Investigating Long-term Nutrient Trends and Short-term Orthophosphate Dynamics in a HUC12 Basin with Extensive Land Use Change

Issue

The Neil Smith Wildlife Refuge was founded in 1990 with the goal of restoring native prairie and savanna ecosystems in Jasper County, IA. Like much of the Midwest, this area’s landscape had long been dominated by traditional agricultural practices. Restoration efforts began in 1993 and have continued extensively over the past three decades. The primary stream running through the Refuge is Walnut Creek, and the large-scale land use change of its watershed (conversion from conventional row crop to native ecosystems) is unique among Midwestern waterbodies, and monitoring data have been continuously collected over the past 30 years. Consequently, Walnut Creek provides a unique opportunity to understand the influence of widespread prairie restoration on downstream water quality.

Objective

This project will provide a 30-year retrospective analysis of this water monitoring data to describe the effect of the Neil Smith Wildlife Refuge’s efforts on downstream water quality. Overall, this project will quantify the impact of Neil Smith Wildlife Refuge on Walnut Creek’s water quality and draw conclusions that can be applied to prairie restoration efforts throughout the Midwest.  

Approach

We will specifically focus on changes to nutrients and sediments in Walnut Creek, as these are some of the pollutants of greatest concern in modern Iowa. The data at Walnut Creek also presents an opportunity to understand better the behavior of dissolved phosphorus, which is the primary cause of most of Iowa’s algae blooms.