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Makowski, C.; Finkl, C.W., and Vollmer, H.M., 2016. Classification of continental shelves in terms of geospatially integrated physiographic realms and morphodynamic zones. The continental shelf off southeast Florida contains a range of benthic environments that are discernible via remote sensing platforms because of low turbidity in the water column. Using the Geospatially Integrated Seafloor Classification Scheme (G-ISCS), physiographic realms and associated morphodynamic zones were cognitively interpreted and classified at a nominal scale of 1:6000 across four remote sensing platforms ( i.e. GeoEye IKONOS-2, Landsat-5 Thematic Mapper [TM], Landsat-7 Enhanced Thematic Mapper [ETM], and National Agriculture Imagery Program [NAIP] high-resolution aerial orthoimagery). Attribute tables were created in conjunction with interpretations to quantify and compare spatial relationships between classificatory units and the different remote sensing platforms. Resultant maps exported from ESRI ArcGIS® ArcMap software showed that while IKONOS-2 satellite imagery and NAIP aerial orthoimagery provided the greatest detail, classification of physiographic realms and morphodynamic zones was still possible using TM and ETM satellite images. Overall, it was determined that IKONOS-2 provided the most beneficial imagery when applying such a classification of coastal and seafloor features. It is postulated that accurate delineation of physiographic realms and morphodynamic zones can provide a foundation for more in-depth biogeomorpholocial classification ( e.g., further subdivision into benthic geoforms, coastal landforms, biological cover) along continental shelves. [ABSTRACT FROM AUTHOR]

Abstract: Ocean currents contain a remarkable amount of kinetic energy and have potential worldwide capability. Initial tests to harness current power focus on the Straits of Florida where the Florida Current has a total flow capacity of about 30×106 m3 s−1. Generation of clean electricity from ocean currents off southeast Florida is based on a power extractor comprising open-center turbine technology. This innovative turbine provides safe passage for fish and other aquatic species. The water-column array of energy production units (EPUs) will have a 350km2 footprint, based on a 600m (10 rotor diameters) downstream separation distance between EPUs with a lateral separation of 400m. Water depths for the EPU field are in the range of 100–500m. With such a large area of water column and benthic habitat utilized, environmental concerns must be overcome, including routing of transmission lines to shore. Risks and vulnerabilities of the proposed ocean current generated electricity include failure of individual EPUs and damage to sensitive coastal marine environments during installation. [Copyright &y& Elsevier]

Continental shelf environments along the Florida Atlantic southeast coast offshore Palm Beach County were mapped by interpreting seafloor topography derived from airborne laser bathymetry. The study area covered approximately 270 km² along 75 km of coast, extending from the shore to about 55 m water depth beyond the shelf break to the upper Florida-Hatteras Slope. Forty-two mapping units were used to depict seafloor features that ranged from bedrock outcrops and coral reefs to different types of morphosedimentary bodies. Background theory and protocols of geomorphological symbolization are provided as a rationale for the seafloor mapping. Geomorphological mapping symbols were developed specifically for this project and collected in a symbol library as part of an ArcInfo GIS extension that was used to produce the maps in a GIS environment. Spatial distribution patterns of landform assemblages evident in the color-pattern mapping units permitted regionalization of shelf environments into three primary geomorphological reaches: Reach I, Sand Flats and Karst Topography; Reach II, Sand Flats and Coral Reefs; and Reach III, Sand Flats, Hardgrounds, and Coral Reefs. The main hardbottom mapping units include rock outcrop and subcrop, rock rubble, ridge fields, and structural sand flats. Sandy nontidal morphosedimentary bodies include diabathic channel fields, dune fields, sand flats, and bar and trough systems. Tidal morphosedimentary features include ebb-tidal deltas, sandbars, and lobe bars. Results of this mapping effort showed that it is possible to map marine and drowned terrestrial landforms on the continental shelf as depicted in high-resolution airborne laser bathymetry. Adaptation of existing symbols or development of specialized symbolization was required to show geomorphic units to advantage. These maps, which characterize shelf environments, are contextualized in terms of shapes, forms, materials, and coastal process zones. These types of maps find immediate application in regional and detailed sand searches for beach renourishment, subsea cable and pipeline routes, wave and current modeling studies, and environmental management. [ABSTRACT FROM AUTHOR]

The article presents an illustrated reference of biophysical environment of Florida's St. Vincent Island, Gulf of Mexico coast. Topics discussed include coastal belt linked classification (CBLC), related environments and habitats; dominant catenary sequence (DCS): coastal ecological sequence (CES); and related geology, biology, geomorphology, littoral oceanography.

