WATER POLLUTION CONTROL RESEARCH SERIES • 16080 — 11;
Induced Aeration
of Small Mountain Lakes
U.S. ENVIRONMENTAL PROTECTION AGENCY
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research. Reports describe the results and
progress in the control and abatement of pollution in our Nation's waters.
They provide a central source of information on the research, development,
and demonstration activities in the Water Quality Office, in the Environ-
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directed to the Chief, Publications Branch,(later), Eesearch Information
Division, MM, Environmental Protection Agency, Washington, D. C. 2C460.
- about our cover
The cover illustration depicts a city in which man's activities coexist in
harmony with the natural environment. The National Water Quality Control
Research Program has as its objective the development of the water quality
control technology that will make such cities possible. Previously issued
reports on the National Water Quality Control Research Program include:
Report Number Title
16080 06/69 Hydraulic and Mixing Characteristics of Suction Manifolds
16080-—10/69 Nutrient Removal from Enriched Waste Effluent by the
Hydroponic Culture of Cool Season Grasses
16080DRX10/69 Stratified Reservoir Currents
16080 11/69 Nutrient Removal from Cannery Wastes by Spray Irrigation
of Grassland
16080D0007/70 Optimum Mechanical Aeration Systems for Rivers and Ponds
16080DVF07/70 Development of Phosphate-Free Home Laundry Detergents
16080 10/70 Induced Hypolimnion Aeration for Water Quality Improve-
ment of Power Releases
16080DWP11/70 Induced Air Mixing of Large Bodies of Polluted Water
16080DUP12/70 Oxygen Regeneration of Polluted Rivers: The Delaware River
16080FY.A03/71 Oxygen Regeneration of Polluted Rivers: The Passaic River
16080GPF04/71 Corrosion Potential of NTA in Detergent Formulations
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INDUCED AERATION OF SMALL MOUNTAIN LAKES
by
Robert S. Kerr Water Research Center
Post Office Box 1198
Ada, Oklahoma 74820
for
ENVIRONMENTAL PROTECTION AGENCY
Project #16080
November 1970
For sale by tho Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price C5 cents
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EPA Review Notice
This report has been reviewed by the Environmental
Protection Agency and approved for publication. Ap-
proval does not signify that the contents necessarily
reflect the views and policies of the Environmental
Protection Agency, nor does mention of trade names
or commercial products constitute endorsement or
recommendation for use.
ii
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ABSTRACT
Summer stratification in small mountain trout-fishery lakes restricts
trout habitat to the thin layer of surface waters. As atmospheric tempera-
tures increase during later summer months, the epilimnion waters reach
temperatures intolerable for trout. A technique of managing trout-fishery
lakes, through introduction of compressed air, was studied at Lake Roberts
in southern New Mexico during the summer of 1969. Research findings and
further research required for optimum development of induced aeration sys-
tems as management tools for trout-fishery lakes are discussed.
iii
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TABLE OF CONTENTS
Section Page
I. Conclusions 1
II. Recommendations • 3
III. Introduction 5
IV. Procedures and Equipment 11
V. Operation Phase 15
VI. Discussion 25
VII. Acknowledgments 45
VIII. References 47
IX. Appendices 49
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LIST OF FIGURES
Figure Page
1. Vicinity Map 6
2. Project Location and Hydrographic Map . 8
3. Area-Capacity Curve 9
4. Air Distribution System 12
1 ?
5. Air Filter and Monitoring Equipment
6. Stratification Before Aeration 16
7. Background Dissolved Oxygen 17
8. Effects on Dissolved Oxygen 18
9. Temperature Changes 20
10. Effects of Aeration on Temperature 21
11. Algal Mats in Coves 23
12. Floating Algal Scum Near Aerator 23
13. Average Dissolved Oxygen Saturation .... 26
14. Effects on pH 27
15. Effects on Hydrogen Sulfide 29
16. Elongated Air Plume 3.0
17. Erupting Bubbles in Air Plume 30
18. Effects on Ammonia-Nitrogen 31
19. Effects on Total Kjeldahl Nitrogen 32
20. Effects on Total Phosphate 34
21. Effects on Ortho-Phosphate 35
22. Effects on Manganese. 36
23. Aeration Effects on Dissolved Oxygen 38
24. Aeration Effects on Stability 41
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LIST OF TABLES
Table Page
I. Hydrologic Data 7
II. Dissolved Oxygen Uptake Test 39
III. Comparison of Various Destratification Efficiencies. ... 43
vii
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SECTION I
CONCLUSIONS
Induced aeration research, described in this report, clearly showed that
complete thermal destratification of small mountain lakes can be accom-
plished with a diffuser-type aeration system such as that used in this
study. Destratification can be maintained with continuous aeration at low
energy requirements at the expense of continually increasing the temperature
of the water mass. Restratification develops rather quickly, however,
when induced aeration is stopped.
Dissolved oxygen (D.O.) can be increased to more than 100 percent saturation
in the hypolimnion due to circulation of highly saturated surface waters.
The increase in D.Ov in the hypolimnion is accompanied by a decrease in
the epilimnion.
High concentrations of hydrogen sulfide (ELS) in the hypolimnion can be
quickly vented to the atmosphere through tne plume of rising air bubbles
above the air distribution system without adverse effects to the aquatic
life or increasing concentrations of "FLS in the surface waters.
High concentrations of phosphates and nitrogen forms in the lower depths
are drastically reduced during induced aeration without significant increases
in the surface waters.
Certain metallic ions such as boron, iron, manganese, aluminum, and strontium
are separated out of the bottom muds and increased in the entire water mass
by as much as ten orders of magnitude by the circulation and mixing action
of induced aeration. Bottom deposited organic material may also be circu-
lated throughout the water mass to exert a significant oxygen demand.
Algal blooms in progress are not retarded by destratification as reported
by others, but, in fact, may be slightly accelerated through an increase
in nutrients within the photic zone. If large algal concentrations die-off
during aeration, thermal destratification can occur without an increase in
dissolved oxygen.
Induced aeration systems can be an effective management tool in trout fishery
lakes. A large increase in habitable water resulted from induced aeration
as shown by the redistribution of fish vertically and horizontally.
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SECTION II
RECOMMENDATIONS
Certain aspects of induced aeration systems used as trout fishery management
tools should be further investigated. Methods for controlling the increase
in water temperature during destratification should be studied. These
studies should include refrigerated air systems and mechanical systems
which circulate the hypolimnion water only. Effects of various systems
on the biological community should be investigated.
Aeration systems should be designed so that water withdrawn from the
hypolimnion is carried to the surface at velocities low enough that sediment
and organic materials are left undisturbed on the lake bottom. Investigations
should also be made as to the feasibility of purposely inducing air to cir-
culate organic bottom materials as a water quality management technique.
Circulation of organic material in early spring could satisfy the oxygen
demand prior to stratification. Aeration on a regular basis over a period
of years should oxidize essentially all bottom organic material, allowing
aeration during summer stratification to increase oxygen in hypolimnion
waters at a greater rate.
Algal control techniques should be developed to retard blooms prior to and
during operation of induced aeration systems. Algalcides should be tested
to develop technology in algal management. Dosage, frequency of dosage,
tolerance of fish to dosage, and long-range effects on water quality from
algal treatment should be investigated.
Studies should be undertaken to compare destratification systems utilizing
air with pure oxygen systems. These studies should relate to oxygenation
efficiency, effects on water quality, and economics.
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SECTION III
INTRODUCTION
The influence of thermal stratification in reservoirs on water quality has
been given much attention in the past five years. Several methods of mod-
ifying thermally stratified reservoirs are being researched (1,2,3,4,5,6,7).
These include discharges from multiple elevations in reservoirs (8), me-
chanical pumping of hypolimnion waters to the surface (9), and release of
compressed air or pure oxygen near reservoir bottoms at different rates
using various arrangements and types of distribution devices (3).
Induced aeration research was begun by the National Water Quality Control
Research Program, Robert S. Kerr Water Research Center, in 1967 using com-
pressed air diffuser systems (10,11,12). The objective of this research
was to develop a system that could be used in small-to-moderate size reser-
voirs to mix the hypolimnion and epilimnion waters. Through the mixing
process, the entire volume of water would become more useful. Anaerobic
conditions could be halted in the hypolimnion and the chemical reduction
process would be altered, resulting in reduced concentrations of sulfides,
phosphates, nitrates, and other nutrients in the hypolimnion waters. The
mixing process would provide greater volumes of improved quality for mu-
nicipal and industrial uses and fish habitat, thereby increasing the value
of these water resources. Mixing of the entire volume of the impoundment
or localized mixing upstream of dams, depending upon the reservoir require-
ments, would improve the quality of release waters withdrawn from lower
levels during power generation. Aeration of hypolimnion waters would create
a greater potential for downstream flow augmentation by allowing waste
assimilation to be accomplished with a higher quality release water—thereby
requiring less water to accomplish the same assimilation results, thus
conserving impounded water for other uses.
