Watersheds Messenger     Spring 2002     Vol. IX, No. 1     PDF ISSUE

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Watershed Restoration Requires Beaver Restoration
By Louise Wagenknecht

I live just outside Leadore, Idaho, a stone's throw from the lower reach of Timber Creek, once a tributary of the Lemhi River. The tall old cottonwoods along its banks stand grey and dead. Only a few smaller trees and sprouts manage to eke out a living from the water that is allowed to flow downstream between the end of the irrigation season in mid-November and the last pulse of high water in June.

That is little enough, since Timber Creek's water is diverted onto agricultural fields as soon as the thaw comes and long before the growing season starts.

This land is a high-elevation desert. Only 8 or 9 inches of precipitation per year fall on the valley of the Lemhi River in a "wet" year. The melting snow on the high mountains on either side of the river has for many millions of years sent sediment pouring into the streams to be flushed out of the river system. And for many millennia, much of that sediment was trapped and held within the Lemhi River's watershed by the actions of a large, industrious rodent driven by instinct to build dams of mud and sticks and to live protected in lodges built in the resulting reservoirs.

Beaver made the riparian areas of the Lemhi River. Whatever soil now exists in the floodplain is their doing, the result of the silting up of successive generations of ponds on side channels and their slow change from pond to swamp to meadow or cottonwood grove. But beaver no longer build dams on the Lemhi River, and all the soil they conserved. is leaving us, year by year, torn away by plows and the hooves of cattle.

In the waning days of 1830, a Hudson's Bay Company expedition camped near Timber Creek. The expedition's leader, John Work, described Timber Creek as "a small poplar river which falls in from the Southward . . . here the [Lemhi River] runs through a swamp . . . Formerly beaver were very numerous and there are still a few both in the main river & the streams that fall into it."

Beaver were being trapped out of Idaho. While camped near what is now Challis, Idaho, on Oct. 25, Work wrote, "19 beaver were taken, which the men reckon few considering the number of traps set and the good places at which they were removed the willows that once covered it. In the early spring, before the grasses try to grow once more, vertical banks of bare soil can be seen from the highway, sloughing away inexorably under the weight of thousands of shearing hooves.

In Work's day, the policy of the Hudson's Bay Company and of the British government itself - was to keep the United States out of the Oregon Country by turning it into a "fur desert." No beaver, no Americans, the company reasoned.

When the market for beaver pelts collapsed in the late 1830s, many beaver populations in what is now Idaho had been exterminated. Here began the long process of watershed degradation that continues today, as beaver dams began to wash out, untended.

Beaver populations were still only a shadow of what they had been when white settlers moved into the area in the late 1860s and immediately declared war on beaver, both for the money to be made from their pelts and their habit of blocking irrigation and mining ditches. The war continues today.

A few years ago, I attended an irrigation district meeting at which several ranchers talked openly of their plans to kill beaver on the upper reaches of Timber Creek. Tearing the lodges apart with a backhoe and then shooting the fleeing beavers was the best method, one rancher said. Another recommended dynamite. It is an article of faith with them that beavers are taking "their" water by holding back the spring runoff.

Ironically, some of those same men are now supporting a study for a possible dam on Timber Creek, which if built would cost the taxpayers $20 million to 30 million to impound a mere 600-1,200 acre feet of water.

How ironic that a few colonies of the very beaver they are so eager to kill could do the same job for free: holding back snowmelt from the Lemhi Mountains, gradually releasing it to cool the waters of the Lemhi River late in the summer, just when native trout and returning salmon are most in need of it.

The healing of the West's watersheds will require not only the removal of cattle, but also the restoration of this keystone

As his party of about a hundred men, women, and children traveled up the Lemhi, they took only 42 beaver, despite the good habitat: "The banks of the river flat and in places swampy and well wooded, principally with poplar and willows." Work's trappers "complain of a great scarcity of beaver considering the fine appearance of the river for them, and the numbers which were formerly found in it."

The swamps that Work wrote of are gone now, plowed for crops of barley and alfalfa, drained by irrigation ditches, grazed into alkali-rimed hummocks by cattle.

Just north of Leadore, a swamp that Work mentions is now grazed yearlong by many cattle, whose mouths and hooves have

Louise Wagenknecht is a WWP board member.


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