ML20140H234
| ML20140H234 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 06/13/1997 |
| From: | NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO) |
| To: | |
| Shared Package | |
| ML20140H238 | List: |
| References | |
| NUDOCS 9706180116 | |
| Download: ML20140H234 (67) | |
Text
{{#Wiki_filter:, Seabrook Station Marine Mammal Protection Act Small Take Permit , Application June 13,1997 NII%,, North F//[ Atlantic The Northeast Utilities System fo0"$0cckosoofgga
i Seabrook Station Marine Mammal Protection Act Small Take Permit Application June 13,1997
\\MIIfo,,
= North p//jjjp Atlantic
_ The Northeast Utilities System
~
1
TABLE OF CONTENTS '
- 1. A Detailed Description of the Specific Activity or Class of Activities That Can Be Expected to Result in Incidental Taking o f Marine Mammals . . . . .. . . . . . . . .. .. . . . . . . . . . . . . .. . . ... . . . . . . .. .. . . ... . . . . . . . . . . . . . . . . . ..Pages 1-4
- 2. The Date(s) and Duration of Such Activity and the Specific Geographical Region Where It Will Occur ...... . . . . . . . . . . . . . . . . . . ..... . ... Pages 5-6
- 3. The Species and Numbers of Marine Manunals Likely to Be .
Found Within the Activity Area. .... . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Pages 7-9
- 4. A Description of the Status, Dist-ibution, and Seasonal Distribution (When Applicable) of the Affected Species or Stocks of Marine Mammals Likely to Be Affected By Such Activiti es . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . Pages 10- 12
- 5. The Type ofIncidental Taking Authorization That is Being Requested (i.e. Takes By Harassment Only; Takes By Harassment, Injury and/or Death) and the Method of Incidental Taking . . .. ... .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . . Page 13
- 6. By Age, Sex, and Reproductive Condition (If Possible), the Number of Marine Mammals (By Species) That May Be Taken By Each Type of Taking Identified in Paragraph (a) (5)
(Section 5) of This Section, and the Number of Times Such Takings By Each Type of Taking Are Likely to Occur...................... . .. . . .....Pages 14-15
- 7. The Anticipated Impact of the Activity Upon the Species or Stock of Marine Mammal .................... . ... ......... ....... ...... ... .... ....... ... . ..... Pages 16-17
- 8. The Anticipated Impact of the Activity on the Availability of the Species or Stocks of Marine Mammals for Subsistence Uses.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..Pagc 18
- 9. The Anticipated Impact of the Activity Upon the Habitat of the Marine Manunal Populations, and the Likelihood of Restoration of the Affected Habitat... .... ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..Pages 19-21
- 10. The Anticipated Impact of the Loss or Modification of the Habitat of the Marine Mammal Populations Involved . ... ..... .... .... ... ... .. .. . .Page 22 1
TABLE OF CONTENTS (continued)
- 11. The Availability and Feadbility (Economic and Technological) of Equipment, Methods, and Manner of Conducting Such Activity or Other Means of Effecting the Least Practicable Adverse Impact Upon the Affected Species or Stocks, Their Habitat, and on Their Availability for Subsistence uses, Paying Particular Attention to Rookeries, Mating Grounds, and Other Areas of Similar Significance.. ..... ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..Pages 23-36
- 12. Where the Proposed Activity Would Take Place In or Near a Traditional Arctic Subsistence Hunting Area and/or Affect the Availability of a Species or Stock cf Mammal for Arctic Subsistence Uses, the Applicant Must Submit Either a Plan eiCooperation or Infomiation that Identifies What Measures Have Been Taken and/or Will Be Taken to Minimize Any Adverse Effects on the Availability of Marine Mammals for S ubsistence Uses . . . . . . . .. . . . . . .. .. . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . ..Page 37
- 13. The Suggested Means of Accomplishing the Necessary Monitoring and Reporting That Will Result in Increased Knowledge of the Species, the Level of Taking or Impacts on Populations of Marine Mammals That Are Expected to Be Present While Conducting Activities and Suggested Means of Minimizing Burdens By Coordinating Such R.eponing Requirements With Other Schemes Already Applicable to Persons Conducting the Activity. Monitoring Plans Should Include a Description of the Survey Techniques That Would Be used to Determine the Movement and Activity of Marine Mammals Near the Activity Site (s) Including Migration and Other Habitat Uses, Such as F eedi ng . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . Pages 3 8-3 9
- 14. Suggested Means of Learning of, Encouraging, and Coordinating Research Opponunities, Plans, and Activities Relating to Reducing Such Incidental Taking and Evaluating Its Effects ... . . . . . . . . . . . . . .. . . .. . . Page 4 0 o
TABLE OF CONTENTS (continued) LITERATURE CITED .... .. .... . ..... . . . . .. . .. .... .. .. . . . .. . .... ..... .... Pages 41 -43 TABLES and FIGURES . ................ ... . ..... ..... ........ .. .. .... .. . . .... . .. Pages T T-9 Table 1 Intact Seal Carcasses Recovered by Month 1993 to 1996 Table 2 Observations of Seal Remains at Seabrook Station by Date Including Necropsy Results Where Available Table 3 Estimated Seal Entrapments by Year Table 4 Preliminary Screening Matrix-Technology or Measure vs. Evaluation Criteria Table 5 Nearfield Monitoring of Seals on Inner Sunks Rocks (1997) Figure 1 Seabrook Station Ocean Cooling Water System Figure 2 Seabrook Station Intake Velocity Cap Figure 3 Seabrook Station Intake Velocity Cap Figure 4 Seabrook Station Circulating Water System Pumphouse Figure 5 Seabrook Station Service Water System Pumphouse Figure 6 Grid Spacing on Existing Intake Velocity Caps Figure 7 Offset Grid Barrier Figure 8 Acoustic Deterrent Device Mooring Option iii
L ENCLOSURE TO LIC-97102/NA-97214 6 9 6 9 e
MARINE MAMMAL PROTECTION ACT SMALL TAKE EXEMPTION PERMIT APPLICATION e
- 1. A detailed description of the specific activity or class of activities that can be expected to result in incidental taking of marine mammals.
Incidental lethal takings of seals have occurred and are expected to continue as a result of the operation of the Seabrook Station cooling water system. Seabrook Station is a single unit 1,150 megawatt nuclear power generating facility located in the New Hampshire coastal town of Seabrook which is approximately 40 miles north of Boston. It is operated by North Atlantic Energy Service Corporation (North Atlantic) as managing agent for the eleven New England utility owners. Seabrook Station began commercial operation in August,1990 and is expected to operate at least until the year 2026, when its operating license expires. The lethal takes occur when seals enter cooling water intake structures which are located in about 60 feet of water about one mile offshore from Hampton Beach, New Hampshire. Some proportion of those seals .. entering the intakes become entrapped as the cooling water is drawn through the intake tunnel to the plant. Contir:uous cooling water flow is necessary for generation of electricity and for the safety of the plant. Design and History of Seabrook Station's Cooling Water System As a base load plant, Seabrook Station normally operates at full power unless shut down for scheduled refuelings and maintenance or for unscheduled forced outages. During nonnal power operations, the cooling water system provides about 469,000 gallons per minute (gpm) of ocean 1 l cooling > ater to the Station. Most of this water, about 448,000 gpm, goes to the mein condenser l
. via the Circulating Water System (CWS) and the three CWS pumps. In the main condenser, the cooling water flows through thousands of condenser tubes and condenses the steam exhausted fro.m the main turbine which is used to generate the plant's electrical output. A smaller amount 1 -
i l of ocean cooling water, about 21,000 gpm, is pumped to various heat exchangers via the Service Water System (SWS) and the four SWS pumps, two of which are normally in operation. The
. SWS is used to provide cooling for other plant machinery and heat exchangers, some of which are related to nuclear safety.
The ocean cooling water is drawn into three offshore intake structures which are located approximately 7,000 feet offshore from Hampton Beach, New Hampshire (Figure 1). The intakes are 110 feet apart and are located in water about 60 feet deep. The intake structures were 4 designed with velocity caps that allow the relatively large mass flow of ocean water to be drawn in at a relatively low speed of about 0.5 feet per second (0.3 knots). The low intake velocities, as well as the horizontal intake currents provided by the velocity cars, minimize the entrapment of marine organisms. The velocity intake caps (Figures 2 and 3) are 30-feet in diameter with seven-foot tall horizontal op nings. The bottom of the horizontal intake cap openings are ten feet above the ocean bottom to minimize the entrapment of bottom fish and lobsters. The top of the intake cap opening is about 40 feet below the ocean surface. The three velocity intake caps draw ocean cooling water inward in a horizontal direction and redirect the flow down via three riser shafts to a single cooling water intake tunnel. Vertical bars are installed every 16 inches around the circumference of the caps to reduce the amount oflarge debris that can enter the intake. The ocean cooling water is delivered from the intakes to Seabrook Station, which is located two miles inland from the coast, via a 17,000 foot long tunnel with a 19 foot inside diameter (Figure
- 1) located in bedrock beneath the ocean and salt marsh floor. Each of the three intake structures is connected to the horizontal intake tunnel by a 110 foot tall riser shaft which has a 9 foot inside
- diameter. The flow rate inside the vertical shaft is approximately six feet per second (3.6 knots).
Once the ocean cooling water reaches the intake tunnel, the flow velocity is about 4 feet per second (2.4 knots) during normal plant power operations. A 16,500 foot long discharge tunnel with a 19 foot inside diameter returns the water to the ocean at a point about 3,000 feet south of the intake location. ( 2 l
The intake tunnel terminates at the plant in a large concrete transition structure. The transition structure is open to the outside air and serves as a surge chamber for the water rising up from the intake tunnel. The intake transition structure is about 95 feet deep and 55 feet by 54 feet across. From the common transition structure, the cooling water is directed to the CWS and the SWS pumphouses (Figures 4 and 5) from which the CWS and SWS pumps deliver cooling water to the main condenser and other plant heat loads. There are three CWS pumps and four SWS pumps located inside their respective pumphouses. Each pumphouse consists of forebay and pump bay areas for each pump. The forebay area contains traveling screens which remove waterbome screen wash debris before it enters the pump suction. The CWS forebay is about 64
, feet deep and 64 feet by 60 feet across. The SWS forebay is about 64 feet deep and 44 feet by 36 feet across.
