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Cutler, E.M.; Albert, M.R., and White, K.D., 2019. A low-cost shoreline dynamic simulation model for proposed beach nourishment and dune construction: Introducing a new feasibility analysis tool. Journal of Coastal Research, 35(4), 907–919. Coconut Creek (Florida), ISSN 0749-0208. Beach nourishment and dune construction are common coastal risk-management strategies for shoreline erosion in the United States. Federal involvement with such projects relies on cost–benefit analyses, which in turn rely on life-cycle models of shoreline processes, such as the Army Corps of Engineers' Beach-fx event-driven physical and economic coastal model. However, use of these models can be computationally and data intensive. Costs associated with conducting a feasibility analysis for beach nourishment and dune construction may leave a community with few resources to explore other risk-management options. This paper, therefore, presents a first-order, screening-level, low-cost dynamic model that delivers results approximately comparable with those from life-cycle models. Applying the model to three locations in Florida shows that simulated nourishment intervals are within 5 years of those predicted by Beach-fx, leading to a similar number of nourishments over a 50-year project life span. A discussion on how one could apply the model to other areas is also included. It is intended that this model could serve as a first-pass screening tool for communities considering beach nourishment and dune construction before they decide to invest in the more thorough, but costly and data-intensive, life-cycle model simulations. [ABSTRACT FROM AUTHOR]

This paper describes a methodology for modeling long-term evolution of multiple inlet systems in southwest and central Florida. The paper discusses the application of this methodology to two inlets within Sarasota Bay system in southwest Florida. The case studies of Longboat Pass and Venice Inlet demonstrate the importance of considering large temporal and spatial scales in multiple inlet systems. The results describe the evolution of Longboat Pass and Venice Inlet from 1880 to present. The analysis begins with natural conditions that existed before dredging or inlet modifications and investigates how inlet evolution can be influenced by navigation improvements or mining of ebb shoals for beach nourishment. [ABSTRACT FROM AUTHOR]

Huang, W.; Hagen, S., and Bacopoulos, P., 2014. Hydrodynamic modeling of Hurricane Dennis impact on estuarine salinity variation in Apalachicola Bay. Hurricane Dennis made landfall in Florida on 10 July 2005 and caused a storm surge of 2.4 m in Apalachicola. Field observations of salinity, winds, and river inflows are available at a few stations in the bay during the hurricane event. Presented in this paper is a numerical modeling study that investigates the effects of Hurricane Dennis on estuarine mixing and transport. A previously calibrated three-dimensional (3D) estuarine hydrodynamic model was further validated by the field observations of salinity and water levels during the hurricane event. A large-scale storm-surge model was used to provide storm-surge hydrographs at the five estuarine boundaries for the 3D estuarine model. This model integration proved successful with the results indicating that the model predictions of storm-surge hydrographs and salinity match well with observations. Model predictions of spatial distributions of salinity and current fields are presented to demonstrate the fresh-saline water mixing at different times of the storm-surge event. Results indicate that the hurricane-induced storm surge caused substantial increase of salinity in the bay. Majority saline water entered the bay from the east during the storm surge event. Salinity at the oyster reef, Cat Point in the eastern bay area, is more sensitive to the increased water levels caused by storm surge than another oyster reef, Dry Bar, in the western bay area. [ABSTRACT FROM AUTHOR]

South Florida, United States, is an ideal place for conveniently studying modern carbonate environments and their fossil equivalents in close proximity. It is the only place where such field studies can be carried out with the excellent logistical support available in a major metropolitan area (Miami). Consequently, south Florida has been used extensively for training petroleum geologists as well as providing reef and quarry trips of short duration for geology classes. However, south Florida can also be used to study geomorphic features; biogenic and clastic sedimentology in fresh, brackish, and saline environments; and stratigraphie studies which correlate widely-spaced rock outcrops. In addition, many aspects of environmental geology, including groundwater, water pollution, ecological changes accompanying development, and the effects of hurricanes, can be studied here. This holistic approach was used in a 3 week laboratory and field course first offered in the summer of 1985. The area has been visited several times since then, and the places and features described in this paper are accurate as of February 2012. A uniformitarian approach was used, in which students studied rock outcrops and then examined the present-day depositional equivalent of each facies by snorkeling over modern reef tracts in the Florida Keys. Outcrops of Pleistocene rock units were examined from Miami southward through the Florida Keys. Students utilized the outcrop data, along with published data and their own observations of reef complexes, to make a regional stratigraphie synthesis and paleogeographic reconstruction for the study area. This article describes the course structure, field exercises, and logistics, which can serve as the basis for similar courses or site visits in this area in the future. Additional information is provided so instructors can tailor the course around their available time and financial limitations, anywhere from 3 days to 3 weeks. [ABSTRACT FROM AUTHOR]

