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The Water Institute produces a range of scientific publications. In this way, we contribute to the state of the science, communicating cutting edge ideas to a broad technical audience.

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Particle tracking to examine sediment dynamics in a Mississippi River delta diversion

posted on 06.14.2017

Mead Allison, et.al., Author

In this article, "Observational and numerical particle tracking to examine sediment dynamics in a Mississippi River delta diversion," the authors use observational and numerical particle tracking to investigate the behavior of riverine sand and silt as it enters and passes through the West Bay diversion receiving-basin located on the lowermost Mississippi River delta, USA. River diversions may serve as useful restoration tools along coastal deltas experiencing land loss due to high rates of relative sea-level rise and the disruption of natural sediment supply. Diversions mitigate land loss by serving as new sediment sources for land building areas in basins proximal to river channels. However, because of the paucity of active diversions, little is known about how diversion receiving-basins evacuate or retain the sediment required to build new land.

Spatial and Temporal Patterns in Thalassia testudinum Leaf Tissue Nutrients at Chandeleur Islands

posted on 07.28.2017

Tim Carruthers, Kelly Darnell, et al., Author

Seagrasses are submerged marine plants that are anchored to the substrate and are therefore limited to assimilating nutrients from the surrounding water column or sediment, or by translocating nutrients from adjacent shoots through the belowground rhizome. As a result, seagrasses have been used as reliable ecosystem indicators of surrounding nutrient conditions. The Chandeleur Islands are a chain of barrier islands in the northern Gulf of Mexico that support the only marine seagrass beds in Louisiana, USA, and are the sole location of the seagrass Thalassia testudinum across nearly 1000 km of the coastline from west Florida to central Texas. Over the past 150 years, the land area of the Chandeleur Islands has decreased by over half, resulting in a decline of seagrass cover. The goals of this study were to characterize the status of a climax seagrass species at the Chandeleur Islands, T. testudinum, in terms of leaf nutrient changes over time, from 1998 to 2015, and to assess potential drivers of leaf nutrient content.

Water Resources Assessment for Sustainability and Energy Management

posted on 05.26.2017

Scott Hemmerling, Author

Effective water management is dependent on two primary factors; the availability of water and the costs to convert that water into a usable resource. The assessment framework developed here supports the effective management of Louisiana’s water resources by conjunctively appraising supply and demand in both ground and surface water units and providing a means to estimate the energy costs associated with water resources use. The framework includes a conceptual water budget that addresses both the total water supply and demand in different areas of the state, a water balance equation that mathematically relates the inputs and outputs of the hydrologic system in these areas, and a method for estimating the energy costs associated with extracting, treating, and conveying this water for public use. Access the report here

Building community and coastal resilience to a changing Louisiana coastline through restoration

posted on 04.24.2017

Tim Carruthers, Scott Hemmerling, et. al., Author

Bridging scientific working groups with community input, the “Building community and coastal resilience to a changing Louisiana coastline through restoration of key ecosystem functions,” looks at how local knowledge and values can be used to shape ecosystem restoration investments.

“Ecosystem based restoration approaches can support a range of ecosystem functions, such as reducing waves or providing nursery habitat for fish, these translate into a range of protection, social and economic benefits to communities,” said Tim Carruthers, lead author of the report and Director of Coastal Ecology at the Institute. “Community resilience in coastal Louisiana depends on social, cultural, and economic wellbeing which is closely linked to maintaining or restoring intact and productive coastal habitats.” The full report is available here

Relationships between salinity and short-term soil carbon accumulation rates from marsh types across

posted on 03.21.2017

Melissa Baustian, et.al., Author

Published in “Wetlands,” this paper shows that although researchers found relatively little difference in the rates of this short-term accumulation across marsh types, as salinity in wetlands rises, the amount of organic carbon in soil that can accumulate as a buffer against relative sea level rise decreases. That also means freshening of certain wetlands with coastal restoration project such as sediment diversions being planned for the Mississippi River or even additional rainfall, can help wetlands regain some of this organic storage ability and perhaps give these areas a buffer against succumbing as quickly to higher water levels. 

