August 11, 1977
Dr. William L. Guyton
William F. Guyton & Associates
415 First Federal Plaza Building
Austin, Texas 78701
Please find enclosed the final draft of our
Very truly yours,
Joseph E. Davis
Manager of Projects
Ms.-Barbara A. Boatwright
Southwest Florida Water Management District
5060 U.S. Highway 41, South
Brooksville, Florida 33512
An Estch Company
August 4, 1977
Dear Ms. Boatwright:
Enclosed please find the final draft of our response to
your letter of February 17, 1977, as per Swift's review
with you May 26, 1977.
If there -is any additional data required to process our
permit application, please advise. As per our phone
conversation today, I assume the staff hearing will be
set for September 15, 1977.
Very truly yours,
Joseph E. Davis
Manager of Projects
Swift Chemical Company
PO Box 208
Bartow. FL 33810
Telephone 813 x33 7164
SOUTHWEST FLORIDA WATER MANAGEMENT DISTRICT RESPONSES
Question 1: Based on the proposed water balance for mining
and plant' operations, how much water will be
consumptively used? Please submit a water
balance (based on design capability) for plant
and mining operations showing sources and
quantities of water input to the system;
sources destinations, and quantities of water
recirculated in the system; and destination
and quantities of water discharged from the
Figure 1 is a diagram illustrating the process water balance for
the mining operation. It is based on current prospecting, pilot
plant and design information. Makeup of losses to the system are
the controlling factor in water demand. These losses have been
described in the Zellars-Williams, Inc. Preliminary Water Manage-
ment Plan, dated December 1976. The losses total 11,207 gpm on
an annual average. It is important to recognize that fluctuations
to these average losses will occur daily, depending on climatic
changes, metallurgical differences in the ore, and operating rates.
Of the 11,207 gpm needed to replenish the losses, 2,207 gpm will
be derived from interstitial moisture in the ore itself. The
remaining 9,000 gpm must be gathered from regional water supplies.
On the basis of current process metallurgy and engineering, Swift
believes that the process needs for high quality ground-water can
be limited to 4,144 qpm, utilized as a final product rinse and
flotation medium in the amine circuit. Other water requirements
in that circuit can be obtained from recirculated or surface water
sources. However, if deep wells are to be used as a portion
of the makeup requirements other than that introduced into the
amine Circuit, as shown on the diagram (2,551 gpm), this
water would also be introduced to the system in the amine
circuit since this is the best use of the resource.
Surface water has been included as a makeup water source, Preliminary
study of its diversion from either the East or North Fork of the
Manatee River are contained in Ardaman's report of May 23, 1977
and letter of May 20, 1977. The utilization has been limited to
2,000 qpm based on the feasibility of recovering this amount from
the East Fork of the Manatee using an off-channel weir, and the
demonstrated negligible effect on downstream users. Obviously,
any additional surface diversion would directly diminish the need
for ground-water used to makeup system losses (2,551 gpm).
