GEOLOGICAL SURVEY CIRCULAR 796 

Biological and Microbiological 

Assessment of the Upper 

Chattahoochee River Basin, Georgia 

Biological and Microbiological 

Assessment of the Upper 

ChaHahoochee River Basin, Georgia 

By Bruce W. Lium, John K. Stamer, 

Theodore A. Ehlke, Robert E. Faye, and 

Rodney N. Cherry 

GEOLOGICAL SURVEY CIRCULAR 796 

1979 
United States Department of the Interior 

CECIL D. ANDRUS, Secretary 

Geological Survey 

H. William Menard, Director 

Library of Congress Cataloging in Publication Data 

Biological and microbiological assessment of the upper Chattahoochee River basin, 

Georgia. 

(Geological SurveyCircular 796) 

Bibliography: p. 

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

watershed. 3. Chattahoochee River. I. Lium, Bruce W. II. Series: United States. 

Geological Survey Circular 796. 

QE75.C5 no. 796 [QH105.G4] 557.3'08s [553'.78] 78-27331 

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

1200 South Eads Street, Arlington, Va. 22202 
CONTENTS 

Page Page 

Abstract ----------------------------------- 1 Phytoplankton __ ___ _ _ _ _ _ _ _ _ __ __ _ _ __ __ _ _ _ _ __ _ 7 

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

Acknowledgments --------------------------- 3 Algal growth potential ---------------------- 7 

Description of basin ------------------------ 3 

Relation of algal growth potential to nt'-

trients in West Point Lake ------------ 8 

IIydrology ------------------------------ 3 

Land use ------------------------------- 3 

Relation of the phytoplankton growth to th~ 

Water use ----------------------------- 5 algal growth potential ---------------- 12 

Future effects of water use on riverflow _______ 6 ~itrification _____ -------------------- __ _____ 15 

~ature of the problem ---------------------- 6 Summary and conclusions -------------------- 21 

Methods of data collection ------------------- 6 Referenc·es cited ---------------------------- 21 

ILLUSTRATIONS 

Page 

FIGURE 1. Map showing study area and sampling stations in the Upper 

Chattahoochee River basin -------------------------------- 2 

2.-22. Graphs showing: 

2. Flow durations of the Chattahoochee River at the 

Atlanta gage before and after construction of 

Buford Darn ----------------------------------- 4 

3. Phytoplankton concentrations by river mile for August 

1976 ------------------------------------------ 8 

4. Average diatom concentrations by month in Lake Sidney Lanier and West Point Lake -------------- 9 

5. Average green algae concentrations by month in Lake 

Sidney Lanier and West Point Lake ------------- 9 

6. Average blue-green algae concentrations by month in 

Lake Sidney Lanier and West Point Lake ------ 10 

7. Mean annual concentrations of total phytoplankton, 

dissolved orthophosphate, and nitrite plus nitrate 

by river mile ---------------------------------- 10 

8. Mean annual concentrations of algal growth potential, 

dissolved orthophosphate, and dissolved nitrite plus 

nitrate by river mile --------------------------- 11 

9. Comparison of calculated and observed algal growth 

potential -------------------------------------- 12 

10. Relation of phytoplankton concentrations to water temperature at sites in West Point Lake ------------ 13 

11. Plots of observed algal growth potential by river mile 

downstream from Franklin station -------------- 13 

12. Plots of observed phytoplankton concentrations by 

river mile downstream from Franklin station ____ 14 

13. Relationship of temperature to the rate of change of 

algal growth potential per river mile ------------ 14 

14. Relationship of temperature to the rate of change of 

phytoplankton concentration per river mile ------ 15 

15. Comparison of calculated and observed algal growth 

potential for each sampling period -------------- 16 

16. Comparison of calculated and observed phytoplankton 

concentrations for each sampling period --------- 17 

iii 
Page 

FIGURES 17.-22. Graphs showing-Continued 

TABLE 1. 

2. 

3. 

4. 

5. 

17. Estimated maximum phytoplankton concentrations at 

sites in West Point Lake at various temperatures 17 

18. Comparison of computed and observed dissolved-oxygen 

concentrations in the Atlanta to Franklin reach during low flow period, June 1-2, 1977 -------------- 18 

19. Comparison of decreases in dissolved oxygen resulting 

from nitrification to total decrease in dissolved 

oxygen in the Atlanta to Franklin reach during low 

flow period, June 1-2, 1977 ---------------------- 19 

20. Nitrosomonas population in Chattahoochee River water 

and benthic sediment during June 1-2, 1977 ____ 19 

21. Nitrobacter population in Chattahoochee River water 

and benthic sediment during June 1-2, 1977 ------ 20 

22. Mean concentrations of ammonium, nitrite, and nitrate 

in the Chattahoochee River during June 1-2, 1977 20 

TABLES 

Page 

Land use in the upper Chattahoochee River basin ---------------- 3 

Estimated average water use and generating capacity for electricgenerating facilities in the upper Chattahoochee River basin __ 5 

Estimated water-supply withdrawals in the upper Chattahoochee 

River basin for the years 1976 and 2000 --------------------- 5 

Estimated wastewater discharges to the Chattahoochee River and 

tributaries for the years 1976 and 2000 ---------------------- 5 

Water temperature, algal growth potential, and concentrations of 

nutrients and phytoplankton in West Point Lake ----------- 12 

CONVERSION FACTORS 

For use of those readers who may prefer to use metric units rather than English units, the conversion factors 

for the terms used in this report are listed below: 

English 

ft (foot) 

ft3/s (cubic foot per second) 

in. (inch) 

mi (mile) 

mi2 (square mile) 

Multiply by 

3.048x1o-l 

2.832X10- 2 

2.540 

2.540x1o-l 

1.609 

2.590 

iv 

Metric 

m (meter) 

m3/s (cubic meter per second) 

em (centimeter) 

mm (millimeter) 

km (kilometer) 

km2 (square kilometer) 
Biological and Microbiological Assessment of 

the Upper Chattahoochee River Basin, Georgia 

By Bruce W. Lium, John K. Stamer, Theodore A. Ehlke, Robert E. Faye, and Rodney N. Cherry 

ABSTRACT 

Biological and mic·robiological studies were conducted 

by the U.S. Geological Survey as a part of the Intensive River-Quality Assessment studies of the upper 

Chattahoochee River basin. Phytoplankton concentrations in cells per milliliter (mL) were generally higher 

downstream from Atlanta than upstream. The highest 

concentrations, mostly blue-green algae, occurred in 

West Point Lake with an average of 90,000 cells per 

milliliter (cells/mL) for the sampling period. The 

lowest concentrations occurred upstream of Lake Sidney Lanier (1,000 cells/mL). Dissolved orthophosphate 

and nitrite plus nitrate concentrations were highest in 

the river reaches and upper reaches of the two lakes 

and were lowest at the dam pools of both lakes. The 

high nitrite plus nitrate concentrations downstream 

from Atlanta were primarily a result of nitrification 

by N itrosomonas and N itrobacter bacteria. 

Algal growth potential was highest downstream from 

Atlanta (25 milligrams per liter (mg/L) at Whitesburg) and was the lowest in the headwaters and at the 

dam pools of Lake Sidney Lanier and West Point Lake. 

Analysis of data collected at sites in West Point Lake 

indicated that, from the upper to the lower reaches, 

algal growth potential decreased in response to increases 

in phytoplankton concentration. Algal growth potential 

and phytoplankton concentration changes were greater 

at higher temperatures than at lower ones. Little or 

no change occurred in the algal growth potential or 

in phytoplankton concentrations at temperatures lower 

than about 13°C. Phytoplankton concentrations appeared to be related to water temperature and location 

in the lake at sites where algal growth potential was 

greater than about 0.5 mg/L. Phytoplankton concentrations decreased downstream from .sites where algal 

growth potential was less than 0.5 mg/L. 

Concentrations of Nitrosomonas and Nitrobacter 

were higher in the river-bed sediment than in the water 

column on a number-per-milliliter and per-gram basis. 

The rate of nitrification in the Atlanta to Franklin 

reach of the river was comparatively low, that is, 0.02 

mg/L per hour. Nitrification was an important cause 

of dissolved-oxygen consumption in a 45-mi reach of 

the river downstream from the Atlanta wastewater 

treatment facilities. Dissolved-oxygen consumption as 

a result of nitrification may be greatest during low 

flow conditions when dilution of ammonium is least 

and time of travel is greatest. 

