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Range Bayer rbayer@orednet.org P. O. Box 1467, Newport, OR 97365
20 June 2003
Don Mann
Manager
Port of Newport
600 SE Bay Boulevard
Newport, OR 97365
Dear Mr. Mann:
Re: Port of Newport moorage for commercial airboat tours in Yaquina Bay.
Although commercial airboats are new to the Oregon coast, they are not new to other areas. Elsewhere, issues about airboat noise and disturbance have resulted in airboat restrictions and airboats being banned from some areas (sections B-2 and C in the Attachment). Besides being banned from part of Fern Ridge Reservoir (section B-2), Lincoln City turned down the commercial airboat concession for Siletz Bay because of concerns about noise and disturbance ("Lincoln City Turns Down Airboat Plan for Siletz Bay" by Terry Dillman on p. A1 and A4 of 13 June 2003 Newport News-Times).
We can learn from what has happened elsewhere because that information is available to us. For example, one can search the Internet for "airboat," "airboat noise," and "airboat disturbance" and find much material. While some Internet material may represent individual's or a special interest's opinions, there is much material available from governmental agencies about airboat controversies (e.g., see minutes or testimony at public meetings, section D) or governmental restrictions placed on airboats because of their noise and disturbance (sections B-2 and C).
I have compiled some Internet and some non-Internet material about airboat issues and have included this material in the Enclosure and on a web page at:
http://www.orednet.org/~rbayer/airboat/airboat.htm (all lower case letters)
Based on what I have learned about airboats, I am writing in opposition to the proposal for the Port to give moorage to a commercial airboat concession because of three concerns.
Airboats are widely known to be noisy, and this is probably the most frequent concern (sections A-D). A sign of the noise is that airboat tours routinely give out ear plugs to passengers, and operators and passengers should wear ear protection (section A). Noise affects residents at moorages and along routes of airboats. The noise of airboats would also be annoying to other users of Yaquina Bay. Many people such as anglers, clammers, crabbers, boaters, sailboaters, and birdwatchers visit Yaquina Bay for tranquillity and to get away from the hustle, bustle, and noise of their everyday lives. Tourists who want peace and quiet may choose to avoid Yaquina Bay and go to more peaceful bays.
Airboats disturb wildlife by their noise, but, perhaps more importantly, by the ability of airboats to go into intertidal areas where other boats or other people cannot go. Wildlife can habituate to boat traffic in the Yaquina channel, but there is no place for them to go when airboats go into intertidal areas that would otherwise be undisturbed. Because of this disturbance, 1/3 of Fern Ridge Reservoir was closed to airboats (section B-2), and this disturbance has also been noted to be of concern in sections B-D. Disturbances of wildlife by boats are discussed in section E.
I am not sure of the following information, but it would be better for the Port to be sure if the commercial airboat can meet any speed or wake restrictions at moorage areas before moorage is granted rather than find out later. I do not know if the Port's South Beach Marina has a "No Wake" or 5 mph restriction. If so, the commercial airboat may not be able to meet this restriction because they may need to go faster than this to be controllable. Airboats do not have a rudder. In Yaquina Bay, it is often windy, so it is possible (though I do not know for sure) that a commercial airboat would have to be travelling at faster than 5 mph for safety reasons. In a summary in section C-4 about airboat restrictions in Louisiana:
The restriction prohibits airboat operations within half a mile of residential areas between sunset and sunrise, and restricts airboat speeds to 5 mph during the day. Residents were pleased with the rules. However, Airboat Swamp Tours owner Tommy Vanacor said he will not honor the regulation. "I will continue operating my tours, but I cannot promise that I'll idle down to 5 mph, for safety reasons." Vanacor said the unique, rudderless design of airboats necessitates higher speeds in windy conditions to keep the boat steady.
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I recognize that the Port of Newport is seeking revenue in these difficult financial times, and I wish the Port well in its search. However, I do not think that giving moorage to the commercial airboat venture is the solution. The small gain in revenue will, in my opinion, be offset by the problems that airboat disturbance will create.
