By Craig N. Musselman, Kenneth H. Ryder, and Dennis Slate
Musselman is a professional engineer and president of CMA Engineers, Inc. (Portsmouth, N.H.). Ryder is director of public works for the city of Lebanon, N.H. Slate is the state director of USDA-APHIS, wildlife services, in Concord, N.H.
Lebanon Regional Landfill
The city of Lebanon, N.H., has owned and operated a regional landfill for the disposal of solid waste generated by New Hampshire and Vermont municipalities in the Connecticut River Valley since the 1930s. The landfill operated as a 19-acre unlined landfill until 1993. In 1991, the city obtained state regulatory permits -- prior to the promulgation of federal standards under Subtitle D of the Federal Resource Conservation and Recovery Act (RCRA) and state solid waste rules adopted by the New Hampshire Department of Environmental Services (NHDES), both of which were promulgated later in 1991 -- to add capacity. The permits at that time allowed for the construction of 10 acres of lined landfill space, providing a total of about seven years additional capacity for the region's waste disposal needs.
The city constructed a portion of that permitted capacity in 1992. In 1995, the city requested approval from NHDES to construct the balance of the permitted capacity to provide an additional five years of capacity. At that time, a permit condition was placed by NHDES to the effect that the city needed to document full compliance with all applicable provisions of RCRA Subtitle D prior to bringing the remaining capacity into operation.
In 1995, the city also began planning for an expansion of 15 acres of lined footprint, providing an additional 25 years of disposal capacity.
The landfill receives about 35,000 tpy of municipal solid waste (MSW). Users paid a competitive tipping fee -- $48 per ton in 1997. Deliveries to the site are from private haulers and from MSW transfer stations. Deliveries from Lebanon residents are made to a transfer station with consolidated loads delivered into the landfill site. The landfill is operated conventionally with a limited working face. On-site sand, and alternative waste materials, are used for daily cover. Leachate collected is pumped without pretreatment directly to the city's sewer system.
Like most landfills without aggressive bird control measures in place, the Lebanon landfill had attracted birds throughout its operation. The site is about equidistant from the Atlantic Ocean and Lake Champlain and seasonally has attracted migrating gulls. Three species of gulls are generally found in the region: great black-backed gulls; herring gulls; and ring-billed gulls. Peak populations are generally observed in the period from October through mid-December, or later, depending upon the winter weather. The gulls are largely absent in Lebanon from late spring through the end of summer. Other birds frequent the site as well, including starlings, crows, blackbirds, and turkey vultures, but in lesser numbers. Gull populations at the Lebanon landfill have been noted to steadily increase over the years.
Over a period of several years, a local ornithologist, Dr. Peter Hunt observed that gulls would generally "forage and loaf" at the landfill during the day and shuttle between the landfill and various nearby water bodies including the Connecticut River and Mascoma Lake, located several miles east of the landfill site. The birds' path between Mascoma Lake and the landfill is over the airport. Bird counts were made four times at the landfill site in the late fall of 1994 and early winter of 1995, indicating populations of 375 to 500 gulls.
The gull population at the Lebanon landfill is small in comparison to most uncontrolled New England MSW landfills.
Lebanon Regional Airport
The Lebanon Regional Airport is located about one mile east of the landfill site and began operations in the 1940s. The facility provides scheduled commercial airline service and general aviation services to the Connecticut River Valley region. The airport is about 200 feet higher than the landfill. Although total operations (takeoffs and landings) have been declining in recent years, total passenger emplanements have been increasing steadily for more than 20 years, and are now about at 50,000 per year, an average of about 140 per day. About 40% of the traffic at the Lebanon airport is by turbine-powered aircraft, with about 60% by piston-powered aircraft.
The Lebanon airport maintains two runways, one oriented in approximately an east-west directionand the other in a north-south direction. The use of the two runways is varied based on wind and other weather conditions. The approach to the airport from the west, over the landfill site, is used infrequently, estimated to be about 1% of landings by Federal Aviation Administration (FAA, Washington, D.C.) staff at the Lebanon Airport. Takeoffs by runway are roughly evenly distributed over time, with about 25% of takeoffs estimated to be in the direction of the landfill site.
Of the 63,000 total takeoffs and landings at the Lebanon Airport, about 8,000 are estimated to occur in the direction of the landfill.
Bird strikes have not been a frequent occurrence at the Lebanon Airport. From 1989 through 1995, two gull strikes were reported involving aircraft. Both were propeller strikes with no damage to the aircraft. Like at most airports, the Lebanon Airport staff conducts a program to assure that wildlife do not interfere with aviation. Pyrotechnic scare devices are used to harass birds, and gulls are periodically killed under the provisions of a depredation permit issued to the city by the U.S. Fish and Wildlife Service (Region 5, Hadley, Mass.).
