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HomeMy WebLinkAboutFI Metal Dump Feasibility Study - Prelim . ( co c'~' . . TOWN OF SOUTHOLD SUFFOLK COUNTY, NEW YORK FEASmILITY STUDY -, FOR CWSURE OF THE ~ FISHER'S ISLAND METAL DUMP ( \\t\.\ \\ \~~\\'l Y '. PREPARED BY: FAGAN ENGINEERS Environmental Consultants 113 East Chemung Place Elmira, New York 14904 MARCH 1994 , .,,' . .. -, - >,'~_f-:.:",,~ ," '(~'.-...:~': -;.-~~~_, ~-'-; - ><_:1,~:.. ."._.;:__.:~-~,,^ "'>""'~'" , -> .. .'::"-:j>',li:_,:,;,-;.,:,iJi..-0"f,'_''''I''~>'~~'d,,"'-',","-~, .o;.y;.;-1A"'" ,"k~:;::..f 2:~.,:;;'Qi(,'€'~-;)~t,~;:d,!-''-; .~_~~,~,_:e:s.i!lI;; _' ...~":"JP:~~.'j"'-"" ~""'"'~-~l:1iMI ( ( c . . . TOWN OF SOUTHOLD, N. Y. FEASIBILITY STUDY FOR CWSURE OF THE FISHER'S ISLAND METAL DUMP TABLE OF CONTENTS CHAPTER TITLE PAGE I. INlRODUcnON A Background & Existing Site Conditions . . . . . . . . . . . . . . . . .. 1 - 1 B. Purpose of Facility Closure .... . . . . . . . . . . . . . . . . . . . . . " I - 4 C. Purpose of This Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1 - 7 II. CLOSURE ALTERNATIVES A Removal of All Solid Waste from Site . . . . . . . . . . . . . . . . .. II - 1 B. Bale & Replace Metal in Pit, Remove Other Wastes. . . . . .. II - 3 C. Removal of All Solid Waste from Eastern Pit ............ II - 6 D. Bale & Place Metal from Eastern Pit into Bunker, ........ II - 8 Remove Other Wastes E. Installation of Final Cover with Solid Waste in Place. . . . . .. II - 9 Over Eastern Pit III. RECOMMENDED CLOSURE ALTERNATIVE.....;........ III - 1 Appendix A Engineering lUld Cost Calculations Appendix B Historical Preservation Funding LIST OF TABLES TABLe NO. TITLE PAGE NO. 1- 1 Solid Waste Volume Estimate ............... . . . . . . . .. I - 3 II - 1 Cost Estimate Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . II _ 4 LIST OF FIGURES FIGURE NO. FOLLOWS PAGE NO. TITLE 1- 1 Regional Map ................................... . 1 - 1 1-2 Location Map ................................... . 1 - 1 Engineering Drawings ........................ Rear Pocket Sheet No. 1 - Existing Site Conditions TC -I . . ( I. INTRODUCfION A. BACKGROUND & EXISTING SITE CONDITIONS Fisher's Island is a 4.25 square mile island with a year round population of approximately 300 located 4.5 miles southeast of New London, Connecticut. Politically, Fisher's Island is part of the Town of Southold, New York on Long Island, some 12 miles to the southeast (See Figure I - 1). Principle access to the island is via ferry from New London. A small airport also serves Fisher's Island. ( From 1910 until 1946, the western end of Fisher's Island was occupied by Fort H. G. Wright, a U. S. Army coastal artillery installation. This fort provided protection for the entrance to Long Island Sound and the Thames River in Connecticut from enemy warships and submarines, principally during World War I. The fort was abandoned by the army following the end of World War II with ownership being transferred to the Town of Southold. Since then, a number of parcels have been sold off to individuals. However, a large portion of the fort remains the property of the Town (See Figure I - 2). Within the perimeter of the fort are a number of reinforced concrete gun pits which actually housed the 16-inch diameter stationary shore guns. Each of the pits is typically excavated 12 to 15 feet below grade with three reinforced concrete walls and a reinforced concrete floor specifically designed to support a gun and it's turning gear. In all cases, one side of each pit remained open for access to the guns. In addition to the gun pits, a number of ammunition magazines and other support structures were also constructed with reinforced concrete walls and vaulted ceilings. These concrete structures remain essentially intact today but in many cases are overgrown with vegetation. Since just after the fort was abandoned in 1946, Fisher's Island residents have used two gun pits located at the eastern end of the fort for disposal of solid waste. The easternmost of these pits became known as the "Metal Dump" by residents and was used for the dumping C' of metal items as late as 1992. The western pit was first used as a general municipal waste 1- 1 . . NEW (6.) I I ' \ YORK\ STATE //~--- \ J-0)-- e /~# ~S ISLA:; ( ~__---f CONNECTICUT ~ ;t..;...~ .....'\... --- c11~ co~ 101ll --~.. NEW JERSEY ( NEW YORK STATE TOWN OF SOUTHOLD SUFFOLK COUNTY, NEW' YORK FIGURE I - 1 REGIONAL MAP NOT TO SCALE FISHERS ISLAND JlETAL DUllP CLOSURE FEASIBILITY STUDY. JURCH. 1994 c J08/94.010 r '- ( c . . 