Remember the two equations?
Typing these into an XLS with a 0.1m step size gives you instant coordinates for formwork fabrication. No manual table lookups, no rounding errors.
Many junior engineers forget that ogee crests have a complex upstream quadrant (Elliptical or Circular transitions). Manual scaling from a scanned PDF graph introduces "digitization error."
The spillway is useless without a safe energy dissipator. We need to calculate the Tolerable Tailwater. ogee spillway designxls better
Inputs:
Calculations:
Conjugate Depth ($d_2$ - Hydraulic Jump): Remember the two equations
Tailwater Requirement:
The constants ($n$ and $K$) change if the upstream face is sloped.
A standard .xls assumes you are building exactly to the WES profile for the design head. But if your actual operating head ($H_e$) exceeds the design head ($H_d$), negative pressures (cavitation risk) develop on the crest. Excel cannot simulate the dynamic pressure distribution along the curved profile. You need CFD or at least a numerical panel method—something that requires iterative matrix solving, which Excel handles poorly. Typing these into an XLS with a 0
An ogee spillway is a overflow structure shaped like an inverted “S” (an ogee curve). Its profile ideally matches the lower nappe of a water jet flowing over a sharp-crested weir. When designed correctly, it discharges water efficiently with minimal negative pressure, reducing cavitation risk and structural stress.
Designing one requires solving the crest profile equation (typically the USACE or WES standard form):
[ y = \fracx^1.852 \cdot H_d^0.85 ]
Where ( H_d ) is the design head. The complexity arises from:
Old spreadsheets crashed if you entered feet instead of meters. The improved version includes: