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Drought Conditions Deplete Reservoir Storage

 

A continued lack of significant rainfall and temperatures that averaged as much as eleven degrees above normal last week caused reservoir storage to drop 4% to 66% of capacity according to Wisconsin Valley Improvement Company (WVIC) of Wausau. Water levels in WVIC’s five large reservoirs that are used to control the flow of the Wisconsin River are now as much as six feet below full.

Rainfall averaged 0.66 inch in the upper basin north of Tomahawk and only 0.25 inch in the central basin between Tomahawk and Wisconsin Rapids. Normal rain for a week in August is 0.90 inch. Total rainfall for the summer season is now almost 40 % below normal.

Temperatures soared to the highest readings of the summer last week with daily highs hitting 86 degrees in the north, 90 degrees in the central valley, and 97 degrees in the southern valley. The weekly average temperature at the Willow Reservoir near Hazelhurst of 74 degrees was eleven degrees above the August normal. The weekly average of 75 degrees at Wausau was 7 degrees above normal, while the average of 78 degrees at Prairie du Chien was 6 degrees above normal.

The hot, dry conditions caused river flows to drop to the lowest levels the summer. The flow of the Wisconsin River at Merrill averaged 1,330 cubic feet per second (cfs), 28% below normal. The flow at Wisconsin Rapids of 2,148 cfs was 23% below normal and on the lower river at Muscoda the flow of 3,005 cfs was 45% below normal. Water released from the Reservoir System provided 52% of the river flow at Merrill and 49% of the river flow at Wisconsin Rapids.

The water temperature in the Wisconsin River averaged 78 degrees, 6 degrees above the seasonal normal.

 

Reservoir Water Levels			River Flow			Precipitation
Location	Feet Below Max	Weekly Change (Ft.)	Location	Weekly Average (cfs)	Monthly Normal (cfs)	Location	This Week (In.)	Annual Total (In.)	+/- Annual Normal
Rainbow	6.3	-0.8	Eagle River	N/A	404	Upper Basin	0.66	18.29	-2.26
Willow	5.1	-0.9	Tomahawk	1,417		Central Basin	0.25	17.00	-3.55
Rice	3.4	-0.5	Merrill	1,330	1,848	Temperature
Spirit	4.3	-0.7	Rothschild	1,703		Location	Ave.	Normal	+/-
Eau Pleine	5.7	-0.8	St. Point	2,167		Willow Reservoir	74	63	+11
Reservoir Storage			Wis. Rapids	2,148	2,780	Wausau	75	68	+7
Northern	65%	-4%	Petenwell	1,993	2,900	Prairie du Chien	78	72	+6
Overall	66%	-4%	Muscoda	3,005	5,541

 

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