Bonita Beach Summary & Conclusions

• During the period of project construction a net increase of 263,030 cy of sand was measured within the project limits.  Analysis of the immediate pre- and post-construction beach profiles indicated that 217,300 cy of sand were placed during construction.  The remaining 45,700 cy of accretion occurred naturally or as a result of impoundment due to groin construction which preceded fill placement by several months.
• The "project area" has approximately 73% of the placed beachfill remaining within the monitored area of Little Hickory Island through September 1998.
• The MHWL within the original project fill limits experienced recession of an average of 13 feet during the second year monitoring period and 48 feet from December 1995 to September 1997.  During the third year monitoring period the average MHWL recession was only 8 feet.  The average berm width for the remaining beach fill as measured from the pre-project berm to the September 1998 berm location was 47 feet.  Similarly, in September 1998, the average MHWL beach width for the project area was 76 feet.  The project area shoreline did not change substantially during the third year monitoring period.
• For 1998, the profiles shifted less than 5 feet in either direction and remained stable with an average of 0.1 feet of recession.  This stability suggests that any southerly dispersion of sand observed during the first and second year monitoring period has essentially ceased.
• The average rate of shoreline recession from 1989 to 1995 was approximately 9 feet/year (pre-construction) for southern Lover's Key.  The average rate for southern Lover's Key was higher (approx. 17 feet/year) during the second year (1996-1997) following construction of the restoration project.   During the third year (1997-1998) following construction, the average erosion rate decreased to 9 feet/year.   The latter includes the effects of Hurricane Georges.  The shoreline change rate for 1997 to 1998 has therefore returned to the pre-project rate measured between 1989 and 1995.
• Overall, Big Hickory Island experienced significantly lower rates of recession for the third year monitoring period when compared to the second year monitoring period.  The exception to this trend was shoreline recession of 32 feet/year found at R-223.  Big Hickory Island experienced accretion at a rate of 20 feet/year from September 1996 to September 1997.

• This project placed about 145,000 cy of sand along approximately 3,900 feet of shoreline.
• The project area gained about 114,700 cubic yards of material in the active beach profile based on pre- and post-construction monitoring surveys, while the adjacent areas lost an average of approximately 10,700 cubic yards in the active beach profile; however, there is a bias in the survey data.
• The terminal groins are functioning to hold the placed material in the project area.