Consumptive use, as presently defined (16J-0.02(5)) is "any use
of water which reduces the supply from which it is withdrawn or
diverted." The water balance as diagrammed in the response to
Question 1 shows actual makeup requirement, discounting matrix
moisture, of 9,000 gpm.' Utilizing the definition as a guideline,
we have categorized the total system losses, as follows:
Product Moisture 100%
Reject Pebble Phosphate 25%
Clay Absorbed Water 88%
Tailings Interstitial Water 0
Seepage Losses 25%
The water entrained in clay storage ponds has been considered
consumptive, because except for a small amount that may seep
into the surficial aquifer with time, the water is not recover-
able by ordinary means. Water entrainment in clays that are
mixed with sand during reclamation represents a different
situation. A much greater amount of the entrained water is
released to adjacent sand strata. These sands are connected
to the adjacent undisturbed sand aquifer, thus, this water is
available to the surficial system. To illustrate, assume the
The clay entrained water at 18% solids
With time, mixed with sand, the clays should
attain 30% solids and the entrained water
Thus, the additional water released from the
clays as a result of mixing with sand
From classical theory of consolidation,
approximately 50% of the released water
reaches the ground surface. This amount,
which is considered non-recoverable,
The remainder, which is released to the adjacent
sands and is thus non-consumptive
= 7,977 gpm
= 4,070 gpm
= 3,907 gpm
= 1,954 gpm
= 1,953 gpm
Swift will utilize the sand/clay mix in
restoration to the maximum but assume only
one-half will be thus treated, and the re-
mainder conventionally impounded. Thus, the
We have also assumed conservative positions in
the rejected pebble to be stored below ground,
and seepage losses. The total consumptive use,
utilizing the above assumptions and approach
is 9,000-3,532 gpm
= 5,468 gpm
This/co sumption is 61% of the total makeup requirements,
and/76% the water crop. Ninety-one percent (91%) of the
sysfe water uses will be recycled. The percentage will of
course be subject to seasonal climatic changes in evapotrans-
piration and rainfall.
On what basis is the requested consumptive use
reasonable (in terms of quantity and use),
beneficial and consistent with the public interest?
Based on prospecting and metallurgical data, a preliminary
engineering flowsheet has been devised that demonstrates the
need for an average rate of withdrawal to be used consumptively
(on an annual basis) to makeup system losses. We propose to
satisfy these needs from surface and ground-water supplies on
The reasonableness of the requested amount is based on the
demonstrated need as shown in the water balance, the adequacy
of supplies as shown in accompanying reports by Ardaman &
Associates, Inc. and W. F. Guyton & Associates, and an outline
for prudent management as shown by the plan for diversion and
the consumptive use schedule.
The beneficial use of the water resource is demonstrated by the
fact that, without the use of water as a medium for mining and
beneficiating the phosphate rock, this important natural resource
could not be feasibly recovered.
d4 W4f1,R I/L I
4t/R4 4' 6.
.4/9 R/zvse / d/NZ k/ e
pEre, WoE. W 4r l .
oJEA WE7RLL Mree
25 st ; ,
4'4 ; -.- 1
2000 ,4 ;
/2 0 7
*FdD PR. R'..
7"i/L/ GS DP~poslq *rJ
-- y^&o' 86: *J
_-/6/' r I#7 /#E !.."
- 7wl//jvc E-=7eWMe/ b W4tE
-- ~jAV~Ps& 1~~
J h 'r 96: /4' ,'
Z6ED / 34G 5 IR. '4 A'FA 4Ol /*7/M /T
y/VOs 4rE / h <,P-/ 1, "
THWafL R///./S /?1 1s5> // rH4 ^c/ R/S> /5 S5---7/
T4o rt/ RI;CycLE W/^R, OA/F k/TH ^ //// /r^17; r^^
WEIL 1rQTe ./.5 /S/50 FD Ad////r /Zord7^^/o./,
4211 su'ih P1161
- WILLIAMS, INC.
mWlalluri LiAIt I14 t*lr
Av*eo, *i**lol*, FrW4 II31
ODr lW Chlled A peohi Cilisn Aplieg l *i
4,l I /a4e~oreaZ.
Oil. ~ ~ Oirr jIr. tW b.I ,
- 7 "
It is important zo note that this production facility will
provide a continued supply of phosphate and fertilizer products
to Swift's customers, as first the Silver City mine, then the
Watson Mine, -in Polk County will be depleted in the 1980's and
1990's respectively. At the time of the Silver City completion
of mining, the present average ground-water withdrawal of about
7,700,000 gpd (5,352 gpm) will be discontinued. This phase
out will occur as early as 1983 or as late as 1988, depending on
future reserves depletion and addition. The Manatee mine will
insure a continued beneficial economic contribution to the area,
including employment, purchase of goods and services, and state
and local tax contributions vital to the public interest.
