Regulatory Risk Score

A user’s regulatory risk is calculated based on the zipcodes rainfall/drought risk and its pollution runoff risk. Risk level is provided as low, medium, or high for both risk categories. The sources and methodologies used to create these risk categories is detailed below:

Rainfall/Drought Risk - Rainfall data is obtained from the 30-year average annual rainfall data (1981-2010) from the PRISM group at Oregon State University (PRISM Climate Group, Oregon State University, http://prism.oregonstate.edu, created 10 Jul 2012). ESRI’s ArcGIS software was utilized to calculate zonal statistics and provide the mean average rainfall value within each U.S. zipcode. Zipcodes were then categorized into 3 quantiles and assigned a low value for the top rainfall quantile, medium for the mid rainfall quantile, and high for the bottom rainfall quantile.

Pollution Runoff Risk - Data was obtained from the EPA EnviroAtlas of modeled estimates (2002 study) for dissolved nitrogen in surface runoff from agricultural fields in tons at the watershed level (US Environmental Protection Agency, https://edg.epa.gov/metadata/catalog/search/resource/details.page?uuid=%7Bf8b3f367-e43b-42e5-a4d0-6c8267c782f9%7D, published 19 Aug 2016). ESRI’s ArcGIS software was utilized to calculate the weighted average of nitrogen runoff based on the area of individual watersheds within each zip code. Zipcodes were then categorized into 3 quantiles and assigned a low value for the bottom runofff quantile, medium for the mid rainfall quantile, and high for the top runoff quantile.