This project is funded in part by Federal Aid to Wildlife and Sportfish Restoration.and is a publication of the RI Department of Environmental Management’s Fishand Wildlife Division. This publication is intended to provide the reader with information on the natural history of beavers, their behavior, and the ecologicalbenefits associated with them. It also provides information on techniques to minimize beaver related problems and damage control techniques.

A Guide to Their History, Behavior, and Coping With Problems AssociatedWith Their Acti t iv ies

B E A V E R SIN RHODE ISLAND

C O N T E N T S

3 Introduction «4 Natural History «5 Behavior «6 Benefits of Beaver Activity «6 Human-Beaver Conflicts «7 Rules and Regulations «7 Management «10 Selected References «10 Water Level Control Devices «11 Beaver Distribution in RI «11 Selected References «

T H E B E A V E R H A S P L AY E D A S I G N I F I C A N T R O L E I N T H E E C O L O G Y O F N O R T H E R N N O R T HA M E R I C A N E C O S Y S T E M S S I N C E T H E R E C E D I N G O F G L A C I E R S 1 0 , 0 0 0 Y E A R S A G O. By buildingdams across low gradient streams and waterways beavers created a variety of wetland types beneficialto a wide range of other wildlife. These wetlands were dynamic, constantly changing theircharacteristics over time as beavers moved into or out of an area depending on available food.

Beavers were an important resource for native North Americans, providing a source of meat, skins, andmedicine in addition to creating habitat for plant and other wildlife species important to their way oflife. Beaver pelts were traded amongst Native American communities for other commodities.

The historical role of the beaver in the exploration and development of North America is welldocumented. The bartering of beaver pelts and those of other furbearers established relationshipsbetween Native Americans and European colonists. Beaver skins were shipped to Europe to supplydemands created by European fashion trends. Trappers seeking beaver and other furbearers traveledinto the interior of the continent, often the first Europeans to view natural wonders and make contactwith native Americans.

Early settlers and native peoples harvested beaver using any means possible and in any season. Therewere no regulations limiting the amount of harvest, the method or time of year beaver could be taken.In addition to the increased and unregulated hunting and trapping pressure, land use changesassociated with colonization were taking place. The forested landscape that dominated northeasternNorth America was cleared to make way for agriculture. Wetlands were drained for planting ofagricultural crops. By the 1700’s beaver populations throughout northeastern North America haddeclined dramatically due to loss of habitat and unregulated harvest. By the early 1800’s, the beaverhad been extirpated from Rhode Island and much of New England.

A decline in agriculture that began in the late 1800’s in Rhode Island and the rest of New Englandallowed for the regeneration of forests. In addition, attitudes toward wildlife began to change, leadingto laws for the protection of wildlife and the creation of state fish and wildlife agencies. Several NewEngland states, realizing the importance of beaver in ecological and economical terms initiated beaverreintroduction programs.

In the revised edition of "Mammals of Rhode Island" published in 1968, John Cronan wrote: "…and tothis time, permanent colonies of beaver do not exist in Rhode Island." He also wrote: "Permanentcolonies of beaver do exist in nearby Connecticut and Massachusetts, and if so desired beavers couldundoubtedly be re-established in western Rhode Island. There is question, however, as to whether ornot this would be desirable in a heavily populated state such as Rhode Island." In 1976, the Division ofFish and Wildlife confirmed the first beaver colony in Rhode Island since the 1800’s. Beavers hadtraveled into Rhode Island from Connecticut in the Moosup River system. Since that time beaverpopulations in the state and elsewhere have expanded dramatically due to abundant habitat, lack ofnatural predators and modern wildlife management practices. Today, beavers are well established inProvidence, Kent and Washington counties. There are more beavers in Rhode Island today than at anytime in the last two hundred years. It is anticipated that the population will continue to increase andexpand their range until all suitable habitat is occupied.

The recovery of beaver populations in southern New England has many ecological benefits. But beaveractivity at times conflicts with human interests and activities, causing the flooding of septic systems,woodlots, agricultural land and roads. Management that considers both economic and ecologicalconcerns is key in promoting the coexistence of the beaver and humans in Rhode Island.

