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Friday, September 30, 2016

The Otter river Beavers of England

In a previous blog, I wrote about the Tay-catchment beavers in Scotland.  Now the English have got in on the act.  A couple of beavers 'appeared' in the Otter River, on the South Coast of England in Devon and now the Powers-that-be have allowed the introduction of a second pair further up in the catchment so that when the two populations meet, there will be greater genetic diversity in the united populations.  First a little information on where you can see these beavers.

You head for Devon on the South Coast out toward the West and set your navigator to Otterton.  It is a village near the mouth of the Otter River.  There are a number of places you can stay and I can heartily recommend the Kings Arms.  Book ahead because tourism is picking up with people coming to see the beavers.

To see the beavers, I would highly recommend getting there before first light in the morning.  You will also see beavers in the evening and even occasionally in the middle of the day but morning seems to be the best time.  Starting from the Kings Arms, you walk west along the main road (back the way you entered Otterton) past a working flour mill on the left and across the bridge that crosses the Otter River.  Just past the bridge, you will find a gate on your right and beyond the gate a well trodden path.

Head upstream (downstream is also a nice walk and you can walk along side a wetland and down to the sea).  As you head upstream, you will pass a weir that directs water to the flour mill in Otterton.  It has a fish ladder built into it.
 Image result for otter river fish ladder image

A short way further on you will pass a wooden bridge over the Otter.  It arks up to the East side which is considerably higher than the west side where you are walking.  From here on, keep an eye on the small trees to the left of the path.  You will see beaver cut branches here and there.

Keep going (20 minutes to half an hour from the gate at the start of the path) until you come to a well trodden place on the side of the river.  If you sit on the edge of the river and look upstream you will see a bed of bull rushes and on the East side of the river, a small beach.  The beavers often haul out there.  If you look a little way down stream, you will see a pile of branches up against the far bank.  This is where their burrow* is located.

* When first introduced to a new area, beavers often make burrows in the river bank for raising their young.  Later, when they dam feeder streams, they construct a lodge in the pond they have created for their nest.


At present (Sept 2016), the adult pair have five kits.  Generally when beavers are introduced to a new area, their population expands at about 25% per year.  This only requires one surviving kit every two years.  Clearly the potential for an increase in population is much greater.  The kits stay with the parents for an additional year and help them to look after the next batch of kits.When the adults are building dams, lodges and food stores, they help with this too.  They become sexually mature around the end of the second year and the parents drive them out.

A second place you can see beavers is from the middle of the wooden bridge.  You may need a pair of field glasses.  Look upstream to where there is a wee beach.  They often haul out there.

Before I start, have a look at these beavers.  This footage was shot by Sylvia Meller, wild life photographer extrordinaire.  I had gone to England with no thought that I would be able to go and see the beavers of Devon and didn't have a camera with me.  Spot the dummy.  However these pictures are far better than anything I could have shot.  Look up other works by Sylvia.  They are great.

The territoriality of beavers, the fact that they drive out their young after they have reached maturity,  has an interesting consequence.  Once the available location in rivers and streams are occupied, the population overshoots slightly each year and then falls back to its carrying capacity.  Unlike many other animals, you can't have a population explosion of beavers.

The only way you can increase the beaver population is by making new areas attractive to beavers (by, for instance, truncheoning in a new forest of deciduous trees on the banks of a stream).  Tiny seeps that hardly deserve the name of a stream can be occupied by beavers if the habitat is provided for them, creating a pond on your farm.

I just read a web site (which shall remain nameless) that stated that the European beaver Castor fiber unlike the America beaver Castor canadensis does not build dams.  I hate to rain on your parade guys but  European beavers definitely make dams and be thankful that they do.  Almost all the massive benefits that beavers bring to a catchment depend on the fact that they do make dams. In a new area, beavers tend to build their burrows* on the banks of the main river but once these locations are taken up, they will move into the secondary streams where they build dams to make ponds for their safety.  Let's catalog the benefits from beavers.

Water flow regulation
Beavers store water on the land in a number of ways.  This is particularly important in the catchment of the Otter.  The underlying strata is mainly sandstone and water doesn't infiltrate the aquifer quickly, unlike outwash plains such as the ones found East of the Rockie Mountains in the USA or to the East of the Alps in the south island of New Zealand.  In the Otterton, most of the water from high rainfall events shoots down to the sea in a day or two.  Of course, if these are unusually high rainfall events, they cause flooding.  So how do beavers store water.

