15
The water-quality impacts of building a nuclear power plant are similar to those associated with 16
the development of any large industrial site. This section includes identification of the activities 17
associated with building the proposed Lee Nuclear Station Units 1 and 2 that could affect 18
surface and groundwater quality, and analysis and evaluation of proposed practices to minimize 19
adverse impacts on water quality by these activities. The impacts on surface-water and 20
groundwater are discussed in Section 4.2.3.1 and Section 4.2.3.2, respectively. 21
4.2.3.1 Surface-Water-Quality Impacts
22
The activities associated with building proposed Lee Nuclear Station Units 1 and 2 would occur 23
close enough to Ninety-Nine Islands Reservoir that the impacts from these activities on the 24
quality of surface-water need to be considered. The hydrologic alterations associated with 25
building the proposed units, including intakes and discharges, as described in Sections 3.3 and 26
4.2.1, would generally affect surface-water quality by dredging and erosion. Building Make-Up 27
Pond C involves clearing and grubbing, excavation for the dam and abutments, and other 28
activities as described in Section 3.3.1. These activities could result in erosion and sediment 29
and dissolved solids entering the Broad River from the London Creek drainage. The above 30
activities would be regulated by a combination of NPDES and USACE permitting, adoption of a 31
SWPPP, and use of BMPs (for example using cofferdams and silt fences). Installation of the 32
discharge structure within the Federal Energy Regulatory Commission (FERC) Project 33
Boundary Line also requires FERC approval. All necessary mitigation measures required to 34
prevent and/or minimize erosion, sediment and dissolved solids from entering the Broad River 35
will be under the jurisdiction of the FERC. 36
Construction Impacts at the Lee Nuclear Station Site
Draft NUREG-2111 4-16 December 2011
Activities related to road and railroad-spur improvement could potentially affect water quality in 1
London Creek or other small creeks as land clearing and grading increase the potential for 2
runoff and erosion. Storm runoff and water from excavation dewatering in the immediate vicinity 3
of proposed Units 1 and 2 would be managed to drain into Make-Up Pond A, Make-Up Pond B, 4
and the Broad River at permitted outfalls. Duke would use BMPs for soil erosion controls and 5
comply with applicable regulations designed to prevent stormwater runoff from affecting the 6
water quality in the Broad River and small streams in the vicinity of the site (Duke 2009b, c). 7
New transmission lines would need to be installed. Tower and line installation activities would 8
comply with State and Federal guidelines and BMPs would be used to minimize impacts on 9
water quality from erosion and sedimentation. 10
Because the impacts of hydrologic alterations resulting from activities associated with building 11
the proposed units would be localized and temporary, and because the required permits, 12
certifications, and the SWPPP call for the implementation of BMPs to minimize impacts, the 13
review team concludes that the impacts on surface-water quality from activities related to 14
construction and preconstruction of proposed Lee Nuclear Station Units 1 and 2 would be 15
SMALL, and no further mitigation beyond the actions stated would be warranted. NRC- 16
authorized construction activities represent only a portion of the analyzed activities, therefore 17
the NRC staff concludes that the impacts of NRC-authorized construction would be SMALL, and 18
no further mitigation measures beyond the BMPs discussed above, would be warranted. 19
4.2.3.2 Groundwater-Quality Impacts
20
Based on a review of activities that would take place during the building of proposed Lee 21
Nuclear Station Units 1 and 2 and Make-Up Pond C, the review team determined that the 22
impacts on groundwater quality would arise from (1) filling proposed Make-Up Pond C, 23
(2) discharge of groundwater dewatering product, (3) the stormwater management system, and 24
(4) spills. As discussed in Section 4.2.2.2, groundwater would not be used as a water supply 25
source when building at the Lee Nuclear Station site or Make-Up Pond C site (Duke 2009b, c) 26
and there would be no discharges to the groundwater environment during the building period. 27
Saturation of the sediment profile during initial filling of Make-Up Pond C can be expected to 28
result in some dissolution of minerals/metals; however, groundwater quality in wells located 29
near the site of proposed Make-Up Pond C is expected to be similar to that observed at the Lee 30
Nuclear Station site and in the region (see Section 2.3.3.2). During the filling process, water will 31
be pumped from the Broad River and discharged into Make-Up Pond C, which could result in 32
elevated levels of turbidity and suspended solids, both from the water source and erosion and 33
suspension of surface soils at the Make-Up Pond C site. Turbidity and suspended solids levels 34
are expected to improve as inorganic particles settle and organic matter is broken down by 35
microbial activity. Based on the filtering provided by the subsurface environment, the review 36
team determined that any changes to the groundwater quality of wells adjacent to Make-Up 37
Pond C would be minor and temporary. 38
Construction Impacts at the Lee Nuclear Station Site Dewatering of excavations would occur at both sites, (i.e., Lee Nuclear Station and Make-Up 1
Pond C). Ultimately, the dewatering product would discharge to the Broad River at both 2
locations. As discussed above and in Section 2.3.3.2, groundwater in the region includes 3
concentrations of naturally occurring metals as well as pH outside acceptable secondary EPA 4
Drinking Water Standards. Groundwater of this quality naturally discharges to the Broad River 5
and its tributary streams. The estimated volume of dewatering product from the Lee Nuclear 6
Station site is relatively low compared to the flow of the Broad River (see Section 2.3.1.2). 7
Discharge of dewatering product at both the sites would be monitored in accordance with an 8
approved SWPPP prepared by Duke in compliance with a NPDES permit issued by the 9
SCDHEC Bureau of Water. The review team concludes that the dewatering product has a 10
naturally occurring quality, is of small volume, is monitored in accordance with an NPDES 11
permit, and would quickly dilute in the Broad River. The review team also concludes that 12
alteration of groundwater quality from other stormwater management system discharges (e.g., 13
to Make-Up Ponds A or Make-Up Pond B) would be undetectable. 14
BMPs would be applied to prevent spills and minimize their effects. The Spill Prevention, 15
Control, and Countermeasure plan (SPCCP) required by SCDHEC pursuant to 40 CFR Part 16
112 would mitigate impacts on local groundwater because spills would be quickly attended to 17
and not allowed to reach groundwater. Examples of materials that may spill during the building 18
of proposed Lee Nuclear Station Units 1 and 2 are diesel fuel, hydraulic fluid, and lubricants. 19
Because the impacts of filling proposed Make-Up Pond C, and because spills would be 20
localized, temporary, and of limited magnitude, the review team concludes the construction and 21
preconstruction impacts of the proposed action on groundwater quality would be of limited 22
magnitude, localized, and temporary, and therefore SMALL and no further mitigation other than 23
BMPs would be warranted. Because NRC-authorized construction activities represent only a 24
part of the analyzed activities, the NRC staff concludes that impacts to groundwater-quality from 25
NRC-authorized construction activities would be SMALL and no mitigation other than BMPs 26
would be warranted. 27