Groundwater Quality Studies: U.S. Example (Lapham)
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08/15/14 1 GROUND-WATER QUALITY STUDIES: GROUND-WATER QUALITY STUDIES: U.S. EXAMPLE U.S. EXAMPLE Wayne Lapham, U.S. Geological Survey Wayne Lapham, U.S. Geological Survey
Transcript of Groundwater Quality Studies: U.S. Example (Lapham)
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GROUND-WATER QUALITY STUDIES:GROUND-WATER QUALITY STUDIES: U.S. EXAMPLE U.S. EXAMPLE
Wayne Lapham, U.S. Geological SurveyWayne Lapham, U.S. Geological Survey
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USGS National Water-QualityUSGS National Water-Quality Assessment (NAWQA) Assessment (NAWQA)
Program ExampleProgram Example
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National Water-Quality Assessment National Water-Quality Assessment Program Ground-Water Study Program Ground-Water Study
ObjectivesObjectives
(1)(1) Ground-Water Quality: OccurrenceGround-Water Quality: Occurrence and Distribution. and Distribution.
(2) Trends in Ground-Water Quality.(2) Trends in Ground-Water Quality.
(3) Understanding of Occurrence & (3) Understanding of Occurrence & Distribution and of Trends in Distribution and of Trends in Ground-Water Quality. Ground-Water Quality.
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4 Examples of Occurrence & 4 Examples of Occurrence & Distribution QuestionsDistribution Questions
• What compounds are present & not present in What compounds are present & not present in ground water?ground water?
• Where are compounds found & not found?Where are compounds found & not found?
• At what concentrations & frequencies of At what concentrations & frequencies of detection?detection?
• What types of mixtures of compounds are What types of mixtures of compounds are found?found?
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3 Examples of Trends Questions3 Examples of Trends Questions
• What are the long-term changes and trends in What are the long-term changes and trends in ground-water quality and why?ground-water quality and why?
- What have been the historic trends?What have been the historic trends?
- What are the current trends?What are the current trends?
- What will be future trends under various What will be future trends under various management scenarios ?management scenarios ?
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1 Example of Understanding 1 Example of Understanding QuestionsQuestions
• What are the factors that govern ground-What are the factors that govern ground-water quality?water quality?
• Hydrogeologic factors (confined vs unconfined, Hydrogeologic factors (confined vs unconfined, etc).etc).• Land-use factors (agriculture, urbanization, etc).Land-use factors (agriculture, urbanization, etc).• Natural factors (aquifer mineralogy, etc).Natural factors (aquifer mineralogy, etc).• Geochemical conditions (percent organic carbon, Geochemical conditions (percent organic carbon, dissolved oxygen concentrations, redox, etc).dissolved oxygen concentrations, redox, etc).• Climatic factors (precipitation Climatic factors (precipitation aquifer recharge, aquifer recharge, etc).etc).
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National Water-Quality Assessment National Water-Quality Assessment Program Ground-Water Study Program Ground-Water Study
ApproachApproach
3 Design Concepts used to meet 3 Design Concepts used to meet the 3 objectives at multiple the 3 objectives at multiple scales (Local, Regional & scales (Local, Regional &
National)National)
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3 Design Concepts Applied to NAWQA 3 Design Concepts Applied to NAWQA Water-Quality AssessmentsWater-Quality Assessments
1. Local multiple-scale, nested studies.
2. Consistent design of all local-scale studies.
3. Consistent approaches to conducting local-scale studies.
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Main MessageMain Message
These 3 design concepts (multi-scale, nested
studies, consistent designs, consistent approaches) enable
(1) Local assessments of Ground-Water Quality.
(2) Ability to combine local findings (or data) into Regional & National Water-Quality Assessments.
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What Aquifers To Study & Where?
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Aquifers Studied – Selection CriteriaAquifers Studied – Selection Criteria
• Select from 62 Principal Aquifers.• Select Principal Aquifers with largest withdrawals for drinking-water.• Include representation of all major aquifer lithologies.• Ensure geographic distribution across the U.S.• Include Principal Aquifers with largest areal extents.
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Aquifers Studied – Results of Selection Given Funds Aquifers Studied – Results of Selection Given Funds AvailableAvailable
• About 1/3 of the 62 Principal Aquifers currently being studied.• Provides a framework for regional studies.• Each regional assessment focuses on specific issue(s) of concern.• Local multi-scale, nested studies in each Principal Aquifer.
