ISO 14139:2000 PDF

Overview

ISO 14139:2000 - Hydrometric determinations - Flow measurements in open channels using structures - Compound gauging structures - specifies accepted methods for measuring flow in rivers and artificial channels using any combination of standard weirs and/or flumes arranged in a compound (parallel) structure. The standard covers operational ranges, measurement procedures, installation and maintenance guidance, and computation methods. Key normative annexes describe velocity distribution (Annex A), non‑modular (drowned) flow and its computation (Annex B), and worked calculation methods and examples (Annex C).

Key topics and technical requirements

• Definition: a compound gauging structure comprises two or more individual weirs/flumes operated in parallel and separated by divide piers.
• Modular vs drowned flow:
  • Modular flow - discharge depends only on upstream water level; a single upstream head measurement suffices.
  • Drowned (non‑modular) flow - discharge depends on upstream and downstream water levels; two independent head measurements are required (upstream + crest/ throat/tailwater as specified).
• Measurement of head: guidance on stilling wells, zero setting, and placement of head measurement sections to ensure accurate gauging.
• Installation and site selection: requirements for approach channel geometry, channel straightness, bank stability, foundation impermeability, and avoidance of upstream/downstream disturbances that could cause drowning.
• Computation and uncertainty: procedures for calculating section and total discharge, treatment of errors and uncertainty propagation, and presentation of results.
• Scope exclusions: compound structures without divide piers require in‑situ or model calibration and are not covered by ISO 14139.
• Normative guidance: selection of appropriate weirs/flumes is referenced to ISO 8368.

Practical applications and who uses it

ISO 14139 is intended for professionals involved in hydrometry and open‑channel flow measurement, including:

• Hydrologists and water resources engineers monitoring river discharge and streamflow.
• Gauging station designers and field technicians installing and maintaining weirs/flumes.
• Environmental agencies, irrigation authorities, and consultants performing water accounting, flood monitoring, and hydraulic assessments. Practical benefits include improved accuracy at low stages (compound weirs), standardized head‑measurement practice, consistent computation of flows in both modular and drowned regimes, and clear guidance for minimizing measurement uncertainty.

Related standards

• ISO 8368 - Guidelines for selection of structure (referenced for choosing weirs/flumes)
• ISO 772 - Hydrometric vocabulary and symbols
• ISO 1438‑1, ISO 3846, ISO 4359, ISO 4360, ISO 4362, ISO 4374, ISO 4377, ISO 8333, ISO 9826, ISO 9827 - standards for individual weir and flume types referenced by ISO 14139

Keywords: ISO 14139, compound gauging structures, flow measurement, open channels, weirs, flumes, hydrometry, drowned flow, modular flow, discharge measurement.