In 1969, the New Mexico Department of Game and Fish requested assistance
of the Kerr Research Center personnel in studying destratification systems
as a management tool in their mountain trout fishery lakes. The lake selected
for study was Lake Roberts in southwestern New Mexico where annual fish
kills had occurred as a result of summer stratification, depleting the dis-
solved oxygen at lower depths and restricting the trout to surface waters
where temperatures were too high for survival. Lake Roberts is managed as
a rainbow trout fishery lake on a put-and-take basis since the waters are
too warm for reproduction. The lake is stocked before the start of the
fishing season each spring. The total annual stocking is approximately
17,500 fingerlings and 25,000 catchable-size trout of 9 inches or larger.
The fish are released at different times of the year with 3,500 being re-
leased in April, May, and June; 1,050 in July and August; 1,900 in September;
and 1,750 in October, November, December, January, February, and March.
Lake Roberts is located on Sapillo Creek on the western slope of the Continental
Divide near Silver City, New Mexico (Figure 1). The spillway and normal
lake surface is located at an elevation of 6,035 mean sea level (msl). The
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^SILVER CITY
MEXICO
FIGURE I - VICINITY MAP
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lake is 30 feet deep near the dam, covers an area of about 70 acres, and
has a volume of approximately 1,000 acre-feet at the spillway crest (Figures
2 and 3). The lake was built in 1963 by the Game and Fish Department and
is fed by subsurface springs in the upper reaches which had total discharges
of about 1 cfs before they were submerged.
Sapillo Creek, dry most of the time upstream of the lake except during
local heavy rainstorms in late summer, drains 5,372.0 acres of forest and
range land. The upper reaches of Sapillo Creek are primarily range land
and used for cattle grazing. The lower portion of the drainage above the
dam is in the densely forested Gila National Forest. General hydrologic
data are presented in Table 1.
TABLE I
HYDROLOGIC DATA
Meterologic
Condition
Dry Year
Average Year
Wet Year
Average Annual
Precipitation
Inches
9.84
16.20
27.48
Average Annual
Evaporation
Inches
81
51
29
Average Annual Runoff
to Lake Roberts
Acre-Feet
882
3,265
11,095
The objective of the Water Quality Control Research Program in this study
was to study the dynamics of an induced air system in a small reservoir
for comparison with the effects of previous large reservoir studies. The
objective included evaluation of changes in selected chemical parameters
throughout the water mass, resulting from two periods of induced aeration
separated by a restratification period. Chemical changes resulting from
destratification with an air distribution system of the proposed type had
not been evaluated in prior studies. In addition to chemical quality changes,
aeration efficiency in terms of pounds of dissolved oxygen pumped per
horsepower-hour, vertical oxygen distribution, and saturation changes as
well as economics were to be evaluated.
The New Mexico Game and Fish Department's interest in induced aeration was
to utilize existing aeration technology to develop an induced aeration system
as a useful tool in fisheries management. The primary factors proposed for
evaluation were change in occupancy of fish habitat, reduction in seasonal
stress factors, and comparison of long-range increases in fish productivity
resulting from nutrient circulation by induced aeration during critical
summer months. Biological data collected by the New Mexico Game and Fish
Department are not included in this report.
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- Sornpl* Point* ( Ouoy Slot Ion i)
Contour Inttrvol 5ft.
Nott:Surv*r mod* prior to irtlHol filling
FIGURE 2 - PROJECT LOCATION AND HYDROGRAPHtC MAP
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li.
I
5 6012
?
6O08
6004
6000
6998
5996
6000
6005
601 0
6015
6020
6025
6030
6035
6032
6O28
6024
6020 ]•-
6016
320
400
480 560 640
CAPACITY - ACRE-FEET
720
800
880
96O 1040
FIGURE 3 — AREA - CAPACITY CURVES
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SECTION IV
PROCEDURES AND EQUIPMENT
The project plan consisted of five sequential phases, exclusive of equip-
ment assembly and installation. Phase I consisted of background monitoring
during the normal spring stratification period. Samples for chemical
analysis were collected as well as determination of vertical profiles of
temperature and dissolved oxygen. After stratification had reached a static
condition, Phase II was initiated, which involved the operation of the
aeration equipment and monitoring the progress of destratification.
When the lake reached an isothermal condition and the selected chemical
parameters had reached stability, the lake was allowed to restratify during
Phase III. During the restratification phase, monitoring of temperature,
D.O., and chemical parameters was continued. When the lake had restratified,
Phase IV was initiated consisting of once again operating the aeration
system and monitoring the occurrence of destratification. Phase V con-
sisted of monitoring restratification after aeration was halted. This
monitoring continued until after the normal fall overturn.
During the background monitoring of Phase I, the New Mexico Game and Fish
Department determined the vertical and horizontal distribution of fish
and phytoplankton. These studies were repeated regularly during the first
aeration phase to determine the depth and lateral extent of improved hab-
itat resulting from destratification.
The air distribution system was assembled on the lake shore on June 14
(Figure 4). The design of the air distribution system was a modification
of the system used in Eufaula Reservoir during the summers of 1967 and 1968,
The distribution manifold was constructed from two 40-foot lengths of
4-inch diameter aluminum pipe, joined with a tee connector. The pipes
were plugged on the ends and each 40-foot section had eight equally spaced
upright microporous diffusers. The diffusers were commercially fabricated
porcelain, hollow candles with bubble-forming capilliaries of 25 x 10 cm
average radius. The manifold was supported on six A-frame legs, 2.5-foot
high, to allow distribution of air above the mud-water interface on the
bottom. The manifold was anchored to the bottom at a depth of 30 feet,
approximately 150 feet upstream of the dam with the piping placed parallel
to the longitudinal axis of the lake. The air supply source was a diesel-
powered air compressor. Air was piped from the compressor ^through a filter
for oil removal and then through a volume gauge. Pressure and temperature
gauges were attached to the air discharge pipe at the exit from the filter
(Figure 5). Air was supplied to the distribution manifold through two
300-foot lengths of 3/4-inch standard quick-coupling air compressor hose
connected to the volume gauge.
Assembly of the distribution system was completed on June 14, and the system
was installed on June 15. The manifold was floated to the pre-selected
location with air being pumped through the system by the compressor for
floatation. When the manifold was in the correct position, the compressor
11
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Figure 4 - Air Distribution System
Figure 5 - Air Filter and Monitoring Equipment
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was stopped and the manifold was flooded with water and lowered to the
bottom with lines from anchored boats. The system was anchored to the
bottom by divers.
Five sampling stations were located for monitoring changes in water quality
parameters during the project (Figure 2); these stations were permanently
marked by buoy installations. Samples were collected from three depths
or at 5-foot intervals at these stations for analyses of the various chemical,
physical, and biological parameters. Sample analyses for sulfide, D.O.,
temperature, pH, and conductivity were made in the field. Samples for
the other parameters were ice-packed or chemically fixed following col-
lection and flown to the Robert S. Kerr Water Research £enter for analysis
(Appendix Table 1).
Dissolved oxygen was measured in situ at 5-foot depths using a battery-powered
Weston and Stack Dissolved Oxygen Analyzer, Model 300, equipped with Model A-15
DC-powered sampler. This equipment was routinely checked and adjusted
against the standard Winkler Method using the azide modifications. The
oxygen analyzer was equipped with temperature readout which was used for
collecting temperature data at 5-foot depths. Conductivity and pH data
were collected in the field using battery-powered pH and conductivity meters.
The trace metal analyses, recorded in Appendix Table 2, were made by emission
spectroscopy of nitric acid fixed samples. These samples were concentrated
by evaporation by heating to a temperature just below the boiling point.
The samples were concentrated to contain approximately the same dissolved
solids as standards. A volume of the sample was analyzed using the rotating
disc attachment in conjunction with a direct reading emission spectograph.
All other samples were chemically analyzed according to procedures of the
Federal Water Pollution Control Administration Methods for Chemical Analysis
of Water and Waste, November 1969 (13).
13
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SECTION V
OPERATION PHASE
Phase I
Field activities were initiated by collecting background samples from
Stations 1, 2, and 3 at Lake Roberts on May 22, 1969. Temperature and
D.O. were measured at 5-foot intervals, and it was observed that the lake
had begun to stratify. Hydrogen sulfide had formed in the lower depths
while an algal bloom had developed. The thermocline had become well es-
tablished at a depth of 13-18 feet with zero mg/1 (milligrams per liter)
D.O, below 20 feet near the dam (Figures 6 and 7).
Sampling stations were monitored again on June 15 prior to the start of
aeration. Data collected showed the lake had stratified to even shallower
depths (12-16 feet) since the May sampling. Oxygen had become completely
depleted below 16 feet (Figure 7). Using the area-capacity curve (Figure 3)
constructed from the hydrographic map (Figure 2), it was determined that
about 25 percent of the volume had less than 4.0 mg/1 D.O. The bottom
water layers near the mud-water interface had 2.6 mg/1 ^S, while the
upper half of the water column had about 0.4 mg/1 which was approaching the
toxic level for rainbow trout.
