5.0 ENVIRONMENTAL IMPACTS OF STATION OPERATION

Transcription

1 Land Use Impacts 5.0 ENVIRONMENTAL IMPACTS OF STATION OPERATION 5.1 LAND USE IMPACTS The following sections describe the impacts of Callaway Plant Unit 2 operations on land use at the Callaway Site, the 8 mile (13 km) vicinity, and associated transmission line corridors, including impacts to historic and cultural resources. The operation of Callaway Plant Unit 2 is not anticipated to affect any current or planned land uses THE SITE AND VICINITY Land use impacts from construction are described in Section The only additional impacts to land use from operations will be the impacts of solids deposition from cooling tower drift. The cooling system for Callaway Plant Unit 2 is a closed-cycle, wet cooling system, consisting of two natural draft hyperbolic cooling towers for heat dissipation. Each tower is approximately 550 ft (168 m) high with a base and top diameter of 414 ft (126 m) and 242 ft (74 m), respectively. The distance between these two identical cooling towers is approximately 500 ft (152 m). Makeup water for the units is taken from the collector wells at an average rate of 24,160 gpm (91,446 lpm), assuming 4.8 cycles of concentration. The cooling tower system occupies an area of approximately 15 acres (6.1 hectares). Details of cooling tower design are discussed in Section and impacts of the heat dissipation system, including salt deposition, are discussed further in Section and Section The cooling tower to the south (the first unit) and the cooling tower to the north (the second unit) for Callaway Plant Unit 2 are located east and northeast of the Callaway Plant Unit 2 power block, respectively. The first and second cooling towers are approximately 5,826 ft (1,776 m) and 5,108 ft (1,557 m), respectively, from the center of the tower to the nearest property line. The wind driven cooling tower plume could occur in all compass directions. The maximum salt deposition rate from the cooling towers is provided in Table The predicted deposition rate is below the NUREG-1555 (NRC, 1999) significance level for possible vegetation damage of 8.9 lbs per acre per month (10 kg per hectare per month) in all directions from the cooling towers, during each season and annually. Therefore, impacts to vegetation from the salt deposition are not expected for both onsite and offsite locations. Previous studies (Union Electric, 1985 and Applied Biology, Inc., 1986, 1987, 1991, 1993) reported that the Callaway Plant Unit 1 cooling tower drift revealed no evidence of adverse impacts to vegetation. The drift from the Callaway Plant Unit 2 cooling towers is much less than the drift from the Callaway Plant Unit 1 cooling tower. Based on these facts, no impacts affecting land-use pattern are expected from the operations of the new cooling towers. The average plume length and height was calculated from the frequency of occurrence for each plume by distance from the tower. The average plume length ranges from 0.36 miles (0.6 km) to the south in the summer season, to 2.6 miles (4.2 km) to the southeast in the winter season. The annual average plume length is 1.2 miles (2.0 km) to the southeast. The average plume height above the tower ranges from 490 ft (150 m) in the summer season to 1,900 ft (570 m) in the winter season. The annual average plume height is 1,000 ft (320 m). Due to the varying directions that the plume travels and short average plume height and length, impacts from elevated plumes would be SMALL and would not warrant mitigation. The electrical switchyard for Callaway Plant Unit 2 is located approximately 1,960 ft (600 m) to the southwest of the location for the circulating water supply system (CWS) cooling towers. A Callaway Plant Unit Rev. 1

2 Land Use Impacts maximum predicted solids deposition rate of lbs per acre per month ( kg per hectare per month) is expected at the Callaway Plant Unit 2 switchyard. Additionally, the electrical switchyard for Callaway Plant Unit 1 is located approximately 2,800 ft (853 m) to the south-southwest, from the location of the Callaway Plant Unit 2 CWS cooling towers. The maximum predicted solids deposition expected at the Callaway Plant Unit 1 electrical switchyard due to operation of the Callaway Plant Unit 2 CWS cooling tower is lbs per acre per month ( kg per hectare per month). Based on industry experience, adjustments to maintenance frequencies (e.g., insulator washing) may be necessary due to solids deposition; however, the expected deposition rates will not affect switchyard component reliability or increase the probability of a transmission line outage at Callaway Plant Unit 1 or Callaway Plant Unit 2. Table shows the extent of solids deposition during the summer months. Impacts from salt deposition from the Callaway Plant Unit 2 cooling tower will be SMALL. Section , Terrestrial Ecosystems, presents information on the sensitivity of specific species to salts. Section 2.2.1presents land use on the Callaway Site and its vicinity extending 8 miles (13 km) from the site midpoint and includes maps showing land use and transportation routes. Land use across the entire Callaway Site is shown in Table and discussed in more detail in Section 2.2. Grassland is the most common land use at the Callaway Site and represents 43% of the Callaway Site acreage. The next highest land use category is forest. The forested area, including deciduous forest and evergreen forest, represents 27% of the Callaway Site acreage. High intensity urban/built-up is the least land use area classification at the Callaway Site and represents less than 0.1% of the Callaway Site acreage. Land use data for the 8 mile (13 km) site vicinity is presented in Table and discussed in more detail in Section 2.2. Forest, including deciduous forest and evergreen forest, is the largest land use category and represents approximately 53% of the area in the 8 mile (13 km) site vicinity radius. Grassland is the next largest land use and represents approximately 21% of the land area, with the Urban/Built-up category representing 0.33% of the land area. As described in Section 2.5, the impact evaluation assumes that the residences of Callaway Plant Unit 2 employees will be distributed across the region in the same proportion as those of the Callaway Plant Unit 1 employees. It is estimated that an additional operational work force of 363 onsite employees will be needed for Callaway Plant Unit 2. Section describes the impact of 363 new employees on the region s housing market and the increases in tax revenues. Up to 1,500 additional workers are required during refueling outages. These additional workers typically fill the local hotels or occupy available RV spaces. This occupancy is consistent with the designated uses for the land and, therefore, does not result in any adverse impacts to land use. Approximately 90% (330) of the new employees are expected to be drawn from or settle in Callaway County, Cole County, or Boone County. Forty-nine percent (423) of current Callaway Plant Unit 1 employees live in Callaway County. The county is mostly rural, with public utilities and amenities generally available in the larger municipalities. It is likely that the new employees who choose to settle near the Callaway Site will purchase homes or acreage in the Callaway County, Boone County, or Cole County area. Based on the 22 years of experience with the existing unit, increased tax revenues will not spur development in the vicinity of the Callaway Site. Callaway Plant Unit Rev. 1