00-Q SO lIfCOPESSET ISLAND " ~0-Q ,S"-' EAST POINT (r'S ~,S0 N. DU10IPUNG t) (UQiT HaJgJ ~ FZ.A T S. DUUPUNG t1 HAJ.IJJOCK 00-Q SO ~0-Q ,S"-' Oc'f- 0V . METAL DUMP SITE TOWN OF SOUTHOLD. SUFFOLK COUNTY, NEW YORK FIGURE I - 2 LOCA TION MAP NOT TO SCALE FISHERS ISLAND JUrAL DUJIp CLOSUl/E F8AS1B11JTY STUDY JURCH, 1994 . . r . " I. INTRODUCfION A. BACKGROUND & EXISTING SITE CONDITIONS Fisher's Island is a 4.25 square mile island with a year round population of approximately 300 located 4.5 miles southeast of New London, Connecticut. Politically, Fisher's Island is part of the Town of Southold, New York on Long Island, some 12 miles to the southeast (See Figure I - 1). Principle access to the island is via ferry from New London. A small airport also serves Fisher's Island. ( From 1910 until 1946, the western end of Fisher's Island was occupied by Fort H. G. Wright, a U. S. Army coastal artillery installation. This fort provided protection for the entrance to Long Island Sound and the Thames River in Connecticut from enemy warships and submarines, principally during World War I. The fort was abandoned by the army following the end of World War II with ownership being transferred to the Town of Southold. Since then, a number of parcels have been sold off to individuals. However, a large portion of the fort remains the property of the Town (See Figure I - 2). Within the perimeter of the fort are a number of reinforced concrete gun pits which actually housed the 16-inch diameter stationary shore guns. Each of the pits is typically excavated 12 to 15 feet below grade with three reinforced concrete walls and a reinforced concrete floor specifically designed to support a gun and it's turning gear. In all cases, one side of each pit remained open for access to the guns. In addition to the gun pits, a number of ammunition magazines and other support structures were also constructed with reinforced concrete walls and vaulted ceilings. These concrete structures remain essentially intact today but in many cases are overgrown with vegetation. Since just after the fort was abandoned in 1946, Fisher's Island residents have used two gun pits located at the eastern end of the fort for disposal of solid waste. The easternmost of these pits became known as the "Metal Dump" by residents and was used for the dumping (" of metal items as late as 1992. The western pit was first used as a general municipal waste 1- 1 ( ( c . . Area Table I - 1 Solid Waste Volume Estimate Solid Waste Volume Eastern Gun Pit Over Bunker Western Gun Pit Total 3,195 C. Y. 2,228 C. Y. 6.551 C. Y. 11,974 C. Y. There are, however, some metal items commingled with the non-metal material as well as lying on the ground surface opposite the Metal Dump from the two trenches. Non-metal items existing in the trenches include wood, plastic, rubber and possibly some household waste. No hazardous waste is known to have been deposited anywhere at the Metal Dump site. The configuration of the gun pit containing the Metal Dump is consistent with other gun pits located on Fisher's Island. The east, south and west sides of the pit, as well as the floor, are constructed of reinforced concrete with the north side open. The gun pit is excavated from a small hill running approximately east to west with the open northern side coinciding with the northern slope of the hill. Between the two gun pits is a reinforced concrete bunker which was likely designed as a powder and projectile magazine for the guns. The bunker is an extremely heavily-constructed structure with a reinforced vaulted concrete roof and heavy internal concrete walls fonning a labyrinth of rooms. The two excavated trenches reside over the roof of this bunker. During operation of the Metal Dump, heavy construction equipment was used on the roof of this bunker without apparent damage. The total thickness of solid waste and cover soil on the bunker roof is estimated at eight feet. The total in-place volume of solid waste contained in the Metal Dump site is calculated at approximately 12,000 cubic yards. Observations made during the site visit indicate an approximate metal fraction of 75 percent by volume of the total waste mass. 1-3 . . B. PURPOSE OF FACILllY CLOSURE ( 1. Regulatory Issues - Landfills in New York State are regulated by the New York State Department of Environmental Conservation (DEe) under the 6NYCRR Part 360 solid waste regulations. According to Part 360, the Fisher's Island Metal Dump is, by definition, a landfill, and is therefore subject to regulation as a landfill. Part 360 contains very specific requirements for the design and construction of landfills including rigorous minimum design criteria for landfill liners in order to provide adequate long-term containment of solid waste and prevent adverse effects to groundwater. Federal regulations also contain minimum design standards for landfill liners. However, the DEC has been approved by the United States Environmental Protection Agency (EPA) to regulate landfills in New York State because the Part 360 Regulations are more stringent than federal standards. The Metal Dump was not designed as a landfill and, as such, does not meet Part 360 liner regulations. Also, no provisions have been made for the collection and treatment of leachate flowing from the site. The DEC therefore, considers the site to be an environmental risk because of the potential for damage to underlying fresh water resources from leachate generated by rainwater flowing through the waste mass. ( Recent changes in federal solid waste regulations have forced a revision of Part 360 regulations which require that any landfill operating after October 9, 1993 have a DEC-approved liner. Part 360 regulations further state that any solid waste management facility must be closed according to the minimum closure requirements for that type of facility whenever solid waste has not been received for more than one year. Closure of a landfill involves construction of a final cover system that will inhibit the intrusion of precipitation into the underlying solid waste mass, thereby minimizing the production of leachate. The