Term
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Definition
| The single path of deepest points running down a stream. |
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Term
| What are the 4 parts of a stream? |
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Definition
| run, riffle, pool, meander. |
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Term
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Definition
| A straight-away on a river. |
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Term
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Definition
| when water riffles; tiny rapids. |
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Term
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Definition
| Biggest, deepest feature. Curved deep area found on the outside of a mander or back of a rock/log. |
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Term
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Definition
| Water moving thru a well-defined channel. |
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Term
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Definition
| The amount of water in a stream. Measured in cu. meters /s of cu. ft./s |
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Term
| How do you determine the left or right bank of a river? |
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Definition
| Whatever side it is when you look downstream. |
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Term
| What part of the stream is the fastest(on a run)? |
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Definition
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Term
| At what depth should the average velocity be measured? What is this known as? |
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Definition
| 6/10 the original depth. The 6/10 rule. |
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Term
| What is the formula for discharge from a stream? |
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Definition
| Discharge=(depth*0.6)*(width)*(average velocity) |
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Term
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Definition
| Deposits on the inside of a meander. |
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Term
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Definition
| The outside of a bend where sediment is eroded. |
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Term
| How do you measure the discharge in a real stream? |
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Definition
| You have to set up a system of vertical sections and calculate the area that way and find all of the veolcities there. |
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Term
| Where do most rivers start? |
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Definition
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Term
| What increases as a river heads down stream and why? |
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Definition
| Energy, b/c PE=mgh and mass is increasing. |
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Term
| Is the Columbia River very old?? |
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Definition
| No, it is young, only about 6million yrs old. |
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Term
| How do they get fish past dams in the Columbia river? |
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Definition
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Term
| How much freshwater do the Great Lakes hold? |
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Definition
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Term
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Definition
| The saltiness of a body of water. |
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Term
| What is the most effective erosional agent? |
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Definition
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Term
| Where does running water get its energy? |
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Definition
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Term
| How does running water break up bedrock? |
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Definition
| It uses cutting tools like sand, pebbles, and even boulders that grind against the bedrock. |
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Term
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Definition
| The grinding action that cutting tools use against the bedrock. |
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Term
| How do rivers erode besides using cutting tools? |
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Definition
| It has a lifting effect that splits off and removes rock fragments. |
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Term
| What are the 3 ways rivers can carry rock material? |
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Definition
| In solution, in bed load, and in suspension. |
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Term
| How is rock material carried in solution? |
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Definition
| These minerals are dissolved and come from bedrock and mostly from groundwater. |
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Term
| How is rock material carried in suspension? |
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Definition
| Clay, silt, and fine sand are carried b/c they are stirred up and kept from sinking by stream turbulence. |
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Term
| The faster the stream, the more _________ it becomes. |
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Definition
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Term
| What can increase turbulence? |
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Definition
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Term
| How can rock material be carried in bed load? |
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Definition
| Sediment moves allong the bottom of the stream. Includes pebbles, boulders, stones, coarse sand grains. |
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Term
| How is sediment carried in US rivers? (%) |
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Definition
25%-Solution
25%-bedload
50%-suspension |
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Term
| As humans use land more, more sediment is carried in ___________. |
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Definition
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Term
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Definition
| Indicated by both the toatl amount of sediment in the stream and the size of those particles. |
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Term
| What does carrying power depend upon? |
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Definition
| Speed of stream and discharge. |
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Term
| When the speed of a stream doubles, the ________ _________ more than doubles. |
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Definition
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Term
| What does the speed of a stream depend mainly upon? |
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Definition
| The steepness of the stream. |
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Term
| What is the gradient of a stream? |
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Definition
| The steepness of its bed. |
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Term
| The streams of mountain regions and high plateaus have most likely formed ________. |
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Definition
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Term
| What are 3 names for steep valleys? |
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Definition
