RESEARCH PROJECTS
Research at the Center for Wetlands advances a systems understanding of the interconnected dynamics among water, wetlands and watersheds. By integrating field observations, long-term monitoring and modeling, we examine how hydrologic, ecological and human processes interact across scales, and develop actionable tools for management, restoration and policy.
Integrating modeling tools and observations for prediction and management of harmful algal blooms in the St. Lucie Estuary and Watershed (SLEW)
PROJECT OVERVIEW
Lake Okeechobee and the St. Lucie and Caloosahatchee River watersheds comprise a vitally important and environmentally sensitive ecosystem. Harmful algal blooms (HABs) occur when rapid growth of algae leads to an accumulation of individual cells that, in turn, discolor water, often produce floating mats that emit unpleasant odors, and may negatively impact fish, birds, shellfish and other animals. HABs ultimately lead to many negative impacts to the environment, public health and the state economy. Water quality in the St. Lucie estuary and watershed are influenced by ecological stressors including urban development, agricultural land use, a highly variable salinity regime, and inflows from regulatory Lake Okeechobee releases during heavy rainfall and severe storm events.
The project team is working to support the development of new state-of-the-art water quality data and models to better predict and manage harmful algal blooms in the St. Lucie estuary and watershed. The three-year grant will fund the development of a new decision support system that will allow end-users to rapidly interpret short-term forecasts, predict future HABs, and deliver crucial information and tools. The research team is taking a multidisciplinary approach to fill any knowledge gaps by utilizing water resources modeling, water quality monitoring, physical oceanography, stakeholder engagement, and HAB source tracking, characterization, and prediction.
Sponsor: U.S. Army Corps of Engineers Engineering Research and Development Center, Principal Investigators: Mauricio Arias (mearias@usf.edu) and David Kaplan (dkaplan@ufl.edu), Start Date: April 2021, Project Size: $2.1 million.
Coupling lake, watershed, and estuarine models to better understand the role of engineered freshwater discharges in driving the severity, location, and timing of harmful algal blooms
PROJECT OVERVIEW
Severe freshwater and marine harmful algal blooms (HABs) in Florida’s lakes, rivers and estuaries have resulted in tremendous environmental and economic damages in recent years. In southwest Florida, blooms are becoming more frequent, more damaging, and longer lasting, threatening the health and well-being of coastal communities. The goal of this project is to develop data- and model-supported guidance for water management to prevent or reduce the impact of harmful algal blooms across the region, which responds to an increasing call for more scientifically supported water- and nutrient-management strategies, particularly for Lake Okeechobee. This project is led by CFW Director David Kaplan, Ph.D., and involves Elise Morrison, Ph.D., (UF, ESSIE), Edward Phlips, Ph.D., (UF| IFAS), Natalie Nelson, Ph.D., (North Carolina State University), Maurcio Arias, Ph.D., (University of South Florida) and Eric Milbrandt, Ph.D. (Sanibel-Captiva Conservation Foundation).
Sponsor: U.S. Army Corps of Engineers Engineering Research and Development Center, Principal Investigator: David Kaplan (dkaplan@ufl.edu), Start Date: October 2021, Project Size: $2.3 million.
The EPA’s National Condition Wetland Assessment aims to quantify the condition of our nation’s wetlands
PROJECT OVERVIEW
The Environmental Protection Agency’s National Wetland Condition Assessment is a survey aiming to quantify the condition of our nation’s wetlands. The first survey was conducted in 2011, and the assessment is repeated every five years. Data from 1234 wetlands surveyed in 2011 and 2855 wetlands surveyed in 2016 are available on the EPA’s website. The Howard T. Odum Center for Wetlands has performed field research and analysis for Florida for each iteration of the NWCA. To assess the ecological condition of each wetland, vegetation, soil, and water chemistry samples and hydrology, weather, buffer, and general field observations are collected. These factors are evaluated to reflect key stress indicators and ecological health for each region within the USA. The number of wetlands surveyed in each state is related to the state’s total wetland area. In Florida, which has the largest wetland area of any state other than Alaska, 50 wetlands were surveyed in the summer of 2021.
