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Lake Okeechobee is Florida's largest lake, the largest lake in the Southeast United States, and the second largest lake contained entirely within the United States. The history of this inland sea is marked both by natural processes, and more recently human development and intervention. Adventurers can explore this behemoth of a waterway via the Lake Okeechobee Scenic Trail that enriches it, a part of the Florida National Scenic Trail. This paper synthesizes major natural and human-induced perturbations that shaped the lake and ultimately the trail that encircles it to create a narrative of Florida's great lake. The story of Lake Okeechobee is a story of battles, first between the land and sea, then between the lake itself and humankind. For the past few centuries Lake Okeechobee's natural perturbations in water flow and flooding resisted the control of man, until recently when man triumphed, managing to control the flow of water in and out of the lake. Unfortunately, with this new found control a new bioecological threat in the form of harmful algal blooms has emerged, which again threatens the health and livelihood of South Floridians. Currently there are new efforts that seek to restore Lake Okeechobee towards a more natural state in an effort to thwart the blooms. [ABSTRACT FROM AUTHOR]

Asian swamp eels (Monopterus albus/javanensis) were first reported as introduced to Florida waterbodies in 1997 near Tampa and Miami; a third population was recorded by 1999 in Homestead. Initial assessments, published soon after swamp eels in southern Florida were first recorded in wetlands beyond canals and ponds (in 2007), concluded there was little threat to Florida’s aquatic ecosystems. Long-term data now suggest they precipitated population crashes of crayfishes and small fishes in the eastern Everglades. We used records from continuous long-term monitoring programs, sporadic monitoring studies, and online databases to reconstruct swamp eel presence across Florida. Monitoring studies provided wetland hydrologic variables to assess limits for swamp eels. From 1997–2007, populations in southern Florida remained restricted to canals; initial spread from 2007–2017 across southern Everglades National Park proceeded slowly and the two populations covered ~1500 km² of southern Florida. From 2017–2022, the rate of spread increased as they spread west and north (~5800 km² range). Through 2014, the Tampa population occurred only along southern/eastern Tampa Bay (~60 km²) but has since spread south along the Gulf Coast, east into central Florida, and south along the Lake Wales Ridge (~11,000 km²). We found evidence of two potentially new introductions, in Palm Beach County and Orlando. There was no clear evidence of limitation of wetland drying on swamp eel occurrence in the Everglades; they were captured in marshes that dried for 1–5 months during the previous dry season, but short-hydroperiod wetlands may have slowed spread. In the Everglades, evidence suggests swamp eels may have been inadvertently spread into marshes from canals used to deliver water for flood control and hydrologic restoration. Swamp eels are currently spreading unchecked across Florida, and there should be great concern about continued spread in this region and their establishment and spread elsewhere. [ABSTRACT FROM AUTHOR]

[Display omitted] • The trends of surface runoff and flood area changes were different. • Rainfall change is the dominant driver compared with land use change. • There are coupled effects from rainfall and land use changes on both surface runoff and flood area. • The easily flooded areas would experience negative coupled effects under future rainfall and land use conditions. • The areas with inadequate drainage and low elevation variation would be of high probability to suffer flooding issues. Future rainfall and land use are two important factors for flood management since they both directly and indirectly affect the functionality and performance of urban stormwater drainage infrastructures. Although some studies have already examined the coupled effects of future rainfall and land use conditions, they have not concluded how such effects on both surface runoff and flood areas would change with regional surface elevation variation and infrastructure conditions. This paper analyzed the coupled effects of future rainfall and land use on urban drainage systems in terms of surface runoff quantity and flood area changes using EPA SWMM. Future downscaled and bias-corrected precipitation projections for 2040–2060 and 2080–2099 from "Downscaled CMIP3 and CMIP5 Climate and Hydrology Projections" Archive and future land use for 2050 s and 2090 s from EPA ICLUS project were used for the City of Tampa in Florida (USA). It was shown that potential runoff volume and flood area changes ranged from −40% to 160%, and −40% to 400% due to rainfall change, while potential changes induced by land use change ranged from 0% to 3.5%, and 0% to 18% respectively. Additionally, this study examined the coupled effects of future rainfall and land use changes on flood area variations, considering the capacity of drainage infrastructure and elevation variation of study site. Results showed that flood area variations are not solely influenced by runoff quantity changes due to the two external drivers, but also by other factors. Specifically, in low-relief areas with inadequate drainage infrastructure and less elevation variation, these two drivers have no additive effects on the percentage of flood area changes. In contrast, in areas with adequate drainage infrastructure and greater surface elevation variation, there are additive effects from rainfall and land use changes on flood area expansions. These findings have important implications for stakeholders involved in city planning and flooding control, particularly for urban areas facing future precipitation and urbanization challenges. [ABSTRACT FROM AUTHOR]

Water control operations in South Florida often involve the estimation of transition flow at low-head gated spillways for flood control, water supply, and water quality compliance purposes. Approaches to nontransitional flow computation have been extensively investigated, and their accuracy and applicability have been rigorously verified. However, computational algorithms for transitional flows have not generally been accepted by engineering practitioners; arguments even exist with regard to the criteria used to delineate different transitional flow regions. In this study, a generalized discharge rating equation for spillways is proposed that, in contrast to the classical flow-type-separation approaches, can estimate both transitional and nontransitional flow rates. Several verification tests were performed, including a consistency analysis of the proposed equation compared to classical flow equations for different flow conditions and its verification with field and laboratory data. The performance of the proposed equation in transitional flow regions was further evaluated using computational fluid dynamics (CFD) simulations. The discharge estimates agree well with measurements and classical rating equations, with overall computation absolute relative errors of less than 8%. Finally, the inherent limitations of traditional spillway flow-type-separation approaches were analyzed, and the analysis suggested that the generalized equation is a better alternative to overcome the hard-to-define transition thresholds and resolve the discharge discontinuity issue. [ABSTRACT FROM AUTHOR]

Miami-Dade County (south-east Florida) is among the most vulnerable regions to sea level rise in the United States, due to a variety of natural and human factors. The co-occurrence of multiple, often statistically dependent flooding drivers – termed compound events – typically exacerbates impacts compared with their isolated occurrence. Ignoring dependencies between the drivers will potentially lead to underestimation of flood risk and under-design of flood defence structures. In Miami-Dade County water control structures were designed assuming full dependence between rainfall and Ocean-side Water Level (O-sWL), a conservative assumption inducing large safety factors. Here, an analysis of the dependence between the principal flooding drivers over a range of lags at three locations across the county is carried out. A two-dimensional analysis of rainfall and O-sWL showed that the magnitude of the conservative assumption in the original design is highly sensitive to the regional sea level rise projection considered. Finally, the vine copula and Heffernan and Tawn (2004) models are shown to outperform five standard higher-dimensional copulas in capturing the dependence between the principal drivers of compound flooding: rainfall, O-sWL, and groundwater level. The work represents a first step towards the development of a new framework capable of capturing dependencies between different flood drivers that could potentially be incorporated into future Flood Protection Level of Service (FPLOS) assessments for coastal water control structures. [ABSTRACT FROM AUTHOR]