3 Land Use Impacts It is therefore concluded that impacts to land use in the vicinity will be SMALL and will not warrant mitigation TRANSMISSION CORRIDORS AND OUTSIDE AREAS As discussed in Section 2.2.2, the additional power generated by Callaway Plant Unit 2 will be transmitted along the existing unit/system and a new offsite transmission corridor developed adjacent to the existing transmission corridor. It requires widening existing 200 ft (61 m) wide right-of-way by 150 ft (46 m). New transmission towers supporting a 345 kv transmission line are installed in the widened corridor to the west of and parallel to the existing transmission lines. These lines carry power south from the switchyard through the Corridor Area of the Callaway Site property, and cross State Route 94 on the north side of the River, cultivated land within the Missouri River floodplain, the Missouri River at river mile 116.6, and State Route 100 on the south side of the River. The transmission line ends at a tie in point 6.7 miles (10.8 km) south of the Callaway Plant Unit 1 switchyard. Callaway Plant Unit 2 construction activities are discussed in Section Line routing avoids or minimizes impact on forests, grasslands, wetlands, and threatened and endangered species identified in the local area. No operational land use impacts will occur as the result of the operation of the new transmission lines or the Callaway Plant Unit 2 substation. In general, the transmission line owner (AmerenUE) ensures that land use in the corridors and underneath the high voltage lines is compatible with the reliable transmission of electricity. Vegetation communities in these corridors are kept at an early successional stage by mowing and application of herbicides and growth-regulating chemicals. In some instances, AmerenUE could allow agricultural activities in these rights-of-way. AmerenUE will also allow public recreational use with limitations on company-owned and Missouri Department of Conservation (MDC)-managed property, and individuals to exercise their rights of ownership in right-of-way outside of Ameren owned land, subject to negotiated agreements. However, AmerenUE s control and management of these rights-of-way precludes virtually all residential and industrial uses of the transmission corridors. As described in Section 3.7, AmerenUE has established corridor vegetation management and line maintenance procedures that will continue to be used to maintain the corridor and transmission lines. There is no need for additional access roads along the existing offsite transmission corridors. Offsite corridor maintenance activities will be in accordance with existing right-of-way agreements between AmerenUE and current landowners, where applicable. Should additional access be warranted, AmerenUE will negotiate/renegotiate access agreements with the appropriate landowner. Therefore, it is concluded that land use impacts to offsite transmission corridors from operation of Callaway Plant Unit 2 will be identical to impacts from the existing Callaway Plant Unit 1. Onsite transmission corridor construction activities are discussed in Section 4.1. The basic transmission system electrical and structural design parameters for this new onsite transmission corridor are addressed in Section 3.7. Land use impacts from construction of the new onsite transmission corridor and new Callaway Plant Unit 2 switchyard are described in Section 4.1. Following construction, permanent impacts include the maintenance of the 150 ft (45.7 m) wide corridor as a grassed or farmed use rather than wooded. Since the new towers are placed within 150 ft (45.7 m) of the current towers, visual impacts are SMALL, particularly when viewed from a distance. As there are no residences in the immediate vicinity of the transmission towers, no other impacts (i.e., from electromagnetic forces or noise) are expected. Callaway Plant Unit Rev. 1

