Project History

The beaches of Duval County, along Florida’s “First Coast”, enjoy a long and rich history that has been heavily influenced by coastal construction.  There are about 16 miles of ocean beaches in Duval County, divided by the St. Johns River Entrance (Figure A).  The six miles of beach north of the river are part of a large expanse of public parks and remain mostly undeveloped.  In contrast, the ten miles of beach south of the river are mostly developed and urban in nature.  These include the 1.0- and 1.5-mile shorelines of the Mayport Naval Station and City of Jacksonville’s Hanna Park, closest to the river entrance, and 7.5-miles of urban shoreline referred to collectively as “The Beaches”.

 

From north to south, this includes the Cities of Atlantic Beach, Neptune Beach, and Jacksonville Beach.  These three local governments maintain separate budgets and governance but each share common services with the City of Jacksonville via an intra-local agreement.  For more than 100 years, the beach cities have been an important and heavily utilized recreational amenity for the citizens of Duval County (Figure B).

The Duval County coastline has been profoundly changed by navigation improvements built at the St. Johns River Entrance.   These include construction of two rock jetties by the U.S. Army Corps of Engineers beginning in 1879 which were subsequently sand-tightened in the early twentieth century (Figure C).  The length of the north and south jetties is about 3 miles and 2.5 miles, respectively.  As a result of sand impounded against the north jetty, the natural inlets north of the River Entrance have shifted north and one has nearly closed, and new islands have formed and overlapped old ocean shorelines.  On the other hand, the jetties — combined with persistently deeper channel dredging and the resulting changes to the ebb tidal shoal — act as a littoral barrier that deprive the southern beaches of their natural sediment supply and have caused The Beaches to erode.  This erosion, probably combined with imprudent development upon the natural dunes in the early 1900’s, prompted coastal residents and businesses to construct timber bulkheads as early as the 1910’s and 1920’s during the Florida land-boom.  After storms in 1925 and 1932, most of these bulkheads were replaced by concrete seawalls (Figure D).

Widespread coastal armoring combined with a chronic sediment deficit resulted in a gradual deflation and narrowing of the beach profiles throughout southern Duval County, from the 1920’s through the 60’s and 70’s (Figure E).  The nor’easter of 1962 — followed by the passage of Hurricane Dora in 1964 — extensively damaged the beaches and coastal communities (Figure F).  The Corps began placement of sand dredged from the River Entrance to the 1-mile shoreline of Mayport Naval Station, just south of the inlet, in 1963.  But the coastal damage was severe enough to warrant congressional authorization of the Federal Shore Protection Project along the entire southern 10 miles of the Duval shoreline, south of the St. Johns River Entrance.

The authorized beach nourishment project consists of a 60-foot wide construction berm at an elevation of +11 ft, MLW.  The original 1965 authorization included federal fiscal participation for 10 years, which was later extended to 50 years.  The current federal projection authorization has been recently extended to 2040.  In 2023, dune restoration was adopted into the scope of the federal project (instead of being the sole responsibility of the City of Jacksonville).

 

The Corps’ authorizing design document was adopted in 1975.  Initial project construction placed about 3.7 million cubic yards (cy) of sand on the beaches between 1978 and 1980, including sand from maintenance dredging.  Since then, there have been five principal renourishment events along portions of the southern, urban shoreline (in 1985-87, 1991, 1995, 2005, 2011, 2016/17, and 2018/19) along with periodic placement of maintenance dredged sand along the northern project shorelines of Mayport Naval Station and Hanna Park, just south of the inlet (about every 3 to 5 years).  The dunes were gradually rebuilt in the 1990’s through sand fencing and vegetation.  The dunes were mostly re-constructed in 2016/17 after erosion from Hurricane Matthew, and fully re-constructed in 2018/19 after Hurricane Irma — including planting of 960,000 sea oats by the City of Jacksonville in 2017-2018.  The upcoming 2024 renourishment will repair beach and dune erosion from Hurricanes Ian & Nicole (fall 2022) with 1.3 million cubic yards of sand and planting of 506,000 sea oats and other native dune plants.   The total volume of sand placed along the 10-mile project area from 1978 through 2023 is about 14 million cubic yards, of which about 37% is from navigation dredging at the River Entrance and 63% is from an offshore borrow source about 8 miles seaward of the project area.

This equates to about 300,000 cubic yards per year – which compares well with the 1975 pre-project prediction of 260,000 cy/yr – especially when it is recognized that much of this placement volume includes maintenance-dredged sand that is placed beyond the requirements of the shore protection project. These efforts combined with a dune fencing & vegetation program, and post-storm renourishment by the City of Jacksonville have resulted in a remarkable transformation and restoration of Duval’s beaches.

Figures G through I visually compare beach conditions in Atlantic Beach and Jacksonville Beach in the early 1970’s prior to project construction with those observed in 2010 and 2011.  Project performance both visually and technically is outstanding.

The 2024 project will restore the beach and the dune to its pre-storm condition prior to Hurricanes Ian & Nicole (2022). Because the project is being built during marine turtle nesting season, the entire shorefront will be monitored daily to relocate marine turtle nests out of pending work areas, or marked for avoidance where work is already completed, by Beaches Sea Turtle Patrol & Hanna Park. Two 2000-ft long ‘gaps’ in the 2024 beach nourishment are specified for the relocation of marine turtle nests — one at the southern end of Jax Beach and one in central Hanna Park – where no construction will occur. The amount of sand that would otherwise renourish these two areas will be placed adjacent to the ‘gaps’; and that sand will subsequently drift into the ‘gap’ areas by natural wave processes, so that the entire project shorefront is ultimately renourished.

The construction cost of each beach nourishment project is typically split between the US Army Corps of Engineers (61.6%), the City of Jacksonville (20.4%), and the State of Florida (18.0%).  However, the construction cost of the 2024 project — about $34 million — is paid 100% by the federal government (Corps of Engineers) because it qualifies for repairing storm erosion damage from Hurricanes Ian & Nicole.  Likewise, the local (City of Jacksonville) expenditures for the prior 2016/17 and 2018/19 renourishments — after Hurricanes Matthew & Irma — were over 90% reimbursed by federal and state grants obtained by the City of Jacksonville.  The City otherwise pays for annual surveys, beach tilling, and project planning requirements between renourishment events, which is mostly cost-shared with the State of Florida. Eligibility for federal and state cost-share is significantly determined by public beach access and parking along the project shoreline.

With more than three decades of successful periodic renourishment, the Duval SPP is one of the three oldest federal beach nourishment projects in the state.  A natural byproduct of highly successful long-term beach projects can be waning of public awareness regarding the original (and continued) need for beach nourishment.  In Duval County, for example, one might be hard pressed to find an average beachgoer who is aware that the remnants of a rip-rap armored seawall are directly buried by the restored dune system.  With continued renourishment of the Federal Project hopefully a history lesson is the only education they’ll receive on the subject.

Photo Credit — Many of the photographs included in this article are from the Beaches Area Historical Society, Jacksonville Beach, FL.