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Application Exercise:

If you'd like to practice selecting and then completing a graphic organizer, please read the following passage from a hydrology textbook, Elements of physical hydrology. Select one of the graphic organizers that follows this passage, print it, and then fill it in.

The Hydrological Cycle

The motion of water can be described at many different scales. The fundamental concept of hydrology is the hydrological cycle--the global--scale, endless recirculatory process linking water in the atmosphere, on the continents, and in the oceans. We can think of the recirculatory process in terms of reservoirs or compartments that store water (the oceans, atmosphere, etc.) and the movement of water between them. Within the various compartments of the hydrological cycle, water can be stored in any one of three separate phases or states: gas (vapor), liquid, or solid. For example, water in the atmosphere can exist as vapor (the concentration of water vapor is expressed as humidity), in liquid (cloud droplets, rain drops), or in solid phase (ice crystals, snowflakes). Similarly, all three phases of water can be found on and below the land surface. Movement of water from one compartment to another can occur in any of the three phases. For example, the movement of water between the oceans and atmosphere occurs in vapor phase (evaporation from the ocean surface), liquid phase (rain on the ocean surface), and solid phase (snowfall onto the ocean surface).

Solar energy drives the hydrological cycle; gravity and other forces also play important roles. The dynamic processes of water vapor formation and transport of vapor and liquid in the atmosphere are driven largely by solar energy. Precipitation and the flow of water on and beneath the Earth’s surface are driven primarily by gravity. Within partially dry soil, gravitational and other forces are responsible for the movement of water.

The hydrological cycle can be considered to "start" anywhere, but let us consider atmospheric water first. As hydrology is concerned mainly with water at or near the Earth’s surface, from our point of view the dominant process involving atmospheric water is the precipitation of water upon the land surface. The portion of the precipitation that reaches the land surface as solid precipitation (mostly snowfall) can be retained temporarily on vegetation or ground surfaces, or accumulate in seasonal snowpacks or in permanent snowpacks known as glaciers. Considering liquid precipitation (rain), a portion can also be retained temporarily on vegetation surfaces or in surface depressions, and portion enters into soil (infiltration) and a portion flows over the land surface first into small rivulets and ultimately into larger streams and rivers. This last process is called surface runoff, which can be augmented by runoff during periods of snowmelt. The portion of rainfall that infiltrates into the soil can also follow one of several paths. Some of the water evaporates from the soil and some is returned to the atmosphere by plants (transpiration). We often refer to the total evaporation and transpiration from vegetated land surfaces by the term evapotranspiration. The remaining water continues to move downward through the soil and recharges the saturated portion of the subsurface, becoming groundwater. At lower elevations, groundwater discharges into streams and rivers, or directly to the ocean (groundwater runoff). Water evaporates from the surfaces of the oceans and thereby replenishes the water in the atmosphere. Thus we have returned to the particular compartment that we considered first, atmospheric water (pp. 5-6)

Passage from Hornberger, G., Raffensperger, J., Wiberg, P., & Eshleman, K. (1998). Elements of physical hydrology. Baltimore: Johns Hopkins UP.

Now, please click the PDF icons to download and select one of the graphic organizers. Fill it in according to the information presented in the passage on the water cycle.

Venn Diagram PDF Cycle Diagram PDF Fishbone Diagram PDF

Venn Diagram

Cycle Diagram

Fishbone Diagram