PROOF OF CONCEPTS
ADDENDUM
TO GILIO’S GENERAL PUBLIC PLAN G FOR FULL EVERGLADES RESTORATION
3.SLOTTED WEIR
JL Gilio.06.12.2016
ACTION ITEM: USACE NEEDS TO CONSIDER NOW AS DUKE HARDENING IS ON-GOING.
PLAN G. ELEMENT 3.
ONGOING USACE HERBERT HOOVER DIKE VERTICAL
HARDENING[CONCEPTUAL]
Without reinforced dike, existing materials- marl
Rock and muck at 15- 17 ft. NGVD would breach]
SLOTTED WEIR
CLEANER
LAKE OUTFLOW
SETTLED LAKE
MUCK/EAV
MODIFIED BY JL GILIO FROM USACE
ADVANTAGES AND DISADVANTAGES OF SLOTTED WEIR WITH BOTTOM DROPPING VERTICAL RISERS
ADVANTAGES POST HHD HARDENING
1. PERMITS A VARIABLE HEAD DISCHARGE FROM THE LAKE TO OUTFLOW SOUTH INTO A “RESTORED” FLOWING/STORAGING/TREATING
WETLAND ON FORMER EVERGLADES, NOW EAA FARMED LANDS.
2. WITHOUT USE OF RISERS, OUTFLOW MORE SIMILAR TO NATURAL HYDROPERIOD OUTFLOW OF ORIGINAL EVERGLADES.
3. WITH RISERS, CONTROL THE WATER VOLUME OUTFLOW SOUTH AND TOTAL PHOSPHORUS LOADING TO THE CAPACITY AND/OR TOTAL
PHOSPHORUS LEVELS IN THE RECEIVING WCA’S. THE TIME VOLUME DELAY WOULD ADD DOWNSTREAM CAPACITY FROM
EVAPOTRANSPORATION AND /OR TREATMENT TIME BEFORE RECEIVING ADDITIONAL LAKE OUTFLOW.
4. WITH RISERS DISCHARGE CONTROLLED VOLUMES BASED ON RESTRICTED WEIR LENGTHS BELOW 15 FT. NGVD, TO MAINTAIN THE
“RESTORED” EVERGLADES WETLAND IN A “WET” STATE; TO PREVENT DRY CONDITIONS THAT UPON REWETTING WOULD PRDUCE A HIGH
NUTRIENT FRONT DOWNSTREAM. AND STILL MAINTAIN A LAKE LEVEL NEAR OPTIMAL STAGING.
5. TOTAL LENGTH OF 7 MILES AND 1.5 FT. HEIGHT AND 10% PER DAY DRAINAGE FLOW FROM LAKE’S DRAINAGE AREA FOR THREE DAY
DESIGN 100 YR. STORM EVENT WOULD CAUSE A RISE OF APPROXIMATELY 1.5 FT. WHEN THE SLOTTED WEIR IS FULLY OPEN AND
DOWNSTREAM TREATMENT WETLANDS CAN SAFELY RECEIVE SUCH VOLUMES. IF THE REVISED LORS FOR THE HARDENED HHD CAN NOT
HANDLE LAKE STAGINGS HIGHER THAN THE 2008 LORS, AND DOWNSTREAM SOUTH STORAGE/TREATMENT CAPACITY IS NOT AVAILABLE,
THEN THE CURRENT DISCHARGES TO THE RIVERS WOULD BE AVAILABLE AS EMERGENCY OUTLETS.
6. A PDF EXCEL CALCULATION WILL BE SUPPLIED AND ADDED TO THIS ADDENDUM.
7. THE SLOTTED WEIR CONCEPT WOULD ENHANCE THE MONEY SPENT ON THE HHD HARDENING.
8. LAKE OKEECHOBEE’S SEASONAL FLUCTUATIONS WOULD MORE RESEMBLE A NATURAL DAMMED LAKE RATHER THAN A RESERVOIR.
REDUCEDLAKE FLUCUATIONS WOULD RESULT IN A MORE STABLE EAV LITTORAL ZONE WHICH IN TURN WOULD IMPROVE WATER QUALITY,
INCREASED EVAPOTRANSPIRATION –A VOLUME REGULATOR  INCREASED EVERGLADES RAIN MACHINE- IMPROVED/ MORE STABLE
FISHERIES HABITAT AND BIRD NESTING/ROOSTING/FEEDING. MANY OF THESE BIRDS ARE ENDANGERED OR OF FEDERAL
SPECIAL CONCERN. NOTABLY, A LESS ERATIC LAKE LEVEL COULD ENHANCE THE HABITAT AND FEEDING OF THE EVERGLADES KITE.
9. PROVIDES USACE FINE TUNING OF LAKE LEVELS. AND STILL MAINTAIN ICW USE.
10. REDUCED OPERATING AND MAINTENANCE COSTS OF RIVER DISCHARGE PUMPS WHEN SLOTTED WEIR OPERATED IN OPEN CONDITION.
11. EXPECTED DEVELOPMENT OR ENHANCEMENT OF A LITTORAL ZONE FILTER UPSTREAM OF SLOTTED WEIR. THIS ZONE WOULD INCREASE
LAKE LITTORAL HABITAT AND FILTER OUT SOME OF THE SUSPENDED SOLIDS TO REDUCE THE POLLUTANT LOADING OUTFLOW TO THE
“RESTORED” EVERGLADES FLOWING/STORAGE/TREATMENT WETLAND.
DISADVANTAGES POST HHD HARDENING
1. INCREASED COST FOR SLOTTED WEIR AND RISERS. ESTIMATED HERE AT $1.0 TO 1.5 BILLION.
2. NEED FOR BRIDGED REPLACEMENT OF SR 80. ESTIMATED AT $0.8 TO 1.2 BILLION.
3. POSSIBILITY OF COMBINING BRIDGE ABOVE SLOTTED WEIR TO REDUCE COSTS.
Lake staging and wading bird correlation indicates that
The higher water levels 13 to 15 ft. NGVD result in
Higher resident bird foragers and flock size.
The employment of a slotted weir at 15 ft. NGVD would
Enhance this correlation many times over.
Modified from SFWMD
THE POTENTIAL FOR EVERGLADES PLANT AND ANIMAL RESTORATION BASED ON A MORE NATURAL HYDROPERIODICITY
IS ATTAINABLE WITH INCORPORATION OF THE SLOTTED WEIR INTO THE REHARDENED HERBERT HOOVER DIKE.