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Hydrology Simulations

A collection of interactive 3D visualizations and simulations to help you master concepts in hydrology.

Introduction to Hydrology - Theory & Concepts - Water Balance

Understanding the Hydrologic Cycle, Water Balance, and Meteorological Data.

Water Balance Simulator

100 mm
40 mm
20 mm

Resulting Runoff (R)

40 mm

Assuming DeltaS=0\\\\Delta S = 0

Equation:R = P - ET - G
Calculation:40 = 100 - 40 - 20

Precipitation - Theory & Concepts - Areal Precipitation

Forms, measurement, and analysis of precipitation data.

Precipitation - Theory & Concepts - I D F Curve

Forms, measurement, and analysis of precipitation data.

Interactive IDF Curve Simulator

Adjust the parameters to see how they affect the Intensity-Duration-Frequency curves based on the general equation:

i=fracKcdotTx(td+c)ni = \\frac{K \\cdot T^x}{(t_d + c)^n}
1200
0.20
10
0.80
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Hydrologic Losses - Theory & Concepts - Evaporation

Understanding Evaporation, Transpiration, and Infiltration.

Evaporation Rate Simulator

Adjust the environmental variables to see how they impact the daily evaporation rate.

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Hydrologic Losses - Theory & Concepts - Penman Monteith

Understanding Evaporation, Transpiration, and Infiltration.

Evapotranspiration (ET0ET_0) Simulator

Higher temperature increases capacity to hold moisture.

Higher wind speed removes saturated air from the surface.

Lower humidity increases Vapor Pressure Deficit (VPD).

Energy available to convert liquid water to vapor.

Estimated Evapotranspiration (ET0ET_0)

4.25 mm/day

Penman-Monteith Factors:

  • Energy Term: Radiation drives vaporization.
  • Aerodynamic Term: Wind and humidity drive transport.
  • Higher Temp + Wind + Radiation = Higher ET
  • Higher Humidity = Lower ET

Hydrologic Losses - Theory & Concepts - Horton Infiltration

Understanding Evaporation, Transpiration, and Infiltration.

Horton's Infiltration Equation Simulator

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100 mm/hr
15 mm/hr
0.5 /hr

Formula:fp=15+(100−15)e−0.5tf_p = 15 + (100 - 15)e^{-0.5t}

Observe how increasing k causes the infiltration capacity to drop more rapidly to its constant value.

Hydrologic Losses - Theory & Concepts - Phi Index

Understanding Evaporation, Transpiration, and Infiltration.

Streamflow Measurement - Theory & Concepts - Velocity Area

Techniques for measuring stage and discharge in rivers and streams.

Runoff - Theory & Concepts - Hydrograph Components

Catchment characteristics, runoff components, and the Rational Method.

Hydrograph Components Simulator

Adjust the multipliers to see how Overland Flow, Interflow, and Baseflow contribute to the total stream discharge over time. Notice the different response times and durations for each component.

1.0x
1.0x
1.0x
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Runoff - Theory & Concepts - Rational Method Calc

Catchment characteristics, runoff components, and the Rational Method.

Rational Method Calculator

Q = 0.695 m³/s
Peak Discharge
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0.5

0.1 (Parks) to 0.9 (Pavements)

50 mm/hr
10 ha
Formula:
Q=0.278CIAQ = 0.278 C I A
(Note: This simple version assumes A is converted to km² internally for the 0.278 constant)

Runoff - Theory & Concepts - Time Of Concentration

Catchment characteristics, runoff components, and the Rational Method.

Time of Concentration (tct_c) Simulator

Estimated Time of Concentration (tct_c)

23.4 min

Formula:
tc=0.0195⋅L0.77⋅S−0.385t_c = 0.0195 \cdot L^{0.77} \cdot S^{-0.385}

Runoff - Theory & Concepts - Scs Curve Number

Catchment characteristics, runoff components, and the Rational Method.

SCS Curve Number (CN) Method Simulator

Lower CN = Permeable (e.g., woods, sandy soil)
Higher CN = Impermeable (e.g., pavement, clay)

Potential Maximum Retention (S)

84.67 mm

Initial Abstraction (Ia = 0.2S)

16.93 mm

Direct Runoff (Q)

9.29 mm

Water Balance Visualization

Runoff
Initial Abstr.
Retention
Runoff (Q) Initial Abstraction (Ia) Actual Retention

Hydrographs - Theory & Concepts - Baseflow Separation

Analysis of streamflow over time, Unit Hydrographs, and Baseflow Separation.

Hydrographs - Theory & Concepts - Hydrograph Convolution

Analysis of streamflow over time, Unit Hydrographs, and Baseflow Separation.

Hydrograph Convolution (Superposition)

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1 cm
0 cm
0 cm

This simulation demonstrates the Principle of Superposition. The total hydrograph is the sum of the individual hydrographs generated by each rainfall pulse, lagged by their respective start times.

Hydrographs - Theory & Concepts - Unit Hydrograph

Analysis of streamflow over time, Unit Hydrographs, and Baseflow Separation.

Flood Routing - Theory & Concepts - Muskingum Routing

Muskingum Method and Reservoir Routing.

Muskingum Channel Routing Simulation

Adjust the Storage Time Constant (K) and Weighting Factor (x) to see how the flood wave is attenuated and delayed.

C0: 0.0476
C1: 0.4286
C2: 0.5238
ΣC: 1
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Groundwater Hydrology - Theory & Concepts - Well Drawdown

Aquifers, Darcy's Law, and Well Hydraulics.

Statistical Hydrology - Theory & Concepts - Probability

Return Period, Probability, and Frequency Analysis.

Urban Hydrology - Theory & Concepts - Urbanization Impact

Effects of Urbanization and Stormwater Management.

Snow Hydrology - Theory & Concepts

Understanding snow accumulation, Snow Water Equivalent (SWE), and snowmelt modeling.

Degree-Day Snowmelt Simulation

SWE=ds×ρsρwSWE = d_s \times \frac{\rho_s}{\rho_w}
M=15.0 cm/dayM = 15.0 \text{ cm/day}