At high elevation, springs and runoff first gather into a channel that begins a river's flow. What part of the river system is this?

A smaller stream joins a larger river partway along its course and adds all of its water to it. What is the smaller stream called?

Two streams meet at one point and continue as a single larger channel. What is the meeting point called?

A river reaches the coast and empties its water into the sea. What part of the river is located there?

Every hillside and creek in an area sends runoff into the same main river. What is that whole drained area called?

A ridge separates two river systems, so rain on one side flows to one river and rain on the other side flows to another. What is the ridge called?

Near a delta, a branch leaves the main river channel and carries water away toward the sea. What is that branch called?

A steep mountain stream reaches a flat plain, slows suddenly, and drops gravel and sand in a spreading deposit at the foot of the slope. What landform forms there?

On flat lowland, a river overflows its banks again and again, spreading layers of silt across the wide, flat land beside the channel. What landform is built there?

Repeated floods drop the coarsest sediment right next to a river channel, raising low ridges along both banks. What are these ridges?

On the inside of a river bend, slower water drops sand and gravel in a crescent-shaped deposit. What landform is this?

A river enters a quiet lake or sea, slows, and spreads sediment into a broad fan of new land at its mouth. What landform is this?

A wide river loop is cut off from the main channel after the river takes a shorter path. What curved body of water remains?

Waves undercut the base of a steep rocky coast until blocks collapse, leaving a tall, nearly vertical wall. What landform is this?

As waves erode a sea cliff backward, they leave a flat rock bench that is visible at low tide. What is this bench called?

Waves strike cracks in a headland and widen them into a hollow chamber in the rock. What coastal landform is this?

Waves erode a headland from both sides until a hole cuts all the way through the rock. What landform has formed?

After a sea arch collapses, an isolated pillar of rock remains offshore. What is the remaining pillar called?

Longshore drift carries sand along a coast and deposits it as a narrow ridge projecting into a bay, attached to land at one end. What is this?

Near the coast, a river's fresh water mixes with salty tidal seawater in a partly enclosed body of water. What is this mixing zone called?

Rain falling just west of the Continental Divide in Montana runs into streams of the Columbia River system. Which ocean does that water drain to?

A stream keeps flowing all year long because groundwater keeps feeding it even in dry seasons. What type of stream is this?

Utah's Great Salt Lake sits at the bottom of a closed basin. Why is its water so much saltier than the rivers that feed it?

Storm drains on a neighborhood slope carry runoff into a creek, then a river, then the sea. In watershed terms, the neighborhood drains into what?

A river flows over a sudden, steep drop in its streambed, where the channel plunges to a lower level. What is this steep drop called?