L_J __ ~_L~~~-L~~~_J 

4000r-.--.--.-.--.--.--.-.--.--.-,r-.--.--r-~~--~------~---.--~-r~--.--r-,r-.--, 

c 3500 

z 

0 

u 

w 

en 3ooo 

a: 

w 

a.. 

1- 2500 w 

w 

u. 

~ 2000 CD 

::::> 

u 

z 1500 

w 

(!) 

~ 1000 

I 

u 

en 

c 500 

ATLANTA STATION 

Minimum 

hydropower 

release 

oL-~~--L--L~ __ L__L_J __ ~_L~L_~_L __ L_~~--L__L_J __ L__L_J __ L_-L~--~_L~L_~~ 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 

DAY 

FIGURE 4.-DO concentrations at the Fairburn station monitor and mean daily discharge at the Atlanta station during July 

1977. 

drainage area, the rainfall intensity and frequency of occurrence, and the character of land 

use and erosion controls, natural or manmade. 

8 

The Universal Soil Loss equation (Wischmeier 

and Smith, 1965) was used to compute sheet erosion in nine selected watersheds. Land use in eSich 
watershed was predominantly urban, rural, or 

forested. The range of topographic and climatic 

conditions relative to all the watersheds is assumed characteristic of the basin as a whole. 

Drainage area of the watersheds ranged from 

about 3 to 150 mi2 • Average annual yields of erosion in the nine watersheds ranged from about 

900 to 6,000 tons/mi2/yr (tons per square mile per 

year). The greatest yields occurred in watershed 

with the largest percentages of agricultural and 

transitional land uses. The lowest yields occurred 

in highly urbanized watersheds. An evaluation of 

the effects of timber harvesting on average annual sheet erosion indicated that post-harvest 

erosion yields were several orders of magnitude 

greater than pre-harvest yields in the same areas. 

Streams in the basin transport sediment from a 

variety of sources. Silt and clay are supplied 

mostly by overland flow. Sand and gravel are 

generally available from stream beds and banks. 

Suspended loads consist mostly of silt and clay; 

bed and unmeasured loads are mostly sand and 

gravel. 

Average annual yields of suspended sediment 

calculated from measurements of sediment discharge at stations draining the nine watersheds 

for which sheet erosion was calculated ranged 

from about 300 to 800 tons/mi2/yr. Sediment discharges were greatest at stations draining urban 

watersheds and least at stations draining predominantly forested watersheds. A large part of 

the sediment discharged in urban streams was 

considered to be derived from stream-channel 

erosion. Unmeasured sediment discharge at four 

stations ranged from about 6 to 30 percent of the 

total computed annual discharge of sediment. 

Erosion and sediment discharge rates about 

2,000 and 300 tons/mi2/yr, respectively, at stations draining watersheds where man's impact is 

minimal were considered indicative of background rates in the basin. 

Suspended sediment also transports significant 

quantities of chemical constituents in basin 

streams. Curves that relate the concentration of 

suspended chemical constituents to suspendedsediment concentration were developed at most 

water-data stations. In general, the suspended 

constituent-sediment concentration relation conformed to the geometric relation, 

9 

where Cs = the suspended chemical constituent 

concentration in milligrams per liter, Sse = concentration of suspended silt plus clay in milligrams per liter, and a and bare constants relative 

to the occurrence of each constituent at individual 

water-data stations. A summary of the regression 

equations relating some suspended-constituent 

concentrations to silt plus clay concentrations is 

listed in table 6. The omission of regression information for particular constituents indicates 

that a functional relation could not be established. 

Average annual constituent discharges were 

computed using the regression relations discussed 

previously and are listed in table 7 along with 

total annual constituent discharges. Suspended 

phosphorus ranged from about 31 to 95 percent of 

the total annual discharges of phosphorus and averaged about 76 percent. Suspended nitrogen discharges ranged from about 7 to 53 percent of the 

total annual nitrogen discharges and averaged 29 

percent. Corresponding ranges for suspended organic carbon were 18 to 71 percent with an average of 43 percent. At every station, most of the 

trace-metal discharges were in the suspended 

phase. 

The effects of land use on suspendedconstituent discharges were determined by comparing suspended-constituent yields (table 8) at 

stations draining watershed with different landuse characteristics. The yields of suspended phosphorus and nitrogen from urban watersheds were 

greater by a factor of two than corresponding 

yields from forested watersheds. Similarly the 

yields of suspended zinc and lead from urban 

areas exceeded corresponding yields from forested 

areas by an order of magnitude. The differences in 

constituent yields indicate there is more opportunity in urban watersheds than in forested watersheds for nutrients and most trace metals to come 

into contact with sediments. The data further indicate that sediments act as a sink for nutrients 

and some trace metals, thus reducing the dissolved concentrations of these constituents in 

urban streams. 

FLOW AND TEMPERATURE MODELS 

Digital models of transient flow and heat 

transport were used to evaluate natural Chattahoochee River temperatures and analyze the 

impact of flow regulation at Buford Dam and ef-
TABLE 6.-Summary of regression data relating suspended 

Station name Suspended phosphorus as P Suspended nitrogen as N Suspended 

Correlation Number Correlation Number a b coefficient of samples a b coefficient of samples a b 

Chattahoochee River near Leaf ________________________________________ 0.00274 0.746 0.97 Soque River near Clarkesville -------------------------------- .00248 .834 1.0 Chestatee River near Dahlonega _ -----------~- ____________________ .00132 .942 .99 

BiXl<;h~~~t:a~ _____________ ------------------------ .00681 .639 .96 Chattahoochee River at Atlanta ____________________ ------------- _______ .0103 .500 .91 N. Fork Peachtree Creek near Atlanta ------------------------------ .00161 .504 .96 S. Fork Peachtree Creek at Atlanta -------------------------------- .00330 .781 .99 Peachtree Creek at Atlanta ________________________________________ .00703 .646 .98 Woodall Creek 

Nancy at Atlanta Creek T;ib~tit-ry _____________________________ .0665 .372 .91 

near Chamblee __________________________________ .0185 .391 .90 Nancy Creek at Atlanta ________________________________________ .00116 .909 .99 Chattahoochee River near Fairburn ____________________________________ .0413 .379 .61 Snake Creek near Whitesburg ____________ ------------------- _______ 

Chattahoochee River .000911 .920 .99 

near Whitesburg __________________________________ .0198 .484 .85 

fluent discharges from the Atkinson-McDonough 

powerplants on river temperatures between Atlanta and Whitesburg (Faye and others, 1978). 

The flow model used in a finite-difference approximation of the one-dimensional continuity 

and momentum equation for gradually varied 

flow is identical to those used by Amien and 

Fang (1970). Boundary conditions for the flow 

model were defined at the Atlanta and Whitesburg gages as discharge and stage, respectively. 

The temperature model solves a finitedifference approximation of the one-dimensional 

equation describing the continuity of thermal energy in open channels and used observed temperatures at the Atlanta gage as boundary conditions. 

Flow, temperature, and meteorological data 

collected during two 8-day periods beginning July 

12, 1976, and August I, 1976, were used to calibrate and verify the flow and temperature models. 

Examples of the results of model calibration are 

shown in figures 5 and 6. 

Use of the models to analyze the impact on river 

temperatures of powerplant heat loads and bottom, cold-water releases from Buford Dam indicated that the combined effect of flow reregulation 

and thermal powerplant effluents resulted in 

mean daily river temperatures equal to or less 

than mean natural temperatures downstream 

from the powerplants. An analysis of historical 

10 

8 0.0137 0.714 0.98 0.0359 0.944 

9 .000493 1.27 .91 8 .818 .441 

11 .00167 .988 .87 10 .00255 1.51 

12 .0290 .528 .93 .0157 1.09 

15 .00116 1.06 .87 9 

12 .000600 1.21 .66 9 

12 .00203 .983 .90 11 

12 .000454 1.23 .93 12 

7 .0163 .641 .96 6 .155 .705 

7 .00247 1.24 

13 6.91xl0-• 1.49 .89 11 .201 .585 

16 .00377 1.37 

.00530 .827 .96 6 .0446 .755 

11 .00324 1.34 

river and air temperatures also provided the same 

basic conclusion. 

The models were also used to simulate river 

temperature using year 2000 estimated flow conditions and meterological data collected during 

1976. Except for periods of peak water-supply 

demand, simulated river temperatures for the 

year 2000 were changed little from observed, 

present-day (1978) temperatures. 

POINT AND NONPOINT DISCHARGES 

Point-source discharges, seven WTF's and the 

Atkinson-McDonough thermoelectric plants, 

occur in the Chattahoochee River or its tributaries in the Atlanta-to-Fairburn reach 

(Stamer and others, 1978). The mean daily flow of 

the WTF's in 1976 was about 180 ft3/s (table 4), or 

about 4 percent of the mean daily flow of 4,400 

ft3/s at the Whitesburg Station. 

Non point sources of discharge include all 

sources other than the seven WTF's and the 

Atkinson-McDonough powerplants. The sources 

include runoff from urban, rural, and forested 

areas. Urban nonpoint discharges are characterized by the water quality of Peachtree Creek at 

Atlanta, rural nonpoint discharges by the waterquality characteristics of Big Creek near Alpharetta, and forested nonpoint discharges by 

Snake Creek near Whitesburg. 
constituent and suspended silt plus clay concentrations 

organic carbon Suspended lead 

Correlation Number Correlation Number coefficient of samples a b coefficient of samples a 

0.92 9 0.00387 

1.0 5 .00285 

.93 10 0.00200 0.539 0.82 12 .00112 

.69 10 .000964 .639 .82 9 

.00205 .550 .67 11 .00389 

.00217 .638 .94 .00224 

.00586 .591 .94 9 .00115 

.00349 .655 .93 12 .00546 

.93 9 .00134 .463 .95 .0461 

.94 .000346 .890 .87" 4 .00319 

.83 9 .000836 .789 .89 8 .000122 

.82 12 .00208 .625 .77 9 .00519 

.90 5 

.95 13 .00260 .610 .90 .00140 

POINT DISCHARGES 

Average annual loads and average daily concentrations of selected constituents for each of the 

seven WTF's are given in table 9. Table 9 indicates that (1) dissolved solids are the largest of 

the constituent loads, (2) 51 percent of the phosphorus load is dissolved, (3) 69 percent of the nitrogen load is dissolved, ( 4) the total nitrogen to 

total phosphorus concentration ratio is 4.6:1, and 

(5) trace-element concentrations are low in comparison to other constitutent concentrations. 

NONPOINT DISCHARGES 

Table 10 shows the average annual yields and 

average daily concentrations for selected constituents from urban, rural, and forested areas. 

Average annual yields and average daily concentrations are greatest for suspended sediment, dissolved solids, total and dissolved nitrogen, total 

and dissolved phosphorus, NH4 -N (ammonium as 

nitrogen), COD (chemical oxygen demand), BODu 

(ultimate biochemical oxygen demand), arsenic, 

copper, lead, and zinc in the urban area. The rural 

area has the greatest average annual yields and 

average daily concentrations for N03-N (nitrate 

as nitrogen), TOC (total organic carbon), and 

DOC (dissolved organic carbon). Average annual 

yields and average daily concentrations are smallest in the forested area. 

11 

Suspended zinc Suspended copper 

Correlation Number Correlation Number 

b coefficient of samples a b coefficient of samples 

0.477 0.91 8 

.525 .93 6 0.000306 0.802 0.96 7 

.701 .87 8 .000447 .900 .96 9 

.443 .95 8 .000253 .872 .92 12 

.608 .80 8 

.767 .97 8 .00639 .343 .85 8 

.544 .91 13 .00594 .761 .82 15 

.290 .88 .000953 .699 .95 

.545 .87 4 

1.07 .92 10 .000103 .911 .97 10 

.488 .70 10 .00665 .300 .66 10 

.000313 .366 .91 5 

.728 .90 10 .00106 .622 .81 10 

The concentration data in table 10 indicate that 

(1) about 65 percent of the nitrogen is dissolved 

and that N03 -N composes about 50 percent of the 

dissolved nitrogen, (2) about 10 percent of the 

phosphorus is dissolved, and (3) about 60 percent 

of TOC is dissolved. 

RELATION OF NONPOINT CONSTITUENT YIELDS 

TO URBANIZATION 

Average annual constituent yields from 15 

subbasins in the Upper Chattahoochee Basin 

were related to percentage of urbanization in each 

of these subbasins. Generally, constituent yields 

increase with increasing urbanization, particularly for dissolved constituents. Strong relationships of constituent yields to percentage of urbanization were indicated for dissolved solids, 

BODu, total and dissolved phosphorus, total and 

dissolved nitrogen, and total lead. In contrast, 

COD, TOC, DOC, and suspended nitrogen and 

phosphorus do not appear to be significantly related to percentage of urbanization, but the yields 

of these constituents are generally higher in 

urban than in the forested areas. 

The relationship of average annual yields of 

dissolved solids and BODu is shown in figure 7. 

The BODu yield from North Fork Peachtree Creek 

tributary (at Meadowcliff Road near Chamblee) 

as shown by the open circle in figure 7 was not 

included in the regression. Although the basin is 
TABLE 7.--Summary of average annual suspended and total constituent discharges 

Organic carbon Phosphorus as P Nitrogen as N Lead Zinc 

Ratio of Ratio of Ratio of Ratio of Ratio of Sus- sus- ' Sus- sus- Sus- sus- Sus- sus- Sus- susTotal pended pended to Total pended pended to Total pended pended to Total pended pended to Total pended pended to 

dis- dis- total dis- dis- dis- total dis- dis- dis- total dis- dis- dis- total dis- dis- dis- total dis- Station name charge charge charge charge charge charge charge charge charge charge charge charge charge charge charge 

(tons/yrl (tons/yrl (tons/yrl (percent I (tons/yrl ltons/yrl (percentl (tons/yrl (tons/yrl (percent) (tons/yr) (tons/yri (percent) (tons/yrl (tons/yrl (percent) 

Chattahoochee River near Leaf ___________________________ 960 510 53.1 18 16 88.9 130 69 53.1 7.5 7.5 100 Soque River near Clarkesville ------------------- 1,700 1,200 70.6 25 21 84.0 100 32 32.0 7.0 5.9 84.3 Chestatee River near Dahlonega __________________________ 2,000 1,400 70.0 27 24 88.8 200 39 19.5 5.H 5 86.2 7.H 5.8 74.4 

1--' Big Creek near Alpharetta -------------------------------- 1,300 500 38.5 15 14 93.3 140 31 22.1 2 2 100 

t-.:l Chattahoochee River at Atlanta __________________________________ 180 56 31.1 1,700 120 7.1 36 14 ""·~ 47 16 34.0 Chattahoochee River at Atlanta' -------------------------------- 96 53.3 56 3.3 22 61.1 31 66.0 N. Fork Peachtree Creek near Atlanta 11 8.6 78.2 75 19 25.3 4.9 4.5 91.8 2.5 2.1 84.0 

S. Fork Peachtree Creek at Atlanta ----========================== 11 10 90.9 71 22 30.9 6.4 6.1 95.3 4.2 3.4 81.0 Peachtree Creek at Atlanta ______________________________________ 32 29 90.6 200 62 31.0 16 15 93.7 16 13 81.3 Woodall Creek at Atlanta 250 46 18.4 16 5.3 33.1 46 3.7 R.O 1.8 1.5 83.0 3.4 2.7 79.4 Nancy Creek Tributary nea;-Ch~~b~~~-==================== 38 1.9 4.8 .44 .30 68.2 .11 .046 38.3 .12 .096 80.0 

