Presented to the Faculty
of the University of Alaska Anchorage
in Partial Fulfillment of the Requirements
For the Degree of
MASTER OF CIVIL ENGINEERINGA three-dimensional unsteady flow numerical model was developed to study
sediment transport due to tidal circulation within Knik Arm, a dynamic well mixed
macro-tidal sub-estuary of Cook Inlet in Alaska. The model was developed to gain a
better understanding of the mechanisms that are creating the Point MacKenzie Shoal,
located approximately 4 kilometers south of Port MacKenzie. Hydrodynamic conditions
within the estuary are very complex in that ebb-and-flood tides, freshwater mixing, and
wetting/drying of tidal mud flats significantly effects sediment transport within the
estuary.
A Mike 3 numerical model was applied to simulate the sediment transport within the
estuary under the action of tidal currents in the vicinity of the shoal. The computational
domain of this simulation includes four sediment laden freshwater sources; Matanuska,
Knik, Susitna, and Twenty-Mile Rivers as well as an open ocean boundary. The spatial
resolution of the triangulated flexible mesh model is 0.00045 degrees2 with a coupled fine
resolution model of 0.000045 degrees2.
The results of the numerical model are in agreement with previously collected field
data. Simulation results indicate the shoal formation is the result of turbid tidal flows and
deposition is occurring naturally.Signature Page / Title Page / Abstract / Table of Contents / List of Figures / List of Tables / Background / Introduction / Physical Setting / Sediment / Freshwater Sources / Water Properties / Tidal Datum / Numerical Model / Model Selection / Methodology / Model Domain / Hydrodynamics / Sediment Transport / Summary of Model Input / Results and Discussion / Conclusion / Acknowledgments Reference
