Sand Key Summary & Conclusions

• The total calculated volume loss of sand in the nourished segment (from R-99G to R-107) between July 88 and January 90 surveys is 86,696 cubic yards, which is a loss about 16.3 percent of 529,150 cubic yards actually placed in the nourishment project.  The total loss of sand computed in the entire survey area is 22,348 cubic yards, which is only 4.2 percent of the sand placed in the nourishment project.   It is stressed that a part of these net volume reductions is due to the background erosion and not due to spreading losses induced by the nourishment project.

• Volume changes to the depth of closure show that 7.4% of the sand placed on the beach was lost from the nourished area after two years.  7.2% of the nourishment volume was lost after one year.  This shows that the rate of volume loss was greatly reduced during the second year of the project.  Within the monitored area, there was a net gain in beach volume of 4.2% after two years.  The volume increase is primarily due to the Indian Shores renourishment project, which overlapped the four southernmost monitored profiles. The relatively small amount of sand lost by the renourished profiles between December 1991 and December 1992 (0.2% of the renourishment material) is partly caused by volume gains associated with end-loss from the Indian Shores project.
• The Indian Rocks Beach renourishment project is performing well after two years.  Relatively rapid loss of shoreline in the first year of monitoring was greatly reduced in the second year.  In the second year of monitoring, longshore transport of sand from the foreshore became increasingly more important because the profiles had adjusted to the local wave climate and exhibited a more natural shape.

• Post-construction profiles indicate there was a wider berm crest along Clearwater and Belleair beaches of approximately 200 feet as compared to the 135 foot authorized width.  This increased width is due to the contractor only being able to place the sand at a 1 on 5 slope rather than the specified 1 on 20.
• The shoreline along Belleair Shores has been experiencing accretion and shoreline advance due to end losses from Clearwater, Belleair, and Indian Rocks Beaches located to the north and south moving sand into the community.
• The profile for R-66 shows a depression in the offshore area that is approximately 2,400 feet from the monument.  A booster station was placed in the vicinity of R-66, and this depression may be due to scour around the legs of the station, and the water intake for the booster.
• The southern portion of Sand Key, north of the John Pass Inlet through to the south end of the project has remained relatively stable to slightly accretional and is likely due to impoundment of sand from a series of groins in the R-120's region that have been rehabilitated recently.
• High end losses have been observed at the northern and southern end of Indian Rocks Beach and North Redington Beach respectively.  These losses may require a structural solution to extend the performance of the project and maintain project performance at these locations.