WATER LAB

INTRODUCTORY GEOLOGY WATER 5.11 STUDENT RESPONSES 1. What type of stream drainage pattern is present on this map? This may be easier to determine by examining the tributaries to the main stream. a. dendritic @ c. radial d. rectangular 2. Based on the drainage pattern type, does the bedrock underlying this area consist of rocks uniformly resistant to erosion or rocks alternating between resistant and non-resistant layers? a. uniformly resistant bedrock (* b. alternately resistant and non—resistan@ 3. Are the rocks likely tilted and folded or horizontal? a. tilted and folded b. horizontal 4. Are streams in this area downcutting or laterally eroding? a. downcutting b. laterally eroding.>) 5. In which stage of the cycle of stream erosion is this area? a. old age @ c. youthful 6. Calculate the stream gradient of Grape Creek in ft/mile. Use the index contour just above the “m” in Temple Canyon for your initial spot. Measure the gradient to the index contour past the word Creek (the last contour before it reaches Arkansas River). The distance between these areas is ~1.6 miles (measured along the curving distance of the non-magnified stream). What is the gradient? a. 15'/mile b. 100’/mile ( c. 125'/mile ) d. 200'/mile 7. Observe the stream on the Omaha N, Nebraska-Iowa quadrangle. In which stage of the cycle of stream erosion is this area? — < :;l,d\ag\e> b. )‘nature c. youthful 8. Compare the contour intervals from the Royal Gorge, Colorado map (map 5.1) to the Omaha N, Nebraska-Iowa map. Would you expect the gradient of the Missouri River in Nebraska to be greater or less than the gradient that you calculated for the Grape River in Colorado? ess than the Grape River gradient b. greater than the Grape River gradient Page | 113

INTRODUCTORY GEOLOGY WATER 9. Locate the state boundary between Nebraska and Iowa along the Missouri River. Why does the boundary depart from the river channel? hen the boundary was created, Iowans wanted the Carter Lake area in their state b. the boundary follows the course of the river at the time that it was drawn; the river as since moved c. none of the above 10. What is the term for the geologic feature called Carter Lake? a. entrenched meander xbow lake c. cutbank d. point bar 11. Was Carter Lake cut off before or after the state boundary between Nebraska and Iowa was drawn? efore b. after 12. On which date did a flood event have a recurrence interval of 0.5? @2/27/2013 b. 10/13/2009 ¢. 3/10/2011 d. 4/20/2015 13. Of the following dated flood events, which one would you expect to happen more often? a. 8/27/2008 'b,/2/24/2013 c. 2/6/2010 14. Observe your best fit line. What approximate discharge would be associated with a 50 year recurrence interval? a. 2,000 cfs b. 4,750 cfs @,500 cfs d. 14,000 cfs 15. Flood stage, or bankfull stage, on Sweetwater Creek occurs at a discharge of ~4,500 cfs. According to your best fit line, what is the recurrence interval of such a discharge? a. 0.5 years years c. 25 years d. 50 years Page | 114

INTRODUCTORY GEOLOGY WATER 25. Keeping the abrupt topography change in mind, which of the following is true? n the northern portion of the map, the area is underlain by limestone 26. 27. 28. b. In the southern portion of the map, the area is underlain by limestone Locate the Louisville and Nashville Railroad line just south of Hwy. 31. Would this be an easy location to maintain a railroad? a. Yes No How would one describe this river? a. Straight _ b. Meandering c. Low sinuosity d.)Braided In this stream, erosion is occurring on the because , while deposition is occurring on the because a. point bars; the fastest velocity water flows to this point; cut banks; the slowest veloc- ity water flows to this point b. point bars; the slowest velocity water flows to this point; cut banks; the fastest veloc- ity water flows to this point @cut banks; the fastest velocity water flows to this point; point bars; the slowest veloc- 29. 30. ty water flows to this point d. cut banks; the slowest velocity water flows to this point; point bars; the fastest veloc- ity water flows to this point How would one describe this river? a. Straight b. Meandering c. Low sinuosity raided What factors control the course of this river? a. Steep gradient and high discharge b. Low gradient and low discharge @ Low gradient and abundant sediment supply d. Steep gradient and low sediment supply Page | 116

INTRODUCTORY GEOLOGY WATER 31. The river in this area has a rather particular pattern, what geologic process caused this? a. a meander eroded through its bank and created an oxbow lake b. the river is in a karst terrain and disappeared into the ground c. the river is following patterns, likely faults, in the underlying bedrock (e during a flood the river breached the natural levee flowing into the floodplain 32, Zoom out and examine the surrounding area, what geological hazards are likely in the area? a. sinkholes @looding of urban areas c. erosion and subsidence d. none of the above 33. What type of drainage pattern is present in this area? a. Trellis b. Dendritic c. Rectangular @Radial e. Deranged 34. What does this type of drainage pattern indicate about the area? a. rocks in the area are homogeneous and/or flat lying b. rocks in the area are alternating resistant and non-resistant, forming parallel ridges and valleys @tream channels radiate outward like wheel spokes from a high point d. stream channels flow randomly with no relation to underlying rocks or structure 35. What type of drainage pattern was present in this area? a. Trellis endritic c. Rectangular d. Radial e. Deranged Page | 117

INTRODUCTORY GEOLOGY WATER 42. Notice the general shape of this feature. It is thought to have formed by the runoff of either precipitation or groundwater. What type of drainage does this appear to be? a. Trellis endritic c. Rectangular d. Radial e. Deranged Map 5.4 | (appearing on foliowing page) Mammoth Cave, Kentucky 1:24,000 topographic map Author: USGS Source: USGS License: Public Comain Page | 119

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