What Is the Hantush-Jacob Leaky Confined Aquifer Drawdown Calculator?
The Hantush-Jacob (1955) solution models groundwater flow to a fully penetrating well in a leaky confined aquifer bounded by an aquitard with vertical recharge.
Unlike the non-leaky Theis equation where drawdown grows indefinitely with log time, leakage from the aquitard stabilizes the cone of depression into a steady-state equilibrium.
This calculator computes the leakage factor B, dimension parameter u, leaky well function W(u, r/B), and drawdown s(r,t).
How Does the Hantush-Jacob Leaky Confined Aquifer Drawdown Calculator Work?
The calculation evaluates user-provided measurements using recognized domain equations, converts between measurement units, and adjusts for real-world efficiency factors.
Hantush-Jacob Leaky Confined Aquifer Drawdown Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Evaluates Hantush-Jacob well function W(u, r/B) integrating exponential Bessel decay to calculate drawdown s as a function of radial distance and leakage factor B.
How to Use the Hantush-Jacob Leaky Confined Aquifer 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
Industrial Wellfield in Leaky Alluvial Aquifer
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
- Assumes no storage change within the aquitard itself (incompressible aquitard assumption). For thick clays with aquitard storage, Hantush (1960) modified theory applies.
- As r/B approaches zero, the Hantush-Jacob solution simplifies to the classic Theis non-leaky confined equation.
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.