Nancy Creek at Atlanta --------------------------- 670 260 38.8 11 10 90.9 77 28 36.4 4.5 3.6 80.0 3.6 3.1 86.1 

Chattahoochee River near Fairburn ------------------------28,000 5,800 20.7 1,300 410 31.5 140 68 48.6 200 86 43.0 Chattahoochee River near Fairburn' ------------ -------------- 2,500 8.9 96 7.4 22 15.7 31 15.5 Snake Creek near Whitesburg ____________________________ 290 110 37.9 6 5.7 95.0 41 19 46.3 Chattahoochee River near Whitesburg ___________________ .. __ 36,000 8,000 22.2 1,300 410 31.5 1'1'1· FFI 170 100 58.8 220 110 50.0 

Chattahoochee River near Whitesburg' -------------------------- 25,000 6.9 96 7.4 22 12.9 31 8.3 

'Discharge attributed to regulated flow. 'Discharge attributed to regulated flow. Equals computed discharge at the Chattahoochee River at Atlanta. 
TABLE B.-Annual yields of suspended constituents, in tons per square mile, from representative land-use watersheds 

Phosphorus Nitrogen Organic Lead Zinc Copper Chromium Arsenic 

carbon 

Forest~~~~~~~~~~~~~~~~~~~~ ~ ~ ~ ~ ~ ~ ~ ~ ~ -- ~ ---- _0.15 0.36 7.4 0.033 0.048 0.034 0.027 0.0011 

Urban-~-~~~--~~~~-- -------------- -------- .33 .71 8.1 .16 .13 .050 .023 .0038 

Rural -------------- ----------------------- .19 .43 6.9 .028 .0028 

760 

A EXPLANATION 

8 --Observed 

-·······Computed 

I- 755 w \ w 

LL 

z . . ..__, 

ui 

0 

::::> 

I- 750 ~ 12 13 14 15 16 17 18 19 _J 

740L--L----~----L-~---~I ____ L_I ___ ~I--~I _____ ~I 

12 13 14 15 16 17 18 19 

< TIME, IN DAYS TIME, IN DAYS 

w 

u 755.-,-----,----.----.----.----.----.----.-~ 

~ a: 

::::> 

(/) 

a: 

w 

~ 

B 

750 

745 

12 13 14 15 16 

TIME, IN DAYS 

ui 690 

0 

::::> 

I-

~ _J 

< 

wluw 

<If 685 LL 

a:z 

::::>-

(/) 

a: 

w 

I-

< 

~ 680 

12 

EXPLANATION 

--Observed 

··---·-· Computed 

17 18 19 

13 14 

725 

720 

15 16 

D 

12 13 14 15 16 

TIME, IN DAYS 

EXPLANATION 

---- Observed 

17 18 19 

TIME, IN DAYS 

EXPLANATION 

--Observed 

--··--·Computed 

17 18 19 

FIGURE 5.-0bserved and computed stages of the Chattahoochee River during the period July 12-19, 1976. A, at Atlanta, B, at 

the City of Atlanta Water Works, C, at the plant McDonough outfall, D, near Fairburn, and E, near Whitesburg. 

13 
en 

:::> 

(i) 

_. 

w 

u 

en 

w 

w 

a: 

(!) 

w 

0 

z 

u.i' 

a: 

:::> 

I-

<( 

a: 

w 

0.. 

:E 

w 

I24 

22 

20 

18 

16 

14 

24 

22 

20 

18 

16 

14 

32 

30 

28 

26 

24 

22 

20 

18 

30 

28 

26 

24 

22 

20 

28 

26 

24 

22 

2 3 4 5 6 7 8 

TIME, IN DAYS 

FIGURE G.-Observed and computed temperatures of the Chattahoochee 

River. A, at Atlanta, B, at the plant McDonough intake, C, at Georgia 

Highway 280, D, near Fairburn, and E, near Whitesburg. 

14 
TABLE 9.-Magnitude and nature of point discharges for selected constituents for the year 1976 

Dissolved Ultimate 

Dissolved Dissolved orthophos- biochem- Chemical 

Total Dissolved nitrate ammonium Total Dissolved phate as ical oxy- oxygen 

Facility nitrogen nitrogen nitrogen nitrogen phosphorus phosphorus phosphorus gen demand demand 

Cobb Chattahoochee ________________ 330 160 4.4 130 66 27 1.1 1,200 1700 

R. M. McClayton ------------------2,300 1,500 32 1,030 440 190 17 13,000 18,000 

Hollywood Road-------------------- 50 37 .39 30 10 6.8 .96 220 240 

U.S. Air Force Plant No. 6 __________ 14 11 9.8 .24 .80 .68 .066 17 36 

South Cobb Chattahoochee -------- 200 170 8.2 120 75 52 4.5 620 1,200 

Utoy Creek ------------------------ 270 240 7.0 160 68 42 1.6 960 1,400 

Camp Creek 76 71 60 2.4 33 29 1.0 100 250 

Sum of annual loads 

(tons/yrl __________________ 3,200 2,200 120 1,500 690 350 26 16,000 23,000 

Mean daily 

concentration (mg/L) 1 

------------ 18 12 0.70 8.5 3.9 2.0 0.15 90 130 

TABLE 9.-Magnitude and nature of point discharges for selected constituents for the year 1976-Continued 

Total Dissolved organic organic Suspended Dissolved Total Total Total Total Total Facility carbon carbon solids solids arsenic chromium copper lead zinc 

Cobb Chattahoochee ________________ 410 120 2,250 3,500 0.015 0.37 0.30 0.56 1.4 

R. M. Clayton ____________________ 5,000 1,300 9,880 28,800 .51 14 10 19 54 

Hollywood Road __________________ 56 21 143 567 .0023 .046 .045 .076 .098 

U.S. Air Force Plant No. 6 ________ 9.3 7.2 7.4 875 .00064 .10 .021 .044 .074 

South Cobb Chattahoochee ________ 240 110 636 3,120 .012 .24 .22 .59 1.0 

Utoy Creek ______________________ 520 190 564 5,120 .021 .54 .31 1.2 1.5 

Camp Creek -------------------- 69 38 111 1350 .0067 .13 .061 .11 .28 

Sum of annual loads 

(tons/yrL _________________ 6 300 1800 13 600 43 300 0.57 15 11 22 58 

Mean daily 

concentration (mg/L) 1 

---------- 36 10 77 245 0.003 0.09 0.06 0.12 0.33 

'Computed from the sum of the annual loads prior to rounding. 

TABLE 10.-Average annual yields and average daily concentrations for selected constituents for urban, rural, and forested 

nonpoint discharges 

[Units for yield are tons per square mile per year; units for concentration are milligrams per liter) 

Dis- Ultimate 

Dis- solved Dis- bioSus- Dis- solved Total solved chem- D1sDis- pended Total solved nitrate mum phos- phos- ical Chemical Total solved 

solved sedi- nitro- nitro- nitro- nitro- pho- pho- oxygen oxygen organic organic Total Total Total Total 

Land use solids ment gen gen gen gen rus rus demand demand carbon carbon arsenic copper lead zinc 

Urban: 

Yield ____ 113 775 2.3 1.6 0.76 0.30 0.37 0.038 16 30 14 8.3 0.005 0.059 0.18 0.18 

Average 

concentration __ 71.4 480 1.5 1.0 .48 .19 .23 .02 10 19 8.8 5.3 .003 .037 .12 .12 

Rural: 

Yield 59.6 333 1.9 1.5 .83 .11 .20 .015 8 24 18 11 .003 .029 .028 .053 

Average 

concentration __ 36.6 205 1.2 .94 .51 .07 .13 .01 5 14 11 6.5 .002 .018 .017 .033 

Forest: 

Yield 32.2 359 1.1 .59 .26 .062 .16 .008 7.6 19 7.9 4.9 .002 .032 .041 .046 

Average 

concentration __ 20.7 230 .71 .38 .17 .04 .10 .01 4.8 12 5.1 3.1 .001 .021 .025 .035 

15 
150 

140 Dissolved solids 

130 (/) 

z 

ocr: 120 1-<( w ~>- 110 '0: Ow Lda.. 100 

;>:w ...J enCl~ 90 

::iw 

ocr: 

(/)<( 80 

l:::l 

oo 

~(/) 70 

0 ...Ja: Ow 

(/)a_ 60 (/) 0 

Ci 

50 

40 

30 

0 10 20 30 40 50 60 70 80 

URBANIZATION, IN PERCENT 

0 

ci ...J 

w 

>=a: 

Q<( 

zw 

<e>-

~a: 

ww 

oa.. 

zw w:::! 

~~ 

xw 

ocr: <( 

...J:::> <Co 

~(/) 

~a: ww 

~a.. 

u 

ocn 

-z ceo 

WI-

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~-

i= ...J 

:::> 

90 100 

24 

4 

0 

0 

Ultimate biochemical 

oxygen demand 

0 

0 

0 

0 

10 20 30 40 50 60 70 80 90 100 

URBANIZATION, IN PERCENT 

FIGURE 7.-Relationship of average annual yields of dissolved solids and BODu to percentage of urbanization. 

84 percent urbanized, it is mostly residential. The 

BOD11 yield of 6.2 tons/mi2/yr from the residential 

area is about the same as those from forested 

areas. Thus, it appears that some urhan land uses 

do not substantially increase the yields of some 

constituents. 

AVERAGE ANNUAL URBAN, RURAL, AND FORESTED 

NONPOINT DISCHARGES TO THE UPPER 

CHATTAHOOCHEE RIVER 

Urban, rural, and forested nonpoint constituent 

loads were computed for two reaches of the river 

using the following equation: 

where, 

L = nonpoint load in tons, 

U =urban area in square miles (table 1), 

Uu =urban constituent yield in tons per 

square mile per year (table 10), 

R =rural area in square miles (table 1), 

R u = rural constituent yield in tons per 

square mile per year (table 10), 

F =forested area in square miles (table 1), 

F u = forested constituent yield in tons per 

square mile per year (table 10). 

16 

Constituent loads computed from this equation 

were compared to nonpoint constituent loads 

computed from river measurements. Constituent 

loads from river measurements were computed by 

subtracting the point-source inputs to each reach 

of the river from the total inputs between the 

upper and lower stations in each reach. 

A comparison of the nonpoint loads computed 

by the two methods is shown in table 11. In general, nonpoint constituent loads can be estimated 

from urban, rural, and forested nonpoint discharge constituent yields. 

The data in table 11 indicate that on the average annual basis nonpoint loads in the reaches 

are as follows: 

1. Atlanta to Fairburn, the upper reach (39.8, 

11.7, 48.5 percent for urban, rural, and 

forested). Urban loads are equal to or 

greater than the sum of rural and forested; 

2. Fairburn to Whitesburg, the lower reach (6.5, 

16.8, 76.7 percent for urban, rural, and 

forested). Forested loads are greater than the 

sum of urban and rural. 

3. Atlanta to Whitesburg, the inclusive reach 

(27.2, 13.6, 59.2 percent for urban, rural, and 

forested). Urban loads are the greatest and 

rural the least. 
TABLE H.-Comparison of average annual nonpoint constituent loads, in tons per square mile per year, computed from urban, 

rural, and forested yields to nonpoint constituent loads computed from river measurements 

Dissolved Total solids nitrogen 

Atlanta to Fairburn: tJrban __________________________ 27,400 560 Rural __________________________ 4,230 130 Forest __________________________ 9,550 330 

Total (rounded) ______________ 41,200 1,000 River measurements ________________ 63,300 1,200 

Fairburn to Whitesburg: tJrban __________________________ 2,720 55 Rural __________________________ 3,700 120 Forest __________________________ 9,140 310 

Total (rounded) ______________ 15,600 480 

River measurements ________________ 6,000 700 

Atlanta to Whitesburg: tJrban __________________________ 30,100 620 

Rural __________________________ 7,930 250 Forest __________________________ 18,700 640 

Total (rounded) ______________ 56,700 1,500 

River measurements ________________ 69,900 1,900 

COMPARISON OF MAGNITUDE 

OF POINT AND NONPOINT DISCHARGES 

TO THE UPPER CHATTAHOOCHEE RIVER 

Most of the average annual (fig. 8) and March 

12-15, 1976, storm-constituent loads (fig. 9) at 

the Whitesburg station (RM 259.85) are from 

nonpoint discharges. On an average annual basis, 

nonpoint discharges contribute 78 percent of the 

dissolved-solids load, 48 percent of the total phosphorus load, 51 percent of the total nitrogen load, 

82 percent of the TOC load, and 74 percent of total 

copper, lead, and zinc loads at Whitesburg. During the storm period of March 12-15, 1976, nonpoint discharges contributed 90 percent of the 

dissolved-solids load, 84 percent of the total phosphorus load, 79 percent of the total nitrogen load, 

and more than 90 percent of the arsenic and lead 

loads at Whitesburg (fig. 9). Most of the low-flow 

(June 1-2, 1977) constituent loads at the 

Franklin station (RM 235.46) were from point 

discharges (table 12). Point discharges contributed 90 percent of the total phosphorus load, 92 

percent of the POrP load, 78 percent of the total 

nitrogen load, and 80 percent of the inorganic nitrogen as nitrogen load. 

A comparison of the high- and low-flow constituent loads downstream from Atlanta shows (1) 

high-flow loads are greater than low-flow loads, 

(2) most of the high-flow loads are from non point 

discharges, and (3) constituent concentrations resulting from these loads are low. High-flow loads 

Dissolved 

inorganic Total 

Dissolved nitrogen Total Dissolved organic Total 

nitrogen as nitrogen phosphorus phosphorus _ carbon lead 

390 260 90 9.2 3,400 44 

110 67 14 1.1 1,300 2 

170 95 47 2.4 2,300 12 -- --

670 420 150 13 7,000 58 

700 1,000 430 89 6,700 82 

39 8.9 .92 340 4.3 

93 12 .93 1,100 1.7 

170 45 2.3 2,200 12 - --

300 66 4.1 3,600 18 

100 10 10 8,000 30 

430 99 10 3,700 48 

200 26 2.0 2,400 3.7 

340 92 4.7 4,500 24 

970 220 17 11,000 76 

800 440 99 15,000 110 

17 

generally occur during the cooler months of the 

year, December through April. The minimum DO 

concentration at the Fairburn station monitor 

during these months was greater than 6.0 mg/L 

(fig. 10). The maximum phytoplankton concentration in West Point Lake was 27,000 cells/mL. 

Low-flow loads are mostly from point discharges, 

and constituent concentrations in the river resulting from these loads are large compared to constituent concentrations in the river resulting 

from nonpoint discharges (table 12). Point-source 

loads are relatively constant in comparison to 

non-source loads. The minimum DO concentration at the Fairburn station monitor during the 

period May through November 1977 was 3.6 

mg/L. The maximum phytoplankton concentration in West Point Lake was 560,000 cells/mL. 