Evaluation of Sediment Diversion Design Attributes and Their Impact on the Capture Efficiency

posted on 02.02.2016

Ehab Meselhe, Author

Many riverine systems have been disconnected from their receiving basins by flood-protection levees and other engineered systems. Reconnecting these alluvial rivers with their receiving basins is a viable option to nourish and sustain existing coastal wetland systems as well as to build new land. This sediment nourishment can be accomplished through direct dredging and placement or through sediment diversions. Efficient design of sediment diversions is important to maximize the land building potential. This study’s objective is to quanti- tatively identify key design attributes of sediment diversions, influencing their ability to capture sediment. The outfall channel alignment angle (ϕ), intake invert elevation, and diversion size are hypothesized as key parameters. The analysis is limited to sediment grain sizes larger than 63 μm and has been performed using a validated three-dimensional numerical model. Click here to view the full publication. 

Application of Species Distribution Models to Identify Estuarine Hot Spots for Juvenile Nekton

posted on 12.14.2016

Ann Hijuelos, Author

Modeling the distribution and habitat capacities of key estuarine species can be used to identify hot spots, areas where species density is significantly higher than surrounding areas. This approach would be useful for establishing a baseline for evaluating future environmental scenarios across a landscape. We developed species distribution models for early juvenile life stages of brown shrimp (Farfantepenaeus aztecus), white shrimp, (Litopenaeus setifurus), blue crab (Callinectes sapidus), and spotted seatrout (Cynoscion nebulosus) in order to delineate the current coastal hot spots that provide the highest quality habitat conditions for these estuarine-dependent species in Louisiana. Response curves were developed from existing long-term fisheries-independent monitoring data to identify habitat sustainability for fragmented marsh landscapes. Response curves were then integrated with spatially explicit input data to generate species distribution models for the coastal region of Louisiana. Using spatial auto-correlation metrics, we detected clusters of suitable habitat across the Louisiana coast, but only 1% of the areas were identifies as true hot spots with the highest habitat quality for nekton. The regions identifies as hot spots were productive fringing marsh habitats that are considered the most vulnerable to natural and anthropogenic impacts. The species distribution models identify the coastal habitats which currently provide the greatest capacity for key estuarine species and will be used in the Louisiana coastal planning process to evaluate how species distributions may change under various environmental and restoration scenarios. Click here to view the full publication. 

Global Risks and Research Priorities for Coastal Subsidence

posted on 03.14.2017

Mead Allison, Brendan Yuill, et. al. , Author

Coastal lowlands, which rise less than 10 meters above sea level, are particularly vulnerable to the climate change effects forecast for the 21st century. Threats include inundation by accelerating sea level rise and increases in severity and frequency of tropical storm surges. These threats coincide with a worldwide surge in human population in coastal areas. Coastal population centers include several megacities, whose populations exceed 10 million. Many of these coastal megacities are located on river deltas that are also major centers for agriculture, fisheries, and hydrocarbon production. To make matters worse, many coastal areas are sinking even faster than the waters are rising: Natural and human-driven subisdence rates arising from shallow processes can be 1-2 orders of magnitude greater than the rate of climate-driven sea level rise predicted for the remainer of the 21st century. 

Influence of the Mississippi River on Pseudo-Nitzschia spp. Abundance and Toxicity in Louisiana

posted on 08.22.2016

Melissa Baustian, Author

Melissa Baustian co-authored "Influence of the Mississippi River on Pseudo-nitzchia spp. Abundance and Toxicity in Louisiana Coastal Waters". The presence of domoic acid (DA) toxin from multiple species of Pseudo-nitzschia is a concern in the highly productive food webs of the northern Gulf of Mexico. The report documents the Pseudo-nitzschia presence, abundance, blooms, and toxicity over three years along a transect ∼100 km west of the Mississippi River Delta on the continental shelf.


Hydrologic Modeling in a Marsh–Mangrove Ecotone: Predicting Wetland Surface Water and Salinity Respo

posted on 09.17.2015

Ehab Meselhe, Author

At the fringe of Everglades National Park in southwest Florida, United States, the Ten Thousand Islands National Wildlife Refuge (TTINWR) habitat has been heavily affected by the disruption of natural freshwater flow across the Tamiami Trail (U.S. Highway 41). As the Comprehensive Everglades Restoration Plan (CERP) proposes to restore the natural sheet flow from the Picayune Strand Restoration Project area north of the highway, the impact of planned measures on the hydrology in the refuge needs to be taken into account. The objective of this study was to develop a simple, computationally efficient mass balance model to simulate the spatial and temporal patterns of water level and salinity within the area of interest. This model could be used to assess the effects of the proposed management decisions on the surface water hydrological characteristics of the refuge. Click here to view the full publication.