Understanding the impacts of policy and stakeholder behavior on watershed quality in the Midwest

As a result of widespread and unregulated nonpoint source pollution (NPS), over half of the United States’ surface water bodies are impaired. Excessive nutrient concentrations from agricultural runoff exacerbate toxic algal blooms and eutrophication, which degrade ecosystem health and threaten human well-being. As a critical component of the food, water, energy, and environment (FWEE) nexus, adequate water quality protection necessitates a multi-perspective system approach. While previous research in optimizing agricultural best management practices (BMPs) and modeling watershed nutrient dynamics have provided valuable insight, such approaches often fail to consider their integration with policies and stakeholder perspectives, which influence how water management practices are implemented. To better understand how stakeholder (i.e., farmer, rural community, industry, and gov ernment) behaviors impact water quality, we couple an agent-based model (ABM) and the Soil Water Assessment Tool (SWAT) across several policy scenarios. Examining Illinois’ Upper Sangamon River Basin amidst a lagging cellulosic biofuel economy, we explore how land-use change decisions like the adoption of perennial energy grasses (i.e., miscanthus) in the Midwest can affect water quality. Compared to a “business-as-usual” policy baseline, we illustrate how a scenario that combines environmental and biofuel policy features to encourage miscanthus adoption can reduce nitrate and phosphorus yields by roughly 12% and 10%, respectively, and biochemical oxygen demand (CBOD) by 22% and chlorophyll-a (CHLA) by 10%. Interestingly, scenarios that consider environmental policy components alone do not improve water quality as much as those that integrate biofuel and environmental features together. These simulations convert roughly 5% to 9% of existing land use in the watershed into miscanthus. Additionally, three theoretical scenarios that introduce higher conversion percentages (20%, 25%, and 30%) show enhanced water quality improvement. Through a coupled human-natural system (CHNS) lens, this case study underscores the potential of perennial grasses as a suitable BMP in the Midwest when encouraged by environmental and biofuel policies, and it also reveals a trade-off between nutrient reduction goals and land-use conversion.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Environ Engr in Civil Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Golub, Emma

Contributors dc:contributor

• Cai, Ximing

• Land-use Change
• Swat
• Agent-based Model
• Nutrient Reduction
• Water Quality
• Nonpoint Source Pollution
• Perennial Energy Grass
• Fwee
• Chns
• Best-management Practices

Statement dc:rights

• Copyright 2024 Emma Golub

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/124442

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F124442