Virtually every existing stream will be overflowing its banks, so yeah - new rivers will have to form: the water has to get downhill somehow. This is going to be epic-bad level.
I have family in Sealy. We used to play the Stephen Austin Golf Course there. The Brazos has rearranged the Golf Course a few times over the years. Hate to think what may happen with this storm.
The course was covered with pecan trees. My father-in-law had a double sided wedge. He could hit that club 150 yards, 3 feet off the ground both left and right handed. Best club ever made for a course on a pecan grove. Good memories!