Finally, the reclamation plans as presently conceived by Swift
will consider methods whereby the future land use will include
long term provision for water use and control. Experimentation
conducted by Swift and other companies as a part of the joint
U. S. Bureau of Mines and Phosphate Council members research
program indicates that the proper mixing of sand and clays is
to some extent effective in releasing some of the water held
in the gravity settled clays. Swift plans to continue develop-
ment of this technique to increase water release from clay and
improve reclamation effectiveness. Lakes and other water fea-
tures will provide for long term runoff water retention, and as
reservoirs for use as potential water supply.
Question 3: To what extent will the requested withdrawal
interfere with any legal use of water exist-
ing at the time of the new application?
The proposed withdrawal will cause a drawdown of the potenti-
ometric surface in and around the area of the proposed mine
and will therefore cause pumping levels in nearby Floridan
wells to be lowered. The extent of this well interference
is illustrated in Figures 4, 5 and 6 which are discussed in
the answer to Question 6a.
The surface water withdrawal of 2,000 gpm from.the East Fork
of the Manatee River accounts for less than 5 percent of the
average annual excess flow at the Manatee Reservoir. Con-
sidering that present pumping from the Manatee Reservoir
utilizes only about 30 percent of the average annual excess
flow which passes through the reservoir, the amount proposed
for utilization by Swift will not interfere with this down-
stream user. No major additional legal user of water down-
stream is known.
Question 4 (a:) Will the proposed withdrawals of water cause
the rate of flow of a stream or other water-
course to be lowered below minimum rate of
flow established by the Board (16J-211(2)(a))?
The minimum rates of flow for each month, January through
December, at a given point on a stream, have been defined by
SWFWMD as 70 percent of the average of the five lowest monthly
mean discharges for the preceding twenty (20) years for the
four wettest months, and 90 percent of these values for the
remaining eight months. In the absence of a 20 year record
at the Swift site, calculations of these minimum rates of
flow have been made using the 1956 through 1975 water year
records from two nearby U.S.G.S. gauging stations. One of
these stations is on the Manatee River near Bradenton
(Station 23000) and has records extending from 1939 to 1966.
The other station (Station 22999.50) is on the Manatee River
at the State Highway 64 bridge, 2 miles downstream from the
confluence of the North and East Forks Manatee River, and has
records from 1966 to date. Using the above data normalized
by dividing the measured discharges by the watershed area,
the minimum monthly rates of flow for the East and North Forks
of the Manatee River at their exit from the Swift property
have been calculated and are presented in Figure 2. Also
shown in this figure are the average mean monthly flows based
on the 1966 through 1974 records at Station 22999.50 normalized
by dividing by the watershed area. Table 1 also presents these
data along with the resulting average monthly excess flows.
The average annual excess flow for the East and North Forks of
the Manatee River, as they exit the Swift property, are 16.18 cfs
(10.46 MGD) and 11.57 cfs (7.48 MGD), respectively.
MONTHLY FLOWS AT EXIT FROM
SWIFT PROPERTY IN CFS
East Fork Manatee River
North Fork Manatee River
Month Mean Minimum
Excess 14 cfs
EAST FORK MANATEE RIVER
iOrNTHLY FLOWS AT DOWNSTREAM END
OF SWIFT PROPERTY
FILE NUMBER 74-0271
AtDAMAN L ASOCQAIf
It is anticipated that 2,000 gpm (4.45 cfs) of the plant makeup
water could eventually be obtained from surface water, provided
water quality.proves to be adequate for the beneficiation
processes. This corresponds to 38.5 percent of the North Fork
Manatee River average annual excess at the downstream end of the
property, 27.5 percent of the East Fork Manatee River average
annual excess and only 16 percent of the overall Manatee River
average annual excess at the exit of the Swift site. Water
can be obtained from both or either of the North and East
Forks of the Manatee River, but appears most feasible on the
East Fork due to higher flow and nearness to the plant.
