This work was created for a graduate course, CRP 551 Introduction to GIS in 2020.

About the Project Farm fields are an integral part of the Iowa landscape. Rural farm land, as the official land use, makes up 92.6 percent of the land area of the state of Iowa as of 2015. Seemingly simple-looking from the surface, an unknowing observer might consider a farm field a plain patch of dirt. Much less known is that these fields, with their built systems, make up the majority of space within the rural built environment. Today, these spaces are highly designed systems of infrastructure that includes miles of subterranean tile drainage. Through the process of deep mapping, which “allows for the combination of multiple quantitative, qualitative, and multimedia data about a place with the purpose of building a spatial narrative,” this project tells the story of Lake Cairo, a former lake located just northwest of Jewell, Iowa in Hamilton County (See image 1, image 3). Lake Cairo is one example of many in a massive de-centralized and uncoordinated undertaking to drain the northern Iowa landscape of its lakes during the first part of the twentieth-century. This process of change, much within the Des Moines Lobe glaciated area (See image 2), shifted the ecology and land use and put into motion changes that would affect the communities, economy, and the environment of Iowa for decades to come.

Analysis Much of the primary source data used to tell the story of Lake Cairo came from local newspapers, from 1868 to 1961. Over 300 newspaper articles were analyzed and interpreted. Throughout these articles, the exact acreage of Lake Cairo varied wildly from 1,000 acres to 11,000 acres. Water levels, land use change over time, and inaccurate reporting contributed to the confusion. For this project, GIS was used to determine the acreage of the current Lake Cairo lakebed basin. The use of historic maps, aerial photography, General Land Office information, LiDAR, and soil series data from the Iowa Geodata and University of California Davis Soil Series Explorer, in partnership with the Natural Resources Conservation Service of the USDA, were used to accurately measure the current lakebed acreage. Soil series data from both sources were combined in GIS to make an accurate map of the historic Lake Cairo lakebed and surrounding area. The soil series, Blue Earth, speaks to the majority of the historic lakebed of Lake Cairo (See image 7, shown in red). Blue Earth ”consists of very deep, very poorly drained soils that formed in 75 to more than 200 centimeters of coprogenous earth and the underlying loamy till, lacustrine sediments, or outwash of Late Wisconsin glaciation. These soils are on plane or slightly concave slopes in former lake basins in moraines, flood plains, and lake plains (USDA).” By compiling this information into GIS, the final acreage of the lakebed was determined to be 1,450 acres.