Thank you for your time and consideration.
Yours,
Range Bayer
cc: Bob Jacobson, Port Commission Chair, 2225 NW Ocean View Drive, Newport, OR 97365
Attachment
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One indicator that airboats are noisy is that airboat tours routinely provide earplugs to their customers (search Google on at http://www.google.com for "airboat earplugs"). On charter boats that I have been on in Oregon, earplugs were not provided, and, in my opinion, were not necessary.
In the following entries, the estimated noise levels of airboats are discussed.
A-1. Minutes: State of North Carolina Board of Commissioners, County of
Henderson. 19 May 1999.
Source: http://www.henderson.lib.nc.us/county/minutes/990519m.html
EXCERPT: "Margaret Gibbs, 155 Carrie Lane, Fletcher, NC. Ms. Gibbs stated she was a licensed audiologist in North Carolina and also a property owner along the French Broad River. She expressed concern about the activities of the commercial airboat along the French Broad River. Ms. Gibbs had measured the noise of the airboat both with an analog and a digital sound level meter, both of which were calibrated. She had also measured the noise levels of aircrafts at the Asheville Airport because she lived very close to the airport also. As a reference she had measured the aircrafts passing over the same location from 56 to 74 dba [decibels] depending on the type of aircraft. The measurements that she had gotten from the airboat had been 102 to 104 dba. The sound level meters measure in units called decibels. A decibel scale is not linear. ... In the Henderson County Noise Ordinance, daytime noise is limited to 88 dba and the airboat was approximately sixteen times greater than this. The dba refers to the weighting scale and the weighting measures used for sound frequencies in the five hundred to ten thousand hertz ranges. This is the range where the human ear is the most sensitive. Ms. Gibbs distributed information that showed some everyday sound levels. Normal conversation speech from five feet away is around 55 dba. The beginning of OSHA regulations start at 85 dba, a chain saw is 100 dba and a helicopter is 105 dba. Ms. Gibbs read a few excerpts concerning OSHA regulations for businesses. All continuous, intermittent, and impulsive noise between 80 and 130 dba must be included in the exposure assessment which meant it had to be documented. Employers must offer hearing protectors to workers exposed to above 85 dba and all must be given a variety of protectors from which to choose. Training sessions must be given at least annually to workers exposed to above the 85 dba. Employers must provide base line audiograms within the first year of an employee's exposure to 85 dba and above and annual audiograms thereafter. OSHA has regulations to protect employees so was it right for people living along the French Broad River to be exposed to these levels at even higher levels addressed by OSHA without their consent or without compensation. No hearing protection is provided to all those people on the riverbank. ... Commissioner Moyer asked Ms. Gibbs where she took her audiology measurements. Ms. Gibbs replied she took them from her property along the French Broad River in a field close to the river."
[My comments about her testimony. The distance between the airboat and where she measured the sound level is not given but is important because the sound level is reduced with distance. Nonetheless, her testimony shows that sound levels of the commercial airboat were 102-104 decibels as measured on her property, which was at an unreported distance from the commercial airboat.]
A-2. Evaluation of Occupational Noise Exposures to Airboat Based Aquatic
Herbicide Applicators by R. Maglievaz, Volusia County Health Department,
DeLand, Florida. Paper 263 in Noise, Hearing Conservation and Non-
ionizing Radiation of 2001 Abstracts of the American Industrial Hygiene
Association (AIHE).
Source: http://www.aiha.org/abs01/01nois.html
EXCERPT. There is an industry recognition that airboats pose a noise hazard. During normal herbicide application activities, the airboat engine and propeller, not the application equipment, is the primary source of noise. Sound pressure levels increase with increasing engine and propeller RPM. Measurements indicate that the wood propeller offers an engineering control advantage over the carbon fiber propeller by shifting its energy to a portion of the noise spectrum to which the ear is less sensitive. The research found the use of aircraft engines to offer an engineering control advantage over automotive engines because they provide maximal thrust at minimal engine RPM. The dosimetry tests reveal the daily noise exposures of aquatic herbicide applicators to vary between 94 and 106 dBA. The use of earmuffs and earplugs is effective protection only when used in combination. It is therefore recommended that airboat operators and passengers wear both types of protection at all times.
