Stan’s Beaver Baffler – How and Why

The Stan’s Beaver Baffler device is recommended to be installed instead of flow pipe devices and many trapezoid fence devices because:

1. SBB provides fish/wildlife passage through culverts and dam notches, whereas all flow pipe devices and many trapezoid fence devices partially constrict or totally block fish/wildlife passage.
2. SBB is a low-tech device installed in shallow water, whereas flow pipe devices utilize long 20–40-foot pipes with remote water intakes installed in deep water.
3. SBB is low maintenance, whereas culvert flow pipe devices with small fences need to be maintained four times annually to remove collected debris.

Five Key Features of the SBB work together to create a cost-effective device that accommodates fish/wildlife passage. The low-tech device can be easily installed by landowners, road crews, and natural resource specialists.

1. An elongated lane fence (12-24 foot long and 3-4 foot wide) is oriented upstream.
2. The device is installed in shallow water (1-2 feet).
3. An integral skirt (8-14”) is incorporated as part of the lane fence device.
4. Fish/wildlife passage is provided for both culvert and pond leveler versions.
   • Culvert version – Incorporates short 3–4-foot wings on both sides of the culvert.
   • Pond leveler version – Extends the lane fence past the dam notch a short distance (6-12”) and leaves the lower downstream end of the device open.
5. Materials needed are readily available, livestock panels, steel T-posts, and T-post fence clips or rebar wire.

SBB culvert protection device provides wildlife passage through the culvert and around the wings in a manner that discourages beavers from building a dam in front of the culvert.

The SBB pond leveler device provides fish passage through the dam notch and reduces flooding by protecting the dam notch.

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The How and Why each of the Five Key Features is incorporated into the Stan’s Beaver Baffler device.

1 Elongated Lane Fence

How-A simple lane fence is oriented upstream. The structure is 3-4 feet between the fences with a length of 12-24 feet. The elongated lane fence is also pointed at the upper end.

Why –

Orientation

The upstream orientation of a lane fence discourages beavers from building a dam because instinctively they build their dam across a stream and not up a stream. They seldom attempt to build more than 4-6 feet upstream along a lane fence and never build all the way around it when the fence is 16-24 feet long.

Length of the structure will vary based on site conditions.

A smaller 12-foot fence may be adequate if the dam and pond is newly built, less than 1-year. In this case it may be a lone dispersing beaver that has started a small, but potentially problematic, dam in front of a partially plugged culvert. If the stream is shallow or ephemeral after the culvert has been unplugged and no pond remains, a 12-foot lane fence is adequate. The small 12-foot fence will also serve as a trash rack and deterrent that prevents future debris from blocking the culvert entrance. Dispersing juvenile beavers are not likely to establish a new dam at the culvert site if there is no debris caused starter dam in front of the culvert to encourage the beaver to build a dam.

A larger 16-24-foot fence will be needed to protect a dam notch or culvert when a beaver dam has existed for several years and a breeding colony is well established.

Shape of structure

The elongated lane fence with a pointed upper end was determined to be preferrable to a trapezoidal design. Both shapes will discourage beaver from damming around the device. The differences are:

• The long upstream lane fence of a Stan’s Beaver Baffler will result in the accumulation of floating debris near the lower end of the fence, while water continues to flow into and through the upstream portion of the lane fence. The long upstream lane fence reduces the frequency needed for debris removal when compared to the smaller culvert fences typically built for flow pipe installations.
• The trapezoidal shape is conveniently created when 3 standard 8–10-foot panels are used to protect a 12”-36” culvert. However, the trapezoid shape is prone to accumulation of debris on the upper cross-stream panel that is perpendicular to the stream flow, making it more likely to accumulate debris.
• Structurally the upstream orientation of the lane fence is also stronger than a cross stream trapezoidal fence because water stress is along or oblique with the lane fence whereas pressure is directly onto the upper cross stream fence section of a trapezoidal fence.
• Beavers may try to rebuild a dam where a Stan’s Beaver Baffler has been installed by poking sticks through the openings in the fence panels. The 3–4-foot width will provide adequate room for water to flow through the structure and into the culvert or dam-notch spillway. Some extra maintenance may be needed soon after installation but will decrease once the resident beavers give up trying to dam the new structure.

