The Water Along the Beaufort Sea, a broad but shallow continental shelf borders the coast, with depths of 10 m or less found up to 30 km from shore. Amundsen Gulf , a large embayment , is 600 m deep in the centre, with several large bays and relatively little shallow water.
Tides are almost nonexistent.
During this period, the Bathurst Polynya and shore lead system provide areas of open water critical to marine mammals and spring staging birds. The Mackenzie River is the only large North American river emptying into the Arctic and its abundant freshwater output has a profound influence on the productivity of the region. The coast ranges from mostly flat, wet and barely above sea level , to sheer cliffs of 425 m. The Beaufort Sea proper is a drowned coastline with low cliffs that are rapidly eroding. Pingos are characteristic of this area, both on land and below water.