Embedded Files
Table of Content
Table of Content
- Background
- Description
- Results
- Summary
- Reference
Background
Background
The primary purpose of this Lab is to learn how to further work on DEM, it included:
- Delineating a watershed from a DEM
- Deriving a drainage network
- Applying some common morphometric analyses to DEMs
I have been asked to create a high quality map and make some morphometric analysis of the Big Cottonwood Creek Watershed. Find below the area of interest.
Click image for larger view
Description
Description
Click items below for detailed description of the methods used in conducting these tasks
Results
Results
Task 1: Watershed Delineation
The map illustrates the differences between the delineated watershed boundary for the Cottonwood Canyon area near Salt Lake, Utah using 10 NED DEMs and the watershed boundary created by the Utah AGRC. Total area= 129 km square. The caption showed that created watershed is a bit different from the existing one, some stream did not extend so much like the existing one, also the stream moved in direction that deviates from the existing path. Click image for large view.
Task 2: Drainage Network Defination
I created a Strahler stream order classification of the entire Big Cottonwood Creek watershed using 5000 flow threshold and calculated the length of each order. The stream order created is a bit different from the existing watershed as explained above. Click image for larger view
Task 3: Morphometric Analysis
Slope Analysis
The slope percentages for the Big Cottonwood Creek Watershed range from 0-384.83; where 45 degrees is 100% and 90 degrees approaches infinity . It is shown that there are many steepy slopes along the ridges and lower slopes along the valleys. It was noted that there are more steep slopes near the mouth of the canyon. Click image below for larger view.
Curvature Analysis
The figures below show the standard, plan and profile curvature created. The table below displays the zonal statistics for the slope and different curvatures created from the Big Cottonwood Canyon Watershed. The value (-40.29 to 29.85 with a mean of 0.023) obtained for the profile curvature show that the slope is made up of more concave (positive value) than convex( negative values) surfaces. Therefore, the water stream flow will decelerates more in the area. The plan curvature value ranged between -20.6 to 18.9 and mean value of 0.023 ; this shows that the slope are composed of more divergent and convergent slopes. Hence, more divergence of water flow in the region.
The combined curvature show a slope that support the fast deceleration and divergence of the water flow in the region. Click image for larger view.
Zonal Statistics Analysis of Big Cotton Canyon.pdfClick here for larger view.
Conclusion
Conclusion
The operation involved in creating the watershed was accurate and successful.
Reference
Reference
Understanding Curvature. Retrieved from https://blogs.esri.com/esri/arcgis/2010/10/27/understanding-curvature-rasters/ 24th March, 2017.
Lab 08A - Morphometric Analyses. Retrieved from http://gis.joewheaton.org/assignments/labs/lab-8---choice/lab08a 24th March, 2017.
Utah GIS Portal, https://gis.utah.gov/data/#. DEMs. Retrieved on 24th March, 2017.
Google Sites
Report abuse