Skip to content

Usage

Attention

Before starting data download, it is necessary to set the project's CRS to EPSG:5514
How?

Data Download Tab (Download)

  • First, the area of interest must be specified

    • To download data within the current map view, select Current window extent
    • To download data defined by a polygon layer, select Polygon layer
      • This action will allow you to pick a polygon from the project in the dropdown below

  • Next, data for download may be selected

    • To download both Land Cover (Land Use) data and Hydrologic soil groups data, select Land Use + Hydrologic Soil Groups
    • To download only Land Cover (Land Use) data, select only Land Use
    • To download only Hydrologic soil groups data, select only Hydrologic Soil Groups

  • To start the download, click the Download button

  • To stop the download process, click the Abort button

ovl1

Layers combination tab (Combine layers)

  • In the Select Land Use layer dropdown, choose the Land Cover (Land Use) layer

    • If it was successfully downloaded in the previous tab, it will be set automatically as default choice
    • If you wish to use your own layer, it must contain an attribute field named LandUse_code with integer code values

  • In the Select Hydrologic Soil Group layer dropdown, choose the Hydrologic soil groups layer

    • If it was successfully downloaded in the previous tab, it will be set automatically as default choice
    • If you wish to use your own layer, it must contain an attribute field named HSG with integer values, where:
      • 1 represents group A
      • 2 represents group B
      • 3 represents group C
      • 4 represents group D
      • 0 may represent water bodies or unsurveyed areas with undefined soil group

  • Start combining the layers by clicking the Combine button

ovl2

Curve Number Tab (CN)

  • In the Select layer combining Land Use and HSG dropdown, choose the layer combined from the Land Cover (Land Use) and Hydrologic soil groups layers

    • If it was successfully created in the previous tab, it will be set automatically as default choice
    • If you wish to use your own layer, it must contain integer attribute fields named LandUse_code and HSG

  • The string field below shows the path to the CSV file for CN value assignment

  • Default path points to a CSV with CN values derived specifically for the Land Cover layer based on ZABAGED and LPIS data
  • To choose the location of your own CSV file, click the three-dot icon next to this field
  • To create the CN layer, click the Create CN layer button

ovl3

Direct Runoff Volume Calculation Tab (Runoff)

  • In the Select CN layer dropdown, choose the CN layer

    • If it was successfully created in the previous tab, it will be set automatically as default choice
    • If you wish to use your own layer, it must contain an attribute field named CN2 with values within the range (0.0 - 100.0>
      • Optionally, it may also contain an attribute field named CN3 with values within the range (0.0 - 100.0>

  • In the Initial Abstraction Coefficient (lambda) field below, you can enter a custom value of Initial Abstraction coefficient

    • Default value 0.2 is reasonable for most cases without any deeper knowledge of the hydrologic behaviour of the study area
    • Based on deeper knowledge, the Ia coefficient may be set to a different value, preferably within the tange 0.05 – 0.3

  • If you wish to calculate runoff depths and volumes produced by 6-hour design rainfall depths from the rain.fsv.cvut.cz service, select Use 6-hour rainfall depth from rain.fsv.cvut.cz option

    • Using the checkboxes in the Select Return Periods section choose the desired return periods of the rainfall depth

  • If you wish to calculate runoff depths and volumes using your own design rainfall depths, select User-defined rainfall depth [mm] option

    • In the string field below enter the depth of the rainfall depth in millimeters
      • To perform calculations for multiple depths, separate them with a semicolon ;

  • Start the calculation by clicking the Compute runoff volume button

ovl4

Batch Execution

Batch execution is enabled by run_batch.py located in the scripts directory. The batch job configuration is specified using a YAML configuration file. An example configuration is available in tests/batch.yaml. Example execution:

python3 scripts/run_batch.py tests/batch.yaml

For MS Windows, a batch file run_batch.bat is provided, which automatically sets up the QGIS runtime environment. Before running it, adjust the path to your QGIS installation in this file.

Using Local Data

Download LPIS and ZABAGED datasets and update the data source paths (URI) in the configuration files located in the config directory.