Removal of groundwater can cause subsidence. If removalof

Where does most of Earths precipitation occur?

As water is precipitated onto the land, where does it go? Where does most of the water on land end up?

Distinguish between porosity and hydraulic conductivity.

If a hole is dug in the unsaturated zone, does it fill with water? Why or why not?

Compare and contrast the unsaturated zone with the saturated zone.

What types of soil allow the greatest amount of rainfall to soak in?

What is an artesian system, and how is it formed?

Describe at least one consequence of overpumping groundwater.

How does rainwater become acidic? How does this affect limestone?

How do stalactites and stalagmites form?

Name three erosional features caused by groundwater in carbonate rocks.

What is the difference between a cave and a cavern?

What is meant by stream gradient, and how does it affect stream velocity?

What happens to stream speed when the discharge of a stream increases? What happens to discharge when the speed of a stream increases?

How does the shape of a stream channel affect flow?

Which transports more sediment: laminar flow or turbulent flow? Why?

Describe three ways flowing water erodes a stream channel.

What factors are responsible for the formation of a stream valley?

Under what conditions do curvy, meandering rivers form along a floodplain?

What types of streams and stream valleys do we generally find in high, mountainous regions?

Streams transport great quantities of sediment from one place to another. What is the size range of the particles that can be carried by a fast-moving stream?

What is a delta?

How is a glacier formed?

In what two main ways do glaciers flow?

Under what conditions does a glacier front advance? How about retreat?

What is the most common depositional landform created by glaciers?

What erosional features are likely found in an area of alpine glaciation? See Figure 22.37.

What land features are formed from glacial deposits?

How do sand dunes migrate?

How are ripple marks formed?

As a glacier moves across the land, it loosens and picks up rocks in its pathway. These rocks, embedded at the glaciers base, scrape the underlying bedrock to form striations. To see how this happens, make your own mini-glacier. Cover the bottom of a small plastic container with sand, fill the container with water, then freeze until solid. Remove your glacier from its container and hold it between gloved fingers. With the sand-side down, rub the ice over a piece of soap. What happens to the surface of the soap?

As wind blows across the land surface, it picks up small particles of sand. You can demonstrate how wind moves sediment. Cover the bottom of a cake pan with a flat layer of cornmeal (about 2 cm deep). With a straw, gently blow across the surface of the cornmeal. What happens to the surface? Place a small obstruction (small pebble, shell, screw) in the center of the pan and continue to blow. What happens behind the obstruction?

We know that most of Earths water is in the oceans. The remaining 2.8% is Earths freshwater supply. Of this freshwater supply, what percentage is found in the polar ice caps? In groundwater? In streams, lakes, and rivers? Hint: Calculate the freshwater supplies to be equal to 100%.

A particular stream widens as it progresses downstream. Using your answers for parts (a) and (b), briefly describe the changes in discharge. (a) If the cross-sectional area of the stream is 1 m2 and the stream speed is 0.5 m/s, what is the streams discharge? (b) If the cross-sectional area of the stream increases to 2 m2 and the stream speed remains 0.5 m/s, what is the streams discharge?

aquifer. Before the pump was turned on, the hydraulic gradient and the flow rate were measured to be 0.0001 and 1 m3/day, respectively. With the pump turned on, the gradient becomes 10 times larger. By how much does the flow rate increase?

Darcys law gives us the volume flow ratevolume per time (for example, cubic meters per day, m3/day). Another way to express volume is on a per-unit-area basis. For example, if we have a 1@m3 cube, we know its base is 1 m2the cross-sectional area of the cube and its height is 1 m. If we fill the cube with water, we can say we have 1 m of water per unit area. Darcys law can be rearranged to calculate the volume flow rate per unit area. This is called the specific discharge, which has units of length per time (for example, meters per day, m/day). Completing parts (a) through (c) will illustrate how specific discharge relates to the volume flow rate. (Hint: Assume that the units for hydraulic conductivity are m/day and the units for cross-sectional area are m3.) (a) Suppose 1 m3 of water is pumped from a well into an empty cylindrical tank. If the water level is 2 m above the base, what is the cross-sectional area of the tank? Hint: Volume of a cylinder = pr 2h = area of base * height. (b) If it takes half a day to pump the 1 m3 of water into the tank, what is the flow rate in terms of both volume per time and specific discharge? (c) Write Darcys law so that it calculates the specific discharge.

