Army Corps sending C-44 Canal water east into St. Lucie River, west into Lake Okeechobee
TCPalm interviews Mark Perry and covers that the Army Corps of Engineers is getting ready for expected heavy rain this weekend by releasing water from the swollen C-44 Canal east into the St. Lucie River and west into Lake Okeechobee.
The Army Corps of Engineers is getting ready for expected heavy rain this weekend by releasing water from the swollen C-44 Canal east into the St. Lucie River and west into Lake Okeechobee.
If the releases continue for a couple of weeks or more, they could cause environmental damage — more likely to the St. Lucie River estuary than to Lake O.
The canal stretches from the Port Mayaca Lock and Dam on Lake O in western Martin County to the St. Lucie Lock and Dam on the St. Lucie River southwest of Stuart. It's the conduit for Lake O discharges that have brought toxic algae blooms to the river in recent summers.
Lake O's elevation Tuesday morning was 11 feet 7 1/2 inches, well below the average of 13 feet 9 inches for July 30. So lake discharges into the river are unlikely anytime soon.
The water pouring through the St. Lucie Lock and Dam — more than 1.6 billion gallons from Saturday through Monday — is all rainfall runoff from land on both sides of the canal. None of it is from Lake Okeechobee.
In fact, when the Corps opened one of the gates at Port Mayaca on Tuesday morning, water started "back flowing" west from the canal into the lake.
That's because the canal water elevation is nearly 3 feet higher than the lake elevation.
Drop 6 inches
The Corps' goal for the releases east and west is to bring the canal level down about 6 inches to 14 feet, said spokeswoman Erica Skolte.
That would be about 151.5 million gallons off the 25-mile-long, 300-feet-wide canal, provided no more water comes in.
But water is coming into the canal from recent rains, and a lot more is expected.
Some areas around the canal and Lake O could get up to 4 inches of rain by the end of the weekend, said David Sharp, a meteorologist at the National Weather Service in Melbourne.
"This time of year we get a moist marine flow that keeps the area somewhat awash," Sharp said. "Plus we've got some tropical waves that, although they may not develop into tropical storms, will bring in more moisture."
How strong, how long
Whether the releases cause any environmental damage depends on how much water is sent east and for how long, said Mark Perry, executive director of the Florida Oceanographic Society in Stuart.
"If it's a small amount over a week or two, we should be OK," Perry said. "If they're high volumes over a longer period, there will be concerns about low salinities in the estuary that could harm oysters and sea grasses."
Salinity and water clarity in the St. Lucie River estuary are in the "good" and "fair" range, according to the most recent water quality report card from the Florida Oceanographic Society in Stuart.
The society gave the estuary an overall B-minus grade, toward the lower level of the "good" range, as of July 25.
The extra water isn't expected to cause blue-green algae blooms in the estuary, Perry said. Widespread blooms occur only when algae is released from the lake; and remember, water is actually flowing into the lake, not coming out if it.
The "back flow" will add nutrients from west Martin County fertilizer runoff that could feed algae blooms in the lake, Perry admitted.
But the 730-square-mile lake would be better able to accommodate the extra water than the 12-square-mile estuary, he added.