CEG 795
Spring 2006
Water Resources Modeling and GIS
Dr. Thomas Piechota
TEST #1: Due Monday, March 6th, 7:00AM
(NO LATE EXAMS WILL BE ACCEPTED)
GUIDELINES:
1. You are required to do all the work on your own. If you copy work from your
classmates or work together, then you will both receive an F on the exam.
2. Prepare your answers to the items below in a neat format and use a word
processor where necessary. The ITEMS noted below are the things you
need to do for the test and prepare an answer and/or figure. All maps
and answers should be neatly prepared and you will be graded on the
quality of the figures.
3. After you finish your analysis, prepare a zip file that has all the data and
analysis that you performed for the analysis. This will be a zip file of your
test1 directory where you should do all of your work. Bring this zip file to me
prior to 7:00AM on Monday, March 6th.
PRELIMINARY INFORMATION
1. Download the zip file (test1.zip).
2. Unzip the data into the a directory test1.
3. The following data files will be included:
a. lvboundary.shp (shape file of the boundary of the Las Vegas Valley
watershed with elevations).
b. lvwatershed.shp (shape file of Las Vegas Valley watersheds)
c. DEM\valgrid (grid file of Las Vegas Valley DEM, resolution = 333 meter x
333 meter) NOTE: This file covers an area larger than the Las Vegas
Valley watershed boundary. All elevations are in feet.
d. fcfarcs_l (shape file of Clark County storm drain channels)
e. fcfbasin_p (shape file of Clark County detention basins)
f. sclmajor_l (shape file of major streets)
g. stations_x (shape file of stations in Flood Threat Recognition System,
FTRS)
4. Load this data into ArcGIS.
OK, you should be set to go. Have fun and good luck!!
PART A: Querying GIS data and Spatial Analysis in ArcGIS (save all this work in a
file parta)
ITEM 1: Answer the following questions
a. What is the coordinate system that is used for all these files?
b. What is the grid cell size for the valgrid file?
c. How many storm channels are there in the Las Vegas Valley watershed?
d. How many storm channels are located in the C1 Channel watershed?
e. How many of the storm channels from (b) are constructed?
f. How many Flood Threat Recognition stations in Clark County are located
above 3000 feet?
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g. How many of these stations are within ½ mile of a major street?
h. How many detention basins in the Las Vegas Valley are located within ½ mile
of a major street?
i. How many times do flood control channels cross the Strip (i.e., Las Vegas
Boulevard)?
ITEM 2: Create a map (MAP 1) that only has the streets, storm drain channels,
detention basins, and FTRS stations within the C1 Channel watershed. Include the
boundary of this watershed.
PART B: Spatial Analysis in ArcGIS (save this work in a file test1b)
ITEM 3: Answer the following questions using the Spatial Analyst tool and the DEM for
the Las Vegas Valley area?
a. Use the lvboundary.shp file as the boundary to create a DEM that is only
within the Las Vegas Valley watershed. Save this new DEM as the grid file
lvwaterdem.
b. What is the highest elevation (feet) in the watershed?
c. What is the lowest elevation (feet) in the watershed?
d. What is the mean elevation (feet) in the watershed?
e. If the snow level for a particular storm was going to be 2500 feet, how much
(%) of the watershed would be covered with snow?
f. Create a map (MAP 2) that displays the area covered with snow. In the
background include the streets for the entire watershed.
g. If a dam were built at the outlet of the Las Vegas Valley watershed that had a
top elevation of 1600 feet, how much of the Las Vegas Valley watershed
would (km2) be flooded?
h. Using increments of 100 feet, create a graph (GRAPH 1) of area flooded
versus dam elevation from 1600 feet to 2000 feet.
i. Create a map (MAP 3) showing the streets, and the area flooded when the
top of the dam is at 1800 feet.
j. How many miles of streets would be flooded if the dam was built with a top
elevation of 1800 feet?
PART III: Watershed Delineation in ArcGIS (all of this work in a folder call
test1/partc with a file name test1c)
1. The valgrid is a grid file that is already to use for watershed delineation.
2. Use the Terrain Preprocessing Tool in ArcGIS to step through the process of
identifying subwatesheds in the Las Vegas Valley and the identification of
individual drainage points for each subwatershed. Below are a few points to
consider when performing this analysis:
a. Use the fcfarcs_l layer as a linear feature when performing the DEM
reconditioning.
b. When performing the stream definition, use a 40 km 2 area as a threshold
for identifying a stream.
3. Complete the process of identifying all the subwatersheds in the Las Vegas
Valley using the Terrain Preprocessing Tool.
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ITEM 4: Answer the following questions
a. What is the maximum value in the flow accumulation layer?
b. How many stream segments are defined?
c. How many catchments are defined?
d. What is the maximum size (km2) catchment?
e. What is the common field between the Catchment, DrainageLine, and
DrainagePoint layers?
ITEM 5: Prepare a map (MAP 4) showing all the subwatersheds in the Las Vegas Valley
based on your analysis. The map should also include the drainage points and drainage
lines.
ITEM 6: Zoom into a particular area and compare the subwatersheds delineated with
the major subwatersheds in the shapefile (lvwatershed). Create a map (MAP 5).
ITEM 7: Zoom in on a particular area and compare the streams identified in your
analysis with the channel locations in fcfarcs_l. Create a map (MAP 6).
ITEM 8: Use the Point Watershed Delineation tool to identify the watershed boundary
upstream of the station located at the Lower Duck Creek Detention Basin.
ITEM 9: Prepare a map (MAP 7) of the Lower Duck Creek Detention Basin watershed.
Use your creativity to prepare a map that would be used in a drainage study for this
watershed and note the size of the watershed (km2) on the map?
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