Waterbome screen wash debri:; is caught on the upstream side of the traveling screens and is carried upward on small shelves attached to the screens as they rotate. As the debris nears the top of screen travel, it is flushed off by high velocity water sprayed from the screen wash l nozzles. The debris falls from the screens into a trash trough which runs the length of both i pumphouses into a collection basket in the Fish Count House. i . During licensing of Seabrook Station in the 1970s, the design and environmental impact potential of the Station's cooling water system received rigorous regulatory review from state and federal agencies, including the Nuclear Regulatory Commission (NRC), Environmental i Protection Agency (EPA), New Hampshire Department of Environmental Services (NHDES) and New Hampshire Fish and Game Department. The conclusion was that the operation of Seabrook Station would not cause significant adverse effects to the aquatic ecosystems or to commercial and recreational fisheries in the area (US NRC 1982). The potential impact to endangered or threatened species such as the shortnose sturgeon (Acipenser brevirostrum), leatherback sea tw11e (Dermochelys coriacea), humpback whale (Megaptera novaeangliae), fin whale (Balaenoptera physalus) and right whale (Eubalaena 3
glacialis) were also considered during the licensing of Seabrook Station and it was concluded that the cooling system operation would not affect these animals (NMFS 1982). It was not - anticipated, however, that seals, which are neither threatened nor endangered, would be impacted by the operation of the Seabrook Station's cooling system and, therefore, the effect on these species was not evaluated at that time. Incidental Takings by Cooling System Intakes Because of the underwater, offshore location, seals have not actually been observed when entering the intake velocity caps. Since the low horizontal flow velocity (0.5 feet per second) into the intakes is unlikely to be enough to draw seals involuntarily inside the intake structure, North Atlantic deduces that the following sequence of events takes place. A seal swims into a velocity intake cap either out of natural curiosity, in search of or in pursuit of prey. Inside the intake velocity cap, the flow rate increases as the seal approaches the center vertical riser shaft that connects to the intake tunnel. This increasing velocity and downward-turning flow causes the seal to be drawn into the riser. The downward current is not something that they normally i encounter in their environment. This situation, combined with the lack oflight and confinement ; inside the velocity cap and riser, disorients the seal and prevents an effective escape response, I especially for young-of-the-year seals. As a result, the seal is unable to exit, drowns and its l carcass is subsequently drawn into a pumphouse forebays. During full power operations, Seabrook Station operates with all CWS and two SWS pumps in operation. For an object traveling with the current under these conditions, the minimum transit time from the offshore intake structures to the forebay is approximately 80 minutes. Transit time is longer if fewer pumps are operating. A seal entrapped in the intake would not be able to smvive an 80 minute or longer transit to the forebays. l l l l 4
- 2. The date(s) and duration of such activity and the specific geographical region where it will occur.
Seabrook Station is a baseload electric generating facility which means that it normally operates continuously at full power. The only routinely scheduled shutdowns are the refueling and maintenance outages which currently occur about every 18 months. The length of Seabrook Station's four refueling and maintenance outages that have been completed to date have varied from 37 to 114 days. Even during shutdowns, however, at least one of the three Circulatmg Water System Pumps and one of the four Service Water Pumps are usually in operation, l drawing water in through the offshore intake structures. Operation of the Station in this manner is expected to continue at least until Seabrook Station's Operating License, issued by the Nuclear Regulatory Conunission, expires in 2026. A.c shown in Figure 1, the location of the three ocean water intake structures where the takes cccur are approximately 7,000 feet offshore of Hampton Beach, New Hampshire.
Background
Seal takes were first observed and reported at Seabrook Station in October,1993. This was eight years after cooling water first began being pumped through the offshore intake structures in 1985 and more than three years after Seabrook Station began commercial operations in August,1990. The cooling system operated intermittently and at reduced flow rates during the period 1985 to l 1990. Although seal takes are possible year-round, there appears to be a seasonal relationship. Table 1 provides the distribution by month of the observations of the 18 seal carcasses that have been j
- discovered in an intact con.iidon. Because they were intact when observed, it is reasonable to assume that the seals were e.v. rapped close to the date of observation. On this basis, Table 1 indicates that most entrapmems occur from August through October.
5
l In some instances, the intact seal carcasses were washed from the traveling screens and observed in screen wash debris where they were easily recovered. At other times, the intact seal carcasses were discovered floating in the CWS and SWS forebays. Although recovery is difficult because 1 the water surface in each forebay is about 15 feet below the working floor of the Pumphouse l l Building with no direct access by personnel, fourteen of the 18 intact seal carcasses were ! l recovered. They were then transported to the New England Aquarium, the Marine Mammal Stranding Network letter holder for the region, where necropsies were performed. In addition to the intact carcasses, skull fragments and other bones have been recovered from screen wash debris. Whenever possible, recovered skulls or skull fragments were also analyzed by the New l England Aquarium. Table 2 is a listing of observations of seal remains by date of first ! l observation. It describes the extent of remains observed, the location where the seal remains were first observed, and necropsy results, if available. When only seal skulls and bones were observed, the date of entrapment could have been a significant length of time before the observation date. Because observations sometimes consist of only partial remains, it is not always possible to determine if the remains come from one or more seals. Precise quantification of the total number of entrapments is therefore difficult. The estimate of the total number of seals entrapped to date is between 27 and 33. This number was determined from the seal remains recovered, including intact carcasses, skulls, partial skulls, bones, hide and internals. A summary of the estimated number of seals taken by year is shown in Table 3. Based on this past history of seal takes and the growing seal population in the area, North Atlantic expects that seal takes will continue, especially from August through October, throughout the plant's operating life. 6
1
- 3. The species and numbers of marine mammals likely to be found within the activity area.
The marine mammal species most likely to be affected by the operation of Seabrook Station is ; harbor seal (Phoca virulina). To a lesser degree, gray seal (Halichoerus grypus), harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata) are also expected to be affected. Each of these species occurs in the area of Seabrook Station. Harbor, harp and hooded seals have been identified from previous takes (see Section 2). Indications are that the populations of all four seal species have been increasing in the Gulf of Maine (Kenney and Gilbert 1994; Blaylock et al.1995) since the passage of the Marine Mammal Protection Act (MMPA) in 1972. This is particularly true for harbor and gray seals, the two most common species in the Gulf of Maine. Harbor seals have increased nearly five-fold (Blaylock et al.1995), while the gray seal population has also increased greatly along the New England coast (Gilbert pers. comm. in Blaylock et al.1995). Harbor arJ gray seals have also been dispersing southward from Maine rookeries (Paton 1988; Payne and Schneider 1984). Harp and hooded seal populations may also be increasing in U.S. waters as evidenced by increased sightings and strandings (Blaylock et al.1995).
~
Harbor seal population censuses have been made for the coast of Maine in 1981,1982,1986 and 1993 (Kenney and Gilbert 1994). Estimates were based on aerial surveys taken along the Maine coast during the May to June pupping season. This technique was used because seals regularly 7
retum to land (haul-out) to give birth, nurse, thermoregulate and rest (Kenney and Gilbert 1994). The largest number of seals at haul-out sites have been observed during the pupping season (Sullivan 1980; Brown and Mate 1983). Population estimates from these surveys represent the minimum population size because the census is not corrected for seals that may be in the water at the time of counting (Kenney and Gilbert 1994). Since adult and juvenile males typically only haulout about once every six low tides, the total population in the surveyed areas may be j underestimated by about 30 to 40% (Gilbert pers comm.). In addition, not all potential haul-out locations are surveyed, particularly sites that may be upstream in tidal rivers (Gilbert pers. comm.). The annual changes in these minimum counts, however, provide a relative index of populadon growth. According to the 1993 census, the minimum uncorrected population estimate of harbor seals along the Maine coast at that time was 28,810 (Blaylock et al.1995). This represents an annual rate ofincrease of 8.7% along the Maine coast between 1981 and 1993. ; I Most of the seals taken by the operation of Seabrook Station were harbor seals and over 80% of the harbor seals, for which ages have been estimated, were young-of-the-year (see section 6). Although'no local census data specific to New Hampshire waters is available, the adjacent Southern Maine coast (Pemaquid Point to the Isles of Shoals) is on the southern edge of the breeding range for harbor seals. The data indicate that pups make up a greater percentage of the population in the Downeast (Cobscook Bay to Schoodic Point) and Middle (Schoodic Point to
~
Pemaquid Point) coast regions (Kenney and Gilbert 1994). In the Southern coast region, only
. 8.3% of the seals counted in the 1993 survey were pups. The furthest south a newborn pup was 8
4 observed was on Shag Rock in the Isles of Shoals, about 10 miles nonh of the Seabrook Station intakes. l l The gray seal range is centered in the Gulf of St. Lawrence and is distributed primarily in eastern j A Canadian waters (Blaylock et al.1995). Small numbers of animals including pups, however, .
)
have been observed on several isolated islands along the Maine coast and in Nantucket-Vineyard l I Sound, Massachusetts (Katona et al.1993; Rough 1995). Although range-wide gray seal I population estimates are not known, the estimate for individuals that are one year or older rose from between 100,000 and 130,000 animals in the North Atlantic in 1986 (Stobo and Zwanenburg 1990) to 143,000 animals in 1993 (Mohn and Bowen 1994). Gray seals were occasionally observed in the summers on the coast of Maine during the mid 1970s and the 1980s but have become more common in the 1990s. The population in Maine waters has increased from about 30 in the early 1980's (Gilbert pers. comm. in Blaylock et al.1995) to between 500-1000 animals in 1993 (Kenney and Gilbert 1994). The minimum uncorrected population estimate for all US waters is about 2,000 seals in 1994 (Blaylock et al.1995). No estimate exists for the number of harp or hooded seals in US waters, as these species are found primarily in nonhern Canadian waters. The population of both species appears to be growing in Canadian waters (Blaylock et al.1995). The total population of harp seals in Canada
~
was estimated at approximately 3 million seals (Shelton et al.1992) and the average annual
. growth rate was estimated as 7% (Stenson 1993). The total estimated population of hooded seals in Canada was about 400,000 to 450,000 seals (Stenson 1993) and the population appears to be increasing.
