sessions 21-30
Tuesday, May 20 | 4:00 – 5:30 p.m.
Sessions
• #21 Leveraging Disaster Recovery Funds to Support Professional Resilience Occupations
• #22 A Birds Eye View: Education and Development of Geoinformatics In Coastal Louisiana
• #23 Oyster Shell Recycling and Reef Restoration in the Gulf of Mexico
• #25 Water Quality and Harmful Algal Bloom Monitoring and Characterization (Part II of II)
Tuesday, May 20 | 4:00 – 5:30 p.m. | Room 286
#21 Leveraging Disaster Recovery Funds to Support Professional Resilience Occupations
Join us for an in-depth exploration of the Professional Resilience Occupations (PRO) Program, a groundbreaking initiative by the Louisiana Office of Community Development-Disaster Recovery and the Louisiana Community and Technical College System to support workforce development related to occupations critical to disaster recovery. This session will delve into the development and successful implementation of a major project aimed at expanding Heavy Equipment Operator training/certifications across Louisiana.
The PRO Program, launched to enhance workforce skills and support resilience efforts, effectively met its objectives ahead of schedule. We will discuss the four major phases of project implementation:
1. Initiation: Learn how the project was defined, including its scope, goals, and sustainability studies, setting the stage for a successful launch.
2. Planning: Discover the planning involved, from the selection of colleges, marketing and outreach efforts, industry impact and performance metrics.
3. Execution: Gain insights into the execution phase, highlighting how the project team managed tasks, coordinated efforts, ensured quality, and tracked progress to train approximately 300 LMI individuals in Heavy Equipment Operations Levels One and Two.
4. Expansion: The project exhausted all grant funds initially awarded and secured a Phase 2 award, demonstrating its success and sustainability.
Moderator: Micaela Coner – Louisiana Office of Community Development – Disaster Recovery
Panelists:
• Susan Nealy – Louisiana Office of Community Development – Disaster Recovery
• Tiffany Howard – South Louisiana Community College
• Jessica Lemoine – Louisiana Community and Technical College System
• Bridget LaBorde – Northshore Technical Community College
Organizer: Susan Nealy – Louisiana Office of Community Development – Disaster Recovery
Tuesday, May 20 | 4:00 – 5:30 p.m. | Room 287
#22 A Birds Eye View: Education and Development of Geoinformatics In Coastal Louisiana
As an area experiencing dramatic geographic changes, Coastal Louisiana benefits from the educational development and implementation of Geoinformatics (Geographic information systems (GIS), Aerial Photogrammetry, Remote Sensing (RS), Uncrewed Aerial Systems(UAS), Digital Twins, Geodesy, and Surveying) based programs. A combination of educators, graduates/students and industry professionals make up a cross-sectional panel of the people and programs on the leading edge of Coastal Geoinformatics in Southeast Louisiana. The panel will focus on the main question of how we can develop a deeper understanding of geographic changes and analysis in Coastal Louisiana and build a workforce to meet the needs of a changing climate. The panel will discuss educational opportunities by highlighting various types of programs available, industry partnered internship opportunities, student centered service learning projects, the impact educational programs are having on the coastal field and why building capacity for geoinformatics is an asset for the future of our coast.
Moderator: Arlo Townsley – CSED
Panelists:
• Madeline Foster-Martinez – University of New Orleans
• Balaji Ramachandran – Nicholls State University
• Jacqueline Richard – Nunez Community College
Organizer: Arlo Townsley – CSED
Tuesday, May 20 | 4:00 – 5:30 p.m. | Room 291
#23 Oyster Shell Recycling and Reef Restoration in the Gulf of Mexico
Oysters are a vital component of a healthy estuary as well as the seafood industry in the Gulf of Mexico, but are in severe decline throughout the region. Oysters also improve water quality and can stabilize shorelines against erosion. Collecting discarded shells from restaurants to return to coastal habitats for substrate is a critical effort towards a more sustainable future. Oyster shell recycling is gaining recognition around the country and has been employed in the northeast region for over two decades but is still new in the Gulf of Mexico. With support from NOAA, Restore America’s Estuaries (RAE) is working with five regional organizations to develop and expand their oyster shell recycling and reef restoration programs. A major component of this program is building a community of practice among the five organizations so they can learn from each other’s experiences. The program also includes support for monitoring and evaluation, not only to ensure that the reefs meet NOAA’s standards, but also to provide a basis for future reef design. Community engagement is another core component of the program. In particular, Coalition to Restore Coastal Louisiana (CRCL) is fostering ties with trial communities through creation of new oyster habitat that protects culturally important sites. This panel discussion will include presentations followed by Q&A and panel discussion with staff from RAE (the project manager), CRCL and Alabama Coastal Foundation (two participating groups), and Freese & Nichols, the consultant that designed the monitoring protocols.
Moderator: Hilary Stevens – Restore America’s Estuaries
Panelists:
• Mark Berte – Alabama Coastal Foundation
• Darrah Bach – CRCL
• Fiona Lightbody – CRCL
• Whitney Broussard – Freese & Nichols, Inc
Organizer: Hilary Stevens – Restore America’s Estuaries
Tuesday, May 20 | 4:00 – 5:30 p.m. | Room 292
#24 Impacts on the Marine Ecosystem of the Mississippi Sound and Bight from Freshwater Inputs and Environmental Stressors
The Mississippi Sound and Bight hosts a complex coastal marine system that experiences tropical storms, influx from freshwater diversions, seasonal stratification, frequent bottom hypoxia, harmful algal blooms and diverse fluvial inputs. Fisheries of note include eastern oyster (Crassostrea virginica), brown shrimp (Farfantepenaeus aztecus), blue crab (Callinectes sapidus) and gulf menhaden (Brevoortia patronus). Eastern oysters have long been a preferred target for regional management and restoration efforts, given the wide-ranging economic and ecological benefits they provide. Since 2010, oyster production in MS Sound has been severely curtailed, or completely shut down, due to the Deepwater Horizon oil spill and more frequent operations of the Bonnet Carré Spillway. Opening the BCS in Louisiana flushes the Mississippi Sound and Bight with river waters that are low in salinity and high in nutrient levels and suspended sediment loads, which can lead to ecosystem shifts, harmful algal blooms, and hypoxia. Long-term trends associated with climate change have increased the frequency of BCS operations such that for the first time ever it was opened for three years in succession (2018, 2019 and 2020) as well as twice in a single calendar year (2019). After the double BCS openings in 2019, intense cyanobacteria blooms were observed in Lake Pontchartrain and along the Mississippi coast, causing extended beach closures and marine mortality, with detrimental effects on coastal fisheries and local tourism.