3

I N T R O D U C T I O N

N A T U R A L H I S T O R YDescriptionThe beaver (Castor canadensis) is a semi-aquaticmammal that is physically adapted to living in anaquatic environment. It is also the largest rodent inNorth America, weighing on average between 40and 60 pounds as adults and reaching an overalllength of 36 to 48 inches. Where plentiful, highquality food is available beaver can attain largersizes. Beavers weighing in excess of 80 poundshave been documented from other parts of NorthAmerica. The largest beaver recorded in RhodeIsland to date weighed 62 pounds. There is no sizedifference between males and females. It is impos-sible to tell a male from a female based on exter-nal appearance unless a female is lactating. Thebeaver’s flattened tail, measuring 10 to 18 inchesin length is probably it’s most recognizable charac-teristic. The tail appears scaly and is covered withshort bristly hairs. Tails are used to slap the wateras a warning signal. Beavers have large incisorteeth and their large skulls support massive jawmuscles. The front of the incisor is covered withorange-colored enamel that is much harder thanthe back edge of the incisor. This causes the backof the tooth to wear faster than the front, creatinga chiseled edge. The incisors grow continuouslythroughout the beaver’s life. Beavers have twotypes of fur, long guard hairs and a dense, softerunderfur. The underfur acts as insulation and keepswater away from the skin. Fur coloration can varyfrom yellowish brown to almost black. Large hindfeet with webbing between the toes are used topropel the animal through the water. Short frontfeet are not webbed but are equipped with largeclaws adapted for digging, carrying mud andgrasping food items. The front and back feet eachhave five toes. Beavers have poor eyesight, buthave well-developed senses of hearing and smell.The openings of the nose and ears can be closedcompletely when underwater. Beavers have spe-cially adapted folds of skin that can prevent wateror wood from entering the mouth while chewing.This allows them to chew underwater. Beavershave transparent eyelids allowing them to seeunderwater.

Life CycleAdult beavers mate for life. If one mate dies thesurviving individual will readily accept a new mate.Mating takes place between January and March,and after a 98-100 day gestation period the female

Close up of a beaver’s hind food (top), side view ofa beaver skull (middle) and close up of a beaver’stail (bottom).

Photos courtesy of Fish and Wildlife

gives birth. An average is four kits, however it mayrange from two to nine. Females have four nipples tonurse the young. The young are weaned about onemonth after birth. The young beavers will stay with theadults for two winters before becoming sexuallymature and leaving on their own or driven out by theadults to establish territories in available habitat andseek their own mates. Within a family group, only theadult pair will breed, producing one litter per year.

DietBeavers are herbivores. Diet changes seasonally, withbeavers feeding primarily on non-woody aquaticplants such as water lilies, cattails, ferns, and grassesduring the growing season. Starting in late summer,beavers consume more of the shoots, twigs, leavesand cambium of woody plants such as willows, birch,aspen, white oak, and red osier dogwood, as non-woody food becomes less available. As autumnapproaches, beavers create a cache, or stockpile ofwoody vegetation on the pond or river bottom nearthe lodge to last them through the winter months. Thisfood cache will be available to them when the pond iscovered by ice. Because their teeth grow constantly,they will chew woody material throughout the year.

B E H A V I O RBeavers are, perhaps, best known for their ability toalter the landscape around them, modifying their sur-roundings by damming low gradient streams andsmall rivers to create wetlands and ponds that main-tain a constant water level. The newly created habitatprovides the beaver with protection from landdwelling predators, access to food sources, and anarea that will not freeze to the bottom during the win-ter. Dam construction is an instinctive behavior and isbelieved to be stimulated by the sound and sensationof running water. The dams and lodges that beaver’sconstruct are made from sticks, rocks, mud, andaquatic vegetation. The beavers use their forepaws to

gather and apply mud that serves as a plaster thatholds the structure together. Beaver dams can be sev-eral feet or several hundred feet long depending onthe topography of an area. Also, an area may containmultiple dams as the beaver’s work to regulate waterlevels. Dam building activity usually peaks in thespring and fall as beaver’s work to make repairs after awinter of inactivity or in preparation of the oncomingwinter. Beavers are nocturnal meaning they are mostactive at night, but can be active during daylight aswell. Beavers do not hibernate.