At present, little is known about the mechanisms that control water level variations for the Frog Creek system, west-central Florida, which is a mangrove-covered, microtidal, shallow estuary. Although connected with open waters, topographic and roughness constraints can alter expected variability of water levels in this area. Water level variations are especially important for the Frog Creek system, because the increases or decreases in subtidal water level change the present tidal environments. In this paper, 1-year measurements of water levels were examined using the empirical orthogonal function (EOF) method. Water level data from eight stations were first filtered by employing a Lancz6-squared filter because of its ability to eliminate diurnal tidal signals while inducing minimal attenuation in variations with periods of 2 to 3 days, which are usually caused by wind. The filtered water levels were then analyzed using the EOF method to determine relative contributions of various forcing factors. The first three EOF modes explained 64.13%, 33.25%, and 1.55% of total variances and were interpreted by calculating correlation coefficients and coherences. We attributed EOF mode 1 to the variations of coastal subtidal water levels introduced by physical processes with longer periods, such as spring-neap tidal variability and seasonal freshwater river discharge variability. Next, EOF mode 2 was related to the effects of the local N-S wind component, which introduces short-timescale variations of the subtidal water level with typical periods ranging from 2 to 6 days. The effect of river discharge on water level was captured by EOF mode 3. Overall, EOF analysis provides an insightful tool to examine water level disturbances. [ABSTRACT FROM AUTHOR]

This paper introduces the recently developed resource "Characteristics of the Shoreline Change along the Sandy Beaches of the State of Florida: An Atlas" (available on the web). The shoreline positions on which the Atlas is based encompass 2F coastal counties extending over 1162 km of shoreline and averages over almost 140 years. The data were analyzed over three different periods (early, recent, and total) to distinguish mainly beach nourishment and sand bypassing projects, primarily in the recent period. The east and west coastlines of Florida have advanced significantly in the recent period relative to the early period, with the recent and early period average shoreline change rates being +23 cm/y and +18 cm/y on the east coast and +27 cm/y and -7 cm/y on the west coast, respectively. This improvement is attributable to, in part the large quantities of sand placed during nourishment and sand bypass projects. Shoreline changes in the vicinity of the inlets were examined, and it was found that shoreline fluctuations decreased significantly with increasing distance from the inlets, and that sand bypass and nourishment projects reduced the shoreline variability during the recent period. [ABSTRACT FROM AUTHOR]

Santa Rosa Island, situated along the northwestern Florida coast facing the Gulf of Mexico, is an 85-km-long wavedominated low-lying barrier island with well-developed incipient and established dunes. In this paper, we examine the regional-scale effect on coastal dunes by a strong category 3 hurricane, Ivan, through comparison of pre- and poststorm airborne LIDAR (light detecting and ranging) surveys. On the basis of pre-Ivan LIDAR survey data, the elevation of the berm and back beach is typically 2.0 m above MSL (mean sea level). Incipient dunes range from 2.5 to 10 m above MSL, or 0.5 to 8.0 m above the surrounding beach. The hummocky dunes that developed over relic washover platforms are typically less than 4.0 m above MSL. The densely vegetated, established dune fields are composed of dunes less than 7.0 m high and intradune wetlands lying at less than 1.0 m above MSL. The entire island was severely affected by Ivan, which made landfall about 45 km to the west in September 2004. The landscape was substant lly changed by Ivan. Over 70% of the incipient and hummocky dunes were destroyed, and a large portion of the low-lying wetlands was covered by washover. The degree of storm-induced morphology change depends not only on the intensity and duration of the storm but also on the antecedent morphological characteristics of the barrier island. Comparison of pre- and post-Ivan cross-island LIDAR profiles indicates that at most locations, more sand was eroded from the subaerial portion of the barrier island (e.g., beach and dune) than was deposited as washover terraces and lobes. This suggests a net sand loss to the offshore region. Evidence of sand moving alongshore related to the oblique orientation of the dunes was also identified. Under inundation regime, the subaerial sediment deficit could be accounted for by subaqueous sedimentation into the back-barrier bay. [ABSTRACT FROM AUTHOR]