INTRODUCTION 

For more than 10 years, the Department of 

Interior, Advi1sory Committee on Water Data 

for Public Use has been concerned about water~ 

quality information needed for plannirg river 

basin development. Specifically, .the Committee 

has been concerned about the followirg: (1) 

Definition of existing water quality of the N a1 tion's rivers, (2) analysis of water~quality 

I 

trends, ( 3) desirability of advanced wastewater treatment on a national, State, or river 

I 

basin level, and ( 4) definition of the r~lationship of land use to water quality. 

In 1972, the Committee recommended that 

I the U.S. Geological Survey conduct nlultidisciplinary river-quality studies. The firrt study 

was conducted in the Willamette River basin, 

1 

Oregon, and began in January 1973. The objectives were to define the types and quantities of 

data required to assess river-quality problems 

and to develop methods for assessing t,_e planning alternatives in terms of potential impacts 

on river quality. 

The Chattahoochee River basin was selected 

as the study area for a second river-quality assessment. The river-quality as.sessment of the 

upper Chattahoochee River basin (fig. 1) up.. 

stream of the West Point Dam began April 1, 

1975. Its purpose is to provide meanill gful information to resource managers a.nd to suggest 

alternatives for basin development and for 

future uses of the Chattahoochee River, in 

which maintenance and improvement cf water 

quality are requisites. 

Obj ootives of the biological and microbiological study are the following : ( 1) to use biologi-
~ ~ 

35°.--------------.-------------------------------------.~------------------------· 

EXPLANATION 

RM River miles 

Basin boundary 

Sampllng stations 

~ ATLANTA- l Stody "" ) 

\J 

Base from U.S. Geological Survey 

quadrangle maps 1:24 000 

0 

I 

0 

PEACHTREE CREEK 

10 

I 

I 

10 

20 

I 

30 

I 

I 

20 

40 

I 

I 

50 KILOMETERS 

I 

30 MILES 

FIGURE 1.-Study area and sampling stations in the upper Chattahoochee River basin. 

2 
cal and microbiological data to aid in estimating 

water-quality conditions in selected river 

reaches and two lakes (West Point and Sidney 

Lanier), (2) to assess the potential for algal 

growth in both lakes and selected reaches of the 

river, and (3) to determine what factors affect 

biological and microbiological communities and 

populations. The scope of this report includes a 

discussion of hydrology, land use and water use, 

and general biological and microbiological conditions in the study area. 

Acknowledgments-We express our sincere 

appreciation for the interest shown by the Advisory Committee on Water Data for Public 

Use and the Advisory Committee's Working 

Group for River-Quality Assessments. 

DESCRIPTION OF BASIN 

The upper Chattahoochee River (fig. 1) rises 

on the southern slopes of the Blue Ridge Mountains in northeas.t 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 mi 2

• Land surface altitudes range 

frrom about 4,000 ft in the headwaters to about 

635 ft above West Point, Ga. 

Rainfall in the basin averages about 54 in. a 

year with higher rainfalls occurring in the upland areas and in the southernmost part of the 

basin. Annual air temperatures in the basin 

average about 16°C with the coldest temperatures occurring in the mountainous areas. 

HYDROLOGY 

The flow of the Chattahoochee River is dependent on rainfall and regulation by hydroelectric-generating facilities. The highest flows 

generally occur during the spring of the year, 

and the lowest, in late autumn. The average 

flow at Buford Dam, based on 35 years of 

record, is 2,168 ft3/s. At Atlanta, which is 

about midway in the study area, the average 

daily discharge based on 43 years of record, is 

2,603 ft3/s. A maximum discharge of 59,000 

ft3/s occurred at the Atlanta gage in 1946, and 

a minimum daily discharge of 296 ft 3 /s occurred in 1957. 

Flow in the reaches has been regulated for 

many years because of hydroelectric-generating facilities at Buford Dam and Morgan Falls. 

The most pronounced changes in regulated flow 

8 

have occurred subsequent to the construction 

of Buford Dam. Figure 2 shows the flow durations of the Chattahoochee River at ltlanta 

before and after regulation by Buford Dam. 

The frequency of both the higher and lower 

flows has decreased. 

In 1960, the city of Atlanta and the Georgia 

Power Co. modified the Morgan Falls Da.m and 

reservoir to provide· a minimum flow of 750 

ft 3 /s from Morgan Falls. In 1974, the Georgia 

Environmental Protection Division reccgnized 

the increasing demand for water supply ~.nd the 

need for high-quality water downstrean1 from 

Atlanta for waiter-quality maintenance r.nd required a minimum flow of 750 ft 3 js just upstream of Peachtree Creek. This requir<)ment, 

considering water-supply withdrawals, results 

in a minimum release from Morgan F:'.lls of 

approximately 1,100 ft3 js. 

LAND USE 

Land in the upper Chattahoochee River basin 

from its headwaters to the West Point Dam is 

predominantly forest (table 1). Upstrnam of 

Buford Dam, about 80 percent of the land is 

forested and 16 percent used for agriculture. 

Agricultural activities are concentrated in the 

stream valleys and on the lower slopes. Crops 

and pastures occupy a significant part of the 

agricultural land. Poultry operations, primarily 

broiler chicken production, are an econmnically 

dominant agricultural activity. GainesYille is 

the largest urban area in this part of the basin. 

TABLE 1.-Land use in the upper Chattahoochee River 

basin 

Land use (in square miles) 

Drain 

River Agricul- age Basin above: mile Urban ture Forest area 

Buford Dam ------ 248.32 36.8 164.6 838.6 1,040 

Atlanta ----------- 302.97 128.9 239.3 1,081.7 1,450 

Fairburn ---------- 281.88 371.5 310.2 1,378.2 2,060 

Whitesburg 259.85 395.6 372.2 1,662.1 2,430 West Point Dam -- 201.40 433.1 545.9 2,461.1 3,440 

In the river reach from Buford Dam to Atlanta, about 60 percent of the land is forested, 

22 percent is urbanized, and 18 percent is agricultural. About 40 percent of the agricultural 

land consists of cropland and pasture with corn 

and soybeans as the dominant crops. 

The basin from Atlanta to West Point Dam 

includes most of metropolitan Atlanta, the 

largest city in the basin. Land in the l tlanta 
0 

z 

0 

u 

w 

32,000 

28,000 

(/) 24,000 

0:: 

w 

D.. 

1-

w 

w 

u. 

u 

iii 20,000 ::> 

u 

~ 

~' 

0 

...J 

u. 

~ 16,000 

~ 

~ (/) 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\/_)929-1956 (Before dam construction) 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

1965-1976 (After dam construction) 

0 0.1 1 5 20 50 90 99 99.99 

PERCENTAGE OF TIME FLOW EQUALED OR EXCEEDED THE VALUE INDICATED 

FIGURE 2.-Flow durations of the Chattahoochee River at Atlanta gage before and after construction of Buford Dam. 

area is predominantly residential, but com- I ties include automobile assembling, food procesmercial and industrial activities are significant. I sing, and light manufacturing. Downstream 

Some of the more important industrial activi- from Atlanta, forest land is predominant. 

4 
Agricultural use of the land is about the same 

as in the Buford Dam-Atlanta. reach, and the 

types of agricultural operations are similar. 

WATER USE 

The waters of the upper Chattahooche River 

are utilized extensiv·ely for power generation, 

water supply, water-quality maintenance, and 

recreation. 

Six electric, power-generating facilities are 

located adjacent to the Chattahoochee River and 

have a combined generating capacity of about 

3.8 million kilowatts. Buford Dam and Morgan 

Falls Dam are peak-power, hydroelectric-generating facilities and plants. Atkinson, McDonough, Yates, and Wansley are fossil-fuel 

thermoelectric powerplants. Morgan Falls is a 

run ... of-the-river facility which utilizes hydropower-released waters from Buford Dam. The 

estimated average water use and generating capacity for the plants are shown in table 2. 

TABLE 2.-Estimated average water use and generating 

capacity for electric-generating facilities in the upper 

Chattahoochee River basin 

[Data provided by Georgia Power Co.] 

Hydroelectric facilities 

Average 

River 

mile N arne of facility 

Hydroelectric facilities 

348.32 Buford Dam ------------- 312.62 Morgan Falls Dam -------

Capacity 

(kilowatts) 

86,000 

16,800 

Thermoelectric facilities 

299.11 

259.70 

249.20 

Atkinson-McDonough -----

Yates Wansley -------------------- ________________ _ 

a One small unit online in 1976. 

730,000 

1,250,000 

1,760,000 

water 

use 

(ft3/s) 

2,200 

2,500 

909 

1,030 

n 73 

In 1976, water-supply withdrawals in the 

upper Chattahoochee River basin were about 

290 ft3 /s, of which about 276 ft3 /s. was withdrawn directly from the Chattahoochee River 

in the re31Ch from Buford Dam to Fairburn. 