2 Install Structure in Shallow Water.

How- When there is a choice, install the lane fence in water that is 1’-2’ deep. The lane fence does not need to be built in a straight line, it can be curved or angled to follow a stream channel, or near the shore of a beaver pond to take advantage of shallow water.

Flow pipe devices with water intakes in the deepest part of a pond can be moderately to very difficult installations.

3. An Integral Skirt

How-Create an integral 8”-14” skirt on the outside of the lane fence. Occasionally a beaver may dig under a newly installed fence structure even if a skirt is present. When this happens the problem beaver can be blocked by adding an additional larger section (2×3 feet) of skirting where the problem occurs. Skirts are not needed where culvert wings are above water level or lane fences pass thorough a beaver dam notch.

The integral skirt was determined to be preferable to installing a separate spiked skirt or routinely installing a solid wire mesh floor to prevent the occasional digging under the fence. All three techniques are successful at preventing beavers from digging under the fence. The differences are:

• The integral skirt can be easily created as part of the fence when being installed.
• The integral skirt utilizes about 1/3-1/2 less fence panel materials than a full mesh bottom.
• The integral skirt covers a smaller area of the stream or pond bottom resulting in a reduced environmental impact related to placement of undesirable material into a stream channel.

4. Fish/Wildlife Passage is provided for both culvert and pond leveler versions of the SBB device. Culverts and beaver dams are very different structures that require different approaches to resolve beaver conflicts. The basic SBB device is the same for both versions, with adjustments depending on if a culvert intake or a dam notch is being protected.

Culvert protection fence version of SBB

How- Wildlife passage is provided by short 3–4-foot wings that are 2-feet high, on both sides of the culvert. The upper end of the wings should be installed about 6”-12” up the bank above normal water level. The lane fence should be about 18” away from the culvert opening. A skirt is not needed where the wing is above water level on the bank.

Why–

Beavers instinctively drag food and dam building material into their pond. They also instinctively add material to the top edge of their dam at water level, sometimes poking and pushing branches over the edge of their dam.

Beavers instinctively avoid dragging dam building material out of a pond, up a bank, around a wing barrier and back down again. Dragging material out of the pond and up a bank is instinctively a bad idea as that is where the predators are and also will not increase the height of their dam. There is one specific exception, beavers do drag material out of the water to increase the height of their lodges, both in the pond and bank lodges.

Small fish are able to migrate downstream through the culvert because water flows unobstructed by a flow pipe through the SBB lane fence into the culvert.

Adult fish migrating upstream to spawn are able to exit the culvert and pass through the upper end of the SBB without being blocked by a culvert screen or flow pipe device.

Pond leveler version of SBB

How- SBB provides fish passage by including a 3-4-foot-wide dam notch that is protected with a lane fence. The fence is extended past the dam notch a short distance (4-10”). The lower end is left open where the dam notch transitions into a spillway.

Why-

The open lane fence at the top of the spillway accommodates fish and aquatic wildlife movement across the dam.
Beavers live and build their dams where water is slow moving. They build and maintain their dam by floating material to the dam, then adding it to the top or pushing it over the dam from the top.

Beaver instinct is to avoid building dams in fast water with a steep gradient or on the lower portions of an established dam. They will avoid blocking the lower end of the lane fence through a dam notch because it is hard for them to successfully build in fast moving water and steep slopes of a dam notch spillway.

Fish passage is adequate when a dam notch is protected by a Stan’s Beaver Baffler, whereas a flow pipe device will constrict or block fish movement.

5. Materials and Tools Needed.

Materials needed for construction.

How – Simple is better, that is a key philosophy of the Stan’s Beaver Baffler.

