GY 301: Geomorphology Lab 8: Groundwater and Karst Geomorphology Page 1 of 5Your Task: Today’s lab deals with the interpretation of geomorphological features that typically occur due to the action of groundwater. The exercises should be able to be completed within the 2 hour lab period provided that you do focused work on them. The most common scale (1:24,000) will not easily fit on the small desks that we have in room 42 and today, some of the questions require you to compare maps. Once again, it might be a good idea to push a couple of desks together. Please put the desks back in rows when you are done. Outside of the normal lab session, maps are available in the storage cabinets in room 337. They are alphabetically sorted. Due Date: 5:00 PM, October 30th PART ONE: GROUNDWATER Problem 1: Ashby, Nebraska 15' Sheet. Note: This quadrangle map area covers part of the Sand Hills region of western Nebraska. The surface units are composed of very porous sand and there is little vegetation in the area a) Why are there so few streams on the map? _________________________________________ _____________________________________________________________________________________ ____________________________________________________________________________ [2 points] b) Water Table contours: Match the upper right corner of your 8.5 x 11" sheet of tracing paper with the northeast corner of the quadrangle. Your tracing paper should cover the approximate northeast quarter of the map area. Trace the lakes (blue) onto the tracing paper, including the lake elevations which are printed inside the lake boundary on the quadrangle. Assuming that the lake elevations represent the elevation of the water table, contour the water table with blue pencil using a contour interval of 5 feet. On your tracing paper label the value of each contour. From the contour map show the direction of groundwater flow with a red arrow. [10 points] c) If the owner of the Adams Ranch in section 34, T26N, R39W polluted the groundwater with pesticide is it possible that the Davis Ranch well (section 32, T26N, R38W) would be affected at some later date? Explain why or why not relative to parts (a) and (b). ______________________________________________________________________________ _____________________________________________________________________________________ ____________________________________________________________________________ [3 points] Another question pertaining to this map follows on the next page→ Name: ________________________ Raw score: ______/50 Percentage: __________/100%GY 301: Geomorphology Lab 8: Groundwater and Karst Geomorphology Page 2 of 5d) Calculate the hydraulic gradient in feet per mile units from your contour map in part (a).(Show your work for partial credit). _________________________________________________________ [5 points] Problem 2: Pelican Lake, ND 7.5' Sheet. Note: This quadrangle map area is underlain by glacial till a) There are a lot of closed depressions on this map that are mostly due to glacial processes (something that we will get into next week). Note that many are filled with water, but many others are only intermittently filled. Can you offer an explanation for why this might occur? ______________________________________________________________________________ _____________________________________________________________________________________ ____________________________________________________________________________ [3 points] b) Three point problem. Complete the following 3 point problem using the water levels in Pelican Lake (Sect 36, T148N, R79W), Brush Lake (Sect 27, T147N, R79W) and the unnamed lake in Sect 18, T147N, R78W). Use a red arrow to indicate the direction of groundwater flow. Pelican Lake Brush Lake Unnamed lake (7 points)GY 301: Geomorphology Lab 8: Groundwater and Karst Geomorphology Page 3 of 5PART TWO: KARST Problem 1: A portion of the Interlachen, FL 7.5' Sheet. (See next page) a) What overall features of this quadrangle tell you that it is underlain by limestone and an area of karst? ______________________________________________________________________________ ___________________________________________________________________________ [2 points] b) Consider the following premise: You are an engineer with the town of Interlachen (middle east side of the map). A major corporation would like to build a brand new golf course just south of the town. It will bring in a lot of tourist dollars. They want to drill 2 water wells to irrigate the course. Will you authorize it? Why or why not? ______________________________________________________________________________ _____________________________________________________________________________________ ____________________________________________________________________________ [3 points] c) In general, the northern 2/3 of the map has higher relief than the southern 1/3. The northern portion has no streams while the southern portion does. Assuming that these 2 areas reflect different stages in the evolution of karst topography, will the southern 1/3 become more like northern 2/3 or vice versa? ______________________________________________________________________________ _____________________________________________________________________________________ ______________________________________________________________________________ _____________________________________________________________________________________ ____________________________________________________________________________ [5 points]GY 301: Geomorphology Lab 8: Groundwater and Karst Geomorphology Page 4 of 5GY 301: Geomorphology Lab 8: Groundwater and Karst Geomorphology Page 5 of 5Problem 2: Mammoth Caves, Kentucky 15' Sheet. We only have one map; it will be posted during the lab session. Also note that hachures on contour lines are very small on this map. a) Observe the general landform features of this map. In what way(s) are the landforms covering the southern third of the quadrangle different from the northern two thirds? (Hint consider the processes responsible for their formation). ______________________________________________________________________________ _____________________________________________________________________________________ ____________________________________________________________________________ [3 points] b) Observe the