Analysis - The Institute for Southern Studies

5. Seismic zone restrictions:
To identify seismic zones, USGS National Seismic Hazard Maps provide peak horizontal acceleration at different probabilities of exceedance
in 50 years. 61 Identified those facilities, including their buffers, which overlap with the seismic impact zones that have a 10% or greater
probability of exceeding a maximum horizontal acceleration of 10% the force of gravity (i.e., 0.10 g) in 250 years. 62 The USGS data gives
probabilities of exceedance over 50 years; thus used a data layer presenting 2% probability of exceedance, and assumed that this equates to a
10% probability of exceedance in 250 years.
1-mile buffer: 151 plants fall within seismic zones
3-mile buffer: 152 plants fall within seismic zones
6. Karst zone restrictions:
This analysis used two databases: (1) DOE-EIA’s eGRID database to identify the geographic coordinates of 491 of the 495 plants analyzed
(disregarding four plants that were not present in the eGRID database), and (2) the USGS's GIS database "Engineering Aspects of Karst,"
which provides national-scale data on karst coverage. 63 Four types of karst areas are identified in the dataset: (a) long karst features (fissures,
tubes, and caves over 1000 feet long and 250 feet deep); (b) short karst (fissures, tubes, and caves less than 1000 feet long and 50 feet deep),
(c) areas where karst features are generally absent but present in small isolated areas, and (d) pseudo-karst areas, which have features
analogous to karst.
1-mile buffer: 138 plants fall within karst zones
3-mile buffer: 177 plants fall within karst zones
These counts do not distinguish between the four different types of karst terrain identified in the data set; this analysis represents an initial
upper bound of potentially affected facilities.
Potential Cost for Existing & New Electric Plants to Meet Disposal Unit Location Restrictions
According to the above findings for the three location criteria evaluated in this RIA (i.e., fault areas, seismic zones, karst zones), a maximum
count of 177 plants could be affected (this is the upper-end of the affected plant counts across the three location evaluations). The potential
cost to these plants of the location restrictions is estimated in this RIA using the cost to retro-fit existing CCR disposal units and to protect
new CCR disposal units with a berm (aka levee). A berm is a type of engineering measure which may serve to demonstrate that engineering
measures have been incorporated into disposal unit design to mitigate the potential adverse impacts disposal units may have on, or be caused
by, these six location considerations.
The cost to construct a berm is based on the cost to construct a 10-foot tall flood berm using US Army Corps of Engineers’ publication
“Flood Proofing – How to Evaluate Your Options,” (July 1993), which provides unit costs in 1993 dollars to construct clay core flood control
levees that are two, four, and six-feet high. This RIA inflated these unit costs to 2009 dollars using the ENR Construction Cost Index, and
conducted a regression analysis on the unit costs (i.e., extrapolated the cost based on the implied cost curve of the smaller berms) to estimate
the cost to construct a 10-foot tall berm. The estimated cost per linear foot to construct a 10-foot tall berm is $375. It is assumed that this unit
cost could apply to both existing and new units, and that the berm would be constructed physically separate from the disposal unit, not
integral as “freeboard” to the disposal unit’s structure.
61 U.S. Geological Survey, 2008, “National Seismic Hazard Maps,” from USGS website: http://gldims.cr.usgs.gov/nshmp2008/viewer.htm. Data file used: pga2pct_p.shp.
62
This threshold for seismic impact zones is consistent with RCRA’s municipal solid waste landfill location restrictions (40 CFR 258.14(a)(b)(1)).
63
U.S. Geological Survey, 1984, “Engineering aspects of karst,” from USGS website: http://pubs.usgs.gov/of/2004/1352. File used: karst.shp.
72