4 Land Use Impacts It is therefore concluded that impacts to land use in the existing transmission corridors or offsite areas would be SMALL and would not require mitigation HISTORIC PROPERTIES AND CULTURAL RESOURCES Table and Table list historic properties within the project Areas of Potential Effect that are potentially eligible or eligible for listing on the National Register of Historic Places (NRHP). A total of approximately 97% of the Callaway Site has been surveyed for the presence of cultural resources. As described in Section 2.5.3, the cultural resource survey of the Callaway Site identified 79 prehistoric sites and 29 historic sites, of which a total of 20 were evaluated as eligible for inclusion on the National Register of Historical Places. The survey also identified 19 architectural resources, none of which are considered eligible for the National Register of Historical Places. Steamboat wrecks circa late 19th century may exist on the Callaway Site property in the vicinity of the Mollie Dozier Chute, near the location of the collector well system. Historical maps indicate at least five steamboat wrecks in this area, most likely buried deeply underneath floodplain alluvium. In accordance with a monitoring plan approved by the Missouri State Historic Preservation Office (SHPO), a qualified archaeologist monitored all drilling activities in this area. The nearest drilling location was placed approximately 0.5 miles (0.8 km) from the locations of known steamboat wrecks. No evidence of steamboat wrecks was identified during the monitoring program. The eligible sites are located at least one mile (1.6 km) from the Callaway Plant Unit 1 cooling tower and are not near the identified construction limits for Callaway Plant Unit 2. These sites are preserved in place by AmerenUE. Monitoring for and handling of historic properties and cultural resources will be addressed during construction as described in Section Currently, construction and operation of Callaway Plant Unit 2 is expected to have no effect on these resources. However, should historic properties or cultural resources be identified during additional investigation and monitoring prior to and during construction, they will be handled in accordance with a standard operating procedure which has been reviewed and approved by SHPO. Maintenance activities will occur in areas previously disturbed during Callaway Plant Unit 2 construction, none of which contain eligible archaeological resources. Thus, effects on such properties from maintenance activities are expected to be SMALL and not warrant mitigation. As discussed in Section , operation of cooling towers might produce a visible plume, occasional fog and ice, and salt deposition which could affect the settings or materials of historic properties. However, operational impacts of rime icing and ground fogging can occur but are not associated with natural draft cooling towers. Therefore, the operational impacts related to icing and fogging are expected to be SMALL and not warrant mitigation. Due to the sparsely populated nature of the project vicinity, and the fact that a natural draft cooling tower currently exists on the project site, visual impacts are expected to be SMALL and not warrant mitigation. Effects on the property from salt deposition could occur but are expected to be SMALL and not warrant mitigation due to the small amount that would be deposited in the area ( lbs per acre per month ( kg per hectare per month)). Previously recorded historic or archaeological resources located within 10 miles (16 km) of the Callaway Site were also identified through research of existing records. Archaeological sites are abundant within the 10 mile (16 km) radius, although the majority have been reported by local residents and not surveyed by archaeologists. Two regionally important prehistoric sites are listed on the NRHP, as discussed in Section These resources are provided in Appendix A of Section 2.5. Potential sources of effects on these resources would be operation of the cooling Callaway Plant Unit Rev. 1

5 Land Use Impacts towers and the resulting fog, ice, and the visible plume. There is a high probability that undiscovered prehistoric sites are present within the 10 mile (16 km) radius of the Callaway Site, primarily Native American mounds associated with prehistoric villages. There are no historic archaeological sites listed on the NRHP within the 10 mile (16 km) radius of the Callaway Site. Because significant fogging and icing are not likely to occur with natural draft cooling towers, any adverse effect on offsite historic properties and their settings or materials would be SMALL and not warrant mitigation. The plume above the cooling tower would be visible from archaeological and historic resources in the region surrounding the Callaway Site and would introduce a modern feature into their viewsheds. However, due to the presence of numerous modern features in the region already, the effect on these properties would be anticipated to be SMALL and not warrant mitigation. With maintenance and operations activities, there is always the possibility for inadvertent discovery of previously unknown cultural resources or human remains. Prior to initiating land disturbing activities, procedures will be developed which include actions to protect cultural, historic, or paleontological resources or human remains in the event of discovery. These procedures would comply with applicable Federal and State laws including the National Historic Preservation Act (USC, 2007) and the applicable sections of the Revised Statutes of Missouri (RSMo) Chapters 194 (RSMo, 2006a) and 253 (RSMo, 2006b). The use of the transmission corridors by the project would not result in new impacts to cultural and historical resources. Should there be a need for ground disturbing activities during maintenance in the transmission corridor, Phase I surveys will be conducted in accordance with SHPO guidelines. Should new and significant cultural and historic resources be encountered along the transmission corridors, AmerenUE would contact the Missouri SHPO to consult on the discovery. It is therefore concluded that Callaway Plant Unit 2 operations would have a SMALL impact on historic or cultural resources and would not require mitigation REFERENCES Applied Biology, Inc., 1986, Aerial Photographic Monitoring and Interpretation of Vegetation at Callaway prepared for Union Electric Company, St. Louis, Missouri, October Applied Biology, Inc., 1987, Aerial Photographic Monitoring and Interpretation of Vegetation at Callaway prepared for Union Electric Company, St. Louis, Missouri, October Applied Biology, Inc., 1991, Aerial Photographic Monitoring and Interpretation of Vegetation at Callaway prepared for Union Electric Company, St. Louis, Missouri, November Applied Biology, Inc., 1993, Aerial Photographic Monitoring and Interpretation of Vegetation at Callaway prepared for Union Electric Company, St. Louis, Missouri, November NRC, Environmental Standard Review Plan, NUREG-1555, Nuclear Regulatory Commission, October RSMo, 2006a, Title XII Missouri Revised Statutes, Public Health and Welfare, Chapter 194, Death - - Disposition of Dead Bodies, August RSMo, 2006b, Title XVI Missouri Revised Statutes, Conservation, Resources and Development, Chapter 253, State Parks and Historic Preservation, August Callaway Plant Unit Rev. 1

6 Land Use Impacts Union Electric, 1985, Aerial Photographic Monitoring and Interpretation of Vegetation at Callaway, Environmental Services Department, Union Electric Company, St. Louis, Missouri, August USC, Title 16, United States Code, Part 470, National Historic Preservation Act of 1966, as amended, Callaway Plant Unit Rev. 1

7 Land Use Impacts Table Land Use at the Callaway Site Land Use Land Cover Class Acres Hectares Percent of Total Area Impervious % High Intensity Urban % Low Intensity Urban % Cropland % Grassland 1, % Deciduous Forest % Evergreen Forest % Deciduous Woody/Herbaceous % Herbaceous-Dominated Wetland % Open Water % REFERENCES: Missouri Spatial Data Information Service (MSDIS) web site, Accessed September 27, Callaway Plant Unit Rev. 1

