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The blonde color between cobbles and gravel on the bottom of the Trinity River shown in the photo is caused by decomposed granite sands. Before the dam, spring flows or natural floods would tend to flush and down stream. The machine in the center of the photo rips the gravels mechanically. These measures were only used for a short while and found to be not cost-effective. Photos provided by the Bureau of Reclamation.


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The gravel ripping machine is flushing sand out of a prime spawning riffle. The tan colored water below the riffle is the sand which is being flushed down stream. Unfortunately, these measures brought only very temporary relief because sand re-intruded in gravels with the next high river flows. Photos provided by the Bureau of Reclamation.


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The tracks where the gravel ripping has occurred are evident as trails of clean gravel after the machine has made only one pass. Photos provided by the U.S. Fish and Wildlife Service.