Preserve the source.
Retain the underlying documents and distinguish reported application locations from independently verified boundaries.
Records · Fieldwork · Laboratory evidence
From the treatment site
to the water below.
How we connect application records, watershed mapping, field sampling, laboratory results, and source investigations.
From application to evidence
A connected investigation.
Each step informs the next: records guide sampling, samples guide analysis, and the combined evidence guides the source investigation.
Document the application.
Identify the forestry project, treatment boundaries, dates, products, methods, landowner, and applicator. Preserve the original reports and notices.
Map the water below.
Connect treatment areas with potential drainage pathways, streams, springs, ponds, and suitable comparison locations. Account for access and terrain.
Plan the sampling.
Use application timing and site conditions to plan baseline and follow-up monitoring where feasible, including relevant rainfall, runoff, and snowmelt periods.
Test for what was used.
Select laboratory analyses with the documented products and active ingredients in mind. Record the methods, sample handling, and laboratory reporting limits.
Investigate the source.
Evaluate the application records alongside the locations, timing, chemical behavior, weather, and sampling results. Examine other plausible sources.
Publish the evidence.
Present the supporting records and findings with a clear explanation of the methods, limitations, and conclusions.
Fieldwork with a purpose
Test below
the project.
Our monitoring approach starts with a site-specific question. We seek sampling locations that can help distinguish conditions above and below a treatment area, rather than selecting a water sample in isolation.
Sampling plans may include surface water, springs, sediment, or other media where relevant to the investigation. The sample type, timing, supplies, handling, and laboratory method must fit the question being asked.
Field participation is coordinated. Sampling work is planned around training, safe and authorized access, and appropriate laboratory requirements. This website is not a substitute for a field sampling plan.
A quality record
The sample and its context.
- Where and when: sample location, collection time, relevant application dates, and site conditions.
- What was collected: sample type, identifier, handling information, and the analyses requested.
- What the laboratory reported: results, methods, reporting limits, and qualifiers.
- What supports the interpretation: comparison locations, weather, maps, and other possible sources.
Our evidence standard
A detection starts
an investigation.
Explain the connection.
Show how timing, geography, chemical behavior, and sampling results support—or limit—a source interpretation. A detection alone does not establish responsibility.
Show the limitations.
Publish the methods and relevant uncertainty alongside the findings, including alternative explanations and questions for further investigation.
Know what was applied.
The application database supports the investigation; it is not the endpoint.
The complete monitoring cycle
Plan the collection.
Follow the evidence.
Water and creek-bed sediment
Before fall rain and spring snowmelt, write a plan specifying where to go, what to collect and which laboratory tests the PURs support. Maps, coordinates and access routes let volunteers and investigators return to the same points.
Reach remote drainages
Experienced volunteers will collect from remote creeks and runoff pathways beyond maintained roads, with access arranged as needed. The laboratory sets containers, handling, preservation and shipping requirements.
Missing application reports
Request the PUR for reported spraying. If no report is on record, investigate the application and initially target hexazinone, indaziflam and 2,4-D using suitable laboratory methods. Disclose the missing record and the basis for test selection.
Complaints are the beginning of follow-up
When findings warrant complaints, provide the county Agricultural Commissioner, DPR and regional Water Board with the PURs, sampling plan, collection coordinates, laboratory reports, photographs and field records. Guide investigators to the locations to confirm the findings. Obtain investigation records and publish findings, decisions, corrective measures, unanswered questions and delays.
Publish detections and non-detections with sample type, collection date, location and reporting limits. A detection warrants investigation; it does not automatically establish a particular source, legal violation or health effect.