ISO 4365:2005

Overview

ISO 4365:2005 - "Liquid flow in open channels - Sediment in streams and canals - Determination of concentration, particle size distribution and relative density" specifies standardized laboratory and analytical methods for characterizing sediment in streams and canals. The standard defines procedures to determine suspended sediment concentration, particle‑size distribution (for suspended sediment, bed-load and bed material) and relative density of sediment. Detailed methods and laboratory procedures are provided in normative annexes (A–G).

Key Topics and Requirements

• Scope and definitions: Terms such as suspended load, bed-load, nominal/sieve/settlement diameters and relative density are defined in accordance with ISO vocabulary conventions.
• Sampling linkage: Suspended sediment sampling is referenced to ISO 4363; correct sampling is a prerequisite for analysis.
• Concentration methods:
  • Evaporation method (Annex A) - mass determination after drying (suitable for coarser particles).
  • Filtration methods (Annex B, C) - filter paper or glass‑fibre/Gooch/Coors/Alundum crucibles with vacuum filtration; annexes note advantages/limitations (e.g., potential loss of very fine particles).
  • Hydrometer method - referenced for some sizing/concentration tasks (noted as temperature‑sensitive).
• Particle‑size analysis:
  • Classification by size ranges: coarse (>0.25 mm), medium (0.062–0.25 mm), fine (<0.062 mm).
  • Annex D: particle‑size distribution of suspended sediment.
  • Annex E: particle‑size distribution for bed‑load and bed material.
  • Methods include sieving for coarser fractions and sedimentation/hydrometer techniques for fines.
• Relative density: Determination procedures are given (Annex F) to support settling velocity and transport calculations.
• Data treatment: Expression of concentration (mass/volume or mass/mass), particle‑size distribution characteristics (Annex G), and SI units are required.

Applications and Practical Value

ISO 4365:2005 is used to produce consistent, comparable sediment characterization data for:

• River and canal engineering (sediment transport analysis, channel design)
• Reservoir and dredging planning (sediment yield and accumulation estimates)
• Erosion and catchment management (sediment budgets)
• Environmental monitoring and impact assessments (suspended sediment loads)
• Calibration and validation of sediment transport models

Accurate concentration, size distribution and relative density data enable reliable sediment load computations, settling velocity estimates and informed decisions on maintenance, mitigation and design.

Who Uses This Standard

• Hydrologists and hydrometric teams
• Civil and environmental engineers
• Sedimentologists and geomorphologists
• Water resource and reservoir managers
• Laboratory technicians performing sediment analysis

Related Standards

• ISO 4363 - Measurement of liquid flow in open channels - Methods for measurement of characteristics of suspended sediment
• ISO 4364 - Measurement of liquid flow in open channels - Bed material sampling
• ISO 772 - Hydrometric determinations - Vocabulary and symbols

Keywords: ISO 4365:2005, sediment concentration, particle-size distribution, relative density, suspended sediment, bed-load, filtration method, evaporation method, hydrometry, open channels.