Culvert Studio
The culvert sizing calculator and hydraulic design tool built for Canadian engineers.
Updated August 7, 2026Features
Culvert Sizing
Rational Method + Manning's equation. Get a recommended culvert size, design flow, and velocity in seconds.
Offline Canadian IDF Data
565 IDF weather stations across all 13 provinces and territories. 28,900+ data points, fully offline at the job site.
Control Analysis
Inlet/outlet control, performance curves, headwater checks, and multi-barrel, orifice, weir, and tidal-tailwater analysis.
2D & 3D Visualization
See your culvert profile in an interactive 2D/3D viewer with a design-flow animation and performance curve.
Compliance Checks
Velocity, HW/D, and design checks against NBC 2020 and CSA standards for Canadian infrastructure projects.
AI Explainer & Export
Ask the AI assistant to explain any result step by step. Save projects and export reports as PDF or GeoJSON/KML.
Culvert Sizing FAQ
How do I calculate what size culvert I need?
Use the Rational Method (Q = CiA) to estimate peak runoff, then apply Manning's equation to size the culvert for that flow given your slope and pipe material. Culvert Studio automates both steps and returns a recommended diameter, design flow, and velocity.
What are standard culvert sizes?
Common circular culvert diameters range from 300 mm to 3000 mm (1 to 10 ft) in standard increments. Box culverts are specified by span x rise. Culvert Studio recommends the nearest standard size.
How much water can a 36 inch culvert handle?
It depends on slope, material, and allowable headwater. As a rough guide, a 900 mm concrete culvert at a typical 1% slope can pass roughly 2 to 4 cubic metres per second. Culvert Studio computes the exact capacity for your site.
How deep do culverts need to be?
Cover depth depends on the loads above. For highway loads, typical cover is 0.3 to 1.2 metres; always confirm against NBC 2020 and the applicable provincial or municipal standards.
What are the three types of culverts?
Pipe (circular), box (rectangular), and arch culverts. The right choice depends on flow, headroom, and site constraints.
What is the formula for calculating stormwater volume?
Peak runoff uses the Rational Method: Q = CiA, where C is the runoff coefficient, i is rainfall intensity, and A is the drainage area. Volume is flow multiplied by duration. Culvert Studio applies this with real IDF data.
What software can I use to calculate stormwater?
Culvert Studio is purpose-built for culvert and drainage design with offline Canadian IDF data, control analysis, and 3D visualization. Other options include HY-8 and CulvertMaster.
Built With
Design With Confidence
Professional culvert sizing with offline Canadian IDF data. Free for iOS and Android.
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