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Group Title: Mimeo report - UF Central Florida Experiment Station ; CFES-68-6
Title: Water quality studies, Zellwood drainage and water control district
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Title: Water quality studies, Zellwood drainage and water control district
Series Title: Mimeo report - UF Central Florida Experiment Station ; CFES-68-6
Physical Description: Book
Language: English
Creator: Forbes, Richard Brainard
Publisher: Central Florida Experiment Station, University of Florida
Publication Date: 1968
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Bibliographic ID: UF00075823
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 123233207

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HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida












CENTRAL FLORIDA EXPERIMENT STATION
Sanford, Florida



Mimeo Report CFES 68-6 December 16, 1968



WATER QUALITY STUDIES, ZELLWOOD DRAINAGE
AND WATER CONTROL DISTRICT



R. B. Forbes, Associate Soils Chemist



Lake Apopka, a 31,000 acre body of fresh water in Central Florida,
bordered by both Orange and Lake Counties, is in the heart of a rich
agricultural district. The city of Winter Garden and the towns of Oakland,
Monteverde, and Ferndale adjoin the lake. Along the marshy northern shore
of the lake the mucklands have been drained and put into intensive vege-
table farming operations. The Zellwood Drainage and Water Control District
(7) includes 9000 acres. In addition, approximately 9000 acres of muckland
farms lie west of the drainage district near Lake Jem and Astatula. Much
of the remainder of the lake shore is bordered by citrus groves or resi-
dential property on the surrounding highlands. Lake Apopka is at the head
of a chain of lakes which includes Beauclair, Dora, Eustis and Griffin
which drains into the Oklawaha River.

About 10 miles of levee separates the lake from the farming areas
which are about 3 feet lower than the average lake level. Drainage is
accomplished by a system of mole drains and field ditches which discharge
excess water into a system of canals. From the Zellwood Drainage District,
the water is pumped over the levee directly into Lake Apopka. The farms in
the Lake Jem-Astatula area pump their drainage into the Apopka-Beauclair
canal, the lake outlet. In dry periods, lake water or seepage water in
the canals is used for irrigation. Little pumping occurs during dry
seasons except when canal levels occasionally become too high through
seepage and ground water accumulations. Then it becomes necessary to
pump for short periods to lower the water table.


SHUME LIBRARY


JAN 24 1969
100 copies 2

S.F.A.S. U.. of Florida
*T'---F-lo









-2-


In recent years much public concern has arisen over the apparent
"pollution" (according to Webster, to pollute means to render unclean or
impure) of Lake Apopka over the last 20 years. The condition of the lake
was described in detail in a joint study by the Florida State Board of
Health and Game Fresh Water Fish Commission (5) published in 1965. The
local press has also documented "Lake Apopka's Lingering Death" (6), and
much unfavorable publicity has been given.

Briefly, even to the casual observer, the lake appears "dirty' or
"polluted". A heavy algae bloom occurs and loose deposits on the lake
bottom become stirred up during windy weather giving muddy water and poor
reproduction of game fish and fish foods. The fishing has declined to
the point that fishing camps are going out of business in what was once
a productive fishing area for bass, perch and bream. Many catfish are
still in evidence and the population of rough fish has been high (2, 5).
Three large scale rotenone treatments over a period of years killed an
estimated 20 million pounds of rough fish which decayed in the lake.
Further enrichment occurred from decay of plant materials resulting from
hyacinth control sprays and from submersed acquatic plants uprooted by a
hurricane. The equilibrium between this type of vegetation (eelgrass,
pondweed, etc.) (2, 5) and the algae was upset, giving a vast increase
in algae, stimulated by the uncalculable tons of plant nutrients added
to the water by decay of these dead fish and plant materials.

Among the conclusions cited in the State Board of Health report (5),
the main problems or sources of undesirable conditions were excessive
nutrients and the semi-suspended bottom debris or muds composed of plant
detritus and algal residues. The report listed phosphates and nitrates
as being the primary ingredients of the excessive nutrients. The sources
from which these nutrients originated were reported (2, 5) as follows:

1. Decayed fish resulting from the rotenone treatment. 2. Decayed
hyacinths and other aquatic plants. 3. Wastes from citrus processing
plants. 4. Effluent from sewage disposal system. 5. Drainage water
from the muck farms.

The authors point out that "the present condition of the lake is the
result of a host of factors which tend to further modify and accelerate
events which would have taken place regardless of man's activities. Lake
Apopka is one of Florida's older lakes and, as such, is in the terminal
stages of its development leading toward formation of a marsh."