The withdrawal system can be designed so that water would not
be removed from the streams when stream flow was below the
highest of the minimum monthly rates of flow established by
SWFWMD. The highest.of these minimum rates of flow is 14 cfs
for the East Fork and 10 cfs for the North Fork of the Manatee
River. These flows occur in the month of August (see Figure 2).
The corresponding excess available averaged over a 12 month
period is 8.24 cfs and 5.90 cfs for the East and Vorth Forks
Manatee River, respectively (see Table 1). Only a portion of
this flow (about 4.45 cfs) will be diverted for consumptive
use by essentially skimming the high discharges during the wet
season, the volume used amounting to about 33 percent of the
water contributed to the Manatee River from the Swift site.
It is also conceivable to design the system so as to remove
a certain portion of the excess flow during the wet summer
months, e.g., a portion of the flow above say 25 cfs.
The 2,000 gpm withdrawal from the East Fork of the Manatee
River will, during some periods, reduce the rate of flow by
more than 5 percent (16J-4.06(5)(a)). As shown on Figure 2
and Table 1, however, this diversion will schedule withdrawal
proportionate to an amount in excess of minimum flow, and is
not excessive (see Ardaman letter of May 20, 1977).
Question 4.(bh): Will the proposed withdrawals of water cause
the level of the potentiometric surface to
be lowered below the regulatory level estab-
lished by the Board (16J-2.11(2)(b))?
No regulatory level has been established by the Board in the
area of the proposed mine site, and because of the relatively
low leakance estimated for the area, it appears unlikely that
regulatory levels will provide a practical method for control
of ground-water withdrawals.
Question 4-4tT: Will the proposed withdrawals of water cause the
level of the surface water to be lowered below
the minimum level established by the Board
There are no open bodies of water within the area of the proposed
mine site, and no minimum levels have been established by the
Board. On the basis of the estimated low leakance in the area,
pumping from the deep ground-water zones is not expected to
.produce noticeable effects upon water-related features, such
as lakes and streams.
Question 4td): Will the proposed withdrawals of water significantly
induce salt-water encroachment (16J-2.11(2)(d))?
The hydraulic testing of the deep mineralized zones (Hydraulics,
pp. 26-35, and Geophysics, pp. 30 and 31), combined with the
presence of low porosity evaporite deposits which have been
shown to exist to great depth (Geophysics, pp. 21-24), indicates
that the mineralized waters are tightly confined within a layered
system of impermeable rocks below the circulation that takes
place in the fresh-water zone of the Avon Park Formation, and
no noticeable vertical intrusion of mineralized waters is ex-
pected due to mine pumping.
Although upcoming, which is often associated with vertical in-
trusion, is not expected, a lowering of the head in the fresh
zones relative to that in the tightly confined mineralized zones
can be expected to cause some flow in the upward direction.
Based on the finite element layered model simulation (Hydraulics,
p. 71), an estimate of the overall movement of mineralized
water due to the mine is expected to be less than 10 times
the amount of water pumped.
As water-level measurements indicate (Hydraulics, pp. 63-65), a
relatively substantial head difference already exists between
the fresh and.mineralized zones in northeast Manatee County.
This head difference, which is thought to have been created
during the past 20 years or so of increasing agricultural
usage of ground water, has not produced noticeable effects
upon the quality of water pumped. This reinforces the con-
clusions that only relatively small amounts of mineralized
water can be drawn from beneath the fresh-water system.
Whether or not lateral encroachment at the Manatee County
coast will ever take place to any large extent will depend
upon both the size and location of ground-water withdrawals
within the county. At the present time in Manatee County, the
generalized hydraulic gradient at the coast is toward the Gulf
throughout the year. The potentiometric surface map of May,
1976, for example, which pictures conditions at a time during
the year when water levels have reached the lowest point,
indicates that the flow at the coast is toward the Gulf even
though substantial inland areas of the county were at or below
sea level at that point in time. During the fall and winter
months, after the rise in water levels takes place at the end
of the irrigation cycle and with the coming of the summer rains,
the net water movement throughout the county is essentially
The proposed Swift mine site is located approximately 20 miles
inland from the Manatee County coast. Based on the concept of
recharge through leakage from the surface, a withdrawal located
one mile from the coast would contribute approximately 40 or
50 times the inducement to encroachment as would a similar
withdrawal 20 miles from the coast.
