Drawdown Calculator

✖Discharge is the volumetric flow rate of water that is transported through a given cross-sectional area. It includes any suspended solids, dissolved chemicals, or biologic material.ⓘ Discharge [Q]			+10% -10%
✖Transmissivity is the rate at which groundwater flows horizontally through an aquifer or the degree to which a medium allows something, in particular electromagnetic radiation, to pass through it.ⓘ Transmissivity [T]			+10% -10%
✖Time Period is the duration over which groundwater observations, measurements, or modeling simulations are conducted. It can vary from short-term periods to long-term periods.ⓘ Time Period [t]			+10% -10%
✖Distance from Pumping Well is the horizontal distance between a specific point in an aquifer and the location of a pumping well. It influences the behavior of groundwater flow.ⓘ Distance from Pumping Well [r]			+10% -10%
✖Storage Coefficient is the volume of water released from storage per unit decline in hydraulic head in the aquifer, per unit area of the aquifer.ⓘ Storage Coefficient [S]			+10% -10%

✖Total Drawdown is the reduction in hydraulic head observed at a well in an aquifer, typically due to pumping a well as part of an aquifer test or well test.ⓘ Drawdown [s_t]

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Drawdown Solution

STEP 0: Pre-Calculation Summary

Formula Used

Total Drawdown = (Discharge/(4*pi*Transmissivity))*ln((2.2*Transmissivity*Time Period)/(Distance from Pumping Well^2*Storage Coefficient))
s_t = (Q/(4*pi*T))*ln((2.2*T*t)/(r^2*S))
This formula uses 1 Constants, 1 Functions, 6 Variables

Constants Used

pi - Archimedes' constant Value Taken As 3.14159265358979323846264338327950288

Functions Used

ln - The natural logarithm, also known as the logarithm to the base e, is the inverse function of the natural exponential function., ln(Number)

Variables Used

Total Drawdown - (Measured in Meter) - Total Drawdown is the reduction in hydraulic head observed at a well in an aquifer, typically due to pumping a well as part of an aquifer test or well test.
Discharge - (Measured in Cubic Meter per Second) - Discharge is the volumetric flow rate of water that is transported through a given cross-sectional area. It includes any suspended solids, dissolved chemicals, or biologic material.
Transmissivity - (Measured in Square Meter per Second) - Transmissivity is the rate at which groundwater flows horizontally through an aquifer or the degree to which a medium allows something, in particular electromagnetic radiation, to pass through it.
Time Period - (Measured in Second) - Time Period is the duration over which groundwater observations, measurements, or modeling simulations are conducted. It can vary from short-term periods to long-term periods.
Distance from Pumping Well - (Measured in Meter) - Distance from Pumping Well is the horizontal distance between a specific point in an aquifer and the location of a pumping well. It influences the behavior of groundwater flow.
Storage Coefficient - Storage Coefficient is the volume of water released from storage per unit decline in hydraulic head in the aquifer, per unit area of the aquifer.

STEP 1: Convert Input(s) to Base Unit

Discharge: 3 Cubic Meter per Second --> 3 Cubic Meter per Second No Conversion Required
Transmissivity: 11 Square Meter per Second --> 11 Square Meter per Second No Conversion Required
Time Period: 130 Second --> 130 Second No Conversion Required
Distance from Pumping Well: 3 Meter --> 3 Meter No Conversion Required
Storage Coefficient: 85 --> No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

s_t = (Q/(4*pi*T))*ln((2.2*T*t)/(r^2*S)) --> (3/(4*pi*11))*ln((2.2*11*130)/(3^2*85))

Evaluating ... ...

s_t = 0.0306882109079858

STEP 3: Convert Result to Output's Unit

0.0306882109079858 Meter --> No Conversion Required

FINAL ANSWER

0.0306882109079858 ≈ 0.030688 Meter <-- Total Drawdown

(Calculation completed in 00.004 seconds)

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Coorg Institute of Technology (CIT), Coorg

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< Unsteady Flow in a Confined Aquifer Calculators

