The Eau Galle RiverA river on the decline, but still holds nice fish.
The Eau Galle River rises in southeastern St. Croix County, a few miles east of the headwaters of the Rush River. It meanders southeastwardly 51 miles through the scenic hills and valleys of northeastern Pierce, southwestern Dunn and northern Pepin Counties, past the villages of Spring Valley and Elmwood. It joins the Chippewa River in Pepin County, about 3 mi southwest of Durand, and is considered part of the Mississippi River watershed. 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 trout, allowed for an excellent fishery. 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.
“The Eau Galle had been included on the state of Wisconsin list of impaired waters.”
For years the Eau Galle above Spring Valley was subject to flash floods from farm run-off that flowed down through gorges. The flood control act of 1954 resulted in a eatherned dam built to control run-off from a 64c mile drainage area of the Spring Valley Area. In 1966, an earthen flood control dam was constructed by the U.S. Army Corps of Engineers to protect the village of Spring Valley. At Spring Valley, the dam causes the Eau Galle to form Eau Galle Lake, also known as Lake George.
The Resource Challenges
The Eau Galle River is a popular place to fish trout, but water quality is threatened by turbidity, natural erosion, and streambank grazing. The Eau Galle River Watershed is frequently polluted by runoff from barnyards and feedlots, and streambank grazing. Flooding also threaten trout streams in the watershed. When the streams flood, large amounts of sediment are moved and the high flows scour the streambeds. This watershed, once almost entirely forested, is now 82 percent agricultural. The Eau Galle River is severely impaired by fine sediment and large-scale bank erosion especially in the Elmwood area. The Spring Valley reservoir (Lake George) receives large amounts of nutrients and sediments from its agricultural watershed. As a result, it experiences frequent summer algal blooms and has extensive aquatic plant growth in shallow areas. Control of sediment, nutrients and stormwater runoff is critical to the improvement of water quality in this reservoir. Reducing the total volume of runoff by increasing infiltration will benefit the Eau Galle River Because of elevated stream temperatures, turbidity, excessive nutrient inputs, sedimentation, and loss of instream habitat, the Eau Galle River is included on Wisconsin’s list of impaired waters.
A River on the Decline
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.
Army Core of Engineer Earthen Dam in Spring Valley.
A “coldwater stream” has a mean maximum daily water temperature < 72º F with optimal summer water temperatures for growth and survival of trout between 53.6 -66.2º F. In addition, optimal winter water temperatures for egg and fry development must be between 37º and 55º F. Water temperatures > 81º 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:
Eau Galle River Restoration
• Eliminate or reduce water temperature problems that create conditions lethal to trout • Reduce number of daily water temperatures > 72º 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).
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.
Kiap-TU-Wish, along with partners such as The Eau Galle Sportsman’s Club, continues to work hard to restore the river through bank stabilization and temperature control, and advocating farming practices that benefit the residents of the area as well as the watershed.