Moderator: Paul Mickle – Northern Gulf Institute
Presenters:
• Isaac Mudge – US Army Corps of Engineers
• Brandy Armstrong – University of Southern Mississippi School of Ocean Science and Engineering
• Jerry Wiggert – University of Southern Mississippi School of Ocean Science and Engineering
• Mustafa Kemal Cambazoglu – University of Southern Mississippi School of Ocean Science and Engineering
• Vladimir Alarcon – Northern Gulf Institute
• Jessica Pruett – University of Southern Mississippi
• Scott Milroy – University of Southern Mississippi School of Ocean Science and Engineering
• Kim de Mutsert – University of Southern Mississippi School of Ocean Science and Engineering
• Chet F. Rakocinski – University of Southern Mississippi School of Ocean Science and Engineering
• James Klein – Mississippi Department of Marine Resources
Organizer: Paul Mickle – Northern Gulf Institute
Estimating Watershed Contributions into Lake Pontchartrain and the Mississippi Sound
Madalyn Mouton – USACE-ERDC-CHL
The Gulf Coast of the United States is a vital ecological zone contributing significantly to US economic and strategic security, with Lake Pontchartrain being a key feature. The lake supports diverse aquatic and bird habitats essential for ecological and economic functions. Its ecological balance relies on the interplay between tidal exchange and freshwater inflows, which are frequently disrupted by rainfall and runoff events, including flow releases through the Bonnet Carré spillway. Runoff from the Lake Pontchartrain and Mississippi Sound watersheds significantly affects the system’s dynamics and circulation. Effective management requires understanding the roles of catchment inflows and the spillway in lake circulation. USGS stream gauges measure water volumes from major rivers like the Amite and Tangipahoa Rivers, but they do not cover the entire basin or smaller streams. Similarly, gauges for the Pearl and Mobile Rivers in the Mississippi Sound watershed do not extend to their shoreline. Our study estimates the full freshwater input for the Lake Pontchartrain and Mississippi Sound basins from 2004 to 2023 using GIS processing and the ModelMyWatershed online tool. We employ distance weighting, linear regression, and ratios of area, slope, and curve numbers, combined with watershed land cover and slope data, to provide spatially resolved daily average freshwater contributions from each river. This allows us to better understand their impact on the estuarine system. The study identifies wet, dry, and normal years for the basins during the period along with a water budget.
msbCOAWST: Providing Reliable Science-based Information for Regional Restoration and Coastal Protection Programs
Brandy Armstrong – University of Southern Mississippi School of Ocean Science and Engineering
The University of Southern Mississippi (USM) modeling group has developed a daily hindcast and a short term (48 hour) forecast of the Mississippi Sound and Bight region. Called msbCOAWST, this 400 m resolution, 24-layer circulation model is based on a regional Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) application established during the GoMRI-funded CONCORDE consortium. This numerical model of water quality and hydrodynamic conditions in the Western Mississippi Sound captures the complicated dynamics of the coastal ocean which are necessary to assess habitat sustainability and climate change response. msbCOAWST is being integrated with in situ sampling, laboratory and field-based investigations, and remote sensing observations to provide reliable science-based information for planning regional restoration and coastal protection programs. Model output is being analyzed to study the many challenges and disruptions experienced in the Mississippi Sound including interannual variability, freshwater influx events, habitat suitability, ecosystem response, and the physical mechanisms that influence low oxygen events. This presentation will focus on the utility of the daily hindcast and forecast and the ways in which it can provide long-term, science-based guidance for resource management within the Mississippi Sound.
The Impact of Interannual Trends in Freshwater Inputs on the Hydrodynamics and Marine Ecosystem of the Mississippi Sound and Bight
Jerry Wiggert – University of Southern Mississippi School of Ocean Science and Engineering
Over the past decade, Mississippi Sound has been subjected to profound interannual variation in Mississippi River inflows that have led to the most active application of human managed diversions as well as interventions intended to inhibit saltwater intrusions threatening upstream freshwater supplies. As a means of assessing large-amplitude interannual variations in freshwater flows affecting the living marine resources of the Mississippi Gulf Coast, the University of Southern Mississippi modeling group has applied a 400 m resolution, 24-layer circulation model of the Mississippi Sound and Bight (msbCOAWST), which utilizes the Coupled Ocean Atmosphere Wave Sediment Transport modeling system. Our model is designed to support the coastal management community, providing the tools and resources needed to better evaluate complex scientific issues and inform natural resource management decisions. msbCOAWST has been configured to explicitly include riverine diversion constructs, both extant and proposed, that affect the estuarine and shelf waters of the MS Sound/Bight. Here, we apply our modeling framework to characterize how the hydrodynamic environments resulting from the unprecedented repeat openings of the Bonnet Carré Spillway (2018-2020) contrast with the hydrodynamic conditions resulting from the reduced freshwater inflows of recent years. Within this context, the climatological (i.e., business as usual) solution is used for further insight toward assessing how interannual trends linked to climate change are affecting regional hydrodynamics, water quality and marine ecosystem processes.
Operational Impacts of Bonnet Carré Spillway on The Mississippi Sound and Bight
Mustafa Kemal Cambazoglu – University of Southern Mississippi School of Ocean Science and Engineering
The Bonnet Carré Spillway (BCS) is a flood control structure on Mississippi River (MSR) and has recently been operated for 3 years in a row in 2018, 2019, and 2020; and for twice in a calendar year (2019) for the first time ever. The amount of MSR water diverted into Lake Pontchartrain (LP) during BCS openings vary depending on the length(duration) of the operations and the number of gates opened. The additional input of riverine water combined with the natural riverine input impacts the circulation and water quality in Mississippi Sound. In this study, we investigate the impact of recent BCS openings on the interconnected estuarine system within Mississippi Bight (MSB). We also hypothesize that modified BCS openings by controlling the opening pace (gates opened per day) and intensity (maximum number of gates opened) may reduce the impact of BCS on estuarine waters and we develop flood management scenarios to investigate the variability of BCS impacts.