A-3. Marion County Mulling Over Noise Ordinance for Airboats by Associated Press in 8 October 2002 Naples Daily News (Naples, Florida newspaper). Source: http://www.naplesnews.com/02/10/florida/d827939a.htm
According to University of Florida researchers an unmuffled airboat registers between 115 and 130 decibels. Most of the noise is by the propeller, so muffling the engine will not help.
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Oregon Revised Statute (ORS) 498.006 (2001 Edition; http://www.leg.state.or.us/ors/498.html) applies to airboat operators, although airboats are not specifically mentioned. It states:
"Chasing or harassing wildlife prohibited. Except as the State Fish and Wildlife Commission by rule may provide otherwise, no person shall chase, harass, molest, worry or disturb any wildlife except while engaged in lawfully angling for, hunting or trapping such wildlife. [1973 c.723 '74]"
Personal watercraft, like airboats, can go into shallow waters, and personal watercraft can disturb wildlife. Accordingly, the disturbance of wildlife by personal watercraft has been specifically prohibited in Oregon Administrative Rule 250-021-0030 (http://arcweb.sos.state.or.us/rules/OARS_200/OAR_250/250_021.html), which states, in part:
"(15) No person shall chase, harass, molest, worry or disturb any wildlife with a personal watercraft except while engaged in lawfully angling for, hunting or trapping such wildlife (ORS 498.006)."
Airboats have already been restricted from some areas in Oregon because of concerns about their effects on wildlife and emergent vegetation.
Marine Board To Meet Feb. 17. Oregon State Marine Board 4 February 2000 News Release.
Source: http://www.boatoregon.com/News/2000Archive/2-4BoardMtg.htm
The part of this News Release that is related to airboats:
[Item] "5. Request for Rulemaking - Fern Ridge Reservoir: US Army Corps of Engineers and the Oregon Department of Fish and Wildlife (ODFW) are requesting that motorized water craft, except those using small electric motors, be prohibited on any portion of Fern Ridge Lake south of Hwy. 126. The request would also prohibit use of airboats and hovercraft within emergent vegetation zones. The goal of the request is to protect nesting waterfowl and other wildlife as well as sensitive habitats. This is a request to begin rulemaking - no regulations will be adopted at this meeting."
New Boating Regulations Approved. Oregon State Marine Board 23 June 2000
News Release.
Source: http://www.boatoregon.com/News/2000Archive/6-23BoardMtg.htm
The part of this News Release that is related to airboats:
"A regulation change on Fern Ridge Reservoir in Lane County will affect two unique type of watercraft by closing about 1/3 of the lake's surface area to their use. The Army Corps of Engineers and Oregon Department of Fish and Wildlife jointly requested that air boats - boats which us an airplane-type propeller for propulsion - and non-displacement hull hover craft - craft which hover on a cushion of air - be prohibited from areas of the lake containing emergent vegetation. These marshy areas are not accessible by most other types of boats and provide habitat for waterfowl and other wildlife, especially during nesting seasons.
"The new regulation prohibits airboat and hovercraft operation on 3,195 acres of the 9,360 acre lake. Areas affected include Coyote Creek, Amazon Bay, South Marsh and the Long Tom Area."
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Interior Alaska Airboat Assoc. Inc. vs. State Board of Game (3/2/01) sp-5369 in the Supreme Court of the State of Alaska. 2 March 2001. Source: http://www.touchngo.com/sp/html/sp-5369.htm
The Alaska Board of Game closed the Nenana Controlled Use Area (CUA)
to airboats for hunting moose "to forestall habitat alteration and
eliminate conflicts between moose hunters who use airboats and moose
hunters who use other means of transportation." Part of the lawsuit was
also about the Noatak Controlled Unit Area where the Alaska Board of Game
closed a corridor to the use of aircraft for hunting during part of the
hunting season.
