Industrial Stormwater Program
520 Lafayette Road North
Saint Paul, MN 55155-4194
Minnesota Pollution Control Agency General Permit Authorization to Discharge Stormwater Associated with Industrial Activity Under the National Pollutant Discharge Elimination System/State Disposal System Permit Program.
g. Samples shall be collected from a measurable runoff event (precipitation or snow melt) at a benchmark monitoring location, provided that the interval since the preceding measurable runoff event is at least 72 hours.
If it is not possible to collect the sample within the first 30 minutes of a measurable runoff event at the benchmark monitoring location, the sample shall be collected as soon as practicable after the first 30 minutes and documentation must be included with the Stormwater Monitoring Report that explains why it was not possible to collect samples within the first 30 minutes of a measurable runoff event.
Magnitude: measurable runoff
Interval Between Storms: at least 72 hours