The Coupled Ocean Atmosphere Wave Sediment Transport modeling system for MSB (msbCOAWST) is used to hindcast past BCS openings (2018, 2019 and 2020) and also to simulate varying opening scenarios such as: 2019 without the second opening; 2019 with shorter second opening; openings reducing the MSR discharge to 1.2 million cfs and 1.25 million cfs; slower-paced openings with 10 bays opened per day, are investigated.
The amount of river water introduced to the estuarine system during the most recent BCS openings varied from 87-to-347% of the entire LP volume. Preliminary results of hypothetical scenarios indicate that those amounts could be reduced to 40-to-82% if the MSR hydrograph could be kept at a minimum of 1.25 million cfs. The slower-paced opening scenarios also lead to a reduction in the amount of diverted riverine waters. We investigate the impact of such changes on the bottom salinity variability in the Mississippi Sound and Bight which is a critical stressor for marine life and especially for oysters.
Conceptual model for water quality simulation in the Mississippi Sound, USA
Vladimir Alarcon – Northern Gulf Institute
The first step on developing a water quality model is the conceptualization of the problem in a simplified version of reality that captures the pollutant sources, the receiving water body, and the boundary conditions. In this paper, a conceptual model for water quality simulation in the Mississippi Sound is presented. Nutrients, salinity, suspended solids, and chlorophyll-a observed data are used to present the framework on which a water quality model will be developed. Observed precipitation, salinity, TKN, TP, suspended solids, chlorophyll-a, and turbidity data collected at USGS and MDEQ monitoring stations in the Mississippi Sound indicate that Bonnet Carre Spillway openings may affect water quality as eastward as Gulf Port (Mississippi). The effects seem to reach as southward as Grand Pass USGS stations and Cat Island (Mississippi). Based on this, two computational models are proposed: one would simulate hydrodynamics and water quality in Lake Pontchartrain, and the second model would simulate salinity, hydrodynamics and water quality in the MS Sound. Freshwater inputs from the Bonne Carre Spillway, Lake Maurepas, and Pearl, Jourdan, and Wolf rivers would be set up as freshwater boundary conditions. An ocean boundary containing tidal, salinity and water quality data would implement those forcings in the MS Sound model.
Historical and future stressors on oyster reefs in the western Mississippi Sound
Jessica Pruett – University of Southern Mississippi
The Mississippi Sound is a dynamic estuary that supports diverse and productive habitats. In particular, oyster reefs in the western Mississippi Sound provide important ecological, economic, and cultural benefits. However, since the early 1900s, oyster habitat in this area has declined significantly, with notable 21st-century losses following Hurricane Katrina and the Deepwater Horizon oil spill. This presentation examines the chronic and acute stressors that have contributed to long-term oyster population decline and the challenges hindering current restoration and recovery efforts. Historical overharvesting and channel dredging physically removed habitat, leading to declines in populations and oyster reef area. Changes in salinity regimes due to the leveeing of the Mississippi River have resulted in higher salinities, especially during drought conditions, which promote the proliferation of oyster predators and disease. Freshwater pulses from Bonnet Carré Spillway openings, Pearl River flooding, and/or heavy localized rainfall can lower salinities for sustained periods, resulting in mass oyster mortality. In the past decade, climate change-related precipitation events, such as the prolonged flood season requiring double Bonnet Carré Spillway openings in 2019, have altered water quality in the western Mississippi Sound, hampering restoration efforts and recovery of resilient oyster reefs in the western Mississippi Sound will require significant investment in rebuilding adult populations and enhancing habitat.
Modeled Impacts to Habitat Suitability of Oysters in Mississippi Sound following the 2019 Bonnet Carre’ Spillway Openings
Scott Milroy – University of Southern Mississippi School of Ocean Science and Engineering
In response to changing climate, flood protection response, and land use patterns, Mississippi oyster reefs have endured dramatic declines in recent years, particularly following the unprecedented 2019 Bonnet Carre’ Spillway (BCS) double-opening. For restoration efforts to succeed, it is critical to understand how changes to coastal water quality affect habitat suitability for the gamut of oyster age classes throughout the Mississippi Sound (MSS). To this end, Habitat Suitability Index (HSI) models were developed for the four different age classes of oyster (larvae, spat, seed, and sack) and their unique susceptibilities to the highly-variable temperature, salinity, dissolved oxygen, and total suspended substances (TSS) witnessed in the western MSS during the 2019 BCS releases, for the specific purpose of identifying the age class(es) most sensitive to water quality changes and to identify which specific environmental variable placed the greatest constraint on habitat suitability.
Investigating Alternative Bonnet Carré Spillway Operations on Fish and Shellfish in the Mississippi Sound and Bight
Kim de Mutsert – University of Southern Mississippi School of Ocean Science and Engineering
The Bonnet Carré Spillway (BCS) is a flood control structure on the Mississippi River (MR) and has recently been operated for 3 years in a row in 2018, 2019, and 2020; and for twice in a calendar year (2019) for the first time. The amount of MR water diverted into Lake Pontchartrain during BCS openings varies depending on the duration of the openings, and the number of gates opened. BCS openings impact the salinity, temperature and water quality of the Mississippi Sound and Bight (MSB). In this study, we investigate the impact of recent BCS openings on fish and shellfish species in the MSB by using a coupled modeling approach. We hypothesized that modifying the BCS openings by reducing the number of gates opened per day and the maximum number of gates opened during an opening may reduce the impacts of BCS openings on coastal and estuarine fish and shellfish species. To test this hypothesis, the Coupled Ocean Atmosphere Wave Sediment Transport modeling system for MSB (msbCOAWST) is used to hindcast past BCS openings (2018, 2019 and 2020), and to simulate varying opening scenarios such as: 2019 without the second opening; 2019 with shorter second opening; openings reducing the MSR discharge to 1.2 million cfs and 1.25 million cfs; and slower-paced openings with 10 bays opened per day. A new Ecospace model was developed using Ecospath with Ecosim (msbEcospace) and loosely coupled to msbCOAWST to evaluate effects on fish and shellfish in the same region. The msbCOAWST salinity and temperature output is used to simulate the effect of the above-mentioned scenarios on 35 fish and shellfish species at different life stages. Preliminary results show that impacts and reduction of impacts by reducing the pace and amount by which salinity is reduced varies by species, and is more pronounced in sessile species such as eastern oyster, and less pronounced in nektonic species such as white and brown shrimp.
