What this tool does
Makes setup conflicts visible before a field team treats a numeric stabilization result as sufficient evidence.
When to use it
Use with surveyed well-construction data, measured initial and stabilized water levels, and limits copied from the approved site plan.
Inputs and supported units
Each labelled field explains the quantity it expects. Unit-system changes convert existing numeric entries once and keep calculations on a single SI internal basis. Supported shared units include L/min and GPM, metres and feet, kPa and psi, millimetres and inches, kW and hp, and °C and °F as relevant.
Calculation or decision method
Submerged head over intake = intake depth − stabilized depth to water
How to interpret the result
Read the primary result with the supporting breakdown and warning. A plausible number is not evidence that every input, operating case or design constraint has been included.
Worked example
For a 10–13 m screen, an intake at 11.5 m, initial water at 4 m and stabilized water at 4.08 m, drawdown is 0.08 m and 7.42 m of water remains over the intake.
Assumptions
Well construction, water levels, equipment dimensions, flow and field readings are site-specific measurements entered in consistent units. All comparison criteria are supplied by the user from the governing plan or authority.
Limitations
These tools calculate geometry, displacement and numeric variation only. They do not select a sampling method, prove sample representativeness, establish laboratory requirements or authorize collection or disposal.
Sources
- U.S. EPA — Groundwater Sampling Operating Procedure (EQASOP-GW4)
- U.S. EPA — Low-Flow (Minimal Drawdown) Ground-Water Sampling Procedures
- U.S. Geological Survey — Purge Analyzer Tool (PAT)