Captiva Summary & Conclusions

• Prior to the 1996 fill project, about 1,263,900 cubic yards (79%) of the construction volume placed (in 1988/89) on the beach remained within the Captiva Island area of measurement.  Since the 1988/89 project, Captiva Island had lost about 330,600 cubic yards of fill.
• From April 1989 to the 1996 pre-project survey, Captiva Island lost approximately 277,300 cubic yards of sand.
• The average yearly shoreline retreat rate at Captiva was -3.1 feet during the first 82 months following the 1989 project.  Localized advances were measured near the north end of the island.  The area of highest shoreline retreat was near the center of the island and near Blind Pass.  In the most recent measurement period prior to renourishment, the shoreline retreated an average of -5.9 feet.
• After the first 82 months, the average (+6 foot NGVD) berm width within the project limits was 4.8 feet landward of the 1988 project (design + advance fill) berm width.
• In January through March 1996 the Captiva Island shoreline was renourished with 817,000 cubic yards of sand from an offshore borrow area.  This most recent fill volume was particularly dense in the central and southern portions of the island.

• In the 54 months following the 1996 renourishment of Captiva Island, the Island's MHW shoreline receded an average of 28 feet.  In the same period the beach lost 254,000 cubic yards of sand.  Approximately 69 percent of the 1996 fill volume remains.
• A discernable ebb shoal feature at Blind Pass is no longer present.  A net erosion of 130,000 c.y. has been measured near the former location of the Blind Pass ebb shoal since September 1998.
• As of September 2000, the berm on Captiva Island was on average 6 feet seaward of the equilibrium project width (design fill plus advance fill).  In terms of the remaining berm width, the project has performed as expected or better.
• Based on the volumetric losses from the project areas, the project is performing better than expected.  Approximately 43 percent of the fill placed in 1996 is expected to be remaining in 2004, the planned date for the next renourishment.
• The total erosion of the eroding profiles from Captiva since 1996 is 378,000 cubic yards.

• Captiva Island has receded an average of 35 feet since May 1996 and 8 feet from 2000 to 2002.
• The beach has lost 234,000 cy of fill, which is almost half of the loss since 1996, over the last two years.
• Based on the 2002 survey and the design objective, a plan for the next renourishment of Captiva and Sanibel Islands was developed in April 2002.
• The plan calls for fill along the entire shoreline between Redfish Pass and Blind Pass, and the rehabilitation and extension of the Redfish Pass groin.

• The fill placed by the Corps of Engineers meets the performance standards described in the 1988 and 1996 Design Memorandums and in the 2002 Preliminary Engineering Report.  The Captiva Island project standards are based on maintaining a beach width from the 1987 shoreline.
• In the graph in the PERFORMANCE TABLE section the solid green line is the Corps beach width standard and the dashed green line represents CEPD's desired standard.  At all points on Captiva Island there is a significant advanced nourishment buffer, averaging approximately 100 feet.