Birds and aircraft safety
Wildlife strikes to aircraft pose a significant economic and safety problem in the U.S. A recent FAA report presented a summary of data on wildlife strikes for the period 1992 through 1996. This report presented an estimate that those wildlife strikes resulted in a total of more than 80,000 hours per year of aircraft downtime and $43 million/year in direct monetary losses resulting from repair costs and lost revenues.
More than one half of bird strikes occurred on the ground or within the first 100 feet above the ground. About 80% of bird strikes occur at altitudes of 1,000 feet or less, and the balance occur at altitudes between 1,000 and 8,000 feet.
While most gull strikes do not result in damage to aircraft, the occurrence of gull strikes that cause damage is still significant. Although aircraft are less at risk from bird strikes than has been the case in the past, the fact remains that birds affecting an aircraft in the wrong way can cause significant damage or a crash. Controlling wildlife strikes of all kinds, including those potentially resulting from the attraction of gulls to landfills, is important in maintaining aircraft safety.
Obtaining regulatory permits for the construction and operation of a solid waste landfill near an airport brings into play a variety of regulatory constraints. Typically, these constraints -- whether on a federal or state level -- have been vaguely specified, and little or no guidance has been available from regulatory agencies.
Despite this, the city of Lebanon, N.H., was successful in its attempt to obtain regulatory approvals to continue operations at, and expand, an existing small lined regional landfill located about 5,000 feet from a small regional airport. The city owns both the landfill and airport, and consequently there were no competing interests -- the two facilities have actually coexisted at their present locations for more than 40 years.
The key to receiving the required regulatory approvals for the expansion was the city's commitment to, and implementation of, a bird control plan. The plan was critical to maintain the population of birds, primarily gulls, at the landfill site at a negligible level, so that no significant threat to air traffic safety exists due to the presence of the landfill.
The FAA has no regulations that directly impact upon the siting or operation of landfills. FAA Order No. 5200.5A, which was revised in 1990 from an original order in 1974, presents the FAA policy regarding waste disposal sites near airports. The order was issued following a 1973 crash in Georgia that killed seven people and was attributed to engines ingesting small blackbirds that had been attracted to the area by a disposal site.
The policy has remained in place to the present. It indicates that landfills within 10,000 feet of an airport runway for turbine-powered craft or 5,000 feet for piston-powered craft should not be allowed to operate. Landfills located further from airports must be properly supervised to insure compatibility with the airport. The order recognizes the fact that the FAA does not have regulatory authority over landfills, pointing out that landfills are regulated by the U.S. EPA and by state regulatory agencies.
As for Subtitle D of RCRA, the provisions that are applicable to the siting and operation of landfills in the vicinity of airports were promulgated in October 1991 and are found in Subpart B, Location Restrictions, Section 258.10, Airport Safety, and Section 258.16, Closure of Existing Municipal Solid Waste Landfill Units.
Section 258.10 requires that the owner or operator of any landfill located within 10,000 feet of a runway used by turbine-powered aircraft, or 5,000 feet of a runway used by piston-powered aircraft, must demonstrate that the landfill is designed and operated so that the landfill does not pose a bird hazard to aircraft. A bird hazard is defined as an increase in the likelihood of bird/aircraft collisions that may cause damage to the aircraft or injury to its occupants. The owner or operator must place the demonstration in the operating record and so notify the state environmental regulatory agency. This section also requires that new and existing landfills located within 5 miles of an airport notify the airport and the regional FAA office.
Section 258.16 requires that existing landfills located within 10,000 or 5,000 feet -- as the case may be -- of an airport that cannot make the demonstration required in Section 258.10 must have closed by October 9, 1996, or, if there is no available alternative disposal capacity and there is no immediate threat to human health and the environment, by October 9, 1998.
Typically, bird control activities might include a variety of noise scaring tactics, habitat modification, operating controls, and, typically as a last resort, selective killing of birds. Killing of migratory birds including gulls and waterfowl requires a permit under the Migratory Bird Treaty Act administered by the U.S. Fish and Wildlife Service. The regulations are presented in 50 CFR Ch.1, Part 21, Subpart D, Control of Depredating Birds, and can be found in the Federal Register dated October 1, 1991. A "depredation permit" is required in order to control gulls or other migratory birds listed under the regulations. Information required to be submitted includes a long range plan for controlling birds, a description of the specific damage being caused, the species and number of migratory birds involved, documentation of the economic loss involved, a description of non-lethal control techniques used to alleviate the problem, and details of the proposed program. Once the appropriate information is provided, limited depredation permits are generally obtainable for landfills.