So long as the hydraulic gradient at the fresh-water/salt-water
interface, averaged over time, is directed toward the coast,
there will be a net flow of fresh water toward the Gulf and
no general or extensive encroachment would be expected.
Under these conditions the proposed Swift withdrawal would not
be expected to "significantly induce salt-water encroachment."
Question Afe): Will the proposed withdrawals of water cause
the water table to be lowered so that lake
stages or. vegetation will be adversely and
Significantly affected on lands other than
those owned, leased, or otherwise controlled
by the applicant 16J-2.11(2)(e))?
Studies of the relationship between a lowering of the potenti-
ometric surface caused by pumping and a subsequent lowering
of the water table in the areas of Pasco and Hillsborough
Counties generally indicate that the leakage induced by the
created head difference must exceed the available recharge
(in this case assumed to be the water crop) before the water
table is noticeably affected. A head difference on the order
of 200 feet would be necessary to reach this condition in
northeast Manatee County, and the resulting level of the
potentiometric surface would be roughly 100 feet below sea
level. The present year-round average difference between the
water table and the potentiometric surface is on the order of
100 feet. The Swift withdrawal from the deep ground-water
zones is not expected to produce noticeable effects upon
water-related surface features, such as lakes, streams, and
vegetation-in the vicinity of the proposed mine since such
effects would be essentially controlled by changes in the
Mine pit dewatering will produce temporary effects on the
water level of surficial sands adjacent to the mining cut
(high wall). The water table aquifer is variable in com-
position and texture ranging from about 20-40 feet in thick-
ness. It consists generally of fine to medium sand, hardpan-
type sands, and slightly clayey fine sands at the top of the
phosphate matrix. A generalized average description would
include a 5-foot thick surficial fine sand overlying an
11-foot thick relatively impervius hardpan-type sand. The
latter layer is underlain by a medium to fine sand layer
averaging approximately 17 feet in thickness. These layers,
along with the upper few feet of the ore matrix would comprise
the water table aquifer system. The Swift field monitoring
program included installation of numerous piezometers and
observation wells. Evaluation of this data since 1975 shows
that during the wet season, the water table is essentially at,
slightly above or within a foot-of the ground surface. During
the dry season, the water table experiences a seasonal lower-
ing and is generally located 6 to 7 feet below the surface, i.e.,
within the hardpan layer. The water table drawdown due to de-
watering the mine pit depends on the thickness'and permeability
of the various strata comprising the aquifer, the span of time
that a pit is dewatered, the distance from the edge of the
mining pit and the amount of recharge. Figure 3 presents the
predicted water table drawdown during both the dry season (no
recharge) and the wet season (average recharge of 4 in/month).
The analysis has been made for two conditions (Case A and Case B).
In Case A the hardpan layer is assumed to be absent. In Case B
the hardpan layer is assumed to have a permeability of 4 inches
per month (4 x 10-6 cm/sec). The actual conditions at the Swift
site are intermediate between these two conditions and the actual
drawdowns are expected to be less than those shown for Case A
and greater than those shown for Case B. As shown in Figure 3
*mining will not change the water table except locally in areas
surrounding those pits being dewatered. Because moisture re-
tained within the capillary zone after each rainfall is still
available for plant uptake, vegetation is not expected to be
adversely affected. There are no dry weather ponds or lakes
within 1000-feet of the property boundaries water levels will
return to their natural levels once the mining area is reclaimed.
Question,-: Will the amount of consumptive use exceed the
water crop of lands owned, leased, or other-
wise controlled by the applicant (16J-2.11(3))?
