Abstract/Details

Effect of elevation resolution on evapotranspiration simulations using MODFLOW


2010 2010

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Abstract (summary)

The regional groundwater flow model of the Rincon Valley-Mesilla Basin area (NMOSE-2007 flow model) is revised in this work for use with the water managers of the region. A Groundwater Vistas (GV) based numerical model is developed to analyze the simulation results. Layer elevations derived from the revised hydrogeologic cross sections for the Mesilla Basin are incorporated. Model performance is improved by minimizing the uncertainty in input parameters specific to mountain front recharge and boundary flows.

Effect of model grid size to simulate the evapotranspiration (ET) component of groundwater is investigated in the present research. Source code of the evapotranspiration package (EVT) in MODFLOW is modified by solving the groundwater flow equation at the user specified digital elevation model (DEM) resolution. Uncertainty in groundwater depth at DEM resolution is eliminated by characterizing the variability in both land surface and piezometric elevations. An area of interest delineated by the boundaries of model grid cells is specified to minimize the runtime. A new option to approximate the ET represented area by the boundaries of the DEM cells is introduced to improve the model performance.

Applicability of the present research is evaluated on the modified NMOSE-2007 flow model. The 10 m DEM of the study area is aggregated to various coarse resolution grids that are integer multiples of model grid resolution. Model sensitivity to variability in elevation input data is investigated at different resolutions. Results of the analysis conclude that both cumulative ET outflows and ET rates from the model are decreasing towards coarse resolution grids. An optimum grid resolution by striking the balance between computational run time and model prediction accuracy is suggested for use with the head dependent packages. Statistical analysis on the estimated parameters conclude that simulating the ET component of groundwater at 80.487 m resolution and aggregating the ET outflows to model cell resolution would improve the performance of the model.

Indexing (details)


Subject
Hydrologic sciences;
Civil engineering
Classification
0388: Hydrologic sciences
0543: Civil engineering
Identifier / keyword
Applied sciences; Earth sciences; Elevation resolution; Evapotranspiration; Grid sizes; Groundwater; Head dependent components
Title
Effect of elevation resolution on evapotranspiration simulations using MODFLOW
Author
Kambhammettu, B.V.N. Phanindra
Number of pages
154
Publication year
2010
Degree date
2010
School code
0143
Source
DAI-B 71/11, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9781124281995
Advisor
King, James Phillip
University/institution
New Mexico State University
University location
United States -- New Mexico
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3428917
ProQuest document ID
845874437
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/845874437
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