The New Hampshire Solid Waste Rules have two provisions pertaining to the siting and operation of landfills in the vicinity of airports. The general environmental standards require that facilities located within 10,000 and 5,000 feet respectively of an airport "shall be designed, constructed, operated and closed in a manner that minimizes the risk of attracting birds that may be hazardous to aircraft."
The landfill siting standards preclude new landfills receiving putrescible wastes from being sited 10,000 or 5,000 feet, as the case may be, from an airport. Siting a new landfill, or an expansion of an existing landfill, requires a waiver of this rule provision. With respect to the airport setback issue, NHDES has committed to enforcing the specific language in RCRA Subtitle D, Section 258.
In 1995, the city of Lebanon faced three distinct regulatory problems. In order to open bottom liner cells then under construction, the city needed to show compliance with applicable federal and state requirements regarding bird hazards to aircraft. In order to continue operating the lined landfill beyond October 1996 or 1998, the city needed to have a bird hazard demonstration on file in the operating record. In order to continue operations beyond 1999, the city needed to comply with the federal regulations and obtain a waiver of the state setback rule provision as well.
The city authorized the preparation of a bird hazard demonstration in October 1995. The document presented a bird control plan formulated to achieve over a three-year period, by October 1998, a "negligible" bird population at the landfill.
The bird control plan, prepared by Dr. David Capen of the University of Vermont, and Dr. Hunt, included on-going monitoring of bird populations at the landfill, vegetative modifications to the habitat at the landfill to minimize loafing areas, aggressive landfill cover practices, the use of noise scaring devices, the installation of monofilament lines in areas adjacent to the active face of the landfill, and as a last resort, the selective use of lethal methods. The bird hazard demonstration was prepared in a four-week period.
The next step in the process involved applying for a waiver of the State of New Hampshire exclusion on expanding existing landfills in the vicinity of airports. Simultaneously, the city requested a waiver of the airport setback siting requirement for the proposed lined landfill expansion. The city submitted the waiver application in May 1997.
In July 1997, NHDES scheduled a public hearing and subsequently requested and received additional information about the project. In September, NHDES granted a waiver with conditions, which included requirements that the bird control plan be implemented over the life of the landfill, that monitoring and bird count data be taken over the life of the facility, and that corrective action be implemented whenever a bird hazard is determined to exist in the future.
The city also cleared another hurdle. In May 1997, the city applied for and received a depredation permit for the landfill site. The city has held such a permit for years for the airport, allowing airport personnel to shoot migratory birds as required to maintain air safety. The city's application to the Fish and Wildlife Service requested approval to kill gulls and turkey vultures after non-lethal methods were determined to be ineffective and without limits on the number of birds taken. The agency issued a permit to take gulls only and placed a limitation of 100 birds per calendar year.
The city has completed its second year of bird control activities. The first year (1996/1997) was carried out by existing landfill staff members. The city had intended to hire an additional operating staff member dedicated solely to bird control and other site clean-up activities, but the city could not initiate the hiring process until late in the fall season. The city decided to attempt to control bird populations with existing staff members who were otherwise fully committed to landfill operations. The city staff installed stakes with mylar streamers in areas of the lined landfill that had been brought to intermediate grades to limit gull loafing areas, and periodically used shotguns to fire shellcrackers (yielding a firecracker-like report) in an effort to frighten gulls when populations were high.
These activities were only marginally effective. Bird count data reported by Dr. Hunt indicate that in the fall/winter of 1994/1995, the number of gulls counted at Mascoma Lake, the presumed roost site for many of the gulls that forage at the Lebanon landfill, was typical of the gull counts for the previous five years. There were three gull counts taken at the Lebanon landfill in the period from November 1994 to January 1995, prior to the initiation of any bird control measures, which indicated an average of 425 gulls, with a peak count of 500 birds. No bird counts were reported at the Lebanon landfill in 1995.
In 1996/1997, during the first year of bird control activities by the city staff, gull counts at the landfill averaged 390 gulls in the period between September 15 and January 15, with a peak count of 700 gulls. During this period, gull counts at the Mascoma Lake roost site were slightly less than had been observed for similar periods in 1994/1995. The available gull count data indicate essentially no reduction in the number of gulls from the first year's bird control activities. Throughout this period of time, both gulls and turkey vultures had been observed under certain conditions to tower at high altitudes above the Lebanon landfill.