First, of course, are the ponds they create with their dams.  Depending on the topography of the particular area where they build their dams, they can store considerable water.  Beaver dams are somewhat leaky so some water is leaked downstream and water also seeps downward into the underlying strata. holding the water on the land allows time for the water to infiltrate the 'reluctant' aquifer.  

Secondly, the ponds raise the water table in the surrounding land.  Water tables intersect streams at the surface of the water in the stream.  As the water rises in a beaver dam, the surrounding water table rises as well.  In particularly propitious cases, a field which had to be irrigated, now doesn't need it since the field crops can access the underlying water table.  Water then leaks from the raised water table down steam from the beaver dam.
 Image result for diagram of aquifer stream

Thirdly, the dams simply roughen the macro contours along a stream.  Even if all the dams are full when a rainfall event occurs, just having all these dams in place slows down the water flow to the sea.  All these effects lower peak flows and raise low flows.

Check out this rather neat cartoon.

And fourthly on a long term basis, beaver ponds catch bed load, suspended sediment, wood chips, scats of various animals, spawned-out salmon and so forth creating a deeper and deeper sponge.  Over time, this water retaining sponge increases and the effect of the beavers dam causing steam flows become more and more even.

Beavers sometimes abandon a site in which case, over time, the dam breaches and the beaver pond becomes a wetland with all the benefits this brings.  Wet lands are rich ecological environments, slow down stream flows, catch sediment, hold water and in short still fulfill many of the beneficial functions of beaver ponds.  Generally, after a while, as the deciduous trees move in from the boarders of the wet land, a new colony of beavers will establish themselves in the same area and create a new pond above the wetland.

A beaver dam, obviously, gives rise to a location with dependable deep (a few meters) water.  Where before you had a stream, riparian zone and surrounding fields or towns, now you have a new environment.  In addition, you have more dependable stream flows than in streams where there are no beaver dams, with none of the exceedingly low flows which are inimical to much wild life or floods which are inimical to people's structures.

In the pond, animals such as water voles and muskrat can prosper.  Water birds find shelter in the middle of the pond from predators and will nest in the reed beds that develop along the margins of a beaver pond.  A whole range of invertebrates, which only prosper in still water can grow and form part of the food chain for larger animals.  Dragon flies, which are excellent predators of flying insects such as mosquitoes and flies can lay their eggs.

A detritus cycle develops in the pond based on the bits of cellulose (water log wood chips, leaves, twigs etc) that the pond catches.  This cellulose based detritus feeds a wide variety of fauna. 

A beaver pond becomes the 'go to' area to sit and watch wild life.

Benefits to Salmonids
Here is where the beaver pond really comes into its own.  Many of the salmonids lay their eggs in redds.  These are gravelly areas in a stream.  Things that decrease the success of hatching include floods which wash out the eggs from the redds, excessively low water which doesn't provide enough oxygen to the eggs and silting up which smothers the eggs.  Beaver ponds ensure an even  flow of clear water.  This is especially important today with increased silt from farming.  Beaver ponds catch this silt and protect the redds.

Once the eggs have hatched, the tiny salmon are prone to predation from the water and from the air.  The beaver pond provides water which too deep for wading birds and create many many niches in the front wall of the dam, in amongst the branches of the lodge and in the  food store of branches.

In areas where the streams freeze in winter, the beaver pond provides water deep enough not to freeze.  In addition, spend adult salmon are caught by the beaver dam and add to the nutrient content of the pond and the surrounding land.   Essentially, the bodies of the adults provide the nutrients for their young.  This is one of a few cases of nutrients flowing upstream from the sea to the land. Various animals which feed in and around the pond spread their dung upslope, enriching the surrounding area.  Without beaver ponds, the spent salmon wash down to the sea.

I have anglers and even fisheries biologists, who should know better, argue that a beaver dam stops the upstream migration of adult salmon. It is not for nothing that the Atlantic salmon was name Salmo salar .  In Latin it means 'the leaper'.  For a sex crazed Atlantic Salmon that can jump great waterfalls in a single bound and which is heading upstream for its once in a life time act of procreation, a beaver dam is just a little morning warm up.  I think where the confusion arises, is that Salmon will rest in the plunge pool below a beaver dam for a while before continuing upstream.  Sometimes they wait for a wee freshet from a rainfall event to point the way.  Not a bad adaptation when you consider that the stream above the beaver pond will be fuller following a rain.