Metal Dump had ceased operation long before the October 1993 deadline. However, no final cover system has been constructed and the waste within the dump remains uncovered and open to the environment. Any precipitation falling within the Metal Dump simply runs out through the open north side and onto the ground. The Metal Dump must therefore C be closed with a final cover system approved by DEC in order to be in compliance 1-4 . . ( with Part 360. Failure to comply with state regulations could result in fines levied against the Town of Southold. Before construction can begin on a landfill closure, a Landfill Closure Investigation must be performed by a Professional Engineer licensed in New York State. This investigation must include the following components: A Vector Investigation; A Landfill Gas Investigation; A Surface Leachate Investigation, and An Explosive Gas Survey ( AFinal Closure Plan must then be prepared which meets the closure requirements of Part 360. Any component of the Final Closure Plan which does not meet the minimum Part 360 design requirements requires that a variance be issued by DEC. Any variances must be applied for in the Final Closure Plan. The DEC will consider each variance in terms of its potential to provide reduced environmental protection and to effect human health. If the DEC fails to grant all requested variances, the Final Closure Plan must be modified to include design changes relative to the rejected variances. l Because of the mixture of solid wastes contained in the Metal Dump, the site is currently considered a conventional MSW landfill by the DEC and must be closed in accordance with MSW landfill regulations, Due to the unconventional nature of the site, a typical landfill final cover is impractical. Any MSW landfill cover system for the Metal Dump would require an excessive number of variances. . However, an alternate category of closure regulations within Part 360 pertain to monofills, which are landfills containing only a single specific type of solid waste, such as metal. The DEC is allowed a much greater degree of latitude when approving final cover systems for monofills, especially if the contents are inherently benign. If the Metal Dump were reclassified a monofill, a more practical closure plan could be developed which would be exactly tailored to the particular solid waste and site conditions. 1-5 . . ( ( 3. Environmental Issues - Residents of Fisher's Island obtain their fresh water from a number of private wells and from a small public water supply drawing from a freshwater pond located northeast of the Metal Dump. During a hydrogeological C study performed in 1988, a groundwater monitoring well was installed approximately Monofill closure does not require the rigorous variance approval procedure of MSW landfill closure. In order to aid municipalities with the expensive costs of landfill closure, New York State has recently initiated the Environmental Protection Fund (EPF). This fund, referenced as Title 9, Sections 54-0901 to 0911, will be established in April 1994 and will be a permanent fund renewed annually. For 1994, $30,000,000 has been allocated for this fund with $9,000,000 reserved for landfill closures. The EPF is expected to increase every year with an estimated $86,000,000 to be provided by 1997. The state will be accepting applications for grants from the EPF in May 1994. Recognized planning units such as Towns and Counties can receive up to 50 percent reimbursement for landfill closure costs. Planning units with populations over 3,500 can receive up to 75 percent reimbursement. 2. Aesthetic Issues - As previously stated, the Metal Dump is exposed to view from the top and from the north side. The metal waste contained therein protrudes from the face of the small hill that the gun pits are excavated from. The waste, being metal which is painted a variety of colors including large quantities of white, resides in a position relative to the lower road that precludes the site from becoming completely overgrown with vegetation. Furthermore, the contents of the Metal Dump are , inherently durable and resist the process of natural decay. The Metal Dump has become an eyesore for citizens of Fisher's Island residing to the north of the site because the colors and shapes of the waste contrast sharply with the closer surrounding vegetation and the view of the Atlantic Ocean further to the south. The residents of this area are therefore understandably discontented with the appearance of the Metal Dump which is visible from their properties year round and would like to see the site permanently closed and covered. 