PRESENT AND FUTURE EFFECTS OF POINT AND 

NONPOINT DISCHARGES ON THE 

DISSOLVED-OXYGEN REGIME OF THE UPPER 

CHATTAHOOCHEE RIVER 

The effects of point and non point discharges on 

the DO regime in the Atlanta (RM 302.97)-toFranklin (RM 235.46) reach of the river were determined (Stamer and others, 1978) for two lowflow periods, August 31 to September 9, 1976, and 

June 1-2, 1977. Data used in the determination of 

these effects on the DO regime are shown in table 

13. The method used in the determination was the 

Velz (1970) rational method of stream analysis. 
TOTAL NITROGEN 7000 ..----------, 

6000 

5000 

4000 

3000 

2000 

1000 

OLL-~~--W--~ 

1400 

1200 

1000 

800 

600 

400 

200 

0 1-L. _ ___._..___-L.L __ .LJ 

a: BIOCHEMICAL OXYGEN 

<{ DEMAND ULTIMATE 

~ 60,000 

a: 50,000 

w 

D.. 

en 

z 

~ 

z 

ci 

<{ 

0 

...J 

40,000 

30,000 

20,000 

10,000 

TOTAL COPPER 

TOTAL 

ORGANIC CARBON 40,000 ..------------, 

DISSOLVED NITROGEN 

CHEMICAL OXYGEN 

DEMAND 70,000 ~-------~ 

60,000 

50,000 

40,000 

30,000 

20,000 

10,000 

0 LL---L..___-L.L __ u 

TOTAL LEAD 

DISSLOVED 

ORGANIC CARBON 30,000 .------------, 

20,000 

10,000 

0 1-L. _ ___._..___-L.L __ LJ 

DISSOLVED INORGANIC NITROGEN 

AS NITROGEN 

DISSOLVED ORTHOPHOSPHATE 

AS PHOSPHORUS 

TOTAL ARSENIC 

5.0 

4.0 

3.0 

2.0 

1.0 

TOTAL ZINC 

DISSOLVED SOLIDS 

{) L.-1-_ _..._..__ _ _,LL __ ._, 

FIGURE B.-Magnitude and nature of average annual point (crosshatched) and nonpoint (clear) 

loads for selected constituents at stations on the Chattahoochee River at Atlanta, Fairburn, 

and Whitesburg. 

18 
TOTAL NITROGEN DISSOLVED NITROGEN 

DISSOLVED INORGANIC 

NITROGEN AS NITROGEN 70~------------~ 

60 

50 

40 

30 

20 

10 

0 LJ._ __ _Ll. __ ___.l...J__ __ ...LJ 

DISSOLVED SOLIDS TOTAL PHOSPHORUS DISSOLVED PHOSPHORUS 3000 30 5.0 

U) 2500 4.0 z 

0 2000 20 1- 3.0 

z 1500 

ci" 2.0 

1000 10 

<t 

0 500 1.0 

...J 

0 0 0.0 

TOTAL ORGANIC CARBON TOTAL ARSENIC TOTAL LEAD 

800 0.20 5.0 

4.0 600 0.15 

3.0 

400 0.10 

~ ~ 2.0 Ol 

::1 ::1 :; .c c:: .c c:: .c 200 Ill 0.05 .f9 :; Ill .f9 :; Ill 

~ c:: -e ~ 1.0 c:: -e ~ :E (0 :E (0 :E 

3: ~ "iii 3: ~ "iii 

0 0.0 u. 0.0 u. ~ 

FIGURE 9.-Magnitude and nature of point (crosshatched) and nonpoint (clear) loads for 

selected constituents at stations on the Chattahoochee River at Atlanta, Fairburn, and 

Whitesburg during the storm period of March 12-15, 1976. 

The DO balance is affected by deoxygenation 

and reoxygenation. Deoxygenation results from 

microbial aerobic oxidation of decomposable organic material and biological oxidation of reduced 

forms of nitrogen. The amount and rate of 

deoxygenation in the river are dependent on the 

magnitude and distribution of BODu and NH4-N 

loads, the time of water passage from reach to 

reach, and the water temperature. Stream 

reoxygenation depends on the magnitude of 

stream-flow and increments of tributary inflow 

19 

along the watercourse, and reaeration from the 

atmosphere. Atmospheric reaeration depends on 

water temperature, channel geometry, occupied 

channel volume, and the oxygen deficit. 

Rates of deoxygenation and reoxygenation were 

developed from extensive analyses of river and 

tributary water and wastewater samples and 

from detailed cross-section measurements of the 

river channel. For this purpose, two intensive 

synoptic surveys, August 31 to September 9, 

1976, and June 1-2, 1977, were conducted during 
TABLE 12.---Constituent loads at the Atlanta, Fairburn, Whitesburg, and Franklin stations, constituent loads from point discharges, and resulting constituent concentrations at Franklin, June 1-2, 1977 

[Results in tons per day except where indicated] 

Total 

Total inorganic 

Total orthophosphate Total nitrogen as Flow 

Stream station Dissolved 

solids phosphorus as phosphorus nitrogen nitrogen (ft1s) 

i\tlanta ---------------------------------------- 99 

Fairburn ----------------------------------------308 VVhitesburg ______________________________________ 328 

Franklin ________________________________________ 334 

Point discharges _________________________________ 148 

Constituent concentration 

at Franklin (mg/L) ---------------------------- 62.2 

Nonpoint constituent 

concentration (mg/L) -------------------------- 38.2 

a: 13 w 

I-

::i 12 a: 

w 

a.. 11 (/) 

~ 

<( 10 

¥1' a: 

(!) 

::i 9 ....J 

~ 

~ 8 

z 

w 7 

(!) 

>- X 6 

0 

Q 

w 5 

> ....J 

0 4 (/) 

(/) 

0 3 

Oct. Nov. Dec. Jan. Feb. Mar. 

0.11 0.075 1.46 0.93 1,150 

2.69 1.82 12.07 8.04 1,610 

2.72 1.83 12.30 8.24 1,890 

2.72 1.83 12.44 8.34 1,990 

2.46 1.69 9.7 6.65 185 

0.51 0.34 2.3 1.6 

0.053 0.029 0.56 0.35 

Apr. May June July Aug. Sept. 

FIGURE 10.-Mean daily DO concentrations at the Chattahoochee River near Fairburn station monitor, October 1976 to 

September 1977. 

steady-state low-flow river conditions. The June 

1-2, 1977, survey was used to develop the stream 

self-purification factors for definition of causeeffect relationships. The August 31 to September 

9, 1976, survey was used to verify the cause-effect 

relationships developed in June 1977. 

Laboratory measurements of BOD concentrations were made at intervals during a 20-day 

incubation period to define the carbonaceous rate 

of decay, kt. and BOD11 • A nitrification inhibitor, 

1-allyl-2-thiourea, was added to water samples for 

BOD analysis (Hines and others, 1978). A mean 

k 1 of 0.07 (base 10) at 20°C was determined from 

laboratory BOD samples from point and nonpoint 

20 

discharges and was adjusted for prevailing water 

temperatures in the study reach. The k 1 selected 

was applied to a mass-balance integration of 

point- and nonpoint source BOD11 loads of 36 and 

21 tons/day, respectively, in the Atlanta-toFranklin reach of the river at the prevailing time 

of passage as shown by curve A in figure 11. From 

curve A, the maximum accumulated residual 

BODu load, 49 tons/day, occurs at the Sweetwater 

Creek confluence (RM 288.58) and decreases to a 

residual of 34 tons/day at Franklin (RM 235.46). 

A comparison of the observed and computed 

river BOD11 loads converted to concentrations in 

milligrams per liter is shown in figure 12. The 
TABLE 13-Chemical, physical, and flow data used to comute DO profiles in the Atlanta-to-Franklin reach of the river for the years 

1977 and 2000 

Ultimate biochemical Ammonium Dissolved oxygen Water temperature (°C) Flow (ft"/s) oxygen demand nitro[n (mg/L) 

River September June June September Station name mile 1976 1977 1977 1976 

Chattahoochee River at Atlanta __ 302.97 20.5 20.8 1,150 1,081 Chattahoochee River (Atlanta 

Intake) 

at Atlan~===================aoo~62 21 -110 -110 

Cobb Chattahooche WTF near Atlanta ______________________ 300.56 27 22 16 16 Peachtree Creek at Atlanta ______ 300.52 23 22 84 37 R. M. Clayton WTF at Atlanta __ 300.24 27 24 130 128 Proctor Creek at SR 280 at Atlanta ____________ --------297.50 22 22 7.4 6.1 Nickajack Creek at Cooper Lake 

Road 

near Mahfetl.in===============295~i3 22 22 21 13 

South Cobb Chattahoochee WTF 

near Mableton ----------------294.28 29 21 14 13 Utoy Creek WTF near Atlanta --291.60 29 23 18 19 Utoy Creek at SR 70 near 

Atlanta ----------------------291.57 23 22 16.5 10 Sweetwater Creek near Austell __ 288.58 23 22 214 130 Sweetwater Creek WTF near Austell --------------------- _288.57 

Camp Creek WTF near Atlanta __ 283.78 26 22 7.3 6 Camp Creek at Enon Road near 

Atlanta _ ---------------------283.54 24 21 19 10 Deep Creek at SR 70 near Tell __ 283.77 Anneewakee Creek at SR 166 at 23 20 21 10 

Douglasville ------------------281.47 24 21 26 17 Anneewakee Creek WTF near Douglasville _______ -----------281.46 Three-river interceptor __________ 281.45 

Pea Creek at SR 70 near Palmetto --------------------277.40 21 4 Bear Creek at SR 166 near 

Douglasville ------------------275.95 Bear Creek (SR 166) WTF near 22 20 40 11 

Douglasville _________________ -275.94 

Bear Creek at SR 70 near Rico --274.49 23 21 16.5 6 

DWa~~~~~-~~-~~~-~~~--------273.46 24 21 95 42 Wolf Creek at SR 5 near Banning _____________________ -267.34 21 21 19 13 Snake Creek near Whitesburg --261.72 22 21 52 46 Cedar Creek at SR 70 near Roscoe ----------------------261.25 22 22 30 14 Wahoo Creek at Arnco Mills ----259.85 22 22 27 2.2 Whooping Creek near Lowell ----250.87 22 22 27 23 Pink Creek near Centralhatchee 244.89 22 21 10 4 Centralhatchee Creek at US 27 near Franklin ________________ 236.5_1_ 22 22 65 26 

overall close agreement between the independently observed and the computed river concentrations supports the adoption of the BODu decay 

rate of 0.07 (at 20°C). The lowest BODu concentrations, 3.6 to 5.2 mg/L, were observed at the 

Atlanta station, and the highest, about 10 to 18 

mg/L, at SR (State Route) 139. The high BODu 

concentrations at SR 280 were due to the addition 

of 32 tons/day of BODu from point discharges. 

The computed BODu concentrations decreased 

from a maximum of 12.8 mg/L at SR 280 to 6.3 

mg/L at Franklin, or about 50 percent (fig. 10). In 

the same reach the BODu load decreased from 44 

to 34 tons/day, or about 23 percent. 

A nitrogenous rate of oxidation, k3 , of 0.19 (base 

10) was determined from observed NH4-N concentration changes in the river, with consideration of 

effects due to dilution during the June 1977 sur21 

(mg/L) (mg/) 

September June September June September June 7Q10 2000 1976 1977 1976 1977 1976 1977 

1,150 1,193 2.4 4.0 0.01 0.02 9.0 9.2 

-109 

31 76 67 12 10.4 3.0 .7 

15 3 7 .09 .12 8.0 6.7 

161 40 81 12 14.5 3.3 1.2 

1.5 21 50 6.7 2.9 3.8 4.0 

2.4 2.4 .68 .01 .04 8.4 8.5 

48 54 86 5.0 13.2 7.4 .7 44 33 27 13 14 2.4 3.1 

2 9 6 .42 .16 5.0 7.5 15 2.6 5 .05 .05 6.4 7.7 

3 

27 45 11 .02 5.8 3.1 3.8 

4 1.8 4 .01 .08 6.8 8.0 3 1.0 4 .01 .01 6.6 8.6 

4 1.6 4 .02 .02 6.9 8.8 

6 

42 

0.8 6.9 

5 1.0 4 .01 .02 8.2 9.2 

8 .5 1.8 4 .01 .01 6.6 8.4 

6 2.3 4 .00 .02 9.1 9.0 

15 1.3 4 .01 .02 8.9 8.6 

9 2.3 4 .00 .02 9.0 8.8 

7 1.3 4 .02 .06 4.6 8.2 

4 7.8 .02 5.2 8.9 4 1.5 3 .03 8.3 8.8 

1 1.8 4 .01 7.5 8.4 13 1.0 3 ~-----

------ ------

vey. The k3 selected was applied to a mass-balance 

integration of point- and nonpoint-source NH4-N 

loads, 6.8 and 0.21 tons/day, respectively in the 

Atlanta-to-Franklin reach of the river at the prevailing time of passage as shown by curve B in 

figure 11. The maximum accumulation of unoxidized NH4 -N of 6.5 tons/day occurs at RM 

288.58 and decreases to a residual of 2.2 tons/day 

at RM 235.46. The N03-N load (curve C in figure 

11) increased from 3.1 tons/day at RM 288.58 to 

7.4 tons/day at RM 235.46. 

A comparison of the observed and computed 

river NH4-N loads converted to concentrations in 

milligrams per liter is shown in figure 13. The 

overall close agreement between the independently observed and computed river concentrations supports the adoption of the NHrN decay 

rate of 0.19. The lowest NH4-N concentrations, 
>- <( 

c 

a: 

w 

0... 

(/) 

z 

0 

1-

~ 

ci 

<( 

0 

...J 

DISTANCE, IN RIVER MILES 

240 

U!t;ll1 

ate o· 

40 c: IOChert)• 0 ICaf >. 

cu ~Yen a 

u e111ana 

~ 

a: 

I 

I I 30 u. 

~ u. 

~ ~ ~ u. ~ u. ..r::. cu Q) I- (.) - ..c 0 c: ..c ~ Q) 

0 - ~ ..r::. (I) 0 u u > ~ C) f! t: ,_ Q) 

.... 0 .s .9 E! E E :; ~~ :J ::::> cu u :J ..c 

20 y 03 CJ) 

0 ~ Q) 0. ~ ~ E :§ 10 

I 

Q) cu :.c ~ cu u. ~ 8 ~ u 

I 

CJ) 

/ f! 

I 

c: 

I I 

cu 

~ 

/ 

10 

Nitrate nitrogen 

Ammonium nitrogen 

0 

0 0.5 1.0 1.5 2.0 2.5 3.0 

TIME OF PASSAGE, IN DAYS 

FIGURE 11.-Magnitude of point- and nonpoint-source BOD, ammonium nitrogen, and nitrate nitrogen loads in the Atlanta-toFranklin reach of the river during low-flow period, June 1-2, 1977. 

0.00 to 0.04 mg/L, were observed at the Atlanta 

station and the highest, 1.2 to 2.4 mg/L, at SR 280 

(RM 298. 77). The computed NH4-N concentrations decreased from 1. 7 mg/L at SR 280 to 

0.40 mg/L at Franklin. The lack of agreement 

(about 0.15 mg/L) between the observed and computed NH4-N concentrations at Bush Head Shoals 

(RM 246.93) and at Franklin may be due, in part, 

to NH4-N assimilation by extensive periphytic 

growth on the shoals in this reach of the river. 

A comparison of the independently observed 

and computed conversion of river NH4-N to 

N03-N concentrations is shown in figure 14. The 

overall close agreement indicates that the formation of N03-N was mostly due to the oxidation of 

NH4-N at a k 3 of 0.19. The lowest N03-N concentrations, 0.25 to 0.31 mg/L, were observed at the 

22 

Atlanta station, and the highest, 1.2 to 1.4 mg/L, 

at Franklin. 

An overall confirmation of the self-purification 

factors adopted (k 1 = 0.07 at 20°C andk3 = 0.19) is 

shown by the comparison of the observed and 

computed river DO concentrations in figure 15 for 

the June 1-2, 1977, intensive synoptic survey. 

