Analysis - The Institute for Southern Studies

location restriction mitigation involving karst mitigation and floodplain/wetland mitigation; this probably overly offsets the possible cost
underestimation in this RIA for this regulatory element.
The GIS was based on the DOE-EIA eGRID database to identify the geographic coordinates for 491 of the 495 electric utility plants
(disregarding four plants not present in the eGRID database). Appendix I of this RIA presents site location data for each electric utility plant
used in the GIS analysis. In order to geographically capture both the facilities and their waste units, and to compensate for the fact that there
exists uncertainty as to the exact facility location versus the reported geographic coordinates (i.e., depending on whether location was measured
by plant centroid, street address, smokestack, etc.), this GIS analysis used both a 1-mile and a 3-mile buffer around the reported facility
coordinates. This RIA presumes these buffers are likely to ensure inclusion of the facility's onsite CCR disposal units, and account for
uncertainty in the location data. The 1-mile buffer should capture all impoundments; the 3-mile buffer represents an upper-bound to capture all
landfills that could reasonably be considered on-site.
1. Water table restrictions: GIS analysis not conducted for this site restriction
2. Floodplain restrictions: GIS analysis not conducted for this site restriction
3. Wetlands restrictions: GIS analysis not conducted for this site restriction
4. Fault area restrictions
To identify fault zones, used the USGS database, “Quarternary Fault and Fold Database for the United States,” which contains national scale
location data on faults and associated folds. 57 This analysis identified plants including their buffers which fall within 200 feet of fault lines that
have exhibited movement in the Holocene era. The USGS dataset includes fault lines that are believed to have been a source of earthquakes
greater than magnitude 6 during the Quarternary (the past 1,600,000 years) and it defines “Holocene” as the past 15 thousand years. 58,59
1-mile buffer: 1 plant falls within 200 feet of a fault line.
3-mile buffer: 3 plants fall within 200 feet of a fault line. (these three plants are located in NV and UT).
It is important to note that this preliminary analysis has certain limitations and may not capture facilities in other areas of seismic risk.
According to the USGS fault line database, no relevant faults are located in the central and eastern US. The USGS states in its database
description that this absence of identified faults with movement in the central and eastern US is partly a real phenomena, because the western
US has more tectonic activity, but that it is partly a detection problem caused by geological characteristics present in the central and eastern
US, such as glacial sediments, that conceal evidence of movement along faults. For this reason, the analysis of seismic zones below, which
are defined based on the likelihood of future seismic activity, may represent a more reliable estimate of the number of facilities potentially
affected by fault area restrictions. 60
57 US Geological Survey, 2006, “Quarternary Fault and Fold Database for the United States” at: http//earthquakes.usgs.gov/regional/qfaults. File used: fitarc.shp
58 RCRA defines “Holocene” as “the most recent epoch of the Quarternary period, extending from the end of the Pleistocene to the present” (40 CFR 264.18(a)(2)(iii)).
59
Faults designated by the dataset as showing movement during the Holocene are not necessarily believed to have produced an earthquake of magnitude 6 or greater during
the Holocene. Rather, they are believed to have produced an earthquake of magnitude 6 or greater during the Quarternary, but their most recent suspected movement of any
degree was during the Holocene.
60 The USGS data layer used for this analysis indicates that faults with Holocene movement are located only in states in the West and Southwest regions of the US. This
appears generally consistent with a separate analysis in the RCRA Practice Manual (Garrett, Theodore L., 2004, published by American Bar Association), and the small
number of plants affected is not unexpected given the relatively small number of plants in these regions. However, the RCRA Practice Manual also notes that virtually all
plants in CA and NV, and in parts of AK, AZ, CO, HI, ID, MT, NM, UT, WA, WY would be located within 200 feet of relevant faults. This suggests an upper bound of 54
plants (out of the 491 plants analyzed), if all facilities in the identified states may be affected by fault area restrictions.
71