Other parameters such as ammonia nitrogen, total Kjeldahl nitrogen, manganese,
total phosphate, ortho-phosphate, pH, specific conductance, and total iron
showed significant stratification and indicated a very anaerobic environment
in the lower depths. The algae bloom identified as Anabaena Spiroides had
completely developed by mid-June, forming a thick "pea soup" scum over the
entire lake surface during the late evening through the early morning hours.
Phase II
The first aeration test was started at 12 noon on June 16, 1969. Air was
supplied to the distribution system at the rate of 100 cfm (corrected for
altitude and temperature) with a pressure of 34 psig at the flow meter.
Compressor performance, compressed air flow rate, air flow temperature,
and pressure were recorded four times daily. The compressor was operated
continuously except for periods of approximately ten minutes when it was
stopped for servicing and refueling.
During the first aeration phase, the lake was monitored at Stations 1
through 4 for D.O., temperature, conductivity, pH, and ^S each morning
and afternoon to detemine the radiating effects of aeration. D.O. and
temperature profiles were measured at 5-foot intervals from surface to bottom.
After three days of continuous aeration, the entire lake volume reached a
minimum of 6.0 rag/1 D.O. (Figure 8). The H2S had disappeared and all
measured chemical parameters indicated complete mixing. Temperature changes
15
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I I
10 15
Temp-°C
Scale: l"= 500'
MAY 22,1969
JUNE 15,1969
FIGURE 6 - STRATIFICATION BEFORE AERATION
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UJ
UJ
u.
I
I
I-
o.
UJ
o
MAY 22, 1969
JUNE 13, 1969
28
Scale: l"= 400'
FIGURE 7 - BACKGROUND DISSOLVED OXYGEN
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NORMAL
STRATIFICATION |
AERATION
^~ RESTRATiFICATION
/ I AERATION
RESTRATIFICATION
TURNOVER
LU
LU
li.
I
I-
(X
Ul
o
20
MAY
10 2O 3O
JUNE
10 20 30
JULY
1969
10 20
AUG.
30 10
20 30
SEPT.
LEGEND
— D.O. > 4.0 mg/l
- D.0.< 4.0>0.0mg/ I
£* — D. 0. = 0.0 mg/l
FIGURE 8- EFFECTS ON DISSOLVED OXYGEN
18
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were significant during the first three days of aeration (Figure 9). Thermal
stratification was destroyed during three days of aeration and the lake
became isothermal. Injection of warm compressed air resulted in raising
the temperature of the entire water mass to temperatures near those
of the surface waters prior to destratification (Figure 10).
Fish distribution studies conducted by the New Mexico Game and Fish
Department showed that before mixing fish were well distributed horizontally
but restricted to the upper 12 feet of water depth by the oxygen-void
hypolimnion. Fishing prior to aeration had been relatively poor. After
the first day of aeration, fishing was greatly improved with most anglers
taking their daily limits. The distribution was significantly changed
with greatest concentrations of fish near the aerator at all depths.
Station 2, approximately 1,100 feet upstream of the aerator, had fish to
depths of 20 feet after the first day of aeration. However, after the
third day of aeration, fish were equally distributed at all depths through-
out the water mass.
Destratification effects during the first aeration tests were significant
since it was the first time 100 percent oxygen saturation had been reported
at all depths in similar aeration tests. Even though all parameters im-
proved in the hypolimnion during aeration, the concentration of algae con-
tinued to increase reaching nuisance bloom proportions. Algae began to
concentrate, forming thick mats on the surface during the night and early
morning hours, thus reacting contradictory to the findings reported by
Robinson (14).
Phase III
After seven days of continuous aeration, the lake was allowed to restratify
(Figures 8, 9, and 10). During the restratification period, the air dis-
tribution system was modified for a second induced aeration test. Modi-
fication of the air distribution system was accomplished by divers who
disconnected the manifold at the tee and plugged off one branch of the
tee allowing compressed air to be released through only half the distribution
system. An additional buoy station (Station 5) was added to the existing
four sampling stations to have more comprehensive coverage o;f restratification
rates.
Twice a day monitoring of D.O., temperature, pH, conductivity, and l^S was
continued at the five stations through the restratification period to determine
the rate of reformation of the hypolimnion and HLS buildup.
Chemical samples from Stations 1,2, and 3 were collected at the surface,
mid-depth, and bottom at 8-day intervals during restratification. The
chemical parameters sampled were the major nutrients measured during the
first aeration test (Appendix Table 1). Analysis of these samples indicated
an increased concentration of chemical nutrients in the bottom waters by
the end of the restratification test.
19
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FIGURE 9 - TEMPERATURE - CHANGES
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NORMAL STRAT.
/-AERATION
/ ^RESTRATIFICATION
'I 7 | AERATION
RESTRAT.
TURNOVER
UJ
ID
I
i
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
2O°C
_L
> 22 °C
22 °C
_L
STATION NO.
_L
30 10 20 30
MAY JUNE
10
20 30
JULY
10
20 30
AUG.
10 20
SEPT.
FIGURE 10 - EFFECTS OF AERATION ON TEMPERATURE
21
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Seventeen days of restratification resulted in the hypolimnion reforming
below a depth of 12 feet. The lake had zero mg/1 D.O. below 12 feet
(Figure 8); the thermocline had reformed; and algae continued to form
thick, blue-green mats on the surface resulting in blankets of floating
algae in the coves (Figures 11 and 12).
Phase IV
The second induced aeration test was started on July 10, 1969, with air
being pumped at 54 cfm, creating a pressure of 22 psig in the discharge
hose at the lake shore. Except for service and fuel stops, aeration was
continuous until July 19 when aeration was halted for four days due to
mechanical problems. Aeration was started again on July 23 and continued
through August 23 without further interruption.
Monitoring of aeration effects was continued as scheduled for the first
aeration test with the exception that Station 5 was included for measure-
ment of D.O., temperature, pH, conductivity, and H-S to allow a more ac-
curate determination of radial aeration effects. Major chemical nutrients
were measured 6 and 24 days after the start of the second aeration test.
Increases in D.O. began to appear in the mid-depths with 4.0 mg/1 reaching
a depth of 15 feet after only 24 hours of operation. After two days of
continuous aeration, it was noted that oxygenation conditions were begin-
ning to degenerate. The degeneration of the rate of oxygen absorption was
first noticed after two days of constant cloud cover and after an intense
cold rain during the second night, which caused a high discharge through
the uncontrolled spillway, carrying much of the surface-floating algae
downstream. The day following the rainstorm the algal mats had disappeared,
there appeared to be very little plankton in the water mass, and fish began
to stress. Anaerobic conditions continued to become worse and fish began
to die even though aeration was continuous. Induced aeration was continued
in order to satisfy the oxygen demand more quickly so that restocking could
be done without undue loss of time.
After the algae died, a tremendous oxygen demand was established as a result
of the decomposing organic material. Continued aeration could not immediately
satisfy the oxygen demand. During the four-day period, when the compressor
was stopped for repair, the organic material in suspension began to settle
to the bottom and D.O. in the surface waters began to improve. However,
when aeration was started the second time on July 23, circulation of water
mixed the bottom organic material back into the water mass and caused a
temporary loss of oxygen until the oxygen demand became satisfied. This
phenomenon was found to have occurred in aeration studies in a small lake
near Stockholm and is discussed by Bernhardt, 1967 (15).
By July 27, the oxygen demand had begun to become satisfied and had increased
to 7.0 to 8.0 mg/1 D.O. at the surface with 4.0 mg/1 reaching a depth of
22 feet (Figure 8). The decision was made to restock the lake with rainbow
trout at this time. Approximately one-third of the normal concentration of
catchable-size trout was restocked on July 29, of which about two-thirds
survived. The one-third loss of restocked fish apparently was caused by
22
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Figure 11 - Algal Mats in Coves
Figure 12 - Floating Algal Scum Near Aerator
23
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the unavoidable shocking of the fish with the quick change in temperature.
The lake was about 24°C, and the water in the transport truck was approxi-
mately 18°C. Within two days after restocking, the D.O. in the surface
waters began to degrade again. This degradation was apparently a result
of the decaying dead fish on the bottom disrupting the delicate balance
of aerobic-anaerobic conditions, causing the lake to return to an anaerobic
environment.
Aeration was continued until August 26 with a gradual increase in D.O. in
the surface waters reaching 6.0 mg/1 at depths of 10 feet and 2.0 mg/1
at 20 feet. Aeration was discontinued prior to complete oxygen saturation
of the entire water mass as in the first test in order to allow enough
time remaining in the summer season to remeasure the second restratification
rate.
Phase V
Aeration was stopped on August 26, and the lake was allowed to partially
restratify before normal fall "turnover" (Figure 9). The normal fall
"turnover" occurred in Lake Roberts during the first week of October with
D.O. reaching concentrations of 7.0 to 5.0 mg/1 throughout the water mass
by October 15.