The court's findings of fact and conclusions of law particularly
relevant to this appeal for the Nenana Controlled Use Area:
"1. The Board of Game heard testimony from members of the public in an area of the Tanana Flats near Nenana, Alaska, [of] airboat use by moose hunters interfering with traditional spot and stalk and stillhunting techniques used by subsistence moose hunters.
"2. The Board of Game also heard testimony that in the same area, where heavy airboat use had occurred, some wildlife habitat changes, including alterations of drainage patterns, had been observed.
"3. The Board of Game also heard testimony that airboat noise can range up to 135 decibels, approximately the same as the noise produced by the engine of a commercial jet aircraft being operat[ed] under full power, and that it was impossible for hunters to hear or call moose in the vicinity of such noise.
"4. The Board of Game also heard from airboat users and manufacturers, who testified that technological advances were addressing the noise problem, and who countered the habitat damage testimony and various other complaints raised by others about airboat use.
"5. The Board of Game concluded that a conflict existed between moose hunters using airboats and moose hunters using the more traditional spot and stalk and stillhunting methods, and that this conflict detrimentally affected the subsistence use of moose from the area, although game levels remain stable.
From Footnote 24 of the decision: The Alaska Board of Game "... noted that 'large areas near Fairbanks remain open to airboat use for moose hunting.' Further, the Board stated that 'an area of comparable habitat, size and accessibility remains available to airboat hunters in adjacent areas of GMU 20A and GMU 20C. This adjacent area has traditionally been less important for subsistence hunters and more frequently used by airboat hunters than has the NCUA [Nenana Controlled Unit Area]."
Although moose hunters could still use airboats in some areas, the airboat association wanted access to all areas.
The Supreme Court entered final judgment dismissing the complaint of the Interior Alaska Airboat Association. Inc., so the Alaska Board of Game could exclude airboats used for hunting during the hunting season from some areas.
17. Outdoor Recreation in U.S. Army. Integrated Natural Resource
Management Plan, 1998-2003, for Fort Wainwright, Alaska.
Sources:
http://www.usarak.army.mil/conservation/images/wainwebpdf/19fwainch17.pdf
http://www.usarak.army.mil/conservation/fw_inrmp_old.htm
The following is from p. 152 of Chapter 17; the Army classed airboats as ORV's:
"Airboat operation in TFTA [Tanana Flats Training Area] is controversial. In 1988, the Army, concerned over damage by airboats in TFTA, restricted airboats to main river and stream channels in 6th Infantry Division Regulation 420-6, Management of Hunting, Trapping, and Fishing on Army Lands in Alaska. The Interior Alaska Airboat Association retained counsel, and requested reconsideration of restrictions, based on discrimination against airboat operators [footnote 21]. The Commander, after additional involvement on the part of individuals within the Airboat Association and the Alaska Congressional Delegation, rescinded restrictions on airboats, pending review of environmental considerations and recreational use.
"A study on environmental impacts of airboats on TFTA was conducted by CRREL (Racine, et al., 1990). Airboats were found to damage floating vegetation and affect trumpeter swan distribution.
"A 1991 memorandum [footnote 22] summarized the issue. This action memorandum recommended: limiting airboats to the primary use area established before 1985, preparing an environmental assessment on the use of ORVs on Tanana Flats, making a decision on the use of airboats on TFTA, preparing an ORV Management Plan if airboats are allowed, and enforcing the decision.
"Initial studies in 1989, showed that airboats increase water flow in Tanana Flats by opening waterways, but that this was probably not significant. Beaver damming activity helps offset this increased water flow (Racine, et al., 1990). Since then, airboat traffic has increased, and the significance of airboats opening waterways may have increased as well. Airboats damage or destroy beaver dams. There also is concern about effects of airboat traffic on waterfowl distribution. ADF&G [Alaska Department of Fish and Game] is concerned about airboats, including effects on wetland hydrology and game harvest by hunters. In 1996, the area west of Wood River was closed to airboats by ADF&G. This action will increase the demand by airboat users for use of TFTA."