1. Livestock panels or concrete reinforcement mesh. 2-4 panels – galvanized 4-6 gauge 16’Lx48”H, mesh grid 6”x8”, 6”x6” or 4”x4”.
2. Steel T-posts, 7-15 posts – 5.5’ foot 1.25lbs/foot type
3. Fence clips, 30-60 fence clips/ties or rebar wire ties.

Materials cost for a typical 12’-24’ SBB structure is $150-$300.

Why-

The device is designed to function with a minimum of materials to assemble and install. The three items needed to create and install a Stan’s Beaver Baffler are readily available at numerous farm supply stores.

1 – Fence materials are galvanized welded wire livestock panels or ungalvanized concrete reinforcement mesh. The type of mesh used for the fence will depend on availability and site-specific needs for fish and wildlife passage.

6×6 inch mesh welded 6-gauge ungalvanized concrete reinforcement.

This mesh size is effective at stopping beavers and allows small and moderate size fish to pass through. Small juvenile beavers may occasionally pass through a 6”x6” mesh fence. Available as concrete reinforcement mesh and is ungalvanized. Commonly available as large panels 4’x16’ and can be cut to 4’x8’ for transporting and installing. Sometimes available are smaller panels and with epoxy coatings. Available at metals supply and other industrial metal outlets.

6×8 inch mesh welded 6-gauge galvanized wire livestock panels.

The larger 6×8 inch mesh size is recommended for sites with large fish such as Coho salmon or locations with large turtles. Juvenile beaver may occasionally pass through the panels, however the young beaver may not be effective at rebuilding a plugged culvert or dam notch. These panels have vertical 4 gauge wires and horizontal 6 gauge wires. Commonly available as 4’x16’ livestock panels and can be cut to 4’x8’ for transporting and installation. Available at Tractor Supply and other farm supply outlets.

4×4 inch mesh welded 4-gauge galvanized wire livestock panels.

This mesh size is effective at stopping beaver and allows small and moderate size fish to pass through. Small juvenile beaver will also be excluded. These panels are strong and very resistant to fence collapsing or rusting. The 4×4 inch mesh grid livestock panels can be used to create an 8-foot panel section that discourages beaver next to a culvert or dam notch while using larger 6×8-inch mesh grid panels for the upstream portion of a structure to provide large fish and turtle passage. Commonly available as 4’x16’ livestock panels and can be cut to 4’x8’ for transporting and installation. Available at Tractor Supply and other farm supply outlets.

2 – Steel 5.5’ T-posts are utilized to support the Stan’s Bever Baffler lane fence. Beaver Deceivers™ utilize wooden posts for installation while Keystone fences™ and Flexible Pond Levelers™ utilize steel T-posts. The steel T-post does not deteriorate over time and is safer to install as it does not require a ladder and sledgehammer needed to install wooden posts. Available at Tractor Supply and other farm supply outlets.

3 – Fence clips or rebar wire-ties are utilized to attach wire panels to the T-posts when installing a Stan’s Beaver Baffler. Available at Tractor Supply and other farm supply outlets.

Tools Needed for Installation.

How- Tools include only 4 items to install a SBB device.

1. T-Post Driver
2. Medium 24” bolt cutters
3. Fencing pliers
4. Custom wire bender

Why- Easy to install is a key feature that is incorporated into the Stan’s Beaver Baffler design.

1. T-Post Driver —Cost $40-$100. Much safer and easier than using a sledgehammer.
2. Medium 24” bolt cutters — Inexpensive 18” bolt cutters will work, however, medium grade made in USA 24” bolt cutters make the job a lot easier. Cost $25-$65.
3. Fencing pliers — $15-$28. Best to get the better quality made in USA.
4. Custom wire bender — The wire bender is used to bend wire prongs when connecting panels together. You need to make it yourself using a 6” long ½” galvanized pipe nipple with a pvc cap on one end. Drill a hole in the cap and attach a lanyard so if you drop it in the beaver pond you can find it again. Cost $4.

Note: No pipes, screens, hammers, nails, bolts, staples, screws, boards, connectors, concrete blocks, floats, step ladders, sledgehammers, or power tools are required to install a Stan’s Beaver Baffler.