This present study by the Experiment Station was undertaken on re-
quest of the Orange County Agricultural Agent, Henry F. Swanson, and the
growers in the Zellwood area to gain more information about the alleged
"pollution" of the lake by farming operations on the muck.









-3-


Procedures

After consultation with the engineer and directors in charge of the
drainage district, a system of sampling was set up to collect representative
water samples from various parts of the district. During the first few
sampling periods more sites were included until the 10 locations described
in Table 1 became standard.

For comparison with a source outside the district, samples have been
taken since June 1967 from the St. John's River. Starting in May 1967
(to coincide with the sweet corn dusting season) the samples have been
checked for DDT and parathion by the Chemical Division of the Florida
Department of Agriculture.

Analyses run at the Central Florida Station include pH, soluble salts,
nitrates (by diphenylamine) and total solids according to A.O.A.C. methods (1).
Portions of each sample were sent to the Florida Agricultural Extension
Service Soil Testing Laboratory at Gainesville for determination of
dissolved phosphorus, potassium, calcium, and magnesium.


Table 1.- Water Sampling Stations, Zellwood Drainage and Water Control District.

Sample
Station No. Location

1 Rim ditch at junction with canal from Zellwin sand
land farm.

2 At bridge opposite Potter Property on Interceptor
Canal leading to Pumping Plant No.. 1.

3 Canal No. 2, opposite CFES farm, 1.3 mi. E of
Pumping Plant No. 4.

4 Canal to Big Pumphouse (Pump No. 2).

5 Canal to Pump No. 3 (Hooper farms).

6 At discharge weir from Holtz Lake, Plymouth.

7 Apopka-Beauclair Canal, north of lock.

8 Lake Apopka, off Fisherman's Paradise docks.

9 Lake Apopka, 100 yards offshore from Pumping Plant
No. 2.

10 Lake Apopka, mid-lake approximately 2 mi. S.W. of
Pumping Plant No. 2.
| i- ,i-- ii i- .,










Results and Discussion


At the present stage of this study, 36 sets of samples have been
analyzed over the past 2 years.

Tables 2 and 3 show seasonal averages for total solids, soluble salts,
and several plant nutrients, from samples taken during warm wet periods
and cool, dry seasons, respectively. Two seasonal trends became apparent
in the analyses: 1. During dry periods, the water in the canals was in
the same range of concentration for nutrients and total solids as that
in the lake. A nutrient build up in the lake took place over the dry
months. 2. During the wet season, the concentrations in the lake tended
to go down with the dilution effect of rain. During this time, the water
being pumped from the canals into the lake was generally higher in
nutrients and salts than during the dry, cool weather. This was thought
to be due to heavy rains which leach nutrients through the profile and
eventually into the canals to be pumped over the levee into the lake.
Even with this fresh supply of nutrients being added, the lake concentration
went down with the dilution from the rains.

In the summer of 1968, some 45 inches of rain fell during the period
from mid-May to mid-September. As a result, the condition of the lake
appeared better by September. Water clarity was visibly improved and the
levels of solids, salts, and nutrients were lower than those found during
extended dry weather. Tables 4 and 5 show analyses typical of both dry
and wet periods. Actually, at some dry weather sampling dates, levels
of total solids in the lake were higher than those shown in these examples.
the highest recorded in the lake was 588 ppm total solids on February 29,
1968.








-5-

Table 2.- Water Analyses, Apopka-Zellwood area; average values for warm,
wet season (April October) 1967.

Sample Station Total Soluble
Number Solids Salts P K Ca Mg
ppm


1

2

3

4

5

Average for canals

6

7

8 (Lake)

9 (Lake)

10 (Lake)

Average for Lake


St. Johns River
@ S.R. 415


181*

352

455

413

396

359

205

298

337

331

321

330


201

348

362

402

381

339

280

299

258

266

261

262


898


0.52

0.35

1.00

0.57

0.44

0.58

0.04

0.31

0.13

0.09

0.09

0.10


5.6

7.6

11.4

8.7

8.3

8.3

3.2

7.7

7.1

6.8

6.8

6.9


13.0

30.9

31.5

35.7

29.4

28.1

23.9

22.0

16.1

16.7

15.4

16.1


2.6

6.5

7.4

8.3

8.9

6.7

5.2

6.0

5.7

6.0

6.0

5.9


0.22 10.0 35.3 8.1


* Mud from ditching operations gave one abnormally high (3545 ppm) value
9-27-67 which was omitted in this average.








