Tag Archives: EyeonLakeO

How Much Water Has Flowed Backwards From C-44 to Lake O?

My recent post about “Holding Lake Okeechobee’s Algae at Bay” got a lot of responses with a few questioning whether the algae bloom in Lake O off Port Mayaca was caused by the waters of C-44 flowing back into the lake.


~A valid question.

I do not know the answer to this question, but I do know flights over the C-44 canal in 2019 have shown no visible algae blooms, but many in the lake with some right off Port Mayaca. Nonetheless, we know the  C-44 is full of nutrient pollution.

Today I want to share a chart from my brother Todd Thurlow’s website http://eyeonlakeo.com/ as well as our back and forth on the issue of how much water has been put into Lake Okeechobee from C-44 so far this year rather than going into the St Lucie River. The ACOE can flow C-44 flow both ways…

Be sure to read “Summary of Query Results” below for the answer.

Todd: Jacqui, I changed my DBKey on my daily spreadsheet to S-308 just to see what it would spit out.  See below.  It looks like S-308 has sent a net 17billion gallons of C-44 basin water (over 54,000 AF) into Lake O this year.  I am pretty sure that means we get a “free” 17billion gallons in our direction before it is considered “Lake Water”.

Jacqui: Todd did the ACOE start sending the C-44 canal water back to Lake O May 29th? Looking at the chart this is what I see. 

Todd: There has been little flows all year as can be seen on the chart too but the big flows started on May 13 at -2042cfs.  There was a pause between June 4 and July 30.  Then is started again with a few days off here and there.  Here is the data that is summarized in that chart.

The May 29 date that you might see (its actually May 20) is where the “Cumulative Total Discharge” graph crosses the zero axis?  That is where the net flows for the year were back to zero.  In other words, it took from May 13 to May 20, 8 days of westward flow, to cancel out all of the net eastward flow for the year.

SFWMD canal and basin map. C-44 can run east to the St. Lucie or west to Lake Okeechobee.

These DEP canal summaries are no longer available on-line but remain good references even though written in 2001.



Top 25 Discharge Years to the St Lucie and Calooshahatchee

S-80 Spillway at St Lucie Locks, Top 25 Discharge Calendar Years, 1953 to 2019. Source SFWMD DBHydro, courtesy of Todd Thurlow.

“Destruction by the Numbers” Lake O & C-44; S-79

Although the St Lucie River was declared “impaired” by the state of Florida, in 2002, the damage has been cumulative. The above chart created by my brother, Todd Thurlow, displays the damaging discharges from Lake Okeechobee and the C-44 basin at S-80 spillway, St Lucie Locks and Dam, for the top 25 discharge calendar years on record, 1953-2019. (http://www.eyeonlakeo.com/DischargeDataandTools/Top25_S-80_DischargeCalendarYears.htm, source: DBHydro: https://www.sfwmd.gov/science-data/dbhydro)

Shockingly, the worst year, 1960, displays 3,093,488 acre feet of water coming through S-80 into the St Lucie River/Indian River Lagoon. For comparison, the highest year in the past decade was 2016 at 857,529 acre feet.  ~A difference of 2, 235,959 acre feet.

We know now that an “acre foot” is an easy calculation, “one foot of water covering one acre of land.” 3,093,488 acre feet of water would have just about covered St Lucie, Martin, Palm Beach, and Broward counties as the acreage of these counties combined adds up to 3,293,440 acres. Hard to believe!


Even though in 1960, the lake was not yet prone to massive cyanobacteria blooms, fresh water itself is destructive to a brackish estuary, and over three million acre feet discharged into the river by, what would have been at that time, the Central and South Florida Flood Control District, (the predecessor to the South Florida Water Management District), must have wiped out just about everything.

Of course the question is: “Why such high a high number in 1960?” One would deduce, that the primary reason would be because there were three tropical storms and one hurricane that crossed over Florida during this era. According to NOAA’s Tropical Cyclone Rainfall in Florida chart: Judith, October 1959, 7.90 inches; Donna, September 1960 13.24 inches; Florence, September 1960 15.79 inches, and we do not know for the Unnamed 1959 storm.(https://www.wpc.ncep.noaa.gov/tropical/rain/tcflorida.html)

But this is conjecture…

Going back to Todd’s graph, you’ll  notice that thirteen out of the twenty-five years listed had higher discharge number than 2016. Sobering, isn’t it? Staggering numbers, for a river that by Nature was never connected to Lake Okeechobee, and only a portion of the so-called C-44 Basin. We have drowned her, indeed…

Hurricanes 1959, 1960 NOAA, courtesy of Todd Thurlow.

Now for one final question.

The Caloosahatchee has data too, but only for years 1967-2019. Thus the Caloosahatchee’s  highest year for discharge of its top 25 years is 2005, at 3,731,056 acre feet;  followed by 2016, at 2, 950,926 acre feet and so on. Please click on the graph.

So what about the missing thirteen years of 1953-1968? Where did this water go? Did it go to the St Lucie? Was the Caloosahtchee off-line? Did it go through the Calooshahatchee but was not recorded? These are questions I cannot answer. But in any case, both rivers need a break, or they shall break themselves. History allows us to see the long-standing destruction and ecological disregard for our treasured Northern Estuaries.

S-79 Spillway on Caloosahatchee at Franklin Lock and Dam, Top 25 Discharge Calendar Years, 1967-2019, courtesy Todd Thurlow.

Above chart larger format: http://www.eyeonlakeo.com/DischargeDataandTools/Top25_S-79_DischargeCalendarYears.htm

Basin map SFWMD. Before it was connected by canals, the St Lucie River was a large fresh water “stream” that ran into the Indian River Lagoon.
Structures along the Caloosahatchee, courtesy Melody Hunt, Research Gate. The Caloosahtchee was connected to Lake O in the late 1880s by Hamilton Disston after he blew up the waterfall rapids at Lake Hipochee and dredged on to the Lake.

EyeonLakeO, Todd Thurlow: http://eyeonlakeo.com