This specific stream information is taken from FERC’s FEIS
See printable pdf here: Specific Stream Info from FEIS
There are 45 Trout (T) and Trout Spawning (TS) streams along the pipeline route. However, the proposed route would cross them 84 times.
T and TS streams are sensitive and get special protections. This is because trout can only survive in clear cold waters with high levels of dissolved oxygen.
DEC classifies streams by alphabetical codes.