Sub ExportToCAD() Dim ws As Worksheet Set ws = ThisWorkbook.Sheets("Geometry") ws.Range("B2:C100").Copy ' Copy X and Y columns ' Create a text file or simply message box that data is ready MsgBox "Coordinates copied! Paste into AutoCAD command line.", vbInformation End Sub
The spillway doesn't end at the crest. The chute slope changes, boundary layers develop, and air entrainment occurs. An .xls file uses averaged energy equations. It assumes uniform flow velocity immediately after the control section. In reality, the boundary layer grows, and the velocity distribution changes. By the time you reach the stilling basin, your .xls may be off by 15% in conjugate depth calculations.
Use Excel's step-increment functions to generate a dense array of -coordinates (e.g., from -2mnegative 2 m +50mpositive 50 m intervals). Use the WES equations to calculate the matching
Q=C⋅L⋅He1.5cap Q equals cap C center dot cap L center dot cap H sub e to the 1.5 power ogee spillway designxls better
Typically split into an upstream quadrant and a downstream quadrant. The shape is defined relative to the design head ( Hdcap H sub d
Structural and construction considerations
| Feature | Classic Ogee XLS | Modern Script/HEC-RAS | | :--- | :--- | :--- | | | 10 minutes (download & unprotect sheet) | 60 minutes (install software/setup environment) | | Velocity Distribution | Average (assumes hydrostatic) | Detailed (2D/3D mapping) | | Cavitation Risk | Manual lookup (prone to error) | Automatic pressure contour plots | | Air Entrainment | Ignored (assumes 5% freeboard) | Simulated (bulking factor calculated) | | Audit Trail | Difficult (who changed cell B32?) | Git/Version control capable | | Client Confidence | Low ("You used Excel for a dam?") | High ("You ran a 2D unsteady model.") | Sub ExportToCAD() Dim ws As Worksheet Set ws = ThisWorkbook
A comprehensive design spreadsheet typically includes several modules:
The “better” version doesn’t stop at the crest shape. It integrates:
An advanced XLS workbook automates these checks instantly using integrated lookup logic. Engineering Attribute Manual Calculation / Legacy Methods Spreadsheet Modeling (XLS) Dedicated Hydrology Software Very Slow (Hours per iteration) Instantaneous (Sub-second updates) Moderate (Requires re-running scripts) Error Vulnerability High math and interpolation risks Low (Locked formula framework) Low (Black box algorithm) Data Visibility Fragmented across design sheets Completely open math transparently Hidden behind user interfaces Cost & Portability Low software cost but high labor Free templates with basic software Expensive annual licensing 2. Math Behind Ogee Design Automation By the time you reach the stilling basin, your
The downstream profile is defined by the equation: $$X^n = K \cdot H_d \cdot Y$$ Where $n$ and $K$ depend on the upstream slope.
Operational issues and safety
XLS only wins on initial speed. For safety, accuracy, and defensibility, the modern tools win by a landslide.