QGIS SCS to TUFLOW: Difference between revisions

This page presents a recommended method for the application of the U.S. Soil Conservation Service (SCS) (now known as the Natural Resources Conservation Service, part of the U.S. Department of Agriculture) rainfall-runoff model. TheyIt areis based largely on Technical Release No. 55 (TR55) prepared by the U.S. Soil Conservation Service (SCS, 1986).<br>

Currently, theThe tool is available for catchments in the Auckland Region¹, however, further models are planned to be added.

The model is recommended for use in stormwater management design in the Auckland Region. It has beenis designed as a standard tool that will provideprovides consistent results from different users. Key features of the stormwater runoff model are described below:

* A standard 24 hour temporal rainfall pattern, having peak rainfall intensity at middurationmid duration. Shorter duration rainfall bursts with a range of durations from 10 minutes to 24 hours are nested within the 24 hour temporal pattern.

The SCS to TUFLOW tool is part of the TUFLOW plugin which is explained further in the <u>[[TUFLOW_ViewerTUFLOW_QGIS_Plugin | TUFLOW Viewerplugin]]</u> page. The instructions on the page shouldcan be followed to install the QGIS plugin.

Alternatively, open the TUFLOW plugin menu and scroll down to ‘Extract SCS for TUFLOW (Beta)’. The tool is nominally in beta mode and we encourage feedback from external users, any comments or suggestions shouldto be sent to [mailto:support@tuflow.com support@tuflow.com].<br>

Once the ‘Extract SCS for TUFLOW (beta)’ tool has beenis selected, the SCS to TUFLOW Dialog will appearappears.

Currently, Auckland Region (TP108) is made available as the catchment location. This setup comes with curve number for impervious areas of 98, initial abstraction of 5mm for pervious areas and 0mm for impervious areas.<br>

[[File: Plugin_SCS_Simulation_SettingsSimulation_Settings_2.png]]

The manual approach is great for single catchment calculations. It requires one pervious and one impervious catchment component to be specified (either of which can be entered as zero if not present) and one additional impervious component if this is required. The suffix will get appended to the catchment ID and used in the final inflow csv and bc_dbase. Every suffix must be unique. Either time of peak or time of concentration can be specified directly. Alternatively, catchment parameters can be used for their calculation.<br>

The GIS approach allows a GIS layerslayer to be used as a source of catchment parameters and as such a catchment with multiple subcatchments can be processed in once. The subcatchment layer name is to be selected in the first drop down menu. Attributes from the layer will then become available to select as the catchment parameters in a similar way as for the manual approach. In addition, time of peak and time of concentration can also be calculated from a DEM and a streamline layer.<br>

Specify output location where inflows for every event in csv format, bc_dbase and TUFLOW event file willare to be saved. The tool also saves input_log text file that can be used as a check of whatinput has been entered into the toolparameters. This file isn't being read into TUFLOW.<br>

Once all above is set, hit the "Run" button in the bottom right corner. If there are any missing/incorrect information, the tool will prompt to fill/correct these before continuing. When all input data are filled correctly, the progress bar will getgets active and "Processing Data Into TUFLOW Format . . ." note will appearappears in the bottom left corner. Once all hydrographs and other outputs are processed the note will changechanges to "Finished Successfully".<br>

If you encounter any issues with the plugintool please email [mailto:support@tuflow.com support@tuflow.com].<br>