Other water supplies were withdrawn from 

Lake Sidney Lanier and West Point Lake. Table 

3 lists the major water users in the basin and 

shows p~resent (1976) and estimated withdrawals for the year 2000. Large amounts. of 

wastewater are discharged to the Chattahoochee River, particula.rly in the Atlanta area 

(table 4). 

Several reaches of the river are used extensively for recreation. The mountainous headwater areas are popular for trout fishing, 

5 

TABLE 3.-Estimated water-supply withdrawals in the 

upper Chattahoochee River basin for the ye~-rs 1976 

and 2000 

[Data provided by Metropolitan Atlanta Water Resources Study 

G1·oup] 

WithdrawFls (ft3js) 

Facility River mile 1976 2000 

Hall County" -------------- Forsyth County a -----------

Gwinnett County a ----------

City of Buford a -----------

Gwinnett County ----------- DeKalb County ------------- Atlanta-Fulton County ------

Cobb County --------------- City of Atlanta ------------ City of LeGrange ----------

Total _- __ ------------

338.92 

325.44 

310.85 

300.62 

214.37 

"Withdrawals upstream of Buford Dam. 11 from plant records 

1 

12 

91 

39 

134 ~ 

11 

291 

9 

2 

68 

1 

12 

187 

243 

117 

110 

12 

761 

TABLE 4.-Estimated wastewater discharges to the 

Chattahoochee River a.nd tributaries for ti.e years 

1976 and 2000 

I Data obtained from Metropolitan Atlanta Water Resout·ces Study 

Group, 1976] 

Location 

Cainsville Linwood a ---------

Cainsville Flat Creek a ------

Buford ---------------------- .John Creek ----------------- Crooked Creek -------------- Big Creek ------------------ Cobb-Chattahoochee __ - ---- __ 

R. M. Clayton --------------- Hollywood ------------------- South Cobb ----------------- Utoy ----------------------- Sweetwater ----------------- Camp Creek ---------------- Regional Interceptor --------- Annewakee Creek -----------

Bear Creek ----------------- LaGrange Yellow Jacket ___ _ 

Total __ --- ____ ----- _--

11 Upstream of Buford Dam. 

River 

mile 

338.12 

329.30 

325.15 

317.37 

300.56 

300.24 

297.50 

294.28 

2!11.60 

288.58 

283.78 

2xt.46 

275.95 

214.12 

Discharges ( ft3 /s) 

1976 2000 

2.2 4.2 

5.6 9.3 

1.7 2.0 

2.9 4.8 

1.8 12 

4.1 17 

15 31 

118 161 

2.3 

13 48 

21 44 

2.6 

6.8 27 

42 

6.0 

7.7 

1.5 3.0 

196 422 

camping, and hunting. Lake Sidney Lr.nier, a 

popular water resort area, has numero~Js public aceess 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 N ation (Metropolitan Atlanta Water Resources 

Study Group, 1976). The reach from Buford 

Dam to Atlanta is periodically ·stockr·!} with 

game fish and provides recreation for fishermen, canoeists, and rafters. This reac1' is being considered for an urban national park. The 

reach between Morgan Falls Dam and Peachtree Creek is one of the most scenic on the river 

and is the site for an annual raft race that inv;olves thousands of participants. and onlookers. 

The shoals in the reach from Whitesburg to 

Franklin are popular for fishing and boating. 
West Point Lake, a U.S. Army Corps of Engineers impoundment created by the construction 

of West Point Dam in 197 4, is us.ed for fishing, 

boating, camping, and swimming. 

FUTURE EFFECTS OF WATER USE ON 

RIVERFLOW 

Future consideration for modifying the flow 

regime from Buford Dam to meet increasing 

demands for water supply include construction 

of a new regulation structure downstream 

from Buford Dam, modification of Morgan 

Falls Dam and reservoir, or changes in the 

hydropower releases from Buford Dam (Metropolitan Atlanta Water Resources Study, 1977). 

In the year 2000, during an extended drought 

period such as occurred in 1954-56, a minimum 

flow of 1,717 ft:1/s could be maintained from 

Buford Dam. Considering water-supply withdrawals, wastewater returns, and no streamflow accretions between Buford Dam and Atlanta, the estimated net flow at Atlanta in the 

year 2000 would be 1,310 ft:1ls. The flow would 

provide 560 ft 3

/ s for water supply downstream 

from the Atlanta gage and 750 ffl/s for waterquality maintenance. Average water-supply 

withdrawals in the reach from Buford Dam to 

Fairburn (RM 281.88) are estimated to be 

669 ft 3 Is (table 3) in the year 2000. During 

a drought period, net flow at Fairburn, assuming no accretion of tributary inflow and an 

average wastewater return of 350 ft3 Is, would 

be 1,398 ft 3

/ s or about the same that occurred 

during low flow periods in 1976. 

NATURE OF THE PROBLEM 

The problems as.sociated with water quality 

in the upper Chattahoochee River basin are 

generally related to urbanization. Urbanization 

has created large demands on the Chattahoochee River as the major water supply for Atlanta and as the major transporter of municipal wastes from Atlanta. In 1976, about 280 

ft3ls was withdrawn from the river upstream 

of Peachtree Creek (river-mile (RM) 300.54) 

for water-supply and about 180 fV Is of secondary treated wastewater was discharged into the 

river between Peachtree Creek and Fairburn 

(RM 281.88). In this reach two thermoelectric 

powerplants withdraw and subsequently discharge heated effluent directly into the river. 

The net effect of discharges from these power6 

plants and fr1om other point sources is to reduce the waste-assimilative capacity of the 

river. 

During periods of rainfall, combined sewer 

overflows and direct runoff from streets and 

parking lots can contribute large dissolved and 

suspended constituent loads to the river. During 

these periods, sediment loads carried by the 

Chattahoochee River and its tributaries can be 

high. During periods of low flow, low dissolved 

oxygen (DO) and high biochemical oxygen demand (BOD) concentrations and high fecal 

coliform bacteria counts occur in the river 

downstream from Atlanta. 

Several alternatives have been J: ~oposed to 

modify the flow regime of the river to meet 

the increasing water-supply demand. Regardless of which alternative is selected, streamflow downstream from Atlanta will not be 

greatly different from that at present, and 

wastewater discharges will increase. 

METHODS OF DATA COLLECTION 

Biological, microbiological, chernical, and 

physical data were collected from October 

1975 to September 1976 at strean1 and lake 

stations shown on figure 1. Monthly water 

samples were collected at each stat~ 0n for determination of algal growth potential (AGP), 

phytoplankton, dissolved nitrate as nitrogen 

(NO:~- N), and dissolved orthophosphate as 

phosphorus (P04- P) concentrations. Additional wat•er samples were collected for chemical and microbiological determinations during 

low and high streamflows. 

Water samples. for determination of AGP 

were filtered in the field in a pressure· vessel 

through a 0.22-micrometer Millipore1 filter at 

pressures of less than five pounds per square 

inch and then chilled to 4 oc. The· algal assay 

is a widely used procedure, but two basic 

methods of sample preparation exist. One 

method (Greene and others, 1975; Miller and 

others, 1975) autoclaves the sample before 

filtration, provides a total AGP. The total AGP 

is usually higher than the dis,solved AGP because autoclaving releases nutrients from the 

plankton. The other method, def'~ribed by 

Greeson and others (1977) measur~s the dissolved AGP and was used throughout the study. 

1 The use of the brand names in this report is for ident~fication 

purposes only and does not imply endorsement by the U.S. Geo- logical Survey. 
Unfiltered samples for phytoplankton determinations were preserved with a solution containing copper sulfate, formaldehyde, and a 

detergent. Water samples for nitrogen and 

phosphorus determinations were filtered in the 

fi·eld through a 0.45-micrometer Millipo,re filter. 

Nitrifying bacteria and related chemical constituents were measured during sustained low 

flow in the Chattahoochee River. The flow was 

maintained at 1,150 ft3/s for 3 days before Bampiing on June 1-2, 1977. Nitrifying bacteria 

were determined from water and riverbed 

samples collected at sites shown on figure 1. 

Water samples were collected in 1-L autoclaved 

bottles made of polypropylene using depth-integrat,ed techniques. Riverbed samples were 

collected using a USGS, BM 60 sampler. After 

retrieving the sample, the top 1 em of sediment was subsampled with a sterilized test tube 

and placed in a sterile Whirlpak1 plastic bag. 

Both water and sediment samples were placed 

in an ice chest while en route to the laboratory. 

In-stream. DO and te~mperature measurements 

were made using a DO meter (Yellow Springs 

model 57) .