In 1997, the city decided to enter into a cooperative service agreement with the U.S. Department of Agriculture's (USDA, Washington, D.C.) Animal Plant Health Inspection Service/Animal Damage Control Program (recently renamed Wildlife Services), to implement a bird control plan for an initial one-year period from August 1997 through August 1998. The USDA staff formulated an integrated wildlife management program, hired a full-time staff member to be stationed at the Lebanon landfill, furnished pyrotechnics and other ammunition as required, trained the landfill operating staff on bird scaring tactics to be used when the wildlife specialist was not on site, and conducted a comprehensive data gathering program.
In addition to keeping records on gull counts at the landfill site, the program had three other components. The USDA and FAA were interested in determining whether the bird harassment program would increase the towering behavior of the gulls, thus potentially increasing the bird hazard to aircraft, so they arranged for the development of a protocol for studying towering behavior. Secondly, NHDES had been interested in gathering data on gull counts at nearby fast food restaurants in the plaza area near the landfill site, to confirm that the gull problem at the landfill was not simply transferred elsewhere. In addition, USDA staff prepared periodic gull counts through the fall of 1997 at a similar sized regional landfill in Keene, N.H., located about 50 miles south of the Lebanon landfill. Birds are not, and never have been, controlled at the Keene site.
The wildlife specialist stationed at the Lebanon landfill primarily used pyrotechnics to scare birds. Throughout six months of harassment, the gulls did not acclimate to the uneven screaming sound of the pyrotechnics. Gulls at the site immediately flew west, to the Connecticut River or into an adjacent valley in Vermont, each time the pyrotechnics were fired. This program was reinforced by selective killing of persistent gulls, well within the 100 per-year limit placed in the city's depredation permit.
Was it effective?
A summary of pertinent data regarding the effectiveness of the bird control plan in the fall of 1997 are presented in Table 1. Since the beginning of the USDA gull harassment efforts, the number of gulls counted at any time at the Lebanon landfill has been extremely low. The average number of gulls observed at one time in 1997 ranged from 4 in October to 12 in December. This compares to the average counts described earlier of 390 in 1996 and 425 in 1994. In 1997, while the pyrotechnics were being used, at no time were there a significant number of gulls at the Lebanon landfill.
Table 1 also indicates that the number of gulls at the Plaza Area were generally greater than the number observed at the landfill. This commercial area contains three fast food and other types of restaurants where staff and/or customers periodically feed waiting gulls. In November and December 1997, there were essentially the same small number of gulls at the fast food restaurants as there were at the landfill. The small number of gulls at the fast food restaurants is likely unrelated to the landfill harassment program.
The Keene, N.H., landfill served as a "control" site for the investigation, to provide data on the population of a nearby solid waste landfill where gulls were not being harassed. Although no earlier bird counts are available at Keene, the number of gulls observed at the Keene site in November and December 1997 was unprecedented. The Keene bird counts indicate that the counts at the Lebanon landfill would most likely have been much higher absent the bird control plan. It also may indicate that birds harassed at Lebanon might have migrated to the Keene site.
The study of the towering behavior of birds was not implemented because no birds were observed to tower above the site throughout the bird harassment program in 1997.
Specific data regarding the use of pyrotechnics at the Lebanon site is presented in Table 2. The number of times pyrotechnics are used each day decreases with time, as the gulls become less persistent. The number of pyrotechnics used per day can be used to help in estimating operating costs.
All in all, the bird control plan at the Lebanon landfill has been successful and has reduced the gull population at the site to a negligible level, similar to that found at local fast food restaurants. This is unlikely to pose a significant bird hazard to aircraft. The program will need to continue at the same level of effort -- the annual budget for the effort is about $50,000 -- for the foreseeable future.
After two years of implementing a bird control plan, the city of Lebanon learned several lessons. First, an integrated program involving the aggressive use of pyrotechnics with selective, minimized killing of birds, and appropriate site habitat modifications can be effective in reducing gull populations to a negligible level. Also, bird harassment needs to be implemented by full time, trained staff dedicated to bird control activities. Using landfill operating staff who are otherwise committed to other operating tasks did not work effectively.
An existing landfill can be safely operated within 5,000 feet of an airport with no significant increase in the risk of bird strikes, but only if an effective bird harassment program is implemented and remains in place. Experience at the Lebanon landfill indicates that gulls are not likely to create additional hazards to aircraft as a result of the use of pyrotechnics.
For landfills in the vicinity of airports, in appropriate settings where they can coexist, the cost of bird control needs to be incorporated in the project as a cost of doing business.
Last Revised 11/20/99