Pilot yearFree, grades 9–12
The Inquiry Atlas
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Student handout

What Water Leaves Behind

What can running water tell us about the land it moves through, and how should we share what is left?

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The photographs

  1. A waterfall about two-thirds of the height of the frame drops down a rounded face of dark, wet rock and splits into two strands near the bottom. The wet rock is near-black and glistening; patches of bright green low plants grow on it and in the crevices beside it, in a band only a few centimeters wide at the water’s edge. To the left and right the rock is pale cream and gray, dry, and crossed by bare woody branches with few leaves. A still, dark pool fills the bottom quarter of the frame, its surface almost unbroken. Sunlight falls on the upper right; the lower left is in shadow.
    Photograph 1
  2. A wide, white waterfall drops from a notch at the top center of the frame into a deep canyon, falling perhaps its own height again in mist. The canyon walls are tan, ochre and gray rock, steeply bedded, with dark conifer forest on the upper slopes and along the rim. Below the fall the river runs green-gray through rapids at the bottom left. A broad rainbow arcs from the lower center of the frame up to the right, lying across the spray and the forested slope behind it.
    Photograph 2
  3. A narrow white waterfall drops the full height of the frame down a vertical sandstone wall of gold, tan and rust-orange rock. The rock is crossed by long dark vertical streaks. In the middle of the wall, on either side of the falling water, a broad patch of bright green low growth covers the rock where water spreads across it. At the foot of the fall is a shallow dark green pool, and in the foreground a pale sand and gravel beach. A few green leafy branches hang into the top left corner.
    Photograph 3
  4. A stream valley under deep, smooth snow, photographed from slightly above. The snow lies in broad rounded lobes that trace the meanders of the buried channel from the foreground to the middle distance, with a few narrow dark gaps of open water showing between them. Dark green conifers, snow on their branches, stand in the foreground on both sides and cover the hillside across the valley. The sky at the top of the frame is heavy gray cloud with a pale break near the right edge.
    Photograph 4
  5. A wide river, green-gray and lightly rippled, fills the bottom third of the frame. On the far side a cliff rises for most of the frame’s height in horizontal bands of red, ochre, cream and gray rock, deeply notched by side gullies, with a broad ledge partway up. The near-left shoreline is a slope of pale broken boulders with low green shrubs. A small white raft carrying several people sits on the water at the right, close to the far bank, and is a tiny fraction of the cliff’s height. The sky is deep blue with large white cumulus cloud on the right.
    Photograph 5

01. Setting the stage

You are looking at a place in the United States. Where do you think this is — and how much rain do you think it gets in a year?

02. Engaging with the story

Keep a running list of every place in these images where water clearly goes, and every place it clearly does not. Not what you think is happening. Just where the water is and is not.

03. Working the evidence

Observe (5 minutes). Record only what is visible. No explanations yet.

  • What do you notice first?
  • What materials, textures and colors can you see?
  • Where exactly is the green, and where exactly is it not?
  • Look again for a full silent minute. What did you miss?

Reflect (6 minutes). Now generate and test explanations.

  • What do you think is happening here?
  • Look at the rock the water is not touching. What does it tell you about how much rain this place gets?
  • If it does not rain much here, where is this water coming from?
  • Compare photograph 1 with photograph 3. Both show water falling onto rock with a pool at the bottom. What is the pool doing?
  • What is missing from these images?

Question (4 minutes).

  • What do you wonder about: who, what, when, where, why, how?
  • Standing there with any instrument you wanted, what would you measure first?

04. Delving deeper

Read all three tables before you answer anything.

Table 1. Where Earth’s water is
WhereShare of all Earth’s waterShare of fresh water
OceansAbout 96.5 percent—
Ice caps and glaciers1.74 percent68.7 percent
Groundwater1.69 percent30 percent
All riversAbout 1/10,000th of one percent—

Source: U.S. Geological Survey, Water Science School.

Table 2. Snow as a reservoir, and what lands on it
MeasureValue
Share of water supply from snowmelt, in some western statesAs much as 75 percent
What a snowpack doesStores cool-season precipitation and releases it in the warm season — a reservoir nobody had to build
Effect of heavier dust settling on that snowPeak runoff at Lees Ferry, Arizona arrives on average 3 weeks earlier
Effect on the year’s total runoffReduced by more than 1.0 billion cubic meters, about 5 percent of the annual average
When the dust increase beganA fivefold increase from disturbed soils was already under way by the late 1800s

Sources: U.S. Geological Survey; Painter et al., PNAS, 2010.

Table 3. One river, by the numbers
MeasureValue
LengthAbout 1,400 miles
Basin areaAbout 250,000 square miles
States it servesArizona, California, Colorado, Nevada, New Mexico, Utah, Wyoming
People relying on itBetween 35 and 40 million, for some or all of their municipal water
Share used by agriculture70 percent
System storage todayAbout 36 percent of capacity, after long-term drought

Source: U.S. Bureau of Reclamation, Colorado River Basin.

05. Reflecting and projecting

Part A. Read the evidence. Based on the photographs alone, what can you conclude about the water in these places? And just as important, what can you not conclude?

Part B. Make the call. A water district that draws from a snow-fed river has applied to increase its annual withdrawal by 10 percent. The river’s flow changes from year to year with the snowpack, and the water already promised to existing users adds up to more than the river has carried in recent years. Should the state approve the increase?

  • Your claim. State your position in one or two sentences.
  • Your evidence. At least two specific observations from the photographs, plus one item from Tables 1, 2 or 3. Name the source of each.
  • Your reasoning. Explain the scientific and practical principles that connect your evidence to your claim.

Students may submit as a written paragraph, a recorded verbal explanation, an annotated photograph, or a labeled diagram. All four are acceptable and the rubric applies equally.

06. Take action

Choose one.

  1. Your own water. Where does the water from your tap come from? Name the source, the watershed, and how far it travels. If it is groundwater, find out how long ago it fell as rain.
  2. The snow line. Find the snowpack record for the mountain range nearest you, or the nearest one that has one. What has it done over the last thirty years, and who depends on it?
  3. Dust and snow. Read about dust deposited on mountain snow. Where does the dust come from, what does it do to melt timing, and does it change your answer to question 6?

07. The rebuttal

Your rebuttal. Someone reaches the opposite conclusion from the same evidence. State their position as fairly as you can, then explain why the evidence favours yours. If you think the evidence does not settle it, say so and explain what would.

Discussion questions

  1. In photograph 1, look at the rock the water is not touching. What does its color and its plant cover tell you about how much rain this place gets?
  2. Photographs 1 and 3 both show water falling onto rock with a pool at the bottom. What is the pool doing to the rock?
  3. In photograph 2 a rainbow stands in the air below the falls. What has to be in the air for that to happen, and what does it tell you?
  4. Photograph 4 shows almost no moving water. Is that stream doing less work than the others, or the same work at a different time?
  5. In photograph 5 the raft is a few meters long and the cliff is hundreds of meters high. Which of those two did the river make?
  6. Open question. A river’s flow comes mostly from mountain snow, and the amount of snow varies from year to year. The water has already been promised to cities and farms. Who should go short in a dry year, and how would you decide?

Photography: Greg Smith. The Inquiry Atlas, a project of The Method Project.

Free to print and use with your classes. Wider reuse terms are still being finalised — please do not republish or redistribute it beyond your own students yet.