Flowpath Engineering Portal
Pipe Flow Calculator — Hydraulic Grade Line Analysis
Calculate hydraulic grade lines, pipe capacities, and flow velocities for NZ stormwater and wastewater reticulation design.
What this tool does
Hydraulic Grade Line (HGL)
Plot the hydraulic grade line through a pipe network to verify adequate freeboard and identify surcharge conditions at each manhole.
Pipe Capacity Analysis
Determine the full-bore and part-full capacity of circular pipes using Manning's equation for a range of NZ-standard pipe materials and sizes.
Flow Velocity Checks
Verify that flow velocities meet minimum self-cleansing requirements and do not exceed maximum limits for the selected pipe material.
Multiple Pipe Runs
Analyse series of connected pipe segments with varying grades, diameters, and materials in a single calculation sheet.
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Open Pipe Flow CalculatorPart of the Flowpath Engineering suite of free civil engineering tools for New Zealand.