The highest DO concentrations, 8.1 to 10.8 mg/L, 

were observed at the Atlanta station. Pointsource NH4-N and BODu discharges and the heat 

load from the thermal powerplants cause the observed DO concentrations to decrease to 4.4 mg/L 

just upstream of the Capps Ferry Bridge (RM 

271.19). DO concentrations less than 5.0 mg/L 

were observed in a 22-mile reach of the river from 

Fairburn (RM 281.88) to Whitesburg (RM 

259.85). The DO concentrations gradually , in-
DISTANCE, IN RIVER MILES 

300 290 280 270 260 250 240 28 I I I 'I I' I I I I I 

a: 26 r- EXPLANATION -

w 

1--

~ • Computed BODu 24 r- - en a: 0 ~ • Observed BODu w 00 

a.. N 

22 1- ~ ~ - en :::J :::J 0 

:!: 0 cc cc <( 20 r- ~ ~ - a: ~ <.0 (!) ~ en ~ en ~ 

...J 18 r- ~ -

~ :::J .:..: Q) 

0 Q) C) 

cc Q) ~ u "'0 

~ 16 1- ... ~ ~ lD - .... LL. 

ci ~ co ~ (/) 

en E Q) i= (/) z 14 1- .; :::J aJ lD 0 Cij - <( -e Q) LL. (/) 0 

:!: 'iij > (/) Q) J: • 0 a. J: ~ en w ' LL. ..c a. £ 

c 12 1- <( co :::J :::J "'0 -

• I u :J: ..c co (/) Q) 

z • . ~ :J: w :.c c: 10 r- •• (!) ~ J: 

(/) .:..: =- >- • :::J c: 

>< ' aJ E 

0 8r- 'I • LL._ 

...J ~ i • lS c: .. •- co :· 6r-+=' 

~ :/<( I 

w • f 

:I: 44t ; - u 

0 

iii 2r- -

0 I I I II II I I I I I 

0 0.5 1.0 1.5 2.0 2.5 3.0 

TIME OF PASSAGE, IN DAYS 

FIGURE 12.-Comparison of observed and computed BODu concentrations in the Atlanta-to-Franklin reach of the river during 

low-flow period, June 1-2, 1977. 

creased from 4.4 mg/Ljust upstream of the Capps 

Ferry Bridge to an observed concentration of 7.2 

1ng/L at Franklin. 

DO concentrations in the river for the June 

1-2, 1977, survey are decreased about equally by 

carbonaceous (52 percent) and nitrogeneous (48 

percent) oxygen demands. The computed effect of 

carbonaceous demands only (k 1 - 0.07 at 20°C) on 

DO concentrations is shown in figure 16, and the 

effect of nitrogenous demands only (k 3 - 0.19) is 

shown in figure 17. In the upper reach of the river 

(RM 302.97 to RM 271.19), 48percent of the carbonaceous oxygen demands an·d 58 percent of the 

nitrogenous oxygen demands are exerted, because 

the nitrogenous demands occur at a higher rate 

than do the carbonaceous demands. The computed 

minimum DO concentration exceeds 6.0 mg/L in 

figures 16 and 17. 

Average observed water temperatures in the 

Atlanta-to-Franklin reach are shown in figure 18. 

23 

The lowest average water temperature, 20.8°C, 

occurred at the Atlanta station, and the highest 

average water temperature, 27.1°C, occurred just 

downstream (RM 298. 77) from the AtkinsonMcDonough powerplants. Downstream from the 

Atkinson-McDonough plants, the lowest average 

temperature, 24.0°C, occurred at Hutcheson's 

Ferry (RM 255.66). The observed average water 

temperature at Whitesburg was 25°C and was the 

equilibrium temperature without the thermal 

discharges from the Atkinson-McDonough plants. 

The average water temperature at Franklin was 

26.TC. 

An analysis of the effect of the heat load from 

the Atkinson-McDonough plants on the DO and 

BOD regimes for the period June 1-2, 1977, indicates that the DO concentrations are about 0.2 

mg/L less with the heat load than without. With 

the heat load, 34 tons/day of BODu reached the 

lake, and without the heat load 35 tons/day of 
DISTANCE, IN RIVER MILES 

300 290 280 270 260 250 240 

3.5 I I I I I I' I I I I I 

f- EXPLANATION -

a: 0 

w • Computed NH4 as N CX) 

1- 3.0 f- N -

::i Q) en s • Observed NH4 as N ~ a: 0 

w f- a: Q) -

Q.. ~ s 

:! 0 

en a: ~ 

~ 2.5 f- (f) 

~ -

<( co ~ ~ 

(j) ::I Q) 

a: 0 Q) 

(!) r- a: c:: u 

::i ~ :; ... Q) 

...J co ~ co C) 

~ (j) Q) "'C 2.0 r- co en ~ ~ - LL. Q) 

~ > ~ Q) 

0 LL. 

z~ r- .0 lii II) <( LL. ""c:: w II) 0 

(!) • a. II) 

Q) 

0 1.5 f- a. .r:. - co a: tt u .s ~ 

!::: ::I ::I II) 

• :I: .0 "iii z f- II) 0 -

• ~ .r:. 

en :.c (f) 

<( ' ~ "'C 

1.0 f- • co - ~ Q) 

:I: ::::> • • : .r:. c:: z II) 

f- ' ::I ~ - 0 en c:: 

~ • ~ 

~ 0.5 f- LL. - <( 

co • 

c 

co =• - !! ;( 

o"'a(' I I I I I II I I I I I 

0 0.5 1.0 1.5 2.0 2.5 3.0 

TIME OF PASSAGE, IN DAYS 

FIGURE 13.-Comparison of observed and computed ammonium nitrogen concentrations in the Atlanta-to-Franklin reach of the 

river during low-flow period, June 1-2, 1977. 

BOD11 reached the lake. The difference in the 

BOD residual loads at Franklin relative to the 

heat load was about 3 percent. Therefore, the net 

effect of the Atkinson-McDonough plant heat 

loads on the DO and BOD regimes appears to be 

negligible. 

The computed DO profile from data collected 

during the low-flow period of August 31 to September 9, 1976, (table 13) is shown in figure 19. A 

0.07 k 1 and a 0.19 k 3 (the same as those in June 

1977) were used in the DO computations. The 

flows at the Atlanta station and tributaries and 

the nonpoint-source BODu and point-source BODu 

and NH4-N loads (21.3 and 5.51 tons/day) were 

less in September 1976 than in June 1977. The 

lesser flows and loads in September 1976 resulted 

in a DO profile similar to that observed in June 

1977. 

24 

The close agreement between the computed and 

observed DO profiles permit projection of results 

from wastewater management alternatives. 

ECONOMIC CONSIDERATIONS OF WASTEWATER 

MANAGEMENT ALTERNATIVES 

Schefter and Hirsch (1979) evaluated the cost of 

four alternatives for maintaining a minimum DO 

concentration of 3, 4, or 5 mg/L in the river for the 

years 1980, 1990, and 2000. All wastewater from 

the WTF's was assumed to receive at least secondary treatment (45 mg!L BODu, 15 mg!L NH4-N). 

The alternatives evaluated were: 

1. The least-cost combination of nitrification (27 

mg/L BOD11 , 3 mg/L NH4-N) of a percentage 

of the total wastewater discharge and 
DISTANCE, IN RIVER MILES 

300 290 280 270 260 250 240 

1.4 I I I I I II I I I I I • 

1.3 ~ :; -

• 

1.2 r I 

a: ~ .. - w 1/) 1- .E: 

::J ~ iii 32 1.1 1- ... 0 c: - .r::. a: ~ • (/) 

w u.. 

a.. "0 

1.0 r I ctl <0 ~ Q) - C/) ~ c: • ::I: 

::!: Q) :; i ~ ~ .r::. 

~ s -e Q) :I 1/) 

0.9 1- • .0 :I - a: 0 "iii .: u.. ! co (!) 0) rx: 1/) 

~ u.. :! ::J ! Q) c :c ...J 0.8 r Q) ctl ~ 

0) 0 ~ -

~ s en • "0 1/) 

Q) 

~ Q) 

0 Q) .r::. 

rx: :: u £ ~ 0.7 1- ,, ~ :I - ! • ... ::I: ctl Q) z~ ctl Q) 

en co u.. 

w 0 II) 

(!) 0.6 r (X) Q) a. - N > a. 0 ! 0 ctl 

a: -i .0 u :I <( 1- 0.5 1- 0 ·i -

z rx: 

C/) ! • 0.4 r.S ctl - ~ c: en ctl 

w 

~ 0.3 ~/~ ' -

a: • i.. EXPLANATION 

1-

z 0.2 r • Computed N03 as N -

• Observed N03 as N 

0.11- -

0 I I I I I II I I I I I 

0 0.5 1.0 1.5 2.0 2.5 3.0 

TIME OF PASSAGE, IN DAYS 

FIGURE 14.-Comparison of observed and computed nitrate nitrogen concentrations in the Atlanta-to-Franklin reach of the 

river during low-flow period, June 1-2, 1977. 

modification of the present hydropower generation pattern at Buford Dam. 

2. Nitrification of some percentage of the total 

wastewater discharge without modifying 

power generation patterns at Buford Dam. 

3. Nitrification of the total wastewater discharge 

without modifying present power generation 

patterns at Buford Dam. 

4. The least-cost combination of nitrification of 

some percentage of total wastewater discharge without modifying the present power 

generation pattern at Buford Dam, and assuming the storage capacity of Morgan Falls 

reservoir is increased and a reregulation 

structure is built downstream from Buford 

Dam. 

Computations of minimum DO concentrations 

are based on the following conditions: (1) point25 

source discharges from Atlanta to Franklin of 

250, 314, and 370 ft 3/s in the years 1980, 1990, and 

2000, respectively, (2) point-source discharges 

containing concentrations of 45 and 27 mg/L 

BOD11 and 15 and 3 mg/L NH.rN, (3) tributary 

inflows of 93 ft3/s from Atlanta to Franklin (lowest consecutive 7-day mean flow that occurs once 

in 10 years) and (4) minimum sustained 

streamflow at the Atlanta station ranging from 

860 to 1,800 ft 3/s. The computed minimum DO for 

various combinations of wastewater treatment 

(expressed in percentage of total wastewater 

treatment discharge receiving nitrification) and 

flow at the Atlanta station are summarized in 

figure 20. To attain a minimum DO concentration 

of 4.0 mg/L in the Atlanta-to-Franklin reach with 

a streamflow of 1,500 ft3/s at the Atlanta station 

would require nitification of22 percent (55 ft 3/s) of 
DISTANCE, IN RIVER MILES 

300 290 280 270 260 250 240 14 I I I II II I I I I I 

13 1- -

12 r-.S 0 - a: c: co co w N 

..... 11 ~ .e ::::i :;, - 0 (j) 

a: a:: w ~ 10 r- .e a.. co .e - (/) U5 :;, .!: 

gf 0 32 :2 a:: (/) 

co tO c: 

< ' .e co ~ 0 !!!- a: .:i co .... ..c: LL 

~ :· : U5 ~ Q) ~ en LL 

::::i 8.!... ~ ~ Q) :;, '0 

-~ - 0 Q) C) (/) .0 co ...J e! :'2 C: (/) 

~ :&: a:: .e Q) 

.e u IIi 0 J: c: Cll :c 7- • ~ :; ... ~ Q) $: ..c: .\ - ~ co ..c: (/) 

::: -e Q) 

~ :;, 

co Q) co ., z 'iii LL :;, .. LL Q) J: 

w 6-

~~ > 8. ·i. . - 0 (!) .0 a. ::;: l > • ,!. <t co .. l!i X Sr- u I 

0 

T= 

- ·:::' i!~~ .. Iii; Cl ·:, w 4r-

> - ...J 

0 

(/) 3r- - (/) EXPLANATION c 

2r- • Computed DO -

· Observed DO 

1 r- -

0 I I j J! II l I I I I 

0 0.5 1.0 1.5 2.0 2.5 3.0 

TIME OF PASSAGE, IN DAYS 

FIGURE 15.-Comparison of observed and computed DO concentrations in the Atlanta-to-Franklin reach of the river during 

low-flow period, June 1-2, 1977. 

the wastewater discharge in 1980, 36 percent (113 

ft3

/s) in 1990, and 48 percent (179 ft3/s) in the year 

2000. 

COST OF WASTEWATER TREATMENT 

The additional cost of nitrification for each of 

the WTF's in the Atlanta-to-Franklin reach was 

estimated using information provided in the Atlanta Regional Commission's wastewater management plans and Giffels and others (1977). 

Annual operating costs attributable to upgrading the facilities were added to annualized capital 

cost to determine the total annual cost of nitrification. The estimated cost and flow for each facility 

are shown in table 14. Annual costs were related 

to the percentage of the total point-source load 

receiving nitrification in the years 1980, 1990, 

26 

and 2000 (fig. 21). The figure shows that in 1980, 

if 50 percent of the wastewater was nitrified 

rather than treated at secondary levels, the additional cost would be $1.6 million per year. The 

additional cost for 1990 would be $2.0 million per 

year, and for the year 2000, $2.5 million per year. 

COST OF CHANGING RELEASE PATTERN FROM 

BUFORD DAM 

The U.S. Army Corps of Engineers (1975) in a 

study of the Buford Dam/Lake Sidney Lanier 

project estimated that 7 4 percent of the average 

annual benefits consist of recreation benefits, 17 

percent consist of benefits from hydroelectric 

power, and the remainder, 9 percent, are from 

flood control, navigation (in the Apalachicola 

Waterway), water supply (for the Atlant~ Met-
DISTANCE, IN RIVER MILES 

300 290 280 270 260 250 240 14 

13 

12 0 a: CIO 

w N 

!:: 11 CD 

...J s 

0 en a: Cl: 

w ~ s Ul Q.. 10 ctl s co (ii ~ CD ~ .!: (/) ::I ~ 0) 0 0 .... CD '"0 ~ ..r:. 32 ~ 9 Cl: CD ~ ~ Ll.. en t:: 

<( ! s u Ul '"0 ctl 

a: :I• ... ~ 1::: ~ m Lt 

(!) s 0 ctl 0 ::I CD 

i en Cl: E CD CD Ul .0 ::c ::i 8 a:l Ul s ::I Ll.. CD s ..r:. ...J t. ctl -e CD Ul ..r:. Ul ·! ~ (;) > a. £ :.c ::I 

"iii 0 a. ::I ~ a:l 

7 ::~ • Ll.. .0 ctl ::c 

~ • <( u • .: ;;: 

• • • .ii z • • ·.· •: 

w 6 1iu ·:. 

(!) :!!: ==•: 

> : '! .. ··~ =1· li! 

X e:· 5 0 !i!il ·'· iJf :: 

0 im= : 

w 4 

> ...J 

0 

(J) 3 (/) EXPLANATION 0 

2 • Computed DO 

Observed DO 

0 

0 0.5 1.0 1.5 2.0 2.5 3.0 

TIME OF PASSAGE, IN DAYS 

FIGURE 16.-DO concentrations observed and DO concentration profile due only to carbonaceous oxygen demands in the 

Atlanta-to-Franklin reach of the river during low-flow period, June 1-2, 1977. 