9
- 4. A description of the status, distribution, and seasonal distribution (when applicable) of the affected species or stocks of marine mammals likely to be affected by such activities.
All four species of seals likely to be affected by the operation of Seabrook Station cooling water system are protected under the Marine Mammal Protection Act. None are afforded threatened or endangered status under the Endangered Species Act, and none are considered a " strategic stock" (Barlow et al.1995). Strategic stocks are stocks where the estimated incidental fisheries mortality is greater than the potential biological removal (see Section 7). The harbor seal ranges from the eastern Canadian Arctic and Greenland to as far south as North ; l Carolina (Hall and Kelson 1959). There is believed to be a single stock in the western North Atlantic (Blaylock et al.1995). All harbor seals found in the US waters of the Gulf of Maine, therefore, belong to this one stock. Strandings have been reported as far south as Georgia (unpublished data cited in Blaylock et al.1995). Harbor seals undergo seasonal movements with a general southern movement from Canada and northern New England toward southem New England occurring in fall and winter although some part of the population is resident year round (Rosenfeld et al.1988; Whitman and Payne 1990). The majority of the seals completing this southem movement appear to be juveniles (Whitman and Payne 1990). A northward movement from southem New England begins prior to the mid-May through June pupping season (Schneider and Payne 1983). Weaning takes place at four to six weeks of age (Riedman 1990). 10
I The entrapment of harbor seals at Seabrook Station is consistent with the described movements of harbor seals. The majority ofintact, identifiable harbor seals were entrapped from August to October (see Table 1), and appeared to have been recently weaned young-of-the-year. Gray seals range in the western North Atlantic from Labrador to as far south as New Jersey (Hall and Kelson 1959) and there is believed to be one stock in the US waters of the Gulf of Maine (Blaylock et al.1995). The center of abundance is in the Gulf of St. Lawrence (Blaylock et al. 1995), and a breeding population exists on Muskegut Island off Nantucket (Paton 1988). Gray seals can be found in the Gulf of Maine in the summer, sometimes intermixed with harbor seals, but most mature individuals return to Canadian waters to breed in the winter (Katona et al. 1975). There has been no confirmed entrapment of gray seals at Seabrook Station, but the potential for a taking exists. Harp seals are found primarily in the North Atlantic and Arctic Oceans, and a few individuals l may range' as far south as New Jersey (Blaylock et al.1995). In the North Atlantic, harp seals j l breed in mid-February and April off the coast of Newfoundland and Labrador, and near the l Magdalen Islands in the Gulf of St. Lawrence. In late September, after a summer of feeding in far northern waters, harp seals move southward. At this tinie, they may enter the US waters of the Gulf of Maine. The partial skull of a harp seal was recovered from screenwash debris in December 1995. This seal was probably entrapped earlier in the fall during the southem dispersal that occurs in the late-summer through fall. Fragments of a second harp seal skull were 11
E , recovered from screen wash debris in April of 1997. These fragments came from a harp seal that
- i. was probably entrapped in late 1996. The population of harp seals appears to be increasing in
! Canadian waters. The population in US waters is also increasing as evidenced by an increase in
~
- the number of strandings and fishery bycatch (Blaylock et al.1995).
I a i Hooded seals are found in the North Atlantic and Arctic Oceans, primarily in Canada, and are , l i highly migratory (Blaylock et al.1995). A few individuals have been reported as far south as l Puerto Rico. Sightings in US waters have occurred from Maine to Florida, and appear to be 4
- increasing in conjunction with the overall population increase. In the western North Atlantic, breeding occurs in February on sea ice off the coast of Newfoundland and Labrador and at a second area in the Gulf of St. Lawrence (Blaylock et al.1995). After breeding, adults migrate to the Denmark Strait to molt between June and August. After molting, hooded seals disperse widely and this is wl en sightings occur outside of their normal range. The skull of a hooded seal was recovered from screenwash debris in May of 1995, and probably was from an entrapment event earlier in the year. This occurrence it eady 1995 was probably part of the fall through winter dispersal.
i I l 12
- 5. The type of incidental taking authorization that is being requested (i.e. takes by harassment only; takes by harassment, injury and/or death) and the method of
- incidental taking. The type of incidental taking being requested in this application is an incidental lethal taking caused by entrapment of the seals in the Seabrook Station cooling water system intakes as described in Section 1. I e 13
- 6. By age, sex, and reproductive condition (if possible), the number of marine mammals (by species) that may be taken by each type of taking identified in paragraph (a) (5)
(Section 5) of this section, and the number of times such takings by each type of taking are likely to occur. ~ i Incidental lethal takings of seals are anticipated to occur as a result of the operation of the ) Seabrook Station cooling water system. Seabrook Station is expected to operate at least until the expiration ofits Operating License in 2026. I Based on seal entrapments at Seabrook Station, it is anticipated that most takings are likely to be of young-of-the-year harbor seals with less frequent takes of gray, harp and hooded seals. Harbor Seals l The anticipated number of lethal takes of harbor seals may increase as a result of the increase in the harbor seal population in the area near Seabrook Station's cooling water system intakes ! structures. J l Of the 27-33 seals entrapped from 1993 to the date of this submittal,23 have been identified by species. Twenty of these 23 have been confirmed to be harbor seals. Of the twelve whose ages were estimated by the New England Aquarium, ten were young-of-the-year harbor seals equally divided between males and females. Harn Seals i
- The two harp seals entrapped by Seabrook Station were identified by partial skull remains.
Neither sex nor age was able to be ascertained. There has been a dramatic increase in the number ! of harp seal strandings in the Gulf of Maine in recent years reflecting a shift in their distribution (Mooney-Seus and Stone 1995). It is anticipated that future harp seal entrapments will occur but 14
1
. l will still be much less frequent than entrapments of harbor seals since Seabrook Station is in the I
southerly part of the harp seal's extended range. Hooded Spals Although a positive identification could not be made, the New England Aquarium stated that the remains of one skull were probably from a hooded seal of unknown age and sex. As with harp seals, the strandings of hooded seals has increased dramatically in recent years although they are , still much less frequent than that of harp seals (Mooney-Seus and Stone 1995). It is anticipated, therefore, that future hooded seal entrapments may occur but would be relatively rare events since Seabrook Station is in the southerly part of their extended range. , i 1 Gray Seals No gray seal remains have been identified to-date. Since there are significant populations of gray seals in the area and since these populations are increasing, it is anticipated that gray seals could become entrapped in the Seabrook Station cooling water intake structures in the future. I 4 9 f l 15
. - , - - ~ , a a - - , - - = . ,-, .,
1 i
- 7. The anticipated impact of the activity upon the species or stock of marine mammal.
The seal species taken at Seabrook Station include harbor seal, harp seal, and hooded seal (see
. Section 6). In addition, the gray seal has the potential to be taken at the Station. There is evidence that the populations of all these species are increasing and their ranges are extending i further south (Blaylock et al.1995). The continued operation of Seabrook Station is anticipated to have a negligible effect on the population or stocks of these seal species as discussed below.
l The Marine Mammal Protection Act as amended in 1994 requires the National Marine Fisheries < l l Service (NMFS) to produce stock assessment reports for all marine mammal stocks in waters , l within the US Exclusive Economic Zone. As part of that assessment, NMFS is required to ' estimate the potential biological removal (PBR) for each stock of each species. The PBR is the maximum number of marine animals, not including natural mortalities, that may be removed from a marine mammal stock while allowing the stock to reach or maintain its optimum sustainable population (OSP). If the number of animals removed from the stock exceeds the PBR, the stock is declared " strategic", and additional conservation measures are initiated (Barlow et al.1995). If the number removed is less than PBR, the stock is considered to be within the range of OSP. l The determinations of PBR were published by NMFS in Blaylock et al. (1995). For harbor seals, the PBR was determined to be 1,729 seals. The total annual take estimated from sources other l than Seabrook Station was 476 harbor seals (Blaylock et al.1995; p.113). The maximum estimated annual mortality at Seabrook Station was 17 in 1996 which is less than 4% of the total i 16
take and 1% of the PBR. Therefore, the additional take from this source does not change the status of the stock or impact the stock of harbor seals significantly. Although no identified takes of gray seals have occurred at Seabrook Station, the expanding population in the area increases the potential for future entrapment. The PBR for gray seals was determined to be 122 individuals (Blaylock et al.1993). The total annual take from other sources - was estimated at 4.5 gray seals. Therefore, this incidental take, combined with any future take from Seabrook Station, would be insignificant. No PBR has been calculated for harp or hooded seals because data are not available to estimate the stocks in US waters. However, because they must be considered a part of the Canadian stocks (where reproduction occurs), and because numbers are increasing in Canada, the incidental takes at Seabrook Station are insignificant. The population of both species appear to be expanding seasonally southward into US waters. Prior to the late 1980s, few were recovered in the Gulf of Maine. Since then, strandings have increased by an order of magnitude (Mooney-Seus and Stone 1995). 9 17
- 8. The anticipated impact of the activity on the availability of the species or stocks of marine mammals for subsistence uses.
There are no subsistence uses of seals in the US Atlantic waters (E. Hutchins, NMFS, pers, conun.). l i e i 18
i l
- 9. The anticipated impact of the activity upon the habitat of the marine mammal populations, and the likelihood of restoration of the affected habitat.
The continued operation of Seabrook Station is anticipated to have negligible impact on the habitat of seals. The anticipated impact of Seabrook Station including its cooling water system on the environment was thoroughly evaluated by state and federal agencies in accordance with the requirements of the National Environmental Policy Act during the review of the construction permit application. The operation of the cooling water system has been through the authorization of, and in accordance with, the National Pollutant Discharge Elimination System (NPDES) permit issued by the Environmental Protection Agency. There are no Seabrook Station activities planned for the offshore area other than the continued l operation of the cooling water system. Thus, potential seal habitat impacts are limited to those i J associated with the physical presence of the intake and discharge structures and the effects of operation of the cooling water system. These are considered below. The operation of Seabrook Station has not influenced the entrapment of seals by altering the ! l balanced indigenous populations (BIP) of marine biota in either the discharge or intake areas. There have been no detectable impacts to the BIP due to the discharge of heated effluent (NAI 1996). There is no evidence that the distribution of fish, an important food source for seals, has
- been altered at either the discharge or intake areas by the operation of Seabrook Station.
