WaterEngineerLabENGINEERING TOOLS & METHODS
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Water engineering / calculation & design

Engineering clarity.
From rainfall to water systems.

Practical calculators and traceable methods for engineers, designers and reviewers working on drainage, hydraulics and water supply.

Calculate peak runoff Explore the tool directory
13 released toolsSI & US unit optionsMethods alongside results
01 / Engineering domains

Start with your water system.

All topic hubs
01 / stormwater

Stormwater Design

Rainfall, runoff, Tc, drainage pipe, detention and site drainage.

6 released tools 02 / open-channel

Open Channel & Culvert Hydraulics

Manning, culvert and grade/energy interpretation.

2 released tools 03 / pipe-pressure

Water Pipe & Pressure

Flow, velocity, diameter, headloss and pressure.

3 released tools 04 / distribution

Water Distribution & Pumping

Network planning, pump duty and scenarios.

2 released tools
02 / Featured calculators

A clear starting point.

Browse released tools
TOOL-003Available

Rational Method Peak Runoff Calculator

Estimate catchment peak runoff from area, rainfall intensity and coefficient.

CalculatorRational MethodPeak flowCatchment
Open calculator
TOOL-007Available

Manning Open Channel Flow Calculator

Calculate steady uniform channel flow from geometry, slope and roughness.

CalculatorManningOpen channelUniform flow
Open calculator
TOOL-010Available

Water Pipe Flow / Velocity / Headloss Calculator

Calculate pipe velocity and friction headloss for a supplied flow.

CalculatorDarcy–WeisbachVelocityHeadloss
Open calculator
03 / Engineering workflows

Move through the design question.

Workflow steps guide navigation. Calculations remain independent; check assumptions before transferring values between tools.

04 / Topic hubs

Understand the method before the number.

Stormwater methods

Rainfall duration, runoff coefficients and peak-flow assumptions.

Hydraulics & energy

Uniform flow, hydraulic grade and the energy balance.

Water supply design

Velocity, friction losses and pressure-head relationships.

05 / Basis for review

See how an answer is reached.

Read our methodology →
01

Traceable methods

Inspect the equation, units and source references next to the calculation.

02

Explicit limitations

Review assumptions and warnings. Preliminary outputs require professional judgment.

03

Visible release status

Available tools are identified in the directory; closed tools remain clearly labelled.

06 / Advanced resources

Reference material for your next decision.

HOW-TO / 01

Calculate Rational Method peak runoff

Formula, unit conversions, worked example, and design limits.

FIELD GUIDE

Reviewable water calculations

How to keep units, assumptions, and limitations visible.

METHOD / 01

Rational Method peak runoff

Understand Q = C × i × A and its applicability.

PLANNING / 02

Compare drainage scenarios

Make preliminary site-design tradeoffs visible.

METHOD / 03

Time of concentration

Review the Kirpich relationship and input guidance.