Drawdown

LaTeX Go Total Drawdown = (Discharge/(4*pi*Transmissivity))*ln((2.2*Transmissivity*Time Period)/(Distance from Pumping Well^2*Storage Coefficient))

Drawdown at Time Interval 't1'

LaTeX Go Drawdown at Time Interval t1 = Drawdown at Time Interval t2-((Discharge/(4*pi*Transmissivity))*ln(Time of Drawdown (t2)/Time of Drawdown (t1)))

Drawdown at Time Interval 't2'

LaTeX Go Drawdown at Time Interval t2 = ((Discharge/(4*pi*Transmissivity))*ln(Time of Drawdown (t2)/Time of Drawdown (t1)))+Drawdown at Time Interval t1

Equation for Storage Coefficient

LaTeX Go Storage Coefficient = 2.25*Transmissivity*Starting Time/Distance from Pumping Well^2

Drawdown Formula

LaTeX Go

Total Drawdown = (Discharge/(4*pi*Transmissivity))*ln((2.2*Transmissivity*Time Period)/(Distance from Pumping Well^2*Storage Coefficient))
s_t = (Q/(4*pi*T))*ln((2.2*T*t)/(r^2*S))

What is Discharge in Hydrology?

Discharge is the volumetric flow rate of water that is transported through a given cross-sectional area. It includes any suspended solids, dissolved chemicals, or biologic material in addition to the water itself.

How to Calculate Drawdown?

Drawdown calculator uses Total Drawdown = (Discharge/(4*pi*Transmissivity))*ln((2.2*Transmissivity*Time Period)/(Distance from Pumping Well^2*Storage Coefficient)) to calculate the Total Drawdown, The Drawdown formula is defined as the change in groundwater level due to an applied stress, caused by events such as: Pumping from a well, pumping from a neighboring well. Time is derived on Semi-log sheet plotted against drawdown. Total Drawdown is denoted by s_t symbol.

How to calculate Drawdown using this online calculator? To use this online calculator for Drawdown, enter Discharge (Q), Transmissivity (T), Time Period (t), Distance from Pumping Well (r) & Storage Coefficient (S) and hit the calculate button. Here is how the Drawdown calculation can be explained with given input values -> -0.001136 = (3/(4*pi*11))*ln((2.2*11*130)/(3^2*85)).

FAQ

What is Drawdown?

The Drawdown formula is defined as the change in groundwater level due to an applied stress, caused by events such as: Pumping from a well, pumping from a neighboring well. Time is derived on Semi-log sheet plotted against drawdown and is represented as s_t = (Q/(4*pi*T))*ln((2.2*T*t)/(r^2*S)) or Total Drawdown = (Discharge/(4*pi*Transmissivity))*ln((2.2*Transmissivity*Time Period)/(Distance from Pumping Well^2*Storage Coefficient)). Discharge is the volumetric flow rate of water that is transported through a given cross-sectional area. It includes any suspended solids, dissolved chemicals, or biologic material, Transmissivity is the rate at which groundwater flows horizontally through an aquifer or the degree to which a medium allows something, in particular electromagnetic radiation, to pass through it, Time Period is the duration over which groundwater observations, measurements, or modeling simulations are conducted. It can vary from short-term periods to long-term periods, Distance from Pumping Well is the horizontal distance between a specific point in an aquifer and the location of a pumping well. It influences the behavior of groundwater flow & Storage Coefficient is the volume of water released from storage per unit decline in hydraulic head in the aquifer, per unit area of the aquifer.

How to calculate Drawdown?

The Drawdown formula is defined as the change in groundwater level due to an applied stress, caused by events such as: Pumping from a well, pumping from a neighboring well. Time is derived on Semi-log sheet plotted against drawdown is calculated using Total Drawdown = (Discharge/(4*pi*Transmissivity))*ln((2.2*Transmissivity*Time Period)/(Distance from Pumping Well^2*Storage Coefficient)). To calculate Drawdown, you need Discharge (Q), Transmissivity (T), Time Period (t), Distance from Pumping Well (r) & Storage Coefficient (S). With our tool, you need to enter the respective value for Discharge, Transmissivity, Time Period, Distance from Pumping Well & Storage Coefficient and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

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