1-6 . . ( 270 feet south of the Metal Dump to monitor the effects of the Metal Dump on groundwater. During the two rounds of sampling and analysis subsequently performed on this monitoring well, no detrimental effects to groundwater were observed relative to the Metal Dump. However, exposure of the Metal Dump to the weather continuously degrades the metal and other items contained therein and leaches elements from the solid waste into the underlying water-bearing zones. New, unknown potential sources of contaminants could be activated through such mechanisms as rusting-out of fuel tanks or paint cans or leaching of lead or other metals into the groundwater. Proper closure of the Metal Dump would minimize the potential for groundwater contamination from the site, thereby effectively eliminating the environmental liability of an open dump. c Some possible solutions discussed in this study will require the initiation of a Groundwater Quality Monitoring Program by DEC as a condition of approval of the Final Closure Plan. Such a program would need to meet Part 360 regulations. At the very minimum, another two monitoring wells would need to be installed (one up- gradient and one down-gradient) in addition to the one well already residing to the south of the site. All three of these wells would be required to be sampled quarterly for at least five years. Subsequent monitoring frequency would be at the discretion of the DEC and could potentially be reduced after that time. The monitoring program would be required fora minimum 3D-year post closure period. The actual termination date of the groundwater monitoring program will be determined by DEC. Appendix A contains a rough calculation for the cost of implementation of a 3D-year groundwater monitoring program as described above, based on the actual current monitoring costs of a landfill in upstate New York. Estimates have been given both in terms of present worth and future costs with an assumed inflation rate of one percent. These cost estimates do not include the costs of well maintenance and repair or of annual reporting to DEC. The facility must be registered with DEC at the beginning of the post-closure period. This initial registration must be accomplished via a Closure and Post-Closure Registration Report submitted to DEC. The registration must then be renewed every five years until DEC determines that the post-closure period has ended. ( 1-7 . . C. PURPOSE OF THIS STUDY This Feasibility Study has been prepared in order to aid the Town of Southold in planning a reasonable, cost-effective solution to resolving or mitigating the Metal Dump issues. A number of closure alternatives are presented in Chapter II. Each alternative is described with advantages and disadvantages listed. Furthermore, cost estimates have been provided for each alternative, showing the financial impact with assumed metal fractions of 85, 75 and 65 percent by volume of the total solid waste. Analysis of this range of metal fractions results in a reasonable envelope of cost estimates, given that the exact composition of the solid waste contents are not known. Finally, Chapter III contains a discussion of a recommended plan of action towards implementing a cost-effective environmentally sound closure plan for the Metal Dump. 1-8 ( ( c ( ( (, " . . II. CLOSURE ALTERNATIVES A. REMOVAL OF ALL SOLID WASTE FROM THE SITE 1. Description - Removal of all solid waste from the Metal Dump site would return the site to its' original condition prior to deposition of any refuse. All metal and non- metal items would be removed from the site and hauled off the island, via ferry, to permitted solid waste management facilities. The largest portion of material in the Metal Dump is metal and, as such, is recyclable. During the cleanup operation, the recyclables and non-recyclables would be segregated at the site and the recyclables taken to a recycling center, most likely the one in Groton, Connecticut which currently serves Fisher's Island residents. The metal would most likely be baled at the site in order to obtain maximum density for transporting off the island. Non- recyclables would be delivered to a permitted disposal facility, probably in Connecticut. Hazardous waste is not known to have been deposited in the Metal Dump. However, should any hazardous waste be discovered during site excavation, it will be segregated from other wastes and disposed of at a permitted hazardous waste management facility in accordance with DEC and Connecticut regulations. The ultimate disposal sites for all wastes removed from the Metal Dump will be identified in the Final Closure Plan which is required to be submitted and approved by DEC prior to commencement of work at the site. Removal of the solid waste from over the roof of the ammunition bunker will involve excavation of the cover soil and may leave a depression where the material was removed from. Native soils will be obtained from a nearby borrow source and used to fill in the bunker cover soil back to its' original grade, even with the top of the gun pit walls, if required. The cover soil will then be seeded with grass and mulched. 2. Advantages - Complete removal of all solid waste is the method preferred by DEC for closure of the Metal Dump. This scenario would remove all potential contaminants from the site and eliminate any long term monitoring requirements. II-I . . The DEC, through correspondence with the Town of Southold, has endorsed this approach. During removal of the metal from Fisher's Island, a significant volume of metal would be recycled thereby generating revenues which would help offset the costs of site cleanup. Complete removal of all solid waste is a more politically acceptable solution to Fisher's Island residents. Even if completely benign wastes are likely contained in the Metal Dump, residents would still perceive the site as being a potential source of groundwater contamination. Removal of the Metal Dump contents off-island would also remove the psychological presence of a source