Since 1973, Delray Beach, located on the southeast coast of Florida, USA, has been periodically nourished. The morphological evolution of these nourishments has been influenced by design aspects (e.g, changes in shoreline orientation), extreme events (hurricanes, northeastern storms), and dredging of offshore borrow areas created to provide the nourishment sediments. This paper describes a thorough analysis of the physical processes influencing nourishment performance using the process-based model Delft3D. The analysis distinguishes three steps: (1) a wave analysis, (2) a hydrodynamic analysis, and (3) a morphological analysis. The wave analysis shows that the oldest, deeper, borrow pits (dredged in 1973 and 1978) have the largest effect on the nearshore wave climate, while the effects of the reefs can be considered negligible. Results from the hydrodynamic analysis indicate that differences in wave height cause variations in alongshore current velocities related to differences in wave setup and local wave angle. The morphologic analysis also shows a large influence of the older borrows on fill performance. Bar formation behind the borrows is predicted by the model; however, this feature couldn't be confirmed with 300-m spaced beach profile data. Higher current velocities were predicted in the shadow zone behind borrow areas because of gradients in wave-induced water levels and changes in wave direction induced by the borrows. The higher than average erosion in the southern end of the fill appears to be caused by changes in shoreline orientation and to a lesser degree, borrow area effects. Modeling played a key role in understanding the observed morphological development of the fill. The use of different bathymetric scenarios proved to be a useful method in isolating the physical processes relevant to nourishment performance and assessing their relative effects. [ABSTRACT FROM AUTHOR]

Storm overwash is a critical issue in coastal management efforts to mitigate damage to infrastructure. This paper contributes to those efforts by documenting the findings of a field survey at the Perdido Key, Florida, section of Gulf Islands National Seashore following the landfall of tropical cyclone Isidore in September 2002. The poststorm survey of overwash sites detected scouring along the northern edge of an access road that faced away from the Gulf of Mexico and the oncoming storm surge. Most sites experienced removal of minor amounts of sand and roadbed material, which left the edge of the overlying asphalt road surface unsupported. However, more severe scouring at one site caused the overlying asphalt road surface to fracture and collapse. An extreme example of this process was observed following the landfall of Hurricane Opal at Pensacola Beach, Florida, in 1995. The scouring process and its effects were consistent with a process recognized in fluvial systems as knickpoint development. Related scouring processes known as hydraulic jump and dam overtopping are also discussed. Coastal management options for mitigating this problem include reducing overwash and increasing resistance to scour. Methods to protect dams from overtopping offer potential solutions to this problem. An alternative solution is proposed that would offer protection against minor overwash events; however, it is unlikely that any of the methods discussed herein would be highly effective against an extreme event like Hurricane Opal. [ABSTRACT FROM AUTHOR]

Accuracy of predicting storm surge inundation depends on the model grid resolution. The spatial resolutions of many storm surge models are on the order of hundreds of meters to kilometers, which are not sufficient to resolve irregular shorelines and small topographic features. In this paper, storm surge and inundation simulation for Hurricane Andrew of 1992 was carried out with the unstructured tidal, residual, intertidal mudflat (UnTRIM) hydrodynamic model. A high-resolution unstructured grid with cell sizes as small as 20 m was placed over the Key Biscayne Bay area near Miami to better represent irregular shorelines and small morphological features such as barrier islands, rivers, canals, and inlets. A series of experiments was conducted to test model performance with respect to model grid resolution, time step selection, open boundary condition specification, and tidal influence. Results show that the model simulated maximum surge heights and areas of inundation along the Biscayne Bay coast very well, indicating that the UnTRIM model is useful in simulating storm surge flooding. [ABSTRACT FROM AUTHOR]