AI Prompt for Generating a SWMM5 inp file with Rules

 Below is an example prompt you can use (in ChatGPT or any advanced language model that understands SWMM5 syntax) to generate a syntactically correct SWMM5 .inp file. The prompt guides the AI through every relevant section, specifying required details, conventions, and typical structures that SWMM5 expects. You can adapt it to your particular system, specifying how many subcatchments, conduits, nodes, etc., or giving specific geometry, infiltration data, or rainfall series.

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Prompt Example for Generating a SWMM5 .inp File

System / Developer Instruction:
You are an expert in the EPA SWMM5 modeling software. You know how to create a syntactically correct SWMM5 .inp file with the proper sections and formatting. You will generate an entire SWMM5 input file that meets the following requirements:

1. File Sections
   • Include [TITLE], [OPTIONS], [EVAPORATION], [RAINGAGES], [SUBCATCHMENTS], [SUBAREAS], [INFILTRATION], [JUNCTIONS], [OUTFALLS], [CONDUITS], [XSECTIONS], [LOSSES] (if necessary), [REPORT], and [MAP]. (You may add other sections like [CURVES], [TIMESERIES], [PATTERNS], etc., if it suits the scenario.)
2. Title Section
   • Provide a descriptive title that briefly explains the model scenario.
3. Options
   • Use default or typical SWMM settings (e.g., FLOW_UNITS CFS in US units or FLOW_UNITS LPS in SI units).
   • Define the INFILTRATION method (e.g., HORTON, GREEN_AMPT, or CURVE_NUMBER).
   • Set START_DATE, END_DATE, REPORT_START_DATE, SWEEP_START, and SWEEP_END to some logical values.
   • Include DRY_DAYS and REPORT_STEP parameters.
   • Indicate typical settings, such as ALLOW_PONDING, MIN_SLOPE, FORCE_MAIN_EQUATION, and so on.
4. Evaporation & Rain Gages
   • Provide a simple EVAPORATION block, e.g., monthly average values or a constant.
   • Under [RAINGAGES], define at least one rain gage referencing a time series or user input.
     • Indicate the rain format (VOLUME, INTENSITY, etc.) and time interval. Make sure the rainfall  interval matches the generated rainfall time series interval. 
5. Subcatchments
   • Include at least two subcatchments for demonstration.
   • Give each subcatchment a unique name, outlet (e.g., a junction or an outfall), area, %imperv, width, slope, and curb length if needed.
   • Reference the corresponding rain gage name.
6. Subareas
   • Provide Manning’s n for impervious and pervious surfaces, depression storage, and any typical infiltration parameters (matching the infiltration method chosen in [OPTIONS]).
7. Infiltration
   • If using HORTON, specify MaxRate, MinRate, Decay, DryTime, MaxInfil.
   • If using GREEN_AMPT, specify Suction, Ksat, IMDmax.
   • If using CURVE_NUMBER, define typical parameters.
   • Ensure the infiltration parameters match the number of subcatchments.
8. Junctions & Outfalls
   • Create at least two junctions (including invert elevations and max depths).
   • Create one outfall with an assigned boundary condition (e.g., free outfall or fixed stage).
9. Conduits
   • Define at least two conduits connecting your junctions/outfall.
   • Specify conduit lengths, roughness (Manning’s n), inlet/outlet offsets (if any), and entry/exit node names.
   • Use the [XSECTIONS] section to define shapes and dimensions (e.g., circular pipes).
10. Losses (optional)

• If relevant, demonstrate how to specify local losses for conduits with expansions and contractions.

11. Report

• Set INPUT NO, CONTROLS NO, SUBCATCHMENTS ALL, NODES ALL, LINKS ALL, etc. to indicate what data to report.

12. Map

• Provide map coordinates or a bounding rectangle for the plan view.
• The [MAP] section at the end should be valid with typical bounding coordinates (e.g., 0.0 0.0 10000.0 10000.0).

13. Formatting & Syntax

• Strictly follow SWMM5 .inp file syntax:
  • Each section in brackets, e.g., [TITLE] on its own line.
  • Data lines separated by spaces or tabs.
  • Semicolons for comments.
  • No trailing commas or special characters that break SWMM5 parser rules.

14. Explanatory Comments

• Insert brief comments (prefixed with ;) to explain key sections or parameters, so the file is instructive as well as functional.

15. Validation

• The resulting .inp file must be fully valid in the official SWMM5 engine (EPA SWMM version 5.1 or later) with no syntax errors.
• If any advanced features (like [CONTROL] rules or [TAGS]) are included, ensure they’re properly structured.

Using these guidelines, generate the complete SWMM5 .inp file in plain text format. Include all sections, including required placeholders, so that a user could copy and paste the output directly into a SWMM .inp file, open it in the EPA SWMM5 GUI, and run a simulation without syntax or parse errors.

Remember: The file should demonstrate a realistic but simple model scenario—two subcatchments draining to a small network of conduits, at least one outfall, infiltration, and a straightforward rainfall definition, plus any required supporting data.

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How to Use This Prompt

1. Copy the System / Developer Instruction above into your AI interface (e.g., ChatGPT or another large language model platform).
2. Add any custom details you want, such as the number of subcatchments, infiltration method you prefer, coordinate system, or time series data specifics.
3. Send the prompt. The AI should respond with a fully formatted .inp file structure.
4. Review the generated text, copy it into a text file named YourModel.inp, then load it in EPA SWMM5 to verify or modify further.

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Example Output Snippet (Illustration Only)

Below is a small illustration of what part of the AI’s output might look like. (Note: This is not a full .inp file, just a sample snippet.)

[TITLE]
; -----------------------------------------------------
; Simple Example SWMM5 Model - Demonstration
; -----------------------------------------------------

[OPTIONS]
FLOW_UNITS              CFS
INFILTRATION            HORTON
START_DATE              01/01/2023
...
...

The final answer from the AI should be far more extensive, covering all sections and all data lines you requested in your prompt.

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Tips for Getting the Best Results

• Be Specific: If you need 5 subcatchments and 5 conduits, explicitly say so.
• Include Realistic Values: Provide typical infiltration rates, junction depths, or rainfall intensities to get a more practical file.
• Validate: After receiving the file, import it into EPA SWMM5 to confirm no syntax issues appear in the Status Report.
• Iterate: If you need changes (e.g., different infiltration method or additional controls), refine your prompt and re-run.

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Using this prompt approach should give you a ready-to-run SWMM5 .inp file—complete with all necessary sections, correct syntax, and logical water-balance setup.