8 Land Use Impacts Table Land Use Within the 8 mile (13 km) Radius of the Callaway Site Land Use Land Cover Class Acres Hectares Percent of Total Area Impervious 1, % High Intensity Urban % Low Intensity Urban % Cropland 22,027 8, % Grassland 26,672 10, % Deciduous Forest 65,008 26, % Evergreen Forest 3,092 1, % Deciduous Woody/Herbaceous 1, % Woody-Dominated Wetland 3,764 1, % Herbaceous-Dominated Wetland % Open Water 3,916 1, % REFERENCES: Missouri Spatial Data Information Service (MSDIS) web site, September 27, Callaway Plant Unit Rev. 1

9 Water Related Impacts 5.2 WATER RELATED IMPACTS This section identifies impacts to surface water and groundwater resources associated with operation of Callaway Plant Unit 2 and transmission corridors. As described in Section 3.3, Callaway Plant Unit 2 requires water for cooling and operational purposes. Sources for this water include the Missouri River/Missouri River Alluvial Aquifer (Aquifer) provided via a Collector Well Rive.r Intake System and the Cambrian-Ordovician aquifer via deep onsite water supply wells. Water from the collector wells provides makeup water for plant cooling, and the wells supply makeup water for power plant operations. Normal plant operations require an estimated 22,283 gpm (84,340 lpm) of aquifer water for turbine condenser cooling. Approximately three-fourths of this water will be lost to the atmosphere as evaporation and cooling tower drift, and the other one-fourth will be released as blowdown. Water from the Aquifer provides non-safety-related makeup water to the ESWS cooling tower water storage basins at an average rate of 1,882 gpm (7,123 lpm) under normal operating and normal shutdown/cooldown conditions. The makeup water serves to replenish water losses due to cooling tower evaporation and drift at a rate of 940 gpm (3,558 lpm) and 2 gpm (8 lpm), respectively. The remaining water is released to the Missouri River as ESWS cooling tower blowdown at an average rate of 940 gpm (3,558 lpm) HYDROLOGIC ALTERATIONS AND PLANT WATER SUPPLY Section 2.3.1provides a description of surface water bodies and the groundwater aquifers, including their physical characteristics Regional Water Use Section describes surface water and groundwater uses that could affect or be affected by the construction or operation of Callaway Plant Unit 2. Section describes the potential sources of surface water, the current and future consumptive surface water uses in Callaway County, and the non-consumptive surface water uses. Section describes the sources of groundwater available to the Callaway Site and the current and future trends in groundwater use in the central Missouri region, in Callaway and Osage Counties, and by Callaway Plant Unit 1. The standards and regulations applicable to the use of surface water are presented in Section The groundwater demands, monitoring of groundwater levels, and the ongoing comprehensive assessment of groundwater resources in the central Missouri region are described and discussed in Section Plant Water Use The following sections describe sources and uses of water associated with Callaway Plant Unit 2. Additional detail on water sources, rates of consumption and return, and amounts used by various plant operating systems during normal operations and outages is presented in Section 3.3. Peak water demand from the Aquifer during normal operations is estimated at 34,305 gpm (129,844 lpm). During refueling outages, which occur every 18 to 24 months and last approximately 1 month, the maximum water demand will decrease to essentially only the shutdown cooling, miscellaneous refueling water and fresh water demands for the onsite workforce. Callaway Plant Unit Rev. 1

10 Water Related Impacts During Callaway Plant Unit 2 outages, the permanent onsite workforce including Callaway Plant Unit 1 of approximately 1,200 would increase by an estimated 1,000 additional workers. For the purpose of estimate, a fresh water demand value of 30 gpd (114 lpd) per person is assumed. Using this value, fresh water demand would increase from 25 gpm (95 lpm) during normal operations, to 46 gpm (174 lpm) during major outages. Sanitary effluents are estimated at 20 gpm (76 lpm) during normal operations, and would increase to 45 gpm (170 lpm) during major outages. The fresh water demand increase represents a relatively small fraction of the deep well water capacity, which is approximately 965 gpm (3,650 lpm) Surface Water Callaway Plant Unit 2 is designed to use the minimum amount of water necessary to ensure safe, long-term operation of the plant. Installation of a collector well river intake system is planned to supply makeup water for Callaway Plant Unit 2 as well as Callaway Plant Unit 1, which currently uses a surface water intake structure. The collector wells are located at the Missouri River/Missouri River Alluvial Aquifer ( aquifer ) interface approximately 1.5 river miles (2.4 km) upstream of the original Callaway Plant Unit 1 intake structure. The Callaway Plant Unit 2 discharge combines with the discharge from Callaway Plant Unit 1 and flow to the Missouri River through the existing 36 inch (91 cm) diameter blowdown pipe. Additional details on the intake and discharge systems are presented in Section 3.4. Water withdrawals for the operation of Callaway Plant Unit 2 are described in detail in Section Plant Construction The primary water demands during construction are concrete mixing and curing, dust control, and potable water. Water for construction will come from the existing water supply well (Well #3) which is presently used for potable water, and two inactive wells (Wells #1 and #2) which will be re-activated during construction activities, as discussed in Section 4.2. Estimated average construction water demand is 250 gpm (946 lpm) during working hours (i.e. 8 hours per day, 285 days per year), and the peak water use is estimated at 700 gpm (2,660 lpm). Construction uses of water are described in more detail in Table Construction water use is assumed to be entirely consumptive. Groundwater withdrawals required for construction of Callaway Plant Unit 2 will cause small and localized impacts on the aquifer water levels. Section 4.2 further addresses construction supply requirements and potential impacts to groundwater aquifers during construction Circulating Water Supply System Callaway Plant Unit 2 utilizes a closed-loop Circulating Water Supply System (CWS). The system uses two natural draft cooling towers for heat dissipation. The CWS cooling towers have the same basic structure and profile as the cooling tower for Callaway Plant Unit 1. The cooling tower system requires makeup water to replace that lost to evaporation, drift (entrained in water vapor), and blowdown (water released to purge solids). Makeup water for the natural draft CWS cooling tower system is withdrawn from the Aquifer. As indicated in Section 3.4, makeup water for the CWS is pumped at a maximum rate of 29,886 gpm (113,118 lpm). At the maximum makeup rate, water lost by evaporation and blowdown returned to the Missouri River is approximately 19,924 gpm (75,412 lpm) and 9,954 gpm (37,676 lpm), respectively. Average makeup water flow to the Circulating Water Supply System is expected to be approximately 22,283 gpm (84,340 lpm), with water lost by evaporation and blowdown returned to the Missouri River being approximately 17,607 gpm (66,644 lpm) and 4,667 gpm (17,666 lpm), respectively. Callaway Plant Unit Rev. 1

