Restoration and Water Management in the Atchafalaya River Basin, Louisiana

Restoration and Water Management in the Atchafalaya River Basin, Louisiana
Author: Justin P. Kozak
Publisher:
Total Pages: 0
Release: 2015
Genre: Atchafalaya River Watershed (La.)
ISBN:

Download Restoration and Water Management in the Atchafalaya River Basin, Louisiana Book in PDF, Epub and Kindle

Environmental restoration in aquatic systems requires innovative approaches that combine scientific understanding, socioeconomic demands, and local stakeholder values into decisions. However, changing approaches to water management to address these requirements is difficult because of scientific and socioeconomic uncertainty and institutional barriers that can prevent implementation of alternative water management approaches. Current restoration efforts in the Atchafalaya River Basin (ARB) of Louisiana are faced with this challenge. Water management in the ARB has evolved from strong federal control to establish the ARB as a primary floodway of the Mississippi River and Tributaries Project to a state and federal collaboration to accommodate fish and wildlife resource promotion, recreational opportunities, and economic development. While management policy has expanded to include a growing number of stakeholders, the decision-making process has not kept pace. Current conflicts among many local stakeholder groups, due in part to their lack of involvement in the decision-making process, impede restoration efforts. The absence of a long-term collective vision for the ARB by both local stakeholder groups and numerous management agencies further confounds these efforts. Here, I propose a process to apply a structured decision making framework, a values-based approach that explicitly defines objectives, to promote stakeholder-driven restoration efforts in the ARB and to better prepare for and manage long-term environmental issues. The goals of this approach are: 1) to create a process founded on stakeholder values and supported by rigorous scientific assessment to meet management agency mandates and 2) to establish a structure for restoration planning in the ARB that incorporates current and future non-governmental stakeholders into a transparent decision-making process. Similar frameworks have been successful in other river basins and the structure of current restoration efforts in the ARB is well-suited to adopt a values-focused management framework. Next, I use flow-ecology relationships to evaluate ecosystem service trade-offs and complementarities in the ARB to assess the potential impacts of water management decisions. Flow-ecology relationships were used to explore complementary and trade-off relationships among 12 ecosystem services and related variables in the ARB. Results from Indicators of Hydrologic Alteration were reduced to four management-relevant hydrologic variables using principal components analysis. Multiple regression was used to determine flow-ecology relationships and Pearson correlation coefficients, along with regression results, were used to determine complementary and trade-off relationships among ecosystem services and related variables that were induced by flow. Seven ecosystem service variables had significant flow-ecology relationships for at least one hydrologic variable (R2 =0.19-0.64). River transportation and blue crab (Callinectes sapidus) landings exhibited a complementary relationship mediated by flow; whereas transportation and crawfish landings, crawfish landings and crappie (Pomoxis spp.) abundance, and blue crab landings and blue catfish (Ictalurus furcatus) abundance exhibited trade-off relationships. Other trade-off and complementary relationships among ecosystem services and related variables, however, were not related to flow. These results give insight into potential conflicts among stakeholders, can reduce the dimensions of management decisions, and provide initial hypotheses for experimental flow modifications. The final study in this dissertation proposes an environmental flow prescription for the highly altered ARB. The development of the ARB into a floodway has contributed to hydrologic changes basin-wide that have altered the river-floodplain interface threatening important ecosystems, notably the expansive baldcypress-water tupelo swamp forests. Analysis of the current flow regime reveals a 12-92% increase in mean monthly discharge over the past 80+ years, but a 24-43% decrease in mean monthly stage in large portions of the basin. Current restoration efforts only address the spatial distribution of water in local areas of the basin; however the timing, frequency, magnitude, and duration of ecologically important high and low flows are determined at the basin-wide scale by the daily implementation of a federal flow mandate that limits available water management options. We used current hydrologic conditions and established flow-ecology relationships from the literature to develop an environmental flow prescription for the ARB that provides basin-wide flow targets to complement ongoing restoration efforts. The result is an adaptive flow regime that strives to balance important flow-ecology relationships within a decision space limited by a federal flow mandate. We found that lengthening the implementation of the current flow mandate to monthly or quarterly time scales has high potential for success in meeting both the flow mandate and important flow-ecology relationships.

