Carolyn Miller wrote:
It's now getting ridiculous, I have to pull out their new construction every 2 days. If I don't the pond will dry up as the exit dam has a few leaks at the base, plus evaporation takes its toll. I can see the water level drop about a foot in a day when the beavers block the inlet. So does anyone have a good method of keeping the inlet open?
Maybe this is a mixed blessing, and you can use Principle 12 to "creatively use and respond to change"?
More water stored uphill is generally a great thing from a permie perspective. Especially if it is created with free labor! I have beavers and I am hoping they'll work just a little higher each year in my own landscape in order to assist in future gravity irrigation possibilities, by building new ponds in the landscape for instance.
Other thoughts to help prevent worrying:
If the watershed's water source (input) is fairly constant, then all the water that the beavers are impounding upstream has to go somewhere, right? I would think that it must eventually saturate into the landscape and then run down the watershed into your pretty pond, and/or evaporate or transpire off. So I would think that, eventually, after the beavers have sufficiently started their new pond, your current pond will naturally rehydrate again. They may also make natural fish passes if you are lucky.
But from a system perspective, focusing on fixing the outflow (the leak) and resiliency may be more beneficial in the long run than focusing on the inflow side.
1) Keeping the fish alive.
2) Fixing the leak in the pretty pond.
3) Mitigating inlet flow to ensure 1 and 2, to get a pretty pond.
For Goal 1, perhaps now is a good time to assess whether there are sufficient (long term) deep water kettles and temperature havens in case of drought?
The PaDM shows examples in Chapter 13, Figures 13.5&13.6
Perhaps a small backhoe could dig fish refuges and disturb and distribute the clay closer to where the leaks are?
An aeration plan could also mitigate and give you more time for a long term fix if the water level gets dangerously low.
For Goal 2, Geoff Lawton had a video or two on using ducks' manure to fix a leaky dam. I think pigs and cows have been used in other videos to help with the gley.
So perhaps if you have animals, you could let them manure the pond and increase compaction at the dam as the water level drops.
Maybe now would be a good opportunity to focus on the downhill side of the dam to see if it needs some vegetation maintenance?
Perhaps there is a sector with evaporative warm winds and sun, which may be better blocked with trees to reduce evaporation?
For Goal 3, to buy you time, and depending on the height of the impounded uphill water, rather than destroying their work, consider jamming some long metal conduit or piping through the lower half of the beavers work to get a slow leak going. As other permies have noted, extending piping (plus exclusion devices) further from the dam is best, and expect the beavers to put sticks and mud into and around any piping. Make it hard for them to do so using wire netting or hardware cloth cage. You could also consider getting a super long flexible pipe and go way further up the creek to help bypass their system. When you are ready to get the water flowing after making fixes downstream, then just lower the uphill pipe.