No. The water crop as defined by the district (16J-2.11(3)),
is 1000 gal/acre/day. For the Swift property this equates
to 10,393,740 gallons per day. The consumptive use as
calculated in the response to Question 1 is 7,873,920 gallons
(^cf pr^^ -IO~
0 /K 1o2c m/sec
----- WET SEASON (RECHARGE = 4"/MONTH)
S---0-- DRY SEASON (NO RECHARGE)
0 ______ 0 ELAPSED TIME (MONTHS)
0 200 400 600 800 1000 1200
DISTANCE FROM EDGE OF PIT, feet
0 FINE SAND
K = 10-2cm/sec
n = .25 ,,
10I / HARDPAN
.K = 4xl0-6cm/sec
|z I ne = -25
MEDIUM FINE SAND
S20- K = 10-2cm/sec
ne = 25
Ili RECHARGE = 4"/MONTH
S- ---- WET SEASON -.
-- 0- -- DRY SEASON
!) [) ELAPSED TIME (MONTHS) :
0 200 400 600 800 1000 1200
DISTANCE FROM EDGE OF PIT, feet
DRAWDOWN vs DISTANCE AT VARIOUS TIMES
AFTER PIT IS OPENED AND DEWATERED
SWIFT CHEMICAL COMPANY
MANATEE COUNTY, FLORIDA
FILE NUMBER 74-027 FIGURE 3
AEDAMAN & ASOCIATES
Question 64a): To what extent will the proposed withdrawal
of water cause the level of the potentiometric
surface under lands not owned, leased, or
otherwise controlled by the applicant be
lowered (16J-2.11(4) (b))?
A finite difference computer model based on aquifer properties
determined from field tests has been used to compute drawdowns
associated with the projected withdrawal needs of the mines.
Although this model does not simulate the anisotropic char-
acter of the aquifer in the immediate vicinity of the pro-
posed well field, it does include a higher transmissivity
for areas within a distance of approximately 1 mile from the
well field than for outlying areas, based on results of the
long-term pumping tests conducted at the mine site. The
leakance used for these calculations was 10-4 gpd/ft3.
The cone of depression shown on Figure 4 represents the
effect of a 9000 gpm withdrawal during the first 2 years of
mine operation, when the total supply is needed from the
Floridan aquifer. After the first 2 years of operation,
approximately 2000 gpm is expected to have been developed
from surface supplies to offset pumping from the Floridan
aquifer, and the reduced cone of depression shown on Figure
5 represents the effect of the withdrawal reduced to 7000
gpm. The depression shown on Figure 6 represents the com-
bined effect of pumping at a rate of 7000 gpm, coincident with
recharge from the shallow aquifer of approximately 2100 gpm
through connector wells located over the mine property, pro-
vided this recharge proves feasible. The drawdowns illustrated
on Figure 6 would be expected to prevail for the majority of
the life-of the mine.
Drawdown at the boundary of an area equivalent in size to
the Swift property, but which has the shape of a constant
drawdown contour of the depression caused in the potenti-
ometric surface, would be expected to be about 6 feet at the
end of the first 2 years, and about 3 feet after the surface
supplies and recharge wells have been put into operation.
Drawdown Associated with 9, 000-gpr Withdrawalat the End
of Two Years of Mine Operation
0 1/2 I
Drawdown Associated with 7,000-gpm Withdrawal, Assuming
No Recharge from Connector Wells
0 1/2 I
Figure 6. Drawdown Associated with caobined 7, 000-gpm Withdrawal and 2,100-gpm
Recharge from Connector Wells Located over Mine Property
Question frb): To what extent will the proposed withdrawal
of water cause the levels of the water table
under lands not owned, leased, or otherwise
controlled by the applicant to be lowered
The proposed ground-water withdrawal from the Floridan Aquifer
is not expected to produce a measurable lowering of the water
table on the Swift property, or on lands that are not controlled
Mine dewatering adjacent to the property perimeter will cause a
temporary lowering of the surficial aquifer. As shown in Figure 3
the water table may be affected to distances of up to 1,000 feet
during a prolonged 4 month period without recharge.
