This guide walks you through your first use of HydraStorm, from loading the plugin in Civil 3D to exporting a completed storm drain analysis. Follow these steps in order to get a working hydraulic model with results you can review and submit.
The samples folder in your install directory contains ready-to-open .hsp projects — sample-guided-tour (a minimal linear run), sample-culvert-crossing, and sample-hydralink-mode (a HydraLink-linked site) — covering the peak-flow, culvert, and HydraLink hydrology modes. Open one via Load (no drawing required) and press F5 to calculate. See the README in that folder for what each sample demonstrates.
Download the HydraStorm installer from bezaleldesignlab.com and run it. Start Civil 3D 2025 or newer; HydraStorm loads automatically and adds a HydraStorm panel to the BDL ribbon tab (the one tab every Bezalel Design Lab product shares, so HydraLink and AutoStyle Pro sit beside it when they are installed). Click the HydraStorm button there, or type HYDRASTORM at the command line, to open the window. The tab comes back on its own after a workspace switch or CUI change. It floats alongside your drawing, so you can keep working in Civil 3D while it is open.
System requirements: Windows 10/11 (64-bit) and Autodesk Civil 3D 2025 or newer.
The first time you open the window, HydraStorm starts a Guided Tour — a spotlighted walkthrough of the interface using the bundled sample-guided-tour project. Replay it any time from Help > Guided Tour.... If your license isn't activated, a lock overlay covers the window until you activate from Help > Account....
In the HydraStorm toolbar, choose your pipe network from the Network dropdown. This reads all Civil 3D Pipe Network objects in the current drawing, along with pipe and structure geometry, inverts, sizes, part families, and part descriptions from the selected network.
If you modify pipes or structures in Civil 3D on the network you already have open, use the Refresh from CAD toolbar button (it lights up with a warning glyph when it detects an external change) rather than closing and reopening — see Refresh from Civil 3D. The same button re-reads the drawing’s network list, so a brand-new network added to the drawing appears in the Network dropdown after a refresh.

HydraStorm operates on one pipe network at a time. If your drawing contains multiple networks (e.g., separate storm systems), select each one individually to analyze it.
Before configuring hydrology, it's worth checking both items on the toolbar's Drawing menu: Network Issues (badged with a count when it finds something — orphaned basins, broken bypass targets, pass-through ponds, and other connectivity problems; rows click-navigate to the offending structure) and Clean Up Drawing (a suggest-and-confirm hub for drafting defects: reversed or zero-length pipes, missing reference alignments, alignments with no assigned run, and structure rims). Neither is required to proceed, but catching a drafting defect here is cheaper than chasing its symptom later in the results grid.
Click the Settings button in the toolbar to open the Project Settings dialog. Before running your first calculation, review these key settings:
The design standard (junction loss library, e.g., HEC-22, iSWM/NCTCOG, or a custom standard) is selected separately, from the Tables > Minor Losses... dialog. If the standard includes design criteria, you'll be prompted to apply municipality-specific defaults.

Each alignment in your pipe network is classified as one of three design types:
Set alignment types from Tables > Alignment Types... (Project Settings has no alignment-type controls of its own). If your network is all storm drain pipes, you can skip this step.
Enter design flows for each structure. The method depends on the hydrology mode you selected:
.hyd or .hlresults file in Project Settings > Hydrology. HydraStorm automatically matches HydraLink basins and junctions to your pipe network structures by name, then by spatial proximity.See Hydrology Modes for a detailed explanation of each mode.
Open Tables > Minor Losses.... Each structure in your network needs a junction loss type that determines how energy losses are calculated at that node.