Variability in Precipitation Drives Early Recruitment of the Eastern Oyster Crassostrea Virginica in Mississippi
Chet F. Rakocinski – University of Southern Mississippi School of Ocean Science and Engineering
In recent years, early oyster recruitment in Mississippi has been driven by climate-related variability in precipitation, as expressed by alternating periods of extreme wet and dry conditions. The primary deterrent to early oyster recruitment shifted from substrate limitation to recruitment limitation in 2019, when unprecedented freshwater discharge from the Bonnet Carré spillway completely decimated oyster spawning stocks. Consequently, early oyster recruitment was effectively eliminated in 2019. Extreme low salinity conditions prevailed throughout the 2021 oyster recruitment period due to elevated regional rainfall. In 2023, early oyster recruitment returned to high levels in conjunction with a historic drought. Thus early recruitment of oysters has been primarily regulated by climatic extremes in recent years. Early recruitment metrics including spat settlement as well as growth and mortality of transplanted hatchery-reared juvenile oysters varied spatially and between years in conjunction with salinity. Covariation in biotic factors associated with salinity, such as predation intensity, food quality, and disease also contribute to recruitment success. Extreme climatic events in conjunction with multiple stressors mediate the recovery of oyster resources in the Mississippi Sound estuary. The development of an adaptive oyster management strategy is essential in the face of current environmental challenges.
Salinity and food supply govern oyster larval performance and settlement potential in the western Mississippi Sound: a modeling study
James Klein – Mississippi Department of Marine Resources
Eastern oysters are vital estuarine inhabitants for the many ecosystem services and economic value they provide. Accordingly, oyster population reestablishment is critical in degraded oyster reef systems, such as the western Mississippi Sound, whereby repeated mass mortality events have depleted the local adult oyster stock. Consequent of multiple die-offs in the last decade, particularly culminating with the 2019 Bonnet Carré Spillway freshwater diversion, the western Mississippi Sound oyster population is recruitment-limited, indicating that population growth is constrained by the influx of new individuals capable of establishing themselves into the extant population. Therefore, oyster recovery requires an adequate larval stock capable of timely growth, development, and successful metamorphosis. Larval performance and settlement potential are influenced by ambient temperature, salinity, and food supply. Food quantity is important to larvae, but so is quality, as larvae require a balanced diet of lipids, proteins, and carbohydrates to sufficiently grow, develop, and survive through metamorphosis. In this study, in situ environmental data and food condition (seston) samples were collected at seven historic western Mississippi Sound oyster reefs through the 2021 and 2022 spawning seasons. Results were integrated into an established biochemically-based larval performance model to estimate periods conducive to metamorphic success. In 2021, larval survivorship was largely suppressed by prolonged low salinity. Enhanced larval survivorship in 2022 resulted from higher seasonal salinity, suggesting performance was primarily governed by the quality of available food. Additionally, oyster surveys were conducted throughout the 2022 spawning season to assess recruitment trends. Model-estimated settlement windows aligned very well with the observed-recruitment windows, validating the accuracy and predictive power of the model.
Tuesday, May 20 | 4:00 – 5:30 p.m. | Room 290
#25 Water Quality and Harmful Algal Bloom Monitoring and Characterization (Part II of II)
A quarter of Louisiana’s productive coastal landscape has been lost over the past century, and coastal Louisiana also faces the aggregate effects of excess nutrients introduced in the large Mississippi River/Atchafalaya Basin watershed which drains 41% of the continental United States. Nutrients stimulate phytoplankton growth in surface waters, which fuels the estuary food web. However, excess nutrients and water residence time can cause algal blooms, one of the primary stressors on coastal ecosystems. Loading rates of nitrogen and phosphorus can affect the species composition of the phytoplankton community and lead to harmful algal blooms.
In this session, water quality data from existing monitoring programs (Louisiana Department of Environmental Quality, Coastal Protection and Restoration Authority, Louisiana Department of Wildlife and Fisheries, and U.S. Geological Survey) are synthesized to characterize water quality conditions across Louisiana’s coastal landscape, with a focus on the Barataria Basin and the Chandeleur Islands region. Monitoring and characterization of HABs in Louisiana coastal waters is rapidly expanding with new tools and techniques that are highlighted in talks including new identification techniques and hyperspectral approaches.
Monitoring and characterization of water quality and HAB parameters and trends are vitally important for understanding how local baseline conditions fluctuate, and serve as inputs for planning and prediction of coastal projects.
Moderator: Angelina Freeman – CPRA
Presenters:
• Beth Stauffer – University of Louisiana at Lafayette
• Jennifer Raabe - University of Louisiana at Lafayette
• Lee Potter - Louisiana State University
• Dan Kroes – USGS
Harmful algae in Louisiana estuaries: species, toxins, and impacts in oyster-growing habitats
Beth Stauffer – University of Louisiana at Lafayette
Phytoplankton assemblages in Louisiana estuaries include toxigenic and nuisance harmful algal (HA) species that span the freshwater-marine continuum. For example, freshwater cyanobacteria and their toxins (including microcystins) are found on a near-annual basis in spillway-influenced Lake Pontchartrain waters and at persistent, low concentrations in estuaries further west. Marine HA species, including diatoms in the genus Pseudo-nitzschia, have been found in continental shelf waters off the Louisiana coast. However, coast-wide trends in HA species presence, abundance, toxin production, and impacts on economically- and ecologically important oysters remain unresolved. As part of the LO-SPAT project, HA species have been monitored since 2022 at five estuarine sites, all located in important oyster-growing regions (with co-deployed oysters at two sites). Early results from these efforts are revealing a large number of HA species present across sites and throughout the months, with some notable new insights. For example, extra- and intracellular microcystins occur at similar levels across sites; however, higher extracellular concentrations in more saline sites suggest significant cell leakage/lysis, possibly minimizing toxin ingestion by oysters. Toxin analyses in oyster tissues are underway to test this hypothesis. A wide range of marine HA taxa have been identified, including a bloom of the raphidophyte Chattonella sp. at sites primarily east of the Mississippi River. Molecular tools and brevetoxin analyses are helping to elucidate the species identification and impact of that bloom. This presentation will share a coast-wide view of HA dynamics in oyster-growing regions of Louisiana waters both now and in the future.