Similarly, the distribution and abundance of phytoplankton, zooplankton, ichthyoplankton, and 1 19 l
t the physicochemical environment has not been significantly affected by the operation of the ! Station (NAI 1996). The discharge of heated effluent has had no apparent effect on seal habitat. Typically, the , i monthly average increase in surface water temperatures at the discharge is less than 3* F over an i area ofless than 32 acres (Padmanabhan and Hecker 1991). This heated discharge water does not extend to the intake structures (Padmanabhan and Hecker 1991) and therefore does not modify seal behavior near the intakes. The plant has been in compliance with NPDES permit (NAI 1996). After the plant reaches the end of its anticipated operating life in 2026 when its current operating license expires, or later if an extension is received, it will be decommissioned and the intakes capped. At that point, there will be no further discharge of heated effluent. 1 The operation of Seabrook Station requires the presence of intake structures to provide cooling water, which could be considered a habitat modification. Three intake structures are located in about 60 feet of water and rise approximately 17 feet into the water column (see Section I for further details). These structures provide the entry point for seals to the cooling water system of the plant. The seals that become entrapped appear to be primarily naive young-of-the-year seals which are not able to swim back out either due to disorientation, the increased flow velocity in the riser shafts, the confinement of the structure, the lack of light in the intake or a combination .
^
I of these factors. 1 In summary, the discharge structures have had no discemible impact upon the habitat of seals. The only discernible impact that the intake structures have had on seals is the incidental takes of 20
l l individual seals. With respect to restoration, both the intake and discharge structures will be I capped as part of ultimate plant decommissioning so that seals, fish and divers cannot enter. l as 6 4 i 1 1 i J I 1 I a i l l i l 1 i 21 se y -m- w - y --%. e- v- *,n,, -~r-6 --em.--+re---,
i l l
- 10. The anticipated impact of the loss or modification of the habitat on the marine mammal populations involved.
The continued operation of Seabrook Station and its cooling water system has had, and is anticipated to continue to have, a negligible impact on the habitat of seals as discussed below. There have been no demonstrated significant changes in the physicochemical, phytoplankton, zooplankton, and fish communities in the vicinity of the discharge (NAI 1996). Therefore, it is unlikely that there have been any changes in the availability of prey items of seals or that their behavior has been modified. As discussed in Section 9, the continued presence of the intake structures does not entail any discernible modification of the habitat of seals, although the intake structures do provide the entrance point to the cooling water system where seal mortality has occurred. Seals, at least adults, do not appear to be involuntarily swept into the intakes. The water current velocity of 0.5 ft/sec at the entrance to the intakes is less than the 16 ft/sec measured swimming speed of adult i seals (Bonner 1990 p.9). In addition, the growth of organisms on the intake structures does not appear to be encouraging the development of a significant fouling community that would attract seals. The intake structures are encased in a nickel-copper metal alloy designed to minimize growth by fouling organisms. The intakes are cleaned periodically by divers in accordance with the NPDES permit for the Station. Fish entrapment at Seabrook Station is less than that found at comparable coastal power plants (NAI 1996). 22
1 l o \ 11.The availability and feasibility (economic and technological) of equipment, methods, l and manner of conducting such activity or other means of effecting the least practicable l adverse impact upon the affected species or stocks, their habitat, and on their availability for subsistence uses, paying particular attention to rookeries, mating i grounds, and other areas of similar significance. l North Atlantic is exploring options to prevent seal entrapment and will continue to pursue alternative means to deter seals from entering the Seabrook Station cooling water intake. Through the time of this permit application, North Atlantic has reviewed numerous possibilities, and evaluated each against a set of acceptance criteria. A number of alternatives initially I considered have been eliminated by this process. Two options have been determined to be potentially feasible and are being pursued in more detail. These are: 1) design and installation of a physical barrier to prevent the entry of seals; and,2) use of an acoustic deterrent desice (ADD) to deter seals from the area of the intake structures. Additional efforts are necessary to determine the feasibility and cost ofimplementing a deterrent system. Efforts to date and plans to evaluate potential alternatives are described below. 23
I
11.1 INTRODUCTION
To prevent seals from entering the intde structures and possibly being entrapped by the cooling water system would require either a physical barrier or some means of discouraging their presence in the vicinity. As described in Section 7 of this permit application there are no adverse impacts from the plant to seal populations or stocks, which continue to grow (Blaylock et al., 1995). There is also no impact to seal habitat other than the direct taking itself, nor is there subsistence use in this region. Most seals which are affected are young-of-the-year (see Section 6). As there is either no or very limited apparent pupping in the area, it is assumed that seals that n ay be taken will be from among those migrating through the area, particularly on their fall southward migration from Canada and Maine to the southern Gulf of Maine and Long Island (Katona et al.1993). l l l l With no significant projected impacts from Seabrook Station seal takes to the population or any sensitive areas, the primary purpose for any proposed actions will be to prevent the loss of those individual seals that would otherwise be removed from the population by entrapment in the intake tunnel through the normal operation of Seabrook Station. The effort to determine the best method of reducing or preventing seals from being entrapped by the cooling water system, has entailed: 1) development of a list of possible measures, 2) a
- preliminary screening of those measures, and, 3) a more detailed evaluation of the most promising options.
24
1 Tbc remainder of this section presents the preliminary screening process, criteria, and results , (Subsection 11.2); a brief discussion of the alternatives eliminated from further consideration (Subsection 11.3); an evaluation of the altematives retained for further analysis (Subsection 11.4); and, North Atlantic's plan for completing the feasibility study (Subsection 11.5). l I 11.2 PRELIMINARY SCREENING OF ALTERNATIVES North Atlantic developed a range of possible technologies or measures to minimize seal takings at Seabrook Station. North Atlantic then screened these technologies or measures using a set of acceptance criteria. Technologies or measures passing the initial screening process were carried forward if they either met all screening criteria or hed promise but required further information to complete the evaluation. l l l 11.2.1. Criteria and process Possible alternative means of minimizing the incidental taking of seals during operation of the cooling water system were developed through a literature search, internal discussions, and contacts with a number of individuals, including: biologists with expertise in the area of seal behavior and population dynamics; individuals familiar with tecimiques or technologies used to deter seal predation in aquaculture; oceanographers and ocean engineers with expertise and familiarity with coastal ocean dynamics and offshore structural design and maintenance; and, others with specialized knowledge that might be applicable. l 25
l Alternatives were screened based on the following criteria: o Effective (A) Will minimize or eliminate seal entrapment into the intake. o Proven in some manner or The technology has been utilized in some application l application (B) (if unlike the proposed use) and shown to be feasible. l i o Within nuclear safety Does not cause an alteration or impact the operation l constraints (C) in a manner that would compromise safety of the 1 operation. . o Within operational and Does not require major reconsideration or alteration licensing constraints (D) of the operations for which the plant has .been designed and licensed. o Implementable (E) The technology can be implemented within operational, safety and licensing constraints of the facility. o Economically practicable (F) For preliminary screening, defined as less than the cost to redesign and replace the current velocity cap structures. o Federal and state agency Acceptable to directly and indirectly involved federal acceptability (G) and state agencies, including US NMFS, US . Environmental Protection Agency, NH Department of Environmental Services, NH Fish & Game ! Department, and others as appropriate. I o Minimal effects on non- Does not create effects on other species or habitats target species (H) which are more significant than the negligible impact to seal populations of the present operation.
- j l
l l l 26
11.2.2. Evaluation ~ Many initially-proposed alternatives were eliminated from further consideration on the basis of significant failures versus the evaluation criteria. Some required additional information gathering or analyses before they were either eliminated or carried forward. Others, which have not been l eliminated from further consideration at this time will, require additional information and analyses to determine whether they should be carried further into the process. The technologies or measures considered are listed in Table 4 along with a synopsis of their assessment versus the evaluation criteria. 11.3 ALTERNATIVES ELIMINATED FROM CONSIDERATION I l The following eight categories of potential attematives were considered but eliminated from further consideration, most on the basis either that they are not presently known to be effective or 1 that they are not feasible (Table 4). I Intake modification to provide visual or behavioral deterrent. Redesign of the intake to ! provide a visual or behavioral deterrent was considered and eliminated because there were no designs that could be identified that would cause seals to avoid the intake structure or avoid
. entering the structure.
27
Predator models. Use oflife-size predator models, such as of killer whales, was considered and eliminated from serious consideration at this time because the effectiveness of this approach to I deter harbor seals has not been conclusively demonstrated (NMFS 1995; Reeves et al.1996). Though there might be initial avoidance, seals tend to leam to ignore non-reinforced stimuli over time (Reeves et al.1996). Research or application developments in the area of predator model - l 1 deterrents will continue to be monitored while other altematives are being evaluated. 3 1 Predator sounds projection. Use of predator sounds, such as of killer whale vocalizations, , 1 alone or in conjunction with life-size predator models, was considered and also eliminated from further consideration at this time. Lack of proven effectiveness and considerations of habituation I l apply for sounds as well as models (Reeves et al.1996; NMFS 1997). Moored, buoyed net barrier. Use of a suspended net was considered and eliminated from further consideration. Such a net system would be moored by multiple anchors to the seafloor and the upper end suspended by multiple buoys at the surface. The net system would either , i surround the entire area of the three velocity caps, or surround each one independently. Further assessment of this alternative has failed to identify situations of successful deployment of 1 surface-to-bottom barriers over extended time periods. Significant deployment issues include: response of the net barrier to fouling by debris, especially during storms; maintenance of l mooring systems and buoyed surface of the nets during storm events which are especially
. prevalent during the months of primary concern for seal entrapment (late summer and fall); and difficulty in assuring that nets will remain deployed completely from surface to bottom, 28
preventing entrance inside the net structure. Additionally, should seals or other mobile marine animals get inside the net, it might be difficult for them to relocate the point of entry. Their e inability to exit the net enclosure would make them more prone to entering the intake structure. In addition, it is possible that seals would traverse the top of the net, defeating the barrier's effectiveness. Rigid cage structure surrounding intakes. Use of a rigid cage structure to fully enclose the area of the three intakes together or individually was considered and eliminated from further consideration. Requirements for such a system would include: grid spacing small enough to prevent seal pups from entering; either vertical components that went to the water surface at the highest predicted tide (including storm surge) or a horizontal " cap" across the entire structure; a method to secure the structure to the seafloor by pilings or other permanent means; and a barrier grid that would have no openings at any joints, especially at the interface with the seafloor. Significant issues include: no known proven technology; vertical walls extending to the highest
. anticipated water levels would be dangerous to navigation; fouling and/or clogging could pose dangers to the operation of the cooling water system; fouling and/or clogging could cause high maintenance costs and additional risk to workers for cleaning and maintenance; and potential safety and operational issues associated with the structural integrity for a horizontal cap, especially under conditions of heavy loading by debris or during storms.
