Sampler, BMH-60

HIF/FISP Part # 4103009

The US BMH-60 is a hand-line bed-material sampler. It is used to collect samples from the bed of a stream, lake, or a reservoir. Penetration into the bed material is approximately 1.7 in. The sampler can be suspended from a flexible line and lowered and raised by hand. The weight of the sampler limits its use to tranquil streams and moderate or slightly compacted sand and pebble bed materials.

The US BMH-60 is 22 in long and weighs 32 lbs. The body of the sampler is made of aluminum. Ballast makes the sampler nose heavy by about four pounds to assist the sampling bucket mechanism in penetrating the bed material of the stream. The sampling bucket accommodates approximately 11 in3 (175 cm3) of material and is spring loaded by cross-curved, constant-torque, motor-type springs. Tension on the hand suspension line or use of a specially made safety yoke allows the bucket to be cocked in the open position by means of a wrench. Once the bucket is fully retracted within the body shell of the sampler, it is ready to take a sample. As long as the safety yoke is in place, the bucket mechanism cannot be released. For sampling, the safety yoke is removed and the sampler lowered by the hand line until the sampler rests on the bottom of the stream. Once the tension on the suspension line is reduced to a specified amount, the spring-loaded cocking device will release the bucket mechanism. The rapidly closing bucket penetrates the streambed and completely encloses a sample of the bed material. Gaskets prevent loss or contamination of the trapped sample. Once the sampler is raised to the surface, the bed material sample can be transferred to a container. HIF Repairable.

Where and how the sampler is deployed in the field is as important as the fundamental design of the sampler. Additional information about how to properly use this sampler can be found in the following references:

Edwards, T.K., and Glysson, G.D., 1999, Field Methods for Measurement of Fluvial Sediment: U.S. Geological Survey Techniques of Water Resources Investigations, book 3 chapter C2, 89 p.