The Chops are a narrow, 600 yard wide, cleft at the point where water flows out of Merrymeeting Bay and into the lower Kennebec on its way to the ocean. Carved out by a glacier 10,000 years ago, it was called 'Kebec' or 'Spot that Seems Closed' by the Indians. All the Bay waters (from 6 rivers draining +-2/5 of Maine) have to flow through the Chops. Every 12 hours the ocean tide comes into the Lower Kennebec and holds back water flowing out through the Chops. Fresh water flowing down, slows and actually is forced back upstream, raising the water level in the Bay +- 5 feet. This tidal influence is felt all the way to Augusta. Little salt water penetrates into the Bay itself.
"The Chops, at the outlet of Merrymeeting Bay, is a drowned waterfall. Our best guess, based on the rate of coastal emergence, is that it was drowned about 5000 years ago. Before that time the Chops would have been a massive waterfall..." Kennebec River Resource Management Plan: Maine State Planning Office, 1993