Question 6-6): To what extent will the proposed withdrawal
cause the level of the surface of water in
any lake or other impoundments to be lowered
The proposed withdrawal is not expected to produce a measureable
lowering of.any surface body of water on the Swift property or
on lands not controlled by Swift.
Question 6&(): To what extent will the proposed withdrawal of
water cause the potentiometric surface to be
lowered below sea level (16J-2.11(4)(e))?
Using a ground-water withdrawal rate of 9,000 gpm, the maximum
drawdowns within the proposed well field are expected to be
approximately 12 to 16 feet. The lowest measured level of the
potentiometric surface in the vicinity of the proposed mine was
approximately 7 feet above mean sea level in May 1975. In
May, 1976, the low water level was approximately 12 feet above mean
sea level. Under present conditions, the pumping levels at
interior wells in the well field would be expected to be 2 to 8
feet below sea level for several weeks during late spring each
year. During the fall and winter months, pumping levels would
be expected to be roughly 30 feet above sea level.
Question -: Will Swift request exemptions as provided in
(16J-2.11(5))? If so, what exemptions will
be requested and what will be the basis for
Swift will ask that the Board grant exceptions to the provisions
of paragraphs 4(a), 4(b), 4(c) and 4(e) of the Southwest Florida
Water Management District Rules.
Paragraph 4(a) Must not reduce rate of flow in stream or
other water course by more than 5 percent.
The diversion of 2,000-gpm surface water from either the East
or North Fork of the Manatee will reduce the total flow during
some periods by more than 5 percent. The withdrawal schedule
as shown on Table 1, however, is a reasonable and beneficial
use of the water in that it allows a reduction in ground-water
pumping, allows for maintenance of minimum flows, and will
create virtually no effect on downstream water users, including
the Lake Manatee Reservoir.
Paragraph 4(b) Must not cause the level of the potentiometric
surface under lands not owned, leased, or other-
wise controlled by the applicant to be lowered
more than five feet (5').
During the first 2 years of mine operation, drawdowns of
about 9 feet are expected at the property boundary just
north of the well field, and about 7 to 8 feet are expected
at the boundary to the east of the well field. As other
sources of water are developed to offset the withdrawals,
however, the drawdowns at these boundaries are expected to
be reduced to about 5 to 6 feet and 4 to 5 feet, respectively.
At that time, the drawdown at the boundary of an equivalent
area of the mine are expected to be about 3 feet.
Paragraph 4(c) Must not cause the level of water table under
lands not owned, leased, or otherwise con-
trolled by the applicant to be lowered more
than three feet (3').
Mine dewatering near the property boundaries can lower the
water table more than three feet up to seven hundred feet
away from the-edge of the mined pit. The dewatering will
be temporary and have negligible effect on vegetation -
probably similar to the droughts induced by the seasonal
water table lowering of about eight feet. If granted this
exception, Swift will (1) secure approval of the affected
property owners, or (2) provide a perimeter ditch to
recharge the surficial aquifer.
Paragraph 4(e) Must not cause the potentiometric surface to
be lowered below sea level.
Where inland areas, such as northeast Manatee County are con-
cerned, this provision primarily guards against the possibility
of vertical intrusion of highly mineralized water from deep
zones. As indicated in the response to Question 4(e) of the
SWFWMD letter, test results indicate that the mineralized water
at depth below the mine site is tightly confined within a
layered system of impermeable rocks, below the circulation that
takes place in the fresh-water zone of the Avon Park Formation,
and no noticeable vertical intrusion of mineralized water is
expected due to mine pumping.
Question 8: What is the proposed phosphate production rate
from the commencement to the time when the
project will be operating at full capacity?
Swift plans to commence activities at the full mine design
capacity of three million tons of phosphate rock annually by
Preliminary studies of the possibility of recharging water to
the Floridan Aquifer from the sand of the shallow aquifer are
now under way. Quantitative estimates based upon pumping test data
obtained for the shallow sands and upon the distribution of
overburden thickness of the mine property, indicate that
connector wells should be able to recharge at least 2-3 MGD.
