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Learning CenterField methods chapterAssess Lake and Reservoir Source-Water Susceptibility and Design Intake Monitoring
Evidence method · Source-water susceptibility and intake monitoring

Assess Lake and Reservoir Source-Water Susceptibility and Design Intake Monitoring

Build a source-pathway-receptor susceptibility record and a decision-specific monitoring design while preserving utility, authority, security, laboratory, and inference boundaries.

For
Drinking-water utilities, source-water coordinators, Tribes, primacy agencies, watershed organizations, public-health and emergency partners, lake managers, laboratories, consultants, and community monitoring programs
Reading time
34 minutes
Reviewed
Next review
Direct answer

What to do first

Start with the supplying system, decision, source-water use, responsible utility and authorities, evidence class, and protected information. Delineate the protection area with documented hydrology, tributaries, intake zones, travel assumptions, uncertainty, and version. Inventory potential contaminant sources without assigning blame; proximity is not hydrologic connection, susceptibility is not contamination, and DWMAPS or another portal is not a complete current inventory. Design baseline, sentinel, event, tributary, lake, depth, and intake-zone roles around the decision rather than a universal panel or station. Use authorized methods, qualified laboratories, custody, QA, reporting limits, validation, and versioned provenance. A non-detect does not prove absence, untargeted contaminants cannot be declared absent, ambient criteria are not MCLs, CWA impairment is not an SDWA violation, and a source-water result does not authorize utility action. Predefine utility, primacy, emergency, public-health, security, and public-release handoffs.

Use this guide to
  • Define a bounded source-water decision
  • Preserve source-to-tap and authority boundaries
  • Build a versioned protection-area model
  • Separate potential sources from releases and blame
  • Design reproducible monitoring and QA
  • Predefine secure authority handoffs

1. Define the decision, system, authority, source, and use

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Name the decision owner, supplying system, source-water use, jurisdiction, evidence class, and prohibited inference before selecting measurements. Source-water monitoring does not determine tap safety or authorize utility operations.

Sources: [2], [1]

2. Preserve source-to-tap and regulatory boundaries

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Name the decision owner, supplying system, source-water use, jurisdiction, evidence class, and prohibited inference before selecting measurements. Source-water monitoring does not determine tap safety or authorize utility operations.

Sources: [2], [1]

3. Delineate the source-water protection area

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Use current assessment, delineation, watershed, intake-zone, tributary, travel-time, land-use, and operational evidence. Record assumptions and uncertainty; proximity is not hydrologic connection, a potential source is not a release, and susceptibility is not contamination.

Sources: [11], [19]

4. Model lake, tributary, intake-zone, and travel-time hydrology

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Use current assessment, delineation, watershed, intake-zone, tributary, travel-time, land-use, and operational evidence. Record assumptions and uncertainty; proximity is not hydrologic connection, a potential source is not a release, and susceptibility is not contamination.

Sources: [11], [19]

5. Inventory potential contaminant sources without assigning blame

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Preserve portal provenance and gaps. DWMAPS is not a complete current inventory, a map layer does not prove a current facility, and database absence does not prove compliance.

Sources: [10], [21], [15]

6. Evaluate source-pathway-receptor susceptibility

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Preserve portal provenance and gaps. DWMAPS is not a complete current inventory, a map layer does not prove a current facility, and database absence does not prove compliance.

Sources: [10], [21], [15]

7. Audit DWMAPS, WQP, ATTAINS, USGS, state, Tribal, and utility provenance

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Assign baseline, sentinel, event, tributary, lake, depth, intake-zone, and existing-data roles to the stated decision. No universal contaminant panel, station, depth, interval, or season represents every system.

Sources: [20], [12]

8. Define baseline, sentinel, event, tributary, lake, and intake roles

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Assign baseline, sentinel, event, tributary, lake, depth, intake-zone, and existing-data roles to the stated decision. No universal contaminant panel, station, depth, interval, or season represents every system.

