EPA Study Examines Wadeable Streams

One of the fond memories of my childhood was hunting for crawdads in the little creek that ran through our farm in the Ozarks.

One of the fond memories of my childhood was hunting for crawdads in the little creek that ran through our farm in the Ozarks. My brothers and I could spend hours wading in the cool, clear water of the creek on a hot summer day.

One stretch of the creek included large, flat rocks each measuring several feet across. During the summer, when the water level was down, the creek divided itself into several narrow channels that meandered through the rocks. That section of creek was filled with hundreds of crawdads (also called crayfish by some folks) that lived in the crevices and tiny caves under the rock slabs.

A string with a small piece of bacon made a great “fishing” tool. Lying on our stomachs atop a shade-covered rock, we would lower the string into the water, dangling the bait in front of a crevice. In no time at all, a crawdad would crawl out and grab the bait. Once their claw clamped down, a quick jerk of the string brought them flying out of the water before they could let go.

It was great fun for young boys on a sunny summer day.

I’m sure young boys still enjoy wading in rural streams across our nation. But it might not be the best pastime in some regions of the country.

A recent survey of “wadeable” streams - streams shallow enough to sample without boats - found that only 28% of stream miles in the US were in good condition when compared to the best available reference sites in their regions. Another 25% were in fair condition and 42% were in poor condition. Another 5% were not assessed.

The Wadeable Streams Assessment (WSA) was EPA’s first statistically valid assessment of small streams. The sampling began with pilot work in the West in 2000 and was completed nationwide in 2004. A draft report on the project is available for public review and comment at http://www.epa.gov/owow/streamsurvey.

The survey found that stream conditions vary widely across the country. Of the three large climate and landform regions studied, the West is in the best condition, with 45% of the length of wadeable streams and rivers in good condition. In the Eastern Highlands region, 18% of stream length is in good condition and more than half is in poor condition. The quality of streams in the Plains and Lowlands region falls between the other two, with almost 30% of stream length in good condition and 40% in poor condition.

The WSA measured key chemical and physical indicators that reveal stress, or degradation of streams. The most widespread stressors observed across the country and in each of the three major regions are nitrogen, phosphorus, streambed sediments, and riparian disturbance (human activity alongside streams, such as pipes, pavement and pastures).

The study was designed to establish a national baseline and will be used to evaluate the successes of national efforts to protect and restore water quality. It is part of a series of studies planned by EPA that includes examination of coastal waters, lakes, large rivers and wetlands.

James Laughlin, Editor

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