1 Separate water samples were collected for laboratory determinations of BOD, 

NH4-N (ammonium as nitrogen), N02-N 

(nitrite as nitrogen) and NO~- N. The laboratory chemical methods used are described by 

Brown and others (1970) with the exception of 

BOD, which was determined by the method described by Hines and others (1977). 

Nitrifying bacteria in water column and 

riverbed sediments were determined by a modification of the three tube most probable number (MPN) procedure described by Greeson 

and others (1977). A 1-mL aliquot of culture 

material was tested for the presence or absence of nitrite at intervals of 30, 45, and 60 

days and the highest value (usually the last 

one) was recorded as the MPN estimate. 

PHYTOPLANKTON 

Concentrations of phytoplankton (diatoms, 

green algae, and blue-green algae) were generally higher downstr·eam from Atlanta than 

upstream. Concentrations of phytoplankton 

were higher in Lake Sidney Lanier (a bottomrelease dam) and West Point Lake than in the 

river and tributaries, with maximum concen- 1 The use of the brand names in this report is for ident~fieation 

PU~poses only and does not imply endorsement by the U.S. Geo- logical Survey. 

' trations occurring in W~est Point LakE. downstream from Franklin. 

7 

Figure 3 shows phytoplankton concentrations from the headwaters of the Chattahoochee 

River to the West Point Dam during August 

1976. The highest concentrations (mostly bluegreen algae) occurred in West Point Lake. The 

lowest concentration occurred at Norcross. 

Figures 4, 5, and 6 ~show the monthly variation 

in average concentrations of the variour phytoplankton genera in Lake Sidney Lanier and 

West Point Lake. Average concentrations. of 

blue-green and green algae were highest in 

West Point Lake. In the spring, montl'ly concentrations of diatoms (fig. 4) were highest 

in Lake Sidney Lanier. The spring diatom increag.e, as shown in figure 4, did not occur in 

West Point Lake. Blue-green algae were dominant in both lakes,, and concentratiors were 

highest during the summer months. Diatom 

c10nc,entrations generally exceeded the greenalgae concentrations. in both lakes. 

Figure 7 shows mean annual concentrations 

of total phytoplankton, dissolved P0-1- P, and 

N02 + N03- N from the upper reache·~:· of the 

Chattahoochee River to the West P10irt Dam. 

Phytoplankton concentrations upstream of 

Lak~e Sidney Lanier were les1s than 1,0( () cells/ 

mL, and in the lake they were about 10,000 

cells/mL. Concentrations downstrean1 from 

Lake Sidney Lanier to the upstream end of 

West Point Lake at Franklin were less than 

4,000 eells/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 lake:s, and lowest 

at the dam pools of both lakes. Tl' ~ high 

N02 + N03- N concentrations downstrer.m from 

Atlanta we·re primarily a result of nitrification 

of treated sewage effluent by the Nitrosomonas 

and Nit1·obacter bacteria (Ehlke, 1978). 

ALGAL GROWTH POTENTIAL 

Figure 8 shows the mean annual concentrations of AGP, dissolved P04- P and 

N02 +NO a-N from the upper to lower reaches 

of the study area. The AGP and nutrient concentrations were less than 10 and 0.4 rr<r/L respectively upstream of Atlanta. 

AGP decreased from about 25 rng/L at 

Franklin to about 1 mg/L at the Wert Point 

Lake dam pool. Dissolved P04- P d~reased 
a: 

w 

I-

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::::i 

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~ 

a: 

w 

0.. 

en 

....J 

....J 

w 

u 

~ 

z' 

0 

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100,000 

10,000 

1000 

EXPLANATION 

X Total count 

• Blue-green algae 

• Green algae 

• Diatoms 

RM River mile 

' I 

I 

I 

I 

I I 

I I 

I I 

/ / I 14 ,1 I I IX 

I ~ J.. ,i;'\ 

I ~ /~ /,l''v' / \ I " / I /"" ', I ~ "' I I \ 

I --~ ~ ,•......... // I : ~ JJr--1· -- ~ I , I I •i_: _________ "' / ''!Y'--- I / 

' \~\ / ~ ---;------ ,~~ )', //,/ ............ I ~\ / ~; """"" I I 

\/__ ._/ 100~---L------------~----~~-~~~~~~--~L---~L-----~--~~~~~~--~ 

co~ ::a: 

Q)M E.q 

o...: 

u~ 

.... 

Q) 

·c::::::-

~g~ 

> c.a:: 

"'C 

~E~ co . (j)"'C~ 

a>1QM 

~-co 

....J 

en~ co~ :go: -a: .... ,..... c,.... 

~0') ~" oci ~N ZM 0 M M 

c~ ~~ c~ Q)~ 

'-0:: _5o: ::0:: ~a: ::Jcn ~co ~0 

~'""": 0N C.q !'""": co . (!)'""": co.- '-LO 0 u..oo :E(O U..(Y) CON N ~N N ....JN 

FIGURE 3.-Phytoplankton concentrations by river mile for August 1976. 

"E~ 

.Eo: 

~[0 0 . .CM 

.c..-

<(N 

Q) 

~ - ~~g 

1: a: c. ·- o E ~"<:t.co 

-c;-c 

~N1ij 

~ -

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. 

Y = bo+ b1X1 + b2X2 + .................. bnXn (1) 

was used to determine the relation of various 

nutrients to AGP. The regression equation includes a dependent variable designr.ted as Y; 

several independent variables designated as 

RELATION OF ALGAL GROWTH POTENTIAL TO 

NUTRIENTS IN WEST POINT LAKE 

A multiple-variable regression equation of 

the general form 

8 

Xh X2 ................. Xn; and partial regres<;'ion coefficients designated as bo, b1, b2 .................. bn. The subscript n indicates the number of irdependent 

variables. 
a: 

w 

~ 

::::i 

::::i 

....J 

~ 

a: 

w 

0.. 

C/) 

....J 

....J 

w 

u 

~ 

25,000 

en 1o,ooo ~ 

~ <( 

6 

5000 

7000 

ffisooo 

~ 

::::i 

::::i 

....J 

~ 5000 

a: 

w 

0.. 

C/) 

....J 

u:l4000 

u 

~ 

w 

(3 3000 

....J 

<( 

z 

w 

~ 2000 

(.!) 

EXPLANATION 

---•--- Lake Sidney Lanier 

)( West Point Lake 

•••··•••••••••• No data 

• 1\ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

I \ I \ 

I \ I \ 

I \ 

I \ 

I \ 

I \ 

I \ 

.. \ ... .,..,. \ .. -···· 

NOV. 

(1975) 

JAN. FEB. 

.,..,. -·····'t' ;t' \ 

MAR. APR. MAY 

(1976) 

JUNE JULY AUG. 

FIGURE 4.-A verage diatom concentrations by month in Lake Sidney Lanier and West Point Lake. 

EXPLANATION 

--+ -- Lake Sidney Lanier 

)( West Point Lake 

·--·---·----····· No data 

.·~ .. ··· \ ..... \ ... ·· \ .. ··· \ ..... \ ..... \ 

.. /........ \ 

... · 

.•· ... · 

1000 ......................... ',,,··································· 

SEPT. 

0 >t----- ~~ ~···· ........... i .................... __ 

OCT. NOV. DEC. JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. 

(1975) I (1976) 

FIGURE 5.-Average green algae concentrations by month in Lake Sidney Lanier and West Point L6ke. 

9 
~250,000.-----~------~----~------~----~------~----~~----~------~----~----~ 

w 

~ 

:::::i 

::::i 

...J 

~ 200,000 

~ 

w 

a.. 

~ 150,000- ...J 

w 

(.) 

~ 

~' 100,000 

(.!) 

...J 

<( 

z 

w 

w 

a: 

(.!) 

w 

:::J 

...J 

cc 

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 6.-A verage blue-green algae concentrations by month in Lake Sidney Lanier and West Point Lake. 

80,000 

a: 

w 

1-70,000 

::::i 

::::i 

...J 

~ 

a: 60,000 

w 

a.. 

(/) 

...J 

u:l50,000 

(.) 

~ 

z' 

~40,000 

:::.:::: 

z 

<( 

...J 

g,3o,ooo 

~ :::c 

a.. 

~20,000 

1-

0 

I10,000 

0 

EXPLANATION 

)( Total phytoplankton 

-----•---- Dissolved orthophosphate as phosphorus 

__ ......_ __ Dissolved nitrite plus nitrate as nitrogen 

I 

I 

_,..----' 

r; ~., 

I 

I 

I 

I 

400 380 360 340 320 300 280 

RIVER MILE 

\ / \ 

// \ / \ 

f 

I 

I 

I 

I 

I 

260 240 

\ 

\ 

\ 

\ 

A 

\ 

w 

~ a: 1-

0.802 (/) 

:::J 

...J 

a.. 

w 0.70!::: 

~ffi 

z!::: ...J 

oc:r:: 0.60Z w <Ca.. 