Dissolved oxygen and temperature profiles were monitored on August 27, 29,
and 30; September 10; and October 15 during the restratification and
"turnover" period. Chemical restratification during Phase V reached a
maximum around September 10 with 4.0 mg/1 D.O. at a depth of 10 feet and
less than 1.0 mg/1 below that depth. The temperature profiles indicated
only slight restratification in the upper 8 feet of the lake (Figure 9).
By October 15, the normal seasonal "turnover" was complete and the lake
had become well mixed to an isothermal condition at a temperature of 14.2°C
and with 8.0 mg/1 D.O. to depths of 30 feet.
Chemical samples were collected at Stations 1, 2, and 3 after the "turnover"
period for comparison with the previous four phases of study (Appendix Table 1),
Analyses of these samples indicated the lake had become well mixed chemically
as a result of the seasonal "turnover."
Lake Roberts was restocked in mid-October with approximately 17,000
fingerling and 8,000 catchable-size rainbow trout without adverse effects.
24
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SECTION VI
DISCUSSION
Literature, reporting reservoir destratification and induced aeration in
small lakes, indicates little research has been done to characterize the
changes in major chemical nutrients resulting from induced aeration. Pri-
mary evaluations of the magnitude of changes in selected chemical parameters
in epilimnion and hypolimnion waters, resulting from induced air mixing
and introduction of dissolved oxygen, were specific goals of the research
conducted by the Robert S. Kerr Water Research Center.
In addition to measuring chemical parameters, evaluations of energy
requirements and oxygenation efficiency to maintain the lake in a well-mixed
isothermal state were also studied. Energy requirements and oxygenation
efficiency were then compared to previous studies to determine the system's
potential as a water quality management tool.
A host of chemical parameters was measured during each of the five phases
of operation (Appendix Tables 1 and 2). Pertinent parameters tabulated in
Appendix 1 are illustrated graphically and discussed in this section.
Several parameters were not measured throughout all phases of the study
when it was found that they were not significantly affected by aeration.
At the beginning of aeration, the lake was in a strongly stratified condition
with D.O. in the epilimnion in a super-saturated state as a result of photo-
synthetic activity of algae (Figure 13). It became obvious after seven
days of aeration that the stratified condition had been destroyed and
super-saturated epilimnion water had mixed with the anaerobic hypolimnion
waters, creating a well-mixed water mass with 100% oxygen saturation on
the bottom. During the second phase of the study when restratification
was allowed, the lake restratified again forming an anaerobic environment
in the hypolimnion and a super-saturated epilimnion. During the second
aeration phase, an algae die-off occurred resulting in an almost complete
loss of oxygen as a result of mixing the decaying organic material precip-
itated by the dead algae. This condition was partially overcome by continued
aeration, and the lake was restocked at an inopportune time before restoration
was complete. The death of part of the restocked fish upset the balance
of the lake once again and it became anaerobic. Continued aeration finally
restored the lake to near its original state, and aeration was halted to
allow measurements of a second restratification phase. Monitoring was
continued through the normal seasonal "turnover" for comparison of restrati-
fication conditions.
Measurements of pH also illustrate very remarkably the effects of mixing
by aeration. The pH returned to high values in the bottom and low values
at the surface during restratification and quickly responded to mixing during
the second aeration test (Figure 14). It was noted that during the second
aeration test when the algae died and the lake became anaerobic, the pH
typically dropped to values below 8,0 throughout the water mass. During
25
-------
FIGURE 13 - AVERAGE DISSOLVED OXYGEN SATURATION
-------
AERATION <» ^RESTRATIFICATION
NORMAL STRAT. \'\ 7 I AERATION
RESTRATIFICATION
x
a
I
a.
9.2
9.0
8.8
8.6
8.4
8.2
8.0
7.8
7.6-
7.4
9.2
9.0
8.8
8.6
8.4
8.2
8.0
7.8
7.6
7.4
STATION NO.
I I
LEGEND
SURFACE
BOTTOM
STATION NO. 2
I
I
I
I
I
10 20 30
JUNE
10 20 30
JULY-1969
10 20
AUG
30
10 20
SEPT
FIGURE 14- EFFECTS ON pH
27
-------
the 4 1/2 day compressor-repair period, pH showed a quick response to
restratification as particulate matter held in suspension by aeration
began to settle to the bottom.
Hydrogen Sulfide increased significantly in the bottom near the mud-water
interface as the lake stratified during early June (Figure 15). However,
when aeration began, H_S disappeared in the water mass by the second day.
During the first two days, it was very evident from the repugnant odor
that H^S was being vented to the atmosphere as the bubbles of the air
plume were rupturing at the water surface (Figures 16 and 17). As the
lake was allowed to restratify, H^S began to increase in the bottom waters
again. When the second phase of aeration began, H S was reduced as before;
however, before it was completely dissipated, the lake became anaerobic
and H2S remained until anaerobic conditions were finally overcome at the
end of July.
During the initial aeration period, while H2S was being vented, there were
no visual adverse effects of H2$ toxicity to fish. As a matter of fact,
while H2S was venting to the atmosphere, fish were congregating in the
air plume. Releasing air at the greatest depth near the bottom may prove
to be a very economical technique of removing high concentrations of H S
in small lakes.
The effects of induced aeration on ammonia nitrogen (NH -N) were very
similar to that of the H_S (Figure 18). High bottom concentrations were
reduced during initial aeration as pH rose to 8.6, then NH_-N redeveloped
during restratification. During the second aeration phase, NH«-N in the
bottom was reduced while concentrations in the surface were increased until
the lake became well mixed. Even as anaerobic conditions developed, NH -N
was continually reduced through time as aeration proceeded. Apparently,
the NH«-N was vented to the atmosphere through the air plume similar to
H2S, since the pH remained above 8.0, and nitrite nitrogen (NCL-N) and
nitrate nitrogen (NCL-N) did not increase indicating no conversion of
NH -N to those forms.
Total Kjeldahl nitrogen reacted inversely to NH -N (Figure 19). During
stratification prior to aeration, Kjeldahl nitrogen concentrations were
higher in the surface waters than in the deeper anaerobic waters. This
phenomenon could have been a result of higher nitrogen content in the cell
structure of the dense population of algae which was released from the
cells through chemical reactions in the testing procedures, since the
samples were not filtered prior to analysis.. As the lake became mixed
during the first aeration phase, the concentration of Kjeldanl nitrogen
in both the surface and bottom waters became slightly reduced and well
mixed. During the restratification period, concentrations again increased
in both the surface and bottom waters, with the surface concentrations
becoming slightly higher as in previous normal stratification. When aeration
started a second time, mixing occurred quickly; however, the concentrations
of Kjeldahl nitrogen did not drop as sharply as in the first test, but
gradually declined with continued aeration. The initial higher mixed
condition is reasonable since there was more organic material in suspension
at the start of the second aeration test. As aeration continued, the
anaerobic environment was continually suppressed allowing lower conversion
of bottom organic nitrogen by the biota.
28
-------
AERATION
NORMAL STRAT.
RESTRATIFICATION
AERATION
RESTRAT.
TURNOVER
2.8 -
I
co 2.4
CM
X
2.0
1.6
1.2
0.8
0.4
0.0
I
STATION NO. I
STATION NO. 2
LEGEND
SURFACE
BOTTOM
20 30 10 20 30 10 20 30
MAY JUNE JULY
1969
FIGURE 15-EFFECTS ON HYDROGEN SULFIDE
29
-------
Figure 16 - Elongated Air Plume
Figure 17 - Erupting Bubbles in Air Plume
30
-------
NORMAL STRAT.
AERATION
x-RESTRATIFICATION
/ I AERATION
RESTRAT. TURNOVER
1.2
1.0
0.8
0.6
0.4
0.2
STATION NO. I
III i I I I I I I
z
i
ro
X
Z
1.2
1.0
0.8
0.6
0.4
0.2
0
LEGEND
SURFACE
BOTTOM
STATION NO. 2
I
10 20 30
JUNE
10
20 30
JULY
1969
10
20 30
AUG.
10 20 30
SEPT.
FIGURE 18 - EFFECTS ON AMMONIA NITROGEN
31
-------
NORMAL STRAT.
^-AERATION
/ ^-RESTRATIFICATION
/I ' \ AERATION
RESTRATIFICATION
o>
E
2.0
1.6
1.2
0.8
0.4
z
LJ
8 o
cc
STATION NO. I
I
<
o
_i
Ul
-5
2.0 h
1.6
1.2
0.8
0.4
0
_L
LEGEND
SURFACE
BOTTOM
STATION NO. 2
J_
10 20 30
JUNE
10 20 30
JULY
1969
10
20 30
AUG.
10
20 30
SEPT.
FIGURE 19-EFFECTS ON TOTAL KJELDAHL NITROGEN
32
-------
Aeration effects on total phosphate were very dramatic (Figure 20). The
phosphates were strongly stratified before initial aeration, then mixed
very quickly when aeration was started. When restratification was allowed,
the surface waters had slightly higher total phosphate concentrations than
the bottom. This occurrence apparently was a result of reduction of phosphates
from algal cells in the densely populated surface samples through chemical
reactions in the testing procedures. Samples were not filtered prior to
analytical tests; therefore, this phenomenon cannot be supported with test
data.
