DC Water: "we are sending a 2nd round of pre-construction documents to residents who have not responded to the 1st mailing"

See this tweet exchange:
 

DC Water ‏@dcwater 1h

@bloomingdame Correct.

Bloomingdame ‏@bloomingdame 1h

@dcwater Thanks! Figured that was what it was. So, if you have first letter, you don't need to rush to PO to get this letter.

 
DC Water ‏@dcwater 1h

.@bloomingdame If you get the second packet and you have already responded, please disregard the second one. #1stStreetTunnel

DC Water ‏@dcwater 1h

.@bloomingdame We are sending a 2nd round of pre-construction documents to residents who have not responded to the first mailing.

Bloomingdame ‏@bloomingdame 1h

@dcwater Are you resending the survey letters, or is there some new information in the mail?