. Bubble curtain. Use of a " bubble curtain" was considered and eliminated from further consideration. In a bubble curtain, air would be pumped through a pipe that would surround the 29
intake structures and air bubbles released through holes in Se pipe, thus creating a vertical
" wall" of bubbles. There is no demonstrated use of this technology to deter marine mammals (Tillapaugh et al. In press). Additionally, the fact that the intakes draw currents into the structure would deflect any bubble curtain inward, and, storm surge and current patterns would make it unlikely that a steady " barrier" would be maintained.
I Translocation of seals. This alternative is unfeasible and will not be considered further. Translocation of seals could only be effective if the specific seals could be identified. Seals i impacted are thought to be young-of-the-year orjuveniles that are migrating. Other beh AVIOral-based deterrents. No specific behavioral-based deterrents have been i identified. Considerations have included whether seals might respond to color differences or whether there might be some use of a maze response to deter them from entering the intake structure. Should any alternatives be identified which would deter seals from the intake i l structures by eliciting a behavioral-based response, they will be considered in the future. l l l 11.4 ALTERNATIVES RETAINED FOR FURTHER ANALYSIS Two alternatives have been retained for further consideration: 1) retrofit of a barrier to the
~
existing velocity cap that utilizes either close-spaced one-directional bars or square-mesh grid l l directly applied to the current structure, or an extension on the existing intake structure that ! would include close-spaced bars or square grid; and 2) installation and operation of an Acoustic 30
Deterrent Device (ADD) system that would deter seals from the intake by broadcast of underwater sound. Further analyses will be required to determine the economic and technological feasibility of each of these alternatives. ; i i Grid barrier on existing velocity cap structure. Addition of small grid spacing within the ! existing velocity cap structures was considered and retained for more detailed analysis (Figure 6). Small spacing could be the most reliable means of excluding seals. If grid spacing small ! enough to prevent pups from entering the intakes presents operational problems to the plant,
' larger spacing will be required. Larger spacing grids that physically exclude older seals may still present a behavioral barrier to smaller seals. Issues that will be further addressed include: l i
t
. What size grid spacing will keep all or most seals from entering the intake structure?
- Will grid spacing meet plant operational, safety, and NPDES Permit requirements? f
\
e Will smaller grid spacing cause increased incurrent flow velocities that may have a ! detrimental impact on fish impingement? l e Will smaller grid spacing increase the potential for biofouling of the grid and ; l J corresponding impacts on current velocities, fish attraction (" reef effect") and attraction to seals? i e Will smaller grid spacing increase the potential for blockage by debris or organisms
- to levels detrimental to the plant's operation?
l
-
- What will be the maintenance requirements associated with smaller grid spacing-frequency, manpower, risks, costs? ,
l 31
l
. What will be the overall costs associated with selecting, designing, installing, operating and maintaining smaller grid spacing?
e If the size does not physically exclude all possible seals from entering the intake, will j this barrier design be acceptable? !
. How will success be monitored? !
Specific actions to address these questions are outlined in permit application subsection 11.4 l below. Grid barrier on structural offset to existing velocity cap. Grid barriers deployed directly on < l the existing velocity cap barriers may not be feasible due to plant safety, operational I considerations, unfavorable alterations to intake flow velocities, or maintenance requirements. i An alternative design that would increase the surface area of the gridded barrier may provide a ) deterrent to seals while reducing some of the potential disadvantages (see Figure 7). This option has been considered and retained for more detailed analysis. Most of the issues identified for a grid barrier on the existing structure must also be addressed for this option. In addition, structural integrity of the design as well as operational considerations may be significant considerations for a retrofit design offset from the present structures. Acoustic Deterrent Devices (ADDS). Underwater, sound-emitting devices have been in
]
experimentation or use since the early 1980s , especially to deter seals from salmon aquaculture net pens in coastal waters (Mate and Harvey 1987; Morris 1996; NMFS 1996). ADDS have also l 4 i 32 ! 1
recently been found to be effective for minimizing cetacean bycatch in offshore floating gill net fisheries (NMFS 1996b), though this application is still under study, and are in use to deter fish from power plant intake structures and other sensitive areas. Of direct application to Seabrook Station, in particular, is a system that was developed and tested beginning in 1993, the AIRMAR "dB plus" system. As one of a new generation of more powerful ADDS (Norberg and Bain 1994), it transmits at a frequency and sound level that is painful to harbor seals at approximately 150 feet from system sound projectors. The system is in widespread use at salmon farms in Maine, and in British Columbia and New Brunswick, Canada. Over 200 systems have been sold between 1994 and 1997, indicating their perceived effectiveness for the purpose. The proven application of ADDS to deter seals from salmon net pens, for which a strong motivation for seals exists, suggests the potential effectiveness of ADDS for deterrence at Seabrook Station, an application in which there is relatively little motivation for seal entry. On this basis, ADDS are retained for further consideration. Of a number of alternatives to house an ADD systern for the Seabrook Station intake, a moored buoy system is presently being given the most detailed evaluation (see Figure 8). Issues for potential ADD deployment are significant, and include: Design issues
- What strength and frequency of the projected sound will be an etTective deterrent for this application and will the identified effective strength or frequency create a health or safety risk for divers in the area ofinstallation?
l 33 l
)
i 1 e What are the electrical requirements for this operational mode and how should electric power be provided to operate the system at this offshore location?
. What platform (i.e., tower, spar buoy, spherical, surface-following buoy) will best maintain the surface components of the system, including the control unit, batteries, and battery-charging system (wind power, solar, or diesel generator) under conditions that include both normal tides, winds and waves as well as storm conditions?
e What system will be best to effectively monitor that the ADD system is operating as intended? and, ; e What system will minimize operations and maintenance costs and risks to offshore servicing personnel? l l Environmental and permit issues l
. Is there potential harm to seal pups or cetaceans via damage to the middle or inner !
car?
. Are there potential effects to other marine organisms, such as avoidance by species of l 1
fish?
. Will there be " habitat exclusion" for any cetaceans (especially harbor porpoise) and, ;
l if so, what would be the impacts?
. What are the permitting or notification requirements for navigation purposes? . e Should a zone of exclusion be established for navigational purposes, and, if so, how l
l ! should the area be demarcated? l l l 34
_ _ _ . . . . - _ _ _ _ _ _ _- ~ __ _ . . _ _ _ . - _ . . . - _ . _ _ _ _ h ( 11.5 FURTHER EVALUATION OF RETAINED ALTERNATIVES ! l Further efforts are required to evaluate the efficacy of each of these alternatives. These efforts I have been identified and are underway. r For evaluation of gridded physical baniers directly on or offset from the intake structure, actions i to date have included: f
- Completion of a preliminary assessment of barrier options.
- Review and analysis of the plant's current intake structure design bases.
1
- Literature search and discussions with marine mammal specialists at research institutions and major commercial aquariums that maintain seals. ,
e Retention of pinniped research specialists as advisors and reviewers to the Seabrook Station Marine Mammal Protection Project. For evaluation of the potential use of ADDS to deter seals from the intake structure, actions to 1 date have included:
- Literature review and contacts with researchers and potential ADD system vendors.
- Retention of ADD and ocean engineering specialists as advisors and reviewers to the !
Marine Mammal Protection Project. l 35
i 5
- Completion of a preliminary report assessing the efficacy of an ADD system deployrnent for deterring seals from the Seabrook Station intake that considers ;
alternative power supply, charging system and platform options. ; i
.. I i
Actions are underway to complete conceptual design and feasibility assessments for these alternatives. l l, I i i i d 1 1 a s I J l i I i i 36
-_ . . - . - .. ~-_ __. ._ __ _ _ _
I i
- 12. Where the proposed activity would take place in or near a traditional Arctic subsistence
.- hunting area and/or affect the availability of a species or stock of mammal for Arctic subsistence uses, the applicant must submit either a plan of cooperation or information that identifies what measures have been taken and/or will be taken to minimize any adverse effects on the availability of marine mammals for subsistence uses.