(/)(/) 

:::J~ 

c:r::<( 

0.50 ~a: 

a..£2 

(/)...J 

0::::! 

5:~ 

0.40 (/) ~ 

<Cz 

ww 

~(.!) 

<(O 

0.30 5: ~ 

~z 

:CCI) 

0..<( 

0.20~ 1-

a: 

0 

0 

0.10~ ...J 

0 

(/) 

(/) 

0 

FIGURE 7.-Mean annual concentrations of total phytoplankton, dissolved orthophosphate, and nitrite plus 

nitrate by river mile. 

10 
25 

..1 

<( 

i=a: 

Zw 

WI- 1--

Q-l 20 C.. a: :::I:w 

t-0.. 

~(/) 

0~ 

a:<( 15 

(.90:: 

(.9 _J-

<(::j 

(,9-

-l~ 

<(z 10 

z-

<( 

w 

~ 

5 

EXPLANATION 

)( Algal growth potential 

_ _...._Dissolved orthophospate as phosphorus 

-·-·•·-·- Dissolved nitrite plus nitrate as nitrogen 

RM River mile 

/ ,/· 

..................... /. 

/. 

FIGURE 8.-Mean annual concentrations of algal growth potential, dissolved orthophosphate, and nitrite plus 

nitrate by river mile. 

Regression parameters used in this study include the multiple correlation coefficient and 

the standard error of estimate, which indicate, 

respectively, the degree of association between 

the dependent and independent variables and 

the predictive quality of the regression model. 

Significance tests used were the F-test and ttest. Values of F indicate the "worth" of the 

entire regression, and values of t are measure 

of the significance of the regression parameters. 

Several regression equations based on the 

general form described were developed and 

used to evaluate the relation of dissolved 

concentrations of NH4-N, N02-N, N03-N, 

P04-P, and SiOz (silica) to AGP. The best 

equation determined from the regression of 

available data (table 5) from West Point Lake 

is defined by equation 2, which shows that orthophosphate and nitrate are the principle nutrients aff·ecting AGP (Cherry and others, 

1978). 

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

+ 13.4 (N03- N, mg/L) -0.8 (2) 

The multiple correlation coefficients and 

standard error of estimate of equation 2 are 

0.96 and 3.7 mg/L. The computed F of the regression is 172.5, which is significant at 2 level 

of confidenc•e greater than 99 percent. The significance of orthophosphate and nitrate concentrations relative to APG is indicated l~y the 

results of the t-test as follows: 

11 

coefficient computed t 

Levels of significance oft 

b1 (P04-P) --------- 8.02 --------- 0.1 perCE'"lt 

b2 (N03-N) --------- 3.10 --------- 0.1 percent 

Thus, concentrations of dissolved orthophosphate are shown to be more significantly related to AG P than corresponding concentrations of dissolved nitrate. Statistically, both 

parameters are highly significant. 

A comparison of calculated (equation 2) and 

observed AGP, as presented in figure 9, shows 

that AGP in West Point Lake can be estimated 

when only concentrations of dissolved orthophosphate and nitrate are known. 
TiABLE 5.-Water temperature, algal growth potential, a-rUt concentrations of nutrients and phytoplankton in 

West Point Lake 

Location 

(river mile) 

Collection 

period 

Average lake 

temperature 

Nitrate 

NOa-N 

(mg/Q 

Orthophosphate Algal gr<?wtb Phytoplankton 

PO 1 - P potential ( cells/mU 

Franklin 

(0.0) 

LaGrange 

(14.2) 

Abbottsford 

(24.8) 

Dam pool 

(33.1) 

Nov. 15-18, 1975 --------- Dec. 16-17, 1975 ---------

Feb. 24, 1976 ------------

Mar. 22, 1976 ----------- Apr. 17, 1976 ------------ May 19-20, 1976 ---------

July 2, 1976 ------------

Aug. 10, 1976 ----------- Aug. 24, 1976 -----------

Sept. 10, 1976 -----------

Nov. 15-18, 1975 ---------

Dec. 16-17, 1975 -------- Feb. 24, 1976 ------------ Mar. 22, 1976 ----------- Apr. 17, 1976 ------------ May 19-20, 1976 --------- July 2, 1976 ------------ Aug. 10, 1976 ----------- Aug. 24, 1976 ----------- Sept. 10, 1976 -----------

Nov. 15-18, 1975 -------- Dec. 16-17, 1975 --------- Feb. 24, 1976 ----------- Mar. 22, 1976 ------------ Apr. 17, 1976 ----------- May 19-20, 1976 --------

July 2, 1976 ------------ Aug. 10, 1976 ----------- Aug. 24, 1976 ----------- Sept. 10, 1976 -----------

Nov. 15-18, 1975 -------- Dec. 16-17, 1975 ---------

Feb. 24, 1976 ------------ Mar. 22, 1976 ----------- Apr. 17, 1976 ----------- May 19-20, 1976 ---------

July 2, 1976 ------------ Aug. 10, 1976 ----------- Aug. 24, 1976 ----------- Sept. 10, 1976 -----------

(OC) 

16.8 

13.1 

14.2 

14.1 

20.9 

21.0 

26.6 

28.2 

29.0 

25.8 

16.8 

13.1 

14.2 

14.1 

20.9 

21.0 

26.6 

28.2 

29.0 

25.S 

16.8 

13.1 

14.2 

14.1 

20.9 

21.0 

26.6 

28.2 

2'9.0 

25.8 

16.8 

13.1 

14.2 

14.1 

20.9 

21.0 

26.6 

28.2 

29.0 

25.8 

0 10 20 30 40 50 

OBSERVED ALGAL GROWTH POTENTIAL, 

IN MILLIGRAMS PER LITER 

FIGURE 9.-Comparison of calculated and observed 

algal growth potential in the West Point Lake from 

Franklin to West Point Dam. 

0.76 

0.55 

0.43 

0.58 

0.71 

0.84 

0.84 

0.96 

0.43 

0.52 

0.32 

0.24 

0.41 

0.56 

0.70 

0.50 

0.73 

0.54 

0.51 

0.24 

0.13 

0.40 

0.0 

0.25 

0.26 

0.25 

0.46 

0.40 

0.35 

0.22 

0.10 

0.00 

0.01 

0.06 

0.09 

(mg/Q (mg;L) 

0.10 

0.10 

0.02 

0.06 

0.12 

0.13 

0.10 

0.14 

0.02 

0.05 

0.01 

0.0~ 

0.03 

0.04 

0.05 

0.03 

0.02 

0.01 

0.03 

0.01 

0.00 

0.01 

0.0 

0.00 

0.00 

0.00 

0.00 

0.01 

0.00 

0.00 

0.00 

0.00 

0.01 

0.00 

0.00 

13.0 

33.0 

25.0 

12.0 

24.0 

13.0 

28.0 

36.0 

30.0 

43.0 

14.0 

5.7 

16.1 

5.8 

5.0 

13.0 

20.0 

22.0 

19.0 

18.0 

13.1 

2.4 

8.9 

3.6 

2.1 

3.8 

1.5 

0.3 

0.6 

o.a 

0.7 

1.4 

2.8 

0.9 

0.9 

0.5 

0.7 

0.4 

0.5 

0.4 

2,400 

1,000 

1,100 

410 

500 

3,600 

6,300 

19,000 

3,800 

1,200 

310 

2,100 

1,900 

250 

4,100 

3,200 

94,000 

240,000 

120,000 

23,000 

930 

5,000 

3,700 

670 27,000 

14,000 

140,000 

130,000 

560,000 

66,000 

6,100 

7,500 

10,000 

6,200 

21,000 

40,000 

30,000 

27,000 

62,000 

43,000 

RELATION OF PHYTOPLANKTON GF 0WTH TO 

THE ALGAL GROWTH POTEN~IAL 

Plots relating phytoplankton con~entrations 

to water temperature at sites in West Point 

Lake are shown in figure 10 (Cherry and 

others, 1978). Phytoplankton COJ]centrations 

increa-se with increasing temperature at all 

sites. The concentrations are generally higher 

at downstream sites than at ups~ream ones 

at the s·ame temperature, except at the dam 

pool, where the concentrations are l'lwer at the 

higher temperatures than at the Abbottsford 

site. 

The observed AG P and phytoplankton concentrations. are plotted against river miles 

downstream from the Franklin station in Figures 11 and 12. A linear relation between miles 

downstream of Franklin and AG P and phytoplankton concentrations occurred during all 

sampling periods when AGP was greater than 

about 0.5 mg/L. 

