. I ^' . . . . .... . . . .... . . . .. -o . .... ..
I .\ HOUSTON. TXAS 77001
\ ENGINEERS CONSTRUCTORS
^ ..-1 ^ September 29, 1972
Mr. W. H. Rogers, Jr.
Chief Engineer Power Plants
FLORIDA POWER & LIGHT COMPANYf
P. O. Box 3100
Miami, Florida 33101
SUBJECT: MAR1ATEE COOLING WATER R. ESERVOIR
DIVERSION OF WATER FROM- THE
LITTLE MANATEE RIVER
Dear 1Mr. Rogers:
In accordance with the conversation between your Mr. R. J. Gardner
and our Mr. C. W. Weber concerning the diversion of water from the Little
Manatee River, we include the following information regarding the diversions
from the river.
A historical daily operation of the reservoir has been performed over
the April 1, 1939 through December 31, 1971 period when flows were recorded
in4 t4, '4- n I
in the Little Manatee River at the USGS gage near Wimauma at State Highway
301 downstream from the point of diversion. This daily operation was
performed with a maximum diversion capacity of 150 cfs. Also no water was
diverted from the river when the flow in the river at the point of diversion
was less than 40 cfs.
Pertinent facts concerning river flows that would have occurred during
the 1939-1971 period if the reservoir would have been in operation are as
1. The year of the lowest total flow recorded in the river at the
USGS gage near Wimauma during the 1939 to 1971 period was
calendar year 1956. The flow passing the gage that year was
ENV'L. AFFAIRS 35,900 acre-feet. If the project had been in operation that
NRK W year, 12,100 acre-feet would have been pumped from the river.
There would also have been a slight reduction in flow to the
j WJB .... __ river resulting from a reduction in drainage area contributing to
Jp_ the river by the presence of the proposed reservoir.
L ~ ~ .'-n...,
FiLE- --2, The year of the highest pumping from the Litt3e Manatee River
would have been 1_62. The flow passing the USGS gage that year
was 157l0^0 acre-feet. If the project had been in operation
that year, 26,700 ccre-feet would have been pumped from the
river. There would also have been a reduction in flow to the
.river rc .ltin from a reduction in drainage area contributing
\ REC t\ tj to the river by the presence of the proposed reservoir. Releases
of excers rainfall (3,>?. acre-feet) would have been made from the
,.T 2 ,.., pilli y but at a .at l.ss th"n v.ich would have occurred if
the reservoir was not present.
Mr. W. H. Rogers, Jr.
September 29, 1972
13. The year of the lowest net pumpage from the river would have been
1955. The flow passing the USGS gage that year was 92,000 acre-
feet. If the project had been in operation that year, 12,600
acre-feet would have been pumped from the river but 3,500 acre-
feet would have been released from the reservoir back to the river.
4. Over the period of record the long term average pumping rate from
the river less spillage from the reservoir would have been
approximately 13,000 acre-feet per year,
Based on the calculated historical operation of the reservoir, a Dumping
rate of 12,100 acre-feet per year could be anticipated during a dry calendar
year, a maximum turning rate of 24,700 acre-feet per year could be
anticipated during a wet calendar year and an average net pumning rate from
the river of 13,000 acre-feet per year could be anticipated. Therefore,
Florida Power & Light Company may be limited to a maximum annual diversion
of 25,000 acre-feet at the pumping station and have a corresponding right
to divert approximately at least 12,000 acre-feet in a drought year when
the flow in the river exceeds 40 cfs.
If there are any questions concerning this matter, please contact us.
'Very truly yours,
C. L. Pick
cc: J. A. Lasseter
C. B. Amos
A. D. Schmidt
C. A. Sundstorm
W. J. Barrow-
C. W. Weber