TABLE 14.-Average daily flow of waste treatment plants discharging to the Chattahoochee River between Atlanta and Whitesburg 

and the annualized cost of converting the plants from secondary to advanced levels of treatment (nitrification) 

Plant Name River 

mile 

Cobb-Chattahoochee ______________ 300.56 

R. M. Clayton ____________________ 300.24 

South Cobb ______________________ 294. 78 

Utoy Creek ______________________ 291.60 

Sweetwater Creek ________________ 288.57 

Camp Creek ----------------------283.78 

Anneewakee Creek ________________ 281.46 

Regional Interceptor ______________ 281.45 

BearCreek ______________________ 274.48 

[Costs in first quarter 1976 dollars] 

1980 

Average Annual Average flow cost flow (ft3/s) ($1,000) (ft"/s) 

24.0 458.40 28.9 

131.1 1,704.19 150.0 

38.1 694.43 51.1 

42.0 722.43 46.0 

2.9 

15.0 359.82 22.0 

6.0 

7.0 

27 

1990 2000 

Annual Average Annual 

cost flow cost ($1,000) <ft3

/s) ($1,000) 

518.27 30.7 538.85 

1,932.45 161.3 2,069.03 

851.60 48.5 819.79 

771.07 44.0 746.75 

147.69 2.6 143.95 

444.02 27.2 507.63 

193.84 6.0 193.84 

42.4 726.14 

207.34 7.7 216.69 
DISTANCE, IN RIVER MILES 

300 290 280 270 260 250 240 14 I I I II 11 l l I I I 

13 t- -

12 t-.!!! 0 - a: c: 00 IU N w 

1- 11 ~ .e 

:::J ::::J - 0 0> 

a: a: 

w ~ .e (/) 

a.. 10 t- .!!! CD Iii - 5 CD ~ 0 (J) .5 CD .c en -~ 0 CD .ll<: C) l5 (J) 32 :1! a: (I) :Q .... (I) LL c: 91-;; m '"0 <( I .e (I) 0 (/) 

~ IU E- a: i :i! IU 5 i::: CD LL 

(!) .. 00 0 .... ~ 0 ::::J J: 

sr!- IU l5 (/) .0 

:::J ~ a: c: (I) (I) (/) .c :- $ :; m LL .c .e (/) 

::! ::::J • =.· (I) (/) u :c m :1! ~ -e > 0. 5 (J) ·a; 0 0. J: 3: 7t- "'I lL .0 IU • .i - ~ r:. 

.,. <( u • • • z • • • 11 

6t- w if!! i. . - (!) ·" iin :i• ··=· > I .. T f.-. 

X 5t- u• 

0 1fi!\ - .,. !!. i: 

0 ~i:~ ·:if : 

w 4r-- - > ...J 

0 

en 3t- - en EXPLANATION 0 

2t- • Computed DO -

· Observed DO 

1 t- -

0 I I I II I I I I I I I 

0 0.5 1.0 1.5 2.0 2.5 3.0 

TIME OF PASSAGE, IN DAYS 

FIGURE 17.-DO concentrations observed and DO concentration profile due only to nitrogenous oxygen demands in the 

Atlanta-to-Franklin reach of the river during low-flow period, June 1-2, 1977. 

ropolitan Area), and low-flow water-quality 

maintenance (for the Chattahoochee River from 

Atlanta to West Point Lake). Hydroelectric power 

benefits may be subdivided into three types: benefits of energy production in peak demand hours, 

benefits of energy production in nonpeak demand 

hours, and dependable peaking capacity benefits. 

The changes in the pattern of release for Buford 

Dam considered by Schefter and Hirsch (1979) result in almost no change in benefits except for 

dependable peak hydropower capacity. To sustain 

higher minimum flows at the Atlanta station, the 

release of water during peak periods of electricity 

demands must be decreased in low-flow years, 

causing a corresponding decrease in the dependable peak power capacity. It is assumed that the 

dependable peaking capacity lost at Buford Dam 

could be replaced by the construction of a facility 

comparable in cost ($23.34 kW/yr) to Georgia 

Power Company's Rocky Mountain pump-storage 

project. The annual benefits foregone are the 

losses in dependable peaking capacity times this 

$23.34 kW/yr. 

Figure 22 shows the relationship between flow 

at the Atlanta station and the annual benefits 

foregone at Buford Dam for the years 1980, 1990, 

and 2000. The differences in flow at the Atlanta 

station are due to increases in water-supply withdrawals from Lake Sidney Lanier and from the 

Chattahoochee River from an annual average of 

about 170 ft3/s in 1980, 240 ft3/s in 1990, to 610 

ft3/s in 2000. 

FIGURE 19.-Comparison of observed and computed DO concentrations in the Atlanta-to-Franklin reach of the river during ..,.. 

low-flow period, August 31 to September 9, 1976. 

28 
DISTANCE, IN RIVER MILES 

300 290 280 270 260 250 240 

30 

0 

co en Ill N r:: ~ (ij 

!!a co 0 N 

::J !!a ~ N" .r::. ui 0 ::J en CJ) 

C/) a: 0 !!a !!a "0 ::) 

::::> 28 !!a a: ::J ::J r:: ca 

U5 0 0 CD 

.l!! a: Ea:: N :I: ...J CJ) 

w ::J CD .r::. ..c- Ill 

u ._ ca ::J 

·a; U5 Ill 

C/) u..- w 

w 26 a: 

(!) 

w 

c 

~ 

w' 

a: 24 ::::> 

1-

<( 

a: 

w 

D.. 

~ 

w 22 .l!! 1- 1: 

~ _JA:stimated 

<( c:Y --

20 

0 0.5 1.0 1.5 2.0 2.5 3.0 

TIME OF PASSAGE, IN DAYS 

FIGURE lB.-Temperature of river water in the Atlanta-to-Franklin reach of the river during low-flow period, June 1-2, 1977. 

DISTANCE, IN RIVER MILES 

10 300 290 280 270 260 250 240 

I -r l I I I I I I II I I 

jo 

1-

w 

a: ~ E 

-

:::J ca 

81-~ a: • -

w 0 D.. co f N 

C/) I- CD 

~ s en 0 <( a: ~ a: • (!) 6- !!a !!a 

:::J .l!! ::J ~ :. 

~ CJ) 0 

a: • .:. • • Ill 

~ !!a co (ij 

ca ~ ~ 0 

~ U5 s E • ~ .r::. 

::J ::J CJ) 

CD ..c z 0 -e CD u.. Ill "0 

a: ·a; Cl !!a ca w 41- Ill CD 

(!) !!a u.. "0 i:::: :i: :I: 

~ 0 > .l!! Ill ~ .r::. 

X CJ) 

~ CD Ill 

.r::. ::J 

0 .s Ill 

f- CD 

c u.. ::J 

w Ill :I: 

> a. 

a. ...J ca EXPLANATION 

0 21- u C/) • Computed DO C/) 

•• 

-

-

c • Observed DO 

0 I I I I I I I I I d I I 

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 

TIME OF PASSAGE, IN DAYS 

29 
1800 

1600 

1400 

1200 

1000 

800 

c 0 

z 

0 

u 

w 1800 en 

a: 

w 

a.. 1600 

1-

w 

w 

LL 1400 

u 

iii 

;:) 

u 1200 

~ 

~ 1000 

0 

_. 

LL 

~ 

<( 

w 

a: 

1-

en 

1800 

20 40 60 80 

20 40 60 80 

~ ~ 60 80 

PERCENTAGE OF TOTAL WASTEWATER DISCHARGE 

RECEIVING ADVANCED LEVEL OF TREATMENT 

100 

1990 

100 

1980 

100 

FIGURE 20.-Relationship of minimum DO concentration to streamflow at Atlanta station and percentage of 

total wastewater discharge nitrified for years 1980, 1990, and 2000. 

The maximum sustainable flow at the Atlanta 

station after water supply demands are met is 

1,670 ft3/s in 1980, 1,600 ft3/s in 1990, and 1,230 

30 

ft3/s in 2000. Benefits foregone do not decrease for 

flow at the Atlanta station less than 1,380 ft3

/s in 

1980, 1,290 ft3/s in 1990, and 870 ft3/s in 2000. 
ANNUAL COST OF CONVERTING 

FROM SECONDARY TREATMENT TO NITRIFICATION, 

IN MILLION DOLLARS PER YEAR 

"'tJ N w ~ C11 

m 

:J:J 

n 

m 

z 

);! N 

0 

G) 

m 

0 

., ~ :E 

)> 

CJ) 

-i 

m ~ :E 

~ m 

:J:J 

z ~ 

~ :J:J 

:;; 

iii 0 0 0 

FIGURE 21.-Relationship of annual cost of converting 

from secondary treatment to nitrification to percentage 

of total waste discharge nitrified for years 1980, 1990, 

and 2000. 

STREAMFLOW AT ATLANTA STATION, 

IN CUBIC FEET PER SECOND 

0) 

FIGURE 22.-Relationship of average annual benefits 

foregone at Buford Dam to streamflow at Atlanta station 

for years 1980, 1990, and 2000. 

COST OF REREGULATION OF CHATTAHOOCHEE 

RIVERFWWS 

A minimum flow of about 1,600 ft3/s at the Atlanta station could be maintained, and peak 

power and water-supply demands satisfied, at 

least through 1990, by constructing a reregulation structure with a water storage volume of 

8,400 acre-ft just downstream of Buford Dam and 

increasing the capacity of Morgan Falls reservoir, 

31 

by dredging, to a storage volume of 8,500 acre-ft. 

According to the U.S. Army Corps of Engineers, 

Lake Sidney Lanier restudy (1975), the capital 

cost of the reregulation structure would be $11.5 

million; operation and maintenance costs would 

be $65,800 per year. Using a discount rate of 10 

percent and a life of 100 years, the annualized 

cost of the reregulation structure is $1.2 million. 

The Corps of Engineers reports that the initial 

cost of dredging Morgan Falls reservoir would be 

$1.6 million and the annual maintenance cost 

$15,000 per year. Using a 10-percent discount 

rate and a 100-year life, the annualized cost of 

increasing the storage capacity of Morgan Falls 

Reservoir is $180,000 per year. Thus, the combined annual cost of constructing and operating 

the reregulation structure and Morgan Falls reservoir would be $1.4 million per year. 

COST OF WASTEWATER MANAGEMENT 

ALTERNATIVES 

Assuming a minimum DO concentration of 5 

mg/L for the year 1990, the least costly plan 

would be: nitrification of 63 percent of the total 

wastewater flow and maintenance of a minimum 

flow of 1,600 ft3/s at the Atlanta station. The additional treatment cost is estimated to be $2.72 

million per year, and the benefits foregone due to 

the loss of dependable peaking capacity are estimated to be $0.75 million per year. The total cost 

(in benefits foregone plus additional treatment 

cost) is estimated to be $3.4 7 million per year (table 15, alternative 1). 

Without modification of the Buford Dam release pattern, about 92 percent of the wastewater 

discharge would have to be nitrified in 1990. The 

estimated cost of the additional treatment would 

be $4.30 million per year, but no dependable 

peaking capacity benefits would be foregone (table 15, alternative 2). 

The additional cost for nitrification of the total 

wastewater discharge in 1990 would be $5.05 

million per year, or $1.59' million per year more 

than the least-cost plan (table 15, alternative 3). 

The least-cost plan with Morgan Falls reservoir 

dredged and construction of a reregulation structure would be $4.23 million per year. This cost 

would include $2.72 million per year for additional treatment cost, $0.10 million per year 

dependrble peaking capacity benefits foregone, 
TABLE 15.-Summary of economic considerations of wastewater management alternatives for years 1980, 1990, and 2000 

Minimum dissolved oxygen (mg/L) 

Alternative 3 4 5 3 4 5 3 4 5 

1980 1990 2000 

1. Treating a proportion of total waste discharge at advanced 

level and modification of present Buford Dam re- lease pattern: 

Minimum streamflow at Atlanta station in cubic feet 

per second-------------------------------------- 1,380 1,670 1,380 1,430 1,600 1,600 870 870 870 

Proportion of waste nitrified in percent ______________ 0 24 63 52 70 90 

Cost: 

Additional cost for nitrification in million dollars per year ____________________________________________ 

Dependable peaking capacity benefits foregone in million dollars per year ----------------------------

Total 

2. Nitrifying a p~o~rti~~- oY totcif --;aste -di-scharge- -~i thout 

modification of present Buford Dam release pattern: 

Minimum streamflow at Atlanta station in cubic feet 

per second--------------------------------------

Proportion of waste nitrified in percent_ _____________ 

Cost: 

Additional cost for nitrification in million dollars per year ____________________________________________ 

Dependable peaking capacity benefits foregone in 

million dollars per year--------------------------

Total 

3. Nitrifying tot~l-:;~~~di~~h~;.g~-~-ith~~t-~~ifl~~ti~~-~f--

plant Buford Dam release pattern: 

Minimum streamflow at Atlanta station in cubic feet 

per second ______________________________________ 

Proportion of waste nitrified in percent ______________ 

Cost: 

Additional cost for nitrification in million dollars per 

year ___ ~----------------------------------------

Dependable peaking capacity benefits foregone in 

million dollars per year--------------------------

Total 

4. Nitrifying a pr~po-rti~~~f~t-;;1-~~~t~-di~~h~-rge-~~~f&~g~ 

ing of Morgan Falls reservoir and constructing a re- regulation without modification of present Buford 

Dam release pattern: 

Minimum streamflow at Atlanta station in cubic feet 

per second--------------------------------------

Proportion of waste nitrified in percent_ _____________ 

Cost: 

Additional cost for nitrification in million dollars per year ____________________________________________ 

Dependable peaking capacity benefits foregone in 

million dollars per year __________________________ 

Cost of dredging Morgan Falls and construction of re- regulation station ------------------------------ Total ------------------------------------------

and $1.4 million per year for construction and operation of the facilities (table 15, alternative 4). 

The data in table 15 summarize the relative 

cost of various alternatives. The data indicate 

that the least-cost plans for 1980 and 1990 require a minimum flow at the Atlanta station of 

about 1,600 ft3/s. For the year 2000, however, at 

least 92 percent of the total wastewater discharge 

would require nitrification, because a minimum 

flow greater than about 1,230 ft3/s could not be 

maintained at the Atlanta station if water-supply 

demands are met during drought conditions similar to those in 1954-56. 

0 0 62 

0.00 0.00 2.03 0.0 1.08 2.72 2.58 3.76 5.10 

.00 .71 .00 .34 .75 .75 .00 .00 .00 

.00 .71 1.62 .34 1.83 3.47 2.50 3.74 5.10 

860 860 860 860 860 860 860 860 860 

39 59 84 52 72 92 52 70 90 

1.35 1.91 3.12 2.10 3.20 4.30 2.58 3.76 5.10 

.00 .00 .00 .00 .00 .00 .00 .00 .00 

1.35 1.91 3.12 2.10 3.20 4.30 2.58 3.76 5.10 

860 860 860 860 860 860 860 860 860 

100 100 100 100 100 100 100 100 100 

3.95 3.95 3.95 5.05 5.05 5.05 5.95 5.95 5.95 

.00 .00 .00 .00 .00 .00 .00 .00 .00 

3.95 3.95 3.95 5.05 5.05 5.05 5.95 5.95 5.95 

1,640 1,640 1,640 1,560 1,600 1,600 1,230 1,230 1,230 

0 0 46 0 24 63 36 58 82 

0.00 0.00 1.54 0.00 1.09 2.72 1.77 2.92 4.50 

-.01 .20 -.01 -.01 .11 .11 .07 .07 .07 

1.40 1.40 1.40 1.40 1.40 1.40 1.40 1.40 1.40 

1.39 1.60 2.93 1.39 2.60 4.23 3.24 4.39 5.97 

BIOLOGICAL ASSESSMENT 

Studies were conducted to (1) assess the amount 

and rate of nitrification in the Atlanta-toFranklin reach of the Chattahoochee River, (2) 

relate the nutrient concentration to AGP (algal 

growth potential), and (3) determine the effect of 

nutrient concentration as measured by AGP on 

algal growth in the West Point Lake. 

