Project Settings

The Project Settings dialog configures calculation methodology, hydrology, design criteria, and output options for your project. Open it from the Settings button in the toolbar.

Project Tab

Basic project identification. These values appear on exported reports.

Setting	Description
Project Name	Name of the project
Job Number	Project or job number for tracking
Engineer	Engineer of record

Calculation Tab

Controls the hydraulic calculation engine, design constraints, and pipe design criteria.

Friction Method

Setting	Description
Friction Method	Manning's equation (default) or Hazen-Williams equation. Applies project-wide.
Default Manning's n	Default roughness coefficient for new pipes (default: 0.013). Can be overridden per pipe.
Default Hazen-Williams C	Default smoothness coefficient when Hazen-Williams is selected (default: 150).

Tailwater

Setting	Description
Default Tailwater Method	How to compute the downstream boundary condition at outfalls: Critical Depth Average — (Dc + D) / 2. Common conservative default. Crown — Tailwater at the pipe crown (invert + rise). Most conservative. Normal Depth — Manning's uniform flow depth at the outfall slope. Individual outfalls can override this with a manual tailwater elevation.

Design Constraints

Setting	Default	Description
Minimum Pipe Diameter	0.5 ft (6")	Smallest allowable pipe size for Auto Design.
Minimum Pipe Slope	0.005 ft/ft	Minimum allowable slope. Pipes below this trigger a warning.
Maximum Full-Flow Velocity	10.0 ft/s	Pipes exceeding this velocity trigger a compliance warning.
Minimum Full-Flow Velocity	2.0 ft/s	Pipes below this velocity trigger a compliance warning (self-cleaning velocity).
Minimum Pipe Cover	2.0 ft	Minimum clearance from ground to pipe crown.
Maximum Pipe Cover	20.0 ft	Maximum depth from ground to pipe crown.
Minimum Structure Depth	4.0 ft	Minimum depth from rim to lowest connected pipe invert at each junction.
Structure Drop	0.1 ft	Default drop applied at each junction between connected pipes (used by the Inverts match criterion).
HGL Cover (Design)	1.0 ft	Required clearance from the hydraulic grade line to ground/rim for the design storm.
HGL Cover (Check)	0.0 ft	Required HGL clearance for the check storm. Zero means the HGL can reach the rim.

Alignment Configuration

Setting	Description
Require Alignments	When enabled, pipes must be assigned to an alignment to be included in calculations.
Accumulate Flows	When enabled (default), flows accumulate downstream through junctions. Disable for lateral-only analysis where each pipe carries only its local flow.
Alignment Sort Order	Alphabetical (by name) or Hydrologic (trunks first, then laterals downstream-to-upstream).
Alignment Design Types	Classify each alignment as Storm Drain (standard HGL), Culvert (HDS-5 headwater), or None (excluded). Also configurable from the Alignment Types editor in the Tables menu.

Compliance Checks

Below the Design Constraints table, every design-criteria check (velocity, cover, HGL clearance, etc.) has its own Enabled / Disabled toggle. Disabling a check removes it entirely from the Comply column — its rows in the results grid no longer factor it into the pass/total score, and its per-pipe warnings are suppressed. This is a project-wide switch; for a one-off accepted violation on a specific pipe, use the per-pipe Acknowledge Check Failures... right-click action instead, which preserves an audit trail. See Compliance Checking.

Auto Design & Matching Defaults

Setting	Description
Auto Design Size Changes	How Auto Design handles a mid-run size increase: Never split the pipe, Prompt before splitting, or split Automatically at a size-change null structure.
Min Split Leg Length (ft)	Shortest leg Auto Design will create when splitting a pipe for a size change.
Split Station Rounding (ft)	Station increment new split points are rounded to.
Match Crowns at Size Change	Yes/No — whether the Crowns match criterion is preferred at a pipe-size transition.
Fitting Keywords	Comma-separated Civil 3D part-description keywords (e.g. "Fitting", "Coupling") that identify structures excluded from the minimum structure depth check. Remembered as your default for new projects.
Structure Drop (ft)	Default drop applied at each junction between connected pipes (used by the Inverts match criterion).
Ignore Null Structure Drop	Yes/No — when Yes, the Structure Drop is not applied at null (pipe-to-pipe) structures.
Default Match Criteria	Default structure transition criterion (Inverts, Centerlines, or Crowns) for new multi-pipe slope operations.
Auto-Update K Values	Yes/No — whether junction Kj values recompute automatically as geometry changes.
Alignment Sort Order	Alphabetical (by name) or Hydrologic (trunks first, then laterals downstream-to-upstream). Also listed under Alignment Configuration above.
Merge Splice Rows	Yes/No — when Yes, pipe-splice reaches (several real pipes shown as one continuous run) are merged into a single read-only row in the results grid.

