Updated: Mar 31
We just got done with our first big rain event of the season. Depending on where you're located you might've experienced a qualifying rain event, one that is predicted to produce 0.5" of rain or more, separated by 48 hours of no rain.
So, you're probably getting all kinds of reports from us or your SWPPP inspector. It can be a lot. Below, we've noted the kinds of reports that you may be seeing in your inbox, as well as why you've received them. Hopefully, this can help you figure out what's going on.
Some terms you need to know...
Qualifying Rain Event - Storm that produces 0.5" or more of rain, separated by 48 hours of no rain
Forecasted Storm Event - Storm that is forecasted to produce at least 0.10" inch of precipitation within a 24-hour period
This includes both an inspection and a report. It's required within 48 hours of a forecasted qualifying rain event (a storm that produces 0.5 inches or more). This inspection and report will list out actions that should be taken prior to the storm to button up your site and prevent polluted discharges.
The Caltrans equivalent is the CEM 2030 Pre-Storm Report and CEM 2035 Corrective Actions, this is required within 48 hours prior to a forecasted storm event, which is one that is forecasted to produce 0.10 inch of rain within a 24-hour period.
Note: it's a really good idea in the rainy season (which technically starts on October 15th in Northern California) to only keep active what you can quickly button up before a rain event.
Some of my personal go-to options to stabilize disturbed soil areas are to use some form of cover on the soil (e.g. hydraulic mulch, hydroseed, rolled erosion control product, plastic cover for smaller areas) and sediment controls (e.g. silt fence, compost socks, fiber rolls).
But, if and whenever possible, try to see if you can implement final stabilization to save time, energy, and money.
Rain Event Action Plan (REAP)
Required to have on-site 24 hours prior to the rain event when there is a 50% chance of any rain for Risk Level 2 and 3 projects only. It's basically a Pre-Storm with a little more *bang*. Long story short, shut down your operations as much as you can before and during a big rain. It's just going to save you a headache by staying out of the mud.
Scroll to the comments and corrective actions section for the meat of the REAP. Use this report and your Pre-Storm report to get ready for rain.
The Caltrans equivalent is the CEM2045 REAP and is required for a 50% chance of any rain within 48 hours prior to the rain event.
An inspection and report are to be conducted every day during an extended rain event for both Caltrans and CASQA projects. It's a fun day for us - we get to play in the rain
The Caltrans equivalent is the CEM 2030 During Storm Report.
Note: it's a good idea to keep extra BMPs on-hand for emergencies, like extra plastic (preferably the Visqueen), gravel bags, and fiber roll
If you have a Risk Level 2 or 3, your site is required to have Stormwater Sampling. If the storm is a qualifying rain event and produces over 0.5" of rain we have to take samples of stormwater runoff leaving the job site. We have trained professionals to learn where and how to take these samples, and how to sample for run-on to determine the cause of an exceedance if there is one.
The Caltrans equivalent is the CEM 2052 Sampling Form and is required whenever sampling is performed.
Required for all sites if the storm was a qualifying rain event, and is required to be conducted within 48 hours after the commencement of the storm. This will outline any clean-up or repairs needed after rain.
The Caltrans equivalent is the CEM 2030 Post-Storm Inspection and Report.
We have a couple of other forms that you hopefully won't have to see, like the NAL Exceedance Report or a Notice of Discharge. These reports require their own explanation - if you're interested in a blog post on this topic drop us a comment below!
This was a quick and dirty explanation of our most basic Storm Event Forms. If you need professional Stormwater Manager's and Inspectors, reach out to our team at firstname.lastname@example.org or calling (707) 693-1926.