Numerical modeling of the effects of hydrologic conditions and sediment transport on geomorphic patterns in wetlands
This dissertation focused on developing a numerical model of spatial and temporal changes in bed morphology of ridge and slough features in wetlands with respect to hydrology and sediment transport when a sudden change in hydrologic condition occurs. The specific objectives of this research were: (1) developing a two-dimensional hydrology model to simulate the spatial distribution of flow depth and velocity over time when a pulsed flow condition is applied, (2) developing a process-based numerical model of sediment transport coupled with flow depth and velocity in wetland ecosystems, and (3) use the developed model to explore how sediment transport may affect the changes in bed elevation of ridge and slough landscape patterns observed in wetlands when a conditional pulsed flow was applied. The results revealed the areas within deep sloughs where flow velocities and directions change continuously. This caused enhanced mixing areas within the deep slough. These mixing areas may have had the potential to affect processes such as sediment redistribution and nutrient transport. The simulation results of solute/sediment transport model also supported the existence of areas within the domain where the mixing processes happened. These areas may have caused that nutrients and suspended particles stay longer time rather than entraining toward downstream and exiting the system. The results of bed simulation have shown very small magnitude of change in bed elevation inside deep slough and no changes on the ridge portion of the study area, when a conditional pulsed flow is applied. These findings may suggest that implementing pulsed flow condition did not increase suspended sediment concentration, which results in insignificant changes in bed morphology of a ridge and slough landscape. Therefore sediment transport may not play an important role in wetland bed morphology and ridge and slough stability. Results from the model development and numerical simulations from this research will provide an improved understanding of how wetland features such as ridge may have formed and degraded by changes in water management that resulted from increasing human activity in wetlands such as The Florida Everglades, over the past decades.
Water Resource Management|Environmental engineering
Mahmoudi, Mehrnoosh, "Numerical modeling of the effects of hydrologic conditions and sediment transport on geomorphic patterns in wetlands" (2014). ProQuest ETD Collection for FIU. AAI3705085.