Design Standard (Not in This Dialog)

The active design standard (junction loss library) is not selected in Project Settings — it's chosen from the Design standard dropdown at the top of Tables > Structures.... The Calculation tab above only reminds you of this ("Junction losses are driven by the selected design standard. Use the Structures dialog to choose or edit it."). Built-in standards include:

• User Starter — Generic loss types with simple K expressions. Good starting point for custom standards.
• HEC-22 — HEC-22 4th Edition standard types, using the 3-step access hole energy loss method for manholes.
• iSWM / NCTCOG — NCTCOG iSWM 2014 types, using the HEC-22 2nd Edition compound K method for manholes.

When a standard includes design criteria (municipality-specific defaults for storm periods, velocity limits, cover, etc.), HydraStorm prompts you with a checklist showing which settings differ from your current project. Accept or decline each recommendation individually.

Hydrology Tab

Detailed on the Hydrology Modes and Storm Events pages. The tab has two sub-tabs, Storm Events and IDF Curves, below the hydrology mode selector.

Hydrology Mode

Always visible at the top of the tab, as radio buttons:

Mode	Description
Peak Flows Only	Enter Q (cfs) directly at each node. No rational method.
HydraLink	Import flows from a HydraLink project file (.hyd or .hlresults). Selecting this mode reveals a HydraLink Integration section on the Storm Events sub-tab (file path/browse/reload, plan and primary/secondary storm selection, spatial match radius, and a flow-assignment review grid).
Parcels	Read drainage area from Civil 3D parcels, C and Tc from User-Defined Properties.
Manual	Enter area, C, and Tc per node for rational method calculation.

Storm Events Sub-Tab

Storm return periods are configured as a small per-module grid rather than a single design/check pair — you add as many storm events as your project needs and assign each one a role. There is a separate grid for each module:

Column	Description
Storm	The return period label (e.g. "10 yr"), read-only once added.
Role	Design, Check, or Unused for that module.
Cf	Storm frequency adjustment factor — multiplies the runoff coefficient C for that storm's rational-method flows when "Apply Storm Frequency Adjustment Factor (Cf)" is checked below the grids.
Inlet (storm drain grid only)	Checkbox — when checked, this storm's captured inlet flows feed into the storm drain HGL calculation for that storm (replaces a separate design/check toggle; it's set per storm row).

Use the return-period combo box and + Add button beneath each grid to add a new storm to that module; click the x on a row to remove it. The three grids are labeled STORM DRAIN, CULVERTS, and (only when the inlet module is enabled) INLETS — each module's storms, roles, and Cf values are independent, so a municipality that sizes pipes for 10-year but checks inlets against 100-year spread just adds both return periods with the matching roles per grid.

When a Check role is assigned in the storm drain grid, a Sizing Storm radio (Design / Check) appears, controlling which storm Auto Design uses for pipe sizing.

Rational Method Defaults (hidden in Peak Flows Only mode)

Setting	Default	Description
Enable Travel Time Adjustment	Off	Accumulate travel time through pipes (pipe length / full-pipe velocity) for Tc computation.
Default Inlet Time	10 min	Time of concentration for overland flow to reach the first inlet.
Default Runoff Coefficient C	0.70	Default runoff coefficient applied to new nodes.
Apply Rational Unit Conversion Factor	Off	When checked, multiplies peak flow by the Conversion Factor (default 1.008) that converts acre·in/hr to cfs. Most engineers leave this off since the bias is <1%.

IDF Curves Sub-Tab (hidden in Peak Flows Only mode)

Configures rainfall intensity-duration-frequency data for the rational method:

• Import controls (hidden in HydraLink mode, where IDF comes from the linked file) — Latitude/Longitude fields with a Pick Point button (samples a point in the drawing), Fetch NOAA Atlas 14, and Import CSV.
• Interpolation Method — radio buttons: Log-Log (log-log interpolation on the intensity table; standard for Atlas 14 data), Linear (linear interpolation on the table), or E/B/D Coefficients (evaluates i = E / (tc + B)^D).
• Duration / Intensity Table — editable grid of duration vs. intensity, with a column per active module/storm combination (design, check, culvert design/check, inlet design as applicable).
• E/B/D Coefficients section (shown when Coefficients mode is selected) — editable E, B, D per storm with an R² fit-quality readout, and a Generate from Table button that fits coefficients from the table above (durations up to 2 hours).
• IDF Curve chart — a log-log intensity-duration chart reflecting the current table/coefficients and interpolation method.

See the IDF Data page for more detail on each source.

Output Tab

Profiles

Setting	Description
Storms to Profile	Design, Check, or Both. Controls which HGL profiles are created in Civil 3D.

Labels

Four label style slots, each with a dropdown to select from available Civil 3D label styles:

Slot	Purpose
Pipe Full Flow	Label style for pipes at or above capacity.
Pipe Partial Flow	Label style for pipes flowing partially full.
Structure Style 1	Primary structure label style.
Structure Style 2	Secondary structure label style.