Sarasota County staff details observations on barrier islands
Altogether, Sarasota County’s beaches fared “relatively well following Tropical Storm Elsa,” staff has announced.
A July 8 report on assessments of shoreline conditions noted, especially, that the recently renourished area of Manasota Key Beach seemed to have handled the storm’s effects without any problems, though the document did caution that staff was awaiting further information from the project managers.
The renourishment initiative was completed in April 2020.
In general, the report continued, “Isolated and limited erosion impacts at several areas known to be affected during past tropical storm events was observed. No structural damage was observed … on Manasota Key and Casey Key, including no observed damage to dune walkover structures, fences, privacy walls, or cabanas.”
The report did point out that some of the “‘at risk’ gulf-front homes on Manasota Key in the 7100 block experienced effects of wave action” and loss of the oversize sand bags called TrapBags, “but no structural damage or undermining of foundations was observed.”
“We have not received any calls reporting structural damage or requesting Class I Emergency Variances for sandbagging at this time,” the document noted.
“Additionally,” the report said, “some areas on Manasota Key and Casey Key experienced accretion/deposition of sand onto the upper beach areas, as evidenced by some sea turtle nest stakes being partially buried. Some sea turtle nest washout occurred, as exposed eggs were observed on Manasota Key” in a couple of places.
Countywide, the report noted, “Elsa was predominantly a rainmaker, dropping 2 to 8 inches or more … with localized flooding experienced in some areas.”
When staff members were undertaking their assessments on July 7, the report said, they did find areas of road flooding on Siesta and Manasota keys.
The report emphasized that the assessments were “based on visual inspections, local knowledge of our beaches, and comparisons of the photo-documentation of pre-storm and post-storm conditions. No specific surveying or topographic measurements are taken during these initial post-storm beach and dune assessments. Therefore,” the document continued, “the evaluation presented here is qualitative rather than quantitative and should not be used to make conclusions on estimated volumes of sand lost or gained in our coastal areas. In addition,” it pointed out, “wind and strong wave action was observed during the July 7, 2021 Beach Assessment, which may have resulted in further changes to our coastline after staff reviewed the pre-selected stations.”
The remainder of the report is divided into segments relating to each barrier island.
The portion of the beach at 9230 Blind Pass Road “continues to experience erosional forces following the latest South Siesta Key Renourishment Project in 2017,” the report said. “Wave action was reaching the seawall around the swimming pool at the time of the Beach Assessment inspection,” it added.
That pool was full of sand, the report noted, and erosion was observed on the landward side of the seawall, exposing some of the tiebacks. However, the report said that those observations might not be directly linked to Elsa.
On Beach Road, the report continued, flooding was observed at the intersection of Columbus Boulevard. The report explained, “This area has been observed in the past as [one] that typically experiences flooding.”
On North Casey Key Road, where step revetments exist, wave overwash and minor sand deposition on the roadway occurred, the report noted. “The road remains stable and passable.”
The report added, “Strong wave action was observed colliding with the step revetments at both locations, but no overspray was observed reaching the road” during the inspection.
The report also pointed out, “The County is actively developing plans and pursuing permits for repairs and maintenance of the northern step revetment area in the vicinity of 728 North Casey Key Road.”
In the area of 2110 to 2100 Casey Key Road, the report noted that the county-installed sandbags “south of the bend in Casey Key Road performed well and remained intact.” Staff also is working on a “more permanent structure” to stabilize that part of the shoreline, the report pointed out.
At 2020 Casey Key Road, “[p]reviously approved [TrapBags] performed well at this location and remain intact and functional.” The area landward of the TrapBags, where dune vegetation was planted, “appears to be doing well and was not impacted by the storm,” the report said.
At 2007 Casey Key Road, the report noted, the property owner received a Class II Emergency Variance earlier this year for construction of a temporary seawall and additional foundation underpinnings. In place since June, the report continued, the seawall and underpinnings “have provided protection to the foundation of the residential structure. This site experienced accretion of sand as well, as evidenced by before and after images …”
At Blind Pass Beach Park, dune vegetation planted along Manasota Key Road “persisted following the storm,” the report noted.
Flooding on the road was observed on July 7 at three locations, it continued, with “some rather deeper floodwaters [estimated at 8 to 10 inches] over the roadway” between 6415 and 6260 Manasota Key Road.
At 7110 Manasota Key Road, the report added, recent efforts to restore the dune with beach-compatible sand proved successful during Elsa’s passage along the coast. Staff did observe wave action “reaching the base of the dune walkover staircase,” the report noted, but no significant damage was seen in regard to the stairs, deck or residential structure.
Conversely, at 7160 Manasota Key Road, the report said the TrapBag system installed at that location was mostly destroyed. “Only a few functional sandbags remain near the southern property line,” the report explained. However, sand recently placed in that area, including beneath the deck, remained there, the report added.
At 7180 Manasota Key Road, wave action appeared to have reached the base of the bluff line, which resulted in exposure of foundation underpinnings approved in 2020 through a Class II Emergency Variance, the report pointed out. On the other hand, the report said, the upper part of the beach at that site “appears to have gained some elevation.”
Finally, at 7210 Manasota Key Road, for which a Class II Emergency Variance also was approved in 2020, so foundational underpinnings could be installed, those underpinnings were found to continue to be supporting the foundation. Further, sand recently placed along that portion of the shoreline “remained in good condition.”