Accumulation of cyanotoxins in Louisiana estuaries and oysters at two oyster grow-out sites
Jennifer Raabe - University of Louisiana at Lafayette
Filter feeders in Louisiana estuaries experience shifting food supplies with inputs of enriched freshwater from the Mississippi-Atchafalaya River Basin (MARB), creating conditions favoring the advection and recruitment of toxigenic cyanobacteria. Previous studies in Louisiana found seasonal or year-round presence of cyanobacteria in the genera Microcystis and Dolichospermum and microcystins (MCs) – a suite of hepatotoxins that can accumulate in water and shellfish with negative effects on animal and human health. Raphidiopsis, a genus capable of producing the cyanotoxin cylindrospermopsin was also detected following a Mississippi River flood event. To understand accumulation of cyanotoxins in estuaries and shellfish, we analyzed cyanotoxins in water samples (intra- and extracellular toxins, qPCR), solid phase adsorption toxin tracking devices (SPATT), and oyster tissue (Crassostrea virginica) at two sites: mesohaline LUMCON (LU) and polyhaline Grand Isle (GI). Using qPCR (quantitative PCR), we detected low concentrations of M. aeruginosa and the presence of the microcystin gene (MCY). We also compared two antibody-based immunoassay approaches and paired chromatography-spectrometry methods for microcystin analyses in the complex oyster tissue matrix. MCs were detected in water at both sites with similar intracellular MC but higher extracellular MCs were observed at GI than LU (p < 0.01). SPATT MC and preliminary oyster tissue MC concentrations were similar at both sites (p = 0.88 and p = 0.19, respectively), but MC in both matrices had increased variability at LU. Results from this study are helping us better understand the risks associated with cyanotoxins in Louisiana estuaries and shellfish.
Phosphorus Dynamics and Harmful Algal Blooms in the Lake Pontchartrain Estuary
Lee Potter - Louisiana State University
Internal phosphorus (P) loading in shallow eutrophic lakes drives harmful algal blooms (HABs), making understanding P distribution across watersheds essential for mitigation. This study developed a watershed-scale P budget for the Lake Pontchartrain Estuary in southeastern Louisiana, USA, where HABs frequently occur along the north shore. A comprehensive sediment P distribution map and riverine P inputs were created to compare internally loaded P from estuary sediments to watershed-derived P. Monthly water samples from the main tributaries of Lake Pontchartrain were analyzed for total suspended solids, dissolved and particulate P, and ambient water quality. Sediment cores (0–5 cm and 5–10 cm) from 160 stations across the 1,631 km² estuary were assessed for total P, inorganic and organic P, bulk density, and organic matter. Sediment P within the estuary ranged from 5.67–757.31 mg kg⁻¹ (median = 408), with 93% as inorganic P. High P concentrations were found in fine-grained southwestern sediments influenced by the Bonnet Carré Spillway, which introduces nutrient-rich Mississippi River water and sediment to the estuary. North shore sediments, primarily sandy, had lower P levels (5.67–481.68 mg kg⁻¹, median = 264) but received significant bioavailable P fluxes from tributaries. Soluble reactive phosphorus (SRP) from northern tributaries averaged 0.04 mg L⁻¹, comprising 60% of total riverine P. Results suggest P from the Bonnet Carré Spillway accumulates in sediments. In contrast, northern tributary discharge contributes to HABs in the estuary in the warm summer months. Managing runoff in northern tributaries could reduce HAB occurrences along the north shore.
Sediment and nutrient deposition during a large-scale river diversion, the Bonnet Carré Spillway 2011, 16 and 19
Daniel Kroes – USGS
In hopes of reversing or slowing the decline of the Mississippi River delta, diversions have been built, and crevasses have been allowed to develop along the lower River. In addition to the possibility of building land, these diversions allow for the storage of nutrients within deposited sediments, reducing nutrient loading to receiving water bodies. Accreted land provides a buffer from coastal storm surge flooding. However, accurate measurement of subaqueous sediment accretion from these diversions has proven to be elusive. In this study we examined a large flood diversion, the Bonnet Carré Spillway (the Spillway). The Spillway was constructed in 1931 on the footprint of naturally forming crevasses that formed from 1849 to 1882 between the Mississippi River and Lake Pontchartrain. During Spillway operations in 2011, 2016, and 2019, discharge, suspended sediment and nutrient samples were collected upstream and within the Spillway. After closure, sediment accretion was measured for depth, particle size, bulk density, and carbon, nitrogen and phosphorous concentrations. Sediment fingerprinting was used to calculate bedload contributions in 2016 and 2019. During Spillway operation, teragrams of sediment and gigagrams of nitrogen and phosphorous were deposited. Substantial bedload contributions were found in the deposited material in all years. This study indicates that floodplain reconnection moves large masses of sediment and nutrients from the Mississippi River that are deposited on the Spillway during operation and a portion of those are exported to Lake Pontchartrain.
