County’s Public Utilities staff still working on additional water supply expected to be needed by 2030

More water could be obtained from Peace River Authority, but County Commission would have to make formal request seven years in advance

Reprising what they reported early this year, Sarasota County Public Utilities Department staff members have informed the County Commission that the county will need additional water supplies by 2030 “to meet future demands.”

Working from the basis of 20-year projections, a county staff memo says, county staff will need to start adding extra water sources gradually, beginning in 2025, to meet the anticipated, increased demand of 5 million gallons per day (mgd) in 2043, the memo adds.

The information was provided in the agenda packet for the commission’s regular meeting on Dec. 13. Each year, the memo explains, the county is required to provide the Peace River Manasota Regional Water Supply Authority projections of the water supply demand for the next 20 years. The county gets most of its potable water supply from the Authority.

On Dec. 13, the commissioners unanimously approved the report that the Public Utilities staff had included with the memo. That action came in the form of their vote on their Consent Agenda of routine business matters. Although a board member can pull an item from that agenda for discussion, no one mentioned the water demand issue prior to the Dec. 13 vote.

During a regular session in early January of this year, the board members signed off on the previous report for the Peace River Authority.

The Dec. 13 staff memo explains that the county has a water supply contract in place with Manatee County, as well as the Peace River Authority. However, that Manatee County agreement will expire in April 2025, resulting in the loss of 5 million gallons of drinking water per day.

The memo points out that the county’s University Wellfield and Treatment Facility, near University Parkway, has 2 mgd of permitted capacity, but it “depends on the Manatee County water supply for blending purposes to meet water quality requirements. As such,” the memo continues, the University facility “is anticipated to be out of service by 2025.”

Staff previously considered installing a reverse osmosis operation at that facility, the memo notes, but “it has been determined that this is not a cost-effective source of water supply …”

Instead, the memo explains, staff’s “preferred option” is a transfer of the groundwater allocation from the University facility to the county’s Carlton Wellfield and Treatment Facility, which is “just north and east” of Interstate 75, a 2005 county document notes. It stands within the T. Mabry Carlton Jr. Memorial Reserve near Venice. In May, the memo points out, staff received a permit from the Southwest Florida Water Management District (SWFWMD) to make that reallocation possible.

The transfer of the groundwater flows, the memo says, has been “planned to occur in conjunction with the expiration of the Manatee County contract.”

Nonetheless, the memo points out, while the Carlton facility will provide the extra water supply “for the immediate future,” the Peace River Authority also could provide more water to the county in coming years. “Public Utilities continues to have discussions with the Authority” in regard to water supply options, the memo adds.

The Authority provides the county “an average supply of up to 15.06 MGD,” the memo notes. If the County Commission wishes to increase that level, the memo says, it must make such a request “at least seven years prior to the date of service.”

Last year, the memo points out, the county requested an extra 1.5 mgd from the Authority starting in 2028. “This year’s demand projection has Sarasota County requesting an additional allocation of 2.5 MGD, beginning in the year 2029, from the Authority,” the memo continues.

Further, the memo points out that staff still is planning to retire the Venice Gardens Wellfield and Treatment Plant by 2030. That is necessary, the memo explains, because of multiple factors, including the diminished yields from the wellfield, aging equipment and increased operating costs. “The supply from this facility,” the memo says, represents 2.75 mgd of permitted capacity, which will decline in the years leading up to the retirement date.

Additionally, the memo points out that staff is continuing to rehabilitate the Carlton Wellfield and Treatment Facility, which is “part of the overall strategy to meet future demands.” Construction of the second phase of that work is expected to be completed in March 2023, the memo adds. Then, the capacity of the Carlton plant will rise from 12 mgd to 15 mgd, the memo says.

A chart included in the Dec. 13 agenda packet shows that the annual average daily flow (AADF) of water demanded by county customers this year is 25.26 mgd. By 2030, the chart says, the AADF is expected to be 27.34 mgd. Then, by 2044, the anticipated figure is 30.98 mgd.

The same chart shows that the available capacity this year is 38.084 mgd. That is expected to decline to 37.584 mgd in 2030 but then rise to 40.584 mgd by 2035 and remain at that level through 2044.

For comparison purposes, The Sarasota News Leader reviewed the county’s water projection chart for a December 2020 presentation to the County Commission. That showed the estimated AADF for this year was 24.5 mgd. In 2018, the chart noted, the actual AADF was 19.74 mgd.

That chart also showed the projected AADF for 2030 was 26.58 mgd.

For 2042 — the last year in that chart — the figure was put at 29.7 mgd.

The Dec. 13 chart for the commissioners projected the 2042 AADF to be 30.46 mgd.