As You’d Expect, Hurricane Irene Drastically Altered Local River Ecology

Kurt Heidinger, Executive Director of Biocitizen School of Westhampton, MA writes:

The past Wednesday afternoon, Biocitizen teamed up with Hilltown Families to do our annual rapid biotic assessment of the Westfield River downstream of the Route 143 bridge in West Chesterfield, MA. Thank you volunteer citizen scientists!

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Before we began, our hosts Sienna and Persephone described how scarily high the river rose during Hurricane Irene. Not only did beautiful farmland across the river crumble—old barn and antique garbage dump included—into the torrent; but they also heard giant boulders rolling, bumping, crashing below the surface. In fact, they could feel the vibrations of the boulders in the foundation of their house (Face it amigos; we’re all on jello.).

A first view revealed just how drastic the re-ordering of the river, and riparian corridor, was. Tree branches high on the bank held fist-sized clumps of leaves and debris, proof the flood crested around 15 feet above its present level, which is itself abnormally high. Down at the river, Persephone (9yo)—and Rowan (9yo), Owen (8yo) and Cyril (8y0)—showed me where her fort used to be (on a sedimentary sand bank). Then we saw all the flotsam she’s collecting to build a new one, on higher ground. I was relieved to see our sampling area was basically intact, and marveled with grim fascination at the look of the whole river course, which appears to have been bulldozed.

We did 6 invertebrate collections, 2 each at 3 sites that are within 20-30 feet of each other. Our first sampling shocked us, because we couldn’t find a single invertebrate; last year, each sample teemed with writhing, boisterous bugs. Below are RBA data sheets for 2011 and 2010 for your comparison. Look at the top row of each to get the basic idea: we didn’t find any large stoneflies this year, only tiny ones. (“The meek shall inherit the earth”…?) As we might expect, we found plenty of worms that build cases and glue themselves to large stones.

So: it was a “bad’ year, if we consider “good” to be finding lots of big juicy stoneflies. But for the purposes of cold-hearted science, the drastic alteration of the riverbed and reduction of the number of bugs is “great” because the bug population will definitely rebound (“no empty places in nature”). The biotic resurgence will be cyclical, though, and might take a year or more. The benthic invertebrates we collect live their short adult life next spring and summer (some live under water for more than one year); the reproductive cycle takes at least a year. There will probably be a lot of hungry trout next summer and perhaps less osprey 2 years from now, as a result.

We look forward to next year’s RBA with anticipation—it will show us how the river is a superorganism whose health changes in response to climatic influences.

And we are pleased to report that, notwithstanding the trauma it has endured, the Westfield @ Rt 143 is a river of “excellent quality” water!