Tuesday, May 20 | 4:00 – 5:30 p.m. | Room 289
#26 Rethinking Flood Risk: Strategies for Resilience and Sustainable Development
This session examines strategies for addressing flood risks at various scales, from regional studies to local systems, offering insights into how communities can adapt to an increasingly flood-prone future. Presenters will highlight how St. Tammany Parish is leveraging land-use strategies to guide sustainable growth while mitigating flood risks, including the creation of resilience overlay zones and community-informed planning. Cutting-edge advancements in flood forecasting, like the City of Central’s integration of high-resolution weather data and hydraulic modeling, showcase how technology can empower communities with real-time flood warnings. The session also explores the impact of Calcasieu Parish’s comprehensive watershed modeling, which evaluated hundreds of mitigation projects to identify cost-effective solutions for flood resilience. An overview of the Louisiana Watershed Initiative will demonstrate how tailored planning approaches can address the unique challenges faced by diverse communities, from urban centers to rural areas, and from coastal regions to inland watersheds.
Moderator: Kathryn Keating – The Water Institute
Presenters:
• Evelyn Campo – Desire Line LLC
• Spencer Johnson – CSRS
• Brooke Newlin – C. H. Fenstermaker & Associates
• Krista Jankowski – Arcadis
Coastal Resilience Land Use Study: Addressing Flood Risk and Sustainable Development in St. Tammany Parish
Evelyn Campo – Desire Line LLC
South of the I-12, between Mandeville and Slidell, lies an area facing increasing pressure from both rapid development and significant flood loss. As both coastal and riverine flood risks increase, the Parish chose to re-evaluate its approach to zoning, infrastructure, and development. From this need came the Coastal Resilience Land Use Study, which provides a strategic framework to address these vulnerabilities and guide future growth within the Study Area—an approach that can also be adapted to address these challenges across the larger St. Tammany Parish.
Study recommendations promote lower-density development and resilient building techniques in flood-prone areas, protect critical wetlands, and call for infrastructure improvements. The introduction of “Resilience Overlay Zones” is a key feature, applying stricter building standards to areas at the highest flood risk. Community engagement also played a key role in shaping Study recommendations by providing insight into local needs and concerns. This presentation will highlight a successful approach taken by the Parish through land use studies, floodplain management tools, and community engagement. It aims to provide insight into how communities are addressing the dual challenge of increasing development pressure and managing flood risk into the future. Attendees will learn how community input has influenced planning decisions and enhanced flood resilience, offering lessons that can be applied to other coastal communities facing similar challenges.
City of Central Flood Warning System
Spencer Johnson – CSRS
CSRS has developed an advanced flood forecasting system for the City of Central, integrating NOAA’s High-Resolution Rapid Refresh (HRRR) precipitation forecast with real-time stream gauge data and a city-wide 2D hydraulic model. This system automates the generation and online publication of forecasted flood maps and hydrographs after each updated forecast. The HRRR model, a high-resolution (3 km) regional weather model for North America, provides hourly updates for 18 to 48-hour forecasts. A streamlined 2D HEC-RAS hydraulic model was developed, utilizing increased Manning’s n values at drainage structures to replace traditional 2D connections, reducing model run times to less than 5 minutes.
A custom MATLAB script polls NOAA’s NOMADS server for new forecast data. Upon detecting updated data, the script automatically downloads and formats it for use in the HEC-RAS model. NOAA’s Multi-Radar/Multi-Sensor (MRMS) recent historical precipitation data is used for each run’s initial conditions, ensuring that the evolving forecasts do not affect subsequent model runs. The hydraulic model then processes the data, generating flood depth and elevation rasters, which are uploaded to an online mapping platform for real-time public access. Additionally, forecasted stage hydrographs are produced at predefined locations, displaying projected water levels alongside critical elevations, such as bank or road heights. Planned future enhancements include additional forecasted precipitation data, continued model calibration efforts, and an improved interface geared to non-technical users.
Calcasieu Parish Watershed Modeling & Strategic Analysis
Brooke Newlin – C. H. Fenstermaker & Associates
As a part of the Calcasieu Parish Regional Watershed Management study, 12 watershed models were developed and calibrated/validated using the Parish’s extensive gauging system. These 2D watershed models were used to analyze the impact of various flood mitigation projects selected from a list of over 600+ proposed structural and nonstructural mitigation projects. All proposed projects went through a screening process to determine the most viable projects to undergo a hydraulic analysis. 50 proposed projects located throughout Calcasieu Parish were implemented in the 2D watershed models and then a benefit cost analysis was performed to determine which projects were most cost effective. Since the conclusion of the study earlier this year, Calcasieu Parish has utilized the results from this analysis to choose projects that can utilize the Hazard Mitigation Grant Program (HMGP) dollars the Parish received from the Federal Emergency Management Agency (FEMA) after Hurricane Laura.
Building Capacity for Effective Flood Risk Reduction Planning
Krista Jankowski – Arcadis
The state of Louisiana has a long history of managing and responding to flood risks. Whether fluvial, pluvial, tidal, or storm surge-related, flooding negatively impacts the people, communities, and economies of the state. Through efforts such as the Louisiana Watershed Initiative, communities across the state are endeavoring to address current and future flood risk head on. This presentation will provide an overview of the variety of flood risks Louisianans face, as well as insights into how regional and local circumstances influence flood related decision-making. There will be discussion of how through a combination of foundational vision and goal-setting and differentiated implementation, communities can ‘right-size’ their flood related planning and build their local capacity to address these ever more frequent and severe challenges. There will also be discussion of the unique considerations of rural and urban communities, coastal and inland locales, and starting points for communities with differing levels of initial staff capacity and critical resources.
Tuesday, May 20 | 4:00 – 5:30 p.m. | Room 288
#27 Central Wetlands Restoration: From Hydrologic Restoration to Vegetative Plantings
The Central Wetlands Unit is a critical landscape feature located southeast of New Orleans, LA. The CWU comprises 30,000 acres of degraded coastal habitat, including patches of freshwater swamp, oak ridge forest, intermediate/brackish marsh and submerged aquatic vegetation. Historically these ecosystems have been culturally important, providing valuable wildlife habitats and dampened wave and winder energy during hurricanes. However, the degradation of CWU ecosystems due to river management, oil and gas canals, and logging lowered the beneficial impact of these habitats. In August 2005, Hurricane Katrina storm surge was channeled up the Mississippi River Gulf Outlet Navigational Channel (MRGO). It caused significant devastation from flooding throughout the Lower 9th Ward neighborhood in Orleans Parish and towns across St. Bernard Parish which border the CWU. The closing of the MRGO via rock dam in 2009 lowered porewater salinity throughout the CWU and created favorable conditions for reforestation in some areas.