During the second aeration test, the phosphate concentration in the bottom
waters became slightly higher than in the surface, indicating that mixing
circulated the live algae throughout the water mass. After the algae
die-off, there was apparently more particulate matter held in suspension
in the surface waters than near the bottom due to the stronger current in
the surface waters created by the aerator turbulence. Evidence of this
occurrence was supported by the higher concentrations of total phosphate
in the surface waters at Station 1 as compared to Station 2 as the second
aeration progressed through the anaerobic period.
Ortho-phosphate reacted to aeration very similar to the total phosphates
(Figure 21), Ortho-phosphate concentrations in the surface and bottom
waters responded almost identically as total phosphate during the first
aeration test; however, when the lake was allowed to restratify, bottom
and surface concentrations returned to the normal pattern and did not
exhibit an inverse separation as illustrated by total phosphates. Bottom
and surface concentrations became well mixed again after 6 days of the
second aeration test; but when the algae die-off occurred, surface concen-
trations became much higher than bottom waters. This phenomenon was par-
ticularly noticeable at Station 1 near the aerator indicating the pumping
action created surface currents holding masses of organic phosphate material
in suspension near the surface.
Manganese was the only other chemical parameter measured that was significantly
affected by aeration (Figure 22). During normal stratification, there was
a high concentration of manganese near the bottom; however, as anticipated
from observations of other parameters, the bottom and surface waters quickly
mixed to an intermediate concentration when aeration started. At the beginning
of each aeration test, bottom and surface concentration mixed quickly; however,
during the second aeration test, the mixed concentration became very low
during the algae die-off. During the die-off, there was a significant in-
crease in H2S throughout the water mass which may have resulted in manganese
reacting with the sulfate ions to form manganese sulfate in solution since
free sulfate ions have been reported to remain in the water mass as H2S is
vented to the atmosphere (16). Following the algae die-off, manganese in-
creased to maximum concentration as H2S reached low levels through the
venting operation of aeration.
In addition to colorimetric tests, analyses were conducted on an array of
trace metals immediately before the first aeration and again after 3 days
of continuous aeration (Appendix Table 2). In examining Table 2, it was
33
-------
NORMAL STRAT.
£-AERATION
/ ^-RESTRATIFICATION
/I / I
AERATION
RE STRAT.
400
320
.-? 240
to
P 160
o
o 80
E
^ 0
o>
STATION NO. I
I
u
400
I 320
x
Q.
< 240
160
80
0
LEGEND
- SURFACE
— BOTTOM
STATION NO. 2
I
I I
I i
I
I
J I
20 3
MAY
10 20 30
JUNE
10 20 30
JULY
1969
10 20 30
AUG.
10
20
SEPT
FIGURE 20-EFFECTS ON TOTAL PHOSPHATE
34
-------
NORMAL STRAT.
?
AERATION
RESTRATIFICATION
STATION NO. !
10 20 30
JUNE
10 20 30
JULY
1969
20
AUG.
30
10 20 30
SEPT.
FIGURE 21 - EFFECTS ON ORTHO-PHOSPHATE
35
-------
NORMAL STRAT.
/- AERATION
7 ^RESTRATIFICATION
* r I AERATION
RESTRATIFICATION
u
y>
UJ
LEGEND
SURFACE
BOTTOM
10 20 30
JUNE
10 2O 30
JULY
1969
20 30
AUG.
10 20 30
SEPT.
FIGURE 22-EFFECTS ON MANGANESE
36
-------
found that boron, iron, manganese, and alumnium were the only metals
significantly affected by aeration. Apparently, these metals were extracted
from the bottom muds by the current created along the bottom by the uplifting
of water through the air plume. As these metals reached the surface, they
were held in suspension for a time by the surface currents near the aerator
but were not dispersed to great radial distances on the surface. (Compare
data at Stations 1 and 2.)
The total pounds of D.O. in the lake volume was computed regularly throughout
the study (Figure 23). The data presented support the earlier discussion
regarding D.O. distribution, saturation, and reduction resulting from
circulation of organic particles. Data presented illustrate there were
more pounds of D.O. in the lake during normal stratification than during
aeration periods (Figure 23); however, comparing these data with Figure 13,
it is obvious that even though there were less pounds of D.O. in the lake
during aeration, it was more equally distributed throughout the water
column during the first aeration phase. The reduction in total mass of D.O.
during the first aeration phase is a result of the oxygen circulation re-
ducing organic material from the bottom muds. Comparison of Figures 13
and 23 shows that during the beginning of the first restratification period
increased photosynthetic activity of the algae in the epilimnion increased
the total mass of D.O. but the D.O. was confined to the epilimnion.
During the later part of the first restratification period, the lake had
intensely stratified leaving a large volume of anaerobic hypolimnion and
a thinner super-saturated epilimnion resulting in an overall loss in total
pounds of D.O. At the start of the second phase of aeration, the total
mass of D.O. began to increase, but as soon as the algae die-off began,
the total mass of D.O. decreased. Circulation of the dying algae and
bottom organic deposits during the second aeration test resulted in immediate
utilization of D.O. When the compressor was turned off on July 19, the
D.O. immediately began to increase; but when the compressor was returned
to service, organic material began to circulate again and D.O. was completely
lost until the oxygen demand finally became satisfied. When final restrati-
fication was allowed, D.O. was lost for a time because the D.O. added by
the aerator had stopped and D.O. production by algae was slow since algae
concentrations were low.
Oxygen uptake tests were performed on bottom sediments on August 13, 1969,
near the end of the second aeration period. These tests were performed to
determine if, in fact, organic material carried off the bottom by currents,
created by aeration, was actually reducing the oxygen concentration in the
lake. Sediment samples were collected from the bottom at Stations 1 and 2.
These sediments were mixed with lake water of known D.O. concentration. The
mixture was put in 300 ml BOD bottles and stirred while continually measuring
the change in D.O. until it reached near zero (Table 2). The samples were
later analyzed for total suspended solids and compared with actual suspended
solids at three levels in the lake at all stations. It was noted that the
D.O. in the samples was immediately reduced to near half when sediment was
added to the surface lake water and was reduced to near zero rather quickly
as the mixed samples were continually stirred. The water samples collected
37
-------
30
28
26
24
22
S
i 20
o
o
o
o
>-
X
o
OJ O
00 £
o
-------
TABLE II
DISSOLVED OXYGEN UPTAKE TEST
Station //I
Time
(Min.)
7:58 PM
8:00 "
8:15 "
8:30 "
8:45 "
9:00 "
9:15 "
9:30 "
9:45 "
10:15 "
D.O.
mg/1
5.8a
3.2b
3.0
1.65
1.3
1.1
0.9
0.7
0.5
0.15
D.O.
X10-2
mg/l/gm TSS
64.5
60.5
33.3
26.2
22.2
18.1
14.1
10.1
3.0
Time
(Min.)
10:58 PM
11:00 "
11:15 "
11:30 "
11:45 "
12:00 M
12:15 AM
12:30 "
12:45 "
Station #2
D.O.
mg/1
6.0a
2.8b
1.85
1.35
1.05
0.8
0.55
0.45
0.40
D.O.
X10-2
mg/l/gm TSS
41.8
27.6
20.1
15.7
11.9
8.2
6.7
6.0
n
D.O. of lake water immediately before mixing with sediment
D.O. of sample immediately after mixing with sediment
NOTE: Station 1—sample contained 5048 mg/1 total suspended solids
(TSS); Station 2—sample contained 6704 mg/1 TSS; Both samples
were continually stirred during D.O. measurements.
in the lake during aeration had only 1 to 2 percent as much total suspended
solids as the test samples described in Table 2. As a result of these
lower percentages of Total Suspended Solids (TSS), oxygen uptake rates in
the lake after the algae died and aeration continued were similar to the
laboratory tests but reacted at a much slower rate.
Discussion in earlier sections pointed out that a detailed biological
monitoring program and analysis of aeration effects on various biological
parameters were part of the New Mexico Department of Game and Fish objectives,
Therefore, no data analysis or conclusions as to biological effects are
presented in this report. After normal seasonal "turnover" had occurred in
the lake and physical parameters had returned to normal for the fall months,
a profile of plankton distribution was collected at Stations 1 and 5 by the
Water Quality Control Research Program personnel (Appendix Table 3). These
data can be used as a base for analyses of data collected by the State of
New Mexico, since their sampling program did not start until seasonal
stratification had occurred and was not continued through the seasonal
"turnover" period.
39
-------
Analyses of the actual pounds of D.O. pumped versus the pounds of D.O.
actually in the lake at specific times illustrate some startling facts.