The activity does not take place in or near a traditional Arctic subsistence hunting area and does not affect the availability of a species or stock of mammal for Arctic subsistence uses. 1 I l l i i l 37
13.The suggested means of accomplishing the necessary monitoring and reporting that will result in increased knowledge of the species, the level of taking or impacts on
.. populations of marine mammals that are expected to be present while conducting activities and suggested means of minimizing burdens by coordinating such reporting ** 1 requirements with other schemes already applicable to persons conducting the activity. '
Monitoring plans should include a description of the survey techniques that would be used to determine the movement and activity of marine mammals near the activity site (s) including migration and other habitat uses, such as feeding. l The seal monitoring activities at Seabrook Station consist of a nearfield monitoring program focused on the local seal population at Inner Sunk Rocks (Figure 1), and an in-plant program to j detect and investigate the entrapment of seals. In addition, the aerial survey of seal populations along the coast of Maine, conducted by Dr. James Gilbert of the University of Maine, has been extended to include coastal New Hampshire for 1997 and future surveys. j Nearfield Monitoring The objective of the nearfield monitoring project is to determine if there is any correlation between the observed relative seal abundance at Inner Sunk Rocks and entrapment of seals at Seabrook Station, and to develop a relative index of the size of the seal population near Seabrook i Station. A weekly count is presently being be made of the number of seals hauled-out at low tide l at a time between 0800 and 1600 hours on the Inner Sunk Rocks. The count is made using binoculars from a stationary boat in the navigation channel to Hampton Harbor, which is less i
- than 400 yards from the Inner Sunk Rocks. Ifit is not possible to make the weekly observations i from a boat due to extended foul weather, observations will be made from the beach or from I
38
l l l l them to enter the water. Observations began in March of 1997 and the number of seals observed l l 1 in weekly surveys to date are shown in Table 5. In addition, sightings of any marine mammals observed are recorded in a log book as part of the overall Seabrook Station Environmental l- Monitoring Program. Information collected will include time and date, tentative species l identification, approximate size, and direction of travel. 1 In-Plant Monitoring l Daily visual inspections of the water surface in Seabrock Station's Circulating Water System and Service Water System Forebays are performed by Seabrook Station Operations Department staff using a high intensity hand-held light. At least once per week, a screen wash debris inspection i and assessment is also made for evidence of seal remains. If a seal or seal remains are observed, ! they are recotered and maintained by either freezing or refrigeration and delivered for identification and necropsy to the New England Aquarium in Boston, Massachusetts. Observations irrde and recorded by the New England Aquarium staffinclude the species, age, sex, weight, general health, and stomach contents of entrapped seals, when possible (see Table i 2). During refueling outage shutdowns, the forebays are inspected by divers and any indications of seal remains are reported. l The National Marine Fisheries Service (NMFS) in Gloucester, Massachusetts is immediately notified by telephone when an intact seal carcass is identified either in the forebays or in screen wash debris and a written report is submitted to the NMFS within 14 days. 39
, 14. Suggested means of learning of, encouraging, and coordinating research opportunities, i plans, and activities relating to reducing such incidental taking and evaluating its '.. effects. l'- As described in Section 11, North Atlantic is currently conducting detailed evaluations of methods to prevent or reduce the lethal incidental taking of seals through the Seabrook Station ! intake structures. North Atlantic is studying the suitability and effectiveness of the use of acoustic deterrents with marine biologists, pinniped behavioral experts and engineers. A similar l evaluation of the suitability and effectiveness of physical barriers on the intake structures is being conducted. t l l l 1 i l 1 e 40
1 LITERATURE CITED ' Barlow, J., S. L. Swartz, T. C. Engle, and P. R. Wade.1995. U.S. Marine Mammal Stock Assessments: Guidelines for Preparation, Background, and a Summary of the 1995 Assessments. U.S. Dep. Commer., NOAA Tech. Memo. NMFS-OPR-66, 73 p. Blaylock, R.A., J.W. Hain, L.J. Hansen, D.L. Palka, G.T. Waring.1995. U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments. NOAA Tech. Memo. NMFS-SEFSC-363, 211 p. Bonner, W. N.1990. The Natural History of Seals. Facts on file. l Brown, R.F. and B.R. Mate. 1983. Abundance, movements, and feeding habits of harbor seals, Phoca virulina, at Netarts and Tillamook Bays, Oregon. Fishery Bull. 81(2):191-301. Hall, E.R. and K.R. Kelson.1959. The Mammals of North America. The Ronald Press Company, NY. Katona, S., D. Richardson, R. Hazard. 1975. A Field Guide to the Whales and Seals of the Gulf of Maine. Maine Coast Printers, Rockland Maine. 97 pp. Katona, S., V. Rough, and, D. T. Richardson.1993. A field guide to whales, porpoises, and seals from Cape Cod to Newfoundland. 4th ed. Washington: Smithsonian Institution. 316 p. Kenney, M.K. and J.R. Gilbert. 1994. Increase in harbor and gray seal populations in Maine. Dept. of Wildlife Ecology, University of Maine. Prepared for National Marine Fisheries Service, Northeast Fisheries Center, Woods Hole, MA. l Mate, B. R., and J. T. Harvey (editors).1987. Acoustical deterrents in marine mammal conflicts with fisheries. Report on a workshop held February 17-18,1986 in Newport, Oregon. 116 p. Oregon Stat Univ., Sea Grant College Program, Publ. no. ORESU-W-86-001, Corvallis, Mohn, R. and W.D. Bowen. 1994. A model of gray seal predation on 4VsW cod and its effects on the dynamics and potential yield of cod. DFO Atlantic Fisheries Res. Doc. 94/64. Mooney-Seus, M.L. and G.S. Stone.1995. Pinniped Populations in the Gulf of Maine, Status, Issues and Management. New England Aquarium Aquatic Fonun Series Report 95-1. Morris, D. S.,1996. Seal predation at salmon farms in Maine, an overview of the problem and l potential solutions. Mar. Tech. Soc. Journal. 30(2): 39-43. 41
LITERATURE CITED (continued) National Marine Fisheries Service (NMFS).1995. Environmental assessment of proposed regulations to govem interactions between marine mammals and commercial fishing operations, under Section 118 of the Marine Mammal Protection Act. U. S. Dep. Commerce., NOAA NMFS Office protected Resources.138 p. National Marine Fisheries Service (NMFS).1996. Report of the Gulf of Maine Aquaculture-Pinniped Task Force. Silver Spring (MD): NMFS. 70 p. National Marine Fisheries Service (NMFS).1997. Investigation of Scientific Information on the Impacts of California sea Lions and pacific harbor seals on Salmonids and on the Coastal Ecosystems of Washington, Oregon, and California. U.S. Dep. Commer., NOAA Tech. memo. NMFS-NWFSC-28,172 p. Norberg, B., and D.E. Bain.1994. Implementation and assessment of the acoustic barrier at the Hiram M. Chittenden Locks using calibrated measurements of the sound field. I Normandeau Associates Inc. (NAI).1996. Seabrook Station 1995 Environmental Studies in the Hampton-Seabrook Area. A Characterization of Environmental Conditions. Prepared for North Atlantic Energy Service Corporation. National Marine Fisheries Service. February 25,1982. Letter from R. Rehfus (NMFS) to F. Miraglia (NRC) Padmanabhan, M. and Hecker, G.E.1991. Comparative Evaluation of Hydraulic Model and Field Thermal Plume Data, Seabrook Nuclear Power Station. Alden Research Laboratory Inc. l Paton, D. 1988. Gray seals establish critical marine habitat in Nantucket Sound. Biol. Bull. Mar. Biol. Lab. Woods Hole. 175:312. Payne, P.M. and D.C. Schneider.1984. Yearly changes in abundance of harbor seals, Phoca vitulina, at a winter haul-out site in Massachusetts. Fishery Bulletin. 82(2):440-442. Reeves, R. R., R. J. Hofman, G. K. Silber, and D. Wilkenson. 1996. Acoustic deterrence of harmful marine mammal fishery interactions: proceedings of a workshop held in Seattle, l Washington,20-22 March 1996. U.S. Dep. Commer., NOAA Tech. Memo. NMFS-OPR-10,68
. P.
Riedman, M. 1990., The Pinnipeds, Seals, Sea Lions, and Walruses, University of California
- Press.
! Rosenfeld, M., M. George, and J.M. Terhune. 1988. Evidence of autumnal harbour seal, Phoca virulina, movement from Canada to the United States. Can. Field-Nat. 102(3):52777-529. 42
l l LITERATURE CITED (continued) ]
)
Rough, V. 1995. Gray seals in Nantucket Sound, Massachusetts, winter and spring,1994. Final ,
.. report to Marine Mammal Conservation Commission, Contract T10155615, 28 pp. NTIS Pub l PB95 - 191391.
Shelton, P.A., N.G. Caddigan and G.B. Stenson. 1992. Model estimates of harp seal production trajectories in the Northwest Atlantic. CAFSAC Res. Doc. 92/89,23 p. ; i Stenson, G.B.' 1993. The status of pinnipeds in the Newfoundland region. NAFO SCR Doc. ! 93/94. ! l
. Schneider, D.S. and P.M. Payne. 1983. Factors affecting haul-out of harbor seals at a site in southeastern Massachusetts. J. Mammal. 64:518-520. .