It is interesting that anglers, who quite correctly have been removing tires, old car bodies and other junk from their streams, also remove fallen trees.  You can see one such case along the Otter.  If you look at the opposite bank as you walk up the stream, you will see the butt of a tree that has been chain sawed off.  Have a look at this web site on 'big wood'.

Incidentally, with the decrease of ice in the Arctic Ocean, Pacific salmon have been found for the first time in streams flowing into the Arctic Ocean and even as far as Greenland.  Since we are not going to mitigate the melting of the Arctic, this migration is bound to continue.  It wouldn't be too surprising to find, some decades hence, some strange salmon swimming upstream in British rivers.

For the purist, this will be anathema.  Of interest, though, are the wide variety of life styles of the Pacific Salmon (also mentioned in the above link).  They range from the pinks and chum which tend to spawn in streams near the mouth of rivers and to swim (at night) down to the ocean as soon as they are hatched.  Sockeye, in contrast will swim down a small stream until they come to a river and then turn upstream and find a lake to reside in for a variable number of years.  Some Sockeye will even begin to treat the lake as an ocean and form a landlocked population.  In which case, on the Pacific coast they are called Kokanee.  I understand that Salmo salar also can form landlocked populations.

Benefits to the Riparian Zone
It is vital for the health of a stream that there is a riparian zone.  Such stream verges shade the water, keeping it cool and of even temperature.  The roots of the growing trees and bushes intercept excess nutrients in the ground water flowing toward the stream from farms.  The trees, bushes and grasses bind the bank together so it doesn't slump and pollute the stream and riparian zones provide not only habitat for wild life but also corridors along which they can migrate.

At first glance, you might suspect that the cutting down of a tree by a beaver is  negative.  The opposite is true.  Virtually all deciduous northern hemisphere trees coppice*.  Not surprising since they evolved with beavers.   A beaver cut tree sends out a plethora of branches.  This has a number of effects.  The tree is now protected from becoming uprooted by a storm and exposing raw earth to the stream.  Light can now reach the under-story so that shrubs and grasses prosper.  Their root masses further stabilize the bank.  The young vegetation is lower where it can be accessed by, for instance, deer and the flush of new vegetation is food and shelter for a variety of animals and birds.  Of course, the new branches supply both food and building material for the beavers.

*Sprout from a stump

When a beaver pushes an unpeeled branch into his dam, it will often sprout and the roots grow down into the dam, greatly strengthening it.  Often, though, the beaver will first eat the bark before using the branch as building material.  As the beaver pond matures, many forms of vegetation such as Bull Rushes, Lilly Pads, pond weeds and so forth will take up residence in the pond.  More and more, they form the food of the beavers and bark becomes a smaller part of their diet.  It's a pretty neat adaptation.  In a new location, beavers can use their building material for food until the pond vegetation develops.

Stream Hydrology and Ecology
The river Otter is an ideal location to have the first English introduction of beavers.  It has been well researched in terms of the relation between stream flow and rain fall events, the frequency of flood and low water events, knowledge of the flora and fauna of the stream, especially the trout and salmon and the flora and fauna around the stream.  If our talks with residents is anything to go on, there is a great interest in the re-introduction of this long missing native of Britain.   The Otter is about 32km long with many small feeder streams.  It is surrounded mainly with farm land and has a couple of villages along its length that are periodically flooded.

No major effects of the beavers will be seen until they decide to move into the feeder streams and build dams.  Because the Otter is so well researched, it will be an ideal case study to document the effect of the return of the beavers.

How to get a beaver pond on your farm.
Now is a great time for the people living in the catchment to prepare the areas they want beavers to settle.  It is very easy to establish a food and building supply for beavers and since they are in small numbers to date, there will be time for a wee forest to develop before the beavers discover the location.  Truncheoning is the answer. No need to plant expensive seedlings.

Find an appropriate deciduous tree.  Beavers most appreciate willows but aspens, poplars,  birch and many others will do.  Avoid evergreens.  Sometimes beavers will utilize them but they much prefer deciduous trees.

