Sand Bypass, Dredging and Beach Re-nourishment
Inlets are man made or natural cuts between the ocean and inland waterways. Normally, inlets interrupt the natural flow of sand, often creating erosion on ‘downdrift’ beaches. Florida’s 1988 Beach Management Act requires inlet authorities or appropriate coastal zone management entities to replace the net amount of sand they interrupt or trap.
Sand bypass, dredging and beach renourishment projects must be accomplished under carefully monitored and controlled conditions. They also must be carried out during specific time frames that protect various endangered species and or other environmental factors. Periodic dredging of sand trapped inside the inlet and placement on the two to three mile stretch of beach south of the inlet takes place every 3 – 5 years.
The primary project goal is to provide protection to the barrier island shoreline of the Sebastian Inlet State Park between FDEP Monuments R-3 and R-12 (9,000 ft. of shoreline) and to mitigate the historical adverse effects of the Sebastian Inlet on the downdrift oceanfront properties. The secondary goal of the project is to provide storm protection for the upland property, infrastructure, and hurricane evacuation routes connected to the project area. The third goal of the project is to provide direct recreational enhancement to the nourished beaches and subsequent enhancement to the downdrift beaches.
The SID worked with IRC to conduct a renourishment of the Ambersand Beach, south of the inlet in 2006 – 2007. Approximately 85,000 cubic yards of sand was dredged from the inlet sand trap and hydraulically pumped to the beach before sea turtle nesting season began May 1st, 2007. An additional 158,000 cubic yards was placed on the beach by the County in 2007-2008 from an offshore sand source to make up for the beach loss during the 2004 hurricanes. Dredging of the Districts Sand Trap was completed May 1, 2007.
In 2010 the District partnered with Indian River County to renourish the beaches south of the inlet. The District’s fill template immediately south of the inlet was healthy, not requiring more sand. Due to the state mandate of beach renourishment, the District is obligated to place sand on the beach to maintain its annual beach fill quota. The Indian River County project placed 267,182 cubic yards of sand from upland sand mines starting approximately 5 miles south of the inlet to north of John’s Island. The upland sand source was significantly less expensive than previous offshore dredging costs by nearly $10 per cubic yard which helped stimulate the local economy by using local sand mines. The District contributed $4,184,070.12 to the project and gained 3 years of sand credit in Phase I of the project.
In 2012 the District dredged its Sand Trap, extracting 122,000 cubic yards of beach quality sand, placing it on the beach south of the inlet between R-4 – R-9.