Mosquitoes and the Preservation of Lakes and Wetlands

Rush Lake

When people unaccustomed to living in a wetland took up residence in Palo Alto County in the 1850s, one of the challenges they encountered were mosquitoes on a grand scale.  In warm months cows could not be milked after dusk because the mosquitoes would swarm both cow and human.  People smoked their homes before going to bed for the night trying to keep mosquitoes at bay.  A.C. Haman writes that many newcomers abandoned their claims because of mosquitoes whose presence, they believed, caused them to suffer from an ague. 

            Horses, “tethered and unprotected from mosquitoes at night” could experience not just discomfort but death. Some mosquitoes were vectors for equine encephalitis.  As late as the 1930s, an outbreak of the disease among horses in the Rush Lake area had “devastating effects on the horse population” when horses were still a major source of power on farms. 

            It’s reasonable that newcomers and settlers who stayed in Palo Alto County would want to deny the mosquitoes their wet habitat and drain the sloughs to expose the rich soil beneath.  For many people aspiring to farm in the new state of Iowa, the Swamp Land Act of 1847 provided one pathway and resources to convert 200 million acres of marshlands in Iowa into agricultural fields.  By 2000, 98% of those 200 million acres had been drained.

            But it’s also reasonable to take stock of what was lost with the wetlands and their mosquitoes.  The wetlands teamed with fish, writes A.C. Haman: for example, pickerel, perch, and catfish (huge catfish).  A prime habitat for waterfowl, Iowa provided the nesting grounds for some 3-4 million ducks annually estimated biologist Logan Bennett in the 1930s.

            Although the national Wetlands Act was not passed into law until 1992, enabling $5 million worth of wetlands to be restored on the West Fork of the Des Moines River in Palo Alto County, in 1910 county residents were already thinking ahead.  In that year there was an effort by some to drain what was then called Medium Lake, one of the glacial lakes in the county.  The intent was also to transform it into farm land.  Residents of Emmetsburg launched a protest.  While they were at it, they asked the Executive Council of the State of Iowa not only to spare their lake but all Iowa’s lakes.  They succeeded.  And by order of the Executive Council, Iowa’s lakes were preserved for humans and other species.  Medium Lake was eventually renamed Five Island Lake and became part of Kearny State Park.  The 1944 dedication brochure for the park tells the story of the lake’s preservation and the park’s beginnings.

Sources: SHSI: A.C. Haman, The History of the Rush Lake Area, Part 1, 2000; Dwight G. McCarty papers.