GL 107 Earth Systems Science
K. Hannula
Discussion questions for 10/18/06
1. How do geologists use the term "reservoir"?
The term "reservoir" refers to any place where the substance in question is stored, even for tiny amounts of time. So earth's water resides in reservoirs that include the atmosphere, the oceans, and rivers, as well as man-made lakes.
2. Which reservoir contains the greatest proportion of water on earth? Which reservoir contains the greatest proportion of fresh liquid water?
most total water: oceans
most fresh liquid water: groundwater (glaciers contain more water, but it is not liquid)
3. Define the following terms:
gradient: steepness of river; height change/horizontal distance
discharge: volume of water that passes a point in a given amount of time; measured in cubic feet per second (cfs) or in cubic meters per second
headwaters: the place where a river begins
mouth: the place where a river flows into another body of water (such as the ocean)
base level: the elevation of the mouth of a river
4. How does discharge typically change down the length of a river?
Discharge usually increases downstream in a river, because tributaries add additional water to the main stream.
5. What are the differences between bed load, suspended load, and dissolved load of a stream?
Bed load: sediment that bounces or rolls along the bed of a river; the largest grains that a river carries at any time.
Suspended load: sediment carried in suspension in river water; sediment that gives water a muddy appearance. Smaller grains than the bed load.
Dissolved load: chemical ions carried dissolved in water. Includes the dissolved products of chemical weathering: Na+, K+, Ca2+, Mg2+
6. What determines the maximum size of particles a river can carry?
The velocity controls the size of particles a river carries.
7. What determines the maximum amount of sediment (maximum load) a stream can carry?
The discharge controls the amount (or load) of sediment a stream carries.