Watershed Response to Legacy Phosphorus and Best Management Practices in an Impacted Agricultural Watershed in Florida, U.S.A.

Khare, Yogesh; Paudel, Rajendra; Wiederholt, Ruscena; Abiy, Anteneh Z.; Lent, Thomas Van; Davis, Stephen E.; Her, Younggu

doi:10.3390/land10090977

Cited by 12 publications

(6 citation statements)

References 83 publications

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“…In addition, this study assumed that the land covers of the two study wetland watersheds might not change substantially because their wetlands (the dominant land cover) have been highly managed and protected. Legacy phosphorus was known as the major source of phosphorus loaded to Lake Okeechobee (Khare et al, 2021), but the responses of legacy phosphorus transport and loading to rainfall events were assumed to be constant in the future due to the lack of information pertinent to the legacy phosphorus of the study wetland watersheds.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of impacts of climate change on natural and managed wetland basins

Shin

Her

Khare

2023

J American Water Resour Assoc

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Low floodplain wetlands such as the Western Everglades in South Florida are vulnerable to extreme weather events, and their water quality and ecosystem functions vary greatly depending on changes in water levels and discharges. The future (i.e., the mid and late 21st century) climate is projected to result in increased frequency and magnitude of extreme events, which could negatively affect the hydroecological function of the wetlands. Wetland management practices have commonly been implemented to protect wetlands and their functions, but it is not clear whether the current management practices can still be effective in projected climate change scenarios. The main goal of this study was to evaluate the impacts of climate change on the runoff and total phosphorus (TP) of natural (L28 Gap) and managed (L28) wetland watersheds in the Western Everglades. For the assessment, we employed future climate projections made using 29 general circulation models (GCMs) and the Watershed Assessment Model (WAM), a watershed loading model. The WAM was calibrated and validated for the baseline period (2000–2014), and the bias‐corrected climate projections were incorporated into the model to project the runoff discharge and TP loads for the near‐future (2030–2044) and far‐future (2070–2084) periods in two carbon emission scenarios. The modeling results show that the natural wetland watershed would be more vulnerable to projected climate change than the managed wetland watershed. The impact of projected climate change scenarios on daily runoff and TP loads was modulated by water control facilities and practices in the managed watershed, highlighting the significance of watershed management practices for improved water quality under projected climate change. This study demonstrates how the local natural and managed wetland watersheds distinctly respond to the global‐scale changes and emphasizes the role of water management practices in wetland basins, which are expected to help develop effective climate change adaptation plans for improved sustainability of wetland systems.

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Section: Discussionmentioning

confidence: 99%

Evaluation of impacts of climate change on natural and managed wetland basins

Shin

Her

Khare

2023

J American Water Resour Assoc

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“…Explanations for the inadequate BMP responses have centered on legacy P [73,74] and N [75] inputs from the waterbody's watershed stymying management programs [76][77][78]. Soil phosphorus buildup due to past management practices (Legacy P) is often considered a root cause for eutrophication.…”

Section: Sustainability (Eutrophication the Circular Economy Soil Hea...mentioning

confidence: 99%

Put the Land Back on the Land: A National Imperative

E. Canfield Jr,

Kiani,

Tammeorg

et al. 2024

Sediment Transport Research - Further Recent Advances

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The Rivers and Harbors Act of 1899 (RHA1899), the Soil Conservation Act of 1935 (SCA1935), and the Clean Water Act (CWA1972) were pivotal in managing United States (US) waters. RHA1899 provided the Army Corps of Engineers authority to regulate dredge and fill operations. SCA1935 authorized the US Department of Agriculture to combat soil erosion. CWA1972 empowered the US Environmental Protection Agency to regulate point-source pollution. The implementation of the European Soil Charter of 1972 and the 2000 European Water Framework Directive empowered Europe to address similar soil erosion and water quality problems. By 2022, improvements in erosion losses were obtained with soil conservation programs, but continued losses of organic topsoil threatened soil health, human welfare, and water ecosystems. Worldwide losses, estimated at 24 billion tonnes per year, include US and European losses of ~3 billion and 970 million tonnes per year, respectively. Approximately 60% of eroded materials are delivered to rivers and lakes threatening waters. Dredged freshwater sediments, however, have beneficial uses including restoring health of agricultural and forestry lands and water resources. National initiatives involving defense, agriculture, and environmental governmental units are proposed for recycling organic, nutrient-rich aquatic sediments in world-wide Put the Land Back on the Land programs.

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“…Despite these actions, P loading to Lake Okeechobee has instead increased to a current average of 500–600 t/yr, and TP concentrations currently average near 100 ppb (Khare et al 2019). One major challenge of achieving the Lake Okeechobee TMDL is that agricultural and other land uses continue to release P. In addition, P loads from previous decades have become incorporated in Lake Okeechobee's sediments and surrounding agricultural soils (Khare et al 2021). This legacy phosphorus can be resuspended in the water column or leach out of soils, hindering water quality improvement even if current management practices are improved.…”

Section: Phosphorus Management Successes Failures and Tradeoffs (The ...mentioning

confidence: 99%

The past, present, and potential future of phosphorus management in the Florida Everglades

Zacharias

Kaplan

2022

Restoration Ecology

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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.

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Watershed Response to Legacy Phosphorus and Best Management Practices in an Impacted Agricultural Watershed in Florida, U.S.A.

Cited by 12 publications

References 83 publications

Evaluation of impacts of climate change on natural and managed wetland basins

Evaluation of impacts of climate change on natural and managed wetland basins

Put the Land Back on the Land: A National Imperative

The past, present, and potential future of phosphorus management in the Florida Everglades

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