LAND USE and WATER RESOURCES in the MINNESOTA NORTH SHORE DRAINAGE BASIN Carol A. Johnston, Brian Allen, John Bonde, Jim Sal6s
LAND USE AND WATER RESOURCES IN THE MINNESOTA NORTH SHORE DRAINAGE BASIN Carol A. Johnston, Brian Allen, John Bonde, Jim Sal6s, and Paul Meysembourg Natural Resources GIS Laboratory (NRGIS) NRRI Technical Report NRRI/TR-91/07 July 1991 Research funded by the Legislative Commission on Minnesota Resources INTRODUCTION Rivers and streams are an important feature of the Minnesota North Shore. A dozen state parks and waysides lie at the mouths of rivers that cascade down the steep slopes of Minnesota’s northern highlands into Lake Superior,-carving beautiful waterfalls out the basalt bedrock. But the rivers that drain the 5778 km2 North Shore drainage basin provide more than scenic beauty, delivering nutrients and other materials to Lake Superior. Lake Superior’s tributaries provide about half of its annual water input (Bennett 1978), more than 90% of its total dissolved solids, and 68% of its phosphorus (Upper Lakes Reference Group 1977). Moreover, the water from these tributaries is delivered to the nearshore zone, in which Lake Superior’s biological communities are concentrated (Rao 1978, Munawar and Munawar 1978, Watson and Wilson 1978). Since these communities of bacteria, algae, and zooplankton form the basis of the food web, the productivity and integrity of Lake Superior’s waters are heavily dependent on water supplied by the North Shore drainage basin. While some of the materials delivered by rivers and streams are essential to aquatic life, excessive inputs of sediment and nutrients can cause nonpoint source pollution, the flow of pollutants from land to water in stormwater runoff or from seepage through the soil.
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