- 6 -


Table 3.- Water analyses, Apopka-Zellwood area;
season (November 67 April 68).


average values during cool, dry


Sample Station Total Soluble
Number Solids Salts P K Ca Mg
ppm


1

2

3

4

5

Average for canals

6

7

8 (Lake)

9 (Lake)

10 (Lake)

Average for lake


St. Johns River
@ S.R. 415


178

278

325

334

401

303

188

306

362

335

329

342


1335


222

310

322

336

385

315

238

315

294

286

277

286


1307


0.17

0.04

0.09

0.13

0.04

0.09

0.04

0.22

Tracel/

Trace

Trace

Tr.


0.03


3.4

5.2

6.5

7.3

7.0

5.9

2.7

9.4

7.5

7.3

7.1

7.3


13.3


20.8

35.8

36.4

34.2

38.4

33.1

28.4

31.9

26.5

24.5

24.6

25.2


3.9

6.2

7.4

8.3

9.4

7.0

5.6

7.4

7.0

7.4

7.2

7.2


60.7 12.8


1/Less than 0.04 ppm P.








-7-


Table 4.- Water analyses, 1-30-68, typical of dry season samples.

Sample Station Total Soluble
Number pH Solids Salts P K Ca Mg
ppm


(Lake)

(Lake)

(Lake)


7.3

7.4

7.6

7.6

7.8

7.5

7.7

8.6

7.6

8.6


95

177

248

311

436

198

344

312

349

331


266

252

280

280

420

266

336

336

322

280


0.35

0.04
0.09


0.13

0.04

0.04

0.61

Trace

0.04

Trace


4.0

5.5

8.1

8.1

7.1

4.5

16.2

8.6

7.6

8.6


27.4

37.0

37.0

33.8

46.4

30.6

40.2

30.6

37.0

30.6


4.6

6.0

7.5

7.5

8.3

5.3

8.3

6.8

10.0

9.2


St. Johns River
@ S.R. 415 8.3


0.04 14.0 39.4 13.9


1160 1190








- 8 -


Table 5.- Water analyses, 9-12-68, typical of rainy season samples /.

Sample Station Total Soluble
Number pH Solids Salts P K Ca Mg
ppm

1 6.8 108 168 0.087 5.0 6.0 2.2

2 7.4 586 525 0.061 7.6 53.0 13.1

3 7.6 597 595 0.026 6.5 53.0 14.9

4 7.4 551 525 0.157 8.1 40.0 11.2

5 7.7 715 630 0.148 10.3 50.0 14.9

6 no sample -- -- -- -- -- --

7 7.6 315 322 0.026 5.5 18.0 8.5

8 (Lake) 8.6 278 266 0.004 5.0 15.0 7.7

9 (Lake) 8.8 304 308 0.013 5.0 15.0 8.5

10 (Lake) 9.0 266 252 0.004 4.5 12.0 4.0


St. Johns River
@ S.R. 415 7.7 440 455 0.013 3.0 12.0 2.7


/ During the proceeding 4 months, 45 inches of rainfall was recorded
at the Zellwood farm of the Central Florida Experiment Station.

The term total solids is used as a yardstick of pollution in these
analyses and expresses the total load carried by water, of both suspended
and dissolved materials.

Much of the muckland is underlain with marl and the soil is of a
high calcium content. As a result, the pH values found in the canal
waters were usually in the neutral to slightly alkaline range. Many
of the lake samples were of much higher pH, in the 8.5 to 9 range.
This has been attributed to the effects of high algae content (5).

Since nitrate nitrogen was very low in most of the lake samples
these data are not presented. Presumably nitrate nitrogen is used up
rapidly by the algae or plankton growth. However, in occasional canal
samples during the warm wet season, nitrates were found in quantities of
2 to 5 ppm.








-9-
Phosphorus levels were very low when compared to soil levels.
However, Walker and Wadleigh (9) state that algae grow vigorously in
water of only 0.1 ppm P content. To prevent algal growth they indicate
that P levels below 0.02 ppm may be necessary. Many of the water
samples from the canals were higher than these levels. Wadleigh (8)
indicated that phosphorus is the key factor for algal growth in most
waters.