Funded by the UF Office of Research, CAPES – Brasil, and the UF Water Institute. The Amazon basin hosts an extremely valuable conglomeration of ecological and social systems, harboring complex feedback systems and providing innumerable ecosystem services. The Brazilian government plans the rapid development of a vast network of hydroelectric dams and supporting infrastructure in the Amazon over the following decades. This will not only directly impact river hydrology and biology, but will also generate land-use changes, such as deforestation, that will impact the hydrologic cycle and biodiversity on a regional scale, driving the likely loss of myriad ecosystem services. In October 2014, a team of UF faculty from the Amazon Dams Network (ADN) was awarded the 2015 Water Institute Graduate Fellows (WIGF) Program to study the complex and interactive set of impacts brought about by the construction and operation of dams and other hydraulic infrastructure in the Amazon. The ADN team’s proposal, “Hydrologic transformation in the Amazon basin: reconciling economy, society, and the environment in the world’s largest watershed” is led by David Kaplan, Ph.D., with co-PIs Stephanie Bohlman, Ph.D., and Denis Valle, Ph.D., (School of Forest Resources and Conservation), Kai Lorenzen, Ph.D., (School of Natural Resources and Environment), and Cynthia Simmons, Ph.D., and Bob Walker, Ph.D. (Geography). The award supports six new doctoral students.
Funded by all five Florida Water Management Districts, FL Department of Agricultural and Consumer Services. While the perceived benefits of forest management are often limited to habitat improvement, specific management actions that reduce forest biomass (from thinning and prescribed fire) may also have implications for regional water yield. Because evapotranspiration (ET) dominates ecosystem water losses in the southeastern US, even modest reductions in the proportion of rainfall lost to ET (e.g., from 90% to 80%) can result in large fractional increases (e.g., doubling) in water yield. In previous work, we developed a statistical model of water yield as a function of management strategy, stand structure, and ecosystem water use. Results suggested a potential increase in water yield of up to 64% for pine stands managed at lower basal relative to systems managed for high-density timber production, but identified critical sources of uncertainty, including the effects of climatic variation, between-site variability, water use in young pine stands, and prescribed fire. In upcoming work, we aim to reduce uncertainty around projected water yield subsidies from modified management. To quantify the effects of land management on forest biomass, ET, and water yield, we will apply a comparative evaluation across a gradient of environmental conditions (soil type, aquifer confinement and climate). Within each site, treatments (i.e., plots) target variation in management activities (e.g., thinning, clearcutting and fire) and forest biomass. Groundwater and soil moisture data are used to construct daily vadose zone and aquifer water budgets to determine ecosystem ET and water yield. Preliminary total ET data from a slash pine stand in north central Florida show good agreement with independent ET estimates derived from eddy correlation measurements, suggesting that this relatively low-budget approach can provide ET measurements at scales and costs requisite for understanding the role of land on local and regional water yield.
Funded by St. Johns River Water Management District, University of Florida University Scholars Program. One of the most pressing issues facing Florida’s waterways is anthropogenic nitrate pollution due to more than fifty years of rapid population growth and increased agricultural activity. In light of recently declared numeric nutrient criteria, an understanding of nutrient cycling processes is crucial for proper water management practices. In-stream nitrate removal due to denitrification is thought to be positively correlated with high velocity gradients and increased hyporheic exchange. However, previous studies in tidally influenced springsheds have noted greater nitrate retention at lower velocities possibly due to increased residence times. This study aims to identify the connection between water velocity, hyporheic exchange and nitrate removal rate using the biologically reactive tracer resazurin to directly measure the amount of spring discharge subject to hyporheic exchange under varying flow conditions. Tracer studies will be performed during various stages of the tidal cycle and breakthrough curves of resazurin and its byproduct resorufin will be analyzed and compared to in-situ nitrate measurements to determine the contributions of residence time and hyporheic exchange to nitrate cycling. Identifying the driving hydraulic force in denitrification could aid in future restoration and water treatment decisions as well as predictions of how aquatic ecosystems will respond to changing hydrologic conditions including flooding, drought and groundwater recharge and depletion.
Funded by Florida SeaGrant. Oyster reefs have been shown to provide myriad critical ecosystem services, however their role in directing flow and currents during non-storm conditions has been largely neglected. In many regions, oyster reefs form as linear structures perpendicular to the coast and across the path of streams and rivers, potentially entraining large volumes of freshwater flow and altering nearshore mixing. We hypothesize that these reefs have the potential to influence salinity over large areas, providing a “keystone” ecosystem service by supporting multiple estuarine functions. Here we present results from a field and modeling study to quantify the effects of reef extent and elevation on estuarine salinities under varying river discharge. We found salinity differences ranging from two to 16 g/kg between inshore and offshore sides of degraded oyster reefs in the Suwannee Sound (FL, USA), supporting the role of reefs as local-scale freshwater dams. Moreover, differences between inshore and offshore salinities were correlated with flow, with the most marked differences during periods of low flow. Hydrodynamic modeling using the 3-D Regional Ocean Modeling System (ROMS) suggests that the currently degraded reef system entrained greater volumes of freshwater in the past, buffering the landward advance of high salinities, particularly during low flow events related to droughts. Using ROMS, we also modeled a variety of hypothetical oyster bar morphology scenarios (historical, current and “restored”) to understand how changes in reef structure (elevation, extent and completeness) impact estuarine mixing and near-shore salinities. Taken together, these results serve to: 1) elucidate a poorly documented ecosystem service of oyster reefs; 2) provide an estimate of the magnitude and spatial extent of the freshwater entrainment effect; and 3) offer quantitative information to managers and restoration specialists interested in restoring oyster habitat.
