Flowpath Engineering Portal
Stormwater Catchpit Network Pipe Sizing — NZ Design Tool
Design and verify stormwater catchpit pipe networks using Rational Method runoff calculation and Colebrook-White pipe sizing. Accumulate flows through branching networks and check proportional depths.
What this tool does
Rational Method Flow Calculation
Calculate stormwater runoff using Q = C × I × A with automatic flow accumulation through branching pipe networks.
Colebrook-White Pipe Sizing
Size pipes using the Colebrook-White equation for full-bore gravity flow with automatic selection of the smallest adequate diameter.
Proportional Depth Check
Verify pipes flow at no more than 70% depth using circular pipe partial-flow hydraulic relationships.
Network Flow Accumulation
Define catchpit nodes with upstream/downstream relationships and automatically accumulate flows through the network to the outfall.
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Open Catchpit Network DesignerPart of the Flowpath Engineering suite of free civil engineering tools for New Zealand.