Lodges are constructed within these impoundments

and consist of large mounds of mud and woody mate-

rial surrounded by water or against an embankment

usually with two underwater openings for access.

Within each lodge there is a chamber located above

the water line. This chamber is lined with mud and

plant material. The top of the lodge is loosely sealed

to allow for air circulation. Lodges can range from 10

to 40 feet across and from 3 to 6 feet in height above

the water surface. A family group, or colony, consist-

ing of a pair of monogamous adults and offspring

from one or two previous years occupies a lodge. One

family may utilize more than one lodge at a time.

When first colonizing a site beavers often excavate

dens in embankments with underwater entrances lead-

ing to living chambers above the water level. These

bank dens may extend as far as thirty feet into the

embankment. Lodges may then be built against the

embankment in future years. Beavers occupying large

lakes or rivers where water levels are relatively con-

stant often do not build dams or lodges. Beavers are

territorial, and will not tolerate other beavers within

their established territory. They mark the boundaries of

their territory with scent produced in their castor

glands. Beavers create piles of mud and vegetation on

the shoreline called castor mounds onto which castor

is deposited. These mounds can often be identified by

the sweet perfume-like odor of the castor.

5

During the 150 plus years that beavers wereabsent from Rhode Island, the human popula-tion and associated activity such as road andhome contruction increased dramatically.

Photo courtesy of Providence Journal

While beavers impose change on landscapesoften shared by humans, many aspects ofthese alterations are beneficial to both peopleand wildlife.

Wildlife habitat creationBeaver impoundments create habitat for avariety of wildlife species that are wetlanddependent, including other furbearers (otter,mink and muskrat), amphibians, reptiles, fish,insects, waterfowl, wading birds, and song-birds. Wetlands are critical to many wildlifespecies life history requirements. These areasare not only important for migrating birds butthey also serve as breeding habitat for manyspecies. Dead standing trees within beaverponds are utilized by great blue herons andwood ducks for nesting. Other waterfowl uti-lize beaver flowages for brood rearing. Habitattypes change over time as beavers occupy orabandon areas. The result is a diversity ofwetland types with different plant and animalcommunities.

Wetland creationAside from the wildlife habitat that beaveractivity produces, the habitat modificationitself is of great importance. The loss of wet-lands to development has been well docu-mented. The benefits that wetlands affordhumans are numerous. Wetlands act as natu-ral flood control areas, able to store largeamounts of water and slow the release offloodwaters, protecting land downstream.Wetlands also improve water quality becausethey generate high sedimentation rates andpromote nutrient transfer and removal.Wetlands are sights of groundwater recharge,and are a natural storage area for water thatcan be used for irrigation and fire suppres-sion. When abandoned due to scarcity of pre-ferred foods or shallow water, neglectedbeaver dams breach, draining the impound-ment and exposing a nutrient rich substrate.The previously flooded areas become mead-ows, succeeding into shrub-dominated wet-lands and eventually wetlands dominated bytrees. At all stages, these wetlands provideimportant habitat for a variety of wildlifespecies.

Economic valueHistorically, the beaver has been a valuablesource of fur and food; this value continues toproduce an economic benefit today. Fur is arenewable natural resource. Beaver pelts areused to make clothing, their glands are usedin the manufacture of perfumes and trappinglures, and in some parts of North Americabeaver meat is consumed by people and pets.

Aesthetic and Educational valueThe beaver, as a historically significant wildlifespecies, is one of the most widely recognizedanimals in North America. Beavers are awatchable wildlife species and the habitatsthey create are enjoyed by the many peoplethat fish, trap, hunt, canoe, hike and photo-graph wildlife, or who simply like to observenature. Beaver ponds are used as outdoorclassrooms to study numerous aspects ofwetland ecology.

