ASTM D3858-95 (2014) PDF

Full title and description

Standard Test Method for Open-Channel Flow Measurement of Water by Velocity-Area Method — a field test method that specifies procedures for measuring volumetric flow (discharge) in natural and constructed open channels by determining velocity and cross-sectional area and computing discharge from their product.

Abstract

This test method defines the velocity‑area approach: measure point velocities across a channel cross section (commonly using current meters or equivalent velocity sensors), determine partial areas for each sampling subsection, compute mean velocities for those subsections, and sum the products of mean velocity and area to obtain total discharge. It is intended for streamflow and open‑channel discharge determinations and for calibration of structures (flumes, weirs) where direct area–velocity measurements are required.

General information

• Status: Withdrawn (withdrawal noted January 2023).
• Publication date: Approved Jan 1, 2014; published January 2014 (reapproval of D3858‑95).
• Publisher: ASTM International.
• ICS / categories: 17.120.20 — Flow in open channels.
• Edition / version: Designation D3858‑95 (reapproved 2014).
• Number of pages: 9 pages.

Scope

The standard covers measurement of the volumetric flowrate of water in open channels by determining velocity and cross‑sectional area and computing discharge therefrom. It applies to field measurements in rivers, streams and constructed channels and to discharge determinations made from bridges, cableways, boats, wading, or holes cut in ice; it is intended for use with point‑velocity instruments such as current meters and other velocity probes.

Key topics and requirements

• Principle of velocity‑area discharge computation (Q = Σ(av) for partial areas and mean velocities).
• Selection and use of velocity measurement devices (current meters, acoustic/propeller probes) and recommended procedures for point sampling across a cross section.
• Division of channel cross section into partial areas and procedures for estimating mean velocities for each subsection.
• Data reduction and computation of discharge, including recommended presentation of results and basic precision considerations.
• Field practice notes (measurement from bridges, boats or wading; methods for ice-covered channels) and safety considerations for field crews.

Typical use and users

Hydrologists, river and water‑resources engineers, government agencies (for example, USGS, Bureau of Reclamation, U.S. Army Corps of Engineers), environmental consultants, and researchers use this method for routine streamflow measurements, site calibration of gauging structures, and hydrologic studies where direct discharge measurements are required.

Related standards

Standards and documents commonly referenced with D3858 include ASTM D4409 (velocity measurements with rotating‑element current meters), ASTM D5089 (other velocity‑measurement techniques), and international guidance such as ISO documents on open‑channel flow measurement; users are advised to consult related D19 committee publications for instrumentation and precision practices.

Keywords

open‑channel flow, discharge measurement, velocity‑area method, current meter, streamflow, cross‑sectional area, hydrometry.

FAQ

Q: What is this standard?

A: ASTM D3858‑95(2014) is a test method that prescribes the velocity‑area procedure for measuring volumetric flow (discharge) in open channels by combining measured velocities and cross‑sectional areas.

Q: What does it cover?

A: It covers field procedures for measuring point velocities across a channel, dividing the cross section into partial areas, computing mean subsection velocities, and summing products of velocity and area to obtain total discharge; it includes guidance on measurement situations (bridges, boats, wading, ice) and general practice notes.

Q: Who typically uses it?

A: Hydrologists, water‑resources agencies, engineers, and researchers performing streamflow measurements and calibrating open‑channel structures commonly use this method.

Q: Is it current or superseded?

A: This document was reapproved/published in 2014 but was withdrawn in January 2023 (ASTM lists it as withdrawn with no direct replacement noted). Users should verify current practice and check for newer ASTM or national guidance before relying on withdrawn procedures.

Q: Is it part of a series?

A: It falls under ASTM Committee D19 (Water) and Subcommittee D19.07 (Sediments, Geomorphology, and Open‑Channel Flow) and is commonly used together with other D19 open‑channel and velocity measurement standards.

Q: What are the key keywords?

A: discharge measurement; open‑channel flow; velocity‑area; current meter; streamflow; cross‑sectional area.