Water Quality Division, Stormwater Section
103 South Main Street, Building 10 North
Waterbury, VT 05671-0408
Vermont Stormwater MSGP 3-9003, NPDES Number VTR050001
6.1.3 Measurable Storm Events
All required monitoring must be performed on a storm event that results in an actual discharge from your site (measurable storm event) that follows the preceding measurable storm event by at least 72 hours (3 days). The 72-hour (3-day) storm interval does not apply if you are able to document that less than a 72-hour (3-day) interval is representative for local storm events during the sampling period. In the case of snowmelt, the monitoring must be performed at a time when a measurable discharge occurs at your site. For each monitoring event, except snowmelt monitoring, you must identify the date and duration (in hours) of the rainfall event, rainfall total (in inches) for that rainfall event, and time (in days) since the previous measurable storm event. For snowmelt monitoring, you must identify the date of the sampling event.
Magnitude: results in actual discharge
Interval Between Storms: at least 72 hours