Any reduction in evapotranspiration due to the dewatering of
the surficial. sands would be expected to increase the amount
available for recharge. Analysis of water samples taken
from the sand indicate that the total solids content, and
generally the amount of each of the major ions in the water,
is lower for the shallow aquifer than for Floridan water.
However, data is not yet available regarding amounts of
various trace elements established by the United States
Environmental Protection Agency as significant contaminants.
Samples are being taken and analyzed for these trace ele-
ments at this time. Once the water quality has been estab-
lished and is considered acceptable for recharge by appropriate
federal and state agencies responsible for ground-water
quality, pilot recharge well sites will be planned for two
locations on the mine site reflecting maximum and minimum
thicknesses of the shallow aquifer. The flow into each
pilot well, as well as the extent of dewatering effects
surrounding the well, will be monitored to determine the
variability associated with seasonal wet and dry periods,
and thus, provide a basis for more accurate predictions of
total recharge available.
Iy Ardaman&Associates, Inc.
Consulting Engineers in Soil Mechanics, 177
Foundations, and Materials Testing May
File Number 74-027
Swift Agricultural Chemicals Corp.
c/o Zellars & Williams
4222 South Florida Avenue
Lakeland, Florida 33803
Attention: Mr. Michael Zellars
SUBJECT: Consumptive Use Permit, Question 2a.
Based on preliminary analyses by Zellars & Williams, as much as 3500 gpm
(7.8 cfs) of surface water could be utilized in the beneficiation process.
This water could be diverted from either the East Fork or the North Fork
of the Manatee River or both. As described in our letter of March 7, 1977,
the average annual excess flow, as defined in the SWFWMD regulations, for
the East and North Forks of the Manatee River as they exit the Swift property
are 16.18 cfs and 11.57 cfs, respectively. However, not all of this water
can be recovered.
The present design concept is to skim off a portion of the high flows during
the wet season through an off-channel spillway and store the water in a man-
made lake for future use. If the spillway weir is designed to remove only
that portion of the water above the highest of the minimum monthly rates
of flow, then the available excess for the East and North Forks will be reduced.
to 8.24 cfs and 5.9 cfs, respectively (see Table 1 of the above referenced
letter). Because not all of this excess flow can be diverted, the amount
of recoverable water will be reduced even further. Without detailed analyses
it is not possible to predict the total amount of water which is recoverable.
However, it is reasonable to expect that at least 30 to 35 percent of the above
excess (1900 to 2200 gpm) can be practically recovered and it may be possible
that the total 3500 gpm can be obtained from surface sources.
Assuming that a total of 2000 gpm of surface water is utilized in the beneficiation
process, a reservoir of 3000 acre-feet would be sufficient to collect the excess
surface water during the wet season for use throughout the remainder of
6015 RandolDh Street, Post Office Box 13003, Orlando. Florida 32809. Telephone (305) 855-3860
Offices in. Bartow/Cocoa/Fort Myers/Orlando/Sarasota/,Tallahassee
Swift Agricultural Chemicals Corp. -2-
File Number 74-027
It should be noted that 2000 gpm (4.45 cfs) is only about 33 percent of the
average runoff from the Swift property into the Manatee River and accounts
for only about 4.5 percent of the average annual excess flow at the Manatee
Reservoir. Considering that present pumping from the Manatee Reservoir
utilizes only about 25 percent of the average annual excess flow which passes
through the reservoir, the amount proposed for utilization by Swift does not
appear to be excessive.
If there are any questions concerning the above, please
ARDAM N & ASSOCIATES, INC.
Anwar Z. Wissa, Sc.D.
ohn E. Garlanger, Ph.D., P.E.
Florida Registration No. 19782
cc: Joe Davis
do not hesitate to
1EW F Ardaman & Associates, Inc.