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The negative effects of beaver dams in residential areas

 


Flooding is a common result caused by a beaver dam. Although it has a lot of beneficial effects in a natural environment, it can also cause some trouble, for example in a residential area.The water can overflow streets, basements, backyards and croplands.

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Beavers will always want to keep expanding their dam. That’s why they look for an environment which can provide a lot of building material, such as trees. To be able to use these trees, they cut them down and put them on their dam.


Over time, people have come up with “solutions” to stop the beavers from building their dams and even getting rid of them. For most people, the beaver is an animal destroying their nicely landscaped gardens and ponds.

Trapping or killing the beaver, cutting of their building supplies, destroying or sabotaging their dams, these are the so-called solutions people have come up with over the years. People often compare the beaver with a plague and treat them as such.

Water floods a Mill Creek, WA neighborhood after fallen trees pierced a beaver dam at a nearby wetland.

KOMO News

Getting rid of the beaver

Sabotaging the beaver dam

​destruction of beaver dam
https://www.youtube.com/watch?v=V_w_iLSVRYo

Beaver advantages

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Improvement of bio-diversity

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Flora:

studies show that Beavers increase the retention of organic matter by up to seven times and the level of aquatic plant life 20 fold.

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Fauna:

Beavers introduce side canals. Varying animal species will manifest in different sized canals. Besides this they ensure cleaner water and the provision of food by introducing new plant- and other animal species.

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Minimize polutants

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Concentrations of phosphorus halved and nitrate levels lowered by more than 40 percent, although colour and suspended solids concentrations increased.

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Balance waterlevel

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Increasing low waterlevels: Beavers have a required hight of 60 – 90 centimeters to be able to swim under their dam. They regulate the waterlevels in a way so it’s never too low.

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Reduce downstream flooding by enhancing storage and slowing release of water, can both attenuate flooding and alleviate water shortages.

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Improving recreational qualities

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Attracting the animals remain a popular feature of city tours of the area.

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The fishing trend

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It’s important for fish to survive that they’re able to travel an entire river. The beaver dams are thus constructed, so small fish can go through. The beavers create individual fish passes in the form of bypass streams for bigger fish. This way there’s a lot of fish in the Isar, which attracted a lot of recreational fishermen.

Sources:

1. LAW, A.; GAYWOOD, M., J.; JONES, K., C.; RAMSAY, P.; WILLBY, N., J., Using ecosystem engineers as tools in habitat   restoration and rewilding: beaver and wetlands

2. Beaver Benefits – A Keystone Species, via: http://www.beaversolutions.com/beaver-facts-and-benefits-of-keystone-species/, last consulted on 15/12/2017

3. Dams, via: http://fohn.net/beaver-pictures-facts/beaver-dams.html, last consulted on 15/12/2017

4. BURCHSTED, D.; DANIELS, M.; WOHL, E., 2014. Introduction to the special issue on discontinuity of fluvial systems. Geomorphology, via http://dx.doi.org/10.1016/j.geomorph.2013.04.004, last consulted on 13/12/2017

5. Beavers bring environmental benefits to Scotland, 2016, via https://www.stir.ac.uk/news/2016/02/beaver-environmental-benefits/, last consulted on 12/12/2017

biodiversity
Die Renaturierung von Flüssen – Das Beispiel Isar

a: 1 year after beaver release, b: 12 years after beaver release
Using ecosystem engineers as tools in habitat restoration and rewilding: beaver and wetlands                               

A tree felled by beavers next to the Isar in Munich

Photograph Robin Aschoff

Examples of beaver advantages

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Guiding beavers

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In Gatineau Park, near Ottawa. Michael Éclair, instead of killing the beavers to avoid floods, developed a system to interact with beaver so they would build their dams where he wanted them to. It has been working for 30 years.        

1. He played a ‘song of the streaming water where he wanted the beavers to build.

2. The beavers work overnight and bury whatever is making the sound.

3. He introduces a section of pipe in the dams so the beavers would use these.

4. He added a bigger pipe to open and lower the water if it ever was too high.

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Beavers for increasing and retaining water

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In a park close to Alberta, the beaver community was reintroduced years after being exstinguished. Glynnis Hood compared old historical maps realizing that beavers, instead of settling where there’s already a lot of water as it was believed, increase the amount of it: the ponds with active beaver in them had nine times more open water in them than the same ponds without active beaver.

In the summer, when the water level decreases, most of the water in natural areas is where they have beavers.

Historically, farmers were seeking out neighbors who had beaver and consequently water.

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Beavers restored wildlife

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Susie Creek was almost a desert. Beavers transform deserts into gardens. The Park was an area in desertification. Young beavers that swam through the creek unexpectedly and settled there actually saved it. They retain the water if the snow in the mountains melts down too fast. Now you can see baby wildlife being produced around the dam, and species coming to it.

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Reintroducing beavers to heal landscape

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Marnie Johnson, in Beaver’s Valley in Colorado, dreamed of seeing the landscape the way it used to be 81 years ago when she was a kid. She contacted Sherry, a beaver rehabber who provided the valley with a beaver family that was being rejected somewhere else due to new construction. Beavers lock the aquatic ecosystem and can bring it again.

Sources:

Leave it to Beavers, via: https://www.youtube.com/watch?v=yJjaQExOPPY&t=55s, last consulted on 11/12/2017

HOOD, G., The Beaver Manifesto, (Calgary: Rocky Mountains Books, 2011)

GRAY, B., Beavers help Battle ongoing Drought, via: http://climatechange.medill.northwestern.edu/2015/06/25/battle-born-beaver-tale/, last consulted on 15/12/2017

Reintroducing beavers, via: https://www.pbslearningmedia.org/resource/nat14.sci.lifsci.beavers/reintroducing-beavers/#.WjRQFt_ibIU, last consulted on 10/12/2017

How Beavers Build Dams | Leave it to Beavers
https://www.youtube.com/watch?v=yJjaQExOPPY&t=55s

Sources:

http://kvi.com/news/local/beaver-dam-breach-floods-mill-creek-basements
http://wildliferemovalusa.com/beaver-how-to.html
http://www.wildlife-removal.com/beaver-get-rid.html
http://www.humanesociety.org/animals/beavers/tips/solving_problems_beaver.html?referrer=https://www.google.be/

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