The hydraulic head at point A is 209 m. At point B, which is 300 m from point A, the hydraulic head is 210 m. The aquifer is composed of sand with a hydraulic conductivity of 150 m/day. Groundwater flows directly from point B to point A. What is the specific discharge?

Rank, from greatest to least amounts, the distribution of Earths freshwater: (a) groundwater; (b) polar ice caps and glaciers; (c) streams, rivers, and lakes; (d) soil moisture.

Put in order, from beginning to end, the steps in stream formation: (a) runoff forms, (b) raindrops strike the ground, (c) water begins to run downslope, (d) gullies form.

In descending order, rank the rocks in terms of their susceptibility to chemical erosion: (a) marble, (b) limestone, (c) sandstone, (d) quartzite.

A stream becomes a river as it moves down gradient. Give the sequence in the evolution of a stream: (a) meandering pattern, (b) rapids, (c) delta.

Rank, from greatest to least, these forces of stream channel erosion: (a) chemical erosion, (b) abrasion, (c) hydraulic action.

Streams carry sediment as well as water. List, the following types of sediment in order of deposition: (a) boulders and cobbles, (b) pebbles and gravel, (c) sand, (d) clays and mud.

A delta is the end of a river. Going from offshore toward the shoreline, rank these according to sediment size: (a) cobbles, (b) pebbles, (c) sand, (d) clay.

Glaciers are like icy rivers that flow downgradient. Rank, from first to last, the stages in glacial flow: (a) basal sliding, (b) crevasses, (c) accumulation and thickening of glacial ice, (d) calving.

What percentage of Earths supply of water is fresh water, and where is most of it located?

Where does most rainfall on Earth finally end up before becoming rain again?

In a confined aquifer, water in a well can rise above the top of the aquifer. What is this system called?

In an unconfined aquifer, how high can water rise in a well that is not pumped?

How is the local hydrologic cycle affected by the practice of drawing drinking water from a river and then returning sewage to the same river?

Is water in the unsaturated zone called groundwater? Why or why not?

In an aquifer, if the water table next to a stream is lower than the water level in the stream, does groundwater flow into the stream or does stream water flow into the ground? Explain.

As runoff into streams increases, which variables of stream flow increase?

What is meant by channel geometry?

What happens to stream speed if the discharge in a stream doubles while the channel remains the same size and shape?

If discharge is held constant and the width of the stream channel decreases, what happens to stream speed? What effect will this have on the stream channels depth?

What three variables influence the speed of stream flow?

How does frictional drag play a role in the external movement of a glacier? How does this drag affect the internal movement?

What are some possible sources of stream flow?

In the formation of a river delta, why are larger particles deposited first, followed by smaller particles farther out? Defend your answer.

What causes the formation of distributaries off the main channel of a river delta?

What is a sinkhole? What factors contribute to its formation?

Which of the three agents of transportationwind, water, and icetransports the largest boulders? Why?

Which of the three agents of transportationwater, ice, and windtransports only small rocks?

Carbonate rocks form mainly in marine environments. Why do we find abundant carbonate deposits on continental land?

Are underground rivers ever found in nature? Defend your answer.

Do you think a stream with laminar flow can become turbulent without the volume of water in the stream increasing? Defend your answer.

Describe the formation of stalactites.

Why is surface water both a creator and a destroyer of sediments and sedimentary rocks?

Why do point bars form on the inside bends of meandering streams?

How is a roche moutonne different from a drumlin?

What well-known landscapes have been carved by glaciers?

How do deposits from glacial ice differ from rocks deposited by rivers?

Removal of groundwater can cause subsidence. If removal of groundwater is stopped, will the land likely rise again to its original level? Defend your answer.

Must a streams speed increase in order for it to carry more sediment? Explain.

What distinguishes a huge block of ice from a glacier?

Why do crevasses form on the surfaces of glaciers?

Does all the ice in a glacier move at the same speed? Explain.

What is the significance of the large, out-of-place boulders that are sometimes found in glacial deposits?

How are sand dunes formed?