January 16, 2003

Half of the flow in the Wisconsin River at Merrill January 12 was water released from reservoirs that had been stored during above normal autumn precipitation according to Wisconsin Valley Improvement Company (WVIC), Wausau. The nature of Wisconsin River basin hydrology since, WVIC noted, has been dry. When the supply of water flows, 21 headwater reservoirs fill with runoff, and when the supply ebbs, the purpose of WVIC's longstanding water conservation and streamflow regulation system stands out for its hydrologic value.

In contrast to the Wisconsin, a major upper basin tributary, the U.S. Coast Guard Jan. 16 closed sections of the Mississippi River to navigation due to flow running at a 13-year low. The lack of antecedent moisture combined with ice-making cold shrunk the supply of water available to the continent's largest drainage.

WVIC is a private company owned by paper mill companies and electric utilities that operate hydroelectric dams on the Wisconsin River. The company is licensed by the Federal Energy Regulatory Commission because flow regulation contributes to interstate commerce. Since it began operation in 1907, WVIC's purpose has remained the regulation of as uniform a flow in the Wisconsin River as practicable. Out if a corporate and regulatory stewardship, the Wisconsin flowed at a normal rate.

The current cold dry spell in Wisconsin results from a maturing El Nino, a suppressed southern jet, a ridge building in the west and a trough deepening in the east. There hasn't been enough moisture in the atmosphere to ring more than tenths or hundredths of inches of water from it in the form of light, fluffy snow, and then only at scattered locations.

Near, yet far, a snowstorm was blown south of Wisconsin Jan. 16 by the high altitude steering wind. The ridge-trough set up was forecast to pump the deepest cold of the winter into the valley Jan. 20-24.

Natural flow in the Wisconsin River at Merrill, flow occurring without reservoir operation, was 1,200 cubic feet per second (cfs) January 12, a decrease of 44 cfs. Natural flow was 89 percent of or 145 cfs below the 1,345 cfs January normal.

Reservoir release above Merrill amounted to 601 million cubic feet of water or 993 cfs. Release augmented natural flow by 45 percent to achieve a regulated flow of 2,193 cfs, 193 cfs above the 2,000 cfs Merrill flow goal. The target flow at Wisconsin Rapids is 2,900 cfs.

Weekly average regulated flow in the Wisconsin River Jan. 10-16 was normal. Cold causes decreases in flow as ground, wetland and bank storage supplies are shrunk by freezing. Deep cold forecast for Jan. 20-24 would place a further flow-reducing squeeze on the 430-mile long stream.

Reservoir storage Jan. 12 was 51 percent of maximum. Using mid-March as a general benchmark for breakup on the Wisconsin River, flow augmentation from reservoirs would run another eight weeks.

Weekly average temperatures in the upper and central Wisconsin Valley were below normal Jan. 10-16. The coldest lows were minus 5 degrees at Willow reservoir in western Oneida County Jan. 14 and 15, and minus 3 degrees at Wausau Jan. 14.

National Weather Service forecasters predict bitterly cold Arctic air will surge into the region Jan. 20-24. Before the outbreak, two systems may produce snow Jan. 17-18 and Jan. 19-20. If snow covers the ground, the forecasters predict temperatures will be much colder than if the ground remains snow free.

-End of Report-