A variety of different restoration measures have begun in the Central Wetlands Unit ranging from vegetative plantings, hydrologic restoration through gapping of canals, and the planned future operation of the violet siphon to introduce freshwater from the Mississippi River. This session will discuss past present and future restoration plans, from the grassroots campaign to close of MRGO, to current restoration efforts happening with plantings through the Central Wetlands Reforestation Collective, gapping in inundated marshlands and future hydrologic restoration with the use of the Violet siphon.
Part 1: Restoration of the Central Wetlands: Multiple Strategy and Cross-Agency Approach
Federal, State and Parish governments have all made efforts to undo the destruction caused by MRGO and Hurricane Katrina to the Central Wetlands Unit. In this sessionfirst panel discussion we will hear from conservation leaders who will speak to large scale restoration projects in all phases of completion to advance this goal. We will hear from the campaign to close the Mississippi River Gulf Outlet which has stopped the salt water intrusion, the history of planting in Central Wetlands following the closure of MRGO, ongoing efforts to connect the wetlands to freshwater inputs via hydrologic restoration projects along the Violet Canal, as well as MRGO Ecosystem Restoration Plan.
Moderator: Gardner Goodall – Coalition to Restore Coastal Louisiana
Panelists:
• April Newman – Coastal Protection and Restoration Authority
• Amanda Moore – National Wildlife Federation
• Darrel Broussard – U.S. Army Corps of Engineers
• Blaise Pezold – Meraux Foundation
Organizer: Gardner Goodall – Coalition to Restore Coastal Louisiana
Part 2: Central Wetlands Reforestation Collective: Swamp Restoration in Orleans and St. Bernard Parishes
The Central Wetlands Reforestation Collective (CWRC) is a group of regional organizations that have worked to support the CWU region over the last decade; they include the Meraux Foundation, Common Ground Relief, the Center for Sustainable Engagement and Design, the Pontchartrain Conservancy and the Coalition to Restore Coastal Louisiana. In 2018, partner organizations began habitat restoration activities across the CWU, and in 2023 the partner organizations formalized their relationship to better coordinate on individual projects, shared goals, and to maximize reforestation efforts, which include planting 30,000 Cypress/Tupelo trees, 33,000 marsh grasses, 3,000 oak ridge species, and 1,000 SAV plants over the next four years. CWRC activities support other large-scale restoration projects in the CWU, including the D.U./NAWCA 40 Arpent terraces Phase 1 and 2, Coastal Protection and Restoration Authority’s plan to install gaps throughout the CWU, which allows for better hydrologic connectivity, and which would be reinforced by the operation of the Violet Siphon, which reconnects Mississippi River water to the CWU.
This second panel discussion plans to cover the background, origin, processes, hurdles, and preliminary outcomes of implementing the first two years of this multi-year, multi-organizational project.
Moderator: Gardner Goodall – Coalition to Restore Coastal Louisiana
Panelists:
• Andrew Ferris – Coalition to Restore Coastal Louisiana
• Eva Hillman – Pontchartrain Conservancy
• Rollin Black – L9 Center for Sustainable Engagement and Development
• Christina Lehew – Common Ground Relief
Organizer: Andrew Ferris – Coalition to Restore Coastal Louisiana
Tuesday, May 20 | 4:00 – 5:30 p.m. | Room 285
#28 Hydrology and Morphology Related to Land Building and Flood Mitigation
This session will explore the dynamic interplay between sediment transport, flood control, and land-building processes along the Louisiana coast and how innovative sediment management, engineering techniques and modeling strategies can enhance coastal sustainability and flood resilience. Presentations will explore traditional assumptions about the role of sand-free mud in land creation, as informed by the unexpected formation of “Harold’s Island” in the Atchafalaya pro-delta; the role of strategic elevation of dredged material in Soft Sediment Marsh Creation (SSMC) projects; how rising water levels contribute to prolonged flooding and reduced drainage efficiency in the West Cote Blanche and Vermillion Bay region; and how large-scale watershed models can streamline hydraulic assessments to inform flood management strategies and these models more accessible and effective for localized applications.
Moderator: Will Norman – SWCA Environmental Consultants
Presenters:
• John Day – LSU
• Chris Russo – DDG
• Ranjit Jadhav – Olsson
• Justin West – Michael Baker International
Building and sustaining mud island habitat offshore in the Atchafalaya River pro-delta
John Day – LSU
In early August, 2024, Harold Schoeffler, a well-known sportsman from Lafayette, noticed an uncharted 25-acre island crowded with pelicans 12 km into the Gulf of Mexico from Eugene Island, and 2 km west of the Atchafalaya River Navigation Channel (ARNC). Upon further inspection, “Harold’s Island” was found to be a sparsely vegetated mudflat surrounded by “fluid mud,” a dense clay slurry with the consistency of yogurt. Raymond ‘Mac’ Wade, Director of the Morgan City Harbor and Terminal District (MC District), confirmed that the island location had been used for permitted dredged sediment disposal from the ARNC for almost a decade, but the island did not appear until 2022. The MC District has collaborated with the Louisiana Department of Wildlife and Fisheries (LDWF) and the US Army Corps of Engineers (USACE) to build hundreds of acres of sandy deltaic islands in Atchafalaya Bay. But it was not believed possible to create land offshore using sand-free mud from the Atchafalaya River “pro-delta.” Routine channel maintenance is now carried out by an innovative, small agitation dredge that continuously ‘sweeps’ vast quantities of fluid mud from the channel bed and sends it downdrift toward the island before it can consolidate. After waves generated by Hurricane Francine moved massive volumes of mud into the ARNC on September 10, 2024, additional measures are clearly necessary. LSU researchers will be analyzing ways to lower channel maintenance costs while also improving techniques to build and sustain new mud islands in the Atchafalaya pro-delta.