Fell the chosen tree, cutting it at, say, knee height.  It will sprout and before you know it, you will have the tree back in all its glory.  cut the entire tree into pieces about as long as your fore-arm.  Small twigs can be cut with pruning sheers, large ones with your chain saw.  Large logs, I usually split in four and sharpen the bottom end with an axe.  Wrist diameter pieces, simply sharpen.  Small twigs leave as they are.  You can leave the cut pieces in the shade for a couple of days and some people recommend doing this.  I have usually used the pieces the same day.

Head for your chosen site with an iron bar and an axe or sledge hammer.  You need a  location in which there is some moisture in the ground. After a good rain is not a bad time to do this so in England that means almost any time.

Pound the larger pieces into the ground.  If the ground is hard, the iron bar can be jammed into the same hole a few times, rotating it around after each thump.  For the smaller pieces, simply make a hole about a third of the length of the truncheon with the iron bar, drop in the truncheon and heel in.  Protect from deer and rabbits if this is a problem in your area.  Soon you will have  a forest to make a happy beaver.

Mitigating beaver damage.
Since we have taken over the habitat of the beavers, we will not be pleased if they cause a road to wash away, flood a favorite field or cut down our fruit tree.  Mind you, before you use the following measures, ask yourself if a flooded field might not be of benefit.  There are many benefits to having a pond and/or wetland on your farm.    However, suppose you have decided that you don't want a field or building flooded.  The answer is simple.  You simply install a beaver deceiver.

Get a piece of that corrugated flexible black plastic pipe which is long enough to reach into the pond, over the dam and to the water below the beaver dam.  Dig away enough branches during the day to lower the water level to where you consider appropriate.  Lay in the pipe.  Pound in a stake on either side of the pipe on top of the dam.  Nail on a cross piece touching the top of the pipe.  The beavers will repair the damage you have made that night.  then get a piece of wire weld mesh with a hole size of  abut 10cm and a bar diameter of six or eight millimeters.  The mesh they use for cement reinforcing is ideal.  Form this into a cylinder, cut out the cross bars at one end and pound it into the bottom of the pond at the intake of the pipe.  If you like, you can put a lid on it and pound it in so that it is completely covered by the water.

If your favorite fruit tree is within about a hundred yards of a beaver colony, put a layer of chain link, wire weld or chicken wire around the trunk.  Problem solved.

To finish, lets summarize a few beaver facts

1/  Beavers do not eat fish or any other animal.  The only eat vegetation.

2/  Beavers. once they start building dams, reduce flood peaks and increase low water flows.

3/  Beavers greatly increase ecological diversity

4/  Beavers enhance salmon and trout populations

5/  Salmon and trout pass upstream and downstream over beaver dams.

6/  Beavers are not responsible for Giardia in streams.  New Zealand doesn't have a single beaver and some of her rivers contain Giardia.

7/  Beavers improve riparian zones by felling trees in the zone

8/  Flooding of some feature such as a dwelling or orchard is easily mitigated

9/  Damage to a favorite tree is easily mitigated

10/  Beaver dams reduce the concentration of nitrates and phosphates in a stream

11/  Beaver dams in the catchment of a hydro electric dam increase the amount of electricity the hydro dam can generate, the amount of water that can be used and extend the life of the hydro-electric dam by intercepting bed load and sediment.

Tuesday, March 29, 2016


There is great excitement over President Obama's visit to Cuba and his talks with Raul Castro.  And in Cuba Obama pushed the American line about the need for Cuba to embrace human rights and democracy.

Did you ever wonder why America was so furious at Cuba.  Her excuses over the last few decades were generally that Cuba wasn't a democracy and she was a communist country right on American's door step.

Pretty wild when you consider that America has, with the possible exception of her Marshall plan in Europe (and the motivations there were otherwise)* has never, not ever, not once promoted democracy anywhere in the world.  In fact just the opposite is the case.  John Perkins in his book Confessions of an Economic Hit Man  describes the process.  First America sends in what he calls the Hit Man.  This is an operative, such as John was, who with a combination of the carrot and the stick tries to persuade a new head of the government, whether elected, appointed or elevated to the position in a coup that he should cooperate with American aims.  This generally involves allowing American companies free rein in the country.