What is a Motorized Personal Watercraft? Monterey Bay National Marine
Sanctuary.
Source: http://www.mbnms.nos.noaa.gov/visitor/craft.html
Motorized Personal Watercraft in this National Marine Sanctuary includes airboats, and this document states: "To help protect Sanctuary habitats and sensitive marine life, it is unlawful for any person to operate motorized personal watercraft except within four designated zones and access routes within the Sanctuary.
"Watch Out For Wildlife ...Although it may be tempting to approach them [wildlife] for a closer look, please watch them from a distance. Avoid harassment (which is illegal) by staying at least 50 to 100 yards away. Harassment includes causing an animal to change its behavior. If you want to observe wildlife while riding, idle your speed to reduce wake and noise, and watch quietly from a non-threatening distance. Disturbing animals deprives them of needed rest, may interrupt or stop feeding, or force them to burn precious energy by fleeing. These impacts can weaken animals and lead to death by stress, starvation or disease."
Watercraft Regulations of Lake Winnebago, Missouri.
Source: search for "airboat" in
http://www.lakewinnebago.org/Watercraftreg.PDF
EXCERPT. "14. Airboats Prohibited: No Airboat shall be operated at any time on the Lake."
Jefferson Parish Parish Council Passes Airboat Noise Regulation by Manuel
Roig-Franzia in P. B3 of 24 April 1997 of The Times-Picayune (Jefferson
Parish, Louisiana newspaper).
Source: http://www.nonoise.org/news/1997/apr20.htm
See the 7th article on the page. SUMMARY. A new ordinance limiting airboat noise in Jefferson Parish, Louisiana, has been passed by the Parish Council. The restriction prohibits airboat operations within half a mile of residential areas between sunset and sunrise, and restricts airboat speeds to 5 mph during the day. Residents were pleased with the rules. However, Airboat Swamp Tours owner Tommy Vanacor said he will not honor the regulation. "I will continue operating my tours, but I cannot promise that I'll idle down to 5 mph, for safety reasons." Vanacor said the unique, rudderless design of airboats necessitates higher speeds in windy conditions to keep the boat steady. While councilman Lloyd Giardina argued that Florida had similar restrictions on speed, Vanacor's attorney Steve Grefer said the regulations would not stand up in court. Vanacor promises a court battle if he is given a citation.
Airboat Noise Rattles Homeowners by Jeffrey S. Solochek in 27 January
2002 St. Petersburg Times (St. Petersburg, Florida newspaper).
Source:
http://www.sptimes.com/2002/01/27/Hernando/Airboat_noise_rattles.shtml
Quote: "At least seven counties and three cities in Florida have some airboat regulations, she noted, and they deal with hours of operation, permitted areas of use, mufflers, sound levels, public safety, propeller blast, lights, launching hours and speed limits."
Florida Keys National Marine Sanctuary Regulations: Final Rule by Department of Commerce, National Oceanic and Atmospheric Administration. 15 CFR Parts 922, 929, and 937 in 32154 Federal Register Vol. 62, No. 113 Thursday, June 12, 1997 / Rules and Regulations. Source: http://www.fknms.nos.noaa.gov/regs/15cfr922.pdf
922.164 #2 on p. 32165: airboats "are prohibited within the marine portions of Great White Heron and Key West National Wildlife Refuge Management Areas described in Appendix II to this subpart."
Big Cypress National Preserve (Florida) Final Recreational Off-Road
Vehicle Management Plan, Supplemental Environmental Impact Statement.
National Park Service. 2000.
Source: http://www.nps.gov/bicy/Bicy-018.htm
Search within the document for "Criteria for Closures" and scroll down to see that areas within 1,500 feet of an "active Bald Eagle territory" are closed to Off Road Vehicles (ORV), which includes airboats; and that airboats are authorized in Zone 4 only when water levels are sufficient.