H U M A N - B E A V E RC O N F L I C T SHabitat modifications which beavers producemay have negative impacts on public and pri-vate property, including flooding of wells, sep-tic systems, and roadways and tree damage.Increased beaver populations and subsequentincrease in nuisance complaints have createda need for selective management of beaverpopulations and for damage control meas-ures. During the 150 plus years that beaverswere absent from Rhode Island, the humanpopulation and associated activity such asroad and home construction increased dra-matically. Unfortunately, at the time that mostroadway culverts, spillways and otherdrainage systems were constructed, thepotential future conflicts with beaver activitywere not a consideration. Beaver damage issometimes perceived to be worse than it actu-ally is, such as when a floodplain of a river orstream becomes inundated, flooding low-lying timber or fields. This is more often aninconvenience than an actual threat to healthand property.

FloodingLow lying areas adjacent to watercourses andwithin the floodplain upstream of a beaverdam are susceptible to significant flooding.

B E N E F I T S O F B E A V E R A C T I V I T Y

Beavers createhabitat for a widevariety of wildlifespecies that arewetland dependent

Great BlueHeron

CanadaDarner

Pickerel Frog

Illustrations courtesyof Fish and Wildlife,

Photo by Blair Nikula

Dammed culverts and flooded roads can createdangerous situations, and when wells and septicsystems are flooded, contaminated water is amajor concern. Home and property damages arecostly impacts of beaver activity. Cleaning culvertsis a time consuming and costly expenditure forhighway departments and property owners.

Tree damageBeavers chew through trees with incredible efficien-cy and can cause significant damage to ornamen-tals or shade trees located near an active colony.Fallen trees also have the potential to interfere with powerlines, roads, or cause damage to private property.Preferred tree species include aspen, birch, cottonwood,poplar, willow, alder, white oak, ash, and apple.

Water quality concernsWater within a beaver pond may be high in organic mate-rial and there can be cause for concern if the exitingwater is near a public water supply. The beaver may be acarrier of a parasite (Giardia lamblia) which causesGiardiasis, an intestinal disease with symptoms such asdiarrhea and intestinal cramps. Giardiasis occurs world-wide and is also carried by humans, livestock, birds anda variety of other wildlife. Proper hygiene and sanitationcan prevent Giardiasis and other water borne diseases.

R U L E S A N D R E G U L A T I O N S C O N C E R N I N G B E A V E RThe beaver is a protected furbearer under Rhode Islandgeneral law (RIGL 20-16-1). The Division of Fish andWildlife established a regulated trapping season forbeaver in 1995, in response to increasing population lev-els, increased complaints from property owners and theknowledge that a limited harvest would not adverselyeffect the state’s beaver population. Trappers must fol-low regulations set and enforced by the state. All trap-pers participating in beaver trapping must obtain a spe-cial permit issued by the Division of Fish and Wildlife inaddition to their current RI trapping license. All beaverpelts must be presented to Fish and Wildlife for tagging.The Division of Fish and Wildlife may authorize the trap-ping of beaver outside of the open season when publichealth or safety is a concern. Additional information canbe obtained from the Division of Fish and Wildlife FieldHeadquarters at the Great Swamp Management Area.

- 2000

M A N A G E M E N TThe Division looks to manage beaver with the followinggoals in mind: minimization of property damage bybeaver, maintenance of healthy beaver populations andhabitat throughout the state, and to educate the publicabout ways to coexist and be tolerant of beaver activity.The first step in managing for beavers is to understandthat beaver activity becomes a problem only when it con-flicts with human activities. Beavers will readily occupyhabitat close to human activity. Humans have oftenmanipulated the environment in such a way as to make itattractive to beavers, often unintentionally replicatingbeaver wetlands. Man-made ponds and impoundment’s,and roadways bisecting wetlands with undersized cul-verts will readily be occupied by beavers. It is importantfor humans to be proactive when it comes to coexistingwith beavers. Tolerance of beavers and other wildlife iscrucial if we are to coexist with wildlife. Understandingthe biology and behavior of the beaver, its ability to alterlandscapes and the options available for managementwill minimize human-beaver conflicts. An increased toler-ance and understanding about beavers, and the use offencing and pipes will often resolvesite specific problems however thesemethods do not in any way controlthe growth of beaver populations. Aregulated harvest helps to stabilizepopulations and reduce conflict situa-tions. With no natural predators ordiseases, beaver populations cangrow to levels that exceed the capaci-ty of the environment to supportthem.