of contamination from the minds of residents. , The fort, including the gun pit containing the Metal Dump, is a site with potential historical value. Much of the original fort property has been transferred to private owners or has been converted to other uses such as the airport and the school. Remaining fort structures have fallen into disrepair and have become overgrown with vegetation. However, should any restoration efforts be initiated at the fort, the Metal Dump gun pit and surrounding area could be restored much easier and more thoroughly with the metal contents removed. Additional funds for site closure may also be available through various historic preservation agencies if the solid waste were removed from the site. A list of such potential historical organizations is contained in Appendix B. 3. Disadvantages - Removal of all solid waste from Fisher's Island is an expensive process which will require chartering of a special barge to carry the waste to the mainland. Even with revenues from the sale of recyclables, this option is the most expensive of those considered and does not provide an appreciable degree of increased environmental protection over the option to bale the metal on-site and place it in the concrete bunker, as discussed below. 11-2 ( ( c ( ( (, ,> . . 4, CQS1 - A detailed and itemized cost estimate for complete removal of all solid waste from the eastern pit of the Metal Dump site was prepared by a Connecticut contractor prior to our knowledge of the existence of the western pit. Appendix A contains cost estimates based on the contractor's estimate and expanded on a unit cost basis to include complete cleanup of the site. The estimate assumes that the contractor retains any revenues received from the sale of recyclable metals. Appendix A calculations were performed for a metal fraction of 75 percent with a corresponding non-metal fraction of 25 percent. Calculations for metal fractions of 85. and 65 percent were also performed in a similar manner to show the cost impact based on various solid waste composition scenarios. Table II - 1 gives a summary of estimated costs for four possible project scenarios, labeled A through D, which corresponds to sections A through D of this chapter. The solid waste volume estimate is based on a computer analysis of topographical data obtained from a survey conducted in February 1994, and on information obtained from interviews with knowledgeable residents involved in the operation of the Metal Dump and on reasonable estimates of the extent of the gun pits. Line items have been added for construction supervision and engineering certification of the completed project. It should be noted that the cost estimates presented in Table II - 1 assume no hazardous waste disposal will be required. Inspection of Table II - 1, Scenario A indicated that project closure costs are very sensitive to the amount of non-metal waste within the metal dump. For example, at an assumed non-metal content of 15%, the total project cost is approximately $167,000. However, if the non-metal fraction increases to 35%, the project cost is nearly doubled to $317,000. The reason for this major cost impact is that the non- metal unit cost for disposal is approximately 13 times greater than the metal unit disposal cost. 11-3 TABLE II - 1 COST ESTIMATE SUMMARY SCENARIO A - COMPLETE REMOVAL OF SOLID WASTE, ENTIRE SITE ESTIMATED ESTIMATED ESTIMATED ESTIMATED SUB-TOTAL ESTIMATED TOTAL METAL NON-METAL METAL COST NON-METAL COST METAL REMOVAL NON-METAL ESTIMATED ENGINEERING & CONTINGENCY ESTIMATED FRACTION FRACTION PER C. Y. PER C. Y. COST REMOVALCOsr COST CERTIFICATION @15% COST 85% 15% 2.91 37.50 537.'89 584.375 5121.764 510.000 519.765 515l.S29 75% 25% 3.30 37.50 $37.389 5140.625 $178.014 510.000 528.202 $216.216 65% 35% 3.80 37.50 537.'89 5196.875 $234.264 510.000 536.640 5280.904 SCENARIO B - REPLACEMENT OF BALED METAL IN SITE, REMOVAL OF OTHER WASTES, ENTIRE SITE . ESTIMATED ESTIMATED ESTIMATED ESTIMATED SUB.TOTAL ESTIMATED TOTAL METAL NON-METAL METAL COST NON-METAL COST METAL REMOVAL NON-METAL ESTIMATED ENGINEERING & CONTINGENCY ESTIMATED FRACTION FRACTION PER C Y. PER C. Y. COST REMOVAL COST COST CERTIFICATION @15% cosr "85% 15% 2.58 37.50 533.164 $84.375 $J17.539 S 10,000 $19.1JI $146.670 75% 25% 2.92 37.50 $33.164 5140.625 $173.789 SlO,(X)() $27.568 $21J.357 == 65% 35% 3.37 37.50 533.164 $196.875 $230,039 SIO,CXXJ $36,006 $276.0-15 .j>. SCENARIO C - COMPLETE REMOVAL OF SOLID WASTE, EASTERN PIT ONLY ESTIMATED ESTIMATED ESTIMATED ESTIMATED SUB-TOTAL ESTIMATED TOTAL METAL NON-METAL METAL COST NON-METAL COST METAL REMOVAL NON-METAL ESTIMATED ENGINEERING & CONTINGENCY ESTIMATED FRACTION FRACfION PER C. Y. PER C. Y. COST REMOVAL COST COST CERTIFICATION @15% COST B5% 15% 2.91 37.50 58.200 $17.972 $26.172 510.000 $5.426 $-11.598 75% 25% 3.30 37.50 58.200 529.953 $38.153 510.000 57.223 555.376 65% 35% 3.80 37.50 58.200 $41.934 550.134 $10.000 $9.020 $69.155 . SCENARIO D. REPLACEMENT OF BALED METAL IN SITE, REMOVAL OF OTHER WASTES, EASTERN PIT ONL Y ESTIMATED ESTIMATED ESTIMATED ESTIMATED SUB-TOTAL ESTIMATED TOTAL METAL NON-METAL METAL COST NON-METAL COST METAL REMOVAL NON-METAL ESTIMATED ENGINEERING & CONTINGENCY ESTIMATED FRACTION FRACTION PER C. Y. PER C. Y. COST REMOVAL COST COST CERTIFICATION @15% COST 85% 15% 2.58 37.50 57.300 $17.972 $25.272 $10.000 55.291 540.563 75% 25% 2.92 37.50 57.300 529.953 537.253 510.000 57.088 554.341 65% 35% 3.37 37.50 57.'00 $41.934 549.234 510.000 58.885 56B.120 r, (\ ~ ( ( c , . . B. BALE & REPLACE METAL IN PIT, REMOVE OTHER WASTES 1. Description - Removal of all solid waste including the metal from the Metal Dump is the best method for confirming the absence of hazardous material at the site. Excavation of all material allows for complete inspection of the contents of the site. However, hauling the contents off Fisher's Island is the most expensive component of the complete removal scenario. An alternative to hauling the wastes off-island is excavation of the Metal Dump wastes, separation of any non-metal fraction and replacing only the metal back into one of the gun pits. Calculations in Appendix A indicate that insufficient storage volume exists in the subterranean concrete bunker to contain the entire metal fraction of the site without removal of some of the concrete dividers within the bunker which may be integral structural components supporting the bunker ceiling. Removal of integral bunker components could prove dangerous. Prior to placing the metal back into a structure, it would be densified into uniform-sized bales for easy placement and stacking. Non-metal items and potentially-hazardous or contaminated metal items would be removed from the island as in the complete removal scenario. The baled metal would then be placed in one of the Metal Dump gun pits for permanent storage. The densified metal would require an estimated one-fifth of the volume it now occupies in the gun pits. Once the metal was stacked in the gun pit, a cover system should potentially be constructed over it. This cover could take the form of a conventional built-up roof system or a landfill geomembrane-type cap. Alternately, the metal could simply be left open to the elements, in the rear of the pit out of view of nearby residences. 2. Advantages - This scenario would allow for complete inspection of the Metal Dump contents and separation and disposal of any non-metal items. Any potentially hazardous materials would therefore be removed from the site, eliminating the potential for contamination of the groundwater. 11-5 . . The resultant solid waste contained in the Metal Dump would be all metal. The DEC could therefore be petitioned to reclassify the site as a monofill. The Part 360 regulations for a monofill are significantly less stringent than those for a conventional landfill and the DEC is given more freedom with respect to reduced design and closure requirements. The variance process could be greatly streamlined and significantly less costly if this reclassification effort were successful for this unconventional closure. The costs of removal of the metal fraction from Fisher's Island would be avoided. 3. Disadvantages - Although the potential for organic contamination of groundwater will have been greatly-minimized, it is questionable whether the DEC would approve this closure method without requiring some type of long-term groundwater monitoring. Such monitoring is expensive and is typically performed at least quarterly during the initial five-year post-closure period. Because all solid waste will not have been removed from the site, a very small potential exists for the DEC to require removal of the remaining metal due to future changes in the solid waste regulations. This scenario will likely be less acceptable by some residents due to the perception that any remaining solid waste, including segregated and baled metal, may still pose an environmental threat. 4. CQS1 - Table II-I contains a cost estimate for removal, baling and replacement of the metal fraction based on the contractor's estimate cited in Section I1.A4. The costs of long-term groundwater monitoring, if required by DEC, will need to be added to this estimate to give a comprehensive cost analysis. Furthermore, the cost of a cover system, if used, would have to be added to the cost of the project. The actual cost of the cover system would depend on the type of cover which would be acceptable to the DEe. (See Appendix A) 11-6 ( ( c ( ( 3. c . . Inspection of Table II - 1, Scenario B indicates that the potential cost savings of Scenario B when compared to Scenario A are minimal. The reason for this is that the cost savings of barging the baled metal off island are largely offset by the foregone value of this metal as a recycled commodity. When one considers the potential additional costs associated with long-term groundwater monitoring and final cover systems, it seems likely that Scenario B will be more costly than Scenario A c. REMOVAL OF ALL SOLID WASTE FROM THE EASTERN PIT 1. Description - Removal of all solid waste from the eastern pit would close only that part of the site which is visible from nearby residences. The eastern pit would be completely emptied and the contents, both metal and non-metal, removed from Fisher's Island. The western pit would remain essentially untouched except for removal of the more obvious metal protruding from the northern face of the hill. Cover soil would be placed over the edge of solid waste at the interface with the waste to remain in place. 