Search for "Designated Trails" and scroll down to see that airboats are not allowed in Zones 1-2 and have restricted use in Zones 3-4.
Search for "Vehicle Specifications" and see that only airboats that do not exceed 8 ft wide by 14 ft long are allowed. For noise control, airboats are required to have "one or more exhaust headers or manifolds attached to a flex pipe and routed to the rear of the boat."
Chassahowitzka National Wildlife Refuge. U.S. Fish and Wildlife Service. http://southeast.fws.gov/pubs/chasstearsheet.pdf
P. 1: airboat use is restricted to certain waters. The map on the second page shows that airboat routes are very small and that they are not allowed in most of the Refuge.
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Reading the testimony at meetings or hearings is a good way to grasp the controversy that has arisen about unrestricted airboat usage in some areas.
It would be wise to learn from the experience of others rather than waiting for the problems that have arisen elsewhere to be repeated in one's own location. After a problem has arisen, it is more difficult to deal with than if it can be "nipped in the bud."
D-1. Shiawassee National Wildlife Refuge Draft Comprehensive
Conservation Plan Summary. [U.S. Fish and Wildlife Service Shiawassee
National Wildlife Refuge, 6975 Mower Road, Saginaw, Michigan 48601]
Source:
http://midwest.fws.gov/planning/shiawassfccpsummary.htm#Refuge%20Issues
Search for "Public Use Issues," part of which states:
"Participants in open house events and focus group meetings
expressed a wide range of philosophies on public use of the
Refuge. ... The subject of airboats on rivers flowing through the
Refuge drew a strong response from people who believe that the
Refuge should provide a tranquil place to view birds. Airboat
operators were described as having 'disregard' for anglers and
wildlife observers. Comments included concerns about safety on the
river as well as the noise disturbance. Participants suggested a
variety of solutions, including instituting a no-wake zone;
expanding noise abatement codes; strictly enforcing wildlife
harassment codes; and implementing horsepower or speed
restrictions."
D-2. Minutes: State of North Carolina Board of Commissioners, County of
Henderson. 19 May 1999.
Source: http://www.henderson.lib.nc.us/county/minutes/990519m.html
Search for "French Broad River airboat situation" for the start of the Commissioner's discussion and later Public Input. An airboat guide (Mike Levins) spoke in favor of airboats. Other speakers presented their concerns that were mostly about the commercial airboat, which was larger and noisier than the Levins' airboat. Concerns included airboat wakes, airboat speed, human safety for other boaters (especially kayakers and canoers), and disturbance of wildlife.
D-3. Council Minutes: Fort Myers Beach (Florida) Town Council Meeting.
22 February 1999.
Source: http://www.fmbeach.org/minutes/1999/02_22_99.htm
Search for "Restricting Air Boats" to read about the Public Hearing about banning airboats.
Portions of the Minutes about Ilene Barnett's comments: "Ms. Barnett said [she] has worked for the county and the state (DEP) and has worked at Big Cypress and Everglades. The Marine Resources Task Force was appointed by the Town Council to deal with environmental issues. The area outside of the towns jurisdiction still has concern to them. The MRTF hasnt yet had a chance to work on a back bay management plan, but they will in the near future. They will be addressing the appropriate usage of all kinds of vessels, but the airboat issue is timely now. They do not have a lot of activity now and we can save a lot of heartache in the future if we address it now. The main environmental impact is the airboats are much louder than most other boats. The other issue is the impact to the shallow estuary system and wetlands. Most vessels except canoes and kayaks and jet skis cannot get in these shallow areas. Jet skis can do some damage, but mostly they are used in deep water. Airboats were designed to get into the marshlands. She handed out an aerial photograph of the Big Cypress Preserve. It shows scars on very shallow freshwater marches [marshes ?] from airboats. They are having a hard time shutting them out because there are so many there who are operating commercially. She also cited a study about disturbance of nesting bird colonies by the Game and Fish commission. It compared the impacts of someone walking slowly toward a nesting colony, canoeing near a nest, using a small boat with 30 hp motor, and using a 14-foot airboat. The airboat impact was much more than any of the other three. All species were affected. The minimum setback for approaching protected wading birds should be almost 1000 feet. She cited a letter from Nancy Douglas, a biologist with the Freshwater Game Commission that said that most sensitive species react at 200 meters. In Estero Bay it would be difficult to operate airboats without disturbing. There are two national wildlife refuges that have already banned airboats. She read a report that the extreme noise generated by the airboats disturbs the nesting eagles even when they are outside the preserve boundaries. The other impact is from shallow areas. She read a letter from an expert on mangroves who said that airboats form a large wake and that causes erosion and changes the sediment patterns which mangroves are very sensitive to. She read another letter that said the pressure of the airboat hulls causes compaction of fragile soils. ..."
