The effect of landuse change on the hydrologic, biogeochemical and
ecological response of watersheds is a concern throughout the world. To help
characterize the potential magnitude of such changes, and of the potential to
remediate or avoid undesirable features, studies focused on the cumulative
watershed effects of site level change are necessary. The current state of the art
model for water quality in agricultural lands, Soil Water Assessment Tool
(SWAT), was used to estimate the effects of a set of future landscape scenarios on
water quality in the Corn Belt region of the United States. These results indicated
that changes to the current water quality management strategies will be necessary
to significantly improve water quality in the Corn Belt region. In addition, the
experience of implementing SWAT suggested a variety of changes to the model
structure and study design with potential to improve the quality of the results.
These changes include improved treatment of hydrologic process, full integration
of input data and model code, different methods of distributing data across space,
the use of fewer parameters, more sophisticated numerical techniques, and
improved methods for generating potential landscape scenarios.
A new model structure (WET_Hydro) was developed to address these
issues. The hydrologic components of the model focus on a conceptual physically
based characterization of the movement of water in soils, as overland flow, and in
channels. Tests using a variety of input data sets, including both synthetic inflows
and real watershed data were developed to verify the hydrologic components of
the model. Additional model analyses evaluate how model scale interacts with
parameters and with measurements. These analyses point toward additional
criteria that may prove useful to the determination of correct model scales and to
the utility of the flexible model structure which provides automatic changes to
model scale. In addition to the scale analysis, a method of estimating the average
new water contribution to storm discharge was developed.. This additional model
criterion was shown to provide further understanding of model utility under
different hydrologic regimes.
The hydrologic model was extended to produce estimates of erosion and
sediment export. Sensitivity to various restoration options were developed
focusing on simple descriptions of remediation potential, and a minimum of
parameters. In addition, the water quality model was coupled with a Decision
Support System (DSS). Example applications demonstrate the potential of the
combination to improve the process of restoration planning at the watershed scale. / Graduation date: 2003 / Best scan available. Figures in original are very light.
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/31606 |
| Date | 11 February 2003 |
| Creators | Vache, Kellie B. |
| Contributors | Bolte, John P. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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