Author Question: Why are floods so important in making floodplain landforms? What will be an ideal ... (Read 41 times)

MirandaLo · **on:** Jul 13, 2018

Why are floods so important in making floodplain landforms?

What will be an ideal response?

Question 2

Explain how rivers construct deltas. Then, speculate as to why the mighty St. Lawrence Riverdraining the Great Lakesdoes not have a delta.

What will be an ideal response?

nyrave · **Reply #1 on:** Jul 13, 2018

Answer to Question 1

Answer: These landforms are overwhelmingly depositional. The material that made these landforms has come as load from the streams. The load is deposited on the floodplain when water comes overbank and has to slow down and loses some competence.

Answer to Question 2

Answer: Rivers reach base level and lose some of their competence because of slower flow. Some sediments must be dropped. If there are enough sediments dropped then then main channel starts to clog and the river forms many channels in a delta-shape as it fans out over the dropped sediments. The St. Lawrence has not delta because its sediment load is very small compared to its dischargematerials do not need to be dropped.