What Is the Confined Aquifer Theis Transient Well Drawdown Calculator?
The Theis non-equilibrium equation models transient hydraulic drawdown in confined aquifers subjected to constant continuous well pumping.
By integrating the exponential integral well function W(u), it accounts for aquifer storativity, transmissivity, radial distance, and pumping elapsed time.
This calculator computes dimensionless Theis parameter u, well function W(u), predicted piezometric drawdown s(r,t), and radius of cone influence.
How Does the Confined Aquifer Theis Transient Well Drawdown Calculator Work?
The calculation evaluates user-provided measurements using recognized domain equations, converts between measurement units, and adjusts for real-world efficiency factors.
Confined Aquifer Theis Transient Well Drawdown Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Theis non-steady radial flow formulation where W(u) is evaluated via exponential integral polynomial expansion.
How to Use the Confined Aquifer Theis Transient Well Drawdown Calculator
- Enter your primary measurements in the input fields above.
- Select your preferred units (e.g. metric or imperial) if applicable.
- Review or adjust operational assumptions such as field efficiency.
- Click Calculate to instantly generate the full results breakdown and visual chart.
- Use the Reset button at any time to clear the form and test a new scenario.
Step-by-Step Example Calculation
Municipal Well Drawdown (T = 450 m²/day, S = 2.5e-4, r = 60m)
Input Values:
Understanding Your Result
Your calculated result represents the realistic operational capacity or baseline output under the specified conditions. Comparing theoretical and effective outputs reveals the direct impact of turns, overlap, and practical downtime.
Factors That Affect the Result
Field terrain, operator experience, equipment maintenance, overlap margin, and weather conditions can significantly influence real-world output.
When Should You Use This Calculator?
Use this calculator whenever you need quick, verified estimates for job planning, budgeting, equipment sizing, or project timelines.
Assumptions & Limitations
- Valid for homogeneous, isotropic confined aquifers of infinite areal extent with 100% penetrating wells.
- For small values of u (u < 0.05), Cooper-Jacob logarithmic approximation can also be used.
Frequently Asked Questions
Calculation Accuracy & Reference Note
This calculator implements verified, deterministic mathematical equations based on published standards. Results should be treated as professional engineering estimates; always verify critical operations with local equipment manuals and site inspections.