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Term
| What factors determine the time it takes for a river to form a canyon? |
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Definition
1. The kind of rock that must erode
2. The amount of water
3. The climate of the area |
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Term
| What is the base level of a stream? |
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Definition
| The level a stream cannot go below; level of body of water the stream flows into. |
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Term
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Definition
| A small river valley formed by a single heavy rain. |
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Term
| What is headward erosion? |
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Definition
| The wearing away of land at the head of the gully or stream valley. Makes gully longer. |
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Term
| When does a gully become a permanent stream? |
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Definition
| When erosion makes it cut below the water table. |
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Term
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Definition
| Regions so badly-eroded that they are difficult to travel through. |
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Term
| What is a divide? What is the Great Continental Divide? |
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Definition
| The high land that separtes one river valley from the next. GCD=Rocky mountains |
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Term
| What is a drainage basin/watershed? |
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Definition
| All of the land that drains into a river system. |
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Term
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Definition
| A river and all of its tributaries. |
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Term
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Definition
| Deep oval or circular holes in bed rock caused by whirlpools in a river. |
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Term
| What is a plunge pool and where are they found? |
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Definition
| A very large pothole. At the bottom of waterfalls. |
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Term
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Definition
| When a waterfall digs back into the cliff it is falling off, eventuall causing the top part of the cliff to break off. |
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Term
| Why do waterfalls and rapids occur? |
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Definition
| B/c water flows over hard igneous rock and then onto soft sedimentary rock. Or glaciers erode the land differently. |
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Term
| Are rapids and waterfalls permanent? |
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Definition
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Term
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Definition
| The part of a river valley floor where a river may overflow in times of heavy rain. |
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Term
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Definition
| As river goes around a bend erosion is fastest there which makes the bend bigger. Sediment is deposited on the inside of the bend which makes the bend even bigger. If one bend goes way left, the next one will go way right until there are series of broad curves across the flood plain. |
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Term
| How are oxbow lakes formed? |
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Definition
| When meanders combine to make loops and river breaks thru. Sediment is deposited in the direction the meander used to go and the entire meander is cut off from the river and makes a lake. |
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Term
| What are entrenched meanders? |
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Definition
| Deep canyons w/ meandering courses that are found on some high plateaus. |
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Term
| What causes a river to deposit sediment? |
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Definition
| A decrease in speed or discharge. |
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Term
| What causes a river's speed to decrease? |
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Definition
1. slope decreases
2. bed widens
3. meets an obstruction in the form of a curving bank or a rock outcrop
*4* River empties into ocean** (biggest one, all remaining sediment is deposited here) |
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Term
| Why does a river leave so much sediment on its valley's floor after a flood? |
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Definition
| As the flooding waters subside, the river's ability to hold its sediment is greatly diminished by losses in both discharge and speed. |
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Term
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Definition
| Level, fan-shaped deposits at the mouth of a RIVER. |
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Term
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Definition
| A sloping deposit of coarse sands and gravel found ON LAND at the base of a mountain. |
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Term
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Definition
| Elevated ridges on the flood plain formed when sediment is quickly deposited when the speed of the river dramatically slows as it rises onto the flood plain. |
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Term
| Describe a youthful river and its valley. (8 things) |
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Definition
-Runs fast
-Cross-section is a V
-Steepest
-No meanders
-Has rapids+waterfalls
-No flood plain
-Greatest erosive powers
-Carries sediments all 3 ways |
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Term
| Describe a mature river and its valley.(5 things) |
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Definition
-Not as steep
-Not as fast
-Starts to meander
-No waterfalls/rapids
-Has a flood plain |
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Term
| Describe an ancient river and its valley? (6 things) |
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Definition
-Wide flood plain
-Wide channel and bed
-Not very steep
-Slow
-Tons of meanders
-Oxbow lakes |
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Term
| Why is the outside curve of a meande rthe fastest part? |
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Definition
| B/c of centripetal force. |
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Term
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Definition
| Where the water is in the river normally. |
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Term
| What is a river's channel? |
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Definition
| Where the river possibly could be(includes flood plain). |
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Term
| What are 2 reasons why streams meander? |
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Definition
1. Difference in rock resistance
2. River hit base level |
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Term
| What helps to widen river valleys after they start to form? (hint:not water) |
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Definition
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Term
| All rapids were once ___________. |
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Definition
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