ASTM D 4558 : 1985 : R1995

1.1 Drift nets are useful for collecting macroinvertebrates that actively or passively enter the water column or that are dislodged from the substrate; naturally or by stress. They are particularly well-suited for synoptic surveys because they are light weight and easily transported.

1.2 Thousands of organisms, including larvae of stoneflies, mayflies, caddisflies, and midges and other Diptera, may be collected in a sampling period of only a few hours.

1.3 The drift net efficiently collects organisms originating from all types of substrates and a wide spectrum of microhabitats in lotic (flowing) waters.

1.4 The device is restricted to flowing rivers or streams with a current velocity of more than 0.05 m/s.

1.5 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems 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 limitations prior to use.