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Flashcards in Quiz 7 Deck (30)
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1
Q

What is one problem with relying on levees and/or flood walls for protection from flooding?

A

One problem with relying on levees/flood walls is that eventually they will all fail, and that currently most of the levees/flood walls are not up to current building standards

2
Q

How/why does channelization work to reduce flooding in urban areas?

A

Channelization is the process of straightning, deepening, and possibly widening the channel of the river. This is done some more water can flow through the river before flooding starts. The problems with this is that it can create really fast currents that can be deadly, like with the Los Angeles River.

3
Q

Discuss two sensible land uses that floodplains should be zone for, and explain why these land uses are “sensible”?

A

One sensible land use is for parks, this is because parks have very little infrastructure to them and can be easily abandoned during a flood. A second possible land use is for grazing, because when it floods you just don’t let the animals graze in that location.

4
Q

Although costly, why is the Federal Emergency Management Agency’s (FEMA) buyout program better than federally-funded structural protections (dams, levees, flood walls) to flooding?

A

FEMA’s buyout program is better the federally-funded structural protections because the area is just abandoned and they won’t incur future costs due to floods.

5
Q

How does FEMA’s buyout program work?

A

The buyout program is a completely voluntary program where the owner’s house is appraised at it’s preflood value and the owner is given that value for their home. Then the owner has to agree to not purchase another home on the floodplain again, and that place hast to remain open forever.

6
Q

Why are detention basins now required in new subdivisions in Cedar Falls?

A

Detention basins are required in new subdivisions, because they slow the amount of water coming out of a river/creek after periods of intense rainfall. This helps to reduce downstream flooding.

7
Q

Why are stream terraces better sites than floodplains for locating cities, railroads, and highways?

A

Stream terraces are safer places to live because they are relatively flat and higher above the river than the floodplain. So most high terraces don’t get flooded

8
Q

What are two reasons why floodplains are ideal sites for agriculture?

A

They are excellent for agriculture because they are relatively flat, and have silt rich stream deposits that are good for growing crops.

9
Q

Describe two ways that Lake Mead behind Hoover Dam is useful to people in the southwestern U.S.

A

Lake Mead is useful to people in the southwester part of the US because it provides recreatioal activities for the people in the area, and it also provides their drinking water.

10
Q

Why did Des Moines go without a drinkable water supply for almost a full month in 1993? How could it have been prevented?

A

The building flooded and the pumps stopped working. The my could have prevented this by not building the water treatment facility on a flood plain

11
Q

Detail the steps involved in forming glacial ice.

A

To form glacial ice, it must be in an area where snow falls faster then it melts. Then as the snow accumulates on the glacier it compacts and turns into ice.

12
Q

List where are two continental ice sheets are present today.

A

Greenland, Antartica

13
Q

How do glacial kettles form? List a place in the Upper Midwest where kettles are found.

A

As a glacier retreats it leaves behind blocks of ice, Then that block of ice gets buried in glacial out wash, and as the ice melts it creates a small depression called a kettle. These can be found in Story county Iowa

14
Q

List a landform (not a place where it is found) created by a continental ice sheet that is mined. Describe how the glacial landform you have listed above naturally formed. How do humans make use of the glacial deposits mined from the landform?

A

A valley train carries glaciofluvia sediment away from resessional or terminal morraines and deposit them further away and confined to a valley. These are mined for their gravel which can be used to help build roads.

15
Q

How did the Loess Hills in western Iowa form? Be sure to include all the steps related to the formation of loess, not just the depositional stage.

A

During the Ice Age, glaciers advanced down into the mid-continent of North America, grinding underlying rock into a fine powder like sediment called “glacial flour.” As temperatures warmed, the glaciers melted and enormous amounts of water and sediment rushed down the Missouri River valley. The sediment was eventually deposited on flood plains downstream, creating huge mud flats.During the winters the melt waters would recede, leaving the mud flats exposed. As they dried, fine-grained mud material called silt was picked up and carried by strong winds. These large dust clouds were moved eastward by prevailing westerly winds and were redeposited over broad areas. Heavier, coarser silt, deposited closest to its Missouri River flood plain source, formed sharp, high bluffs on the western margin of the Loess Hills. Finer, lighter silt, deposited farther east, created gently sloping hills on the eastern margin. This process repeated for thousands of years, building layer upon layer until the loess reached thicknesses of 60 feet or more and became the dominant feature of the terrain.

16
Q

How did Lake Missoula form? What caused Lake Missoula to flood the Columbia River Valley and its tributaries?

A

Lake Missoula was formed by a glacial ice dam which blocked a river from flowing downstream. Then when this ice dam broke it caused a massive flood throughout the Columbia river valley and its tributaries.

17
Q

Why did Lake Bonneville form during the last glaciation? List what is the remnant of Lake Bonneville is called today.

A

There was a water climate during the last glaciation and salt lake

18
Q

Why is soil considered the “grand recycler”?

A

Soil is considered the grand recycler because it breaks down organic material into humus which allows things to grow into it.

19
Q

What is the difference between soil texture and soil structure?

A

Soil texture describes the average distribution of particle sizes. Soil structure is how those particles are clumped together in aggregate.

20
Q

Discuss two properties of soil (physical, chemical, or both) that are largely determined by the humus content of the soil.

A

One property of soil that is determined by the humus content is the color of the soil. Soil that has a lot of humus will be black, or dark brown in color. Another property of soil is that soils with a lot of humus in them will stick together more when wet.

21
Q

How does the content of clay in soil affect permeability?

A

Because clay particles are so small water won’t flow through the soil as well and will likely be retained on the surface of the soil

22
Q

Describe why the amount of clay in soil strongly affects soil fertility (moisture is not involved in fertility).

A

Clay rich soils have more cation exchange capacity which will result in a low pH level and they won’t be able to grow any more plants.

23
Q

List the two most common parent materials of soils in Iowa?

A

dows till, and Peoria loess

24
Q

Discuss two changes that happen to a soil as it ages. Assume no soil erosion or additions of sediment to the surface as it ages.

A

Over time the soil will increase in the amount of clay present in the soil, and the amount of unweathered rock will decrease

25
Q

What are two physical or chemical properties of soils (one physical and one chemical, or two of either) in hot, humid environments, other than moisture content?

A

A phyiscal property of soils in hot humid environments are that they have high aluminum and iron oxides in them that make the color of the soil red and the soil is mostly made up of clay.

26
Q

How does caliche form in soil? In which soil order is it most common?

A

whey the amount of water passing through the soil is not enough to completely remove salts the cocentration of sat an dother materal increases over time which forme a discrete layer called caliche. It is commonly found in the aridisols

27
Q

Briefly discuss two general properties that apply to most A horizon of soils.

A

Most A horizon’s have lots of organic material in them. and they also have lots of insects and earth worms

28
Q

Why (two reasons) are Histosols found in some parts of north-central Iowa?

A

because of the Des moines lobe the area has low level reliefs that had poor drainage networks. histosoles are also found because of the water staying I that area

29
Q

List a place in the United States where Entisols are common.

A

The nebraska sand hills

30
Q

Why are Mollisols common across much of Iowa?

A

Because Iowa was a part of the Great plains tant that region and the roots of the grasses allowed for little leaching and development of a large humus layer