Watercalcs
Estimates only — verify before relying on results. Terms of Use
v3.3
Min
Avg
Max
Use for calcs:
°C
How this works

The model works backwards from a set final discharge level. This is normally a treated water tank top water level (TWL), a reservoir level, or a receiving water level.

Once that anchor is set, add components to build up the whole treatment train — pipes, channels, weirs, baffles, filters, membranes, screens, pumps, the lot. Each card you add sits further upstream than the one below it.

Where there are multiple process trains you only need to work backwards through one. Components have a streams field so you can say "this card represents 1 of 4 filters" and the section flow scales accordingly.

Add as much detail as you can — pipe lengths, fitting counts, channel FFLs, weir crest levels — and the result gets more accurate. Each card carries a live diagnostic showing velocity, head loss, key levels, and any sanity warnings.

If you want a worked example, hit Use demo data below.

Discharge anchor

The fixed downstream water level the whole profile is computed against. Usually a treated water tank, reservoir, or receiving water TWL.
m RL

Component chain

Hit the blue + Insert component button to drop a new card in. Each new card represents whatever sits upstream of the one below it.
Water level required at the start of the chain:
About this tab

A row-by-row look at every component in the chain — the calculated water level at each one, alongside whatever reference levels you've set (weir crests, channel FFLs, filter floors, tank TWLs).

The number at the start of the chain is the water level your source would need to deliver to push the design flow through everything downstream. If your real source can't reach it, either the plant is losing too much head somewhere or you need a pump in the chain.

Profile summary

About this tab

A visual of the hydraulic grade line through the plant — water level at every component, from the source side on the left to the discharge on the right. Components are evenly spaced; only the order matters, not the distance between them.

A step down in the line means a pump or membrane suction is restoring head at that point. A step up means head is being consumed — friction in a pipe, a weir, a filter, a TMP drop, that sort of thing.

Hydraulic Grade Line

How exporting works

Pick which of the other tabs (Build, Levels, Profile) you want included, then download as either a PDF or a CSV. The tab selection applies to both.

For PDF: your browser's print dialog opens — choose "Save as PDF" as the destination. To get a clean output with no URL/page-number bar, untick "Headers and footers" in the print dialog options.

Save state writes a JSON file containing every input and the current results. Reload it later (or share it with a colleague) and the plant is restored exactly.

What to include

Pick the tabs you want in the export. The selection applies to both PDF and CSV.

PDF

Opens your browser's print dialog. Choose Save as PDF as the destination. For a clean output, untick Headers and footers in the dialog's More settings.

CSV

Spreadsheet-friendly export of the selected tabs.

Save state (JSON)

Writes every input and the current results to a JSON file. Reload it later (or share it) to restore the exact same plant.

Load state (JSON)

Upload a previously-saved JSON file to restore.

Clear all data

Resets the tool to defaults. Cannot be undone.

About this tool

Purpose

A gravity hydraulic profile model for water treatment plants. You set a downstream discharge level, build the treatment train upstream of it, and the tool computes the water level needed at every point — pipes, channels, weirs, baffles, filters, membranes, pumps, everything.

Basis of calculation

Assumptions

Limitations

Public-domain references

Settings

Display

Reference library

Roughness, Manning, K-factors and filter-media defaults. Edit values to suit your local conventions.

Reset

Clear stored state and start fresh. This does not affect any JSON file you've already saved.

Library