Sources: [20], [12]

9. Select contaminant groups and indicators without a universal panel

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Use authorized methods, qualified laboratories, custody, reporting limits, blanks, duplicates, calibration, validation, and a QAPP appropriate to the decision. A non-detect does not prove absence and untargeted contaminants cannot be declared absent.

Sources: [18], [20]

10. Design spatial, temporal, depth, event, and operating-state coverage

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Use authorized methods, qualified laboratories, custody, reporting limits, blanks, duplicates, calibration, validation, and a QAPP appropriate to the decision. A non-detect does not prove absence and untargeted contaminants cannot be declared absent.

Sources: [18], [20]

11. Control methods, laboratories, custody, QA, and validation

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Predefine utility, primacy, environmental, emergency, public-health, and public-communication handoffs. Ambient criteria are not MCLs, CWA impairment is not an SDWA violation, and a source result does not authorize intake action.

Sources: [17], [9]

12. Separate screening, detections, non-detects, and criteria

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Predefine utility, primacy, environmental, emergency, public-health, and public-communication handoffs. Ambient criteria are not MCLs, CWA impairment is not an SDWA violation, and a source result does not authorize intake action.

Sources: [17], [9]

13. Predefine utility, primacy, emergency, and public handoffs

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Release versioned evidence with source, method, scope, qualifiers, security classification, reviewer, correction path, and supersession. Generalize sensitive intake and infrastructure information.

Sources: [6], [8]

14. Release and update versioned evidence

Build one attributable monitoring-design decision without crossing utility, authority, or inference boundaries.

Release versioned evidence with source, method, scope, qualifiers, security classification, reviewer, correction path, and supersession. Generalize sensitive intake and infrastructure information.

Sources: [6], [8]

Evidence base

Sources and review notes

Educational source-water protection, evidence-control, and preparedness guidance only. It is not a tap-water safety determination, drinking-water advisory, contaminant identification, regulatory finding, emergency-response plan, treatment instruction, intake operating instruction, permit, funding award, or authorization. Current utility, primacy-agency, public-health, emergency, Tribal, federal, state, territorial, local, landowner, laboratory, security, privacy, access, sampling, and public-communication requirements control.

  1. Basic Information about Source Water ProtectionU.S. Environmental Protection Agency · agency guidance
  2. Assess, Plan and Protect Source WaterU.S. Environmental Protection Agency · agency guidance
  3. Source Water Protection PlanningU.S. Environmental Protection Agency · agency guidance
  4. Source Water Protection PracticesU.S. Environmental Protection Agency · agency guidance
  5. Evaluate Progress Toward Source Water Protection GoalsU.S. Environmental Protection Agency · agency guidance
  6. Common ConsiderationsU.S. Environmental Protection Agency · agency guidance
  7. Preparing for EmergenciesU.S. Environmental Protection Agency · agency guidance
  8. Incident Action Checklist: Source Water ContaminationU.S. Environmental Protection Agency · reference
  9. Primacy Agency Drinking Water DataU.S. Environmental Protection Agency · reference
  10. DWMAPS User GuideU.S. Environmental Protection Agency · reference
  11. Resources for Source Water AssessmentsU.S. Environmental Protection Agency · reference
  12. Types of Drinking Water ContaminantsU.S. Environmental Protection Agency · reference
  13. Tribal Governments' Role in Safe Drinking Water in Indian CountryU.S. Environmental Protection Agency · agency guidance
  14. How's My WaterwayU.S. Environmental Protection Agency · reference
  15. Assessment, Total Maximum Daily Load Tracking and Implementation SystemU.S. Environmental Protection Agency · reference
  16. Water Decontamination Frequently Asked Questions for CustomersU.S. Environmental Protection Agency · agency guidance
  17. Long Term 2 Enhanced Surface Water Treatment Rule DocumentsU.S. Environmental Protection Agency · reference
  18. Quality Assurance Project Plan StandardU.S. Environmental Protection Agency · field protocol
  19. Drinking Water and Source Water ResearchU.S. Geological Survey · reference
  20. Lakes and Reservoirs: Guidelines for Study Design and SamplingU.S. Geological Survey · field protocol
  21. Water Quality PortalNational Water Quality Monitoring Council · reference