I Stobo, W.T and K.C.T. Zwanenburg. 1990. Grey seal (Halichoerus grypus) pup production on l Sable Island and estimates of recent production in the northwest Atlantic. Pages 171-184 in W.D. Bowen (editor), Population biology of sealworm (Pseudoterranova decipiens) in relation to its intermediates and seal hosts. Can. Bull. Fish. and Aq. Sci. 222. Sullivan, R.M. 1980. Seasonal occurrence and haul-out use in pinnipeds along Humboldt County, California. J. Mammal. 61:7754-760. Tillapaugh, D., C. Brenton, and B. Harrower. In press. Predation on salmon fanns in British Columbia; the impacts of harbour seals, Phoca ritulina. Study funded by the BC Ministry of Agriculture, Food, and Fisheries. 49 p. ; U.S. Nuclear Regulatory Commission. December 1982. Final Environmental Statement Related l to the Operation of Seabrook Station. NUREG-0895. ! Whitman, S.C. and P.M. Payne. 1990. Age of harbour seals, Phoca ritulina concolor, wintering in southern New England. Can. Field-Nat. 104(4):579-582.22 e J G l \ 43 l I... - -
- e
i 4$ TABLES AND FIGURES 1 a i 1 i e n
t
> able 1 l
' Intact Seal Carcasses )
.. Recovered by Month j 1993 to 1996 :
(All were Harbor Seals) ! 1 Jan 0 ; Feb 0 3 Mar 0 Apr 0 ! May 0 , Jun 1 ! Jul 0 Aug 5 Sep 3 Oct 6 Nov 2 Dec 1 TOTAL 18 , f f i l l l T-1
. . i ;
Tchle 2 Observations of Seal Remains at Seabrook Station by Date Including Necropsy Results Where Available Description (Remains recovered Date from screen wash debris unless Necropsy Results (All necropsies performed by the New England Aquarium, maless otherwise Observed : otherwise noted) - noted ). 10/25/93 Intact seal carcass recovered. Ilarbor seal. 12/93 Several seal bones. Bones were from a seal as identified by a local medical examiner. 10/94 Seal skull. No recorded information. 10/27/94 Intact seal carcass recovered. l{ arbor seal. 10/27/94 Intact seal carcass recovered. Ilarbor seal. I1/07/94 Intact seal carcass observed in SW A New England Aquarium Tag was recovered from screen wash debris on 11/23/94. This tag could Forebay and not recovered. have been from the seal observed on i1/7/94. According to the New England Aquarium the tagged seal was a male four month old harbor seal pup, rescued and treated by the Aquarium and released with this tag from Biddeford, Maine on 9/25/94. I1/30/94 Two seal skulls. One probably from No recorded information. seal observed on 11/07/94. I1/30/94 Seal skull. Probably from seal not No recorded information. previously observed. 01/24/95 Seal skull. Probably from seal No recorded information. entrapped in late 1994 and not previously observed. T-2
, , Tcble 2 (continued) i ;
Observttions cf Se:1 R:mniis ct Se: brook Stitica by Data Incl:;dirg Necropsy Restits Where Avcilable Description (Remains recovered - . Date . from screen wash debris unless- Necropsy Results (All aceropsies performed by the New England Aquarium, unless otherwise , Observed - otherwise noted) . noted) . - 03/14/95 Seal skull. Probably from seal Harbor seal. entrapped in early 1995. 05/23/95 Seal skull. Probably from another seal Hooded seal (probable identification based on limited skull fragments. entrapped in early 1995. 06/23/95 Intact seal carcass recovered. Seal Harbor seal. appeared to have been entrapped recently. In good condition. 08/16/95 Intact seal carcass observed in CW No recorded information. Forebay and not recovered. 09/21/95 Intact seal carcass observed in SW No recorded information. Forebay and not recovered. I1/14/95 Intact seal carcass observed in SW No recorded information. Forebay and not recovered. 12/19/95 Partial skull. Probably from seal Harp seal. observed in either 8/95 or 9/95 or a seal not previously observed. 06/07/96 Skull fragments. Probably from seal Harbor seal. Frontal skull bones and attached crania from young-of-the-year. observed in either 8/95 or 9/95 or a seal not previously observed. 08/09/96 Intact seal carcass recovered from SW Harbor seal. Forebay. 08/13/96 Skull fragment. No recorded information. T-3
TLble 2 (continued) 4 Oldervatioins cf Seal Rentins ct Seabrook Station by Date Imeluding Necropsy Results Where AvcitEble Description Steneales moval .. .. . Date o freni sestem wash debris unless; - Necropsy Results (All meeropsies perforened by the New England Aeguarisen, unless otherwise Observed 4 otherwise noted) ' noted) . 08/27/96 Skull fragment Harbor seal. Partial cranium and first cervical vertebrae and nasal bones from a sub adult (estimated 1-3 years old). 08/27/96 Skull fragment. Harbor seal. Occip il bone and lowerjaw from a you'g-of-the-year. It is possible the skull is from one of the seals whe remains were recovered on 6/7/96. Bone pieces are too badly damaged and worn to reconstruct for certain. 08/27/96 Intact seal carcass recovered. Harbor seal. Young-of-the-year female about 40 lbs. and 85 cm. long. Badly decomposed. Seal appears to have been in good health. No parasites. Stomach contained 1.5 lbs of recently ingested stomach contents. Appears to have been entrapped while or shortly after feeding. 09/08/96 Intact seal carcass recovered from SW Harbor seal. Young-of-the-year male about 40 lbs. and 89 cm. long. Badly decomposed. Seal Forebay. appears to have been in good health. No parasites. Stomach contained recently ingested fish parts. Appears to have been entrapped shortly after feeding. 09/14/96 Intact seal carcass recovered from CW Harbor seal. Young-of-the-year female about 45 lbs. and 93 cm. long. Badly decomposed. Seal Forebay. appears to have been in good health. No parasites or signs ofdisease. Stomach contained a few fish bones. 09/17/96 Intact seal carcass recovered from CW Harbor seal. Young-of-the-year male about 45 lbs. and % cm. long. Moderately decomposed. No Forebay. sign of prior disease or parasites. Signs of hemorrhage around thorax indicates probable live entrapment. No stomach contents. I T-4
, , Tchle 2 (e cti2xed) i ;
Obs:rvctioIs cf Sect R:mnirs ct Secbrook St tion by D:te Ircludi;g Necropsy ResIlts Wh:re Av;;il;ble Description (Remains recovered Date from screen wash debris unless : Necropsy Results (All secropsies performed by the New England Aquarium, unless otherwise Observed otherwise noted) ' noted ). 10/20/96 Intact seal carcass recovered. 11 arbor seal. Young-of-the-year male about 40 lbs. and 90 cm. long. Decomposed around head, front and rear flippers. Average to fair body condition forjuvenile seal. No sign of prior disease, significant parasites or trauma. Seal appears to have been in good health and feeding immediately prior to entrapment. Stomach contained about 300 grams ofsemi-digested fish and squid beaks. 10/20/96 Intact seal carcass recovered. liarbor seal. Young-of-the-year female about 45 lbs. and 90 cm. Iong. Average to good flesh with slight decomposition. No sign of prior disease or significant parasites, hemorrhage into anterior chamber of both eyes, some slight superficial bruising around left eye, light ectoparasite load on head and rear flippers. Seal appears to have been in good health and feeding regularly immediately prior to entrapment. Shows signs similar to seals recovered from nets (eye hemorrhage). Signs are consistent with live entrapment during feeding. 10/20/96 Intact seal carcass recovered. Ilarbor seal. Young-of-the-year female about 45 lbs. and 87 cm. long. Average to good flesh with slight decomposition. No sign of prior disease, significant parasites or trauma. Seal appears to have , been in good health and feeding immediately prior to entrapment. Stomach contained about 200 grams of semi-digested fish. 12/31/96 Intact seal carcass recovered from SW liarbor seal. Adult male about 150 lbs. and 130 cm. long (approximate due to decomposition). Forebay. Appears to have been an average to well fleshed adult seal. Seal was decomposed, pieces of skull and flippers missing skin and blubber sloughing. Poor condition ofcarcass makes determination difIicult, however, seal appears to have been robust adult male with no serious pre-existing disease or heavy parasite load. Seal appears to have died suddenly shortly after feeding. Stomach contained 400 grams of semi-digested fish. 4/29/97 Two skull fragments. Probably from Probably a single Ilarp Seal based on skull fragments provided to the New England Aquarium for one seals entrapped in late 1996 and analysis. not previously observed. T-5
i 1 Table 3 l Estimated Seal Entrapments by Year 1990 0 1991 0 1992 0 j , 1993 2 1994 7 l 1995 6-7 1996 12-17
)
1
- 1997 (Through May) 0 TOTAL 27-33 1
a T-6
Table 4 Preliminary Screening Matrix-Technology or Measure vs. Evaluation Criteria
- ^ (Ehd$NakCrHiera fD E seiisology;ossessSrel , EM isii ici JD{ % Mi l{Gf % j E
((omment6 - l 5 g Redesigned intake- visual or p- - nd nd nd nd nd nd No designs were identified that would represent a visual or behavioral deterrent. behavioral deterrent Predator models, e.g., life-size p- - + + + + nd + Documented success with predator models, with and without associated acoustic floating killer whale model signals (see item below) has not been demonstrated for long-term application. Recorded predator sounds- p- - + + + + nd nd (see above item) e.g., killer whale Suspended net barrier outside nd - nd nd - - nd nd No demonstrated use of this technology was identified that could withstand of periphery of area possible direct impacts of strong winds and heavy seas associated with the encompassing the three intake relatively shallow water and Open coastal location. Concern for safety to cooling structures water system or local boaters if nets became loose. Uncertain effectiveness regarding seals traversing the top of the net. " Cage" structure outside p+ - nd nd - - nd nd No demonstrated use of this technology. Concerns for design, installation, periphery of three intakes or maintenance, hazards to navigation, potential fouling and blockage with debris. each intake singly " Bubble curtain" - - nd nd p- nd nd nd No demonstrated application of this technology. Intake currents would draw bubbles inward. May attract seals to vicinity of the intake. Ineffective during storms. Uncertain efTectiveness overall. Translocation of seals from - - nd + - nd nd + Unrealistic. Seals are thought to be migrating from other areas (particularly, vicinity southward during fall /carly winter months). There is no way to identify and remove seals that would have a greater likelihood of being entrapped in the intake tunnel. Unidentified behavioral - - nd nd nd nd nd nd None identified. deterrent A= Effectiveness; B= Proven in some application; C= Nuclear Safety; D= Operations and Licensing; E= Implementable; F= Economically practicable; G= Agency Acceptability; II=EITects on non-target species. Preliminary Evaluation Code: "+" positive, " " negative for this criterion; "p+" probable positive,"p " probable negative for the criterion; "nd" not determined, need additional information to fully evaluate. T-7
l l
;g EvaluatiesCWeiers[
.p : ~: .;ra $f.