11 Water Related Impacts The water balance is affected minimally by drift. Maximum drift losses are less than 0.001% of the circulating water flow (806,730 gpm (3,053,473 lpm)). This results in a maximum drift of 8 gpm (31 lpm). The cooling tower operates at approximately 5 cycles of concentration. The Essential Service Water System (ESWS), under normal plant operations with two trains operating, operates at a nominal recirculated flow rate of approximately 19,200 gpm (72,680 lpm). The average fresh water makeup rate for the ESWS required under normal operations is estimated to be 1,882 gpm (7,124 lpm) to offset maximum evaporation rate (approximately 940 gpm (3,558 lpm)), maximum blowdown rate (approximately 940 gpm (3,558 lpm)), and drift loss (approximately 2 gpm (8 lpm)). Water released to the Missouri River as blowdown is not lost to downstream users or downstream aquatic communities. Evaporative losses and drift losses are not replaced and are considered consumptive losses Missouri River Collector Wells A collector well system in the Missouri River/Missouri River Alluvial Aquifer (Aquifer) supplies makeup water for plant cooling. The collector well system supplying makeup water for Callaway Plant Units 1 and 2 consists of approximately three collector wells distributed along the edge of the Missouri River spaced approximately 1,500 ft (460 m) apart to limit interference of water production among wells. It is expected that 85% of the water will be derived from surface water recharge to the aquifer, while 15% will be derived from upgradient sources of groundwater. The combined pumping flow rate from the Aquifer for Callaway Plant Unit 2 is a maximum of approximately 34,305 gpm (129,844 lpm). The description of collector wells is presented in Section 3.4. Water use from the Aquifer for plant cooling is described in detail in Section Groundwater Use Groundwater monitoring wells were installed on the site and surrounding area to evaluate the groundwater in the Callaway Site vicinity as described in Section Groundwater withdrawals will be used to support operation of Callaway Plant Unit 2 as described in Section 3.3. Water from the Aquifer will provide makeup water for plant cooling and onsite deep wells will supply makeup water for power plant operations. As explained in Section 2.3.2, projected average needs for Callaway Plant Unit 2 operation (after construction) are 20 gpm (76 lpm) for potable water, 3 gpm (11 lpm) for fire water, and 80 gpm (303 lpm) for demineralization makeup water. Groundwater withdrawals during construction are discussed in Section 4.2. As discussed in Section 2.3.1, temporary groundwater dewatering controls may be required during construction activities; however, a permanent groundwater dewatering system is not a design feature for the Callaway Plant Unit 2 facility Hydrological Alterations Operational activities that could result in hydrological alterations within the site and vicinity and at offsite areas are described in Section 3.3, Section 3.4, and Section 3.7. The principal hydrological alteration onsite associated with Callaway Plant Unit 2 will occur during construction, when at least one stormwater runoff pond is filled, and some wetlands and wetland buffers are lost (refer to Section 4.2 for detailed discussion on construction impacts). Some onsite streams may be impacted by either sedimentation or reduced water flow due to measures taken to reduce sedimentation, as described in Section Once construction is completed and normal operations begin, it is expected that the streams will experience little ongoing impact. Callaway Plant Unit Rev. 1

