// multi-utility computation suite · offline · instant · precise
┌──────────────────────────┐
│ [c] calcalyst_ │
│ computation suite │
└──────────────────────────┘
// select a module to initialize
/ search↵ open firstesc close
// adsenseEMPTY_LEADER_SLOT728×90
// keyboard shortcuts
/focus search
Escclear search · close calc
Enteropen first result
↑↓navigate list
?toggle this panel
// adsenseMOBILE_ANCHOR_SLOT320×50
// keyboard_shortcuts
/focus search
↑↓navigate module list
Enter
open first result from search
open highlighted
compute when module is open
compute when focused in a field
Escclose module · clear selection
⌫
eng.storm-drain-design Calculator
Calculates storm drain capacity and pipe sizing from design flow and Manning's equation for circular pipes flowing full. Storm sewers are designed to flow full at the design storm (typically 10-year return period) — inlet efficiency and surcharging must also be evaluated.
Inputs
Catchment Area Ha
Two-dimensional surface extent (m²). For complex shapes, break into simpler sub-shapes and sum.
Runoff Coefficient
Reference formula or conversion factor shown for context.
Rainfall Intensity Mm Hr
Reference formula or conversion factor shown for context.
Design Return Period Yr
Time for one complete cycle (s). Period = 1 / frequency. A 50 Hz signal has a 20 ms period.
Results
design flow rate Q (m³/s)
Flow rate Q — the volume of fluid passing a point per unit time.
flow rate (L/s)
The value at the specified point or condition.
pipe diameter estimate (m)
The computed diameter -- twice the radius.
Q = C × I × A
Reference formula or conversion factor shown for context.
runoff coefficient
Sample size or count used in the calculation.
velocity check (m/s)
A pass/fail verification against the applicable code, standard, or threshold.