The Shell Rock River begins at Albert Lea Lake in Freeborn County in south-central Minnesota, a few miles from the Iowa border. It flows 113 miles into Iowa, where it enters the Cedar River. In Minnesota, the Shell Rock drains 246 square miles (160,000 acres), all in Freeborn County.
The Shell Rock River Watershed, all within Freeborn County, drains 246 square miles (160,000 acres). The lakes, streams and ditches form a chain of water that drains to the river, named for the fossilized shells found along its banks. The Shell Rock River flows about 12 miles from Albert Lea Lake to the Iowa border, where it meanders about another 100 miles into Iowa, where it enters the Cedar River. The Cedar winds its way to the Iowa River, a tributary to the Mississippi River.
The Shell Rock is a headwaters river, meaning it impacts several thousand people downstream who depend on the Shell Rock, Cedar, Iowa and Mississippi rivers for recreation and as a source of drinking water.
Several lakes dot the landscape of the Shell Rock River Watershed, including Pickerel, White, Fountain and Albert Lea Lakes. These lakes are popular for fishing, swimming and boating. Albert Lea Lake, a 2,600-acre shallow lake that draws thousands of waterfowl during spring and fall migrations. Eagles nest year-round on the lake.
Once prairie and wetland, the watershed landscape is now mostly cropland, heavily drained with field tile and drainage ditch systems. Agriculture in the watershed is dominated by corn and soybean row crops.
The Shell Rock River is affected by high levels of phosphorus from regulated and non-regulated sources. Phosphorus causes algae blooms that lead to many problems, including a negative impact to fish and aquatic insects. The algae and resulting poor water quality also make recreation difficult. The Shell Rock River has other water quality problems related to river eutrophication including low dissolved oxygen and high pH levels, along with high bacteria levels at times.
Phosphorus is not just a river problem: Pickerel, Fountain, White and Albert Lea lakes have excessive levels of the nutrient. Algae blooms on many of these lakes impact recreational use.