Quarterly Stormwater Monitoring Deadline Approaching

School is back in session, and we already have some homework due. The cutoff date for quarterly stormwater visual monitoring for Q3 is September 30. With limited rain events on the horizon, these last few weeks are crucial to get monitoring completed before Q4 kicks off on October 1. 

Permit Requirements

This deadline affects facilities that are covered under the New York State Department of Environmental Conservation (NYSDEC) Multi-Sector General Permit (MSGP) for Stormwater Discharges Associated with Industrial Activity (GP-0-23-001), as well as facilities that are covered under individual State Pollutant Discharge Elimination System (SPDES) permits that include conditions related to stormwater discharges.

A visual monitoring report and routine quarterly inspection report must be generated each quarter to comply with the permit requirements. In some cases, quarterly stormwater sampling is also required. The required sampling parameters vary from site to site, and depend on the industrial sector that the site falls under.

Quarterly Monitoring Process

The quarterly visual monitoring process must be done during a qualifying storm event, which is defined as at least 0.1 inches of precipitation. It includes a walking inspection of the site to make sure that all stormwater Best Management Practices (BMPs) are in working order and that no obvious sources of pollution are present (oil drums knocked over, gasoline leaking from a tank, etc.), as well as a visual inspection of the runoff at each outfall, checking for qualities such as the following:

• Turbidity (clear, cloudy, etc.)
• Noticeable odor
• Presence/absence of an oil “sheen”
• Debris or particulate matter

If the visual inspection indicates the presence of stormwater pollution, corrective actions must be taken and another inspection must be done to determine their effectiveness. Lab testing of samples for quarterly monitoring is not required unless previously stated in the facility’s MSGP or SPDES permit.

How Can Walden Help?

The scientists and engineers at Walden have been assisting clients with stormwater needs for nearly 30 years. Our staff are well versed and practiced in the application and upkeep of Stormwater Pollution Prevention Plans (SWPPPs), SPDES permits, and MSGPs. Contact us today at 516-980-5508 to speak to a specialist about tackling the stormwater requirements that apply to your facility.