2. Advantages - An obvious cost advantage would be realized by cleanup of only a fraction of the site. Cost savings are realized from removal of reduced volumes of both metal and non-metal items. This is a significant factor since the eastern pit is only one third of the estimated capacity of the western pit. This scenario would mitigate the residential problem of site aesthetics with respect to nearby neighbors who have complained of the site appearance. Solid waste would no longer be visible from the houses located to the north. Any hazardous waste discovered during pit excavation could be segregated from other wastes and disposed of properly. Disadvantages - Potential environmental liabilities would not be eliminated from the site. They would be substantially reduced; however, wastes remaining in the western pit could still potentially adversely effect area groundwater resources. 11-7 . . This scenario would only result in the removal of approximately one-fourth of the solid waste from the site and, as such, would not be an environmentally acceptable solution to some residents. ( Any Final Closure Plan which does not address all solid waste at the site would likely result in a long-term environmental monitoring program being required by DEe. 4. ~ - Calculations indicate that the eastern pit contains roughly one-fourth of the solid waste contained in the site. As shown in Table II - 1, the cost for cleanup of the eastern pit (Scenario C) is approximately one-fourth that for the entire site (Scenario A), indicating that savings are proportional to the quantity of solid waste remaining at the site. The costs of groundwater monitoring for a potential 30-year post closure period would likely need to be added to this estimate. D. BALE & PLACE METAL FROM EASTERN PIT INTO BUNKER, REMOVE OTHER WASTES ( 1. Description - All metal and non-metal items would be removed from the eastern pit and the metal fraction baled and placed in the subterranean bunker for permanent storage. Appendix A contains calculations that indicate sufficient volume exists in the tunnel connecting the two pits and in the adjoining chamber to contain the baled metal from the eastern pit so long as the metal fraction is 75 percent or less. Storage potential of the bunker complex is limited to these two chambers due to restricted height and width of the entrance doors to other chambers. As with other scenarios, non-metal items would be removed from the island. 2. Advantages - The same advantages apply for this scenario as do for the scenario described in the previous section where all solid waste was removed from the site. The reason for this is that the bunker complex, with its massive concrete walls, roof and floor, provides adequate environmental protection for storing baled metal waste. A minor cost savings would be realized through placing the metal fraction in the c II - 8 ( ( C' .. . . bunker instead of hauling it off of Fisher's Island, when one compares the costs of Scenario D with Scenario C. 3. Disadvantages - In addition to the disadvantages described in the previous section, additional liability would be incurred by the Town relative to the metal waste which would not be removed from the site. In light of the large quantity of mixed waste remaining in the western pit, this is considered a minor impact. Access to the more remote chambers of the bunker complex would be blocked by the metal bales stored in the outer chamber. This scenario again would only result in the removal of approximately one-fourth of the solid waste from the site and, as such, may not be an environmentally acceptable solution to some residents. 4. Cost - A small cost advantage is 'obtained through avoided hauling costs of the metal fraction, as shown in. Table II - 1. Again, the costs of a minimum 30-year post closure groundwater monitoring program may need to be added to this estimate. If such monitoring is required, the cost benefits of Scenario D are probably non-existent when compared to hauling the metal off island per Scenario C. E. INSTALLATION OF FINAL COVER WITH SOLID WASTE IN PLACE OVER THE EASTERN PIT 1. Description - Closure of the Metal Dump site without removal of any solid waste will require construction of some type of final cover system over the eastern pit. This cover system would likely involve the construction of a concrete block or poured wall along the northern, open side of the eastern gun pits to form a fourth wall. Some type of cover would then need to be constructed over the solid waste, tying into the new, northern wall. The most cost-effective cover system would be a conventional, built up peak-type roof system, similar to that of a building. The final cover system design is based on pre-engineered clear span wood trusses with lateral wood purlins 11-9 . . and standing seam aluminum roof panels anchored on a treated wood sill plate. The roof also has enclosed continuously-vented soffits and ridge vents. The sill plates ( would anchor to the top of each of the gun pit walls. Solid waste surrounding the roof footprint would need to be regraded to expose all of the pit walls and to provide drainage away from the pit after the roof was constructed. This type of cover system is feasible for the eastern gun pit because sufficient volume remains in the pit to contain regraded waste materials from the periphery of the roof system. Covering the entire site with a roof-type final cover system is not practical because