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Wisconsin River Report May 8, 2008

Wisconsin Valley Improvement Company 2301 North Third Street Wausau, WI  54403 For more information contact Sam Morgan Phone: 715.848.2976, ex 301 Email: morgan@wvic.com

 

Wisconsin River Reservoir Storage Highest in Four Years

 

Above normal snowfall during the past winter and timely rains in April and early May created enough runoff this spring to fill the Wisconsin River Reservoir System to its highest level since June 2004 according to Wisconsin Valley Improvement Company (WVIC) of Wausau. River flows along the Wisconsin River this spring were the highest they have been since the spring of 2003, but no flooding problems were reported.

Storage in WVIC’s system of 21 reservoirs used for flood control and low flow augmentation on the Wisconsin River now stands at 84% of capacity and is still rising slowly. The last time the reservoir system was this full was in June 2004 when storage hit 92%. Normal storage in early May is 77% of capacity. Three of WVIC’s five large reservoirs have reached the full mark. Eau Pleine Reservoir near Mosinee filled on April 14, Spirit Reservoir south of Tomahawk filled on April 16, and Rice Reservoir (Lake Nokomis) north of Tomahawk reached the full mark earlier this week. Rainbow Reservoir near Minocqua is still 3.5 feet below full, but the water level there is rising steadily and should be close to full in about 10 days. The only large reservoir that is not on track to fill completely is the large Willow Reservoir near Hazelhurst, which is still 3.8 feet below full and rising slowly. Without more significant rain in the northwoods this spring, Willow will stop refilling at about 3 feet from full. Thirteen of WVIC’s sixteen smaller natural lake reservoirs have also reached the full mark. The other three, Squirrel Lake west of Minocqua, the Minocqua Chain, and Twin Lakes near Phelps are all within 4 inches of the summer target levels and still rising.

River flows along the Wisconsin River peaked during the third week of April as snowmelt combined with about one inch of rain to produce the highest flows in five years. Peak flows reached 13,400 cubic feet per second (cfs) at Merrill, 28,200 cfs at Rothschild, 40,800 cfs at Wisconsin Rapids, and 42,700 cfs at Muscoda. Flood control provided by WVIC’s reservoir system and three of the large hydroelectric dams along the river reduced flood peaks by 20-30% and flows at all locations stayed below damaging levels.

Rainfall during April averaged 3.86 inches, or 55% above normal, in the northern Wisconsin River basin upstream from Tomahawk and 5.90 inches, or more than twice normal, in the central basin between Tomahawk and Wisconsin Rapids. During the first week of May rainfall averaged 1.59 inches in the northern basin and 0.63 inches in the central basin. Normal rainfall for a week in May is 0.80 inch. Total precipitation so far in 2008 is running 16% above normal in the north and 26% above normal in the central basin.

 

 

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