During the first phase of induced aeration, 15,900 pounds of oxygen was
pumped in a period of 144 hours with approximately 9,400 horsepower resulting
in a pumping efficiency of 1.7 pounds of D.O. per horsepower-hour of ex-
pended energy. Immediately prior to the start of the first induced aeration
phase, there was 25,300 pounds of D.O. in the lake. During the first 50
hours of compressor operation, there was an additional 5,500 pounds of oxygen
pumped into the lake. However, after 50 hours of pumping, the lake con-
tained only 21,600 pounds resulting in a net loss of 9,200 pounds. Even
though there was an actual loss in D.O., all induced aeration effects were
not negative. The hypolimnion, prior to induced aeration, was void of
D.O. below 15 feet. After 50 hours of compressor operation, there was
3,700 pounds of D.O. in the water layer below 15 feet uniformly distributed
at a concentration of 5.6 ppm to the "bottom. By the end of the first
aeration phase, 4,600 pounds of D.O. had been diffused into the hypolimnion
resulting in a uniformly distributed concentration of 6.6 mg/1 D.O. to
the bottom.
The oxygenation efficiency of the first induced aeration test was calculated
similarly to other studies (5,11). Calculations of oxygenation efficiency
for the total water mass were negative; however, calculations for the volume
below a depth of 15 feet showed that 1.2 pounds of D.O. per horsepower-hour
were added during the first 50 hours of compressor operation. By the end
of the first aeration test (144 hours), the oxygenation efficiency in this
layer had declined to 0.5 pounds of D.O. per horsepower-hour.
During the second induced aeration test, before the compressor was stopped
for repair, the lake lost all of its D.O. even though 20,300 pounds of D.O.
were pumped. After the compressor was repaired, another 31,500 pounds were
pumped and D.O. was lost again. Obviously, the organic demand was greatly
increased by circulation of organic material precipitated by the decaying
algae, resulting in an oxygen demand greater than the capacity of the aeration
system.
The intensity of thermal stratification has been used for many years by
limnologists as an arbitrary measure of the stability of a lake (17). Pre-
vious researchers have proposed the use of stability changes as a method
of calculating destratification performance (5,18,19). Stability com-
puted in work units can be described as the minimum energy required to mix
a body of water until it is completely isothermal. The ratio of stability
to total mechanical energy input expressed in percentage^, has been used as
an index of performance (destratification efficiency) for various reservoir
aeration devices.
The stability of Lake Roberts was computed regularly throughout the study
for comparison with other similar studies (Figure 24). Data illustrated
in Figures 9 and 24 show that the lake became thermally destratified in a
very short period of time, indicating a relatively high destratification
efficiency. However, high destratification efficiency should not be inter-
preted as indicating a high rate of oxygenation efficiency as illustrated
by previous discussion of problems encountered in incorporating D.O. through-
out the water mass.
40
-------
-PHASE-I AERATION
2.0 -
1.6
1.2
I 0.8
-------
Comparison of the destratification efficiency with data reported by
Bernhart (5) showed that the efficiency of the system tested in Lake
Roberts during initial aeration was very near that of Boltz Lake which
has similar physical characteristics (Table 3). However, computations show
there is a gradual decrease in destratification efficiency as induced
aeration is continued. This decrease indicates that when stratification
is initially overcome and the lake becomes isothermal, power should be
reduced accordingly to maintain a destratified condition at a minimal input
of energy. Continued induced aeration at the initial energy input rates
results in a progressive waste of energy reducing destratification
efficiency.
At the end of the first restratification test, the lake had not returned
to its former stable condition but had reached approximately 90 percent
of the stability at the beginning of the first aeration test. The second
aeration test was conducted at an induced aeration rate of 54 cfm of air
input compared to 100 cfm in the first test. Comparing the first 74
hours of each test shows that the destratification efficiency of the
second test was almost twice that of the first test, again indicating an
excess of energy used in the first test.
42
-------
TABLE III
COMPARISON OF VARIOUS DESTRATIFICATION EFFICIENCIES
(5)
-p-
oo
Lake
(1)
Lake Roberts
70 acres
980 acre-ft.
Max. depth, 30ft
Boltz Lake
96 acres
2400 acre-ft.
Max. depth, 60ft
Before
Aeration
Kw-hr
(2)
2.02*
2.02b
2.02'
. 1.78d
44. 4e
•
Stability
After Stability
Destratif ication Decrease
Kw-hr Kw-hr
(3) (4)
0.47* 1.55*
0.38 1.64
0.14° 1.88'
0.49d 1.29d
11. 8e 32. 6-13=19. 6f
Approximate
Total Energy
Used
Kw-hr
(5)
1120*
3630
6980'
1930
14300s
Energy Used
Per Unit
Lake Volume
Kw-hr/acre-f t .
(6)
3.7b
7.1'
2.0d
5.9e
Destratif ication
Efficiency
(Column 44-5)
Percent
(7)
0.14*
0.04b
0.03'
0.07d
0.14e
Lake Wohlford
130 acres
2500 acre-ft.
Max. Depth, 50ft.
14.7s
1.1*
13.6*
2910g
1.2*
0.47
g
Wa,b,nback Reservoir
530 acres
33740 acre-ft.
Max, depth, 141ft.
400*
104,800
,S
3.1*
0.38*
Aeration Phase No. 1, after 23 hours at 100 cfm
Aeration Phase No. 1, after 74 hours at 100 cfm
,Aeration Phase No. 1, after 144 hours and maximum accumulation of free oxygen at 100 cfm
Aeration Phase No. 2, after 74 hours aeration at 54 cfm
..Using mechanical pump to lift bottom water to surface
Stability decreased because of natural particle circulation
Blowing in air on the bottom of the lake and discharging aerated water below hypolimnion
-------
SECTION VII
ACKNOWLEDGMENTS
Sincere appreciation is expressed to the State of New Mexico and the
Department of Game and Fish for their cooperation and participation in
conducting this experiment on one of their trout-fishery lakes. Public
relations and manpower effort provided by the research unit of the New
Mexico Game and Fish Department allowed this research, which significantly
added to the technology of reservoir destratification through induced
aeration.
Special appreciation is expressed to Officers J. E. Syling, Dean Smith,
and Robert Trippeer of the New Mexico State Police, whose diving service
made possible safe installation of the air distribution system on the
bottom of Lake Roberts.
Appreciation is expressed to the Kennacott Mining Corporation of Bayard,
New Mexico, for the loan of an air compressor and air hose for the duration
of the project. Without this valuable contribution, the study would have
been difficult to complete.
45
-------
SECTION VIII
REFERENCES
1. Laurie, A. H., "The Application of the 'Bubble-Gun' Low-Life Pump, A
Remedy for Stratification Problems," Water and Waste Treatment, Vol. 8,
(1961).
2. Fast, A. W., "Artificial Destratification of El Capitan Reservoir by
Aeration," California Department of Fish and Game, Fish Bulletin 141,
(1968).
3. Speece, R. E., "The Use of Pure Oxygen in River and Impoundment Aeration,"
Presented at the 24th Purdue Industrial Waste Conference, (May 8, 1969).
4. Ford, M. E., Jr., "Air Injection for Control of Reservoir Limnology,"
Journal AWWA, 55:3, (March 1963).
5. Bernhart, H., "Aeration of Wahnback Reservoir Without Changing the
Temperature Profile," Journal AWWA, 55:8, (August 1967).
6. Hooper, F. F., Ball, R. C., and Tanmer, H. A., "An Experiment in the
Artificial Circulation of a Small Michigan Lake," Trans. American
Fish Society, 82, (1952).
7. VanRay, L. C., "Evaluation of Artificial Aeration in Stockade Lake,"
S. D. Department of Game, Fish, and Parks, D.-J. Proj. No. F-15-R-1,
Job No. 1, Compl. Rept. (1966).
8. Austin, G, H., Grady, D, A., and Swain, D, G., "Report on Multilevel
Outlet Works at Four Existing Reservoirs," Office of Chief Engineer,
Bureau of REC, USDI, Denver, Colorado, (1968).
9. Symons, J. M., Irwin, W. H., Robinson, E. L., and Robeck, G. C.,
"Impoundment Destratification for Water Quality Control:Mechanical
Pumping and Diffused Air," Presented at the 87th Annual Conference of
AWWA, Atlantic City, New Jersey, (June 4-9, 1967).
10. Leach, L. E., Duffer, W. R., and Harlin, C. C., Jr., "Pilot Study of
Dynamics of Reservoir Destratification," Robert S, Kerr Water Research
Center, Federal Water Quality Administration, USDI, Ada, Oklahoma,
(1967).
11. Wood, M. L. and Leach, L. E., "Current Research on Reservoir Destratification,"
Proceedings of the 8th Annual Environmental and Water Resources Engineering
Conference, Technical Report No. 20, (June 5-6, 1969).
12. Leach, L. E., "Eufaula Reservoir Aeration Research—1968," Proceedings
of the Oklahoma Academy of Science, Vol. XLIX, pp. 175-181, (1968).
47
-------
13. Federal Water Pollution Control Administration Methods for Chemical
Analysis of Water and Waste, (November 1969).
