Poplar River (Lake Superior)

Poplar River
Upper Poplar River Falls
Country	United States
Basin features
Main source	Gust Lake
River mouth	Lake Superior
Basin size	114 square miles (300 km2)
Physical characteristics
Length	21.7 miles (34.9 km)

The Poplar River is a river in northeastern Minnesota that drains into Lake Superior.

The Poplar River derives its English name from a translation of its Ojibwe name. Joseph Gilfillan identified the Ojibwe name of the Poplar River as Ga-manazadika Zibi, or "place-of-poplars river". Thomas Clark further identified the particular poplar in question as the Balm-of-Gilead.

The Poplar River stretches 21.7 miles (34.9 km) from its source in Gust Lake to its mouth in Lutsen, where it empties into Lake Superior. Its major tributaries are Mistletoe Creek, the Tait River, Caribou Creek, and Barker Creek. It drains an area of 114 square miles (300 km²) lying mostly on the Superior Upland plateau. In its upper reaches, the plateau's slope has an average grade of only 1%, which increases to 4% as the Poplar approaches Superior. Due to the many lakes located in this largely flat watershed, Poplar, along with its neighbors the Temperance, Cross, and Cascade rivers, has a more stable flow and a warmer average water temperature. Three miles from its mouth, the Poplar goes over a series of waterfalls. The 2.2 miles (3.5 km) above the Highway 61 bridge at the mouth of the river are classified as class II-IV+(V) rapids.

The Poplar's flow has been modified in the past by dams. In the early 20th century, two dams were located 2.9 and 5.6 miles (4.7 and 9.0 km) above the mouth of the river. In 1923, another dam was installed to power the nearby township of Lutsen, the only hydropower plant on a North Shore stream.

The watershed is 77% forested and 19% wetland, with the remainder being grassland, open water, agricultural land, or bare rock. There are 132 miles (212 km) of streams in the Poplar River watershed, and 87.6 miles (141.0 km) of road.

The lower stretch of the Poplar River serves as a fishery for pink, chinook, and coho salmon in the spring, and rainbow and brook trout in the fall. The largest chinook salmon caught on record in Minnesota was taken here in 1989. 400 feet (120 m) from its mouth, a barrier waterfall prevents Lake Superior fish from traveling any further upstream. Brook trout can be found anywhere in the upper 17 miles of the Poplar, in increasing numbers as one moves further north. In the lower portions, spawning grounds for brook trout are limited by a recent buildup in silt, and warm water temperatures in the summer are stressful on the population. The populations of warmwater species such as smallmouth bass, pumpkinseed sunfish, and bluegill have been increasing in these regions over recent surveys. In the upper watershed of the Poplar, the smallmouth bass has spread into every major lake north of Rice Lake since being introduced into Crescent Lake in the 1990s.