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Temporal and Spatial Variability of Groundwater Nitrate in the Southern Willamette Valley of Oregon
Mutti Home Mutti Thesis Tabulated & GIS Data	Maps showing monthly groundwater nitrate concentrations for sample sites and their intra-well ranking are available below. A rank value (shown as the well label) of 1 indicates that the highest observed nitrate concentration for the well was made that month. High rank values indicate that observed well concentration was relatively low in a given month. The geologic map in the figures is from Gannett and Caldwell (1998). All files are .jpg images.
	Median Well Concentration (label is site ID instead of ranked concentration) August 2004 September 2004 October 2004 November 2004 December 2004 January 2005 February 2005 March 2005 April 2005 May 2005 June 2005 July 2005 August 2005 September 2005 October 2005
	Modeling of potential nitrate leaching was done using the Soil and Water Assessment Tool (SWAT). Output data compared with groundwater nitrate data indicates that SWAT reasonably models nitrate leaching, as shown here. Regions where discrepancies exist between modeled and observed data are in the south-central portion of the modeled area (between Coburg and Junction City) and are caused by the current model's inability to account for septic loading.
	Gannett, M.W., Caldwell, R.R., 1998, Geologic Framework of the Wilamette Lowland Aquifer System, Oregon and Washington: USGS Professional paper 1424-A, 32 p.