SWV2002GWStudyRpt.pdfINTRODUCTIONPURPOSE AND SCOPE OF THE STUDYThe study area includes the lowlands of the southern portion of the Willamette Valley, extending from Eugene to Albany in Lane, Linn, and Benton Counties (see Figure 2). Areas inside the urban growth boundaries of Eugene, Corvallis, Albany, and LebanSWV2002GWStudyRefs_Glossary.pdfREFERENCESSWV2002GWStudyAttachB.pdfDate Prepared: ____________Field Technician: __________________________Sample collected at: Tap? ______ Well head? ______ Hose bib? ______Field Sampling Parameters:Temperature ______ Conductivity______ D.O. ______ pH ______ Water Level ____SWV2002GWStudyAttachB2.pdfBlankSOUTHERN WILLAMETTE VALLEY 2002 GROUNDWATER STUDY FFiinnaall RReeppoorrtt May 2003 Audrey Eldridge, R.G. Regional Environmental Solutions and the Groundwater Quality Protection Program Western RegionPAGE Abstract 1 Introduction 2 Purpose and Scope 3 Description of the Southern Willamette Valley 4 Location of the Study Area 4 Land Uses 4 Hydrogeology 4 Study Design and Methods 7 Project Organization and Responsibilities 7 Selection of the Parameters 7 Sampling Design 8 Sample Collection Methods 8 Results of the 2002 Sampling & Analyses 9 Overview 9 Nitrate 10 Bacteria 11 Total Coliform 11 E.Coli 11 Pesticides 11 Atrazine and Desethyl-atrazine 12 Simazine 12 Terbacil 12 Bromacil 13 Malathion 13 Bisphenol-A 13 Metribuzin 13 Other Pesticides 13 Other Inorganics 14 Discussion 14 Nitrate 14 Pesticides 18 Atrazine 19 Desethyl-atrazine 19 Simazine 20 Other Pesticides 21 Caffeine 22 Conclusions 22References Glossary Appendices Attachment A: 2002 Project Roles and Responsibilities Attachment B: Field Data and Well Site Identification Sheets Attachment C: 2002 Analytical Results Attachment D: Pesticide Procedure LIST OF FIGURES Figure 1: Locale of Study Area Figure 2: Location of the Southern Willamette Valley Study Area Figure 3: Southern Willamette Valley Hydrogeologic Units Figure 4: Nitrate Results from the 2002 sampling event relative to the Upper Sedimentary Unit (Younger) Figure 5: The main stem of the Willamette River relative to the Upper Sedimentary Unit (Younger) Figure 6: Locations where pesticides were detected in the 2002 sampling event, relative to the Upper Sedimentary Unit (Younger) Figure 7: Locations of selected pesticide detections from the 2002 sampling event LIST OF TABLES Table 1: Areas where nitrate levels were greater than or equal to 15 mg/l Table 2: Areas where nitrate levels were greater than or equal to 10 mg/l and less than 15 mg/l Table 3: Areas where nitrate levels were less than 10 mg/l Table 4: Results for Infrequent Pesticide Detections Table 5: Results for Inorganic ParametersSouthern Willamette Valley 2002 Groundwater Study ABSTRACT During the Spring and Summer of 2002, The Oregon Department of Environmental Quality (DEQ) Groundwater Protection Program studied the current magnitude and extent of non-point source pollution of shallow groundwater in the Southern Willamette Valley. The Southern Willamette Valley is considered by DEQ to be a priority area for groundwater assessment and protection for several reasons, including: the severity and extent of nonpoint source groundwater contamination that has been documented in previous studies; the vulnerability of shallow groundwater to impacts from the overlying land uses; the expectation that the population growth in this area will rapidly expand; and that residents in the unincorporated areas of the Southern Willamette Valley will rely on groundwater as their primary drinking water supply. Water-supply data indicate that more than 80% of the groundwater used in the Willamette Valley is pumped from the shallow sand and gravel aquifer. DEQ previously conducted a nitrate groundwater study of the Southern Willamette Valley in 2000-2001. That study confirmed and supplemented data previously collected by DEQ and other agencies characterizing the nitrate contamination of the in shallow groundwater in the alluvial aquifers. Shallow groundwater, defined as less than 75 feet below ground surface for the purposes of this study, was targeted for sampling as this is the resource most likely affected by anthropogenic activities. The 2002 Southern Willamette Valley study focused on the resampling of wells from the SWV 2000-2001 study with nitrate values greater than 7.0 mg/l. The 2002 study included analyzing well water samples for nitrate, phosphate, iron, manganese, arsenic, lead, bacteria, pesticides, caffeine and other water quality parameters. Nitrate values were fairly consistent with previously reported levels. Fifteen (15) different pesticides were detected in the groundwater of the study area; most were detected at very low concentrations. DEQ will use the results of this and previous evaluations to consider groundwater protection strategies, including the potential designation of Groundwater Management Area(s) or Area(s) of Groundwater Concern in the Valley, consistent with the State Statutes ORS 468B.150-188. If such a declaration is realized, then there will be a need to appoint a Lead Agency to develop a groundwater management plan with input from a Groundwater Management Committee comprised of local stakeholders. The primary goals of such management plans include the development and implementation of best management practices to lessen future groundwater contamination and the determination of appropriate means for current protection of public health and the groundwater resource.I. INTRODUCTION This report describes the work completed by the Department of Environmental Quality (DEQ) Groundwater Protection Program during the Spring and Summer of 2002 to study the current magnitude and extent of non-point groundwater pollution of shallow groundwater in the Southern Willamette Valley. The Southern Willamette Valley is considered by DEQ to be a priority area for groundwater assessment and protection for several reasons: including: the severity and extent of nitrate nonpoint source groundwater contamination documented by previous studies; the vulnerability of shallow groundwater to impacts from the overlying land uses; the expectation that the population growth in is area will