A final version of CT DOT's MS4 General Permit was released in May 2018 and is posted on DEEP's stormwater page. The DOT permit goes into effect July 1, 2019.
CT DOT presented a webinar on their new permit which was recorded and is now posted on the UConn CLEAR website webinar library. And a side note: CT DOT also created an email address that municipalities can use to ask questions about the CT DOT permit, it's DOT.MS4@ct.gov.
The MS4 permit generally applies town (or institution) wide but certain requirements focus on what are deemed "priority areas". These include areas that meet any of the following three conditions: in the Census Urbanized Area, catchments with >11% DCIA, or catchments that discharge to impaired waters.
Below is a screen shot from the MS4 map viewer looking at Naugatuck with the Urbanized area (gray) layer, the IC by Basin (yellow) layer, and the 2016 stormwater impaired waterbodies (red) layer(s) turned on. We can get a general sense that Naugatuck's priority areas include most of the town except the light gray area to the west. Notice that there are a few yellow basins that go beyond the dark gray urbanized area. Because the yellow basins are areas with >11% impervious area - not necessarily Directly Connected Impervious Area - they may be less than 11% DCIA and thus not a part of the prioirity area. Naugatuck could use one of our approaches to estimate DCIA in those basins to determine their %DCIA.
We also made a short video explaining priority areas here:
There doesn't seem to be one typical person in town who fills this role. The list below gives a sense of the variety of positions many CT towns have designated as their ordinance enforcement agent. Most ordinances also say that the authorized enforcement agent may identify a designee in writing.
There was confusion about whether the 'fee in lieu of' and off-site mitigation requirements on pages 28-20 of the permit were to be implemented by 2019 but good news! The deadline is July 2021 for existing (and July 2022 for new permittees) - which aligns with the deadline to establish the corresponding legal authority. We are planning to develop guidance to help out with this aspect of the permit.
There are two monitoring requirements under the new permit. The first deals with monitoring outfalls that discharge directly to stormwater impaired waters. These are the purple and red waterbodies on the MS4 map viewer.
The second monitoring requirement is related to the illicit discharge detection and elimination (IDDE) program.
For more help understanding the permit monitoring requirements, check out the monitoring page.