7

“ An aspen tree, felled by beavers, created a potentially dangerous situationwhen it came to rest on power lines in Exeter

Photo courtesy of Fish and Wildlife

Photo courtesy of Fish and Wildlife

Streamflow diverted because of a beaver dam on a statemanagement area road in Coventry.

All beaver related damage or problems should be reportedto the RI Division of Fish and Wildlife. A number of man-agement options are available: trapping during the openseason, protective fencing, and water control devices. Themost effective long-term management will involve a com-bination of these options. An important consideration isproperty ownership. Often times the location of the damor blocked culvert is not on the property of the affectedlandowner. Before any actions can be taken the approvalof the property owner must be obtained.

Removal of beaver damsThe removal or breaching of beaver dams does notrequire a permit from the RI Division of Fish and Wildlifehowever if it is a defined alteration of a freshwater wet-land you need to contact the RI Division of WaterResources (235 Promenade Street, Providence , RI 02908401-222-6820).

Breaching a beaver dam or removing material blocking aspillway can provide immediate relief from high waterlevels, but is likely to be short-term. An establishedcolony of beavers will repair the dam nightly. If you arereading this publication you are probably already awareand maybe even admire the beaver’s perseverance.Breaching the dam in the morning will usually allow thepond to drain throughout the day. A long handled potatofork with long tines is the most effective tool to use.Always keep in mind your safety and the potential effectsof discharging a large volume of water downstream.

Beaver trappingTrapping is a highly regulated activity. Regulations areestablished by wildlife managers to protect wildlife fromexploitation. A regulated harvest is the most direct wayto control beaver populations and allows a landowner tomanage the number of beaver on their property. Trapping

often proves to be the most economical short-term solu-tion in nuisance situations. This management optionrequires cooperative efforts between landowners, trap-pers, and wildlife managers. Trapping requires specialskills and should only be conducted by experienced,licensed trappers. Trapping season dates are establishedby wildlife biologists to coincide with the time when peltsare of the highest value. In this way beaver are utilized asa renewable natural resource. Only a percentage of thepopulation is removed in any given year. Successfullong-term management of beaver populations goesbeyond the trapping of individual beavers however. It isimportant to understand that the features that attractbeaver to an area will always draw beaver to that site. Itis not the policy of the Division of Fish and Wildlife to livetrap and relocate nuisance beaver. Due to the difficulty,time and expense involved in addition to the lack ofunoccupied habitat into which beaver can be releasedrelocation is seldom justified as a means of resolvingproblems. Moving problem animals from one location toanother only creates another potential problem for otherlandowners. Experience has shown that relocated ani-mals do not always remain where released, as what oftenappears to be "good habitat" to humans may not appearso to the beaver.

Tree ProtectionValuable ornamental trees located near a beaver occu-pied waterway may be damaged or felled by feedingbeavers. In our area white oaks, tupelo and fruit trees areoften targeted. The best way to protect individual trees isto encircle them with a stiff wire mesh with a mesh open-ing no larger than one and a half to two inches. Fencingshould be securely fastened with metal stakes and main-tain a minimum six to eight inch perimeter between thetree and wire. Fencing should be no less than thirty-sixinches high but does not have to be higher than forty-eight inches.

The trapping of beaver and other furbearers for their pelts and other products has a long tradition in North America.

Protecting culverts with fencingStudies have shown that culvert sizeis the major determinant of whetherthe pipe would be blocked bybeavers. Most roadway culverts inRhode Island were installed at a timewhen beaver activity was not a con-sideration or concern. Wheninstalling new culverts or replacingculverts in locations prone to beaverproblems, the installation of box-typeculverts or oversizing culvert open-ings to maintain as much of the natu-ral stream width as possible shouldbe considered. A wide variety of exclosure designsfor culverts have been tested againstbeaver plugging activity. The idea isto prevent a beaver from being ableto completely clog the inside of aculvert or pipe. Culverts filled withmud and sticks are very difficult toclean and may create a dangeroussituation. In their simplest form cul-vert exclosures are constructed toprevent the beaver from entering theinside of the culvert pipe. Often thedownstream side of the culvert mustbe protected as well. Fencing and support posts must beable to support the additional weight of material thatbeaver will pile on the outside of the fence. The installationof any type of structure requires periodic inspection andmaintenance. All devices will eventually fail if not properlyconstructed or maintained. No two locations are the sameand what works in one situation may not work in another.The movement of fish, reptiles, amphibians and otherfurbearers should be considered when designing exclosurestructures. These structures should not restrict the normalmovement of wildlife.