Figures 11 and 12 and data in table 5 (JulySeptember 1976) indicate that, ,.vhere algal 

12 
15 I I I I I I I I I I I I 

Q; • (.!) 

oa: 

-.JW 

-~ 

~~10- • - - ~_J 

• • • 

• -

• • • - • - - I ·- - • Z::::! • ~~ • • • ~a: 

zw •• • :sa.. • • Q..(/) 5r- - - o...J 

!):LD 

J:u FRANKLIN 

.. • 

.. -

LA GRANGE 

•• ••• 

•• - - - -

ABBOTTSFORD DAM POOL 

a.. 

I I I I I I I I J I I I 

0 10 20 30 40 1 0 20 30 40 1 0 20 30 40 10 20 30 40 

TEMPERATURE, IN DEGREES CELSIUS 

FIGURE 10.-Relation of phytoplankton concentrations to water temperature at sites in West Point Lake. 

50 I I I 

A1 =-0.309 NOV. 16, 1975 A1 =-0.409 MAY 19, 1976 

16.8" c 21.0° c 

25 r- - ._ • • a: 

w I I --. 0 I-

::i 50 a: I I I w ~ A1 =-0.231 DEC. 16, 1975 a.. 13.1° c (/) 25 1- - ~ 

<( 

a: 1------r--· i (.!) • ::i 0 _J 

~50 

~ A1 =-0.669 FEB. 24, 1976 A1 =-1.415 AUG. 10, 1976 

<i 25 

14.3° c 28.3° c 

~ 

z 

w 

~ 0 

0 

a.. 50 I I J: A1 =-0.327 

~ MAR. 22, 1976 A1 =-1.160 

0 25 1-- 14.1° c - a: 

(.!) ... _J I • I <( 0 • 

(.!) 

~50 I I I 

A1 =-0.692 APR. 

20.9° c 

17, 1976 SEPT. 

25.SO C 

10, 1976 j 25 - -

I - l . 00 10 20 30 35 0 10 20 30 35 

DISTANCE DOWNSTREAM FROM FRANKLIN, IN RIVER MILES 

FIGURE 11.-Plots of observed algal growth potential by river mile downstream from Franklin station. 

growth potential was less than about 0.5 mg/ 

L, a decrease in the phytoplankton concentration occurred downstream. Therefore, the availability of nutrients, as indicated by AGP, ap13 

pears to be limiting phytoplankton growth in 

the lower reaches of the lake. 

The rates of change of AGP and phytoplankton concentrations increased with distance for 
11 NOV. 16, 1975 

16.8" c 

) • a: 

~15 I I ::::i 

::::i DEC. 16, 1975 .....J 13.1° c ~10 ra: .. w ,.. a.. 5 l (/) 

::J 15 w I I u FEB. 24, 1976 

d10 

14.3° c -

0 

2 

~ 5 l I 

z 

015 I I-

::.::: MAR. 22, 1976 z 

::i 10 

14.1° c 1-

a.. 

0 

1-

~ 5 _I • a.. 15 

APR. 17, 1976 

20.9° c 

10 

5 

0 20 

J P1=0.025 

cells/mLIRM 

I 

t--

• r--

• 

I 

P1=0.063 

-

• __. 

I 

I 

P1=0.064 

- ... 

I 

P1=0.075 

-

... • l 

P1=0.123 

30 35 0 

I I 

P1=0.075 

• 

l I 

P1=0.164 

I 

10 20 

I 

__._ 

MAY 19, 1976 

21.0° c 1 

• 

JULY 2, 1976 

26.6° c 

• 

AUG. 1C, 1976 

28.3° c 

AUG. 24, 1976 

29.0° c 

SEPT. 10, 1976 

25.6° c I 

·-

• 

• 

30 35 

DISTANCE DOWNSTREAM FROM FRANKLIN, IN RIVER MILES 

FIGURE 12.-Plots of observed phytoplankton concentrations by river mile downstream from Franklin 

station. 

each of the sampling periods and are plotted I 

I against water temperature in figures 13 and · 

14 (Cherry and others, 1978). Both rates increased with increasing temperature greate1· 

than 13°C. 

The relationship between the rate of change 

of AGP and water temperature with river mile 

is defined from about 10oC to 30oC by the following equation : 

A1 =- (0.0673T-0.625), (3) 

where 

A1 =rate of change of AGP per river mile 

in (mg/L) /RM, and 

T=a.verage water temperature, in oc. 

The relationship' between the rate of change 

of phytoplankton concentration and wat,er temperature with river mile is defined from about 

10°C to 30°C by the following equation: 

P1 =0.0084T-0.066, (4) 

where 

14 

_j 

<t: 

i= 

zw UJ.....l 

5~ a.. a: I~ 1.5 

r--

sa:: 

offi 

a::: a.. <.9a:: 

....Jw 

<t:!::: 

<.9....J1.0 ....Ja:: <t:UJ 

u..a.. 

ocn 

w2: 

(.9~ Z(.9 

..:x:-

::I: :::l 0.5 

u~ 

u.. 

0~ 

w 

1-

<t: 

a: 

• 

• 

• 

O.O OL...__ ____ 1.L0-----:'20:------::3:'":0---~40 

TEMPERATURE, IN DEGREES CELSIUS 

FIGURE 13.-Relationship of temperature to the rate of 

change of algal growth potential per river mile. 
•ll '"I"'"' 

••• 1 

·::::w 

~;~ ~ .2Q • 

;;:: 

ca:: 

~::~ 

:;;::: a: 

<:a: 

c .. w .15 ca.. 

1-· 

~: ffi a:~ 

(~::1.10 

ur~ ~~ 

:;;::; ffi <t a.. :I: 

' • .1 (/') 

·~. :::l .05 ""'W 

., u 

:~· ... 

<f 'l: • 

TEMPERATURE, IN DEGREES CELSIUS 

FIGURE 14.-Relationship of temperature to the rate 

of change of phytoplankton concentration per river 

mile. 

P1 =rate of change of phytoplankton concentration per river mile, in (log" 

cellslmL) IRM, 

T=average wate·r temperature, in oc. 

TherefoTe, knowing the AGP and phytoplankton concentrations and the water temperature of the lake, the AGP and phytoplankton concentrati,on can be estimated at downBtream sit,es in the lake using the following 

equations (Che·rry and others, 1978) : 

(5) 

where 

Cm.= AGP in mgiL at river mile R, downstream from Franklin, 

A1 =rate of change of AGP, in (mgiL) I 

RM, 

R =river mile downstream of Franklin, 

amd 

Ca.;= AGP, in mgiL, from Franklin. 

Cpr=( PlR)+Cpi, (6) 

where 

Cpr= phytoplankton concentration in 

(loge) cellslmL at riv·er mile, R, 

downstream from Franklin, 

P1 =rate of increase of phytoplankton concentration, in (loge cellslmL) I 

RM, 

R = river mile downstream from Pranklin,and 

C pi.= phytoplankton concentrations, in 

(loge) cellslmL, at Franklin. 

Figure 15 shows a comparison of calculated 

(equation 2) and observed AGP, and fig·ue 16 

shows a comparison of calculated ( equat!0n 6) 

and observed phytoplankton concentrations for 

each of the sampling periods. The calculated 

concentrations approximate the observed ones. 

Estimated maximum phytoplankton ·concentrations at sites in the West Point L2ke at 

various temperatures are shown in figure· 17. 

At 30°C, a maximum phytoplankton conc~ntration in the lake would occur at the dan1 pool 

with a estimated ·minimum of 47 mgiL AGP 

concentration at Franklin. At 30°C, a maximum phytoplankton concentration would occur at Abbottsford with an estimated minimum 

of 35 mg/L AGP at Franklin. Maximum phytoplankton concentrations, at 30°C, at other upstream sites would occur with lower AGP at 

Franklin. Estimated phytoplankton conc"?.ntrations, at 30°C, and with a 47 mg/L AGP at 

Franklin, would not exceed 7 ,500, 101,000, 

750,000, and 3.5 million cells/mL at Franklin, 

LaGrange, Abbotsford, and the dam pool, 

respectively. 

The analysis of the relation of ·phytoplankton to AGP indicates that at sites where the 

AG P has decreased to less than about 0.5 

mg/L, the phytoplankton concentrations decrease downstream. Where AGP is greater than 

about 0.5 mg/L, phytoplankton concentr?tions 

are dependent on water temperature and distance downstream from Franklin. Wl·~ther 

factors other than AGP would limit phytoplankton growth approaching 3.5 n1illion 

cells/mL could not be determined fro:n the 

data. 