Funded by US Fish and Wildlife Service, Florida Department of Economic Opportunity. Sea level rise (SLR) is a growing concern ecologically and economically for coastal communities in Florida and around the world. Coastal regions are particularly susceptible to local changes in sea level resulting from increased temperatures, changing winds and currents, and subsidence. This study examines the interacting effects of SLR, climate change, groundwater supply and land use on saline and freshwater vegetation communities along the Big Bend region of Florida. Data from hydrological monitoring and vegetation transects will be collected at three primary locations along Florida’s Gulf Coast: Lower Suwannee National Wildlife Refuge, Waccasassa Bay, and Withlacoochee Bay. Previous vegetation data collected in Waccasassa Bay will be pooled with this current research to conduct a long-term analysis on the impacts of SLR and salt water intrusion on species composition and population dynamics in coastal forests. Field data will be supplemented with publicly available data on vegetation communities, species composition, land use and topography in Withlacoochee Bay to create a baseline against which future SLR impacts can be projected. This study also includes the development of long-term adaptation strategies for incorporation into municipal policy and planning documents to help coastal communities preserve natural resources vulnerable to SLR.
Funded by US Environmental Protection Agency. The US Environmental Protection Agency (EPA) has embarked on a nationwide National Aquatic Resource Survey (NARS) to access the condition of the Nation’s lakes (field work in fiscal year (FY07), rivers (FY08), streams (FY09), coastal waters (FY10), and wetlands (FY11). As part of the larger NARS project, the University of Florida-H.T. Odum Center for Wetlands (UF-CFW) project specifically focuses on participation in the statewide assessment of wetland condition as part of the US EPA National Wetland Condition Assessment (NWCA) 2011. Information collected from this assessment will be used by the US EPA in support of the first ever nation-wide evaluation of wetland condition based on chemical, physical, and biological parameters. The NWCA uses a probability-based sample design, resulting in a statistically valid estimate of condition for a population of wetlands. During the execution of the NWCA, Level II Rapid Assessment and Level III Intensive Site Assessment will be conducted through the Level II US Rapid Assessment Method (US-RAM) and Level III field and laboratory studies on algae, vegetation, water and soil chemistry, hydrology and buffers.
Funded by US Environmental Protection Agency. The University of Florida-H.T. Odum Center for Wetlands in cooperation with the monitoring and assessment needs of the Florida Department of Environmental Protection with funding through the US Environmental Protection Agency have begun work to supplement the National Wetland Condition Assessment (NWCA) 2011. Funds from this grant will be used for monitoring program improvements within Florida. The funds will enhance FDEP’s ability to assess waters, report on overall condition and obtain the needed water quality information to develop and assess protective numeric water quality criteria. Four specific project tasks include further development of statistically-valid assessments of waters, procurement of monitoring equipment (i.e. dissolved oxygen probes), enhancements to biological monitoring (e.g. field testing of Florida Wetland Condition Index (FWCI) against NWCA, determination of temporal variability in vegetation, and monitoring to support development of water quality criteria.
Funded by US Environmental Protection Agency Region IV. This project builds on the US Environmental Protection Agency (EPA’s) National Wetland Condition Assessment (NWCA) 2011 by performing geographic information systems (GIS) based site evaluation and a Level I Landscape Assessment of 67 wetland assessment points located within the state of Florida. Through the use of the Level I Landscape Assessment using the Landscape Development Intensity index this project seeks to link the Level II Rapid Assessment and Level III Intensive Site Assessment with the landscape scale and demonstrates a remote office based tool to evaluate wetland condition to support monitoring capacity of the state’s wetland resources.
Funded by US Environmental Protection Agency. Recent rulings by the U.S. Supreme Court have limited federal protection over isolated wetlands, requiring documentation of a “significant nexus” to a navigable water body to ensure federal jurisdiction. Despite geographic isolation, isolated wetlands influence surficial aquifer dynamics that regulate baseflow to surface water systems. To explore the importance of this function at the landscape scale, we integrated models of soil moisture, upland water table and wetland stage to simulate the hydrology of a low-relief, depressional landscape. We quantified the hydrologic buffering effect of wetlands by calculating the change in standard deviation of water table elevation between landscapes with and without wetlands for different soil types. Increasing wetland area and/or density reduced water table variability relative to landscapes without wetlands, supporting the idea that wetlands stabilize regional hydrologic variation, but also increased mean water table depth because of sustained high ET rates in wetlands during dry periods. Considering the influence of regional water table on downstream systems, these results suggest that isolated wetlands help regulate regional surface waters through an indirect, but significant nexus. Read the paper in Water Resources Research.
