Sanibel Council keeps the door open on Blind Pass
After a long discussion, the Sanibel City Council decided to go with an option recommended by its Humiston & Moore report, which utilizes supplement maintenance dredging of Blind Pass.
Acting Natural Resources Director Holly Milbrandt provided past information regarding Captiva Beach Maintenance Projects and Blind Pass dredging projects, as well as an evaluation of options and costs for future sand placement by the coastal engineering firm Humiston & Moore.
The background dated back to 1988 when FDEP issued a permit for construction of a jetty to the existing Captiva groin on the north side of Blind Pass. With the recognition of potential interruption of littoral sand transport and a cause on the downdrift beach, with the extended groin, the FDEP permit included conditions, which required the Captiva Erosion Prevention District to mitigate any of the downdrift impacts.
In 1994, the City of Sanibel adopted the Sanibel Island-Wide Beach Management Plan, which established a framework for beach management on Sanibel. Erosional hot spots were identified in the plan, which included the northern 1.7 miles of Sanibel, which was designated as critically eroded by FDEP.
An interlocal agreement was established in 2000 for a 15-year period, which CEPD agreed to place sand on north Sanibel as mitigation for erosion caused by the Captiva jetty as part of their periodic Captiva renourishment projects. The agreement expired in 2015 and the next Captiva Island Beach Maintenance Project is currently in the planning phase for 2021-2022.
Acting Director of Natural Resource Holly Milbrandt said the Blind Pass Inlet Management Plan was adopted in 2019 by the state. The goal, she said was to update the inlets sediment budget into developed and improved strategy while addressing the chronic erosion on north Sanibel.
“Lee County is the entity responsible for implementation the plan,” Milbrandt said.
In the past, she said the dredging of the pass has been seeward to the inlet to the point where it impacts the sand bypassing bar that is just off shore of Blind Pass.
“It’s that bar that actually allows sand to pass from Captiva to the bar to north Sanibel,” Milbrandt said. “When past dredging efforts have intruded into that natural sand bypassing bar, that was shown through the modeling, to have an adverse affect both on the inlet, as well as the beaches of north Sanibel.”
In future projects, she said by limiting the extent of channel dredging into that sand bypassing bar, a greater quantity of sand is expected to naturally nourish the critical eroded areas of northern Sanibel beaches.
Another important component of the plan is the required monitoring and performance evaluation. The plan also expanded the permit fill template, which includes the dredged material from Blind Pass to be expanded to include some additional areas.
Both the Captiva Beach Maintenance Nourishment Project and the first Blind Pass Maintenance Dredging Project under the new Inlet Management Plan are in the planning phase and are scheduled to begin implementation in 2021-2022.
With the upcoming projects, the Humistion & Moore Engineers report provided three options for the city to consider for future sand placement on Sanibel. Those include executing a new interlocal agreement with CEPD to partner on upcoming Captiva Beach Maintenance Project; supplement maintenance dredging of Blind Pass with relatively small-scale supplemental sand placement events up to 10,000 cubic yards as need, or do nothing.
“It’s our understanding under a new interlocal agreement with CEPD to partner on upcoming projects, the city would potentially be responsible for the cost associated with placing sand on north Sanibel and the proportional share of the mobilization cost for the Captiva Renourishment Project,” Milbrandt said.
She said based on assumption, if Sanibel was to place 75,000 cubic yards of sand on North Sanibel the estimated construction and engineering cost would be $2.4 million based on the total Captiva project cost of $20 million. The cost to Sanibel would most likely not be less than $1 million.
It was later corrected that it would be $1 million over eight to 10 years, about $100,000 a year.
“It does not appear to be economically justified or really practical from an engineering prospective at this time,” Milbrandt said.
Without any further action, or expense, from the city, north Sanibel is going to benefit from the upcoming Blind Pass Maintenance Dredging. Milbrandt said at this time approximately 84,000 cubic yards of sand is anticipated to be placed on north Sanibel with the 2021-2022 project.
Blind Pass will be dredged on a three to four year cycle.
After the presentation, City Council discussed their concerns with participating in CEPD local governmental funding request for its upcoming project, which has a application due date of Sept. 30.
“There are so many unknowns with the situation,” Mayor Kevin Ruane said. “It’s really going to depend on the cost sharing that we get, so if we are not successful in that sharing, we are committing, hoping, and if we don’t come through its $2.4 (million).”
He said he talked to CEPD Commissioner Mike Mullins that he does believe there are some responsibilities of Captiva. Although the price tag has some urgency, Ruane said they do not have a million dollars lying around doing nothing at the moment.
“It might be an option that later on coming on and amending and at that possibility I didn’t want to close the door completely,” Ruane said. “My thought is certainly not to participate in this plan. Have an open door if at some point that makes sense. Just right now economically, and not necessary the best option they are giving us.”
The council also shared that the right thing to do is be good neighbors, such as offering a staging area at Blind Pass for parking.
Vice Mayor Mick Denham said he believes the principal reason for supplement sand placement on the north end of Sanibel is because of the Captiva decision to put in a groin to protect their beaches. He said he is not willing to say Sanibel should provide funding to fulfill the need to supplement their beaches, which is caused by Captiva.
“I am not too sure why that needs to change,” he said. “The groin is still there. There was an agreement that Captiva, Lee County and CEPD provide the funding to supplement our beaches because of the groin. I still believe that we are called upon to provide city funds to do something that they inherently caused to inhibit the natural cause of sand to our beaches.”
From a practical view point, Denham said to provide a staging area in one of their parking lots he would support.
Council woman Holly Smith said they will always have a door open if something comes up and it works in advantage to their citizens and working with Captiva.
The council decided to go with the second option of the supplement maintenance dredging of Blind Pass with small-scale supplemental sand placement events as needed.
“What I would like to do is keep the door open and since this project is not slated to complete until 21-22, perhaps as nature changes this could go further,” Ruane said. “With that in mind it gives us an opportunity to really look at what we do receive as a result of them doing it.”
He said they should also have a discussion about a new interlocal agreement with Captiva.