of the large quantity of solid waste residing outside of the walls of the western pit and on the roof of the concrete bunker. These areas, therefore, would not be covered in this type of closure approach. The interface with the edge of solid waste not covered would receive a soil cover and be seeded with grass and mulched. A leachate collection and removal system as well as long term groundwater monitoring will likely also be required for this alternative. The leachate collection system would likely d.ischarge to an underground leachate storage tank which would require periodic pumping. ( 2. Advantages - Capping of the eastern gun pit with the solid waste in place would preclude both the need for a metal baler to be brought to the site and the need to haul any solid waste to the mainland. This would eliminate the need for a specialized contractor to bale and remove the waste. Hence, the closure construction without removal of solid waste from the site could conceivably be accomplished by one of the local general contractors now residing on Fisher's Island. Capping the existing eastern pit without removing the solid waste will ensure that the site does not become a safety hazard for children who might be playing in the vicinity of the site and accidentally fall into the open pit. 3. Disadvantages - Closure of the site with the solid waste left in place would require the development and implementation of a long-term (30 year minimum) groundwater c II - 10 . . ( quality monitoring program. This program would likely require the installation of additional groundwater monitoring wells which would have to be sampled and analyzed quarterly for at least five years with reduced monitoring intervals for the remainder of the post-closure period. This monitoring program will require a significant financial commitment by the Town, including funds for well installation and well sampling and analysis. The potential liability of the continued presence of solid waste still exists at the site with the potential to someday adversely impact groundwater. By choosing to leave the solid waste in place, the Town will be financially responsible for mitigation of any future groundwater or surface water contamination caused by the Metal Dump. ( DEC will probably require that any closure plan which does not involve removal of at least the putrescible wastes contain a leachate collection and storage system. Such a system would likely require periodic emptying of a leachate storage tank and subsequent disposal at an approved wastewater treatment plant. Closure of the site with the solid waste left in place will likely show a short-term financial advantage over either of the other four scenarios described previously. However, the additional financial responsibility incurred through future groundwater monitoring and leachate management programs as well as maintenance of the cover system may be more costly to the Town if a 3D-year post-closure plan is mandated by DEe. 4. Costs - Engineer's cost estimates for final cover construction and quarterly groundwater monitoring are included in Appendix A. The pre-engineered wood and metal roof system described previously is more cost effective than a conventional asphalt shingle roof both in terms of initial cost and future maintenance. c II-ll . . ( III. RECOMMENDED CLOSURE ALTERNATIVE The recommended approach to closure of the Fishers Island Metal Dump includes consultation with DEC to arrive at a negotiated agreement which would satisfy the state's concerns regarding potential contamination of groundwater while relieving the Town of the responsibility of long-term groundwater monitoring. This would require a meeting or series of meetings between DEC, the Town of Southold and Fagan Engineers to determine the minimum scope of work acceptable to the state and town. The Landfill Closure Investigation may be required prior to reaching a final agreement. Upon reaching an agreement, development of a Final Closure Plan would proceed in accordance with this agreement. During Final Closure Plan development, Fagan Engineers should investigate alternate sources of funding including the New York State Environmental Protection Fund and Historical Preservation Services, if applicable. The Town should also take immediate steps to properly register the site with DEC, including development of a Closure and Post- Closure Registration Report. { After the Final Closure Plan is approved by DEC, the Town should implement the provisions of the Plan by soliciting bids from contractors. Fagan Engineers could prepare bid specifications to include in the bid packages by the Town. If an alternative is chosen which requires removal, .segregation and baling of the metal waste, contractors on the mainland should be contacted. Environmental Maintenance Metal Processors of Waterbury, Connecticut, have been extremely helpful in preparation of cost estimates for this project and have requested that their quotes not be divulged by the Town. This company is known to have the resources and expertise to accomplish complete site clean-up. c Upon completion of the project, Fagan Engineers should prepare a Construction Certification Report for submittal to DEC. This report is required for any landfill project and must be approved by DEC before the project is considered complete. III. 1