The shoring up of Europe after the war, including Germany had a positive motivation, at least by Marshall, of not repeating the mistakes after the first world way and beggaring Germany, leading to the second.  However the main motivations were A, to have a bulwark against Russia and B, to weaken Great Britain vis a vis her empire and to take over her world interests.  Do you realize that the quid pro quo for Lend Lease was access to British markets and military bases around the world.

If the Hit man doesn't succeed, America sends in the so called Jackals.  These are generally CIA operatives who disrupt the country and get the glorious leader deposed or in some cases killed in order to get a more compliant person leading the country.

If that doesn't work, they use false flag operations and the army.

One of the systems the Hit men use is to give the country huge loans for, for instance, the development of a hydro electric scheme.  The pricing is far above the value of the project and the client country doesn't see a cent (except for bribes to the glorious leader and arms for the army that he uses to keep his own people in line).  An America company such as Haliburton (Dick Cheney) does the work and gets the money.  When the country defaults on the loan (from the American bank mis-named The World Bank) America agrees to take payment in various ways such as the resources of the country.

As for Communism, which America complains about*, the only country I know that actually has had real communism is Israel.  Her Kibutzim were actual communism.  Not dictatorships aka Russia or China.  And Israel is America's staunchest friend.

*The new word she uses to justify doing anything she wants anywhere in the world is Terrorism.

No, the truth is that America was pissed off at Cuba and Fidel because it is the only example I can think of where a local took back his country for the benefit of his own people and kicked out American mining companies and agricultural companies who were ripping off Cuba and turning her people into serfs.

Generally, America loves to have a dictator in charge of a country.  If he can be corrupted, he will spread the largess to a few concentric rings of people and the army and keep control of the country for his own pecuniary benefit and serve the American corporatocracy.  America is not keen on having a democracy because each time there is a change of government, she has to start the corruption process over again and who knows what sort of patriot could be elected and prove difficult.

What America dislikes most of all, though,  is a dictator who is against America.  Fidel Castro once joked that if there was an Olympics for foiling the most American assasination attempts, he would be the clear winner.  And it is unlikely that Cuba would have stayed out of the clutches of America if she had had a democracy.  Only a dictator could act fast and effectively enough to stave off the constant attempts of America to get Cuba back under her thumb.  The Bay of Pigs was a good example.  First America flew reconasance over Cuba, then bombed her air fields and then sent in the rag tag army of Cuban exiles in the certain knowledge that the president would send in the regular army when the Cuban exiles failed.

Fortunately they didn't count on President Kennedy who scuppered that neat little plan.  This is one of a number of  possible reasons why he was shot down in Texas.  He thought of the Joint Chiefs of Staff as a bunch of delusional old men and wanted to break up the venal CIA and scatter them to the winds.

What I liked most about the visit by Obama was Raul's comments to Obama.  He told Obama that with respect to human rights, Cuba considers affordable medical care for all her citizens and free education are both human rights and America should up her game before criticizing Cuba.  Sad for Obama since, at least as far as medical care goes, he fought for this.  However he had to 'take it' in his position as president.

Later. Fidels message to the Cuban people was Beware of Americans bearing gifts*.

Now we have the sad spectacle of the primary elections, even in the inappropriately named Democratic party between Sanders and Clinton.  One would expect this from the Republicans but one would hope that a party called Democrat would have more respect for the concept.  Look, for instance at the discrepancy between the voting in each state and the exit poles.  Also have a look at:

Fidel Castro made some pretty negative comments about Obama's visit stating essentially that Cuba doesn't need hand outs from the US. Some commentators in the USA talked as if Fidel was rambling and out of touch with the Cuban people.  If there is a disconnect, it is the Cuban people who are out of touch with their leader.  They would be wise to listen to the old fox.

Have you noticed that America still has sanctions in place against Cuba.  If America was serious about good relations with Cuba they would simply remove these sanctions and let Cuba access the American market with her products.  Instead she is keeping the sanctions in place to be used to bargan with Cuba to get her businesses back into Cuba.  America business would dearly love to get back to the Batista situation in which American business dominated Cuba and Cubans provided cheap labour.  Cuba should listen to her old revolutionary.  He knows what he is talking about.