Water level controldevices (WLCD)Water level control devices(WLCD’s) are any structures thatdesigned to allow the passage ofwater through a beaver dam. Theyalso should prevent beaver fromaccessing the water intakes. Thesedevices should also act to reducethe sound and sensation of flow-ing water, which stimulates thebeaver to build dams. There are anumber of considerations wheninstalling a WLCD. Not all sites willbe suitable. WLCD’s must be mon-itored regularly to avoid devicefailure. During installation, thewater must be drawn down to thedesired water level and safety pre-cautions should be kept in mind atall times. The following recom-mendations for where a WLCDshould be used are:• Where some rise in water levelscan be tolerated.• Where one main dam is locatedat the outfall of a waterway.• Where a beaver has little oppor-tunity to counteract the device

(avoid areas that provide numerous dam sites), and wheredownstream flow is not constricted.• Where there will be three or more feet of water at theintake end of the pipe.• In ponds with clay or gravel bottoms (these substrates donot provide material to beavers to block the intake).• In accessible sites, because inspection and maintenanceare important to the success of a WLCD.Common WLCD materials include Polyvinlchloride (PVC)pipe, corrugated flexible polyethylene tubing, corrugated gal-vanized steel pipe, and welded wire cylinders.

» In a beaver dam that does notdirectly involve a man-madestructure (culvert, water controlbox, dike).

» In a beaver dam wheretemporary flooding is tolerable(flooding to the original level).

» In areas where a beaver haslittle opportunity to counteract thedevice (avoid areas that providenumerous dam sites), and wheredownstream flow is not constricted.

» In ponds of 4 feet or more, orif not, where the device muffles theflow of water to the intake and/orthe device protects the intake withan exclosure.

» In ponds with clay or gravelbottoms (these substrates do notprovide material to beavers to blockthe intake).

» In accessible sites, becauseinspection and maintenance areimportant to the success of a WLCD. 9

RECOMMENDATIONS FOR WHEREA WLCD SHOULD BE USED

Fencing placed around a culvert on a state management area. The pipes will allow for additional flow during high water conditions

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CLEMSON POND LEVELER - This device is designedto reduce the sound and sensation of flowing water. It isbest used in ponds that have a relatively small input,because the Clemson Pond Leveler is not designed tohandle large amounts of water. Occasional flooding maybe expected. The leveler has specific installationguidelines and assemblage instructions, outlined below:

1. The intake should always be under water, toeliminate the sound of trickling water. A minimum of 2feet of water at the location of the leveler isrecommended.

2. The intake requires 150 2-inch holes drilled into 10inch PVC (13 foot section) with a 3 foot diameter (10 feetin length) wire mesh cylinder surrounding it. Theperforated intake device is designed to spread water flow,which eliminates much of the sound of running water.

3. At the end of the intake device, use a reducer toattach two lengths of 8 inch PVC.

4. Place the outlet as far from the dam or culvert aspossible to make it less likely to attract beaver.

Water level control devices (WLCD)Shown below are some basic types of WLCD’s which can be used in a beaver dam or at a culvert pipe.

COMBINATION DEEP WATER FENCE/ PIPING -Piping and additional fencing is used in conjunction withfencing at a culvert opening or beaver dam. An enclosuremade of wire fencing is placed in deeper water a shortdistance from the culvert. A length or several lengths ofpipe set at the desired water level is extended from thefence through a dam or to a fenced area around a culvert.An elbow connected to the intake end of the pipe andpointed downward will help to reduce the sound of flowingwater. The fencing prevents activity at the pipe intake and atthe culvert intake. If beavers place material against thefencing it must be cleared away periodically to allow foradequate flow.

