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The Florida Everglades, the largest subtropical wetland in North America, is in the midst of one of the most comprehensive and expensive environmental restoration efforts in history. Over the past 150 years, the Everglades has suffered substantial degradation due to massive drainage projects, polluting agricultural practices, and urban population growth. Decades of scientific investigation have shown that phosphorus (P) pollution is a primary driver of this environmental decline. This paper reviews how and why specific P‐management goals and strategies have been adopted in support of Everglades restoration, focusing on the often‐contentious process for converting science into restoration policies and standards. We synthesize current P‐management successes, failures, and tradeoffs, including the challenge of balancing multiple hydrologic and water quality restoration goals with the priorities and values of a diverse group of stakeholders. We then highlight promising future directions for Everglades P policy and propose questions to help guide the discussion of future restoration priorities and research needs in this and other complex social–ecological systems. The overall goals of this review are thus twofold: (1) to support an in‐depth understanding of the past, present, and potential future of P management approaches in this globally unique social–ecological system; and (2) to provide a broader framework for understanding how the coevolution of science and policy can support or undermine large‐scale ecosystem restoration. [ABSTRACT FROM AUTHOR]

Managed treatment wetlands technology is now used around the world to treat wastewater and stormwater by removing nutrients and other contaminants to obtain a desired water quality. In this paper we present a brief review of a large-scale application of the nature-based technology known as stormwater treatment areas (STAs). These STAs were constructed to treat agricultural and urban runoff to reduce outflow total phosphorus (TP) concentrations to <20 μg P L−1, which is required to protect downstream water quality and preserve the remaining Everglades ecosystem. Five STAs with a total area of approximately 25,000 ha were built at strategic locations to reduce TP loads to the Everglades Protection Area. For the past three decades, these Everglades STAs have done remarkable job by 70 to 85% TP load reduction, with an average outflow TP concentrations of 15-40 μg P L−1. In this Everglades STAs special issue, we present research findings on the influence of both external and internal drivers influencing STA performance and potential adaptive management strategies to enhance treatment efficiency to further reduce outflow TP concentrations. • Introduction of the Everglades STAs – largest constructed treatment wetland network in the world. • Everglades STAs serve as 'kidneys' of the Everglades ecosystem by reducing phosphorus loads to downstream waterbodies. • Phosphorus loading is one of the key drivers regulating treatment efficiency STAs. [ABSTRACT FROM AUTHOR]

Traditional economic forecasts had consistently underestimated the hypergrowth of South Florida and its need for freshwater from the 1970s through the 1990s. It was hypothesized that the continued rapid growth of urban and farm water use into the 2000–2030 period would undermine efforts to restore the Everglades. To test this hypothesis, the corresponding author had hybridized two widely used regional economic modeling tools: the static, single-period Impact Analysis for Planning (IMPLAN); and the dynamic multiperiod Regional Economic Modeling Inc. (REMI) to forecast population and water use for the period from 2010–2030. In the present paper, these early forecasts are compared to actual census and water use counts for 2010 and 2015. Some of these early forecasts are found to be surprisingly accurate while others seriously overshoot the mark. The on-target forecasts validate the basic hybrid model while the other "deviant" forecasts measure the success of the radical antidrought policies and the region's economic reaction to the financial collapse. This retrospective provides a new metric for measuring actual changes in the paradigm of water consumption. [ABSTRACT FROM AUTHOR]

The Everglades is a complex, multiwetland ecosystem that is heavily managed to meet often-competing flood control, water supply, and environmental demands. Using objective measures to balance these demands through operational protocols has always been a challenge in the multibillion-dollar restoration plans for the ecosystem. Physically based models have been the primary tools for planning efforts but for such a complex system, they are laborious and computationally intensive. Development of optimal operations based on iterative runs of these models is a great challenge. This paper presents an inverse modeling framework for formal optimization suited for wetland system operations that helps overcome such limitations. Labor-intensive and computation-intensive physically representative models are emulated in each individual wetland area using an autoregressive artificial neural network with exogenous variables. Using prescribed inflow, outflow, and meteorological input data, such hydrologic model emulators aided by a dimension-reduction technique provide targeted spatial and temporal predictions for water level (stage) within each area of the Everglades, while excluding computation processes that are intensive but insignificant to the predictions. This computer software uses the augmented Lagrangian genetic algorithm technique (subject to linear and nonlinear constraints) to steer predictions of stage spatial variability within individual wetlands towards corresponding desired goals (including restoration targets). In the augmented Lagrangian genetic algorithm, flow releases are coded as the decision variables to be optimized subject to budget, intrahydraulic conveyance, flow capacity, and upstream storage constraints. Optimization is performed by dividing and solving a sequence of subproblems using the genetic algorithm procedures of initialization, selection, elitism, crossover, and mutation. As part of the process, Lagrangian and penalty parameters are updated, and optimization terminates when certain stopping criteria are met. Applying the technique reported in this paper to a specific Everglades restoration plan (the River of Grass Project) showed a sound hydrologic model emulator prediction when compared to the physical model for all wetland areas. Feeding optimal releases predicted by the computer software into a physical model showed equal or better matching of the restoration target with different release patterns compared to that of the physical model base run scenario. Results show that hydraulic conveyance limitations play a significant role in Everglades restoration. Also, results show that employing an adversity tradeoff matrix presented multiple so-called optimal solutions with different optimization weights and a powerful negotiation matrix. [ABSTRACT FROM AUTHOR]

Eutrophication is a widespread global scale pollution problem. Agricultural areas are generally the main contributors to eutrophication, whereas sewage and industrial discharges, which usually receive some treatment prior to discharge, are a secondary source. This is mostly the case of the ultra-oligotrophic Florida Everglades, where natural water sources are often enriched by nutrients from large-scale industrial agricultural stormwater runoff. Remediation of these agricultural waters cannot be conducted with the usual environmental engineering solutions, and in this context ecological engineering approaches such as constructed wetlands are much more suitable. Moreover, these wetlands provide other ecosystem services such as carbon sequestration or habitat provisioning. In this paper we have implemented a mechanistic phosphorus model into a time-space-dependent mathematical simulation platform (COMSOL Multiphysics™) which has been calibrated with wetland mesocosm data. Subsequently we have evaluated different characteristics of constructed wetland physical elements such as internal walls and baffles, different types of inlets, parallel and series operation, and increase in hydraulic retention time (HRT) to study total phosphorus (TP) removal performance and to improve efficiency. Simulation results indicate that wetland mesocosm soils released dissolved organic phosphorus which was washed out together with the effluent, making very difficult to attain a concentration lower than a target of 10 μg TP L−1, as required to protect the Everglades. Simulations showed that the design based on combination of the bottom inlet together with parallel operation extensively improves efficiency. Target TP concentrations can be achieved with this design together with an increase on 25% of hydraulic retention time. With this study we demonstrate the usefulness of the model for detailed designs, opening the door for its use in field scale applications. Image 1 • Pollution caused by agricultural drainage waters is a worldwide problem. • Constructed wetlands are very suitable to prevent agricultural drainage pollution. • A complex model was developed to study phosphorus removal. • The model is very useful for detailed designs and field scale applications. [ABSTRACT FROM AUTHOR]