Wednesday, February 10, 2016

Our homing muscovy duck

I find this hard to believe and completely unexplainable.  We have a female Muscovy duck who was hatched on our property.  She can just about fly well enough to go over a fence and land on our little pond in front of the house.  She laid 14 eggs under an old three wheeler motor cycle and hatched out all three of them.  Unfortunately she and her ducklings took to roosting at night (is roosting the right word for ducks??)  on our front porch.  What a mess in the morning.

Finally, when the babies were only a few weeks old we decided we had had enough.  We found a friendly farmer who raises ducks himself and has a nice big pond.  He lives 6km away across our main highway.  We crated up the ducks and he  came and got them in his pick up truck.  Two days later they were all back on the pond.

We phoned him and asked him if he had changed his mind.  Not at all, he said.  The ducks just disappeared.  Somehow, she had led her small ducklings on a 6km walk.  Somehow she knew where we were in relation to where she was and what direction to go to get home.  Somehow she didn't loose a single duckling.  I'm in awe of her.

Friday, January 1, 2016

The Greenhouse Effect

Much has been written about the green house effect without really explaining what it is and how it works.  I thought I would chip in my two cents worth and hopefully make it make more sense.  I'll start with the Sun which has the mother of all green house effects.  I'll use the sun because it is pure physics with no emotion involved.  Then, when we are in the proper scientific mind set we can look at the earth.

So,,,, the sun started out as a cloud of elements with by far the greatest part being hydrogen.  It collapsed under its own gravity and if you have ever pumped up a bicycle tire, you know that the end where the hose is, warms up.  A diesel engine works on the same principle.  You compress the charge of air about 20 times and it becomes so hot that when you spray in the mist of diesel oil, the oil ignites.  Of course, with a cloud of gas heavy enough to produce the sun, the compression was far greater and the hydrogen at the middle was very hot and very compressed.  It was so hot and so compressed that the hydrogen atoms began to fuse together and produce Helium, releasing large quantities of energy as photons (electromagnetic energy).

This heated up the nearby hydrogen which was hot enough to fuse but not compressed enough.  What is interesting  is that very hot hydrogen absorbs and re-emits the photons produced by the nuclear furnace.  And it re-emits them  in all directions.  Some are sent back toward the core, some sideways and some toward the surface.  All are again and again absorbed, emitted, absorbed, emitted, over and over again.  There are various estimates that for the time it takes for the energy of a photon to reach the surface of the sun but all are in the thousands of years.

Compare this to what the situation would be if each photon created in the centre of the sun was not absorbed by the overlying hydrogen.  As quickly as the energy was produced it would travel through the overlying hydrogen and leave the sun.  Remember that it only takes 8 minutes for the energy of the sun to reach us once it has reached the surface and we are 93 million miles from the sun.  Instead of staying in the sun, the energy would leave the sun in about 1/2 X 8minutes / 93 X 60 = about three seconds.  The sun would cool down and probably the thermo-nuclear reaction at the center would stop.

This is the green house effect. On the Earth, the atmosphere is transparent to most of the light energy coming from the sun so the atmosphere is heated from below as this radiation is absorbed by the earth.  The warmed earth radiates long wave radiation.   If this long wave (infra-red) energy was radiated at the speed of light straight back into space, the planet would cool rapidly.  If on the other hand, some of the gases in the atmosphere absorb and re-emit the energy coming from the planetary surface in all directions, the planet warms up. It is a fact of nature that the wave lengths of energy coming off the earth, mainly in the infra red spectrum is absorbed and re-emitted by the gases we call green house gases.  They include water vapor, methane, nitrous oxide and a bunch of others in addition to Carbon dioxide.

On earth we have the same phenomenon as on the sun but vastly reduced.  Green House gases in the atmosphere  absorb photons in the infra-red part of the spectrum and re-emit them in every direction.  More of these molecules then do the same.  This delays the escape of heat from the atmosphere and causes it to warm.  The greater the proportion of green house gases in the atmosphere, the longer it takes for the energy coming off the earth to reach space and head out at the speed of light.

As the earth as a whole warms up, it radiates more energy.  Eventually we reach equilibrium with the same amount of energy being radiated as is being absorbed but the Earth is now warmer.

Sunday, December 27, 2015

How to get the beaver back

OK, so you have finally realized that at least a partial solution to your water problems is to get the beaver back in every stream or seep where he can possibly build a dam.  As you have realized, this will shift water from winter to summer (just as snow packs and glaciers used to do), recharge your water table, clean your water of sediment and nutrients, extend the life and effectiveness of your hydro-electric dams, allow these dams to provide more water and more electricity than they are doing now and so forth and so on.  So how do you get the beaver back in your catchments.

