Authors: Josh Bendorf*, Iowa State University - Department of Agronomy, Shane Hubbard, University of Wisconsin-Madison - Space Science & Engineering Center, Christopher Kucharik, University of Wisconsin-Madison - Department of Agronomy
Topics: Agricultural Geography, Environmental Science, Geographic Information Science and Systems
Keywords: Agriculture, land use, hydrology, Midwest, precipitation, weather, flooding
Session Type: Guided Poster
Presentation File: No File Uploaded
The Driftless Region is unique to the Midwest because the region was not impacted by the last glaciation, and therefore the area is characterized by many ridges and valleys. Similar to the rest of the Midwest, agriculture is common in the Driftless Region. However, soil degradation and erosion are prone to happen on agricultural land due to the topography. Although conservation practices have been enacted, rapid increases in row crop acreage have been noted in the Driftless Region in recent years. Agricultural land use change was assessed in ArcGIS using the USDA Cropland Data Layer (CDL) from 2006 to 2017. Although this time period is short, substantial row crop expansion of 20,000 acres or more was common across the HUC8 watersheds examined, most of which occurred in the margins on more steeply sloped land, converting existing grasslands, pastures, or alfalfa to row crops. Along with land use change, annual precipitation has been on the rise since the mid-20th century, and extreme hydrologic events (i.e. flooding) are becoming more frequent. A statistical analysis was used to assess the degree of geographic and hydrologic change that has occurred in recent years and to quantify relationships between these trends to assess the environmental impact of the change. Results indicate that precipitation is highly correlated to mean annual stream discharge, while row crop acreage was highly correlated to a five-year running average discharge. This indicates a land use change impacts streamflow longer scales, while annual discharges are related to annual weather patterns.