?--ws TD' & , . . . . . #
-;. +. :.:. '+Je :::. e.=c:? , . m. f...<.--:.- -m .ep
~j 3+ + t: - F: ^
S';il;; yy:J TBf JCi yE3 @p,m FE , , , , ,Pc ^ - Comments :
- TeetestegyetMeasure s ?AT
~ ws e:wA w~
RD1: TG:s , e.. ai mi+wn- W
- ~ we% '
-' - " - - - ~-
- <~ ~
> vy+w Add small grid-space barrier + -
nd nd nd nd p+ nd Physical barriers represent the most direct way to prevent seals from entering the to existing 16" vertical bars intake and getting entrapped into the intake tunnel. Primary issues are the potential impacts on operations and licensing, nuclear safety, cost of design, fabrication, and installation, and operations and maintenance, specially due to marine biofouling and fouling with debris. Redesigned intake- physical + - nd nd nd nd p+ nd if intake design will not accommodate smaller spacing at the location of the barrier ofTset to existing present 16" spacing vertical bars, design of an offset stnacture that will velocity cap accommodate smaller spacing while maintaining flow will entail greater cost and require greater analyses and Operating License review. Acoustic Deterrent Device + + nd p+ p+ nd nd p- Effectiveness of recently developed AIRMAR dB plus demonstrated but without similar to ADD's used at scientifically supportable data. The acoustic deterrent technology itself should be nearshore salmon farms effective. Problem with providing continuous power offshore. Concem for operations and maintenance. Concern for potential habitat exclusion for species of marine cetaceans. A=EfTectiveness; B= Proven in some application; C= Nuclear Safety; D= Operations and Licensing; E= Implementable; F= Economically practicable; G= Agency Acceptability; H=EfTects on non-target species. Preliminary Evaluation Code: "+" positive, " " negative for thi.; criterion; "p+" probable positive,"p " probable negative for the criterion; "nd" not determined, need additional information to fully evaluate. T-8
l l Table 5 Nearfield Monitoring l
~
of Seals on Inner Sunks Rocks (1997) i Daic Number of Stah 5 Mar 42 11 Mar 31 ! 17 Mar 48 24 Mar 35 3 Apr 45 10 Apr 11 ! 16 Apr 47 l 23 Apr 26 l 30 Apr 38 l l 5 May 16 13 May 53 19 May 17 I 29 May 1* l 3 Jun 3 I
- Heavy small boat traffic in area.
l l I a
\
i T-9 l l
i Fignre 1 Scabrook Station Ocean Cooling Water System
**' +
~
" la- Atlantic
, .. Seabrook -~ ",
I totake Shalts Plant Site - 9,j 4
, 4 Ocean p and Structures w _ , , > -
2 pac- 4t#gu i * = Q .== #1 gs
^ .
^ ^ Hampton 3
- d-Harbor w ~ ,. -.
W \ DISCHARGE TUNNEL
.fE T TY [n'dY8tu r orzieS s , - ~ ,3
.v - , ,
.3 e
, . e d3
]3 A es
- a i 7 A nner I Sunk Rocks Seabrook intake velocity caps Plant l ," ~ ~ - - c-
. - -- 4 '
~
' ^^
,N ps '
- OVERBURDEN - \ * """
d and land
* ~ ' ' '
\ ,'
- 10 0-Shatt M
D,'
.t ROCK
,' . 19'ID Shaf t ,,.10 Coac'et' L 3"ed Tunnet t' . _ _ . . . . _ . . . . . . ... ......_. .._.. tG.4 83 Feet -
Scabrook Station Cooling Water System:
. Intake structures (three) are about 7,000 feet o(Tshore
. Intake tunnel is about 17,140 feet long -
. Discharge structures (cleven) are about 5,500 feet offshore
. Discharge tunnel is about 16,500 feet long
30'-6" 01 A.
-e m l
l I
/
/
f I / f N d:; J
' 's '
7 VANES
\ s N ,-
(12 TOTAL) 1 ' -O f' X 7 ' -0 "X 8 ' -6 '
, l,\Ny -
GUARD BARS (REMOVED FOR CLARITY)
/ 2 " x l q" i x 7 ' -0" GUARD BARS '
I (e 16') I i SECTION A-A I - 1 i 1 . l 1 Figure 2 Seabrook Station Intake Velocity Cap i
Figur: 3 Scabrook Station Intake Velocity Cap _- - - --- PREFABRICATED = - - -- ^^
^
. ' COPPER- '
- ^
- ~ ~_ _ REINFORCED 1.:^_ _:'_: : ^ .: ~. . : .
- :: NICKEL
_: __~ __::__ :: ::..._ CONCRETE _ _ _ _ _ _ . . . . __ _ O_ _V M-_ g M _ _ g g _:_ _ . . _ CLADDING x .__ _ _
^
~^ ~
--5.~;5 4,.;Li idiNh'"-Tffi'$,$ffM$Ninu-/h ~- ~ ~ ^ 2 ^ E
- - VANES
'. VANES _ - - _. . ..
b GRILLAGE
~
^- ~- :~~
~
'~
GRILLAGE _J_ - _DA_RS ___ DARS__
----_: :- ^ ::_ ::______: _::, _ __ ..
gf*' aTJF
- DM'Oni[2?A,*/p :;' - --: -:-:
E6biisii."^rrTp..jj'r ::::: @ M igd "cr:7,fMap rrr:: - :
'ik ' ~
i < W.-. ~^_ANCHORAGE GROUT NICKEL ~:-:: _ : ~ _ . _ :'_: _^._ ^: _::_ - ~^f CLADDING - . . _ --- __. .
~
.h. ,_ _
-^2~~^2 -
PREFABRICATED # d:^'_ - ::: OCEAN [7
~~~~ ^^^~
OR F REINFORCED ' 1* ' - ^ . Z - ^ ^ ~ -- CONCRETE -f-{^{-{}
^^ ^ ^^-
.. .: i n.,pp% N.. M; i:%Q%N$ . 4 m .__:_::^^~
"$ OVERBURDEN-, .__.
. i' ' ,A. jj . , %d'J,i i ^ :: ::^: Vf% M h,$8NN, '
_r -
~"
= p '
;:; ':-::: F 3Rgyggs A 5
5] OUTER STEEL . SHELL . l
.d U E,DROCK 4 g ., BE 1 p -- --__.
- -- * ,12' DIAMETER
'i PREDRILLED HOLE u p4
" n N. l. .
.j^:^^_^^ <
? j l
l, - 5" MORTAR 4 i
^ ^~'"^~ U-L
* 'p" n $ LINING - ^ ^ '^^^
E
}h me{.,QR_j,IVEf5eJhne Y
C . I
.3.1 p.;; ;
h I k 1 4
- - e .
Figure 4 Seabrook Station Circulating Water System Pumphouse REMOVAL If ATCil MONORAll STOP
.. / \ "' LOGS F ,
7 ( Q, T T % / y <-
; UVER ,
t
.' - TRAVELING ,
CIRC WATER ,1 - SCREENS PUMPS gg7-) FLOOR EL 21* ~
}[, f" i
{]
- " "M h' _d'. I GRADE EL 20*-0" INTAKE TRANSITION
- . STRUCTURE
- '- FL 4*-0" , , _
.p' PUMP PIT FLOOR, rz 7 ,!_ !
f '., EL (*)3'-0* K
. 64" DUTTERFLY- U e . .. .,
VALVE !, , - o .. _ PP ' FLU'J b4i ]*]'YIpp: . T -? i{'j f g A > EL (-139*-10" g ; t '- m _,.r ,6 ,,. ji',,,, j[
.[g
, '.c , . S ..
,7 f.. _
,,j.}
El (-)43'-0" T '~ DACKWASH CONDUITS ' [/ '
}'
s g EL (-)61*-0" , yi ,,,
. . t, ,
Figure 5 - Scabrook Station Service Water System Pumphonse REMOVAL Atn ntScilAftGE ggAICli VENiltAltON " I "' , \ Missit E St eit t D [ l ( [j k; 3fiff i",'i rija qu ,,_ Jb a 3Tk 2 NtMW'E C W M L Al E g_, vFNtit AllON
'^
VENitt AYlON i 7 [8 ' g.'n, '.-j .y Mnli^S
- '- Ui ; VENillATION FNinANCE I WASit inAVEttNO DAMPEN n-
SEDVICE Win SC,nEEN upS MISSitt ,
, SCf1EENS -
, MISStLE SHIELD ME fp jj SHIElO , ._' . goU P , t3 STOP LOGS Ptf MP nOOM = f1E MOV Ant E l ,.,
UnAleNG s .' 4 Ft00n EL 28'-0" [jj 1 , i
"$ S N $-4-jj' h yMf9Sh
, ; 57 # N T,'n'A%n$,'c['. at I' ,* .' PIPING Pli .l, 1
L.'t, - e.',
..;, e af.-
- e) 8 L OOf1 Et 4 -o- i-' f aala2 n' n Kag 8'y p MEAN SEA LEVEL di El tr o-h-
e; l M y!,.'.a e ci, , ronE w.' i Y' BAV BAY
,9 f, fi6 l' '
- P :
v.
- )
4 bb _ r E - l1 ' i g . SEnVICE WATED fHLEIS f,j c
- '.,' tt gjetr*0*
s t oon ti. s nu-er- ..
, g; g,y , n a.- g 4.g;,;)]
Figure 6
'~
Grid Spacing on Existing Intake Velocity Caps
. .- , il ll 11 Il ll ll ll ll .
il 11 ll ll li il 11 ll ,
. Il ll 11 ll ll 11 ll ll
~ ~ . Il ll 11 ll ll ll Il ll .
ll 11 ll ll Il il 11 11 . l ll ll ll 11 Il 11 ll 11 '. i -
~
!! 11 11 11 Il ll ll 11 '
l
-11 ll ll ll ll ll ll Il '
l
- Il ll ll 11 ll ll 11.Il l
Additional Vertical Bars Additions' Vertical Bars
& New Ho.izontal Bars e
i']'l ,l!Ill !
)
, 2
/
.*- ~
- 2. *
- o ,
j.
~
%'Q n I
o8e-
\
- ?:
r6; d hw, ; i i! l a l P [7, 'y,', .. f( p g y El:, . \
' g <
g . p r e dr r a i e n r r d 7 a
$i d c B :
c r d r: u i r i s j'4 . g : a > i F G - t t l-t e
- t o T
I s
- I I
1_ O I , I T 1_ 1
/
.)
r ;
- . i, o
"6 e
'0 u l I I t o
3 v e a r
, ,i 3 .
I
\ .
,l x
- ' . l -
1' u
.S e ur b
?l*
' o n
d u c tl1 l1llll
D l S l p I n e t o s y n s S n t n e e g o t n s n o in e i t A P r i r p o e O y r t t r a in t n g o n t l o e o M B t oo i n S i r - e ict D o rc S o le - . te M T - cn _ ll J :
- l e no I 8 'e
_ : E c
- .C e i
. r v p e Il u
% i i
g D t F n g e r h r . t e e D i c t s - n u e o t c s A y S g n ir o
. o . M l
o l S I lll' l}}