First, beavers need trees to build their dams.  Willows are great but any deciduous tree will do.  If you have such areas, capture and transfer some beavers to the area.  release them in lakes, artificially dammed ponds in streams or naturally deep parts of the stream. This will keep them happy as they explore the area and find a suitable location to build a dam.  However, the problem is, that much of the catchment will have been degraded and will be lacking a riparian zone of trees. Let's fix that and spend very little money doing it.

Tools you will need are a chain saw (If you don't like the noise, get an electric one that plugs directly into your specially installed alternator on your pick up truck) a pair of secheters (pruning sheers), a lopper (optional), an axe, a sledge hammer and 5 foot  steel bar sharpened on one end for each member of the crew.

Find a suitable deciduous tree such as a willow, poplar, aspen, cotton wood etc. Cut it down about waste height.  You want to leave a stump to coppice (grow from the stump).  Cut the entire tree all the way from the trunk to the small twigs into fore-arm length pieces.  The pruning sheers will come in handy for the smallest branches.

The larger logs you can leave as-is or split into four.  Sharpen the bottom end of all the larger pieces with your axe.  The thinner branches don't need sharpening.  Bundle all this into your pick up truck, cover with some wet sacks and head for your site.  You must do this when there is some moisture in the soil where you want to establish a beaver friendly riparian* zone.  This might be following a rain which has zoomed down to the sea, taking your top soil with it.  Nothing like watching your top soil disappear to inspire action.

*A a zone of trees and bushes on the side of a stream or river.

At the site, take the sharpened logs and quarter logs and pound them into the ground with your sledge hammer.  For the smaller branches, use your steel bar to punch a hole into the ground.  Try to make the hole about a third as deep as the length of your pieces of branch.  Drop in the branch and heel in.

For the intermediate diameter branches, if the ground is too hard to pound them in, the bar is also useful.  Punch a hole with your bar by ramming it a few times into the same hole,  rotating the top around to widen the hole at each punch.  It is now much easier to pound the medium diameter pieces into the ground.

If you have deer around the place and no wolves to keep them moving, you will have to find some way to keep them off of your new forest at least until it has a couple of years to grow.  Many of the deciduous trees grow at phenomenal rates if protected and soon will be too high for the dear to destroy.

Have fun and make sure to take 'before' and 'after' pictures and maybe write a blog with an article for each site you do.

And what happens if your introduced beavers threaten to flood your house or wash away a road.  Simple. You install a beaver deceiver.   Look them up on the net.  Here is how you make and install one model.

At a convenient place on the dam, remove branches.  Make a depression deep enough so that if the water only gets to that level, it won't cause damage to whatever you are trying to protect.

Get a piece of that corrugated plastic pipe and lay it over the dam.  It must be long enough to reach the bottom of the pond and  to reach the stream bottom on the down side of the dam.

Make up a U of scrap wood and pound it down into the beaver dam, upside down to hold the pipe in place.  The beavers will come and patch up the leak that evening and you don't want them to accidentally shift the pipe.

And the last step. Get some wire weld mesh of the type they use to reinforce concrete.  The bigger the holes the better but not large enough to let an adult beaver through.  Bend this mesh in a circle to make a cylinder and attach the ends together.  On one end, clip out a couple of cross ties all around.  A bolt cutter will do nicely.  You are going to pound this cylinder into the bottom of the pond with the clipped end down and removing the cross ties will allow you to push or pound the cylinder into the bottom of the pond.  The cylinder should extend above the level of the water or you could even put a top on it of mesh* and have it totally under water.  You, of course, are going to place this cylinder over the inner end of the pipe (almost forgot to mention that).

Now no matter what the beavers do, the water will remain at the level you have determined.

* Unprotected steel which is always immersed in water corrodes (rusts) very very slowly so putting a mesh lid on the cylinder and making sure it is completely submersed is not a bad idea.  Besides if you are in an area where the water freezes in the winter, if the top of the cylinder is below the bottom of the ice, it won't be shifted by ice movement.  A bit more work but worth the effort.  Iron corrodes most quickly just at the surface of the water.