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Summer of 2003 Driest in 27 Years

 

The summer of 2003 went in the books at the driest summer in 27 years and the second driest summer in the last 66 years according to Wisconsin Valley Improvement Company (WVIC) of Wausau. Total rainfall for the three-month period June through August averaged only 7.5 inches over the central and northern portions of the Wisconsin River Basin. The last time summer rainfall was this low was in 1976, and the next driest summer dates all the way back to the dust bowl year of 1937.

Normal rainfall for the three-month summer season is 11.8 inches, making rainfall for the summer of 2003 almost 40% below normal. The central portion of the Wisconsin River Basin was especially dry with some areas reporting rainfall totals that were less than half of normal.

The extended dry weather has caused river flows to plunge to extremely low levels. The regulated flow of the Wisconsin River at Merrill dipped to 1,292 cubic feet per second (cfs) last week, almost 30% below normal. Water released from WVIC’s northern reservoir system provided 57% of the flow at Merrill. At Wisconsin Rapids the regulated flow of 1,830 cfs was 35% below normal with reservoir water providing 65% of the flow.

Flows on some tributary rivers that supply the Wisconsin River have dropped to almost nothing. The flow of the Spirit River near Tomahawk is now only 6 cfs and the flow of the Big Eau Pleine River near Mosinee is only 3 cfs. Both flows are more than 90% below normal.

Storage in WVIC’s reservoir system that is used to regulate the flow of the Wisconsin River has fallen to 57% of capacity and continues to drop at the rate of 4% per week. Water levels in the five large reservoirs range from four feet to almost eight feet below maximum, the lowest summer levels in five years. With no significant rainfall in the forecast for the next week, both reservoir water levels and river flows are expected to continue falling in early September.

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	7.7	-0.9	Eagle River	N/A	492	Upper Basin	0.00	18.85	-2.50
Willow	6.9	-0.9	Tomahawk	1,358		Central Basin	0.00	16.94	-5.09
Rice	4.0	-0.4	Merrill	1,292	1,806	Temperature
Spirit	5.5	-0.5	Rothschild	1,468		Location	Ave.	Normal	+/-
Eau Pleine	7.6	-0.9	St. Point	1,821		Willow Reservoir	60	59	+1
Reservoir Storage			Wis. Rapids	1,584	3,071	Wausau	62	64	-2
Northern	58%	-4%	Petenwell	1,474	4,000	Prairie du Chien	68	68	0
Overall	57%	-4%	Muscoda	3,058	7,548

 

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