Small streams make a big difference
|August 2, 2017 - Tributaries, like the Arroyo Seco, feed the larger rivers. They are an essential part of the river system, but Trump Administration proposals to undermine the Clean Water Act could severely damage tributaries as well as major rivers. -|
We love our big iconic rivers: the Snake, the Rogue, the Umpqua, the Klamath, the Gunnison, the Madison, the Salmon, and the Henryís Fork to name but a few. These waters invoke passion among anglers, river runners, and all those who appreciate the beauty of wild, clean rivers.
But just like anything else, these big rivers are formed from smaller parts. Each of these rivers is fed by small tributary streams far in their headwaters. Small streams continue to add vital flows, nutrients, woody material, and gravels to the larger rivers as they head downstream. This dependence of the big rivers on the smaller streams is an important one, not only for hydrology and flows, but also for the ecology of the river, the health of fish populations, and the prosperity of nearby communities.
Ironically, the importance of these small streams seems lost in the debate about proposed changes to the Clean Water Act. Why worry about protecting small streams? Trying to protect our big rivers without protecting their tributaries is like trying to control your weight without watching what you eat. Itís all about the inputs.
Stand up for Clean Water
Letís review some of the values of small tributary streams to their larger rivers.
The condition of tributary streams determines their ability to provide the benefits described above. Habitat complexity Ė especially inchannel complexity provided by large wood, boulders and gravels -- is very important to maintaining values in tributary streams. So are clean water and healthy riparian habitats.
Dredging, channelizing, removing instream structure, introducing pollutants, and loss of riparian vegetation are the most common causes of stream degradation. The most recent National Rivers and Streams Assessment conducted by the EPA reviewed data available from 1.2 million stream miles from smallest headwater streams to largest rivers. The EPA found that 46 percent of our nationís streams were in poor biological condition, 25 percent in fair condition, and 28 percent in good condition.
What were major drivers of poor stream condition? More than 40 percent of streams had nutrient pollution problems, 24 percent had poor quality riparian vegetation, 20 percent had high levels of riparian disturbance, and 15 percent had excessive fine stream sediments. These drivers of reduced stream condition are exactly the kinds of problems that can be addressed by protecting our tributary streams through the Clean Water Act.
As the Trump Administration continues its rollback of rules and regulations that protect our water quality it might be wise to remember where our big rivers come from and what makes them so important to all Americans. Itís all about the inputs.
Jack Williams is the senior scientist for Trout Unlimited
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