Geology Quiz Answers Chapter 16

Chapter 16: ● The discharge of a river is measured in cubic _____ per second. ○ Meters or feet ● What is a drainage basin? ○ The naturally defined area that a stream drains ● Smaller subsidiary channels that feed the main channels of rivers are ______. ○ Tributaries ● The drainage pattern associated with areas where the rocks have the same resistance to erosion is a ______ pattern, whereas _____ drainage patterns are found on symmetrical mountains. ○ ○ Dendritic ○ Radial ● A stream in a mountainous area that is carved from bedrock is called a ______ stream. ○ Bedrock ● The amount of water flowing through a channel over a given amount of time is called its ______. ○ Discharge ● A stream that flows year-round is a(n) ______ stream, whereas a(n) _______ stream does not flow the entire year. ○ Perennial ○ Intermittent or ephemeral ● Rivers are dynamic systems driven by precipitation and _____. ○ Gravity ● Match the river drainage pattern with the appropriate description of its geology. ○ Structurally controlled pattern ■ Drainage occurs on eroded layers or structures and then cuts across a ridge to follow a different weak layer. ○ Radial drainage pattern ■ Drainage is found on symmetrical mountains such as volcanoes. ○ Dendritic drainage pattern ■ Treelike pattern develops on rocks with similar resistance to erosion. ● The base level of a river is the _____ elevation to which the river can erode. ○ Lowest ● Besides sea level and rock type, the other two primary factors that influence a stream or river's profile are _______ and ________. ○ Climate ○ Tectonics ● A cutoff meander may develop into an _______ lake. ○ Oxbow ● ______ are formed as flowing water collects in natural cracks or low spots. Once formed, these capture additional runoff within the drainage basin. ○ Channels ● Waterfalls, lakes, and large boulders are landforms that characterize ______. ○ the headwaters of mountain streams ● When water flows chaotically through narrow channels or over large rocks and other debris that partially block the channel, ______ are formed. ○ Rapids ● Which of the following are primary factors that influence a stream's profile? ○ Sea level ○ Rock type ○ Tectonics ○ Climate ● These are formed when a steep drainage enters a broad valley and the sediments and debris are deposited. ○ ○ Alluvial fans ● The process of meander formation begins when a difference in roughness on the ______ causes water to move faster on one side of the channel than on the other. ○ Bottom ● A stream that flows in a network of many interconnected rivulets around numerous bars is a ________ stream ○ Braided ● As water flows, it accumulates in natural cracks, which eventually form ______ rather than spreading across the land. ○ Channels ● What types of streams typically deposit clay- to sand-sized sediments? ○ Low-relief streams ● Define the landforms associated with the headwaters of mountain streams. ○ Waterfall ■ Occurs when a stream or river's gradient is so steep that water goes over a ledge or cliff ○ Rapid ■ Occurs along a river and is characterized by turbulent water ○ Lake ■ Occurs where water is impounded by some obstruction ● Select common features located along low-gradient rivers. ○ River terraces ○ Single channels ○ Meanders ○ Floodplains ● When the gradient of a stream steepens or the channel is constricted by bedrock or obstacles, the flow of water becomes ______ forming ____ ○ turbulent; rapids ● When steep, narrow drainages enter broader, more gentle valleys and streams deposit the large sediments they are carrying, ______ ______form. ○ Alluvial fans ● The feature formed when a river deposits its sediment near its mouth is a(n) ______. ○ Delta ● Select the answer that is not a factor in the deposition of deltas. ○ Chemical makeup of sediment ● What types of sediments or rocks are deposited by low-relief streams? ○ Clay ○ Silt ○ Sand ● Construction of dams causes an interruption of river flow. River ______ are deposited upstream of the dam, shortening the life of the reservoir. ○ Sediments ● Do changes in tectonics, human development, and geology affect river systems? ○ Yes ● ______ are formed as rivers slow down when they reach their mouth and empty into an ocean. ○ Deltas ● Rank in order from the beginning (at the top) the processes necessary to create entrenched meanders. ○ A meandering river flows across a floodplain. ○ A tectonic event causes an uplift, causing the river to erode downward. ○ Further incision by the river creates more entrenchment. ● From the list below, select the factors that control the deposition of a delta. ○ Wave action ○ River and ocean ice ○ Vegetation ○ Discharge ○ Sediment load ● What is a natural bridge? ○ An arch-shaped features that span a (former) stream ● Select consequences to a river when a dam is constructed. ○ Water released from the dam is clear (no sediment) and has a new capacity to erode and transport sediments downstream. ○ The dam creates a temporary base level for the river. ○ The dam causes the river to deposit its sediment load upstream of the dam. ● What is a flood? ○ Water overflows a stream's channel. ● Select conditions that have an effect on the flow of river systems over time. ○ Runoff ○ Tectonism ○ Geology ○ Dams ○ Climate ● Select all the natural causes for flooding from the list below. ○ Regional precipitation ○ Snowmelt ○ Local heavy precipitation ○ Eruption of snow-covered volcano ● As meanders develop on a floodplain and either the base level drops or a tectonic event causes uplift, the meanders deepen and become ________. ○ Entrenched or incised ● Select the human-caused flooding events from the list of flood causes below. ○ Dam failure ○ Urbanization