ASTM D5541-24
Standard Practice for Developing a Stage-Discharge Relation for Open Channel Flow

Standard No.

ASTM D5541-24

Release Date

2024

Published By

American Society for Testing and Materials (ASTM)

Latest

ASTM D5541-24

Introduction

Analysis of the core content of the standard

ASTM D5541-24 specifies a systematic method for establishing the relationship curve between water level (GH) and flow (Q) in open channels, which mainly includes the following technical elements:

Control type	Characteristics	Applicable flow range	Typical examples
Section control	Specific cross-section determines the water level-flow relationship	Low flow	Rock sill, small weir
River channel control	Relationship determined by comprehensive characteristics of the downstream river section	High flow	Long river sections with gentle slopes
Compound control	Dual control exists in the transition zone	Medium flow	Transition zone from section control to river channel control

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Key technical implementation points

1. Curve establishment steps

The standard recommends using the current meter method (D3858) or the indirect flow measurement method (D5129, etc.) to obtain benchmark data:

1. Plot water level-flow scatter plots on double-logarithmic coordinate paper
2. Identify the turning point of the curve slope caused by the change of control type
3. Use D5388 standard's retreat method to establish the theoretical curve
4. Adjust the theoretical curve shape according to the measured data

2. Interference Factor Treatment

The standard specifically points out that the following interference factors need to be paid attention to:

• Riverbed scour/siltation: the curve needs to be recalibrated
• Aquatic plant growth: water level correction is required
• Ice cover impact: a separate calibration is required in winter
• Hysteresis effect: different curves are required for rising and falling water

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Standard Evolution and Industry Application

This standard is derived from the USGS technical report (Kennedy 1984, Rantz 1982) and is mainly used in:

USGS Application Case

In the long-term monitoring of the Colorado River Basin, the average error of the curve established using the D5541 standard is <5%, of which:

• The error in the low-flow section (section control) is 2.3%
• The error in the high-flow section (river channel control) is 4.7%

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Implementation Recommendations

1. Quality Control Measures

• New stations should be measured monthly until the full water level is covered
• Recalibration is required after major floods
• Measurement quality grading management (excellent/good/fair/poor)

2. Special working condition handling

It is recommended to refer to the ISO 1100/2 standard when encountering the following situations:

• Extremely gentle slope river channel (slope <0.0001)
• Artificially regulated river channels
• Tidal river sections

ASTM D5541-24 Referenced Document

• ASTM D1129 Standard Terminology Relating to Water
• ASTM D3858 Standard Test Method for Open-Channel Flow Measurement of Water by Velocity-Area Method
• ASTM D5129 Standard Test Method for Open Channel Flow Measurement of Water Indirectly by Using Width Contractions
• ASTM D5130 Standard Test Method for Open-Channel Flow Measurement of Water Indirectly by Slope-Area Method
• ASTM D5243 Standard Test Method for Open-Channel Flow Measurement of Water Indirectly at Culverts
• ASTM D5388 Standard Test Method for Indirect Measurements of Discharge by Step-Backwater Method
• ASTM D5413 Standard Test Methods for Measurement of Water Levels in Open-Water Bodies
• ISO 1100-2 Hydrometry - Measurement of liquid flow in open channels - Part 2: Determination of the stage-discharge relationship

ASTM D5541-24 history

• 2024 ASTM D5541-24 Standard Practice for Developing a Stage-Discharge Relation for Open Channel Flow
• 1994 ASTM D5541-94(2014) Standard Practice for Developing a Stage-Discharge Relation for Open Channel Flow
• 1994 ASTM D5541-94(2008) Standard Practice for Developing a Stage-Discharge Relation for Open Channel Flow
• 1994 ASTM D5541-94(2003) Standard Practice for Developing a Stage-Discharge Relation for Open Channel Flow
• 1994 ASTM D5541-94(1998) Standard Practice for Developing a Stage-Discharge Relation for Open Channel Flow

Standard and Specification