Using 1D2D Modeling to Inform Restoration Efforts in the Atchafalaya River Basin, Louisiana

Using 1D2D Modeling to Inform Restoration Efforts in the Atchafalaya River Basin, Louisiana
Author: Anne Hayden-Lesmeister
Publisher:
Total Pages: 176
Release: 2018
Genre: Atchafalaya River (La.)
ISBN:

Download Using 1D2D Modeling to Inform Restoration Efforts in the Atchafalaya River Basin, Louisiana Book in PDF, Epub and Kindle

The Atchafalaya River Basin (ARB) in Louisiana is the principal distributary of the Mississippi River, and it contains the largest contiguous area of baldcypress-water tupelo swamp forests in North America. After designation of the ARB as a federal floodway following the destructive 1927 Mississippi River (MR) flood, it was extensively modified to accommodate a substantial portion of the MR flow (~30%) to mitigate flooding in southern Louisiana. The resulting reach to system scale modifications for regional flood mitigation, navigation, and hydrocarbon extraction have substantially altered the lateral connectivity between the AR and its floodplain wetlands, threatening the ecological integrity of this globally-important ecosystem. Multiple stakeholder groups agree that restoring flow connectivity is essential to maintaining the basin's water quality and forest health, and several flow-connectivity enhancement projects (hereafter, project elements) have been proposed by the Atchafalaya Basin Program's Technical Advisory Group within the Flat Lake Water Management Unit (FLWMU) study area to increase lateral hydrologic connectivity within the management unit and beyond. Additionally, a new flow prescription to improve floodplain habitat has recently been suggested for the ARB. Flow into the ARB is now regulated through the Old River Control Structure (ORCS; operational in 1963), and represents the opportunity for large-scale flow experiments to enhance a multitude of ecosystem services that have been degraded due to anthropogenic alteration. For this study, I compiled existing datasets and constructed a 1D2D hydraulic model to evaluate: 1) if the suggested flow prescription would have the desired inundation impacts; 2) whether the proposed project elements would improve lateral connectivity in the FLWMU; and 3) whether recommended project elements would increase the area suitable for baldcypress recruitment in the study area. I examine the first two research questions above, I examined two scenarios--a baseline scenario to examine current conditions (no restoration projects), and a full-implementation scenario, where all proposed project elements that could be examined at the model resolution were implemented. Comparison of the modeling results for the baseline scenario to the suggested flow prescription goals suggests the overbank discharge and the extreme low-flow targets would have the desired impacts of inundating and drying out of the majority of the FLWMU, respectively. Proxy indicators of enhanced flow connectivity suggest that proposed projects will improve water quality, especially at intermediate to high flow conditions, when ~90% of the FLWMU experiences improved drainage as indicated by higher rates of water surface elevation decrease and lower overall system water volume. The stated objectives of the project elements recommended by the Technical Advisory Group are to improve connectivity and water quality, but another important and related restoration goal for stakeholders includes baldcypress restoration. To examine the third objective, I used a model-derived proxy indicator of habitat improvement (depth reduction) at two key discharges, along with other ecological suitability factors, to determine areas most likely to support baldcypress recruitment. Here, I compared baseline conditions to two alternative restoration scenarios: 1) a targeted implementation scenario where 22 project elements were implemented, and 2) the full-implementation scenario, where all projects that could be examined at the model resolution were implemented. Suitable habitat area for both natural and artificial baldcypress recruitment increased under intermediate flow conditions but remained unchanged for higher discharge conditions. For the intermediate discharge scenario, the full-implementation scenario results in a 2 km2 increase in the class considered most suitable for natural baldcypress regeneration within the calculated recruitment band, and a decrease of ~16 km2 in the areas considered least suitable for the entire FLWMU study area. Coupled with the connectivity results, which indicate that nutrient-rich river water will be exchanged between main channels and the backswamp at a greater range of flows, it appears that project implementation alone will benefit baldcypress recruitment, especially artificial regeneration efforts. However, full project implementation coupled with large-scale flow modifications at ORCS would likely provide maximum benefit for baldcypress restoration efforts that seek to increase the area supportive of natural baldcypress regeneration.

