Connected drainage profile
Multiple Drain Run Fall Calculator for Connected Pipe Segments
Calculate the fall of up to five connected drainage segments when each run can have a different length and slope. The result builds a cumulative profile instead of treating the route as one average slope.
Drain segment inputs
Segment 1
Segment 2
Segment 3
Segment 4
Segment 5
Set unused segments to zero. Each active segment is calculated independently, then added to the cumulative fall.
Drainage profile result
Total cumulative fall
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—
—Total run
—Equivalent average slope
—Active segments
—Total fall
| Segment | Run | Slope | Fall | Cumulative fall |
|---|
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Why segment-by-segment fall matters
A drainage route can change slope at fittings, structures or grade breaks. Applying one average slope may hide those changes. This planner keeps each segment visible and calculates the actual fall contribution from each run.
Segment fall = segment run × (slope ÷ 100)
Total fall = sum of all segment falls
Equivalent average slope = total fall ÷ total run
Total fall = sum of all segment falls
Equivalent average slope = total fall ÷ total run
Using the result on drawings
The cumulative fall can be used as an arithmetic check between a starting reference level and downstream level. It does not replace a surveyed profile or establish required drainage grades.
Worked example
8 m × 2% = 0.160 m
6 m × 1.5% = 0.090 m
5 m × 2% = 0.100 m
Total fall = 0.350 m
6 m × 1.5% = 0.090 m
5 m × 2% = 0.100 m
Total fall = 0.350 m
Frequently Asked Questions
Can slopes differ between segments?
Yes.
Can I use fewer than five segments?
Yes. Leave unused segments at zero.
Does this calculate invert levels?
It calculates fall. Combine it with a known starting invert to determine a downstream level.