Stormwater runoff from industrial facilities can carry pollutants that negatively impact water quality. Compliance with stormwater regulations, such as the Multi-Sector General Permit (MSGP), often requires regular stormwater sampling and reporting. This guide provides a comprehensive overview of how to do stormwater sampling for industrial facilities, covering essential aspects from planning to reporting.
Understanding Stormwater Sampling Requirements
Before initiating any sampling activities, it’s crucial to understand the specific requirements of your permit. This includes identifying the pollutants you need to monitor, the sampling frequency, and the reporting deadlines. The MSGP, for example, often requires monitoring for:
- Hazardous Metals: Required annually unless a waiver is obtained.
- Benchmark Monitoring: Required semi-annually for certain SIC codes.
- Federal Effluent Limits: Required annually for specific activities.
- Impaired Waterbody Monitoring: Required annually if the facility discharges a Pollutant of Concern (POC) into a receiving waterbody.
Alt: Example of stormwater runoff sampling at an industrial facility, showing the collection of a water sample from a discharge point.
Planning Your Stormwater Sampling
Effective stormwater sampling starts with careful planning. Consider the following factors:
- Identify Sampling Locations: Determine the appropriate sampling points based on your permit and facility layout. These are typically discharge points where stormwater leaves your property.
- Develop a Sampling Schedule: Create a schedule that aligns with the required sampling frequency and reporting deadlines.
- Select a Qualified Sampler: Ensure that the person responsible for collecting samples is properly trained and knowledgeable about sampling techniques.
- Gather Necessary Equipment: Assemble all the equipment you’ll need for sampling, including sample containers, preservatives, a cooler with ice, and a field logbook.
- Prepare a Stormwater Pollution Prevention Plan (SWP3): Your SWP3 should detail all aspects of your stormwater management program, including sampling procedures.
Step-by-Step Guide to Stormwater Sampling
Follow these steps to ensure accurate and representative stormwater samples:
- Check Weather Conditions: Avoid sampling during or immediately after a significant rainfall event, as this can dilute the sample and skew results.
- Prepare Sampling Equipment: Clean and inspect all sampling equipment to prevent contamination.
- Collect Samples:
- Grab Sample: Collect a single sample at a specific time. This is the most common type of stormwater sample.
- Composite Sample: Collect multiple samples over a period of time and combine them into a single sample. This provides a more representative sample of the overall stormwater discharge.
- Fill Sample Containers: Carefully fill the sample containers, leaving some headspace to allow for expansion.
- Add Preservatives: Add any required preservatives to the sample containers to prevent degradation of the pollutants of concern.
- Label Sample Containers: Clearly label each sample container with the date, time, location, and any other relevant information.
- Maintain Chain of Custody: Complete a chain of custody form to track the samples from collection to analysis.
- Store and Transport Samples: Store the samples in a cooler with ice to maintain a temperature of 4°C and transport them to a certified laboratory as soon as possible.
Alt: Typical stormwater sampling equipment, including sample bottles, cooler, and documentation.
Analyzing and Reporting Stormwater Sampling Results
Once the laboratory has analyzed the samples, you’ll receive a report with the results. Review the report carefully to ensure that the data is accurate and complete.
- Compare Results to Permit Limits: Compare the analytical results to the effluent limitations and benchmark values specified in your permit.
- Identify Exceedances: If any of the results exceed the permit limits, take corrective action to address the source of the pollution.
- Submit Your Report: Submit your stormwater discharge monitoring report (DMR) to the appropriate regulatory agency by the specified deadline. In many cases, this is done electronically using systems like NetDMR.
Electronic Reporting with NetDMR
Many regulatory agencies, including the TCEQ, require electronic reporting of stormwater sampling data through systems like NetDMR. Here’s a brief overview of the process:
- Create a NetDMR Account: Register for a NetDMR account and select the appropriate role (Permittee with Signature, Permittee without Signature, or Data Provider).
- Locate Your DMRs: Find your MSGP DMRs in the NetDMR system. These may be Scheduled (S) or Unscheduled (U) depending on your permit requirements.
- Enter Sampling Data: Enter the sampling data for each parameter listed on the DMR. Be sure to include the Outfall ID and Season ID.
- Submit Your DMR: Review your DMR carefully and submit it electronically by the deadline.
Common Issues and Troubleshooting
- Facilities Reporting Benchmark Values but Not Hazardous Metals: If you submitted a waiver for hazardous metals or had no exceedances, report a No Data Indicator (NODI) code “9” for the hazardous metals parameters.
- Facilities Only Required to Sample for Hazardous Metals: If you are only required to sample for hazardous metals and had no exceedances or submitted a waiver, do not report in NetDMR.
- Facilities with Substantially Similar Outfalls: Only report in NetDMR for one representative outfall and use NODI Code 9 to report for the other outfalls.
Conclusion
Stormwater sampling is a critical component of environmental compliance for industrial facilities. By following the steps outlined in this guide, you can ensure that your sampling program is accurate, effective, and meets all regulatory requirements. Remember to consult your permit and local regulations for specific guidance, and don’t hesitate to seek assistance from environmental professionals if needed.
