How will water move in and out of Lake Okeechobee over the next decade? The image above offers a glimpse of the new Lake Okeechobee System Operating Manual, better known as LOSOM. Allow us to explain.

The arrows pointing to the left of the chart indicate lake flows going west to the Caloosahatchee Estuary. The arrows pointing to the right of the chart are going east to the St. Lucie.

Zone A (above the red line) represents the highest lake stages. Under LOSOM, when the lake level jumps over 17 feet, all bets are off for the northern estuaries. Maximum releases can be sent east and west to protect the integrity of the Herbert Hoover Dike. These high-level discharges are often laced with toxic algae, all but guaranteeing devastating consequences to downstream communities.

In Zone B/C (above the blue line, below the red), discharges may be released to the Caloosahatchee at the S-77 Franklin Lock at a rate up to but not exceeding 7,200 cubic feet per second (cfs). Water may also be released at the S-308 Port Mayaca lock into the St. Lucie, as long as those releases do not cause the S-80 St. Lucie Lock and Dam flow to exceed its target of 3,500 cfs. This zone can be very damaging to the estuaries — though not as damaging as Zone A, when the lake is higher.

Zone D (below the blue line, above the purple line) is where Lake O will spend most of its time. In this zone, the Caloosahatchee can get releases up to 2,000 cfs, while the St. Lucie receives zero.

Throughout the zones, the Corps has great flexibility to determine releases moving out of Lake Okeechobee. This flexibility allows the Corps to take water quality concerns such as the presence of harmful algae blooms into consideration (for the first time ever in a lake operations plan) — but also does not guarantee any particular outcome or prioritization. Meaning, even if there is toxic algae on the lake, there’s nothing to say that they must withhold releases. Ultimately, as the lake creeps higher, so too does the likelihood of discharges.

The vertical arrow throughout the center line of the chart (Green) indicates flows that could be moving south — a good thing — but this is subject to the same vague conditional circumstances that dictate Zone D, as well as available capacity in the system.

Once the lake falls under the water shortage management band (Purple), the Corps defers to the State of Florida, a.k.a. the South Florida Water Management District to determine releases, with the intent of managing the amount of water available in the system as needed for water supply. Herein lies the persistent prioritization of agricultural giants like Big Sugar.

This evening, a series of virtual public hearings will begin, targeting regions north, east, south and west of the lake, to take comments from stakeholders. While we remain certain that LOSOM is an improvement from the current lake management plan, we are mindful that the ambiguous language and the built-in flexibility leaves room for prospective disappointments.

If you do plan to comment at these meetings, we recommend giving the Army Corps feedback that acknowledges LOSOM may allow for decreased harmful discharges to the northern estuaries and increased flows south to the Everglades — but the devil will be in the details. Ask the Army Corps to ensure that these projected benefits become a reality once LOSOM takes effect in 2023.