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]

Differentiation of continental shelf morphology along the southeast Florida Atlantic coast was based on interpretation of airborne laser bathymetry. The 600-km2 shelf study area, which had a shoreline extent of about 160 km and extended up to 10 km offshore, displayed a diverse range of seafloor morphologies that were characteristic of four main alongshore reaches. Reach I (sand flats and karst topography) in the northern part of the study area is terminated southward by the Bahamas Fracture Zone, a major morphotectonic feature. Reach II (sand flats and coral reefs) is characterized by sand flats with diabathic channel fields leeward or shoreward of the Florida Reef Tract, the seaward margin of which occurs along the shelf break on the upper part of the continental slope. Reach III (sand flats, hardgrounds, and coral reefs) is characterized by extensive nearshore rock outcrops that are exposed as bare rock surfaces on the seafloor or are variously mantled by thin veneers of sand that are not thick enough to disguise the underlying rock structure. Reach IV (tidal sand flats and ridges, hardgrounds, and coral reefs) is dominated by tidal features that notably include fields of tidal sand ridges in the lee of the Florida Reef Tract. The barrier reef on the southeast Florida Atlantic coast, which transitions to Florida Keys shelf environments southward, grades northward to drowned karst topography that is overlain by sand sheets and sand waves. Tidal channels and associated bars, deltas, and shoals occur on the interface between Biscayne Bay and the Atlantic Ocean. This reconnaissance-level characterization of continental shelf environments into morphological reaches in a geographic information system platform provides a basis for quantifying spatial distribution patterns of discrete landform units. [ABSTRACT FROM AUTHOR]

Much of the coastal southeast Florida Peninsula is heavily urbanized, and many native environments have been destroyed or severely affected by urbanization. In an attempt to reconstruct potential natural environments, soil properties were used as a basis for recognizing prior landscapes. Pedological associations were adopted because they provided landscape features that were least modified by urbanization and they could be used as a unifying basis for categorization of native coastal environments. A geographic information system analysis ring was used for querying coverages for soil distribution patterns, vegetation, hydrology (drainage), topography, and geology. By simultaneously generalizing and recombining soil survey data, land use cover types, topography, and hydrology, it was possible to identify recurring patterns of soils, landforms, and vegetation. Results of this analysis produced 13 land systems with 25 subunits that included various types of lakebeds, tree islands, marshes, prairies, sloughs, sandplains, glades, marshlands, lagoons, estuaries, and beaches. The resulting map for potential natural environments in Palm Beach and Broward Counties complements conceptual ecological models for the Greater Florida Everglades Ecosystem, developed for the Comprehensive Everglades Restoration Plan. The Australian land systems approach, as applied in this study, provides insight into coastal environments that lie outside of ecological models for mostly protected areas inland. [ABSTRACT FROM AUTHOR]

Beach nourishment requires large volumes of sand from offshore and new sources are constantly sought for development. The sediment-starved continental shelf off the central-west coast of Florida has traditionally supplied beach-quality sediments from ebb-tidal shoals and nearshore sand sheets, but as these supplies dwindle, sand searches increasingly look farther offshore for resources. Widely spaced sediment ridges, interspersed by karstified limestone seafloor (hard grounds), offer potential as sand resources that can be exploited by dredging to renourish eroded beaches for shore protection. The sand ridges, late Holocene in age, are generally shoreface detached, sediment starved, and clustered in "ridge fields." Six sediment ridge fields identified along 285 km of coast (Anclote, Sand Key, Sarasota, Manasota, Captiva, and Collier) contain about 1.4 billion cubic meters of sediments that are potentially available for dredging. Evaluation of these sediment sources, within the purview of the USMinval Code, requires the determination of resources, reserves, and level of certainty of assessment applied to a rating of resource potential. Present research is attempting to identify the overall resource potential with an eye toward eventually determining sand volumes in reserves, which will be much less than the total sand resource volume. [ABSTRACT FROM AUTHOR]

