The Eau Galle River has its origins in St.Croix County and flows 51 miles to its confluence with the Chippewa River in Pepin County. Early settlers found the Eau Galle River to be an exceptional Trout Stream supporting large native Brook Trout. As with many area streams, changing land use degraded water quality and habitat leaving the native Brook Trout only in the far reaches of the river's headwater streams. The introduction of the Brown Trout, which tolerates warmer water than the Brook, allowed for an excellent fishery. In 1966, an earthen flood control dam was constructed to protect the village of Spring Valley.

The dam forms a 150-acre impoundment, which is located 50 miles east of the Twin Cities and 40 miles southwest of Eau Claire. The river is a relatively large trout stream for Western Wisconsin holding primarily Brown Trout from Spring Valley to Elmwood, and Brook Trout downstream from Cady Creek. This trout water is Class II trout water that means fish must be stocked to provide a viable fishery. Below Spring Valley, the stream picks up many smaller brook trout waters including Cady, Mines, and Burkhardt.

During the 1960s the base stream flow of the Eau Galle was 12 cfs (cubic ft. second) with a bottom draw setting of about 10 cfs or 83%. By 1998 the base flow had increased to 22 cfs with the percent of bottom draw unchanged. This resulted in the majority (55%) of water flowing off the top of the reservoir creating downstream water temperatures too warm in summer and too cold in the winter for trout to survive. In addition, a large weir downstream of the dam retained water in a large shallow channel allowing the water to warm further. Downstream stream habitat is in poor shape with high eroding banks.

Documented trout numbers throughout the river below Spring Valley were low (50-350 trout /mile). In contrast, area streams such as the Rush, Kinnickinnic, Plum and Cady Creek have densities of 3,000 to 8,000 trout/mile. Additionally coldwater Index of Biological Integrity (IBI) scores for the Eau Galle were marginal. There is little or no reproduction and survival of stocked trout is poor. Clearly, the temperature of the dam's discharge was severely degrading the Eau Galle's trout fishery. Trout survive in a narrower temperature range than other species.

A "Coldwater Stream" has a mean maximum daily water temperature < 72 F with optimal summer water temperatures for growth and survival of trout between 53.6 -66.2 F. In addition, optimal winter water temperatures for egg and fry development must be between 37 and 55 F. Water temperatures > 81 F is lethal to trout. 

In 1998, the Wisconsin Department of Natural Resources explored an environmental restoration project below the dam to improve trout habitat and restoration on the Eau Galle River. In 1999, the WI DNR gathered data to confirm that thermal problems were impacting the river.

Preferred 53.6 -66.2

Lethal 81.0

Fish Manager Marty Engel established the following trout management goals and objectives for the proposed project.

• Eliminate or reduce water temperature problems that create conditions lethal to trout.
• Reduce number of daily water temperatures > 72 F.
• Provide mean summer water temperatures that in the optimal range for trout.
• Provide winter water temperatures that are optimal for egg and fry development.
• Increase natural reproduction of brown trout and/or substantially improve stock survival.
• Improve downstream habitat.
• Improve trout populations downstream to moderate densities (1500 -3500 trout/mile).

The DNR consulted with the Army Corps of Engineers, City of Spring Valley, Eau Galle-Rush River Sportsman, and Trout Unlimited during the winter of 1999-2000. These discussions led to and implementation plan that incorporated the following points:

• Increase bottom draw from @ 10 cfs to > 18 cfs to improve water temperatures (Summer 2000).
• Remove and replace weir / restore stream channel and habitat (Fall 2003).
• Improve stream habitat through town (Fall 2004).
• Improve habitat downstream from Spring Valley (future).

Over the summer of 2000 the Army Corps of Engineers, in an experimental release, initiated the sub-surface hypo-limnetic release to maximize sub-surface withdrawal to promote a more optimal thermal regime in the river. During this time, the DNR repeated the same thermal monitoring sampling from 1999.

Acknowledgements
Thanks to Gary Horvath, Chapter President of The Kiap-TU-Wish Chapter of Trout Unlimited for permission to reproduce this article on TotalFlyFishing.com. This article cannot be reproduced anywhere else without his consent.

The Kiap-TU-Wish Chapter of Trout Unlimited gets its name from their parent organization and the Rivers of St. Croix and Pierce Counties that they protect....

The Kinnickinnic, Apple -Trout Unlimited - Willow and Rush.

The chapter is actively involved with stream improvement efforts on many of the area steams and is sponsoring leading edge science in the area of the thermal impacts of storm water on the cold water resource. Everyone and anyone are welcome to join them at a stream improvement project or chapter meeting.

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