Angles in the Minor Losses Table are the deflection from straight, the way a fitting is named: a "45 Degree Bend" is 45. A standard fitting class in the Civil 3D part description is auto-detected directly into the structure's angle at import — wye/lateral descriptions land on the Lateral Angle field, not the trunk. Angles measured from the actual pipe geometry are only ever suggested, within 5° of a standard fitting (22.5/30/45/60), never applied automatically; accept them from the Angle Suggestion badge in the Minor Losses Table. A bend, wye, or direction-change manhole with no angle entered shows its Angle cell in orange until you confirm one. (The loss-library equations themselves still evaluate the HEC-22 θ, 180° = straight — the table converts at its edge.)
If your project requires inlet capacity analysis, switch to the Inlet tab and click Library... to select an inlet library (e.g., HEC-22, iSWM, or municipality-specific). Then, for each inlet:
Press F5 (there is no dedicated Calculate button; results also refresh automatically a moment after you finish editing a property). HydraStorm runs the full analysis in order:
Results appear immediately in the results grid, and the profile view updates to show the computed HGL and EGL lines.

Examine the results grid for any issues. HydraStorm tracks compliance with color-coded indicators:
The Comply column shows a score like "4/6" (4 of 6 checks passed). Hover for details on each check. If a failure is intentional, right-click the pipe and choose Acknowledge Check Failures....
In the profile view, toggle these overlays to visualize the hydraulic analysis:
Adjust pipe parameters to resolve compliance issues. Inverts, size, slope, and Manning's n are edited directly in the results grid; shape, part family, and junction loss type are edited in the property panel next to the profile. The profile and calculations update live as you make changes.
Use the editing tools for efficient adjustments:
Ctrl+Shift+R) — Shift both inverts uniformly (preserves slope)Ctrl+Shift+L) — Apply a specific slope with anchor selectionCtrl+M) — Set a continuous slope across multiple selected pipesClick Auto (in the property panel) to let HydraStorm suggest pipe sizes that satisfy your design constraints. Auto Design runs its own calculation internally, so there's no need to press F5 first. The sizing engine selects the smallest standard pipe size from the active parts list that meets capacity, velocity, and HGL cover requirements. It works upstream from the outfall and backtracks downstream when HGL violations are detected. Sizing applies to the alignment currently shown in the profile view; pipes on other alignments keep their sizes and act as fixed hydraulic context.
Two dialogs may appear before sizing starts: a scope prompt if you have several pipes selected (size just the selection, or the whole run), and a start-elevation prompt letting you set or accept the invert at each outfall/scope tie-in the walk anchors from. Neither is shown when it has nothing to ask — e.g. no multi-pipe selection, or Auto Design Grades is set to Hold Existing Grades.
Review the suggested sizes, then click Apply (in the property panel) to accept or Discard to revert. See Auto Design for details.
When you are satisfied with your design, click Apply (pinned at the bottom of the property panel) to write all edits back to the Civil 3D pipe network objects. This updates pipe invert elevations, pipe sizes, and Manning's n values, along with anything else you changed in the session: part family/size swaps, structure rim elevations, junction loss values (Pipe.JunctionLoss), and any run-aware renames from Drawing > Rename Parts by Run....
If you need to undo your changes, click Discard to revert to the last applied snapshot.

HydraStorm uses an Edit Session pattern: all your changes are made to a working copy. Nothing is written to Civil 3D until you explicitly click Apply. This means you can freely experiment without risk to your drawing.
Once your design is finalized and applied to Civil 3D, open the Output ▾ menu in the toolbar:
See Profiles & Labels for details on configuring label styles and profile view options.
From the Output ▾ menu, click Export > Excel Workbook... to write the full calculation workbook for verification or submittal — storm drain, inlet, culvert and compliance sheets, with live formulas a reviewer can follow. (The older CSV dumps were removed in September 2026; save a sheet as CSV from Excel if another tool needs one.)
See Export for details on the export format and customization options.
F5 = Calculate, Ctrl+Z = Undo, Ctrl+S = Quick Save, Ctrl+F = Fit Profile, Arrow keys = navigate pipes.hsp) store all your settings, flows, and loss type assignments independently from the Civil 3D drawing.