15 

NITRIFICATION 

Nitrification can be an important factor affecting the dissolved-oxygen balance in str~ams. 

The DO balance in the Chattahoochee River 

was determined by Stamer and others ( 1978) 

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

in the reach from Atlanta (RM 302.97) to 

Franklin (RM 235.46). Hourly field measurements at 11 sites were compared with values 

computed (fig. 18) using the method described 

by Velz ( 1970). DO concentration decreases in 
w~----~~--------~~------~~----~ 

251--- i--

NOV. 16, 1975 

16.8° c 

MAY 19, 1976 

21.0° c 

0:: 

w 

1-

--------.__--------- o~----------------------~------~~~-1 ---------------

! :J ~ I 0:: 

(!) 

::::i 

DEC. 16, 1975 

13.1° c 

JULY 2, 1976 

26.6° c 

~ W.-----------------------------------~ 

~ 

.... r 25 ,__ _--f'CALCULATED 

FEB. 24, 1976 

14.3° c 

<( ------

~ OBSERVED?' ---------

AUG. 10, 1976 

28.3° c 

~ 0~---------------------------------=~ 

2 60.---------------------------------~ 

0 ~ 25- 0:: 

MAR. 22, 1976 

14.1° c 

AUG. 24, 1976 

. 29.0° c 

(!) ...._ 

(!) 

~ oc=====~~~~~~-~--_j ~ w.-----------------------------------. ~--!:CALCULATED 

25fAPR. 17, 1976 

20.9° c --------

SEPT. 10, 1976 

25.6° c 

---- ~...a:::,__ 

oC:::~~c=~==~~~===·-4~~~ -- 0 10 20 30 

DISTANCE DOWNSTREAM FROM FRANKLIN, 

IN RIVER MILES 

0 10 20 30 

DISTANCE DOWNSTREAM FROM FRANKLIN, 

IN RIVER MILES 

FIGURE 15.-Comparison of calculated and observed algal growth potential for each sampling r~riod. 

the river w·ere attributed to a combination of 

nitrogenous and carbonaceous oxygen demands. 

Nitrogenous demands (nitrification) caused 

approximately 50 percent of the DO decrease 

in the reach (Stamer and others, 1978) . Figure 

19 shows the DO decrease re"Sulting from nitrificati,on to the total decrease in DO during 

the period of June 1-2, 1977. 

Nitrification or oxidation of NH4 - N to nitrate proceeds in two steps catalyzed by the 

chemoautotrophic bacteria, Nitrosomonas and 

Nitrobacte'r (Alexander, 1964) : 

NH4 + + 1-1/2 0:: N itrosomonas 

N02- +2H+ +H20 

Nitro bacte1· 

---~N03-

The treatment of wastewater reduces the 

carbonaceous oxygen demand because utilizable 

carbon substrates are quickly attacked by many 

heterotrophic bacteria (Strom r.nd others, 

1976). The nitrogenous oxygen demands often 

are not greatly affected during wastewater 

treatment because initially the reaction kinetics of nitrification proceed slowly. As a result, 

nitrification may occur downst':'eam from 

treated wastewater outfalls. 

16 

The mean concentrations of Nitrosomonas 

and Nitrobacter bacteria in the water column 

and benthic sediments during the period June 

1-2, 1977, as determined by Ehlke (1978) are 

shown in figures 20 and 21. 

The N itrosomonas concentration was 10-

100 times greater in the benthic sediment than 

in the water column. This is consistant with 

studies elsewhere (Tuffey and others, 1974; 

Curtis and others, 1975). The J.litrosomonas 

concentration in the water column was the least 

at RM 302.97 but was almost constant .further 
15 

10 I5 a:: 

~ 15 

::J 

3 

i 10 ta: 

w ,..... D.. 

en 5 

..J 

..J 15 w 

u 

"""i 

e, 10 t- 0 

d 

~ 5 z 

~ 15 

~ 

z 

~ 10 t-

~ it 5 

15 

10 

5 

0 

I 

---

I I 

NOV. 16, 1975 

16.8° c 

----------

DEC. 16, 1975 

13.1° c 

CALCULATED~--------=-

---- OBSERVED /f 

FEB.24, 1976 

14.3° c 

MAR. 22, 1976 

14.1° c 

APR. 17, 1976 

20.9° c 

-

-

DISTANCE DOWNSTREAM FROM FRANKLIN, 

IN RIVER MILES 

I I I 

__ .-- -

-----------MAY 19, 197~ 

21.0° c 

JULY 2, 1976 

26.6° c 

AUG. 10, 1976 

28.3° c 

OBSERVED ------- -..--..- --------- AUG. 24, 1976 

"'CALCULATED 29.0° C 

DISTANCE DOWNSTREAM FROM FRANKLitl. 

IN RIVER MILES 

FlGURE 16.-Comparison of calculated and observed phytoplankton concentrations for each sampling pf.riod. 

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~--------------~--------------~---------------L--------------~40100 10 20 30 

DISTANCE DOWNSTREAM FROM FRANKLIN, IN RIVER MILES 

FIGURE 17.-Estimated maximum phytoplankton concentrations at sites in West Point Lake at 

various temperatures. 

17 
14r-~--------~--------~--------~--------~--------~--------~---------, 

13 

12 

c::: 

~11 

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2 

.: . ... 

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e COMPUTED 

• OBSERVED 

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o~3-QLQ _________ 29LQ _________ 28LQ _________ 27LQ _________ 2L6Q---------2~5Q---------2~4Q--------~23Q 

DISTANCE, IN RIVER MILES 

FIGURE 18.-Comparison of computed and observed dissolved-oxygen concentrations in the Atlanta to Franklin reach during low flow period, June 1-2, 1977. 

downstream. This collection site was upstream 

of all facilities in metropolitan Atlanta. Nit·roso'monas concentrations generally were greatest 

near RM 298.77. This site is downstream from 

the two major Atlanta was1tewater treatment 

facilities (RM 300.24 and RM 300.52). Nit?·osomonas concentrations at Capps Ferry Bridge 

(RM 271.19) and Franklin (RM 235.46) were 

also greater than at most other collection sites. 

The concentration of N'itrobacterr in benthic 

sediment was greatest near RM 271.19 and RM 

235.46, approximately 103 per gram. In the 

reach containing municipal point-source discharges (RM 300.52-RM 283.78), concentrations of Nitttobactet· generally were less in 

benthic sediments than elsewhere in the study 

area. The N-itttobactett concentration in the 

water column was nearly constant from RM 

302.97 to RM 235.46. As with other studies 

(Tuffey and others, 1974; Curtis and others, 

1975), the Nit1·obactett ooncentration in benthic 

sediments was 10-100 times greater than in the 

water column. The Nitrobacte1· concentration 

was generally lower than the Nit1·osmnonas 

concentration. 

18 

The observed mean NH4- N, 1'-T02- N, and 

N03 -N concentrations for June 1-2, 1977, are 

shown in ·figure 22. During the June 1-2, 1977, 

sampling period, the concentrationE of NH.1- N 

and N02-N were lowest near RM 302.97. The 

concentration of N0:1 - N, which is the end 

product of nitrification, was about 0.1 mg/L 

at RM 302.97 and increased to about 1.2 mg/L 

at RM 235.46. The concentrations of NH4- N 

and N02 - N increased rapidly downstream 

from the municipal wastewater outfalls. The 

NH.1 - N concentration was maxirnum at RM 

298.77. 

The concentrations of NH4- N decreas.ed at 

almost a constant rate of 0.02 mg/L/h during 

June 1-2, 1977, from RM 298.77 to RM 235.46, 

based on a travel time of 65.07 hand a change 

in concentration of NH-t- N from 1.8 mg/L to 

0.2 mg/L (fig. 22). 

Concentrations of NO:{- N increased at almost 

a constant rate of 0.02 mg/L/h during the 
2.0 r---.--,------.,----.,--,----.,--,-----,-,-----,-,-----,-,------, a: 

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0 :.:-:-:-:-:·:-:·:.:-:·:-:· 

D Total decrease in dissolved oxygen 

!<<<I Decrease in diss?ly~d ~xygen because 

of mtnf1cat•on 

i i o.s ~ : ·•·•·•·•·•·•·•·•·•·1111111111111111 :::.:::·::: ::·.: •. :·: .1· : 11111: t:tt 111~ r :.:::: •......... 

::· ::: :: ~ ............. .................. !11111111! I!! !Ill !I !I! lilillllllil:lil illillll: 11: 

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300 290 280 270 260 250 240 

DISTANCE, IN RIVER MILES 

-

-

-

230 

FIGURE 19.-Comparison of decreases in dissolved oxygen resulting from nitrification to total decrease in dissolved oxygen in the Atlanta to Franklin reach during low flow period, June 1-2, 1977. 