NITRIFICATION 

Nitrification can be an important factor affecting the DO balance in streams. DO concentration 

32 
decreases in the river were due to a combination 

of nitrogenous and carbonaceous oxygen demands. Nitrogenous demands (nitrification) 

caused approximately 50 percent of the DO decreases in the Atlanta-to-Franklin reach of the 

river. Figure 23 shows the decreases in DO concentration resulting from nitrification and the 

total decreases in DO concentration during the 

low-flow period of June 1-2, 1977. 

Nitrification, oxidation of NH4-N to N03-N, 

proceeds in two steps catalyzed by the 

chemoautotrophic bacteria, Nitrosomonas and 

Nitrobacter (Alexander, 1965): 

NH4 + 1lh 0 2 Nitrosomonas N02- + 2H+ + H20 

N02_ + lh 02 Nitrobacter N03-

Studies by Ehlke (1978) indicate that the concentration of N itrobacter in the benthic sediment, 

shown in figure 24, ranged from about 102 to 103/g 

in the reach from Atlanta to Franklin. Nitrobacter was less abundant in the water column than in 

the benthic sediment throughout the reach, generally less than 10 bacteria/mL. Compared with 

findings in studies elsewhere (Tuffey and others, 

1974; Curtis and others, 1975), the concentration 

of Nitrobacter and Nitrosomonas in the Chattahoochee River was very low. The concentration 

of Nitrosomonas in Chattahoochee River water 

and benthic sediment (fig. 25) was greater than 

corresponding N itrobacter concentrations. 

The observed NHrN, N02-N, and N03-N concentrations in the Chattahoochee River from RM 

302.97 to RM 235.46 are shown in figure 26. The 

concentrations ofNH4-N, N02-N, and N03-N were 

lowest near Atlanta (RM 302.97), which is 

upstream from the Metropolitan Atlanta WTF's. 

The NH4-N concentration was maximum at RM 

298.99, which is just downstream of the major 

WTF's. Oxidation ofNH4-N to N03-N by bacterial 

2.0~~--------~--------~~--------~--------~--------,---------.---------, 

a: 

w 

1-

:::::i 

a: 

w 

a.. 

(/) 

~ 1.5 

<( 

a: 

C) 

:::::i 

__. 

~ 

~ 

z 

w 

~ 1.0 

X 

0 

0 

w 

> __. 

0 

(/) 

(/) 

c 

~ 0.5 

w 

(/) 

<( 

w 

a: 

u 

w 

0 

0 

300 290 280 

EXPLANATION D Total decrease in dissolved oxygen 

~ Decrease in dissolved oxygen because 

of nitrification 

270 260 250 

DISTANCE, IN RIVER MILES 

240 230 

FIGURE 23.-Comparison of decreases in DO resulting from nitrification to total decrease in DO in the Atlanta-to-Franklin 

reach during low-flow period, June 1-2, 1977. 

33 
303 299 286 282 276 271 266 260 247 235 

DISTANCE ABOVE MOUTH, IN RIVER MILES 

FIGURE 24.-Nitrobacter population in Chattahoochee River water and benthic sediment during June 1-2, 1977 . 

• , ................ I -............._ 

I -............._ / '> -----•------

• I '-..•/ Water column •--- --------• 

I 

I 

I 

I 

I 

I 

I 

I 

• 

303 299 286 282 276 271 266 260 247 235 

DISTANCE ABOVE MOUTH, IN RIVER MILES 

FIGURE 25.-Nitrosomonas population in Chattahoochee River water and benthic sediment during June 1-2, 1977. 

nitification occurred nearly linearly from RM 

298.99 to RM 235.46. The maximum concentration ofN03-N, which is the end product ofnitification, occurred near the downstream end of the 

study reach. 

The concentration of NH4-N decreased at al34 

most a constant rate of 0.02 mg/Lih (milligrams 

per liter per hour) during June 1-2, 1977, from 

RM 298.77 to RM 235.46, on the basis of a 

traveltime of about 65 hand a change in concentration of NH4-N from 1.8 to 0.2 mg/L (fig. 22). 

The concentrations of N03-N increased at al-
TIME OF TRAVEL, IN HOURS 

0 10 20 30 40 50 60 

2.0 r--,.-------..-------r-------r------..----------r---------,----, 0.20 

1.8 

z 

8 1.6 

z 

ca: 

z~ 1.4 

<C::i 

.... 

I ...... 

I ........... 

I ......... 

I I '~. ', I ,, 

: .......... 

a: 

~ 0.18 ::i 

a: 

w 

0.16 ll.. 

(/) 

0.14 

~ <( 

a: 

(!) 

Za: 

~w 1.2 J:ll.. 

ZCI) 

LL ~ 1.0 

0<( 

I ...... ~. 

I ~--._ ',, ~OJ •------•uo.12 : ,I ·-......... 

I .' ......... ', ,'~. 

: I '· ............ _.~-:_·"'· >• .... 

::i 

....I 

:i 

~ 0.10 -

a: 1 I -~· '· ........ ~ N 

Z(!) 

Q ::i 0.8 

I • ..----.... ... 

1

.' ./' ......... _ ;--.... -·-· .,. _ N02-N ·'--.---·-·-· 

0 

0.08 z 

I I ~· ........ ~~ I • ..., 

LL 

0 !z ~ 0.6 1 I / ')-, 

I j ~· NH4-N ',, 

0.06 z w 0 

u 

~ 0.4 

u 

I • ~ ' : . ./. ... ...... 0.04 ~ I / ,.,. "'e~ .. _ ~· .......... _ a: 

1-

z 

w 0.2 I / --...... 0.02 u 

z 

0 

u 

I • 

1.' 

o~•~-~--L------L----L----L-~--~---~L-------~-----~~o 303 299 295 286 282 276 271 266 260 247 235 

DISTANCE ABOVE MOUTH, IN RIVER MILES 

FIGURE 26.-Mean concentrations of ammonium, nitrite, and nitrate as nitrogen in the Chattahoochee River during 

June 1-2, 1977. 

most a constant rate of 0.02 mg/Lih during the 

period of June 1-2, 1977, from RM 302.97 to RM 

246.93. The increase in NH4-N concentration was 

approximately equal to the decrease in the N03-N 

concentration during the period of June 1-2, 

1977. 

Generally, the greater concentration of nitrifying bacteria in river-bed sediments compared 

with that in the water column has led many investigators to conclude that most nitrifying 

bacteria activity probably occurs in benthic sediments, not in the water column (Tuffey and 

others, 1974; Matulewich and Finstein, 1978). 

All sampling for nitrifying bacteria was done 

when the flow of the Chattahoochee River was 

near 1,150 ft3/s and the mean depth from RM 

302.97 to RM 258.63 was about 4.7 ft. Using the 

data of figures 24 and 25, the relative concentrations of Nitrosomonas and Nitrobacter can be 

calculated in a 4. 7 ft water column and 0.4 in 

benthic sediment column. Averaging the data, 53 

percent of the N itrosomonas are calculated to be 

in the water column, and 4 7 percent in the top 0.4 

in of benthic sediment. Similarly, 72 percent of 

35 

theNitrobacter were present in the water column, 

and 28 percent in the benthic sediment. This indicates that, during the study period, most nitrifying bacterial activity occurred in the water column,· not in the benthic sediment. 

PHYTOPLANKTON 

Concentrations of phytoplankton (diatoms, 

green algae, and blue-green algae) were generally 

higher downstream from Atlanta than upstream 

of Atlanta (Lium and others, 1978). Concentrations of phytoplankton were higher in Lake 

Sidney Lanier and West Point Lake than in the 

river and tributaries, with maximum concentrations occurring in West Point Lake 

downstream from Franklin. 

Figure 27 shows a comparison of phytoplankton 

concentrations from the headwaters of the Chattahoochee River to the West Point Dam during 

August 1976. The highest concentration (mostly 

blue-green algae) occurred in West Point Lake. 

The lowest concentration occurred near Norcross. 

Figures 28, 29, and 30 show the monthly variation in average concentrations of the various 
100,000 

a: 

w 

I-

::J 

::J 

...J 

~ 

a: 

w 

0.. 

CJ) 

...J 

...J 

w 

u 10,000 

~ 

z' 

0 

I-

~ 

z 

<{ 

...J 

0.. 

0 

~ ::z:: 

0.. 

1000 

100 

X 

co~ :=a: 

E~ c...: 

u~ 

EXPLANATION 

X Total count 

• Blue-green algae 

.A Green algae 

• Diatoms 

RM River mile 

X 

.... 

Q) Cl)~ 

·c:::::- ~a: 

~g~ .......... 

~ ...... > a.a: Oci 

~E~ ZM M "010. 

u;-o~ 

cu(QM 

~-co 

...J 

co~ 1:~ El~ 1:~ Q)~ "E~ Q) 

.... a: "-Cl: :=a: g»a: ~-

c,..... :::::Jcn _Ea: ~co roo .Ea: ~g~ ~en ~I": ~~ 0N 1: v .......... t;O.Cl: <iN ca..- ~I": ~ tri (.!) ci 0 . 0 LL. 00 :E(O LL.(V') CON ..OM ·c;E ~ M N 3:N N ...JN ..c..- D.. co . <{N .,_."0 0 rn .... N CD co 3:-

FIGURE 27.-Concentration of phytoplankton by river mile for August 1976. 

phytoplankton genera in Lake Sidney Lanier and 

West Point Lake. Average concentrations of 

blue-green (fig. 28) and green algae (fig. 29) were 

highest in West Point Lake. In the spring, 

monthly concentrations of diatoms (fig. 30) were 

highest at Lake Sidney Lanier. The spring diatom 

36 

increase as shown in figure 30 did not occur in 

West Point Lake. The blue-green algae were dominant in both lakes, and concentrations were 

highest during the summer months. Diatom concentrations generally exceeded the green algae 

concentrations in both lakes. 
~2~.000.------.------.------.------,------,,------.------.------.------~------.-----~ 

w 

1-

::::i 

::::i 

...J 

~ 200,000 

~ 

w 

a.. 

~ 150,000 ...J 

w 

u 

~ 

~ 100,000 

C) 

...J 

<( 

z 

w 

w 

~ 

C) 

w 

::::> 

...J 

m 

OCT. NOV. 

(1975) 

DEC. 

I 

JAN. 

EXPLANATION 

----•---- Lake Sidney Lanier 

--)(-- West Point Lake 

---·--·---------- No data 

FEB. MAR. APR. MAY 

(1976) 

JUNE JULY AUG. SEPT. 

FIGURE 28.-Average concentration of blue-green algae by month in Lake Sidney Lanier and West Point Lake. 

u.i 

<( 3000 C) 

...J 

<( 

EXPLANATION 

--•-- Lake Sidney Lanier 

--X--. West Point Lake 

-------------·-·· No data 

-x 

JAN. 

;\ 

.. ~, 

.. ··· \ .. ··· \ .. ··· \ ..... \ 

.. ··· \ ... ·· \ 

/ \ ...... \ 

.......... 

.... ··• 

JULY AUG. SEPT. 

FIGURE 29.-Average concentration of green algae by month in Lake Sidney Lanier and West Point Lake. 

37 
a: 

w 

1-

:J 

:J 

..J 

~ 

a: 

w 

D.. 

~ ..J 

w 

u 

~ 

u) 

~ 

~ 0 

EXPLANATION 

---•--- Lake Sidney Lanier 

--X-- West Point Lake 

••••••••••·•••• No data 

....... ·············· ................ 

JAN. FEB. 

...... 

MAR. APR. MAY 

(1976) 

JUNE JULY AUG. SEPT. 

FIGURE 30.-Average concentration of diatoms by month in Lake Sidney Lanier and West Point Lake. 

Figure 31 shows mean annual concentrations of 

total phytoplankton, dissolved POrP (orthophosphate as phosphorus), and N02 + N03-N (nitrite 

plus nitrate as nitrogen) from the upper reaches 

of the Chattahoochee River to the West Point 

Dam. Phytoplankton concentrations upstream of 

Lake Sidney Lanier were less than 1,000 cells/ 

mL, and in Lake Sidney Lanier they were about 

10,000 cells/mL. Concentrations downstream 

from Lake Sidney Lanier to the upstream end of 

West Point Lake at Franklin were less than 4,000 

cells/mL. Maximum concentrations in West Point 

Lake were about 90,000 cells/mL. 

The dissolved P04 -P and N02 + N03 concentrations were highest in the river reaches and the 

upper parts of the two lakes and lowest in the dam 

pools of both lakes. The high N02 + N03-N concentrations downstream from Atlanta were 

primarily a result of nitrification of treated sewage effluent by the Nitrosomonas and Nitrobacter 

bacteria (Ehlke, 1978). 

ALGAL GROWTH POTENTIAL 

Oswald and Golueke (1966) first used the term 

((algal growth potential" (AGP) and defined it as 

((the dry weight of algae which will grow in a 

38 

given water sample in the laboratory when no 

factor other than dissolved nutrients in the sample is limiting to growth." 

Algal assays are sometimes utilized to determine the effects of nutrients from municipal, industrial, or agricultural wastewater effluents on 

phytoplankton growth in natural waters 

(Maloney and others, 1972; Green and others, 

1975, 1976; Miller and others, 1976). The AGP 

determination used in this study is measured in a 

filtered water sample and, therefore, measures 

the potential for additional phytoplankton growth 

based on the nutrients that are biologically available. 

Figure 32 shows the mean annual concentrations of AGP, dissolved POrP, and N02 + 

N03-N from the upper to lower reaches of the 

study area. The AGP and nutrient concentrations 

were less than 10 and 0.4 mg/L, respectively, 

upstream of Atlanta. AGP decreased from about 

25 mg/L at Franklin to about 1 mg/L at the West 

Point dam pool. Dissolved P04-P decreased from 

0.1 mg/L at Franklin to less than 0.01 mg/L at the 

West Point dam pool, and dissolved N02 + N03-N 

decreased from 0.6 mg/L at Franklin to about 0.1 

mg/L at the dam pool. 
90,000 0.9 w 

X 

1- <( 

a: 

1-

80,000 0.8 z 

(/) 

:::» 

...J 

a: Q.. 

w w !::: 70,000 0.7 1- ...J D:a: ::::i 1-w ...J .. -~-

~ z_ 

/\ ...J 

a: 60,000 0.6 ca: EXPLANATION / \ Zw w X Total phytoplankton <(a.. Q.. / \, (/)(/) 

(/) • Dissolved orthophosphate as phosphorus J{ \ :::»::!: ...J a:<( uf 50,000 • Dissolved nitrite plus nitrate as nitrogen I 0.5 Oa: 

u :I:(!) Q.._ 

~ I (/)...J 

I 0:::! 

z if::!: ~40,000 I 0.4 z 

I (J)-

~ <( ' 

z z 

I ww 5 I 1-(!) 

~30,000 <(0 

·---· 0.3 &:I= 1-

>- _... (/)-

:I: _... ... oz Q.. ~ .. :I:(J) 

~20,000 I &<( I :I: 1- I 1- 0 a: 1- 0 

c 10,000 0.1 w 

> ...J 

0 

(/) 

(/) 

0 X )( 0 c 

400 380 360 340 320 300 280 260 240 220 200 

RIVER MILE 

FIGURE 31.-Mean annual concentration of total phytoplankton, dissolved orthophosphate, and nitrite plus nitrate by river mile. 

