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Simple Sewer Capacity Analysis with InfoWorks ICM

Jun 25, 2025

Summary

  • The meeting provided a step-by-step walkthrough of using InfoWorks ICM (standard edition) for utilities looking to perform DOD Capacity Analysis and master planning, particularly for sanitary sewer networks.
  • Topics included data import, dry weather flow modeling, linking flows to parcels, and comparing ICM results to traditional spreadsheet methods.
  • Attendees discussed practical implementation details, common challenges, and the benefits of using ICM for more accurate and flexible analysis.
  • No major decisions were made, but the session clarified workflows and addressed questions about connecting parcel data and using SQL queries within ICM.

Action Items

  • None specified for follow-up in the transcript.

Workflow for Sewer Capacity Analysis in InfoWorks ICM

Overview and Audience

  • The workflow targets utility engineers performing DOD Capacity Analysis and planning for growth using sewer modeling.
  • Intended for users seeking improved accuracy over spreadsheets and equation-based approaches.

Step 1: Data Import into InfoWorks ICM

  • Key required data layers: pipes (conduits), manholes (nodes), and parcels (imported as subcatchments).
  • Parcels can be polygons or address points, associated with subcatchments in ICM for dry weather flow allocation.
  • InfoWorks ICM allows robust mapping from various GIS sources, Excel, and databases, with tools for data cleaning and editing.
  • Fields like roughness coefficients can be inferred from material types, and updates from GIS can be streamlined using saved import configurations.

Step 2: Creation of Dry Weather Flow (Wastewater) Profiles

  • Wastewater profiles are constructed using 24-hour diurnal curves for each land use type (e.g., residential, commercial).
  • In ICM, flows are applied as per-capita but can be scaled to per-area by assigning population equal to parcel area.
  • Each flow curve captures daily variation—peaks and lows—resulting in more realistic modeling compared to steady-state analysis.

Step 3: Linking Parcel Data to Flow Profiles

  • Land use IDs from parcel data are joined to wastewater profiles via SQL queries in ICM.
  • Parcel (subcatchment) population is set to area to use the per-area method for flow allocation.
  • Each parcel’s flow is assigned to the nearest node (e.g., manhole), which can be automated with spatial SQL queries.

Step 4: Analysis and Comparison with Traditional Methods

  • Even without running simulations, system capacity can be estimated and compared to legacy methods (e.g., Manning’s equation via Cutters formula).
  • SQL queries within ICM enable direct comparison between calculated capacities from both approaches.
  • Typically, ICM estimates show slightly higher capacities due to more detailed calculations.
  • Extended time-series simulations can be run to visualize dynamic results, stress-test the system, and display outputs as maps and graphs (e.g., flooding scenarios, freeboard on manholes).

Decisions

  • No explicit decisions were logged during this meeting.

Open Questions / Follow-Ups

  • No unresolved questions or pending issues were mentioned in the transcript.