I created a post about Grant's Canal several years ago. I got to visit the last remaining part in April 2014. The canal is just off I-20 on the Louisiana side of the Mississippi across from Vicksburg, Mississippi. The canal had plenty of water seeing that it had rained the day before. Some photos I have seen elsewhere of the canal show it dry. If you make it to Vicksburg, be sure to visit Vicksburg National Park, the National Cemetery, and the amazing USS Cairo display, in addition to the canal.