RELATION OF ALGAL GROWTH POTENTIAL TO 

NUTRIENTS IN WEST POINT LAKE 

Several regression equations were developed 

and used to evaluate the relation of dissolved concentrations of NH4-N, N02-N, N03-N, PO..-P, and 

SiOz (silica) to AGP in the West Point Lake. The 

equation (Cherry and others, 1978) determined 

from the regression of available data is: 

AGP (mg/L) = 211 (P04 -P, mg/L) 

+ 13.4 (N03 -N, mg/L) - 0.8. 

The multiple correlation coefficient and standard 

error of estimate are 0.96 and 3. 7 mg/L. Concentrations of dissolved P04 -P were more 

significantly related to AGP than corresponding 

concentrations of dissolved N03-N. 

39 

RELATION OF PHYTOPLANKTON GROWTH TO ALGAL 

GROWTH POTENTIAL IN WEST POINT LAKE 

Plots relating AGP and phytoplankton concentration to river mile downstream of Franklin at 

various temperatures are shown in figures 33 and 

34. A linear relation between miles downstream 

from Franklin and AG P and phytoplankton concentrations occurred during all sampling periods 

when AGP was greater than about 0.5 mg/L. 

Where AGP was less than about 0.5 mg/L, a decrease in the phytoplankton concentration occurred downstream. Therefore the availability of 

nutrients, as indicated by the AGP, appears to be 

limiting phytoplankton growth in the 

downstream reaches of the West Point Lake. 

The relationship between the rate of change of 

AGP with river mile from 10° to 30°C is defined by 

the following equation: 
where 

At -(0.0673T - 0.625), 

At= rate of change of AGP per river mile 

in milligrams per liter per river 

mile, and 

T =average water temperature, in degrees Celsius. 

Similarly, for phytoplankton the rate of change 

is defined by the following equation: 

where 

Pt = 0.0084T- 0.066, 

P t = rate of change of phytoplankton concentration per river mile, in (loge) 

cells per milliliter per river mile, 

and 

T =average water temperature, in degrees Celsius. 

Therefore, knowing the AGP at Franklin and 

the water temperature of the lake, the AGP and 

phytoplankton concentration can be estimated at 

downstream sites in the lake using the following 

equations: 

where 

Ca,. = AGP in milligrams per liter at river 

mile R, downstream from Franklin, 

At= rate of change of AGP, in milligrams 

per liter per river mile, 

where 

R =river mile downstream from 

Franklin, and 

Cai = AGP, in milligrams per liter at 

Franklin; 

CJJ,. =phytoplankton concentration in (loge) 

cells per milliliter at river mile R, 

downstream from Franklin, 

1.2 (I)Z 

w- I- ' 

EXPLANATION 

x---x~ )( 

<Cz J:w a..C!> (/)0 

oa:: _r 

<( 

i=a: Zw WI- I-- O..J 

a.. a: J:w I-C.. 

~(/) 

0~ a:<( 

(!)0: (!) _J- <(..J 

(!):::! 

..J~ 

<Cz 

z-

<( 

w 

~ 

20 

15 

10 

5 

0 

X Algal growth potential 

• Dissolved orthophosphate as phosphorus 

A. Dissolved nitrite plus 

nitrate as nitrogen 

RM River mile 

.... co~ Q) Ill~ =a: "C::::- ~a: 

E~ jg~ .......... 

~ ...... o...: > a.a: oci Uo ~E~ ZM '¢ M "0 co . (li""C~ 

Q>1i]M 

.::..=:-

co ..J 

~ ,ea: 

c..,.. 

com 

~g M 

1.0 ::t:!::: 

a..z 

0(1) J:<( 

1-w 

a: I0.8 O<Ca:: 

oa::w 

wt:t: >z...J 

..J(/)a:: 

O:::>w 

0.6 (/)..Jc.. 

~0..(1) 

Ow~ 

u..!:::<( 

Oa:a:: 

(/)t:S2 

0.4 zZ...J 

oo:::! 

i=Z~ <(<( 

a:(/) 

I-::> 

za: 

~0 ZJ: 

oa.. u(/) 0 ZJ: <(0.. 

UJ(/) c~ ~~ c~ 2<( Q)~ 

.... a; "E~ _Ea:: :::0: ~a: .Ea: ::len .::tt.co coo ~~ ~ ...... lllN C-.:t .......... ~~ co . C!)ci .... co co.- .... U') 0 . u..oo :.C(O U..('t) CON ..OM N ~N N ..JN ..0 ...... <(N 

FIGURE 32.-Mean annual concentration of AGP, dissolved orthophosphate, and nitrite plus nitrate by river mile. 

40 
P 1 = rate of increase of phytoplankton concentrations, in (loge) cells per milliliter per river mile, 

R =river mile downstream from 

Franklin, and 

c}Ji = phytoplankton concentration in (loge) 

cells per milliliter at Franklin. 

AGP at Franklin (Ca;) can be estimated from the 

relationship between AGP and nutrient concentrations at the Whitesburg station (following 

equation), because AGP at Whitesburg and 

Franklin is about the same (fig. 35). The Chattahoochee River at the Whitesburg Station is free 

flowing, which allows for development of nutrient 

concentration and flow relationships as shown in 

figure 36. The relationship between AGP and nutrient concentrations at the Whitesburg station 

was determined (Stamer and others, 1978) from a 

50 I I l 

A1 =-0.309 NOV. 16, 1975 

(cells/ml)/RM 16.8" c 

25 Ia: ... w - • - -

1- I ::i 0 I -- a: 50 w I I T a.. 

en ~ A1 =-0.231 DEC. 16, 1975 

~ 25 I- 13.1° c - <{ 

a: 

(.!) 1--- r- _a I 

::i 0 

:::! 

~ 50 

z A1 =-0.669 FEB. 24, 1976 

..1 25 14.JO c 

<{ 

~ 

z 

w 0 

1-

0 50 

a.. I I 

A1 =-0.327 

:I: MAR. 22, 1976 

1- 25 14.1° c ~ f-- - 0 ... a: 

(.!) 0 I • I - ...J 

<{ 50 

(.!) I I I ...J A1 =-0.692 APR. 17, 1976 <{ 20.go c 

25 f- -

L. 

I • - I • 00 10 20 30 35 

multiple linear regression analysis (correlation 

coefficient is 0.97) and is defined by: 

Cau· = 8.10 + 137.5 (POrP) + 4.61 (N03-N), 

where 

Ca 1c = AGP in milligrams per liter, at 

Whitesburg, 

PO.rP =dissolved orthophosphate (as phosphorus) concentration, in milligrams per liter, at Whitesburg, and 

N03-N =nitrate (as nitrogen) concentration, in 

milligrams per liter, at Whitesburg. 

PRESENT AND FUTURE EFFECTS OF POINT AND 

NONPOINT DISCHARGES 

ON ALGAL GROWTH IN WEST POINT LAKE 

The effects of PO.rP and N03-N concentrations, 

as measured by AGP, from point and nonpoint 

A1 =-0.409 MAY 19, 1976 

21.0" c 

0 10 20 30 35 

DISTANCE DOWNSTREAM FROM FRANKLIN STATION, IN RIVER MILES 

FIGURE 33.-0bserved AGP by river mile downstream from Franklin station. 

41 
discharges on phytoplankton concentrations in 

West Point Lake were estimated for lake water 

temperatures of 30°C for the following conditions: 

1. Average daily point-source POrP and N03-N 

loads, average daily nonpoint-source POrP 

and N03-N loads, and July mean monthly 

flow (3,490 ft 3/s) at Whitesburg. 

2. Average daily point-source PO.rP load based 

on phosphorus concentration of 1.0 mg/L and 

N03-N load, average daily nonpoint PO.rP 

and N03-N loads, and July mean monthly 

flow at Whitesburg. 

3. Observed June 1977 point-source P04-P and 

NOa-N loads, observed June 1977 nonpointsource P04-P and N03-N loads, and observed 

June 1977 flow (1,990 ft3/s) at Whitesburg, 

and, 

4. Average daily point-source load based on 

phosphorus concentration of 1.0 mg/L, ob15 I I I 

NOV. 16, 1975 P1=0.025 

16.8" c {cells/ml)/RM 10 1-- -

• 

a: • l I I w 5 • 

1-

:J 15 I J I :J 

..J DEC. 16, 1975 P,=0.063 

~ 10 13.1° c ~ - a: - .... w - a.. - I I I 

en 5 ..J 

..J 15 w I I I 

u FEB. 24, 1976 P1=0.064 Q) 14.JO c 

(!) 10 1-- - 0 .... ..J 

z 5 I I I 

2 15 0 I I I 

1-

~ MAR. 22, 1976 P1=0.075 

z 14.1° c 

~ 10 1- - ..J ... a.. 

0 5- 1 I • I • !> 

:I: 15 

a.. 

APR. 17, 1976 P1=0.123 

20.9° c 

10 

10 20 30 35 

served June 1977 point-source N03-N load, 

observed June 1977 nonpoint-source P04-P 

and N03-N loads, and observed June 1977 

flow at Whitesburg. 

A summary of the conditions and effects is 

shown in table 16. P04-P and N03-N concentrations at Whitesburg for condition 1 were determined from the concentration-flow relationships in figure 36. P04-P and N03-N concentrations at Whitesburg for conditions 2, 3, and 4 

were determined by converting the PO-t-P and 

N03-N loads at Whitesburg to concentrations 

based on the flow at Whitesburg. These analyses 

assumed that 50 percent of the phosphorus concentration in point discharges for conditions 2 and 

4 is dissolved P04-P and that the point-source 

NH4-H and N02-N concentrations are as NOa-N. 

The data indicate that with present (1978) 

P04-P and N03-N loads from point and nonpoint 

I I I 

P1=0.015 

1-- ~-

~ • MAY 19, 1976 

I I 21.0° C I 

• 

JULY 2, 1976 

26.6° c 

• 

• 

AUG. 10, 1976 

28.3° c 

• 

AUG. 24, 1976 

29.0° c 

P1=0.164 

• 

SEPT. 10, 1976 

25.6° c 

0 10 20 30 35 

DISTANCE DOWNSTREAM FROM FRANKLIN STATION, IN RIVER MILES 

FIGURE 34.-0bserved phytoplankton concentrations by river mile downstream from Franklin station. 

42 
50 I I I 

z 

::::; 

~ • 

z 40 • <(a: 

a:w 

L.Lt- :;::::; ' ~a: 

J-W 30 - za.. 

wen • ..... ~ I 2<C a: :I:(!) 20 f- • - t--

~::J oa:~ •• (.!)~ 

...J 10 f- - <( 

(.!) 

...J <( 

0 I 

0 10 20 30 40 50 

ALGAL GROWTH POTENTIAL (WHITESBURG), 

IN MILLIGRAMS PER LITER 

FIGURE 35.-Algal growth potential at Franklin versus algal 

growth potential at Whitesburg. 

sources and mean monthly July flows (3,490 ft 3/s) 

at Whitesburg the maximum phytoplankton concentration would be 2.6 x 105 cells/mL 19 river 

miles downstream from Franklin (RM 216) in 

West Point Lake. Phytoplankton concentrations 

could reach 3.6x 106 cells/mL at the dam pool with 

present point and nonpoint loads during an extended low-flow period such as the flow (1,990 

ft3

/s) observed at Whitesburg in June 1977. At the 

same Whitesburg flow, the maximum phytoplankton concentration in the lake would be 

1.2 x 105 cells/mL 15 river miles downstream from 

Franklin (RM 220. 71) with a concentration of 1.0 

mg/L of phosphorus in point discharges. 

Point-source discharges are estimated to increase from about 180 ft3

/s in 1976 to about 370 

ft 3/s in the Atlanta-to-Whitesburg reach by the 

year 2000. The future effects of PO-!-P and NOa-N 

concentrations, as measured by AGP, from point 

and nonpoint discharges on phytoplankton concentrations in West Point Lake were estimated 

for lake water temperatures of 30°C for the following conditions: 

1. Average daily point-source POrP and N03 -N 

loads with present levels of wastewater 

treatment, present average daily nonpointsource POrP and N03 -N loads and July 

mean monthly flow (3,490 ft3/s) at Whitesburg, 

43 

2. 

3. 

4. 

5. 

Average daily point-source POrP load based 

on a phosphorus concentration of 1.0 mg/L 

and NO:l-N load, present nonpoint-source 

POrP and NOa-N loads, and July mean 

monthly flows at Whitesburg, 

Average daily point-source PO-t-P load based 

on phosphorus concentration of 1.0 mg/L and 

NO:l-N load, nonpoint-source POrP and 

NO:l-N loads based on an increase of 100 percent urbanization in the Atlanta-toWhitesburg reach, and July mean monthly 

flows at Whitesburg, 

Average daily point-source PO-t-P and NO:l-N 

loads with present levels of wastewater 

treatment, present average daily nonpointsource PO-t-P and NO:l-N loads, and observed 

June 1977 flows (1,990 ft3/s) at Whitesburg, 

and 

Average daily point-source PO-t-P load based 

on phosphorus concentration of 1.0 mg/L and 

NOa-N load, present average daily 

nonpoint-source PO-!-P and NO:l-N loads, 

and observed June 1977 flows at Whitesburg. 

The data in table 16 show that with present 

wastewater treatment levels in the year 2000 

with flows at Whitesburg of 1,990 ft:l/s and 3,490 

ft3/s, the maximum phytoplankton concentrations 

in West Point Lake will be 3.6 million cells/mL at 

the dam pool and 2.4 million cells/mL about 2 

river miles upstream of the dam pool. Pointsource discharges containing 1.0 mg/L phosphorus and flows of 1,990 ft3

/s and 3,490 ft3/s at 

the Whitesburg station would result in the 

maximum phytoplankton concentrations of 6.3 x 

105 cells/mL at about the Abbottsford station and 

1.1 x 105 cells/mL at about the LaGrange station. 

The analysis of the present and future effects of 

point and nonpoint discharges on phytoplankton 

concentrations in West Point Lake at 30°C indicates that phytoplankton concentrations are dependent mostly on point discharges of phosphorus. Phytoplankton concentrations at 30°C 

could exceed 3 x 106 cells/mL during extended low 

flow (about 2,500 ft 3

/s at Whitesburg) with present average daily point-source POrP loads. In the 

year 2000, phytoplankton concentrations, at 

30°C, could reach 2 x 106 cells/mL with July 

mean monthly flows (3,490 ft3/s at Whitesburg) 

and with future daily point-source P04-P and 

N03 -N loads. 
1.0 

u) 

=> 

a: 

0 

::I: 

ll.. 

en 0 

0 0 ::I: a: a..w 

en!:: <(...J 

wa:: 1-w 0.1 

<(a.. 

:::cen 

ll..:;E 0 en<C Oa:: 

::I:(!) a.._ 

Q...J 

:::c::::! CD ~:E 

0~ 

c 

w 

> ...J 

0 

en 

en 

c 

0.01 L_ __ ___j_ __ L___j___j___j___l__Ll......L ___ __L_ _ __L____,s--_L_L__L_.J_J._ . ....J 

z' 

w 

1.0~--~--~~~~~~~---~--.-.--.-..-r~l 

(!)a: 

Ow 

a: I- I-- :z...J 

en a: <(~ 

wen 

~:E a::<C 

I- a: -(!) 

Z::J 

c::::! 

~:E 

...Jz 0-

en 

en 

c 

0 

10,000 100,000 

DISCHARGE, IN CUBIC FEET PER SECOND 

FIGURE 36.-Relationship of dissolved orthophosphate and dissolved nitrate concentrations to water discharge in the Chattahoochee River near Whitesburg. 