Funded by St John’s River Water Management District. A research project to build and test a pilot-scale floating modular treatment system consisting of interchangeable biological and physical-chemical treatment modules for TP removal from tributaries to Lake Jesup.
Funded by Florida Department of Environmental Protection.
Funded by Florida Institute of Phosphate Research. This research project was a five-year investigation of wetlands on Clay Settling Areas (CSAs) to develop knowledge and understanding of their ecology and hydrology for establishing functional wetlands and to suggest ways to enhance their creation. The project documented the current status and historical trends of wetlands naturally establishing on CSAs, evaluated CSA hydrologic regimes, evaluated CSA ecohydrology, developed temporal and spatial hydrologic models of wetlands on CSAs, conducted short- and long-term field trials that documented survival and growth of herbaceous and forested wetland plant species, and synthesized project findings into guidelines for enhancement of existing wetlands and the creation of new ones on CSAs.
Funded by Arkansas Soil and Water Conservation Commission. The project developed an appropriate land use classification scheme from existing Land use/land cover, collected energy and material flow data and calculated empower densities for land use classes, and developed LDI coefficients for land use classes from empower densities.
Funded by Florida Institute of Phosphate Research. This research addresses the development and application of the trajectory approach to assessing adequate site progress toward ecological goals for created forested wetlands on phosphate mined land. The final report can be found on the Florida Institute of Phosphate Research’s web site: http://www.fipr.state.fl.us/, FIPR Publication #03-142-231.
Funded by the Florida Department of Environmental Protection. The project developed a web-based training manual designed to help users “walk-through” the process for conducting an evaluation under the newly adopted Unified Mitigation Assessment Method (UMAM). Additionally, the training manual provides some background and ancillary data on landuse, water quality, hydroperiods and natural community guides. UMAM is now applied statewide to assess the value of wetlands and other surface waters and determine the amount of mitigation needed to offset adverse impacts. A link to the manual is available on the Uniform Mitigation Assessment Method Toolbox page from the Florida Department of Environmental Protection’s website.
Funded by Florida Department of Environmental Protection. This project was a pilot study including 24 forested strand and floodplain wetlands. It developed biological indicators throughout Florida using sturctural metrics for the macrophyte community. Landscape Development Intensity index and soil quality were also determined. The final report is available on-line through the University of Florida Digital Collections website:
https://ufdc.ufl.edu/AA00004283/00001
Funded by Florida Department of Environmental Protection. This project developed biological indicators for depressional forested wetlands throughout the entire state of Florida using sturctural metrics for the benthic diatom, macrophyte and benthic macroinvertebrate communities. Landscape Development Intensity (LDI) index, water quality and soil quality were also determined. The final report is available on-line through the University of Florida Digital Collections website:
https://ufdc.ufl.edu/AA00004284/00001
Funded by Florida Department of Environmental Protection. Methods to quantify the relative condition of isolated herbaceous wetlands in Florida were identified using macrophytes, macroinvertebrates and diatoms. The metrics were combined to create the Florida Wetland Condition Index for herbaceous wetlands.
Funded by Florida Institute of Phosphate Research.
Funded by Florida Institute of Phosphate Research. Studies of wetlands developing on phosphate mined lands and under controlled greenhouse conditions were conducted to evaluate the role of early successional species in ecosystem development. The project focused on primrose willow (Ludwigia peruvianna), cattail (Typha sp.), Carolina willow (Salix caroliniana) and vines. Persistence under reduced light, nutrient cycling and nutrient sequestration were studied, as well as their role in developing and altering the physical environment (microtopography). Finally, measurable wetland attributes showing directional change with time were identified, and models of successional trajectories were established from attribute data, including tree height, dbh, canopy cover, soil organic matter content and bulk density. The final report is available on-line from the Florida Institute of Phosphate Research: http://www.fipr.state.fl.us/, FIPR Publication #03-131-193.
Funded by Florida Department of Health.
Funded by South Florida Water Management District. Developed tools for the assessment of stormwater retrofitting designs in urban areas. Particular emphasis was on modeling to evaluate various conceptual plans, including geographic location of treatment sites, total area requirements and strategies of one single versus many small wetland systems.
Funded by Florida Institute of Phosphate Research.