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D5613-94 – Standard Test Method Technical Guide
ASTM D5613-94 (Reapproved 2014), titled Standard Test Method for Open-Channel Measurement of Time of Travel Using Dye Tracers, establishes a standardized procedure for measuring the travel time of water and dissolved solutes in open channels. This method, developed under the jurisdiction of ASTM Committee D19 on Water, aligns closely with techniques established by the U.S. Geological Survey and supports hydrologic studies focused on flow dynamics and pollutant transport.
📐 Scope and Regulatory Considerations
The scope of this standard covers the necessary dye tracers, measuring equipment, and field and laboratory procedures. It also provides methods for tracer study analysis and data presentation. The standard mandates specific unit usage: inch-pound units are standard except for chemical concentrations and liquid volumes for step dilutions, which must be reported in SI units. Section 1.4 explicitly requires the user to rigorously address the regulatory status of the tracer, including determining clearances for potable, industrial, irrigation, or fish and wildlife use, and securing all necessary agency approvals.
⚠️ Regulatory Clearance Requirement: Before conducting a tracer study, the user must determine whether the chemical has the required approvals from all involved agencies. Section 1.4 mandates thorough documentation of all contacts and notifications related to the tracer release.
⚙️ Tracer Equipment and Field Terminology
D5613-94 defines the specific equipment and sampling strategies required for a successful tracer study. The fluorometer is the primary analytical instrument for measuring dye luminescence under a given wavelength. Field samples can be collected using an automatic programmable sampler for sequential discrete samples at a single cross-sectional point, or via depth-integrated sampling to get a representative vertical profile of the moving water mixture.
| 🟦 📐 Key Terminology | 📖 Definition per D5613-94 |
|---|---|
| Centroid | The center of mass of the dye response curve. |
| Depth-Integrated Sample | A sample representative of the water mixture at a single vertical in a cross section. |
| Dispersion | The three-dimensional process of disseminating the dye within a river’s waters. |
| Flow Duration | The percentage of time during which a specific discharge is equalled or exceeded. |
| Fluorometer | An instrument that measures the luminescence of a fluorescent substance. |
📊 Data Analysis and Referenced Methods
Analysis of the collected data involves constructing the dye response curve and calculating the centroid to determine the mean time of travel. The standard references the Integration (Sudden Injection) Method outlined in ISO 555/2-1974 for liquid flow measurement. The concept of flow duration is used to correlate measured travel times with specific hydrological events and steady flow conditions.
| 📚 Referenced Standard | ⚡ Application in Tracer Study |
|---|---|
| ASTM D3858 | Open-Channel Flow Measurement of Water by Velocity-Area Method |
| ASTM D4411 | Guide for Sampling Fluvial Sediment in Motion |
| ISO 555/2-1974 | Liquid Flow Measurement in Open Channels — Dilution Methods (Integration Method) |
💡 Centroid Calculation Best Practice: The center of mass of the dye response curve is critical for accurate mean travel time determination. The standard references the calculation methodology by Parker and Hunt. Ensure the fluorometer is properly calibrated against known dye concentrations for reliable laboratory and field data.
❓ Frequently Asked Questions
🔍 What is the primary scope of ASTM D5613-94?
The standard provides a test method for measuring the time-of-travel of water and waterborne solutes in open channels using fluorescent dye tracers, similar to methods developed by the U.S. Geological Survey.
⚡ What units are required for chemical concentrations?
Inch-pound units are the standard for the method. However, chemical concentrations and liquid volumes used for step dilutions must be reported in SI units.
💡 What does the term “centroid” refer to in this method?
The centroid is defined as the center of mass of the dye response curve. It is the primary calculation used to determine the mean travel time of the solute plume passing a measurement station.
📌 What are the user’s responsibilities for safety?
Section 1.6 places the responsibility on the user to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use, with specific hazard statements located in Section 9.