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User Guide

  1. If you have not used erams before, start here.

Create an IWBMIso Project

  1. On the left hand side of the page, click on the “Projects” box.
  2. When the Projects page opens, click on “Create Project.”
    1. Enter a name for your project, such as “My IWBMIso Project.”
    2. Under “Project Type,” select “IWBMIso.”
    3. Click “Okay.”
  3. Click GIS/Analysis to bring up the project’s map viewer.

IWBMIso Map Interface

  1. For an overview of how to use the map, see here
  2. IWBMIso adds two elements to the map interface, a dashboard

    and a project selector



The Dashboard

Create/Edit Basin


Import Project Data

IWBMIso projects have GIS data available for selected regions. Select a region from the drop list and click Go to load the layers associated with the region. This list is populated by directories located in /var/erams/data/IWBMIso/regions. This will always contain a DEM of the area and possibly any lakes and streams.

Select Regional DEM

This is the base DEM for the project.

Select Area of Interest

The project DEM may be quite large, so to reduce the HRU computation time, it is recommended that you clip the DEM to the area of interest. Click Create Area of Interestto put the map into draw-rectangle mode. A popup will appear at the top of the map where you can create the AOI once you are happy with the rectangle chosen or cancel the operation. Otherwise you can select any DEM.

Select Work Directory

There are a large number of intermediate files that the creation process can generate, so to make your layers manageable, it is recommended that you place them in a work folder. Use Create Work Directory to create a new folder in your project.

Select HRU Layer

This will be the target of the Merge Lake into HRU, Add Sub-basin ID to HRU, and Publish to Directory.

Select Sub-basin Layer

This will be the target of the Merge Lake into Sub-basin and Publish to Directory.

Select Lake Layer

This will be the source of the Merge Lake into Sub-basin and Publish to Directory.

Create HRU Layer

Using the area-of-interest DEM, a watershed layer can be generated that can be used as HRUs. See the Taudem Watershed Toolbox documentation for a detailed description.

Create Sub-basin Layer

Using the Taudem Watershed Extraction Tool, sub-basins from the outlet points that were generated during the HRU creation step.

Merge Lake Layer into HRU and Sub-basin Layer

Complete the HRU and sub-basin generation process by merging any lake polygons onto each layer. Each lake will be a new HRU or subbasin. This will split existing polygons along the lake borders.

Add Sub-basin ID to HRU Layer

If HRU polygons are dissolved or otherwise edited, then the sub-basin ID of each HRU will need to be updated.

Remove Small HRU and Sub-basins

Use the Polygon Dissolve Tool to remove sliver HRU or sub-basins created during either the initial generation or lake overlay.

Publish To Directory

When the HRU and sub-basin layer generation is complete, you will need to let the IWBMIso project know that a new scenario is available. This is done by copying the layers into a new folder with the name of the new scenario. The scenario’s layers will be renamed to ‘HRUs’, ‘Subbasins’, and ‘Lakes’, if a lake layer was part of the analysis.