@Wildflower :
(Check out Bob Rehak's reports.) The same thing happened at the marina/boat launching area at the park at the end of Woodland Hills drive. It was totally unusable prior to dredging. Haven't been down to see that area recently.
Briefly, the sand companies along the San Jacinto River towards Conroe dredge. But they aren't particularly good about maintaining their piles/discards according to regulations. (No, it not only their escaping sand but also some others that feed into the San Jac west of 59)