Step 1: Add a DEM File

To start, open your VOSWMM project. From there, navigate to the “GIS Tools” tab and select “Add Layer”. This is where you will need to browse your computer and choose a high-resolution DEM file.
Remember that the quality of your results relies heavily on the quality of the DEM file you select. Also, note that the command is designed to work with DEMs, which are based on the metric system, and VOSWMM operates within this system for this command.

Step 2: Access the Create StorageUnit Tool

Once you’ve added the DEM file, access the “Create StorageUnit” tool by first heading to the “Micro-Drainage” tab in the VOSWMM tab. Then, select “Create StorageUnit.”

Step 3: Assign Storage Unit Properties

In the “Create StorageUnit” window, you’ll need to assign various properties for your storage units.
First, select your DEM file from the “DEM Layer” dropdown list.
Second, specify the “Minimum Depth (m)” for your storage units in meters.
Third, set the “Minimum Area (m²)” for your storage units in square meters.
Fourth, choose a location on your computer where you want to save the generated layers. These layers include the Depression layer in pixel, the depression shape file (polygons), and the filled layer in pixel. These generated files can be valuable for future reference or project modifications.

Step 4: Start the Storage Unit Generation

After you’ve configured all the settings, click the “Start” button. This action triggers the tool to check the criteria you’ve provided and subsequently generate the storage units based on the DEM and your specified parameters.

Step 5: Verify the Depth-Area Curve

Once the storage units are created, you can click on them to verify the Depth-Area curve. Keep in mind that these values are estimations for your design, and you may need to make further adjustments. It’s also important to note that the precision of decimal values on the Depth-Area curve depends on the “Results Precision” settings that you’ve defined in the general options of VOSWMM.