In Reply Refer To:                               September 19, 1988
WGS-Mail Stop 415


Subject:  EQUIPMENT AND SUPPLIES--Winter Equipment

The Water Resources Division and Water Survey of Canada (WSC) are
working together to improve and standardize discharge measurements
under ice cover.  Slight differences in technique and equipment
have resulted in differences in measured discharge and ratings at
several international gaging stations.  This problem was jointly
investigated in the field (Pelletier, Patrice M., 1988, "An
Investigation of the Measurement of Streamflow Under Winter
Conditions:  International Hydrometric Gauging Station on the Red
River at Emerson, Manitoba, Canada," Environment Canada, Report
No. IWD-WNR(W)-WRB-HI-88-1).  Meetings of personnel from both
agencies at Edmonton, Canada, in November 1987 and at the
Hydrologic Instrumentation Facility (HIF) in May 1988 resulted in
the following recommendations based on field experience and other
considerations.  The recommendations are intended as general
guidelines, recognizing that certain locations or conditions may
require special adaptations of equipment.  These recommendations,
however, supersede previous guidance on this subject.

Current Meters

The preferred ice-metering equipment is a type AA current meter
built with a WSC winter-style meter yoke with polymer bucket
wheel.  It should be used with a WSC ice foot on either the
U.S. Geological Survey sectional 0.5-inch or 1.0-inch ice rod.
The WSC has indicated that they will be using their winter rod in

Ice Weight

A standard 30-pound Columbus-type sounding weight with a collapsi-
ble hanger assembly, capable of passing through an 8-inch hole,
has been retrofitted to accommodate the meter described above.
This configuration has been tested at the Office of Surface Water
(OSW) hydraulics laboratory at the John C. Stennis Space Center,
Mississippi, and operates satisfactorily up to velocities of 5
feet per second.  Test and evaluation are planned using a 50-pound
Columbus weight.

This meter and weight assembly will be procured and modified by
the HIF and individually calibrated by the OSW hydraulics labora-
tory.  The assembly will be available for the 1988-89 winter
season.  Advance orders and inquiries should be directed to the
Chief, Field Service and Supply Section, HIF, FTS 494-2108
(commercial 601/688-2108).

                                       Ernest F. Hubbard, Jr.
                                       Acting Chief, Office of Surface

WRD Distribution:  A, B, S, FO, PO

This memorandum supersedes HIF Memorandum No. 82.06 and Surface
Water Branch Technical Memorandum No. 84.05.

Copy to:  Mr. P. I. Campbell
          Chief, Water Survey of Canada
          Environment Canada
          Ottawa, Ontario  K1A OE7