ICM InfoWorks and ICM SWMM RED (Rainfall Event Data) file format

 This document describes the RED (Rainfall Event Data) file format,  used as an input for hydrological simulations, within the InfoWorks ICM software suite or other related tools.  

File Structure:

The RED file is a structured text file containing rainfall data and associated parameters. It consists of the following record types:

• Records 60-63 (Optional): These records, if present, must be at the beginning of the file. They define analysis parameters, ground condition parameters, and unit hydrograph parameters, that are used in a simulation or a batch set of simulations.
• Record 20 (Title): Contains a title or description of the rainfall data. There is only one Record 20 per file.
• Record 21 (Global Variables): Defines global parameters for the rainfall event, such as event number, start date/time, rainfall time step, number of rainfall profiles, and a global Urban Catchment Wetness Index (UCWI). There is only one Record 21 per file.
• Record 22 (Rainfall Event Data): Contains data for each rainfall profile, including a local UCWI (overriding the global value if not 0), an areal reduction factor, and a profile title. There is one Record 22 for each profile defined in the file.
• Record 23 (Rainfall Hyetographs): Contains the actual rainfall intensities (in mm/hr) for each time step and for each profile. There are multiple Record 23s, one for each time step, with each record containing data for all profiles.

Record Details:

• Record 20 (Title):

  • Column 1: Flag (must be 0)
  • Columns 2-80: Title (text)

• Record 21 (Global Variables):

  • Columns 1-5: Event Number (integer)
  • Columns 7-14: Start Date (dd/mm/yy or ddmmyyyy)
  • Columns 16-20: Start Time (hh:mm, 24-hour clock)
  • Columns 21-25: Rainfall Time Step (seconds, integer)
  • Columns 26-30: Number of Profiles (integer)
  • Columns 41-50: Urban Catchment Wetness Index (UCWI, decimal with 1 decimal place)

• Record 22 (Rainfall Event Data):

  • Columns 1-10: Local UCWI (mm, decimal with 1 decimal place. If 0, the Record 21 value is used).
  • Columns 21-30: Areal Reduction Factor (decimal with 1 decimal place)
  • Columns 41-80: Profile Title (text)

• Record 23 (Rainfall Hyetographs):

  • Columns 1-80: 10 columns of 8 characters each, representing rainfall intensities (mm/hr, decimal with 2 decimal places) for each profile. Each record represents a single time step.

• Record 60 (Analysis Information):

  • Columns 1-10: Analysis Interval (minutes, integer)
  • Columns 11-20: Analysis Duration (minutes, integer)
  • Columns 21-30: Antecedent Dry Weather Period (ADWP, hours, decimal with 3 decimal places)
  • Columns 31-40: Evaporation (mm/day, decimal with 3 decimal places)

• Record 61 (Ground Conditions):

  • Column 1: Profile Number (integer)
  • Columns 2-10: API 30 (Antecedent Precipitation Index for 30 days, mm, decimal with 3 decimal places)
  • Columns 11-19: depPaved (Depth of depression storage on paved areas, mm, decimal with 3 decimal places)
  • Columns 20-28: depPerv (Depth of depression storage on pervious areas, mm, decimal with 3 decimal places)
  • Columns 29-37: NAPI for Soil Type 1 (mm, decimal with 3 decimal places)
  • Columns 38-46: NAPI for Soil Type 2 (mm, decimal with 3 decimal places)
  • Columns 47-55: NAPI for Soil Type 3 (mm, decimal with 3 decimal places)
  • Columns 56-64: NAPI for Soil Type 4 (mm, decimal with 3 decimal places)
  • Columns 65-73: NAPI for Soil Type 5 (mm, decimal with 3 decimal places)

• Record 62 (NAPI Limiting Factors):

  • Column 1: Profile Number (integer)
  • Columns 2-10: Reserved.
  • Columns 11-80: Maximum cumulative NAPI values for Soil Types 1-5 (mm, decimal with 3 decimal places), one value per 9-column field.

• Record 63 (New Unit Hydrograph Parameters):

  • Column 1: Profile Number (integer)
  • Columns 2-10: Initial Soil Moisture (Cini, mm, decimal with 3 decimal places)
  • Columns 11-80: Reserved for future use.

Key Features and Implications:

• Multiple Profiles: The format supports multiple rainfall profiles within a single file, allowing for spatial variation of rainfall or different storm scenarios to be represented.
• Time-Series Data: Record 23 provides time-series rainfall data, defining the temporal distribution of rainfall intensity.
• Antecedent Conditions: Records 21, 60, 61, and 62 allow for the specification of antecedent conditions (UCWI, ADWP, API, NAPI, depression storage), which can significantly influence runoff generation.
• New Runoff and Unit Hydrograph Methods: Records 61, 62 and 63 specifically support newer methods for runoff calculation and unit hydrograph generation (likely ReFH, which stands for Revitalized Flood Hydrograph method).
• Batch Processing: Record 60 suggests that the format is designed to support batch processing of multiple simulations.

In essence, the RED file format provides a structured way to input rainfall data and associated parameters into a hydrological model, supporting multiple rainfall profiles, antecedent conditions, and newer hydrological methods. The format's flexibility makes it suitable for a range of hydrological modeling applications.