12 Water Related Impacts There have been no clearly discernible onsite or offsite effects of hydrologic alterations for operation of Callaway Plant Unit 1, and the supply of surface water and groundwater has been sufficient. Operation of Callaway Plant Unit 2 with a closed loop cooling system results in much smaller effects on withdrawals and discharges and correspondingly reduced operational effects than would be expected for an open loop cooling system. The provision of a collector well system provides adequate makeup water for plant cooling, and will have some additional capacity. As explained in Section 2.3.1, since there is a hydraulic connection between groundwater in the Cotter-Jefferson City (CJC) aquifer (the uppermost aquifer of the Cambrian-Ordovician aquifer system), the alluvial aquifer, and the surface water bodies (especially the Missouri River and Auxvasse Creek), it was determined that groundwater modeling should be performed to evaluate the anticipated drawdown and contributing recharge areas in the alluvial and CJC aquifers. Also, evaluations are needed to assess potential impact to well users upgradient from the alluvial aquifer and also to assess the capability and impact of the collector well system during a hypothetical 100-year drought condition. The model simulations suggest that the groundwater capacity required for Callaway Plant Units 1 and 2 can be met by the collector well system (3 collector wells pumping a combined 50,000 gpm (189,300 lpm)) within the parameter constraints reported from the pumping test results by Burns & McDonnell (Burns & McDonnell, 2008a). The model simulations also suggest that the potential impact to the alluvial and CJC aquifers is minimal both under the simulated existing and 100-year drought conditions. The simulated drawdown and contributing recharge areas of the alluvial aquifer at the Callaway Site location are similar to the observed drawdown at the Kansas City Board of Public Utilities well field, which is a comparable collector well system that draws water from the Missouri River Alluvial Aquifer, and estimated contributing recharge areas from a USGS study of well fields in the Kansas City area. There is no anticipated impact to groundwater well users that have been identified in Section as no users have been identified within the estimated contributing recharge areas. During construction of Callaway Plant Unit 2, dewatering foundation excavations will produce localized impacts on the Graydon Chert aquifer. However, the lowered water level would be expected to eventually recover after the dewatering and other subsurface construction activities are completed. As described in Section 2.3.2, a groundwater flow model was utilized to evaluate the potential impact of reduced recharge due to the presence of structures and controlled runoff from the power block area toward the stormwater runoff ponds. This analysis allows for the projection of post-construction groundwater levels below the nuclear island. By reducing recharge from 3 inches per year (7.6 cm per year) to 2 inches per year (5.1 cm per year) across the Callaway Plant Unit 2 area of construction and structures, groundwater elevations are projected to decline by less than 1 ft (0.3 m). Assuming that the highest measured groundwater elevation is 832 ft (253.6 m) msl (mean sea level) (based on measured groundwater elevations in the Graydon Chert aquifer in the Callaway Plant Unit 2 area), the altered maximum groundwater elevation is projected nearer to 831 ft (253.3 m) msl. Dredging in the area immediately in front of the barge slip may be necessary if silt has built up sufficiently to impede barge docking and offload. This is expected to be a one time event and is not anticipated to require maintenance dredging. Consequently, any hydrologic alterations in this area are expected to be local and SMALL. Callaway Plant Unit Rev. 1

13 Water Related Impacts WATER USE IMPACTS Surface Waters Consumptive Use The maximum evaporation loss for the Callaway Plant Unit 2 CWS cooling tower system is estimated to be approximately 19,924 gpm (75,412 lpm). Additionally, makeup water for the ESWS cooling towers is normally supplied from the water treatment plant, which gets water from the Aquifer. Evaporation from the circulated ESWS flow will occur at the cooling towers and will be approximately 940 gpm (3,558 lpm). The Missouri River is the largest sub-basin in the Mississippi River Basin and it covers more than 500,000 sq mi (1,300,000 sq km). As explained in Section 3.4, Callaway Plant Unit 2 will rely on collector wells to supply groundwater and water induced from the Missouri River/Missouri River Alluvial Aquifer for normal makeup water to the CWS and ESWS cooling towers. The collector wells can produce sufficient volume of water even during periods of low river levels and will be able to operate during a 100-year drought elevation of the Missouri River. The volume of water lost to evaporation from the Callaway Plant Unit 2 CWS and ESWS cooling towers is small as compared to the United States Army Corps of Engineers (USACE) controlled flows to the Missouri River (Burns & McDonnell, 2007), and consumptive losses of this magnitude will not be discernible. Drawdown and contributing recharge areas due to water withdrawal from the collector wells were evaluated in Section and summarized in the previous Section There have been no groundwater users identified within the estimated contributing recharge area of the collector well system Non-Consumptive Use Non-consumptive uses of water downstream from the plant are described in Section The major non-consumptive surface water uses in the vicinity of the site are recreation, fishing, and navigation. Recreational activities include swimming, fishing and boating along the Missouri River. Fisheries in the Missouri River are described in Section Navigation on the Missouri River will not be affected by the construction or operation of Callaway Plant Unit 2, water intake from the collector well system, or discharge of the blowdown water to the Missouri River. The primary external impact will be the discharge of cooling tower blowdown water to the Missouri River. The maximum Callaway Plant Unit 2 CWS cooling tower discharge is 9,954 gpm (37,676 lpm). The discharge is designed to provide an acceptable mixing zone for the thermal plume per the State of Missouri regulations for thermal discharges, thus limiting thermal impacts to receiving waters. The mixing zone limitations and related discussion on Callaway Plant Unit 2 mixing zone are presented insection No effect on fishing, navigation, or recreational use of the Missouri River is expected Groundwater Groundwater withdrawals will be used to support operation of Callaway Plant Unit 2 as described in Section 3.3. Water from the Aquifer provides makeup water for plant cooling and onsite deep wells will supply makeup water for power plant operations. As explained previously, it is expected that 15% of the Aquifer water will be derived from upgradient sources of groundwater, while 85% of water will be river water. Groundwater use impacts due to operation of Callaway Plant Unit 2 are explained in more detail in Section and Section Callaway Plant Unit Rev. 1