Other speakers discussed concerns about excessive noise of airboats, human safety concerns about near-collisions of boats with airboats, disturbance of wildlife, and impact on habitat.
The City Council voted unanimously to ban airboats from their "Back Bay."
D-4. Minutes of the Meeting of the Board of County Commissioners, Brevard County, Florida. 19 May 1998. Source: http://crystalweb1.clerk.co.brevard.fl.us/minutes/m051998.htm
Search for "Regulation of Boats" and read the whole section for discussion by airboat proponents or citizens complaining about airboat noise, inappropriate speed, danger to small boats, erosion, and wildlife disturbance. Most of the complaints and concern seems to be concentrated on one commercial airboat.
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There are two kinds of airboat effects on wildlife. First, the noise of airboats. Second, airboats intrude into areas where wildlife are not otherwise disturbed.
Below are some references that I have found about airboat disturbance of wildlife and about boat disturbance of wildlife that could be applied to airboats.
Bartelt, G. A. 1987. Effects of disturbance and hunting on the behavior
of Canada Goose family groups in eastcentral Wisconsin. Journal of
Wildlife Management 51:517-522.
Airboats were observed to unintentionally disturb Canada Geese and
were also used intentionally to disturb Canada Geese families for
experimental purposes.
Jahn, L. R. and R. A. Hunt. 1964. Duck and coot ecology and management
in Wisconsin. Michigan Dept. of Natural Resources Technical Bulletin 73.
The abstract of this article by York (1994:10-11), states: "Airboats
easily invade shallow-water areas of most value to waterfowl and pose a
serious threat to waterfowl production in Wisconsin."
Linscombe, J. T., T. J. Hess, Jr.; and V. L. Wright. 1999. Effects of
seismic operations on Louisiana's nesting Bald Eagles. Proceedings
Annual Conference Southeastern Association Fish and Wildlife Agencies
53:235-242. (This is at SK1.S6) in OSU Libraries.)
In 1998 tests, eagles began flushing when an airboat approached
within 310 m (1,017 ft) of their nest, and, in 1999, eagles began
flushing when an airboat was 460 m (1,509 ft) away.
Rusch et al. 1985. Evaluation of efforts to redistribute Canada geese. Transactions North American Wildlife and Natural Resources Conference
50:506-524.
Based on an abstract in Dahlgren and Korschgen (1992:45)(see
following section), the ability of airboats to disturb wildlife was so
well-known that airboats were used intentionally as a management tool to
haze Canada geese at Horicon National Wildlife Refuge.
The following sample of references are not specifically for airboats, but airboats would be expected to have similar disturbance effects. There are many more articles than can all be listed here; for example, see reviews by Dahlgren and Korschgen (1992) and York (1994).
Bratton, S. P. 1990. Boat disturbance of Ciconiiformes in Georgia
estuaries. Colonial Waterbirds 13(2):124-128.
Using 15 and 21 ft boats travelling at an average of about 9 mph,
Bratton found that foraging wading birds began to be flushed when a boat
approached to within about 55 m (180 ft) of the birds. The flushing
distance for boats traveling faster may differ.