Use of Instrumented Settlement Plates in Soft Sediment Marsh Creation Projects
Chris Russo – DDG
Soft Sediment Marsh Creation (SSMC) projects face challenges, particularly in achieving the desired Constructed Marsh Fill Elevation (CMFE) for project resilience post-construction. The success of SSMC hinges on the strategic elevation of dredged material within the Marsh Creation (MC) template. Large MC areas pose difficulties in reaching target elevations without excessive fill in one location or internal dikes, both detrimental to the project. A balanced approach, distributing fill evenly over a longer time period, may not reach the target elevation but achieves the necessary material density. Monitoring with Instrumented Settlement Plates (ISP), density sampling, and other field checks allows for tracking project success against settlement curves and design expectations. Thus, project evaluation focuses on design-compliant volume placement while minimizing negative impacts.
Settlement plates are simple instruments that provide direct measurements of soil settlement beneath placed soils. Pressures are applied via hydraulic or mechanical placement of dredged material, which is received by a transducer (pressure plate) and a vibrating wire piezometer. A logger reads the data from these instruments, enabling the user to calculate the effective stress exerted over a given area. This effective stress is directly related to the amount of material being placed within a Marsh Creation Area (MCA).
The typical fill procedure calls for uniform placement of material, so the pressure produced at any point in the cell should be representative of the entire MCA, consisting of similar soils. Although data points are discrete and specific to their locations, the collected data can be applied to a larger general area throughout the MCA. The extracted data is then combined with the dredged material depth and proximity and formatted into a user-friendly format to read out the effective stress of the material, as shown below.
Drivers of Drainage Hydrology of the Coastal Watershed West of Atchafalaya River
Ranjit Jadhav – Olsson
The coastal region adjoining West Cote Blanche and Vermillion Bay of the Gulf of Mexico is susceptible to flooding resulting from local rainfall, storm surge and Sea Level Rise (SLR). In recent years, the local landowners have experienced slower drainage following meteorological events. The purpose of this study was to evaluate the general drainage potential of this region and the influence Atchafalaya River, SLR, the Jaws terracing project, and silting of Jaws Bay waterways using a hydraulic model. Existing water levels and flow data were analyzed to examine long-term trends in hydrology of the region. A two-dimensional HEC-RAS model of the study area was developed and used to evaluate alternatives of dredging the Wax Lake Outlet (WLO)and Jaws Bay, and a structure on GIWW. Analysis showed that controlling westward flow in GIWW of water from the Lower Atchafalaya River results in little to no reduction of water levels. The dredging of Jaws Bay shows little reduction in water levels and drainage duration. Deeper dredging shows some benefits which is unlikely to keep up with the SLR. The observed data analysis showed that the regional water levels are rising at a rate of 0.05 ft per year, consistent with SLR observed along the rest of the Gulf coast.
Leveraging Large Scale Watershed Models for Use in Smaller Scale Project Level Analysis
Justin West – Michael Baker International
Large-scale watershed models are becoming available as Federal and State Agencies have realized their benefits in analyzing flood mitigation related projects. The complex and time-consuming models can seem dauting for professionals and is met with apprehension resulting in the professional preferring to producing smaller scale, local hydraulic models from scratch. Consequently, the large-scale models, despite their potential utility, remain underutilized. This redundancy wastes valuable resources and overlooks the data and insights already embedded in the HUC8-sized models. To address this, Michael Baker International in collaboration with St. Tammany Parish, leveraged previously developed HUC8 models produced under the Louisiana Watershed Initiative currently being executed by LA DOTD. Models were utilized in two separate Parish sponsored projects of varying scale. The first is a parish wide Comprehensive Drainage Plan aiming to create easy to use breakout hydraulic models, detailed design plans, and a flood mitigation capital improvement plan. The second project consists of reducing the size of a HUC8 model to design and determine flood mitigation benefits of a regional detention project. Leveraging the HUC8 models for local projects is successful but require an organized set of procedures derived through trial and error. By enhancing usability, the investment in the original HUC8 models can continue to provide value. The simplified models have proven effective for parish/county-level projects highlighting adaptability and innovation in watershed management.
Tuesday, May 20 | 4:00 – 5:30 p.m. | Room 284
#29 The Renewables and Resilience Nexus
Renewable energy resources, such as solar power and energy storage systems, offer critical support for enhancing coastal resilience. This panel will examine how these technologies can help mitigate the socio-economic impacts of storm-driven power outages and increase energy security for vulnerable coastal communities. Panelists will highlight successful distributed solar projects, discuss their impacts, and explore strategies for scaling these solutions across the region to strengthen both energy infrastructure and community resilience.
Moderator: Cameron Poole – GNO Inc.
Panelists:
• Anna Nguyen – Office of Resilience & Sustainability City of New Orleans
• Pierre Moses – 127 Energy
• Neal McMillin – Louisiana Department of Energy & Natural Resources
• Monika Gerhart – Gulf States Renewable Energy Public
Organizer: Cameron Poole – GNO Inc.
Tuesday, May 20 | 4:00 – 5:30 p.m. | Room 283
#30 Reading, writing and the river: Two authors who have published books focused largely on the Mississippi River talk about their works with journalist Mike Smith
John Barry published the influential “Rising Tide” in 1997, exploring the story of the Mississippi River and the Great Flood of 70 years earlier. The flood and the response to it in New Orleans were turning points for our state and indeed for the nation. The book was described by The Washington Post as “a big, ambitious book that is not merely engrossing and informative but also has the potential to change the way we think.” Barry also served for six years on the board of the state Coastal Protection and Restoration Authority and the Southeast Louisiana Flood Protection Authority – East. Two decades after “Riding Tide,” Boyce Upholt published his “The Great River,” which is billed as explaining how “centuries of human attempts to own, contain, and rework the Mississippi River … have now transformed its landscape.” The authors will talk about their craft and their books in a conversation with journalist Mike Smith, environmental editor at The Times-Picayune/Advocate/nola.com
Moderator: Mike Smith – The Times-Picayune/Advocate/nola.com
Panelists:
• Boyce Upholt – Author
• John Barry – Author
Organizer: James Karst – CRCL