The city of Statesboro is purchasing an almost $285,000 solar-powered, automated rainfall monitoring and water release system for Lake Sal, a roughly 14-acre lake in the northwestern part of town, as part of larger planned flood control project for the neighborhood.

Owned by the Lake Sal Homeowners Association, the lake is within the loop formed by Northlake Drive and Zetterower Road. A Bulloch County Board of Tax Assessors map shows the area held by the HOA measuring 15.0 acres, with a boundary conforming closely to the extent of the water’s surface on most sides but including a strip of land along the north bank with a leg extending toward Northlake Drive on the west.

“Especially here lately with all the big rains we are getting, the lake fills to capacity and it starts flooding into the neighborhoods near the entrance, going into some of the yards, and I think that we’ve had some houses flooded out too,” said Assistant Public Works Director by Marcos Trejo. “So we’re trying to create flood storage within the lake, so the lake will receive all of the water instead of it pushing back into the neighborhoods.”

Also the city’s stormwater manager, he was interviewed briefly after Tuesday’s council vote.

Years in consideration

In fact, flood control measures for Lake Sal and the Northlake area have been in discussion and study phases for several years, from recognition of problems well before the 2024 storms.  Back on Oct. 4, 2022, the council approved “Task Order 6” as a specific addition to a 2016 stormwater master-planning services agreement with  the architecture and engineering firm Goodwyn Mills Cawood, or GMC.  For $49,840, GMC was to do a survey of Lake Sal and its overflow structure, update a hydrologic model of the lake’s drainage basin and help  the city prepare a design solution.

Even before that time, GMC had looked at the area and proposed construction of a stormwater detention basin near Myrtle Crossing and Zetterower Road. But city “staff encountered property acquisition challenges” with that proposal, according to a fall 2022 memo.

Then at the end of January 2023, city staff members and a “project team” including representatives of both GMC and OptiRTC Inc., a company that specializes in digitally adapted stormwater control, met with people from the Lake Sal Homeowners Association.

That February, the city obtained a permission letter from the HOA for lake access, and the team performed a bathymetric survey – meaning a mapping of the depth of the lake bottom, throughout. These steps are summarized on the city’s website at www.statesboroga.gov/departments/public-works/stormwater-utility/stormwater-projects/lake-sal

This week’s vote

What City Council approved, by  a 4-0 vote at its May 6, 2025, morning meeting was a sole-source purchase agreement with OptiRTC for “stormwater flood control hardware” and also a one-year software subscription and one year of management services at a total cost of $284,836. Specifically, the equipment and software constitute an Opti brand “continuous monitoring and adaptive control,” or CMAC, system, according to a memo prepared by Trejo.

“This contract includes modification of the existing outfall structure to accept the Opti hardware, installing a solar power source, bringing the system on line, training and a year subscription for the … (CMAC) to be installed as part of the Lake Sal project,” he wrote.

The equipment and service order lists the retrofit of the existing outlet assembly to include a remotely actuated valve for automated operation and the installation of water level and rainfall sensors linked to a “cloud-based hub” for data tracking and system management. Cost elements include $153,930 for the hardware and its installation, $25,350 for project management and $49,500 for implementation, plus the $13,200 one-year Opti software subscription and $7,000 for one-year operation and maintenance services.

Those elements and a $35,856 construction contingency added up to the $284,836 total.

According to Trejo, the system won’t be merely reactive, but will be capable of making adjustments in advance of storms.

“It’s connected to the cloud, monitoring weather forecasts, and if the weather forecast calls for a big rain, it will start calculating the probability and will draw down the (lake level by) the rainfall amount in order to receive that stormwater coming in,” he said after the meeting. “We’re trying to raise the capacity for the flood basin by the lake lowering itself. That’s the main idea.”

Larger drainage

A letter from an OptiRTC representative to Trejo, which was included in the City Council packets, states that the system will provide “up to 19.5 acre-feet of adaptive storage ahead of storm events.” It states that this approach has been shown to reduce peak water levels in a pond by 0.9 feet during a 25-year storm event and by 1.4 feet during a 100-year storm.

Although not stated that way in the latter, a 19.5 acre-feet reduction would appear to be a 1.4-foot reduction across about 13.9 acres. The OptiRTC representative stated in the letter that as of 2023, a traditional water detention approach that could provide 1.5 acre-feet of storage had been estimated to cost $700,000 and that the automated system can provide more than 10 times the storage volume at less than half the cost.

According to OptiTRC’s description, Lake Sal drains approximately 600 acres of land, so the area potentially affected by flooding is much larger than the lake itself. The lake discharges through an outlet structure – currently equipped with a manual valve – on the north side of the lake, with the water flowing into Belcher Branch, which continues to Mill Creek, which is ultimately a tributary of the Ogeechee River.

The most recent memo stated that the $284,836 Opti contract cost was below a budgeted amount of $1 million for design and construction, with Special Purpose Local Option Sales Tax funds dating from the 2013 referendum being the source for the Lake Sal Project.

However, the continuous monitoring and adaptive control system is only Phase 1. Further actual infrastructure work, include dredging and installation of culverts and crossings, could cost nearly   $1.2 million, bringing the total project cost to around $1.5 million, Trejo said.