14 Water Related Impacts WATER QUALITY IMPACTS Water quality data for the surface water and groundwater within the vicinity of the Callaway Plant Unit 2 site are presented in Section In the 2006 Water Quality Report (MDNR, 2006), the Missouri River (where the primary county is Callaway) was declared among potentially impaired classified waters due to habitat degradation. According to this classification, there is some indication that an impairment to some designated use may exist, but the current data or information indicating the impairment do not meet the data requirements set out by Missouri s Section 303(d) Listing Methodology. MDNR will conduct further monitoring on the potentially impaired classified waters in order to determine whether or not these impairments actually exist (MDNR, 2006) Chemical Impacts Callaway Plant Unit 2 utilizes cooling tower-based heat dissipation systems that remove waste heat by allowing water to evaporate to the atmosphere. The water lost to evaporation must be continuously replaced with makeup water. To prevent build up of solids, a small portion of the circulating water stream with elevated levels of solids is drained or blown down. Because cooling towers concentrate solids (minerals and salts) and organics that enter the system in makeup water, cooling tower water chemistry must be maintained with anti-scaling compounds and corrosion inhibitors. Similarly, because conditions in cooling towers are conducive to the growth of fouling bacteria and algae, biocides must be added to the system. This is normally a chlorine- or bromine-based compound, but occasionally hydrogen peroxide or ozone is used. Table lists water treatment systems and chemicals used for Callaway Plant Unit 1. It is anticipated that Callaway Plant Unit 2 will also utilize these water treatment methodologies and chemicals. Section 5.3 specifically deals with the impacts of the cooling system. Limited treatment of raw water to prevent biofouling in the intake structures and makeup water piping may be required. Additional water treatment will take place in the cooling tower basin, and will include the addition of biocides, anti-scaling compounds, and foam dispersants. Sodium hypochlorite is expected to be used to control biological growth in the existing Circulating Water Supply System and will likely be used in the system as well. During the operation of Callaway Plant Unit 2, the existing onsite sanitary wastewater treatment lagoons will manage sanitary wastes. As discussed in Section 3.6, the sewage from Callaway Plant Unit 2 will be combined with the sewage and miscellaneous wastewater (i.e. cafeteria) from Callaway Plant Unit 1 and delivered to the sewage treatment lagoons, which are designed to provide unaided natural biological activity for treating wastewater in compliance with State standards. Effluent from the sewage treatment lagoons is pumped to wetlands adjacent to the sewage lagoons. A detailed description of the wastewater treatment system is provided in Section 3.6. Callaway Plant Unit 1 has a number of NPDES permitted outfalls including the ones draining to the Missouri River or to other areas and receiving streams (MDNR, 2003). It is anticipated that Callaway Plant Unit 2 will take advantage of existing discharge permitted outfalls to the extent possible. The existing permit will need to be reissued prior to the start up of Callaway Plant Unit 2 to include any new permitted outfalls. The facility will continue to monitor all discharges in accordance with State of Missouri issued NPDES permit for the facility. Under this permit, the discharge concentration of Free Available Chlorine (when chlorine is used) in cooling tower blowdown is limited to 0.2 mg/l. The threshold concentration of oil and grease in cooling tower blowdown is specified as 20 mg/l. The discharge from the constructed wetlands is also Callaway Plant Unit Rev. 1

15 Water Related Impacts regulated under the site-specific operating permit. It includes provisions to monitor flow rates, pollutant concentrations, and the biochemical oxygen demand at the point of release. Operation of the CWS and ESWS cooling towers will be based on approximately five (5) and two (2) cycles of concentration, respectively. As a result, levels of solids and organics in cooling tower blowdown will be higher than ambient concentrations in the Missouri River. The final discharge consists of cooling tower blowdown from the CWS cooling towers, the ESWS cooling towers, and site waste streams, including the circulating water treatment systems. Under normal conditions, 5,673 gpm (21,474 lpm) is discharged from Callaway Plant Unit 2 by the existing discharge pipe into the Missouri River; a maximum discharge of 11,929 gpm (45,151 lpm) is anticipated. Considering that the 7 day average low flow in the Missouri River with a recurrence interval of once in 10 years (7Q10) is 16,870 cu ft per second (1,720,000 cu m per hr) or 7,512,000 gpm (28,660,000 lpm) (Burns & McDonnell, 2008b), the maximum discharge stream volume will be approximately 0.16% of the 7Q10 flow in the Missouri River. Therefore, it is expected that the concentrations of solids and chemicals used in cooling tower water treatment will rapidly dilute and approach ambient concentrations in Missouri River after exiting the discharge pipe. Chemical concentrations within effluent streams from the plant will be controlled through engineering and operational/administrative controls in order to meet NPDES requirements. All biocides or chemical additives in the discharge will be among those approved by the U.S. EPA and the State of Missouri as safe for humans and the environment. Based on the above, impacts of the plant discharges to the water quality of the Missouri River will be negligible and are not expected to warrant mitigation Thermal Impacts As noted in Section , discharges from Callaway Plant Unit 2 will be permitted under the NPDES program, which regulates the discharge of pollutants into waters of the state. In this context, waste heat is regarded as a thermal pollutant and is regulated in much the same way as chemical pollutants. Thermal discharges are also regulated under the Revised Statutes of Missouri (RSMo, 2005). Further information describing thermal discharge and the physical impacts associated with operation of Callaway Plant Unit 2 is presented in Section The Callaway Plant discharge line is designed to minimize the potential impact of the thermal plume as it enters the Missouri River. The angle of entry and Tideflex check valve creates rapid mixing of the thermal effluent with ambient river flows. The temperature plume in the Missouri River resulting from discharge of blowdown wastewater was modeled, as is described in Section The results of the thermal plume modeling are presented in the following Section Missouri Mixing Zone Regulations The State of Missouri has established thermal discharge water quality regulations that limit the thermal impact and spatial extent of thermal plumes (RSMo, 2005): The thermal plume may not increase the water temperature in the river by more than 5 F (2.8 C); The thermal plume may not result in river water temperature above 90 F (32.2 C); and Callaway Plant Unit Rev. 1