Airborne laser bathymetric (ALB) systems rapidly acquire large, high-quality datasets via variable swath widths that are independent of water depth. Laser bathymetric survey tools have applicability in dear coastal (Case II) waters down to -70 meters depth. Deployed along the southeast Florida (Palm Beach, Broward. and Miami-Dade Counties) coast, an advanced ALB system provided a continuous dataset for 160 kilometers of coast from onshore to 6 kilometers offshore. Digital terrain models developed from this high-density bathymetric data permitted recognition of numerous seafloor features and bathymetric patterns from different image formats. Bathymetric analysis of the 600-km² survey area on the narrow continental shelf shows inherited lithulogic features that are partly covered by surficial sediments. Primary parabathic provinces include: (1) nearshore rocky zones dominated by the Anastasia Formation. (2) coral-algal reef systems (Florida Reef Tract [FRT]), and (3) marine terraces. Secondary sedimentary subprovinces include shoreface sands, inter-reefal sedimentary infills (coral rubble in basal sequences and near reef gaps), and finer-grained materials seaward of the FRT. Tertiary topographic features include: (1) longshore bar and trough systems, shoals, sand sheets, and diabathic channels; (2) reef crests and ledges, forereef spurs and grooves, sediment ramps in large reef gaps, and incised paleo-river channels; and (3) drowned karst topography. Hierarchical organization of these bathymetric features is now possible for the first time because of the increased accuracy and density of bathymetric data obtained by ALB systems. [ABSTRACT FROM AUTHOR]

Abstract: Studies of coastal morphodynamics are becoming increasingly more focused on quantification of relationships between processes, form and function of dynamic landform systems because wave climates (e.g., wave height, wave period, seasonality, cyclical patterns) and sediments (i.e., composition, size, and shape) interact in various ways to collectively produce distinctive types of beaches. This paper identifies criteria and boundary conditions that characterize beaches in terms of morphodynamic states (environmental conditions or energetic stages of development) that produce discrete beach types. Long-term hindcast wave statistics (U.S. Army Corps of Engineers, Wave Information Study), small-scale aerial photography, cross-shore beach profiles, and beach sediment data from Florida''s Atlantic (Delray Beach) and Gulf (Longboat Key) coasts were used as a basis for linking beach morphology with coastal processes. The role of cross-shore sediment variation in classification of beaches is related to prediction of beach types using the dimensionless fall velocity (Ω), the results of which are compared with field observations and morphological interpretation of aerial photographs. A new curve-fitted equation, the morphodynamic boundary condition (MBC), identifies parametric limits that force dissipative or reflective beach conditions when new sediments are artificially placed on the beach (e.g., during beach nourishment programs). Results indicate that the Ω parameter of the new model is strongly influenced by cross-shore selective sorting of bimodal sediments, temporal changes in beach grain size, seasonal wave patterns, and inputs of new sediments to the littoral system. Calculation of Ω using beachface samples produces a bias toward reflective states (decrease in Ω). Sediment samples from bar systems, on the other hand, produce a bias toward dissipative states (increase in Ω). Composite grain size of the active profile is recommended because it more accurately predicts beach states based on Ω (compared to field observation of beach type). The addition of new sediment to beaches requires an understanding of form–process continuums and the MBC equation is a step in that direction. The potential impacts of beach nourishment on beach morphology can be thus determined from local wave data by calculating hypothetical Ω values as a function of changes in beach composite grain size and a constant K value. The MBC equation (Ω=Kdf−2), as applied in planning phases of renourishment projects, can predict changes in beach morphodynamic states, as conditioned by the grain size of the placed fill. [Copyright &y& Elsevier]

