SWMM5 rain.c Summary

 The rain.c file in SWMM5 handles the import and storage of external rainfall data into the SWMM rainfall interface format. It supports various formats for reading data, processes the rainfall records, and integrates them into the SWMM model for use in simulation.

Key Functions and Features of rain.c:

1. rain_open():

• This function opens the binary rainfall interface file for reading or writing, depending on the mode (SCRATCH_FILE, USE_FILE, or SAVE_FILE).
• If needed, it creates a new rainfall interface file and writes the header information, including the rain gage details.

2. rain_close():

• This function closes the rainfall interface file and the RDII processor if they are open.

3. createRainFile():

• This function writes rainfall data from all rain gage files into a single SWMM rainfall interface file. It ensures that the gage data is correctly added to the file and includes appropriate header information.

4. rainFileConflict():

• This function checks if there are conflicts in the station ID across multiple gages, ensuring that each gage has a unique station ID.

5. addGageToRainFile():

• This function reads the rainfall data from a specified rain gage file and writes it to the rain interface file. It also handles different formats, including NWS, AES, and CMC formats.

6. initRainFile():

• This function initializes the rainfall interface file for reading. It verifies that the file is correctly formatted and retrieves the gage data.

7. findGageInFile():

• This function looks for a specific rain gage's station ID in the rainfall interface file and retrieves its data.

8. findFileFormat():

• This function determines the format of the rainfall data file, supporting formats like NWS_TAPE, NWS_SPACE_DELIMITED, NWS_COMMA_DELIMITED, and others.

9. readFile():

• This function reads the rainfall records from the gage's data file and writes them to the SWMM rainfall interface file, based on the file format.

10. readNWSLine():

• This function reads a single line of rainfall data from NWS-style data files (including space-delimited, comma-delimited, and online formats), parses the values, and writes them to the interface file.

11. saveAccumRainfall():

• This function saves accumulated rainfall data by evenly distributing the total rainfall over the accumulation period and writing it to the rainfall interface file.

12. saveRainfall():

• This function writes the current rainfall value to the SWMM rainfall interface file, including the date and time of the reading.

13. setCondition():

• This function sets the condition code based on flags in the rainfall data, such as indicating missing or deleted periods.

14. initRainFile():

• This function initializes the rainfall interface file for reading, ensuring that the file format is correct and that the rainfall data can be properly read.

Summary of Key Concepts:

• Rainfall Data Formats: The file supports multiple rainfall data formats, including NWS tape, space-delimited, comma-delimited, AES, CMC, and standard SWMM formats. It identifies the format and processes the data accordingly.

• Data Parsing and Writing: The functions read and parse the rainfall data, ensuring that it is correctly formatted and written into the SWMM rainfall interface file. The data includes station IDs, rainfall depths, and timestamps.

• Rainfall Processing: The file handles the conversion of rainfall values, accumulation of rainfall over time, and the inclusion of rainfall values with proper timestamps in the SWMM binary rainfall file.

• Error Handling: The functions ensure that errors in data formatting, conflicts between station IDs, and other issues are handled gracefully, with appropriate error messages being reported.

Overall, the rain.c file is crucial for handling external rainfall data in various formats, converting it into a format suitable for SWMM, and integrating it into the simulation model. It plays a vital role in importing and processing rainfall data from various sources, ensuring that the data can be used for hydrologic and hydraulic modeling within SWMM.