TRIANGULAR WIRE MESH AT A CULVERT OPENING -Using six inch by six inch concrete wire mesh anexclosure is constructed at the intake end of culvert orspillway. The larger mesh size of the concrete wire allowsleaves and most other floating debris to pass through.Additionally, most fish, turtles and small furbearers canpass through as well. The size of the exclosure shoulddepend on your ability to access and clean material fromthe outside of the fence periodically. Larger exclosure sizesor irregular shapes provide more surface area and mayreduce the sensation of flowing water but may be moredifficult to maintain. Fencing must be placed along theroadbed or headwall side of the structure to preventbeaver from entering it. The fencing must be reinforcedwith posts to support any additional weight placed againstthe fence by beavers. When water levels rise abruptly thedam will act as an emergency spillway.

POND DRAIN PIPES - A pond drain pipe is installed topass directly through a dam. The pipes are best suited forponds that have a hard bottom to delay the buildup ofmaterial around the intake. Often more than one pipe isrequired to maintain adequate flow. The intake (upstream)end of the pipe should extend out to a location where thereis a minimum of three feet of water depth. To reduce thesound level of flowing water an elbow can be attached tothe intake end of the pipe. With the opening pointeddownward, water will still enter the pipe. Two-inch diameterholes drilled along the bottom of the pipe will also aid theflow of water. Steel posts should be used to support thepipe or pipes in the water, with cross bracing to hold thepipes rigidly in place. Drain pipes require regular inspectionand routine maintenance but can be relatively inexpensiveand easy to install.

Graphics and maps courtesy of Fish and Wildlife

S E L E C T E DR E F E R E N C E SChapman, J. A., Feldhamer, G. A. 1982. Wild Mammalsof North America, Biology, Management, andEconomics. The Johns Hopkins University Press,Baltimore and London. 1147pp.

Cronan, J. M., Brooks, A. 1968 revised. The Mammalsof Rhode Island. Wildlife Pamphlet No. 6. Rhode IslandDepartment of Natural Resources, Division ofConservation. 133pp.

D’Eon, R.G., Lapointe, R., et al. 1995. The BeaverHandbook: A Guide to Understanding and Coping withBeaver Activity. OMNR, Northeast Science andTechnology. Field FG-006. 76pp.

Hamelin, D., Dougherty, D., et al. 1996. Beaver DamageControl Techniques Manual. New York Department ofEnvironmental Conservation. 39pp.

Jackson, S., Decker, T. Beavers in Massachusetts,Natural History, Benefits and Ways to Resolve Conflictsbetween People and Beavers. University ofMassachusetts Cooperative Extension System,Massachusetts Division of Fish and Wildlife.

Jensen, P. G., Curtis, P. D. 1999. Managing NuisanceBeavers along Roadsides, A Guide for HighwayDepartments. Cornell Cooperative Extension Program.14pp.

Langlois, S. A., Decker, T. A. 1997. The Use of WaterFlow Devices and Flooding Problems Caused byBeaver in Massachusetts. MA Division of Fisheries andWildlife. 13pp.

Organ, John F., Gotie, R.F., Decker, T. A., Batcheller, G.R. 1996. A Case Study in the sustained use of Wildlife:the Management of Beaver in the NortheasternUnited States. Proceedings of the 68th WorldConservation Congress of the IUCN. 17pp.

Rue III, L. L. 1964. The World of the Beaver. J. B.Lippincott Company, Philadelphia and New York.

Wilson, J. M. 2001. Beavers in Connecticut: Theirnatural history and management. ConnecticutDepartment of Environmental Protection, WildlifeDivision. Hartford, CT. 18pp.

Beaver Distribution in Rhode Island - 1982

Beaver Distribution in Rhode Island - 2000

11

It is the policy of the Rhode Island Department of Environmental Management to offer its services andaccommodations to all orderly persons, and, as required, to all properly licensed persons, without regard to race,

religion, color, national origin, ancestry, sex, age, or disability. If you believe you have been discriminated against inany program, activity, facility, or if you desire further information, please write to the Office for Equal Opportunity, US

Department of the Interior, Office of the Secretary, Washington, DC 20240.

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