The Atchafalaya River Basin

The Atchafalaya River Basin
Author: Bryan P. Piazza
Publisher: Texas A&M University Press
Total Pages: 513
Release: 2014-03-01
Genre: Nature
ISBN: 162349141X

Download The Atchafalaya River Basin Book in PDF, Epub and Kindle

In this comprehensive, one-volume reference, Nature Conservancy scientist Bryan P. Piazza poses five key questions: —What is the Atchafalaya River Basin? —Why is it important? —How have its hydrology and natural habitats been managed? —What is its current state? —How do we ensure its survival? For more than five centuries, the Atchafalaya River Basin has captured the flow of the Mississippi River, becoming its main distributary as it reaches the Gulf of Mexico in south Louisiana. This dynamic environment, comprising almost a million acres of the lower Mississippi Alluvial Valley and Mississippi River Deltaic Plain, is perhaps best known for its expansive swamp environments dominated by baldcypress, water tupelo, and alligators. But the Atchafalaya River Basin contains a wide range of habitats and one of the highest levels of biodiversity on the North American continent. Piazza has compiled and synthesized the body of scientific knowledge for the Atchafalaya River Basin, documenting the ecological state of the basin and providing a baseline of understanding. His research provides a crucial resource for future planning. He evaluates some common themes that have emerged from the research and identifies important scientific questions that remain unexplored.

Designing the Bayous

Designing the Bayous
Author: Martin Reuss
Publisher: Texas A&M University Press
Total Pages: 493
Release: 2004
Genre: Business & Economics
ISBN: 160344632X

Download Designing the Bayous Book in PDF, Epub and Kindle

:This history of the Atchafalaya Basin is an account of the transformation of an area that has endured perhaps more human manipulation than any other natural environment in the nation.

Water Resources Projects in Louisiana

Water Resources Projects in Louisiana
Author: United States. Congress. Senate. Committee on Environment and Public Works. Subcommittee on Water Resources
Publisher:
Total Pages: 876
Release: 1983
Genre: Dredging
ISBN:

Download Water Resources Projects in Louisiana Book in PDF, Epub and Kindle

The Atchafalaya River Basin

The Atchafalaya River Basin
Author: Bryan P. Piazza
Publisher: Texas A&M University Press
Total Pages: 322
Release: 2014-02-25
Genre: Nature
ISBN: 1623490391

Download The Atchafalaya River Basin Book in PDF, Epub and Kindle

In this comprehensive, one-volume reference, Nature Conservancy scientist Bryan P. Piazza poses five key questions: —What is the Atchafalaya River Basin? —Why is it important? —How have its hydrology and natural habitats been managed? —What is its current state? —How do we ensure its survival? For more than five centuries, the Atchafalaya River Basin has captured the flow of the Mississippi River, becoming its main distributary as it reaches the Gulf of Mexico in south Louisiana. This dynamic environment, comprising almost a million acres of the lower Mississippi Alluvial Valley and Mississippi River Deltaic Plain, is perhaps best known for its expansive swamp environments dominated by baldcypress, water tupelo, and alligators. But the Atchafalaya River Basin contains a wide range of habitats and one of the highest levels of biodiversity on the North American continent. Piazza has compiled and synthesized the body of scientific knowledge for the Atchafalaya River Basin, documenting the ecological state of the basin and providing a baseline of understanding. His research provides a crucial resource for future planning. He evaluates some common themes that have emerged from the research and identifies important scientific questions that remain unexplored.