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ARS Home » Midwest Area » West Lafayette, Indiana » National Soil Erosion Research Laboratory » Research » Publications at this Location » Publication #360107
Research Project: Conservation Practice Impacts on Water Quality at Field and Watershed Scales

Location: National Soil Erosion Research Laboratory

Title: Impacts of environmental stressors on nonpoint source pollution in intensively managed hydrologic systems

Author
item BOTERO-ACOSTA, ALEJANDRO - University Of Illinois
item CHU, MARIA - University Of Illinois
item Huang, Chi Hua

Submitted to: Journal of Hydrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2019
Publication Date: 8/28/2019
Citation: Botero-Acosta, A., Chu, M.L., Huang, C. 2019. Impacts of environmental stressors on nonpoint source pollution in intensively managed hydrologic systems. Journal of Hydrology. 579:124056. https://doi.org/10.1016/j.jhydrol.2019.124056.
DOI: https://doi.org/10.1016/j.jhydrol.2019.124056

Interpretive Summary: Agricultural practices can cause the degradation of soil and water resources and the negative effects may be further exacerbated by expected changes in climate. Watershed Management Practices (WMPs) are designed to sustain natural resources as well as enhance ecosystem resilience to climate change. This manuscript reports results from model simulations on the impacts of WMPs and projected climate on sediment and nitrate-nitrogen loads in an intensively managed watershed in central Illinois. We found that non-structural WMPs, such as crop rotation and cover crops, were most effective in reducing nitrate and sediment loads. However, structural WMPs can achieve a similar reduction with only treatments implemented in smaller areas. Climate conditions affected pollutant transport mainly due to changes in hydrology. Our findings give a more comprehensive understanding on the impacts of climate change at the watershed scale that can be used to formulate management strategies to increase the resiliency of the ecological system.

Technical Abstract: Agricultural practices intended to increase productivity can adversely affect our soil and water resources. Expected changes in climate and other social pressure are anticipated to exacerbate these impacts jeopardizing the sustainability of the agro-ecosystems. Watershed Management Practices (WMPs) are meant to achieve a rational use of resources as well as enhance ecosystem resilience to climate change. However, the effectiveness of WMPs depends on the complex interactions between processes occurring across the watershed. The objective of this study was to simulate the impacts of WMPs and projected climate on the sediment and nitrate-nitrogen (NO3-N) stream loads in an intensively managed watershed. The modeling framework was developed with the physically-based distributed model Mike SHE for the Upper Sangamon River Basin (USRB), an agricultural watershed in central Illinois. The fate and transport of sediment and NO3-N in the watershed and rivers was simulated using a generic advection-dispersion equation (ADE). Results showed that non-structural WMPs, such as crop rotation and cover crops, presented the highest reductions of simulated NO3-N and sediment load, respectively. However, structural WMPs had higher area-efficiency performance. On the other hand, climate conditions had a strong impact on the transport of both pollutants due to water flux alterations, especially for a future dry climate scenario. Sediment transport was shown to be more sensitive to climate given that rainfall is one of the main drivers of the erosion processes. Outcomes from this research will give a more comprehensive approach toward understanding the impacts of environmental stressors at a watershed scale, and how they may be propagated to ecological systems.