The Current Magazine Summer 2018 - Page 10

RESTORATION

California's premier spring-creek destination

Success was immediate. Hat soon became California’s premier spring-creek destination. Fly shops opened in Burney and Fall River to serve visiting anglers. From the 1970s into the 1990s, Hat was the place to challenge oneself on the most demanding trout in the state. The creek was rich and weedy, with 16 fishable hatches. The trout numbered over six thousand per mile, mostly Pit River rainbows and a smattering of brown trout. During the 1970s, the catch rate was nearly ten thousand fish per year. Virtually all these fish were released.

In the 1980s, plumes of gray sand began to appear in the flats below the Powerhouse 2 Riffle. As the sand moved downstream, it buried plants and filled in the deeper parts of the creek above Carbon Flats, destroying habitat diversity. The fish were pushed downstream, and spawning declined. Fishing success and satisfaction declined, as well.

The original restoration in 1968 had proved the concept that an intact stream, carefully managed for wild trout, could provide a quality angling experience. This time around, the challenge was very different. Hat Creek was no longer intact. The sediment — over fifty thousand cubic yards of volcanic ash, enough material to cover a football field to the very top of the goalposts — was composed of the ash and fine materials from the eruptions of Mount Lassen that began on the afternoon of May 22, 1915. That epic blast sent a hot slurry of ash, mud, and water flowing nearly thirty miles down the Hat Creek Valley, burying farms and killing fish.

In the years since the eruptions, the valley has been in a slow process of recovery. The spring flows of Hat Creek, Lost Creek, and Rising River have slowly reestablished their streambeds, moving the volcanic ash downstream to settle out in the slow, deep water in Cassel and in Baum Lake, just upstream of the Wild Trout Area.

This process was stable for many decades. In the 1980s, all that began to change. While the dynamics are not entirely clear, it appears that sinkholes and lava tubes under Baum Lake had been slowly filling with sediment since the eruption. These were unexpectedly flushed out during construction work on the Baum Lake dam, immediately above the Wild Trout Area. This material, hundreds of times greater than Hat’s moderate flows could move quickly, overwhelmed the flats, burying everything as it went, covering plants and spawning areas, destroying insect habitat, and displacing trout. The creek became shallower. The bottom became as featureless as a beach. The fish had less and less suitable feeding and holding water. Fish surveys in the 1990s counted fewer than 2,000 fish per mile.