Submitted to: Water Resources Bulletin
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 26, 1995
Publication Date: N/A
Interpretive Summary: Freezing temperatures at the North Appalachian Experimental Watershed at Coshocton, Ohio cause ice to form on weirs (devices used to measure flows in stream channels) and in weir pools during winter operation of permanent runoff gaging stations. The ice conditions cause erroneous gage heights to be measured. A simple, inexpensive method using a pump for solving this problem is evaluated. The pump draws warmer water from the bottom of the weir pool and pumps it to the surface to minimize formation of ice. The pump system is shown to improve runoff records during the winter. Persons operating runoff gaging stations including consulting engineers and Federal and State agencies will benefit from this study.
Technical Abstract: Freezing winter temperatures can cause icing of outdoor weirs used to measure surface runoff. Ice typically forms in the notch and on the crests of short-crested V-notch weirs, causing erroneous gage heights to be measured. A method for minimizing the effects of ice formation on weirs and weir pools using a pump is presented and evaluated. Warmer water from the bottom of the weir pool is pumped to the surface, minimizing the opportunity for the water surface to freeze. The pump system is shown to work except under extremely cold conditions. The pump system has no practical effect on measured gage height. Suggestions and guidelines for use of the pump system under temperature conditions different from those of this study are given.