14. Robinson, E. L., Irwin, W. H., Symons, J. M., "Influence of Artificial
Destratification on Plankton Populations in Impoundments," Water Quality
Behavior in Reservoirs, A Compilation of Published Research Papers,
Paper No. 13, USDHEW, Bureau of Water Hygiene, (1969).
15. Karlgren, L., Luftningstudier i Trasksjon," Vattenhygien, 3:67, (1963).
16. Haney, P. D., "Theoretical Principals of Aeration," Journal AWWA,
46:4, (April 1954).
17. Ruttner, F., Fundamentals of Limnology, 3rd Edition, University of
Toronto Press, pp. 30-34, (1966).
18. Symons, J. M. and Robeck, G. G., "Calculation Technique for Destratification
Efficiency," Water Quality Behavior in Reservoirs, A Compilation of
Published Research Papers, Paper No. 10, USDHEW, Bureau of Water
Hygiene, (1969).
19. Cleary, E. J., "The Reaeration of Rivers," Industrial Water Engineering,
pp. 16-21, (June 1966).
48
-------
APPENDIX
-------
TABLE I
AERATION CHANGES IN CHEMICAL PARAMETERS
Depth
Sta,
1
1
1
2
2
2
3
3
3
1
1
1
2
2
2
3
3
3
1
1
1
2
2
2
3
3
i
1
1
2
2
2
3
3
. Date
5-22-69
5-22-69
5-22-69
5-22-69
5-22-69
5-22-69
5-22-69
5-22-69
5-22-69
6-15-69
6-15-69
6-15-69
6-15-69
6-15-69
6-15-69
6-15-69
6-15-69
6-15-69
6-18-69
6-18-69
6-18-69
6-18-69
6-18-69
6-18-69
6-18-69
6-18-69
6-22-69
6-22-69
6-22-69
6-22-69
6-22-69
6-22-69
6-22-69
6-22-69
Feet
0
15
29
0
10
23
0
5
10
0
15
29
0
10
24
0
5
10
0
15
29
0
12
24
0
10
0
15
29
0
12
23
0
10
PH
8.
8.
7.
8.
8.
7.
8.
8.
8.
9.
8.
7.
9.
9.
7.
9.
8.
8.
9.
8.
7.
9.
8.
7.
—
—
8.
8.
8.
8.
8.
8.
8.
8.
4
4
5
5
5
6
4
5
3
05
7
7
1
0
4
3
8
0
0
3
7
2
6
6
-
-
65
65
65
65
65
65
81
65
Cond.
Cl
umho / cm mg / 1
359
359
380
359
360
370
360
360
360
240
305
425
250
265
410
245
290
320
300
325
365
265
290
360
305
315
310
305
315
305
305
310
3.0
3.0
3.0
3.2
2.7
3.0
3.0
3.0
3.2
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
4.0
3.0
4.0
4.0
4.0
3.0
3.0
3.0
4.0
3.0
3.0
4.0
4.0
S04
mg/1
27.5
27.5
23.5
27.0
27.0
25.5
27.0
28.0
26.5
21.0
18.0
8.0
8.0
19.0
12.0
18.0
14.0
13.0
27.0
27.0
27.0
28.0
26.0
26.0
29.0
27.0
26.0
28.0
31.0
28.0
28.0
28.0
27.0
27.0
Total TD
Solids Solids T-P04
mg/1
245
249
280
245
246
270
244
248
239
mg/1
240
244
274
241
241
264
239
243
233
mg/1
0.031
0.024
0.260
0.038
0.029
0.163
0.032
0.037
0.042
0.140
0.060
0.407
0.068
0.046
0.367
0.056
0.025
0.100
0.086
0.086
0.093
0.130
0.073
0.066
0.071
0.097
0.057
0.067
0,065
0.105
0.047
0.036
0.056
0.051
Ortho
P04
mg/1
0.063
0.051
0.396
0.003
0.021
0.342
0.012
0.015
0.063
0.007
0.006
0.022
0.012
0.011
0.019
0.004
0.011
0.008
0.008
0.017
0.006
0.008
0.020
0.006
0.008
49
-------
TABLE I—Continued
NH3-N
ing/1
0.17
0.15
1.11
.09
.09
1.20
0.08
0.10
0.24
0.16
0.18
0.16
0.18
0.13
0.25
0.07
0.07
0.17
0.15
0.42
0.14
0.18
0.14
0.13
0. 08
T-Nitrogen
rag/1
M__
1.8
0.5
1.3
0.9
0.8
1.2
0.8
0.7
0.4
0.7
0.8
0.8
0.9
0.7
0.7
0.8
0.7
0.7
0.7
0.9
0.8
0.8
0.8
0.5
0.6
N02-N
rag/1
«»«
<.03
<.03
<.03
<.03
<.03
<.03
<-03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
N03-N
rag/1
_..
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
H2S
mg/1
0
0
0.51
0
0
0
0
0
0
0
0.05
2.60
0.00
0.10
2.65
0.15
0.10
0.00
0.35
1.80
0
0.1
1.75
0.02
0.02
0
0
0
0
0
0
0
0
Fe
mg/1
— —
.26
.23
.19
.23
.22
.16
.18
.22
.24
.20
.31
.22
.21
.21
.23
.18
.23
Mn
mg/1
»«••»
.14
.22
2.13
.15
.16
2.10
.15
.18
.50
.67
.67
.68
.48
.62
.76
.52
.50
Cn
mg/1
<.02
<.02
<.02
<.02
<.02
<.02
<.02
<.02
Ca
mg/1
56.0
56.0
58.5
55.5
56.0
56.5
53.5
55.5
56.5
Mg
mg/1
9.9
9.5
9.7
9.6
9.7
9.7
9.5
9.7
9.5
Hack Test
50
-------
TABLE I—Continued
Sta.
1
1
1
2
2
2
3
3
1
1
1
2
2
2
3
3
1
1
1
2
2
2
3
3
3
1
1
1
2
2
2
3
3
1
1
1
2
2
2
3
3
Date
6-30-69
6-30-69
6-30-69
6-30-69
6-30-69
6-30-69
6-30-69
6-30-69
7-9-69
7-9-69
7-9-69
7-9-69
7-9-69
7-9-69
7-9-69
7-9-69
7-16-69
7-16-69
7-16-69
7-16-69
7-16-69
7-16-69
7-16-69
7-16-69
7-16-69
8-3-69
8-3-69
8-3-69
8-3-69
8-3-69
8-3-69
8-3-69
8-3-69
10-15-69
10-15-69
10-15-69
10-15-69
10-15-69
10-15-69
10-15-69
10-15-69
Depth
Feet
0
15
29
0
12
23
0
10
0
15
29
0
12
24
0
10
0
15
29
0
20
23
0
5
10
0
15
29
0
12
24
0
10
0
10
29
0
12
24
0
10
pH
9.25
8.7
8.0
9.3
8.8
8.5
9.28
8.85
9.3
8.0
7.6
9.4
8.4
8.1
9.4
8.7
7.95
7.80
7.75
7.90
7.95
7.90
7.9
7.85
8.1
8.1
8.1
8.1
7.9
7.85
8.1
8.1
7.7
8.2
7.9
7.7
7.8
7.85
7.7
7.7
Cond.