,,__ ·-- I '"""' / --....... I ........ , / ..................... 

/ ................... / Water column/•-- -------------------·-... / 

I 

I 

I 

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I 

I 

J 

286 282 276 271 266 

DISTANCE, IN RIVER MILES 

260 247 235 

FIGURE 20.-Nitrosomonas population in Chattahoochee River water and benthic sediment during June 1-2, 1977. 

19 
286 282 276 271 266 260 247 235 

DISTANCE, IN RIVER MILES 

FIGURE 21.-Nitrobacter population in Chattahoochee River water and benthic- sediment during June 1-2, 1977. 

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-... _;-..... ___ .... ... , NOz-N ......... _.-·-·-·- ',....._ ...... 

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303 299 295 286 282 276 271 266 260 247 

DISTANCE, IN RIVER MILES 

FIGURE 22.-Mean concentrations of ammonium, nitrite, and nitrate in the Chattahoochee Rjver during 

June 1-2, 1977. 

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

RM 246.93. The disappearance of NH4- N was 

approximately equal to the formation of 

NOa-N during the period of June 1-2, 1977, 

from RM 298.99 to RM 246.97. 

Generally, the higher nitrifying-bacteria concentration in riverbed sediments compared 

with that in the water column has led many 

investigators to conclude that most nitrifyingbacteria activity pvobably occurs in benthic 

sediments, not in the water column (Tuffey and 

others, 1974; Matulewich and Firstein, 1978). 

All·sampling for nitrifying bacteria was done 

when the flow of the Chattahoochee River was 

near 1,150 ft3 /s and the m.ean de:')th from RM 

302.97 to RM 258.6-3 was about 1.42 m. Using 

the data of figures 20 and 21, the relative concentrations of Nitrosomonas and 1 Titrobacter in 

a 142-cm water column and 1-cm benthic sediment column can be calculated. J.veraging the 

20 
data, 53 percent of the NitTosomonas is calculated to be in the water column and 47 percent, 

in the top 1 em of benthic sediment. Similarly, 

72 percent of the Nitrobacte1· was pres.ent 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 wa.t~er column, not in the benthic 

s-ediment. 

SUMMARY AND CONCLUSIONS 

For more than ten years, the Advisory Committee on Water Data for Public Use has been 

interested in obtaining information needed for 

planning river basin development. The upp·er 

Chattahooche~e River basin study began April 

1, 1975, and was the second intensive riv,erquality assessment conducted by the U.S. Geological Survey, with the purpose of providing 

demonstration products for management decisions, alternatives for basin dev,elopment, and 

maintenance and improvement of water quality in the upp·er Chattahoochee Rive-r basin. 

The biological and associated chemical data 

were collect•ed from October 1975 through September 1976 at selected stations in Lake Sidney 

Lanier, West Point Lake, and the Chattahoochee River. 

Phytoplankton c~oncentrations ( cells/mL) 

were generally highe·r downstream from Atlanta than upstream. The highest concentrations (mostly blue-green algae) occurred in 

West Point Lake with an average of 90,000 

cells/mL for the sampling period. The lowest 

concentrations occurred upstream of Lake 

Sidney Lanier (1,000 cells/mL). Concentrations downstream from Lake Sidney Lanier 

were less than 1,800 cells/ mL. The dissolved 

P04- P concentrations were highest in the river 

reaches and upper reaches of the two lakes, 

and lowest at the dam pools of both lakes. This 

was also true for the dissolved N02 + N03- N 

concentrations. AG P was highest downstream 

from Atlanta and lowest in the headwaters and 

at the dam pools in both lakes. Analysis of data 

collected in the W·est Point Lake during sampling periods indicates that AGP decreases in 

respons•e to increases in phytoplankton concentration from the upper to lower reaches of the 

lake. AG P and phytoplankton concentration 

changes are greater at highe-r temperatures 

than at lower ones. Little or no decrease in the 

AG P or increase in phytopl·ankton concen21 

tration occurs with distance at temperatures 

less than about 13 oc. Analysis of the data indicates that phytoplankton concentration is related to water temperature and location in the 

lake at sites where AGP is greater than about 

0.5 mg/L. Phytoplankton concentration decreases downstr·eam in the lake at sites where 

AGP is less than 0.5 mg/L. 

Concentrations of NitTosomonas in the water 

column and .in the benthic sediment increased 

in the reach RM 302.97 to RM 298.99, ard decreased from RM 298.99 to RM 235.46 during 

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

bacteria were present in greater concentrf.tions 

in the benthic sedim·ent than in the water column on a number-p·er-milliliter or per-gram 

basis. If the entire water column (1.4 m) were 

considered, the total number of nitrifying bacte-ria was grea.ter in the water columnthaninthe 

top 1 em of benthic sediment. It is probable that 

most nitrifying-bacteria activity would occur in 

the water column rather than in the benthic 

sediment of the Chattahoochee River. The rate 

of NH1- N disap,pearance (0.02 mg/L/h) was 

approximately equal to the formation of 

NOa- N during the period of June 1-2,1977. 

REFERENCES CITED 

Alexander, M., 1964, Introduction to soil microbiology: 

New York, John Wiley and Sons, 472 p. 

Brown, Eugene, Skougstad, M. W., and Fishman, M. J., 

1970, Methods for collection and analysis of water 

samples for dissolved minerals and gases: U.S. 

Geological Survey Techniques Water Resources 

Investigations, Book 5, Chap. A1, 169 p. 

Cherry, R. N., Lium, B. W., Shoaf, W. T., St.".mer, 

J. K., and Faye, R. E., 1978, Effects of nutrients 

on algal growth in West Point Lake, Georgia: 

U.S. Geological Survey Open-File Report 78-976, 

21 p. 

Curtis, E. J. C., Durrant, K., and Harman, M. M. I., 

1975, Nitrification in rivers in the Trent Fasin: 

Water Research, Vol. 9, no. 3, p. 255-268. 

Ehlke, T. A., 1978, The effect of nitrification O"" the 

oxygen balance of the upper Chattahoochee River, 

Georgia: U.S. Geological Survey Open-File RP-port 

98-973, 19 p. 

Greene, J. C., Miller, W. E., Shiroyama, T., and Maloney, T. E., 1975, Utilization of algal assays to 

assess the eff·ects 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. 

Greeson, P. E., Ehlke, T. A., Irwin, G. A., Limn, B. 

W., and Slack, K. V., 1977, Methods for collection and analysis of aquatic biological and microbiological samples: U.S. Geological Survey Tech-
niques Water Resources Investigations, Book 5, 

Chap. A4, 332 p. 

Hines, W. G., McKenzie, S. W., Richert, D. A., and 

Rinella, F. A., 1977, Dissolved-oxygen regimen of 

the Willamette River, Oregon, under conditions of 

basinwide secondary treatment: U.S. Geological 

Survey Circular 715-1, 52 p. 

Matulewich, V. A., and Finstein, M. S., 1978, Distribution of autotrophic nitrifying bacteria in a polluted river (the Passaic): Applied and Environm.ental Microbiology, v. 35, p. 67-71. 

Metropolitan Atlanta Water Resources Study Group, 

1976, Metropolitan Area, Water Supply R~eview 

Supplement. 

Metropolitan Atlanta Water Resources Study Group, 

March 1977, Third progress report from the Atlanta Water Resources Study Group, 11 p. 

Miller, W. E., Greene, J. C., and Shiroyama, T., 1975, 

Applications of algal assays to define the effects 

of wastewater effluents upon algal growth in multiple use river: Biostimulation and rutrient assessment, U.S. Environmental Protection Agency, 

Corvallis, Oregon, p. 77-92. 

Stamer, J. K., Cherry, R. N., Faye, R. E., and Kleckner, R. L., 1978, Magnitudes, natrre, and effects 

of point and non point discharges in the Chattahoochee River basin, Atlanta to West Point Dam, 

Georgia: U.S. Geological Survey Water-Supply 

Paper 2059. (In press). 

Strom, P. F., Matulewich, V. A., and Finstein, M. S., 

1976, Concentrations of nitrifying tfl.cteria in sewages, effluents, and a receiving stream and resistance of these organisms to chlorination: Applied 

and Environmental Microbiology, v. 31, p. 731-737. 

Tuffey, T. J., Hunter, J. V., and Matnlewich, V. A., 

1974, Zones of nitrification: Water Resources Bulletin, v. 10, p. 555-564. 

Velz, C. J., 1970, Applied stream sanitation: New York, 

John Wiley and Sons, 619 p. 

i::l U.S. Government Printing Offi-:e: 1979-281-359/7 

22