EQUIPMENT & SUPPLIES: DH-75 Suspended-Sediment Sampler

                                           January 17, 1977


Subject: EQUIPMENT & SUPPLIES: DH-75 Suspended-Sediment Sampler

The Federal Interagency Sedimentation Project recently has 
introduced the DH-75 series of suspended-sediment samplers. The 
DH-75 sampler was first described in an article by Steven H. 
Hindall in the April-June 1974 WRD Bulletin as the "Hindall 
Sampler."  The sampler was designed specifically for sampling 
under ice using the standard pint sample bottle.

Hindall's original design was modified by the Sedimentation 
Project to hold a plastic 500-ml bottle (DH-75P). They then 
developed two other models that hold 1000 ml (DH-75Q) and 2000 ml 
(DH-75H) containers. These samplers were listed for sale in their 
1977 Fiscal Year price list. All models are intended for use on a
wading rod for sampling under ice.

The purpose of this memo is to inform you that all three of these
models are acceptable for use within WRD for sampling under ice.
Also, the 500 ml and the 1000 ml models may be used for the 
collection of samples in open waters by wading or from a boat when 
a wading rod can be utilized. The DH-75H (2000 ml ,model) is not 
recommended for the collection of water-sediment samples in open 
waters except for low velocity flow where no silt-or sand-size 
particles are in suspension. The reason for this is because the 
unsampled zone is about 50 percent greater for the DH-75H than for 
the DH-48; therefore, the DH-75H data are not comparable to DH-48 
data for the silt plus sand fractions.

No attempt should be made to suspend any of the DH-75 samplers 
from a reel and cable. The Sedimentation Project currently is 
attempting to develop a satisfactory large-volume sampler for 
general water-quality and suspended-sediment sampling under 
extreme low temperature conditions. As soon as such a sampler is 
available the field offices will be notified.

                             R. J. Pickering
                             Chief, Quality of Water Branch

WRD Distribution: A, FO, PO