ASTM D6764

Significance and Use

5.1 This guide describes stabilization criteria for recording field measurements of Temperature, DO, SC, and pH.

5.2 This guide describes the procedures used to calibrate and check meters to be used in the field to records these measurements and the procedures to be use in the field to obtain these data.

5.3 This guide describes quality assurance procedures to be followed when obtaining cross-sectional means of temperature, dissolved oxygen, specific electrical conductance, and pH of water flowing in open channels.

TABLE 1 Stabilization Criteria for Recording Field Measurements (1)

Note 1—[±, plus or minus value shown; °C, degrees Celsius; ≤ less than or equal to values shown; μS/cm microsiemens at 25°C, >, greater than value shown; unit, standard pH unit; mg/L milligram per liter].

Standard Direct Field Measurement	Stabilization Criteria for Measurements (Variability Should Be Within the Value Shown)
Temperature: Electronic Temperature Sensor Liquid-in-glass thermometer	±0.2°C ±0.5°C
Specific Electrical Conductance: when ≤ 100 mS/cm when > 100 mS/cm	±5 % ±5 %
pH: Meter displays to 0.01	±0.1 unit
Dissolved oxygen: Amperometric method	±0.3 mg/L

5.4 Field measurement must accurately represent the water flowing in the open channel being measured. Methods need to be used that will result in an accurate representation of the mean of the parameter of interest. Procedures must be used that will take into consideration the variation in the parameter across the sections and with depth.

5.5 Temperature and DO must be measured directly in the water in the open channel. SC and pH are often measured in situ, but also may be measured in a subsample of a composite sample collected using discharge-weighted methods.

1. Scope

1.1 This guide describes procedures to collect cross-sectional means of temperature, dissolved oxygen, specific electrical conductance, and pH of water flowing in open channels.

1.2 This guide provides guidelines for preparation and calibration of the equipment to collect cross-sectional means of temperature, dissolved oxygen, specific electrical conductance, and pH of water flowing in open channels.

1.3 This guide describes what equipment should be used to collect cross-sectional means of temperature, dissolved oxygen, specific electrical conductance, and pH of water flowing in open channels.

1.4 This guide covers the cross-sectional means of temperature, dissolved oxygen, specific electrical conductance, and pH of fresh water flowing in open channels.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory requirements prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.