No parathion was found in any of the samples analyzed. No DDT
was found in the lake water, but it was detected in a very few of the
samples from the canals, generally those adjacent to corn fields. The
two highest concentrations found were 0.25 and 0.18 ppm. From July
11, 1967, when one sample contained 0.05 ppm DDT, all samples were
negative until May 28, 1968 when 0.01 ppm was found in two of the
samples. These results were discussed by Forbes (3, 4) in Experiment
Station Annual Reports for 1967 and 1968. Huffstutler, et al, (5)
indicated the pesticides have not been a major factor in the decline
of the lake. Their results do chow that some DDT was reaching the lake
since measurable quantities were picked up in fish and algae from the
lake. They indicated that algae and lake bottom muds were effective
for absorbing DDT and nullifying its toxicity.

From the foregoing it may be seen that even though pesticide
contributions were very small, the nutrient content of the canal water
being pumped into the lake cannot be overlooked. For example, say there
are 7 pumps in the drainage district, each with 50,000 gpm capacity.
Each hour, at full capacity, the pumps would be capable of delivering
178 million pounds of water. If this water contained 1 ppm of a given
nutrient, then 178 pounds of that nutrient would be added to the 31,000
acre lake every hour or approximately one ton in a 12 hour day of
pumping.

Other than the dissolved salts or nutrients, there was very little
debris or other solid matter observed being pumped into the lake. This
is contrary to some sensational press reports of "swill" being pumped
into the lake. In fact the water in the canals was generally clear,
much clearer than the lake. The water is clean enough so that it is
commonly used for mixing sprays and for overhead irrigation.

A comparison of analyses of samples taken from the St. Johns River
with samples from the Zellwood canals and Lake Apopka show generally
higher levels of solids, dissolved salts, and most nutrients (other than
phosphorus) in the river. The river is still clear and in good condition
for fishing and other recreational use.

Summary

Water samples were taken at frequent intervals from farm canals in
the Zellwood area and from adjacent Lake Apopka over a two year period.
Samples were analyzed for total solids, soluble salts, plant nutrients,
DDT and parathion.

During dry periods, the canal water was in approximately the same
range of solids and nutrients as the lake water. There was little








- 10 -


pumping of drainage water into the lake, except for short periods; hence
there was little contribution of nutrients to the lake during the dry
months.

During the summer rainy season, leaching of substances into the
canals raised the levels of solids, salts, and nutrients in the water
being pumped into the lake. Even with this fresh supply of nutrients
being added, the concentration of nutrients and solids in the lake
decreased with the dilution from the rain water during the summer.

No parathion was found in any of the samples. No DDT was found in
the lake water, but DDT was detected in several of the canal samples in
concentrations from 0.01 up to 0.25 ppm.

Other than the dissolved salts or nutrients there was generally
little debris or solid material being pumped into the lake. The canal
water was generally clearer than that in the lake.

Acknowledgement

The author wishes to express thanks to the following individuals for
their help which contributed greatly to the effectiveness of this study:
Mr. Doyle Golden and Warren Keane of the Chemical Division of the Florida
Department of Agriculture. Mr. Arch Hodges, Engineer, Zellwood Drainage
and Water Control District; Dr. James NeSmith, Soil Testing Laboratory,
Florida Agricultural Extension Service; and to Mr. John Lundquist,
operator of Fisherman's Paradise Resort.









- 11 -


Literature Cited

1. A.O.A.C. 1950. Official Methods of Analysis, Seventh Ed. :535.

2. Clugston, J. P. 1963. Lake Apopka, Florida, A Changing Lake and Its
Vegetation. Quar. Jour. Fla. Acad. of Sciences 26 (2):169-174.

3. Forbes, R. B. 1967. Water Quality Investigations, Zellwood Drainage
and Water Control District. Florida Agricultural Experiment Stations
Annual Report 1967: 226.

4. Forbes, R. B. 1968. Water Quality Studies, Zellwood Drainage and
Water Control District. Florida Agricultural Experiment Stations
Annual Summary Report. (In Press).

5. Heffstutler, K. K., J. E. Burgess and B. B. Glenn. 1965. Biological,
Physical and Chemical Study of Lake Apopka. Florida State Board of
Health, Bureau of Sanitary Engineering, Jacksonville, Florida.

6. Lane, E. 1966. Lake Apopka's Lingering Death. Orlando Sentinel,
April 3, 1966.

7. Swanson, H. F. 1963. A to Z. Zellwood Drainage and Water Control
District. Brochure, Orange County Agri. Center, Orlando, Florida.

8. Wadleigh, C. H. 1967. Agricultural Pollution of Water Resources.
Soil Conservation 33 (2) :27-30.

9. Walker, K. C. and C. H. Wadleigh. 1968. Water Pollution from Land
Runoff. Plant Food Review 1:2-4.




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