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EvergladesHUB Online (home) > Lake Okeechobee > The WATERSHED   Statistics Links P-Distribution  

 
What's New

Watch for the developing "battle of Lake Okeechobee" !
Read more

LOOK AT FACTS

P-removal

Lake Okeechobee sits right in the centre of the Florida peninsula (satellite view).
During the wet season, the Lake collects, retains and drains almost 5 feet of rainwater precipitation





SCIENCE PAPERS




US Geological Survey

SFWMD
South Florida Water
Management District
       

LAKE OKEECHOBEE HAS 9 MAJOR WATERSHED AREAS - -
Mouseover watersheds for LAND-USE and P-LOAD:
   
Watershed areas of Lake OkeechobeeLO Watersheds

urban development
Upper Kissimmee

Lower Kissimmee

Fisheating Creek

Taylor Creek/Nubbin Slough

Lake Istokpoga

Indian Prairie

East Lake O. Basins

West Lake O. Basins

Everglades Agricultural Area (EAA)



They all, some more, some less,
channel urban and agricultural polution to the Lake.
And YES, apart from Nitrogen and other kinds, the source of the main problem :

pumping into the tributary

vegetable fieldssugar canecitrus orchardscattle farmingdairy farming

Remove it !

It originates primarily from urban wastwaters and agricultural activities in the Lake watershed :
.
About 5,600 tons of P is imported and applied in Lake Okeechobee watershed every year
- this is enough to meet Lake Okeechobee's TMDL (P goal) of ~105 t/y, for more than 53 years !
"Legacy" Phosphorus - an estimated 190,000 tons of P have already been deposited in the Lake
Okeechobee watershed - - this is enough to meet Lake Okeechobee's annual TMDL (P goal) of ~105 t/y,
for 1,800 years !
The Lake is receiving 656 tons of P per year (2009) < - - > 105 t/year is the recommended maximum.

The Lake just cannot cope with the P overload that keeps pouring in !
This is why the lake water is not welcomed anywhere - creating havoc in the estuaries where it curremtly goes
(via the Caloosahatchee and St. Lucie River) - let alone in P-sensitive Everglades located downstream.

Lake Okeechobee Watershed Statistics
Lowlying flat countryside - WET and DRY seasons 1-foot rainfall =
3 feet lake rise
Used by beef cattle ranching (pastures), dairy operations; vegetable, citrus, cane farming citrus orchards
Watershed Surface Area
3,062,000 ac.
4,785 sq miles  
Water fed into the Lake
2 million acre-ft/y
Average LO Depth

9 feet

Maximum LO Depth
12 feet
Minimum LO Elevation
9 feet
Maximum LO Elev.
19 feet
81% of the phosphorus entering Lake Okeechobee comes from its northern watershed.
 
Over 90 %t of the total phosphorus entering the Lake from the north originates from Agricultural lands.
 
10% of the phosphorus entering the Lake comes from the southern Everglades Agricultural Area (EAA), which is dominated by sugarcane production. Since most of EAA lies below the level of LO this water is back-pumped, the practice currently largely discontinued. However, the legacy phosphorus from past years of routine back-pumping is still sitting in the Lake.  
P import
contribution
Improved pasture fertilizer
29 %
Dairy
22 %
 
Truck crops
22 %
Citrus
9 %
 
17 % of this fertilizer ends up as run-off in Lake Okeechobee  
P run-off
contribution
Improved pastures
58 %
Citrus production
9 %
 
    Dairy production
8 %
 
           
           



























Watershed land use and Phosphorus
P-landuse
P-load
 
Some land uses contribute high amounts of "loose" Phosphorus - it escapes into streams and canals feeding LO.
E.g. check high P contributions from "Improved Pastures"
(24.5%)", "Citrus" (18.1%), "Row Crops" (7.8%). Conversely, BIG "Natural Areas" contribute relatively little P !
LO watershed land use
P contribution from the LO watershed
P runoff














Phosphorus soil deposits
P-imports
P in soils
Legacy P in soil
The problem is with "legacy" phosphorus deposited in soil over the decades. It is present there in highly mobile forms that leach easily and run off with rain water.
Net Phosphorus imports - North LO watershed
Conceptual legacy P sources in soil
"Legacy-P" is greater than native P and in mobile forms that are easily released





















Useful Links for information on Lake Okeechobee Watershed
REPORTS
WEBSITES
ACE-CERP website  

SFWMD - LO Watershed

Florida Dept. Environ. Protection -LO Basin Status Reports
2007 South Florida Environmental Report (SFER, SFWMD) EPA - Evaluation of Legacy Phosphorus in the Northern Lake Okeechobee Watershed (SFWMD)
Watershed Assessment Model (WAM)
LakeOkeechobee.org: Phosphorus
LakeOkeechobee.org: Cattle ranching















LOOK Lake Okeechobee
WATERSHED

Possible Remedies

STOP spreading around Phosphorus !
(see "Lake Okeechobee " problems).

Only when the contamination from the LO watersheds is under control could we hope for healthier Lake.
To clean the watershed is a complex task requiring stringent measures rigorously enforced.

Read more

Proceed along 2 lines:
- EDGE-OF-FARM water collection and treatment; and
- REGIONAL water retention/ detention schemes and larger-scale treatment (RASTAs)

EDGE-OF-FARM actions:
Construct water retention/ detention and treatment facilities handling the farm land run-off
Stop harmful application/ dumping of (sludge) "boiosolids"

Legislate the use of slow-release fertilizers applied with regard to meeting the pollution standards, not crop optimum
Legislate P as a "controlled substance"
To provide for monitoring and control of its import and application
Discontinue the practice of feeding P supplements to cattle

Impose well selected (for their effectiveness) strict and mandatory Best Management Practices (BMPs) on farms

REGIONAL remedies:
Acquire land for construction of adequate and well positioned new RASTA units

Construct enough water Reservoir-STA treatment (RASTA) combination capacity
To provide for water storage and treatment

Limit and stricly control the urban growth and sprawl

Introduce and enforce strict urban/domestic and industrial wastewater treatment criteria

cattle pollution

urban pollution





Algal bloom
Water quality: Toxic alagal bloom in northern LO where the phosphorus keeps pouring in through the Lake tributaries collecting it from the urban wastes and agricultural fertilizers When the algae die off, they deposit the biomass P in the Lake muds that keep accumulating.

Old Kissimmee
Kissimmee River flood plain
:
Prior to canalization, water could flood over and take months before it reached Lake Okeechobee. Then a straight canal has sped up the flow, taking the silt and contamination into the Lake. The new project has returned the river back to its original course, 56 miles of the canal filled in just recently.




Examples of desired P reductions
LO Watershed Basins P-reduction target (to meet LO-TMDL)
Fisheating Creek 80% (55 to 11 t/y)
Taylor Creek
Nubbin Slough
94% (86 to 5 t/y)
Lower Kissimmee 77% (77 to 18 t/y)
Upper Kissimme 49% (92 to 47 t/y)
Lake Istokpoga 50% (30 to 15 t/y)
 
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