I haven't seen Denton Creek, but I did head over to several other spots on Grapevine yesterday to check it out. Twin Coves is totally closed - gate is locked. Murrell Park was still technically open but the attendant said it would completely close by end of Saturday. The boat ramp parking lot was completely under water and the water line was not that far from the guard shack! Over by oak Grove all 3 boat ramps had locked gates and the parking lots were completely under water. Several Oak Grove soccer fields are flooded. The attendant at Murrell said "the lake is closed by the Corps". I'm not exactly sure what that means but I am guessing no boat traffic for sure.
Lake Lewisville falls under the Ft. Worth District Trinity River Basin area for the Army Corps of Engineers - so they will generally have a play into whether or not it remains opened/closed. It is over 10 foot high now, so they COULD have made that call, but the attendant could have his information mixed up. Wouldn't surprise me, though, Lewisville has flooded over some roads, and even has certain boat dock garages that aren't accessible anymore.
EDIT: Just looked up the water information and believe they have it stated as 10.15 ft above 522. 532 is the flood pool, and as of today Lewisville has gone above 532.