This code provides guidelines for conducting field geohydrological investigations to assess aquifer characteristics like transmissivity and storativity. It details procedures for various tests including pumping tests, recuperation tests, tracer studies, and geophysical methods to understand groundwater availability and movement.
Lays down field methods for geohydrological investigations, including drilling, pumping tests, and water level measurements.
Key Formulas
Theis's Non-Equilibrium Formula: s = (Q / 4πT) * W(u) — For determining transmissivity (T) and storativity (S) from drawdown (s) over time.
Thiem's Equilibrium Formula: T = [Q / (2π(s1-s2))] * ln(r2/r1) — For determining transmissivity (T) under steady-state conditions using drawdown at two observation wells.
Slichter's Formula: K = (πr²/A(t2-t1)) * ln(s1/s2) — For determining hydraulic conductivity (K) from a recuperation test.
Practical Notes
Ensure pumped water is discharged far enough away to prevent recirculation into the aquifer, which can skew test results.
Achieving true steady-state conditions for equilibrium tests can be time-consuming, especially in low-permeability formations; non-equilibrium methods are often more practical.
Geophysical survey results are indirect and should always be correlated with direct data from boreholes or pumping tests for accurate interpretation.