Data and Code for: Size-Based Regulation and Water Quality: Evidence from the Iowa Hog Industry

Principal Investigator(s):  View help for Principal Investigator(s) Chen-Ti Chen, The Ohio State University; Gabriel Lade, The Ohio State University; John Crespi, Iowa State University; David Keiser, University of Massachusetts Amherst

Version:  View help for Version V1

Version Title:  View help for Version Title V1 [2025-6-24]

Name File Type Size Last Modified
  Replication 06/24/2025 02:11:PM

Project Citation: 

Chen, Chen-Ti, Lade, Gabriel, Crespi, John, and Keiser, David. Data and Code for: Size-Based Regulation and Water Quality: Evidence from the Iowa Hog Industry. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2025-06-24. https://doi.org/10.3886/E234047V1

Project Description

Summary:  View help for Summary
The growing prevalence of animal feeding operations (AFOs) in the United States raises concerns among the public and regulators about their impact on local environmental quality. By linking historical regulatory records of AFOs in Iowa to downstream surface water pollution monitors, this paper studies the effects of 2003 Clean Water Act regulations that targeted water pollution from the largest hog AFOs. The regulation decreased ammonia concentrations downstream of large hog AFOs by 6 to 8 percentage points. We find limited to no evidence of improvement for dissolved oxygen and phosphorus concentrations. Pollution reductions are largest during heavy precipitation months, consistent with the regulations reducing on-site spills and nutrient runoff from local fields. However, we find that pollution increased downstream from mid-sized hog AFOs, which were exempt from the updated regulations. Given the growth in the number of mid-sized facilities relative to large AFOs, we estimate that the regulation had little discernible impact on overall water quality.

Scope of Project

Subject Terms:  View help for Subject Terms Clean Water Act; Concentrated Animal Feeding Operations; size-based regulation; surface water quality
Geographic Coverage:  View help for Geographic Coverage Iowa
Time Period(s):  View help for Time Period(s) 2000 – 2012


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V1 [2025-06-24]

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