Running Water Day 2

Objective By the end of today, I will be able to: – Evaluate how materials are _____________in a stream and how they are _______________. – Predict why _____________happen and some methods of flood control.

Key Points The ability of a stream to erode and transport material depends largely on its velocity. Most streams carry the largest part of their load in suspension. The suspended load of a stream usually consists of find sand, silt, and clay-sized particles. A depositional feature that forms where a stream enters a lake or ocean is a delta. In a stream channel, the heaviest particles are deposited first. - gravel, then sand, then clay. Occasionally, deposition causes the main channel of a stream to divide into smaller channels called distributaries. Major causes of floods include: rapid snow melt, heavy rain, decreased capacity of stream channels. Flood control methods include artificial levees, sandbags and dams.

Stream Load The ability of a stream to ________and transport material depends largely on its _____________. – What is velocity? – velocity = ________________the stream covers / amount of ________ What type of materials do streams carry? – _________, dirt, clay, _________, salt, __________… How do streams carry material?

Streams  Streams generally erode their channels, lifting loose particles by _____________, grinding, and by ________________soluble material.  When the flow is turbulent enough, it can dislodge loose particles from the channel and ___________them into the moving ________.  The stronger the current, the more erosional power and more effectively water will pick up the _________________.

Streams Sediment is transported by streams in 3 ways… 1. In solution (____________load) 2. In suspension (________________load) 3. Scooting or rolling along the bottom (__________load)

Streams Sediment is transported by streams in 3 ways… 1.In solution (dissolved load) – What type of materials would dissolve in a stream? ________and other ________materials – How do these materials enter the stream? Through _____________and _____________rock along the stream’s course

Streams Sediment is transported by streams in 3 ways… 2. In suspension (suspended load) – What does it mean if something is suspended? It’s _____________! – What types of materials are suspended? Usually just ____________________ – A suspended load is where streams carry the _________part of their load

Streams Sediment is transported by streams in 3 ways… 3. ____________or rolling along the bottom (bed load) – What type of material moves in the bed load? Materials ___________to be carried in suspension – The bed load moves only when the force of the water is large enough to move the larger particles

Depositional Features When the materials carried in a stream __________ _____________they are DEPOSITED. This creates several features that shape the landscape around the stream including: – _____________________ – ________________ – Natural _________________

Depositional Features Distributaries ____________in the main channel can sometimes cause the stream to _________into smaller channels called distributaries.

Depositional Features In your notes label the head and mouth of this river and place a “D” next to the distributaries D D D D D D Head Mouth

Depositional Features Delta – an ___________________________ formed where a stream enters a lake or ocean. Why does the sediment build up (accumulate) when a stream reaches a lake? – Because the ________________________! – The ___________can no longer carry sediment!

Delta What happens to the sediments when the stream reaches the ocean? _______________

Depositional Features Natural Levees – a natural build up of sediments that run ____________to a stream. They form after the stream __________, leaving sediment behind. This can naturally _______________future flooding

Flooding What are some things that cause flooding? – Heavy ______________ – ____________________________ Why are floods bad? – They cause ___________________ – They can come without warning (______________) – They can ____________people – ________________a lot of money What are some floods that you have heard of, why were they dangerous? – Discuss with a partner

Flooding There are several methods used to help prevent flooding: – Artificial ______________ – Create _______________ – ______________________ – Limit ____________around areas known to flood Mississippi Flooding – What caused the flood? – What caused the most damage during the Flood?

Check In Questions 1.The ability of a stream to erode and transport material depends on what? 2.Most streams carry most of their load in what way? 3.What is a delta in your own words? Why do they form? 4.What is a distributary? How do they change the course of a stream? 5.Why do floods form? 6.How could we prevent extreme flood damage, like during Hurricane Katrina?