SUMMARY 

During the period April1975 to June 1978, the 

U.S. Geological Survey conducted a river-quality 

assessment of the Upper Chattahoochee River 

Basin to Georgia. Five objectives of the study 

were to: 

1. Evaluate the impact of heat loads from thermoelectric plants on stream temperature 

through the development of flow and temperature models. 

2. Assess the amounts of sediment transport and 

deposition. 

3. Assess the magnitudes and nature of point and 

nonpoint discharges to selected reaches of 

44 

the river and their effect on the DO regime 

of the river. 

4. Evaluate the economic considerations of maintaining desired minimum concentrations of 

DO in the Atlanta-to-Franklin reach of the 

river. 

5. Use microbiological determinations to develop 

quantitative methods to ·estimate algae concentrations in West Point Lake. 

Significant results of the study are: 

1. The combined thermal effects of flow regulation and powerplant effluents resulted in 

mean daily river temperatures downstream of the powerplants about equal to or 
TABLE 16.-Summary of present ( 1978) and future (year 2000) effects of point and non point phosphorus and nitrogen discharges on phytoplankton concentrations in West Point Lake 

[Concentrations are in milligrams per liter except for phytoplankton, in cells per milliliter, and flow, in cubic feet per second] 

Condition Level of Flow wastewater 

treatment 

1 Present --------------------------------3,490 2 Modified present3 ----------------------3,490 

3 Observed June 19774 --------------------1,990 

4 Modified observed June 1977 ------------1,990 

1 Present --------------------------------3,490 2 Modified present ________________________ 3,490 

3 Modified present ------------------------3,490 

4 Present --------------------------------1,990 5 Modified present ________________________ 1,990 

'River mile downstream of Franklin where AGP is 0.5 mg!L. 2

Phytoplankton concentration at river mile where AGP is 0.5 mg!L. 

Whitesburg 

Dissolved Dissolved orthophosphate nitrate as phosphorus nitrogen 

1976 

0.12 0.56 

.03 .56 

.34 1.0 

.06 1.0 

2000 

0.22 1.1 

.05 1.1 

.06 1.2 

.39 2.7 

.09 2.7 

West Point Lake 

Algal River mile' Phytoplankton2 

growth concentration potential 

27 19.06 260,000 

15 10.43 53,000 

.59 533.10 3,600,000 

21 14.75 120,000 

43 30.94 2,400,000 

20 14.39 110,000 

22 15.83 140,000 

74 6

3.10 3,600,000 

33 23.74 630,000 

3

Point P04 - P load based on 1.0 mg!L phosphorus concentration in discharge. •concentrations of nitrogen and phosphorus were not determined on filtered water samples. During low-flow conditions, dissolved and total values are nearly the same. "AGP at RM 33.10 is 13 mg!L. . "AGP at RM 33.10 is 28 mg!L. 

less than computed natural temperatures. 

An independent analysis of historical river 

and air temperature data provided the 

same basic conclusions. 

2. Except for periods of peak water-supply demand, simulated year 2000 river temperatures were little changed from observed, 

present-day (1978) temperatures. 

3. Average annual erosion yields ranged from 

about 900 to 6,000 tons per square mile per 

year. The greatest erosion yields occurred 

in those watersheds having large percentages of agricultural and transitional 

land uses. Erosion yields were lowest in 

urban watersheds. 

4. Timber harvesting increases annual sheet 

erosion by several orders of magnitude. 

5. Average yields of suspended sediment 

transported by streams ranged from 300 to 

800 tons per square mile per year. Yields of 

sediment were highest from urban watersheds and lowest from forested watersheds. 

A large part of the sediment discharged in 

urban streams was considered to be derived from channel erosion. 

6. Average annual unmeasured-sediment discharge ranged from about 6 to 30 percent of 

the total annual sediment discharge 

transported by streams. 

45 

7. Sixty percent or more of the annual load of 

phosphorus and trace metals was associated with suspended sediment. Suspended 

discharges of nitrogen and organic carbon 

ranged from about 10 to 70 percent of total, 

respectively. Yields of suspended nutrients 

and trace metals were highest from urban 

watersheds and lowest from forested areas. 

8. Average annual yields and daily concentrations for most constituents were largest 

in streams draining urban areas and 

smallest in streams draining forested and 

residential areas. 

9. On an average annual basis and during storm 

periods, nonpoint-source loads for most 

constituents were larger than point-source 

loads. 

10. Average annual point-source discharges accounted for about 50 percent of the dissolved nitrogen, total nitrogen, and total 

phosphorus loads and about 70 percent of 

the dissolved phosphorus loads at a station 

about 40 river miles downstream from Atlanta. 

11. Low DO concentrations in the river 

downstream from Atlanta occur during 

periods of warm weather when peak hydroelectric power is not generated at the 

upstream Buford Dam. 
12. Average daily concentrations of DO of less 

than 5.0 mg/L in the river, about 20 river 

miles downstream from Atlanta, occurred 

about 27 percent of the days from May 15, 

1977, to November 15, 1977. Minimum 

daily concentrations of DO of about 3 mg/L 

occurred during this period. 

13. During a low-flow period, five municipal 

point sources contributed 63 percent of the 

BODu, 97 percent of the ammonium as nitrogen, 78 percent of the total nitrogen, and 

90 percent of the total phosphorus loads at 

Franklin. Average daily concentrations of 

13 mg/L of BODu and 1.8 mg/L of ammonium as nitrogen were observed in the 

river about 2 river miles downstream from 

the R. M. Clayton and Cobb Chattahoochee 

wastewater treatment facilities. Oxidation 

of the high concentration of BODu and ammonium as nitrogen caused DO concentrations to decrease from about 8.0 mg/L at 

RM 299 to about 4.5 mg/L at RM 271. Nirogenous oxygen demands (k 3 = 0.19 to the 

base 10) accounted for about 52 percent of 

the decrease in DO concentrations in the 

upper reach of the river (RM 303 to RM 

271) and about 42 percent in the lower 

reach (RM 271 to RM 235). Carbonaceous 

oxygen demands were exerted at a k 1 equal 

to 0.07 to the base 10 at 20° Celsius. 

14. During a critical low-flow period, a 

streamflow at Atlanta of about 1,800 ft3/s 

(cubic feet per second) and point-source 

flows of 185 ft3/s containing concentrations 

of 45 mg/L of BODu and 15 mg/L ammonium as nitrogen result in a computed 

DO concentration of 4. 7 mg/L downstream 

from Atlanta. With point-source concentrations of 45 mg/L ofBODu and 10 mg/L of 

ammonium as nitrogen, present pointsource flows, and a streamflow of about 

1,500 ft 3 /s at Atlanta, the computed 

minimum DO concentration is 5.0 mg/L. 

With 45 mg/L of BODu, 5 mg/L of ammonium as nitrogen, and a streamflow of 

about 900 ft3/s, the minimum DO concentration is 5.5 mg/L. 

15. During a critical low-flow period in the year 

2000, point-source flows of 373 ft3/s, and 

concentrations of 15 mg/L BODu and 5.0 

mg/L of ammonium as nitrogen, and a 

46 

streamflow of about 1,000 ft3/s, result in a 

minimum DO concentration of 5.0 mg/L. 

Point-source flows containing BODu and 

ammonium as nitrogen concentrations of 

45 and 5 mg/L, respectively, require a 

streamflow of about 1,800 ft3/s to meet the 

DO concentration standard (average daily 

DO concentrations of 5.0 mg/L and not less 

than 4.0 mg/L) by the State of Georgia. 

16. The average annual river temperature in 

1976 was 14.0°C just upstream of the 

Atkinson-McDonough thermoelectric powerplants and 16.0°C just downstream from 

the powerplants. The highest temperatures 

and the greatest differences in temperature 

occurred during the summer months when 

streamflow is generally the lowest. During 

the June 1977 low-flow period, the heat 

load from the two powerplants caused an 

increase in river temperature of about 7°C 

and a subsequent decrease in the DO concentrations of about 0.2 mg/L. 

17. Analysis of wastewater management alternatives based on economic efficiency indicated that low-flow augmentation can be 

substituted for nitrification of wastewater 

to maintain minimum DO concentratiqns 

of 3.0 mg/L downstream from Atlanta between the years 1977 and 2000. The savings in waste treatment cost will more than 

offset the benefits foregone by the loss of 

peak-generating capacity at Buford Dam. 

Maintenance of a minimum DO concentration of 5. 0 mg/L will require nitrification of 

wastewater after about 1990. 

18. The lower concentration of the nutrient dissolved orthosphosphate as phosphorus is 

presently limiting phytoplankton growth 

in West Point Lake when water temperatures are greater than about 26°C. Estimated phytoplankton concentrations for 

1977 could exceed 3 million cells/mL at 

30°C, in West Point Lake if the algal 

growth potential at Whitesburg (Franklin) 

is about 50 mg/L during extended low flow 

(1,990 ft 3/s at Whitesburg) in June 1977. In 

the year 2000, phytoplankton concentrations in West Point Lake are not likely 

to exceed 700,000 cells/mL during extended 

low-flow periods in the summer if pointsource concentrations of phosphorus are 

not greater than about 1 mg/L. 
SELECTED REFERENCES 

Alexander, M., 1965, Most probable number method for microbial population, in Black, M. C. A., and others, ed., 

Methods of soil analysis, Part 2: Madison, Wisconsin, 

American Society for Agronomy. 

Amein, M. M. and Fang, C. S., 1970, Implicit flood routing in 

natural channels: Journal of the Hydraulics Division, 

American Society of Civil Engineers, v. 96, no. HY 12. 

Cherry, R. N., Luim, B. W., Shoaf, W. T., Stamer, J. K., and 

Faye, R. E., 1978, The effects of nutrients in algal growth 

in West Point Lake, Georgia: U.S. Geological Survey 

Open-File Report 78-8-137. 

Curtis, E. J. C., Durrmit, K., and Harman. M. M. I., 1975, 

Nitrification: Water Resources Bulletin, v. 10, p. 555-564. 

Ehlke, T. A., 1978, The effect of nitrification on the oxygen 

balance of the Upper Chattahoochee River, Georgia: U.S. 

Geological Survey Water Resources Investigations 79--10, 

19 p. 

Environmental Protection Agency, 1976, Water Quality 

Criteria. 

Environmental Protection Division, July 17, 1974,,Statement 

at public meeting, Lake Sidney Lanier project: Georgia 

Department of Natural Resources, Atlanta, Georgia. 

Environmental Protection Division, June 28, 1977, Water-use 

classification (including trout stream designations) and 

water quality standards for the surface waters of the State 

of Georgia: Georgia Department of Natural Resources, Atlanta, Georgia, 22 p. 

Faye, R. E., Carey, W. P., Stamer, J. K., Kleckner, R. L., and 

Cherry, R. N., 1978, Erosion, sediment discharge, and 

channel morphology in the upper Chattahoochee River 

Basin, Georgia: U.S. Geological Survey Open-File Report 

78-576. 

Faye, R. E., Jobson, H. E., and Land, L. F., 1978, Impact of flow 

regulation and powerplant effluents on the flow and temperature regimes of the Chattahoochee River-Atlanta to 

Whitesburg, Georgia: U.S. Geological Survey Open-File 

Report 78-528. 

Giffels, Black, and Veatch, February 1977, Overview plan 

with environmental assessment. Comparative 

wastewater collection and treatment costs: Detroit Water 

and Sewage Department, Detroit, Michigan, v. 1, Interim 

Reports, (Revised), 118 p. 

Greene, J. C., Miller, W. E., Shiroyama, T., and Maloney, T. 

E., 1975, Utilization of algal assays to assess the effects of 

municipal, industrial, and agricultural wastewater effluents upon phytoplankton production in the Snake 

River system: Water, Air, and Soil Pollution, v. 4, p. 

415-434. 

Greene, J. C., Soltero, R. A., Miller, W. E., Gasperino, A. F., 

and Shiroyama, T., 1976, The relationship of laboratory 

algal assays to measurements of indigenous phytoplankton in Long Lake, Washington, in Middlebrooks, E. 

J., Falkenborg, D. H., and Maloney, T. E., eds., Biostimulation and nutrient assessment: Ann Arbor, Michigan, 

Ann Arbor Science, p. 93-126. 

Greeson, P. E., Ehlke, T. A., Irwin, G. A., Lium, B. W., and 

47 

Slack, K. V., 1977, Methods for collection and analysis of 

aquatic biological and microbiological samples: U.S. 

Geological Survey Techniques Water-Resources Investigations, book 5, chapter A4, 332 p. 

Hines, W. G., McKenzie, S. W., Rickert, D. A., and Rinella, F. 

A., 1978, Dissolved-oxygen regimen of the Willamette 

River, Oregon, under conditions of basinwide secondary 

treatment: U.S. Geological Survey Circular 715-I, 52 p. 

Lium, B. W., Stamer, J. K., Ehlke, T. A., Faye, R. E., and 

Cherry, R. N., 1978, Biological and microbiological Assessment of the Upper Chattahoochee River Basin, Georgia: U.S. Geological Survey Circular 796, 22 p. 

Maloney, T. E., Miller, W. E., and Shiroyama, T., 1972, Algal 

responses to nutrient addition in natural waters-!. Laboratory assays, in Likens, G. E., ed., Nutrients and 

eutrophication-The limiting-nutrient controversy [Proceedings of Symposia J: American Society of Limonology 

and Oceanography, Special Symposia, v. 1, p. 134-140. 

Matulewich, V. A., and Finstein, M. S., 1978, Distribution of 

autotrophic nitrifying bacteria in polluted river (the 

Passaic): Applied and Environmental Microbiology, v. 35. 

p.67-71. 

Metropolitan Atlanta Water Resources Study Group, 1976, 

Metropolitan area, Water Supply Review Supplement: Atlanta, Georgia. 

Metropolitan Atlanta Water Resources Study, March 1977, 

Third progress report from the Metropolitan Atlanta 

Water Resources Study Group: Atlanta, Georgia, 11 p. 

Miller, W. E., Greene, J. C., and Shiroyama, T., 1976, Application of algal assays to define the effects of wastewater 

effluents upon algal growth in multiple use river systems, 

in Middlebrooks, E. J., Falkenborg, D. H., and Maloney, 

T. Ed., eds., Biostimulation and nutrient assessment: Ann 

Arbor, Michigan, Ann Arbor Science, p. 77-92. 

Oswald, U. J., and Golueke, C. G., 1966, Eutrophication trends 

in the United States-a problem?: Journal of Water Pollution Control Federation, v. 38, no. 6, p. 964-975. 

Schefter, J. E., and Hirsch, R. M., 1979, An economic analysis 

of selected strategies for dissolved oxygen management: 

Chattahoochee River, Georgia: U.S. Geological Survey 

Open-File Report 79-412. 

Stamer, J. K., Cherry, R.N., Faye, R. E., and Kleckner, R. L., 

1979, Magnitudes, nature, and effects of point and nonpoint discharges in the Chattahoochee River Basin, Atlanta to West Point Dam, Georgia: U.S. Geological Survey 

Water-Supply Paper 2059, 65 p. 

Tuffey, T. S., Hunter, J. V., and Matulewich, V. A., 1974, 

Zones of nitrification: Water Resources Bulletin, v. 10, p. 

555-564. 

U.S. Army Corps of Engineers, 1975, West Point Lake, Alabama and Georgia: U.S. Army Corps of Engineers, 

Savannah, Georgia. 

Velz, C. J., 1970, Applied stream sanitation: New York, John 

Wiley and Sons, 619 p. 

Wischmeier, W. H., and Smith, D. D., 1965, Predicting 

rainfall-erosion losses from cropland east of the Rocky 

Mountains: U.S. Department of Agriculture Handbook 

282, 47 p. 


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