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3 Design Concepts for Multi-Scale 3 Design Concepts for Multi-Scale QW AssessmentQW Assessment
1. Local multiple-scale, nested studies.
2. Consistent design of local studies.
3. Consistent approaches to conducting local studies.
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Key Design Element: Nested, Multiple-Scale Studies – Example: High Plains aquifer
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Key Design Element: Nested, Multiple-Scale Studies – Example: High Plains aquifer
Each scale of study Each scale of study has a different has a different objective.objective.
Multiple, nested Multiple, nested studies in an aquifer studies in an aquifer provide findings that provide findings that can be collectively can be collectively used to characterize used to characterize and understand and understand Ground-Water Ground-Water Quality in an aquifer.Quality in an aquifer.
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Three design concepts for multi-Three design concepts for multi-scale QW assessmentscale QW assessment
1. Local multiple-scale, nested studies.
2. Consistent design of local studies.
3. Consistent approaches to conducting local studies.
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Consistent Design of Nested, Multiple-Scale Studies in Each Principal Aquifer
Similar studies Similar studies are done in are done in each of the ~20 each of the ~20 Principal Principal Aquifers Aquifers across the U.S.across the U.S.
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Consistent Study DesignsConsistent Study Designs
Local scale: Aquifer studies in about 40 areas (called “study units”).
Regional scale: Summaries in ~20 principal aquifers.
National scale: National summaries using all studies from all Principal Aquifers.
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Three design concepts for multi-Three design concepts for multi-scale QW assessmentscale QW assessment
1. Local multiple-scale, nested studies.
2. Consistent design of local studies.
3. Consistent approaches to conducting local studies.
Consistent approaches to conducting Consistent approaches to conducting these studiesthese studies
• Water-quality constituents measured.
• Sample collection procedures and laboratory analyses.
• Laboratory & field quality assurance.
• Ancillary data collected.
• Data in one common data base.
• Analysis procedures.
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Consistent approachesConsistent approaches
• The same water-quality constituents measured
• For example, NAWQA measures the following in its studies . . .
– Temp, Specific Conductance, Dissolved Oxygen, pH, Turbidity
– Major inorganics– Nutrients– Pesticides– Volatile Orgainc Compounds– Trace Elements– Microbial indicators (coliform, E coli)
Consistent approachesConsistent approaches
• Sample collection procedures are the same
– All sampling crews receive training in QW sampling.
– All sampling crews are taught the same sampling procedures.
– National Field Manual used by all sampling crews.
– QC samples collected when sampling.
Consistent approachesConsistent approaches
• Common Laboratory & Field Quality Assurance are applied
– One laboratory used for analyses.– Same laboratory methods applied.– Standard laboratory Quality Assurance -
Quality Control procedures.– Testing of field office lab performance using
blind sample testing.– Headquarters staff visits to field laboratories.– etc.
Consistent approachesConsistent approaches
• National-scale ancillary data compiled from national coverages
– Population served.– Climatic data.– Soil characteristics.– etc
• Consistent local-scale ancillary data also collected
– Land-use & land-cover around wells.– County-level pesticide and fertilizer application rates.– Septic tank density.– etc
Consistent approachesConsistent approaches
• Data stored in a National Data Base (U.S. Geological Survey National Water Information System)
– QWDATA (QW analyses, etc )
– GROUND-WATER SITE INVENTORY (well-characteristics information, etc )
–WATER USE (water withdrawals, population served, inter-basin water transfers, etc)
Consistent approachesConsistent approaches
• Common analyses and interpretation techniques are applied
– Same approaches to check & verify water-quality data.
– Same approaches to censor water-quality data during analysis & interpretation.
– Similar statistical approaches.
– Similar graphical and tabular displays of data & results.
– Etc.
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SUMMARY: National Water-Quality SUMMARY: National Water-Quality Assessment Program Ground-Water Assessment Program Ground-Water
Study ObjectivesStudy Objectives
(1)(1) Ground-Water Quality: OccurrenceGround-Water Quality: Occurrence and Distribution. and Distribution.
(2) Trends in Ground-Water Quality.(2) Trends in Ground-Water Quality.
(3) Understanding of Occurrence & (3) Understanding of Occurrence & Distribution and of Trends in Distribution and of Trends in Ground-Water Quality. Ground-Water Quality.
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SUMMARY: Main MessageSUMMARY: Main Message
3 design concepts -> multi-scale, nested studies; consistent designs; & consistent approaches
(1) Local assessments of Ground-Water Quality.
(2) Ability to combine local findings (or data) into Regional & National Assessments.
