Manning's equation for open channel flow, normal depth and critical depth, the Froude number and flow regimes, channel design for a target capacity, and inlet-control versus outlet-control culvert hydraulics.
Open channel flow behaves fundamentally differently from pressurized pipe flow because depth itself is a variable the flow adjusts to, not a fixed boundary — and Manning's equation is the workhorse relationship that connects channel geometry, roughness, and slope to velocity and discharge. This module builds Manning's equation from its variables through a fully worked normal-depth solve for a trapezoidal channel, develops critical depth and the Froude number as the tools for classifying subcritical versus supercritical flow, and closes with the two-condition inlet-control/outlet-control framework every culvert design has to check.
By the end of this module you should be able to explain why a culvert cannot simply be assumed to be inlet-controlled from its shape alone, and why capacity and permissible velocity are two independent checks a channel design has to satisfy separately — concepts Module 9's pipe network content and Module 3's stormwater content both build directly on.