16 Water Related Impacts The mixing zone is limited to one quarter of the width, cross-sectional area, or volume of flow of the river. The Cornell Mixing Zone Expert System (CORMIX) model was used to model the predicted steady state mixing behavior and plume geometry. The thermal discharge from the Callaway Plant was evaluated at conditions generally considered most stringent: high receiving stream temperature, maximum allowable discharge temperature, maximum discharge rate, and minimum river flow (Burns & McDonnell, 2008b). As discussed in Section 5.3.2, the results of the modeling indicate that the Callaway Site thermal plume achieves water quality standards within a short distance of the outfall. Results of the CORMIX modeling over the range of ambient temperatures modeled show that the length of the mixing zones (distance downstream at which the maximum plume temperature reached the water quality standard) ranged from 7.41 m (24.3 ft) at 85 F (29 C) to m (183.9 ft) at 89 F (31.7 C) as illustrated in Figure Mixing zone widths (maximum distance from the shoreline to the edge of mixing zone) ranged from 6.37 m (20.9 ft) at 85 F (29 C) to m (42.4 ft) at 89 F (31.7 C) (Figure 5.3-1). With a river channel width of m (1,028 ft) at 7Q10, the largest of the mixing zone widths was 4.12% of the width of the river (Burns & McDonnell, 2008b), which is much lower than the State of Missouri limitations for permissible thermal mixing zone areal extent listed above. Thermal impacts to the aquatic communities are therefore expected to be small. Concentrations of water treatment chemicals, such as chlorine and anti-foulants that are added to the cooling system and subsequently discharged in the cooling tower blowdown, will also meet the limitations defined by the Missouri State Operating (NPDES) Permit (MDNR, 2003). Therefore, possible impacts on the aquatic communities are also expected to be small Callaway Plant Unit 1 Discharge The description of the discharge location for Callaway Plant Units 1 and 2 is provided in Section 3.4. The Callaway Plant Unit 2 discharge combines with the discharge from Callaway Plant Unit 1 and flow to the Missouri River through the existing blowdown pipe. The discharge is designed to provide an acceptable mixing zone for the thermal plume per the State of Missouri regulations for thermal discharges Discharge Mixing Zone The discharge outfall for Callaway Plant Unit 2 is located on the north bank of the Missouri River approximately 440 ft (134 m) downstream of the existing intake structure for Callaway Plant Unit 1. The discharge point extends about 100 ft (30 m) into the river through a buried nominal 36 inch (91 cm) discharge pipe with a check valve/diffuser at the end of the line. The centerline elevation of the discharge is ft (150.4 m) above msl. Riprap has been placed around the existing discharge point to resist potential erosion due to the discharge jet from the blowdown pipe Site Surface Water Impacts The existing and new surface water bodies within the Callaway Site are described in Section and Section The potential for these bodies to be impacted by site operations are dependent upon operational conditions related to site safety and spill containment training, a spill pollution prevention plan (SPPP), and a stormwater pollution prevention plan (SWPPP). These plans are addressed in Section 1.3. Callaway Plant Unit Rev. 1

17 Cooling System Impacts Spills or operational debris potentially occurring on outdoor facilities could mix with site precipitation or washing wastewater and be conveyed to downstream impoundments, creeks, and eventually the Missouri River. As proper spill and stormwater pollution prevention plans are implemented and practiced, the majority of polluted runoff can be controlled and prevented from escaping the Callaway Site. Environmental impacts on water quality during construction and operation of Callaway Plant Unit 2 would be minimal. Potential construction effluent impacts on water quality are explained in detail in Section 4.2. Surface water runoff and sedimentation effects will be minimized by implementation of a site safety and spill prevention plan and a stormwater pollution prevention plan. The discharges from the plant will meet all applicable standards described in the site-specific operating permit (MDNR, 2003). With the control of these discharges and the implementation of spill and stormwater pollution prevention plans, the impact on water quality during operation is expected to be SMALL REFERENCES Burns & McDonnell, Report on the Closed-Cycle Cooling and Makeup Water Supply Options for Future Units at the Callaway Nuclear Plant, Fulton, Missouri, March, Burns & McDonnell, 2008a. Phase II Hydrogeologic Investigation Report, Collector Well Siting Study, June, Burns & McDonnell, 2008b. Modeling the Thermal Component of the Wastewater Discharge Plume from Units 1 and 2 of the Callaway Nuclear Power Plant, February MDNR, Missouri State Operating Permit MO , Missouri Department of Natural Resources, Issued October 3, MDNR, Missouri Water Quality Report (Section 305(b) Report), Missouri Department of Natural Resources, Water Protection Program, Published in April 1, RSMo, Revised Statutes of Missouri, 10 CSR , November 30, COOLING SYSTEM IMPACTS This section describes potential impacts from operation of the cooling systems at Callaway Plant Unit 2. The Callaway Plant Unit 2 Circulating Water Supply System (CWS) and Essential Service Water System (ESWS) will be closed-cycle systems. Water is recirculated through cooling towers to remove waste heat. To replace evaporative losses, blowdown, and drift losses, makeup water from the Missouri River/Missouri River Alluvial Aquifer (Aquifer) is supplied to the CWS and to the ESWS during normal and shutdown/cool down conditions following treatment to remove iron in the Water Treatment System. Under post-accident conditions lasting longer than 72 hours, water is supplied to the cooling towers associated with the ESWS from the Essential Service Water Emergency Makeup System (ESWEMS) retention pond. Potential physical and aquatic impacts are associated with water withdrawal by the Collector Well System, heat dissipation to the atmosphere, and elevated temperature of the blowdown as it is returned to the Missouri River. Callaway Plant Unit Rev. 1