gis

Introduction to Lab

Background

You have used DEMs effectively to make persuasive maps (Lab 02), and now have built DEMs from raw data (Lab 07). At the heart of GIS raster analysis is the ability to analyze surfaces or landscapes to generate interesting and useful information from the elevation data in a DEM. In this lab, we use the Salt Lake County USGS NED 10m DEM from Lab 06 to delineate the watershed for Big Cottonwood Creek and to perform a series of morphometric analyses to better understand the physical characteristics of the watershed.

All the data you need for this lab was produced or provided in Lab 06.

Prerequisites

Lab 01, Lab 06 - Task 1

Lab Objectives

The primary purpose of this lab is to show you how to do more with DEMs than just make pretty maps. Upon completion of the workshop exercise, you will have:

Delineated a watershed from a DEM
Derived a drainage network
Appled some common morphometric analyses to DEMs

Meets Course Learning Outcomes 2 & 4.

Slope Analysis

Slope Analysis of 10 m USGS DEM for Big Cottonwood Canyon

Lab Tasks

This week, you are still working for the same old ‘Big Cheese’ environmental consulting firm who specializes in watershed management (congratulations, you were not fired last week). Your boss has reviewed the work you did comparing and analyzing resolution differences for DEMs in Big Cottonwood Canyon and has come back with some further instructions.

For this assignment, you should work with the 10 m DEM you used in Lab 6 - Task 1.

He would like you to:

Task 1
- Delineate the watershed for Big Cottonwood Creek
- Create figure demonstrating difference between delineated and existing BCC watershed
Task 2
- Perform a Strahler stream order classification of the entire Big Cottonwood Creek watershed
- Create figure demonstrating difference between existing stream map
Task 3
- Calculate slope, plan-form curvature, and profile curvature for the watershed
- Create Table reporting Mean and STD, minimum, and maximum slope, profile and planform curvature for watershed

Extra Credit (20 pts)

You may repeat these analyses on a higher resolution DEM from Task 1 of Lab 6 to see to what extent the results change (5m autocorrelated DEM or 2m LiDAR for whole watershed). Evaluate and discuss the potential benefits and detriments of using a higher resolution DEM to perform these analyses. Compare flow accumulation channel networks, min max mean slopes for watershed, and total watershed size.

Lab Instructions

What to Submit

Task 1- Watershed Delineation

Create a figure showing a difference between your delineated watershed and the shapefile acquired from the UT AGRC.
Select a basemap, layers, and scales/extent that help convince your boss that the delineation is accurate

Task 2 - Strahler Stream Order

Create a figure displaying the Strahler stream order classification for the Big Cottonwood Creek watershed
- Use effective symbology
- Provide the flow accumulation threshold value used to define stream channels
- Include a figure that demonstrates locations where your delineation both aligned with and differed from from streams mapped on a basemap image from ESRI or a stream file downloaded from the AGRC.
- Report the total stream length (in kilometers) for each stream order

Task 3 -

Provide 3 captioned figures (at appropriate resolution to show detail) displaying raster results of slope, planform curvature, and profile curvature analyses for the Big Cottonwood Creek watershed
Provide table summarizing minimum, maximum, mean, and standard deviation statistics for 3 watershed characteristics (slope, planform curvature, and profile curvature) for Big Cottonwood Creek watershed on your webpage
Slope
Profile curvature
Planform curvature

Make sure your lab conforms to the general lab submission guidelines. Submit a URL for this lab’s webpage.

Additional Resources:

Lab Introduction Lecture Slides

Lab 8 Slides - Shannon Wing Belmont Spring 2014

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