The subtropical Atlantic coastal zone of southeastern Florida supports nearly 7 million inhabitants on a coastal plain conurbation that stretches from West Palm Beach to Miami. About a quarter of the present population originally settled on higher topography along the shore-parallel Atlantic Coastal Ridge. From about the middle 1900s, however, urbanization intensified along the shore and spread westward into freshwater marshlands. Population densities approaching 2500 persons per km[sup -2] along some coastal sectors and dredge and fill operations to create urban land in western marshes degraded coastal environments bringing in question sustainability. Efforts to maintain environmental integrity initially focused on shore protection first via "hard" engineering works, which later ont included massive beach renourishment projects along developed coasts subject to critical erosion. Marine algal blooms, led to eutrophication, degraded coastal water quality, and deterioration of coral reefs indicate environmental problems at least as serious as beach erosion. Recognition of a potential eco-catastrophe, collapse of entire marine and coastal wetland ecosystems in southern Florida, led turn to the Everglades Restoration Project, the largest single environmental recovery effort in the world. Cleanup of terrestrial systems is essential to sustainability of marine ecosystems now jeopardized by nutrient loading. Serious degradation of the Florida Reef Tract, a coral-algal barrier reef system, is beyond question as extensive sectors of coral reef die from increased loading of nearshore waters by elevated nitrogen (N) and phosphorus (P) nutrient levels delivered to the coast by submarine groundwater discharge (SGD). The source of N-P input into the Biscayne Aquifer, which has one of the highest carbonate aquifer transmissivities in the world, is sugar cane farming in the Everglades Agricultural Area on the inner portion of the coastal plain. Groundwater discharges for Palm Beach County are, for example, estimated from a groundwater MODFLOW model at 1,659 X 10[sup 6] m³ yr[sup -1]. Total N in groundwater below the coastal plain adjacent to remnant Everglades averages about 1.25 mg l[sup -1]. SGD nutrient fluxes to the coast are 5727 and 414 metric tons per year for P and N, respectively. Surface water contributions for P and N are respectively 197 and 2,471 metric tons per year. Nutrient delivery to beach and nearshore environments is a serious problem that threatens coastal water quality which in turn will impact tourism-related activities such as sunbathing, beach walking, swimming, snorkeling, SCUBA diving, and surf fishing. The full magnitude of the problem has yet to surface because it takes about three to eight decades for groundwater from the interior parts of the coastal plain to reach the nearshore zone. Pollution of groundwater increases with time due to higher doses of fertilizers on croplands and runoff from expanding urban areas. Solutions to present environmental threats are obvious and, perhaps surprisingly, do not fall within the scientific arena because causes and remedies are already known and future impacts are anticipated. The present environmental cleanup efforts, which are of mammoth proportions and financial cost, are doomed to failure until the causes of problems are eliminated or neutralized. Even though sustainable management procedures are well known, sustainability cannot be achieved by treating symptoms. Sustainable coastal habitats in subtropical southeast Florida will be secured when there is application of best management practices based on environmental ethics rather than capital gain, development of political will directed towards continuous multiple land use rather than terminal single use, and inculcation of proactive public perception of best land management practices rather than politically-correct land-use policies. [ABSTRACT FROM AUTHOR]

ABSTRACTCoastal plains in southeast Florida are prone to flooding by storm surges and extreme rainfalls. In the example of southeast Florida, coastal flood studies are based on well-defined evacuation zones that are mapped according to hurricane intensity. The areal extent of flooding, due to high-rainfall storm events, on developed wetlands and “flood-proofed” coastal plains is difficult to assess using conventional techniques because the landscape is being rapidly modified by urban development. New techniques deployed in the emergency management preparedness process include spatiotemporal analysis of satellite imagery in conjunction with geographic, land, and marine information systems. Land uses within flood hazard zones are classified from satellite images in an effort to quantify the impacts of storm surges for successively higher flood levels associated with hurricane Categories 1, 3, and 5 evacuation scenarios. The geomatics involved shows that ∼10% of the total flood zone is in urban/residential land use but accounts for most of the damage to personal property and infrastructure. Potential flood zones on interior coastal plains were mapped from GIS soil coverages by identifying locations of hydric soils, poor drainage conditions, surface water hydroperiods, and associated hydrogeomorphic features. These advanced procedures helped establish a new protocol for coastal flood-hazard mapping in Broward County, Florida. [ABSTRACT FROM AUTHOR]