Drainage Design
Size the drainage correctly the first time. Catchment estimation, peak flow and hydraulic capacity give you the required drain section and culvert opening. Structural design of box culverts is done in Box Culvert Design (03.03), part of Road Design and Estimation; it is not part of this module.
Size drains and culvert openings from catchment and peak flow — hydraulic sizing only.
Size drains and culvert openings from catchment and peak flow — hydraulic sizing only.
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Built for the real job.
Catchment & runoff
Rational and SCS methods with local rainfall intensity data.
Hydraulic sizing
Inlet and outlet control checks to fix the required culvert opening size.
Channel & drain design
Manning's flow for lined and unlined drains, with velocity checks.
Levels & outfalls
Invert levels, gradients and outfall points taken straight from the terrain model.
Size a drain or culvert opening.
Rational method peak flow, then Manning's sizing for the required opening. Hydraulic sizing only — structural culvert design is a separate application.
Indicative sample — a simplified calculator, not the module. The module runs on your own data, and the figures and standards it applies are the ones you enter.
Four steps, start to drawing.
- 01Delineate the catchment and set the return period.
- 02Compute the design discharge.
- 03Select and size the drain section or culvert opening.
- 04Export the hydraulic sizing sheet with invert levels.
What you take away.
- →Peak flow calculation
- →Culvert opening sizing sheet
- →Drain section design
- →Invert level & gradient schedule
BESPA Expert Systems is suitable for the preliminary design and feasibility study phase of civil infrastructure projects. Outputs are engineering aids, not certified designs: a qualified professional engineer must check and sign off any output before it is issued for construction. This module performs hydraulic sizing only. Structural design of reinforced concrete box culverts — member thickness, reinforcement, headwalls, wingwalls and outlet protection — is done in Box Culvert Design (AASHTO), module 03.03 of Road Design and Estimation. It is not included in Digital Terrain Modelling.
Contouring
Generate precise contour maps from survey data. Read the land before you shape it.
Land Preparation
Compute cut and fill against a platform level — or find the level that balances them.
Estate Layout
Fit plots and internal roads to a surveyed boundary, on your own terrain model.
Questions on drainage design?
Write to Dr. Kwasi Osafo Ampadu, or use the feedback form on the home page.
Emailinfo@bespa.online