ISO 21413:2005 PDF

Overview

ISO 21413:2005 - "Manual methods for the measurement of a groundwater level in a well" - specifies standardized procedures and minimum accuracy requirements for manual groundwater level measurement in wells. The standard covers three manual methods - graduated steel tape, electric tape, and air-line - plus procedures for measuring flowing (overflowing) wells and for establishing a permanent measuring point. ISO 21413:2005 explicitly excludes automated electrical or mechanical logging systems.

Key topics and requirements

• Measurement methods: Detailed procedures for the graduated steel tape (wetted-tape), electric tape (contact-sensor), and air-line (pressurized tube) methods.
• Flowing well procedures: Techniques and accuracy considerations for measuring water levels in wells that discharge at the ground surface.
• Permanent measuring point (MP): Steps to establish and document a stable reference point on the well casing and relate it to land-surface datum.
• Accuracy requirements:
  • Independent steel tape measurements should agree within ±1.0 cm for depths