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<br />24 BIOLOGICAL REPoRl' 19
<br />
<br />Corps of Engineers began dredging a I-m-deep
<br />navigation channel through the downstream 40
<br />km of the mainstem. A wingdam was constructed
<br />in 1910 near St. Mary's Point, and by 1938 the
<br />navigation channel had been deepened to its pre-
<br />sent depth of 3 m. Commercial barge traffic
<br />peaked at 120 tows/year in the early 1970's (Wa-
<br />ters 1977). Today, barge traffic has nearly ceased,
<br />largely because of the Allen King Power Plant
<br />near Stillwater, Minnesota, switching to rail for
<br />coal transport and to the closing of a nearby fer-
<br />tilizer plant, but is virtually non-existent today.
<br />Several hydroelectric dams still produce a few
<br />megawatts of electricity during peak demands,
<br />but the St. Croix River today is primarily a recrea-
<br />tional resource.
<br />In 1968, 165 kIn of the St. Croix River upstream
<br />of the Taylors Falls Dam and 157 km of the Namek-
<br />agon River were (combined) one of eight streams or
<br />reaches in the United States to be approved as part
<br />of the National Wild and Scenic Rivers System. In
<br />1972, the lower 87 km of the St. Croix River were
<br />added to this system. The so-called riverway corri-
<br />dor averages about 0.4 km of land on either side of
<br />the stream channel. The National Park Service's
<br />management plan for the riverway corridor is re-
<br />stricted by the National Wlld and Scenic Rivers Act
<br />to acquiring no more than 25 ha/ kIn by fee (U.S.
<br />National Parks Service 1976a, 197Gb). At present,
<br />there are 37,500 ha along 409 km of the St. Croix
<br />and Namekagon rivers that are designated as the
<br />St. Croix National Scenic Riverway, and 86% of this
<br />land is under federal, state, or local zoning control
<br />(Victoria Grant, U.S. National Park Service, St.
<br />Croix Falls, Wisconsin, personal communication).
<br />The reach upstream of the impounded waters at
<br />Taylors Falls to the headwaters of the St. Croix and
<br />Namekagon rivers and the reach extending 16 km
<br />downstream from the Taylors Falls Dam are desig-
<br />nated "scenic," while the impounded waters and
<br />remainder of the lower St. Croix River are desig-
<br />nated "recreational." The National Park Service is
<br />the federal management agency for the Wild and
<br />Scenic Rivers System and, therefore, makes rules
<br />and policy for the entire St. Croix-Namekagon
<br />river corridor. According to Waters (1977), the St.
<br />Croix River is "... the outstanding recreational river
<br />resource of the Upper Midwest."
<br />The objective of this paper is to provide (1) a
<br />summary of the geologic formation of the river
<br />valley and its drainage basin; (2) a brief analysis of
<br />recent land-use and vegetative-cover patterns; (3)
<br />a summRry of surface water quality in the basin and
<br />
<br />its relation to geologic features, land-use, and vege-
<br />tative-cover patterns; (4) a listing of aquatic biota
<br />within the basin; and (5) an evaluation of the status
<br />of the fish community. Issues of concern are identi-
<br />fied, and recommendations for future plRnning,
<br />m~magement, and protection of St. Croix River
<br />resources are presented.
<br />
<br />Characterization of the River
<br />and its Basin
<br />
<br />Physiography
<br />
<br />The St. Croix River is a sixth-order stream that
<br />drains a 2O,018-km2 area (L. G. Perry, Wisconsin
<br />Department of Natural Resources (WDNR), Madi-
<br />son, personal communication) in east-central Min-
<br />nesota and northwestern. Wisconsin (Fig. 1). The
<br />river begins at the outlet of Upper St. Croix Lake
<br />(346 ha) near Solon Springs, Wisconsin, and flows
<br />276 km southwest and then south to its confluence
<br />with the Mississippi River at Prescott, Wisconsin
<br />(Fago 1986). It forms the border between Wisconsin
<br />and Minnesota for the last 210 km. One 4-m-high
<br />dam at Gordon, Wisconsin, impounds 774 ha of
<br />water in the mainstem of the St. Croix River, and
<br />another 18-m-high hydroelectric dam, which spans
<br />the river between St. Croix Falls, Wisconsin, and
<br />Taylors Falls, Minnesota, impounds 314 ha (Fig. 1).
<br />An old logging dam (Never's Dam, formerly located
<br />about 18 km upstream from Taylors Falls) was
<br />removed in 1955 (Daniels 1990). The rest of the
<br />river is free-flowing, although the final 26.4 km of
<br />the mainstem is a 1,889-ha natural lake (Lake St.
<br />Croix).
<br />The average gradient of the St. Croix is 0.47
<br />m/km. The 129-km reach from the headwaters
<br />down to the bridge on Highway 70 near
<br />Grantsburg, Wisconsin, averages 0.56 m/km and
<br />is steepest (1.05 m/ km) in the Kettle River Rapids,
<br />a 13-km reach near the mouth of the Kettle River
<br />(Fig. 1). From Grantsburgto Taylors Falls, the river
<br />gently meanders through the low relief of the
<br />Anoka Sand Plain, and the average gradient falls
<br />to 0.15 m/km. The river in the vicinity of Taylors
<br />Falls used to include a 10-km reach of steep rapids
<br />(1.81 m/ km) that were known as St. Croix Falls
<br />(Underhill 1955); however,these rapids have been
<br />inundated since 1909 by the Taylors Falls Dam.
<br />From the dam to the beginning of Lake St. Croix,
<br />near Stillwater, Minnesota, the gradient is reduced
<br />to 0.09 m/km.
<br />
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