Project 2 – Landslide Hazard in the Blue Ridge

Your goal for this project is to develop the beginnings of a landslide hazard assessment for the mountain front of the Blue Ridge.  The first two steps taken in this project are to 1) produce a model that maps watersheds and streams from field GPS data that give the outlets of major basins, and 2) create a landslide hazard assessment model based on slope and aspect.  For the latter, I am not expecting you to be an expert on landslides, but you need to be a reasonable GIS manager given the input expert opinions below.

The input data are the GPS points for the area in Buena Vista and downstream along the Maury River (Word document) and the study area outline (feature class in project database), both available in the project two folder in the R:\courses\GEOL260\sharedwork\Projects\Project2.  DEM data are available from the USGS at the National Map. You should download the 1 arc-second data not 1/3 second (remember the artifacts in these data?)

You should make two models, one that creates stream and watershed maps for basins in the input data, and another that assess the landslide hazard using the DEM.  Given a new study area and DEM, these models could be applied by our neighbors in Nelson and Amherst counties. Please label elements of your model that need explanation (e.g., raster calculator equations).

The watershed/stream model should have a parameter that allows the user to input the drainage area in km-squared where stream channels initiate (start with 0.1 km-squared in this case). For output, streams should be clipped to the basins above the GPS points (these are the paths that the debris flows will follow). Caution:  ArcGIS may create multiple watershed polygons from one raster basin when you convert raster to vector. These one- to few-cell basins near the outlet should be eliminated (in the model preferably). The result should be an 8.5 x 11 layout exported to pdf that looks something like this but you might want to use the datum of the DEM instead of the one I used, right?

The landslide hazard model should be completed within the study area only and incorporate the knowledge of our local expert, who suggests that slopes above 25 degrees become increasingly hazardous, especially on north-facing slopes where soils remain wet longer.  You choose the way to incorporate this information into the overlay model and how much control of model output is governed by user input. A gradational result is preferred over a binary one, and slope should not be considered the same as aspect (a north-facing gentle slope is less hazardous than a south-facing steep slope). On a second 8.5×11 layout, display and/or analyze the hazard model results within the documented watersheds by area and/or degree of hazard.  Place on the layout a brief explanation of the hazard model criteria and results to a layperson (use the text rectangle tool from the insert tab on the layout menu).

You only need to build metadata for your GPS points layer and the DEM in the GIS, because everything else is created by the models. Use these map composition suggestions when you build your layout. You may choose to seek out other good sources for how to build clear, informative maps.

Post the following on a new portfolio page within your GIS class portfolio:

    • The location of the completed ArcGIS project (Path&Filename).
    • A snip of the watershed model with the name of the model within the project.
    • A snip of the hazard model with the name of the model and a brief explanation and justification of how the model hazard was calculated.
    • The two layouts

Add the project page to the table of contents of the portfolio splash page.

Project is due next Wednesday at class time.  Your project is done when you submit to canvas the location of the completed portfolio.

For extra credit (+5), you can do some extra work to evaluate the hazard downstream from each of the mapped basins based on people or structures at risk in the waterways below the GPS points.

Evaluation Rubric

Pts Excellent Good Fair Poor
Watershed model 25 23-25 – programs the correct process, has brief but necessary documentation, includes all steps to construct stream and basin maps from input DEM 20-22 – has most of the steps in the model, but maps/layers need adjustment outside the model, most documentation (information and help) 17-19 –model produces incorrect results or documentation is missing <16 – started but not finished by deadline
Landslide model 25 23-25 – well documented and composed model with appropriate analysis and output. Yields gradational landslide hazard emphasizing slope. 20-22 – Effective model with simple output that acknowledges difference between slope and aspect in hazard. Some documentation missing. 17-19 – Simple model with correct results some documentation. <16 –model incomplete or does not produce correct results
Watershed Layout 10 10 –the presentation uses the space wisely and fully, making all elements easy to read and interpret 8-9 –presentation would benefit from better arrangement, size or kind of layout elements 6-7 –poorly organized for presentation of data or use of space <6 – maps, titles and portions of necessary elements dropped into a layout with no thought to utility
Hazard Layout 10 10 –the presentation uses the space wisely and fully, making all elements easy to read and interpret. Clear paragraph 8-9 –presentation would benefit from better arrangement, size or kind of layout elements. Good paragraph. 6-7 –poorly organized for presentation of data or use of space. Fair paragraph <6 – maps, titles and portions of necessary elements dropped into a layout with no thought to utility. Poor or no paragraph describing criteria.
Metadata and project info 5 5 – metadata made and portfolio has requested info. 4 – something is missing 3 – one than one something is missing ≤2 – no metadata and/or portfolio troubles