A theoretical and field-based study on the formation and shape of fluvial levees. $110,000.
Rivers run through nearly every environment on earth and they are the primary conduits for sediment and water transported from source to sink. The natural levees on the river margins are important, yet understudied features. Levees influence large-scale stratigraphy (sandbody connectivity, for example) because they control sediment transfer between channel and floodplain, and floodplain accretion rate. Despite this importance, we do not have basic models that predict levee occurrence or shape.
Here I propose a theoretical and field-based study designed to answer two fundamental questions: 1) under what geomorphic and hydrodynamic conditions will levees form? and 2) what process-related variables control their profile shape?
To answer these questions I will develop a 1D morphodynamic levee model. The model will solve conservation of mass and momentum for water and sediment along a cross-section perpendicular to the channel and will be coupled to an analytical solution of the Navier-Stokes equations that solves for the downstream flood velocity. The numerical experiments will explore how the hydrodynamic and sedimentologic controls on levee occurrence and shape. Model predictions will be compared to levees on reaches of the White River and Muscatatuck River, Indiana, USA. Levees on the Muscatatuck River are more prevalent compared to the White. On each river I will characterize levee shape, sedimentology of the levee and floodplain, and sedimentology and hydrology of the modern channel. The field data will be used to constrain model predictions and provide empirical insight into the above questions.
Sustainability of Deltaic Coasts – The Trillion Dollar Problem. $3,000,000, 7 Co-PIs, $232,615 to Edmonds
Most major human population centers are located on deltaic coasts because of their rich fertile soils and plentiful natural resources. Unfortunately, it is not clear if human occupation on and near many coastal river deltas is sustainable. Deltas all over the world are disappearing, largely a result of the combined effects of anthropogenic changes to sediment supply and river flow sufficient to counter subsidence and sea level rise.
The proposed DELTA SEES project will explore the co-evolution of deltaic landscapes and human system response by focusing on changes in coastal flood risks due to human manipulations of sediment delivery. Through coupled field studies of human and environmental variables, integrated by physical, ecological, and human community modeling, we will test how these changes in actual and perceived risks of increased floods from cyclones contribute to significant reorganization of human settlement in coastal areas. We submit that testing these system interactions in the modeling framework proposed will produce foundational knowledge that can be used to evaluate potential impacts of relative sea level rise of deltaic coasts around the world.
We propose a research program that utilizes three experimental coastal basins in central Mississippi River Deltaic Plain with distinct history of sediment delivery by rivers and wetland loss responses. Patterns of landscape and human response to sediment delivery rates will be investigated with integrated modeling and observations to develop a systems analysis of how deltaic landscapes and the human system co-evolve around flood risks. DELTA SEES broader impact activities will be focused in four primary areas: graduate/undergraduate education, publication, policy applicability of discovery from our research, and public and K-12 outreach. These are all unified through the general recognition in Louisiana (like many other deltaic coasts) that the science of deltaic restoration has strong and direct impacts on local welfare and economies.
A dynamic delta collaboratory, $5,000,000, 14 co-PIs, $300,000 to Edmonds
River deltas represent a major Earth-surface system with societal need. Low-lying, ecologically productive, and inhabited by millions of people, deltas also lie directly in the path of a confluence of ongoing changes: nutrient overloading from agriculture; accelerated subsidence and sea-level rise; effects of land use and navigation; and changing hydrology and sediment supply.
The overall objective of this proposal is to develop tested, high-resolution, quantitative models incorporating morphodynamics, ecology, and stratigraphy to predict river delta dynamics over engineering to geologic time-scales, and to specifically address questions of system dynamics, resiliency, and sustainability.
We will do this by establishing the Delta Dynamics Collaboratory (DDC) for multi-investigator, interdisciplinary investigations of river delta sedimentary and ecologic dynamics. The lead institution for DDC will be the University of Texas, Austin, currently the center of delta prediction efforts for the National Center for Earth-surface Dynamics (NCED). The collaboratory will comprise two main work centers: a field observatory and a virtual modeling center, together with supporting experimental facilities.
The observatory will be at Wax Lake Delta, a manageably small (140 km2), actively growing delta about 100 km west of the main Mississippi Delta birdsfoot. The main observational goal will be to create a network of self-activating sensors to monitor delta behavior during major events (storms, river floods) that will complement an intensive survey program to measure ecosystem properties and relate them to high-resolution topography, bathymetry, and flow fields.
The virtual modeling center will be hosted by the Community Surface Dynamics Modeling System (CSDMS) at University of Colorado, where it can contribute to an evolving library of modules for computation and visualization of geomorphic and sedimentary systems, including access to many of the existing delta models. These two centers will be supported by experimental programs at the universities of Minnesota, Illinois, and Texas, and computational programs at Penn State, Boston College, Louisiana-Lafayette, Minnesota, Illinois, and Texas.
Dr. Doug Edmonds
Department of Earth and
1001 E. 10th St.
Bloomington IN 47405