TARPON SPRINGS — After the appearance of a 50-foot-deep sinkhole, S Disston Avenue and nearby Dorsett Park will remain closed because boring samples and ground-penetrating radar revealed "anomalies" underground that must be repaired or further studied.
The city called in a geotechnical engineering firm, Tierra Inc. of Tampa, last week after a sinkhole opened up in the street in front of 709 S Disston Ave. on June 16. Tierra also was asked to examine depressions in the soil at Dorsett Park that were noticed the following day.
The city filled in the Disston Avenue sinkhole, using 25 dump-truck-loads of sand. However, the street can't be reopened to traffic because of what Tierra found when it examined the area.
The company drilled in a 150- by 90-foot area, probing more than 50 feet below the roadway surface. The tests found several indicators that limestone below the ground had collapsed.
Sinkholes in Florida often are caused when limestone lying deep underground collapses and the soil above it funnels downward, leaving a crater on the surface.
Before the road will be safe for travel, the ground will need to be injected with a special grout that will increase the density of the soil and make it more resistant to collapse, Tierra wrote in a report to the city. Tierra estimates the work will cost roughly $35,000.
"We anticipate that the roadway will be closed for approximately one more week until these remediation efforts are complete and have been thoroughly inspected," Tarpon Springs spokeswoman Judy Staley said Friday.
The city doesn't know when popular Dorsett Park, about a block away from the Disston Avenue sinkhole, will reopen. A preliminary examination of the park by Tierra showed "subsurface anomalies," not just beneath the visible depressions there, but also in other parts of the park where there are no depressions.
Drilling and other tests will be done next week to get a better idea of what's happening beneath the surface at Dorsett Park, Staley said. In addition to several depressions, the city found cracks in the park's tennis court. The park is now off-limits to visitors.
Another property also was affected by the sinkhole activity on June 16. Several sinkholes opened in the yard of 709 S Disston Ave., where Nathaniel Crawford, 90, and his wife, Virginia, 83, had lived since 1957. The Crawfords and several relatives fled the house as the ground opened up.
The city has advised the Crawfords not to move back into their house yet.
The Crawfords had sinkhole insurance and are waiting for information from their insurance company about the cost and feasibility of repairs.
Diane Steinle can be reached at firstname.lastname@example.org or (727) 445-4184.