Dahlgren, R. B. and C. E. Korschgen. 1992. Human disturbances of
waterfowl: an annotated bibliography. U.S. Fish and Wildlife Service,
Resource Publication 188.
On p. 2, they tallied a total of 66 papers about boat disturbance of
waterfowl that are included in their bibliography; the annotated
references are listed on their p. 54.
McGarigal, K. 1988. Human-eagle interactions on the lower Columbia
River. Master of Science Thesis, Oregon State University. Corvallis,
Oregon.
This research was conducted downstream of Longview, Washington in
the Columbia River. On p. 104, it is written that buffer zones of 200 m
(656 ft) and 350 m (1,148 ft) would be required to protect 50% and 95% of
foraging Bald Eagles from being flushed by moving boats. The size,
speed, and noise level of the boats was not reported.
On p. 106, he wrote: "I recommend buffer zones 400 m (1,312 ft) wide
around high-use foraging areas as the single most appropriate and
practical management strategy."
Rodgers, J. A. and S. T. Schwikert. 2002. Buffer-zone distances to
protect foraging and loafing waterbirds from disturbance by personal
watercraft and outboard-powered boats. Conservation Biology 16(1):216-
224.
Minimum recommended buffer-zone distances between waterbirds and the
approach of personal watercraft or a 30-horse power outboard boat
directly towards waterbirds at 35-40 km/hour (22-25 mph) to prevent
flushing. Only species occurring along the Oregon coast are listed
below, and distances in feet have also been calculated and added. The
flushing distance may differ at other speeds or for airboats. -=no data
given.
---------------------------------------------------------
Personal Outboard
Watercraft Boat________
Species (m) (ft) (m) (ft)
------------------------------------------------------
Brown Pelican 183 600 147 482
Double-crested Cormorant 156 512 132 433
Great Blue Heron 145 476 133 436
Great Egret 130 427 146 479
Caspian Tern 98 322 - -
Black-bellied Plover 88 289 84 276
Willet 91 299 94 308
Short-billed Dowitcher 82 269 - -
Osprey 142 466 149 489
---------------------------------------------------------
Stalmaster, M. V. and J. L. Kaiser. 1997. Flushing responses of
wintering Bald Eagles to military activity. Journal of Wildlife
Management 61(4):1307-1313.
They studied flushing responses of wintering bald eagles to military
firing activity, helicopter overflights, and boating on the Nisqually
River and Muck Creek on the Fort Lewis Army Reservation, Washington,
during 1991-94. Sixty-one percent of 1,825 eagles flushed in response to
52 experimental boat disturbances on the Nisqually River. Subadults
flushed more often than adults, and eagles feeding or standing on the
ground flushed more often than those perching in trees. Their data
suggest that ordnance explosions, low-level helicopter overflights, and
boating should be restricted near eagle foraging areas.
Stalmaster, M. V. and J. L. Kaiser. 1998. Effects of recreational
activity on wintering Bald Eagles. Wildlife Monographs No. 137:1-46.
The effect of recreational activities on wintering bald eagles along
the Skagit River Bald Eagle Natural Area in northwest Washington was
studied. Boats coming by early in the morning were most disturbing.
Eagles that were feeding were less tolerant of humans than eagles that
were perching. With increasing numbers of disturbances, eagles took
increasingly longer to resume feeding.
Vos, D. K., R. A. Ryder, and W. D. Graul. 1985. Response of breeding
Great Blue Herons to human disturbance in northcentral Colorado.
Colonial Waterbirds 8(1):13-22.
For a 12 ft boat with a 9.5 hp outboard engine traveling at
7-10 mph, they recommended a buffer zone of 150 m (492 ft).
My comment: the buffer zone may need to be greater for an airboat
traveling faster.
[Mistakenly not included in my letter: York, D. 1994. Recreational-boating disturbances of natural communities and wildlife: an annotated bibliography. U. S. Dept. Interior, National Biological Survey, Biological Report 22. (This is QH301.U4 No. 22 at OSU Libraries.)]
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