posted 11 years ago
Using Beavers to Store Water and Dodge Water Catchment Laws.
Beavers were once an integral part of ecosystems where they are now absent. They were responsible for water management, soil creation and erosion control. Before the fur trade extirpated them from large areas, movement of water through those watersheds was slowed. Their ponds and meadows captured spring melt water and water from heavy rains. Spring flooding of rivers was less severe at that time and water tables were higher since the water had more time to soak into the ground. Fish lived in these ponds and congregated there when river levels were low. Ponds that filled with sediment over time became rich meadows. In times of drought, people and wildlife relied on the lush areas around ponds and on the natural springs that flowed downhill from them. Many streams that are now seasonal, had some flow throughout the dry summer. Las Vegas didn't exist, and therefore had no claim on water that these ponds trapped.
.......
Beavers are a very destructive animal. I would never introduce them into a lush environment where they could easily get out of control. For most of us, the arrival of beavers would be a real concern, since they are hard to capture and they breed quickly. In areas that are quite dry, introduced beavers would be somewhat land locked. They would be totally dependent on the water source that they occupy since migration over dry land is fraught with hazards. They would become a free range farm animal, as dependent on your man made patch of trees as chickens are on their coop. Their numbers would need to be controlled to match available food. Fruit trees and bushes would need to be protected from them.
Beavers can be useful creatures in areas where it is necessary to impound water, but the water does not legally belong to the land owner. This is the case for much of the watershed of the Colorado River. The water falling on your land may legally belong to California or Nevada. Beavers are by no means rare, but they have been extirpated from some areas and sometimes enjoy legal protection. The water cops would be pitted against endangered species legislation, should it ever be decided that you are storing too much water. If swales were constructed near a gulch, they could trap enough water to grow cottonwoods, alder and other prime beaver food/building materials. Introduce beavers during the wet season and allow them to build dams. You could make a start for them, so that dams are properly situated. Over time, a family of beavers will produce an enormous change in the landscape and they'll maintain it all for free. Culling is absolutely necessary in areas that lack predators. Grizzlies sometimes catch beavers, coyotes and domestic dogs aren't so successful.
On land that has enough variation in elevation for key line systems, it would be good to have one pond near the top of the property and others spread down slope. On very flat land, a beaver pond will tend to overtake prime agricultural areas and prevent desired drainage. I would prefer to see them occupy limited areas on slope that are separated from gardening activities in distance and elevation. Drinking water and beavers are not compatible due to beaver fever, but hopefully the key line will produce springs that deliver potable water.
Ponds fill with sediment over time. Soil is built up faster in a rich aquatic system than it is on land. Dredging could get this soil onto crops or the pond could be drained and the beavers moved down slope to a fresh batch of little trees. This is what nature does. I've traveled rivers in Canada's boreal forest where hundreds of years of succession is evident. Ponds become bogs, bogs become groves of black spruce and later birch and pines. Leaf drop from the broad leaf trees around ponds could contribute further nutrients and water holding capacity to degraded lands.
This sort of plan would be best done on a large, inexpensive acreage in a zone that is too dry for beavers to naturally spread to neighboring properties. Cottonwood and alder would make fast growing forage for them. These trees will also consume a good portion of the collected water and create a moist micro climate in their midst. Suppose we have 100 acres of marginal land that gets 15 inches of annual precipitation. It might make sense to use most of it as natural catchment and only grow useful things on a few of the lower acres. Much of this land produces nothing' agriculturally speaking, so if only 5 - 10 acres of the lowest part of the property were well watered, that would be a vast improvement over the current condition.
Beavers invented hugelkultur. Some garden plants are likely to do just fine around a pond and on the dam, and some won't. Beavers will eat or destroy many plants. Most trees are at risk when beavers are present. If a pond were drained and the beavers were moved to a new location, the dam and lodge could be converted to hugelkultur. The bottom muck would be the richest soil you'll find. Once the beds rot down, scrape up the best soil for use elsewhere on the farm and bring the beavers back to do it again. A rotation like this could go on indefinitely.
Since a beaver managed water system is reliant on trees, it would need to be started a few years before beavers arrive, to give trees a good start. The swales and other earth works would become well established in the interim and any springs thus created would have time to develop and be discovered. Beavers will utilize wood that is brought to them. A new forest constantly requires thinning or it will thin itself. If these trees are dragged to the pond, the beavers will use them and cut down fewer trees. Even in dry regions, there are often wet areas around rivers which are logged. Slash from these areas could be brought to the beavers whenever you want to reduce pressure on your own groves.
I'm going to do some further research concerning the legal status of beavers in different regions and on the laws which prevent farmers from trapping rainwater. It would take some management for sure, but this seems like exactly the sort of gray area that would keep the water cops at bay. It seems like an issue that could be rightly wrapped in the greenest of green flags. We're reintroducing a species that was once common before they were hunted to the brink for their pelts.
It's not often that I advocate for something as politically correct as this. There's wildlife, new forests, sunshine and rainbows. If you live in Las Vegas, it's time to xenoscape the lawn. The people up north are starting to view their marginal lands as more than a giant tarp meant to send rainfall in your direction. (yeah, that sounds more like me)
Do any of you know of farms that make use of beavers in this way ?