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Hydrology Calculators — Earth Science

29 free hydrology & water resources calculators in earth science & geology. Each tool shows step-by-step formulas, worked examples, and detailed explanations to help you get accurate results instantly.

All Hydrology & Water Resources Calculators

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Aquifer Transmissivity Calculator

Calculate aquifer transmissivity with inputs, formulas, and instant results.

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Baseflow Index Calculator

Calculate baseflow index with inputs, formulas, and instant results.

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Catchment Runoff Calculator

Calculate catchment runoff with inputs, formulas, and instant results.

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Drainage Density Calculator

Calculate drainage density with inputs, formulas, and instant results.

Flow Duration Curve Calculator

Calculate flow duration curve with inputs, formulas, and instant results.

Flow Resistance Converter Nf Calculator

Calculate flow resistance converter (n↔f) with inputs, formulas, and instant results.

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Groundwater Flow Velocity Calculator

Calculate groundwater flow velocity with inputs, formulas, and instant results.

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Groundwater Recharge Calculator

Calculate groundwater recharge with inputs, formulas, and instant results.

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Hydraulic Gradient Calculator - Natural Flow

Calculate hydraulic gradient (natural flow) with inputs, formulas, and instant results.

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Hydraulic Radius Calculator

Calculate hydraulic radius with inputs, formulas, and instant results.

Infiltration Capacity Decay Horton Calculator

Calculate infiltration capacity decay (horton) with inputs, formulas, and instant results.

Infiltration Rate Calculator

Calculate infiltration rate with inputs, formulas, and instant results.

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Mannings Equation Natural Channel Calculator

Calculate manning’s equation (natural channel) with inputs, formulas, and instant results.

Pan Evaporation to Lake Evaporation Calculator

Calculate pan evaporation to lake evaporation with inputs, formulas, and instant results.

Peak Discharge Rational Method Calculator

Calculate peak discharge (rational method) with inputs, formulas, and instant results.

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Pumping Well Drawdown Thiem Theis Calculator

Calculate pumping well drawdown (thiem theis) with inputs, formulas, and instant results.

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Recharge Rate From Water Level Decline Calculator

Calculate recharge rate from water level decline with inputs, formulas, and instant results.

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River Discharge Calculator

Calculate river discharge with inputs, formulas, and instant results.

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Runoff Coefficient From Land Use Calculator

Calculate runoff coefficient from land use with inputs, formulas, and instant results.

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Scs Curve Number Calculator

Calculate scs curve number with inputs, formulas, and instant results.

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Sediment Transport Rate Calculator

Calculate sediment transport rate with inputs, formulas, and instant results.

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Storage Coefficient Calculator

Calculate storage coefficient with inputs, formulas, and instant results.

Stream Power Index Calculator

Calculate stream power index with inputs, formulas, and instant results.

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Surface Runoff Coefficient Calculator

Calculate surface runoff coefficient with inputs, formulas, and instant results.

Time of Concentration Calculator - Kirpich Scs

Calculate time of concentration (kirpich scs) with inputs, formulas, and instant results.

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Unit Hydrograph S Curve Calculator

Calculate unit hydrograph s curve with inputs, formulas, and instant results.

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Water Balance Catchment Calculator

Calculate water balance (catchment) with inputs, formulas, and instant results.

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Watershed Area Calculator

Calculate watershed area with inputs, formulas, and instant results.

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Watershed Slope Calculator

Calculate watershed slope with inputs, formulas, and instant results.

About Hydrology & Water Resources Calculators

Our hydrology & water resources calculators in earth science & geology are designed for students, professionals, and anyone who needs quick, accurate results. Every calculator includes the underlying formula, step-by-step solutions, and real-world worked examples so you can understand the math behind the answer.

Whether you need to solve a one-time problem or verify your own calculations, these free tools cover the most common hydrology & water resources scenarios. All results are computed in your browser — no data is sent to any server.

What You Can Calculate

This section includes 29 tools: Aquifer Transmissivity Calculator, Baseflow Index Calculator, Catchment Runoff Calculator, Drainage Density Calculator, Flow Duration Curve Calculator, Flow Resistance Converter Nf Calculator, Groundwater Flow Velocity Calculator, Groundwater Recharge Calculator, and 21 more. Each calculator is free to use with no signup required.