The lock is down with limited openings. Valve failure limits them to periods when the water levels are the same on both sides of the lock. Even though it is late in the season Elizabeth City is going to be full.

http://www.nao.usace.army.mil/Media/NewsStories/tabid/3058/Article/19720/great-bridge-lock-down-repairs-underway.aspx

http://cruisersnet.net/great-bridge-va-lock-closed-as-of-mid-day-110513/