Basin Characterization Model - Simulating Effects of Iowa Soil Management on Water Availability

Science Center Objects

As a result of climate change, heavy rainfall, as well as extended dry periods, are becoming more common in the Midwestern United States. These trends are only expected to continue. So, increasing the capacity of soil to store water has become more critical. Storing water increases availability in dry conditions. And the absorption of additional water in wet conditions reduces potential flooding. Therefore, it is critical to understand how crop- and soil-management strategies can increase soil-water storage to better manage climatic extremes.

Midwest farm landscape

Iowa farm

Prior research in this area has mainly focused on increasing agricultural production. However, through this research it has also been observed that more diverse agricultural practices (i.e. extended crop rotations, cover cropping, perennial crops) can improve water retention in the soil. To understand the impact of such shifts in farming practices on water storage, a method was required to integrate the physical processes of crop growth, the dynamics of water moving through soils, and the influence of rainfall and temperature. To address this need, USGS scientists, working with the Union of Concerned Scientists, developed a Basin Characterization Model. A Basin Characterization Model is a dataset of historical and future hydrologic responses to climate change.

Objectives

The objectives of this project were to create a Basin Characterization Model to provide a better understanding of the future impact of alternative agricultural practices on a regional scale, with an emphasis on soil water. Iowa was chosen as the area to studied because of its extensive use for agriculture and the significant flood and drought events that have occurred over the last several decades.

Science Plan

USGS responsibilities included development of climatology files for the historical record, a selection of files for future projections, and support for ArcGIS (a geographic information system for working with maps and geographic information). Model configuration and changes were made as necessary. Combined Union of Concerned Scientists and USGS responsibilities included regular progress meetings and collaboration for work on final products.

Outcomes

This work directly addressed several aspects of the USGS Science Strategy of “Understanding Ecosystems and Predicting Ecosystem Change, Climate Variability and Change.” Results from the study affirmed that more diversified agricultural landscapes contribute to healthier soils which buffer the negative effects of flood and drought events. Recommendations from the study provided tools and information on hydrologic processes and projected changes throughout the state of Iowa for long-term planning strategies.