uraho/cm
280
300
320
280
305
320
300
320
295
320
350
295
320
345
300
320
345
345
345
345
350
355
340
340
340
335
330
320
325
325
325
325
280
280
300
290
300
290
290
300
S04
mg/1
33
29
27
39
28
28
30
30
30
27
26
30
27
23
29
26
25
25
26
27
25
26
25
25
24
23
25
25
25
24
25
24
24
Total
TD
Solids Solids T-P04
mg/1
200
200
199
196
310
255
268
265
267
306
299
250
mg/1
192
189
191
187
300
241
247
247
254
285
280
229
mg/1
0.260
0.031
0.241
0.275
0.072
0.125
0.037
0.042
0.093
0.110
0.156
0.131
0.109
0.209
0.089
0.191
0.223
0.195
0.195
0.173
0.182
0.226
0.207
0.185
0.182
0.325
0.120
0.130
0.180
0.130
0.135
0.160
0.120
0.143
0.165
0.226
0.145
0.160
0.167
0.176
0.199
Ortho
P04
rag/1
0.008
0.030
0.203
0.007
0.036
0.079
0.007
0.042
0.004
0.023
0.093
0.006
0.065
0.153
0.009
0.100
0.055
0.055
0.055
0.043
0.053
0.074
0.038
0.043
0.045
0.250
0.060
0.056
0.100
0.055
0.059
0.072
0.057
0.080
0.120
0.140
0.075
0.076
0.086
0.084
0.082
NH3-N
mg/1
0.12
0.18
0.48
0.14
0.21
0.41
0.11
0.23
0.14
0.42
0.96
.14
.42
.96
0.15
0.50
0.46
0.43
0.53
0.43
0.44
0.50
.43
.48
0.34
0.32
0.38
0.30
0.33
0.31
0.30
0.28
0.12
0.09
0.11
0.09
0.09
0.07
0.18
0.09
51
-------
TABLE I—Continued
Total Nitrogen
mg/1
1.8
0.7
1.4
1.9
1.4
1.4
1.1
0.7
1.02
0.92
1.27
1.22
1.01
1.45
1.05
1.10
1.34
1.30
1.28
1.40
1.30
1.40
1.38
1.38
1.34
0.90
0.80
0.90
0.90
0.90
0.90
0.80
1.00
0.6
0.7
0.7
0.6
0.6
0.6
0.6
0.7
N02-N
mg/1
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
N03-N
mg/1
*03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
<.03
H2S
mg/1
0
0
.3
0
0
0.09
0
0
0
0
0.45
0
0
1.2
1.10
1.35
1.45
1.15
1.45
1.95
1.05
1.25
0
0
0
0
0
0.2
Fe
mg/1
.51
.36
.38
.66
.34
.33
.41
.43
.13
.13
.18
.13
.18
.19
0.14
0.21
0.13
0.13
0.135
.15
.15
.12
.15
.15
.15
.06
.06
.04
.03
.04
.13
.08
.08
0.10
0.08
0.20
0.08
0.15
0.05
0.08
0.10
Mn Cn
mg/1 mg/1
.39 <.02
.50 <.02
1.15 <.02
.35 <.02
.51 <.02
.68 <.02
.31 <.02
.49 <.02
.27
.72
1.15
.28
.52
1.03
0.30
0.69
0.09
0.15
0.11
.17
.16
.11
.08
.11
.09
.70
.70
.75
.70
.64
.70
.64
.67
0.46
0.46
0.46
0.48
0.47
0.48
0.46
0.47
COD BOD
mg/1 mg/1
*
*
*
*
*
*
*
*
£
27
24
29
5.1
6.6
6.4
7.1
6.3
4.3
12.0
6.5
*
Dilutions too low, less than 4 mg/1 BOD at all Stations
52
-------
TABLE II
AERATION EFFECTS ON TRACE METALS
Sta.
1
1
1
2
2
2
3
3
3
1
1
1
2
2
2
3
3
Date
5-22-69
5-22-69
5-22-69
5-22-69
5-22-69
5-22-69
5-22-69
5-22-69
5-22-69
6-18-69
6-18-69
6-18-69
6-18-69
6-18-69
6-18-69
6-18-69
6-18-69
Depth
Ft.
0
15
29
0
10
23
0
5
10
0
15
29
0
10
24
0
10
Zn
ug/1
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
Cd
ug/1
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
B
ug/1
<20
34
46
<20
20
64
20
40
54
180
100
120
120
130
90
120
85
Fe
ug/1
10
40
20
14
22
20
14
16
32
130
110
110
80
100
120
90
110
Mo
ug/1
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
Sn
ug/1
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
Mn
ug/1
60
160
1040
84
108
620
100
100
190
620
560
580
460
420
480
420
420
CU
ug/1
10
10
10
<10
10
20
26
15
<10
<10
<10
<10
<10
<10
<10
<10
Ag Ni
ug/1 ug/1
<10 <20
<10 <20
<10 <20
<10 <20
<10 <20
<10 <20
<10 <20
<10 <20
<10 <20
<10 <20
<10 <20
<10 <20
<10 <20
<10 <20
<10 <20
<10 <20
<10 <20
Al
ug/1
<10
60
32
<10
32
36
17
<10
76
170
145
145
80
100
160
90
130
Pb
ug/1
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
<60
Cr
ug/1
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
Ba Sr
ug/1 ug/1
<10 34
<10 80
22 72
<10 38
<10 48
22 104
<10 38
<10 44
22 84
<10 85
<10 85
<10 80
<10 60
<10 60
<10 70
<10 70
<10 60
-------
TABLE III
PLANKTON ANALYSIS
Organisms Collected
October 15, 1969
Number of Kinds
Number /Milliliter
Chlorophyta-green
Ankistrodesmus sp.
Bascicladia sp.
Chlamydomonas sp.
Gonatozygon sp.
Oocystis sp.
Planktospheria sp.
Po lyb lephar ides sp.
Polytomella sp.
Spirogyra sp.
Rhizoclonium sp.
Chrysophyta-yellow-brown
Amphora sp.
Epithemia sp.
Fragilaria sp.
Mallomonas sp.
Navicula sp.
Nitzschia sp.
Synedra sp.
Tribonema sp.
Uroglenopsis sp.
Melosira sp.
Cyanophyta-blue-green
Oscillatoria sp.
Euglenophyta-euglenoid
Euglena sp.
Lepocinclis sp.
Rhabdomonas sp.
Trachelomonas sp.
Pyrrophyta-dinoflagellates
Ceratium sp.
Protozoa-single-celled animal
Strombidium sp.
Rota tor ia-wheeled-animacules
Asplanchna sp.
Trichocera sp.
Sta.#l Sta.#l Sta.//l
Surface 15' 30'
18 18 21
1646 1876 1845
28 28 28
28
28 57 57
28
57 28 28
28 28
57 228 114
28 114 114
199 142 114
57 57
28
28
85 28 85
57 28 28
28
o o
£O
256 199 256
28 57
28 28
28 — 57
28
28 57 85
28 -- 28
627 684 598
28 28 28
57
28
Sta.#5
Surface
16
1820
57
85
57
57
114
114
85
85
85
28
114
57
85
57
712
28
Sta.#5
Bottom
20
1816
28
57
28
28
142
199
285
28
28
28
57
28
199
28
28
28
28
57
484
28
NOTE: Two strip count at 10x10x2 power with conversion factor equaling
number individuals counted times 28.5=No./Ml.
54
-------
TABLE III
PLANKTON ANALYSIS
Organisms Collected
October 15, 1969
Number of Kinds
Number /Millillter
Chlorophyta-green
Ankistrodesmus sp.
Bascicladia sp.
Chlamydomonas sp.
Gonatozygon sp.
Oocystis sp.
Planktospheria sp.
Po lyb lephar id es sp.
Pqlytomella sp.
Spirogyra sp.
Rhizoclonium sp.
Chrysophyta-yellow-brown
Amphora sp.
Epithemia sp.
Fragilaria sp.
Mallotnonas sp .
Navicula sp.
Nitzschia sp.
Synedra sp.
Tribonema sp.
Uroglenopsis sp.
Melosira sp.
Cyanophyta-blue-green
Oscillatoria sp.
Euglenophyta-euglenoid
Euglena sp.
Lepocinclis sp.
Rhabdomonas sp.
Trachelomonas sp.
Pyrrophyta-dinof lagellates
Ceratium sp.
Protozoa-single-celled animal
Strombidium sp.
Rotatoria-wheeled-animacules
Asplanchna sp.
Trichocera sp.
Sta.//l Sta.//l Sta.#l
Surface 15' 30'
18 18 21
1646 1876 1845
28 28 28
28
28 57 57
28
57 28 28
28 28
57 228 114
28 114 114
199 142 114
57 57
28
28
85 28 85
57 28 28
28
28
256 199 256
28 57
28 28
28 — 57
28
28 57 85
28 -- 28
627 684 598
28 28 28
57
28
Sta.#5
Surface
16
1820
57
85
57
57
114
114
85
85
85
28
114
57
85
57
712
28
Sta.#5
Bottom
20
1816
28
57
28
28
142
199
285
28
28
28
57
28
199
28
28
28
28
57
484
28
NOTE: Two strip count at 10x10x2 power with conversion factor equaling
number individuals counted times 28.5=No./Ml.
54
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1
5
Accession Number
2
Organization
Environmental
Subject Field & Group
05G
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Protection Agency, Water Quality Office
Robert S. Kerr Water Research Center
Ada, Oklahoma
Title
INDUCED AERATION OF SMALL MOUNTAIN LAKES,
1Q Authors)
Harlin, Curtis C., Jr.
16
21
Project Designation
16080 11/70
Note
22
Citation
23
Descriptors (Starred First)
"*Water quality control, *Aeration, Impoundments, Stratification, Water circulation,
Oxygenation, Economic efficiency
25
Identifiers (Starred First)
*Destratification, Nutrient suppression
27
Abstract
Summer stratification in small mountain trout-fishery lakes restricts trout habitat to
the thin layer of surface water. As atmospheric temperatures increase during later
summer months, the epilimnion waters reach temperatures intolerable for trout. A
technique of managing trout-fishery lakes, through introduction of compressed air,
was studied at Lake Roberts in southern New Mexico during the summer of 1969. Research
was conducted to determine the feasibility of induced aeration to control nutrient
stratification and dissipation of high-bottom concentrations of hydrogen sulfide.
The oxygenation efficiency of the induced aeration system was evaluated, and futher
research required for optimum development of the systems as management tools for
trout-fishery lakes is discussed.
institution Robert S. Kerr Water Research uenter,
Environmental Protection Agency,
Abstractor,
Lowell E. Leach
WR:<02 (REV. JULY 1969)
WRSIC
SEND TO: WATER RESOURCES SCIENTii-,^ INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 2024O
« CPO: 1968-359-339
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