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Tales of Stream Monitoring Fun
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Friends of Accotink Creek and Friends of Lake Accotink Park hold biological stream monitoring workdays four times per year. |
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 A visit from the Christmas Angel Mussel |
December 10, 2022 Stream Monitoring: The weather was overcast, but seasonably cool today, with temperatures in the mid-forties.
A highlight of our catch today was an unusually high number of 7 hellgrammites. These ferocious predators, up to four inches long, need to be kept in separate compartments to avoid battles to the death. We've been monitoring this same spot for years, but this is the first time we've seen the Beautyberry showing off its deep blue fruits. Unfortunately, this appears to be an Asian species, likely callicarpa dichotoma. We were visited by a spirit of the Christmas season, the open shell of a freshwater mussel, whose pearly interior suggested the wings of an aquatic angel. Too many of our freshwater mussels in Accotink Creek have gone on to become angels before their time, as their populations have dwindled. Read more about freshwater mussels. Accotink Creek achieved a numeric stream health score of 3, down in the unacceptable range. Sediment caused by excessive runoff from paved surfaces is the major factor reducing invertebrate populations and impairing the health of streams in our region. See the tabulated results here.
Paved surfaces are the nemesis of Accotink Creek's benthic invertebrate population. Take advantage of financial incentives to become part of the solution with Conservation Assistance.
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September 10, 2022, Stream Monitoring: Our crew of six volunteers enjoyed splendid monitoring weather, with clear skies and temperatures in the low seventies. Stream flow was also optimal, running a bit below normal with clear water. Hellgrammites were unusually common in our catch today, with a total of fifteen caught. Of course, far more abundant were the aquatic worms and netspinner caddisflies that typically dominate our catches. These organisms are tolerant of poor conditions, so finding too many indicates a low quality aquatic habitat.
Something quite unusual we encountered in the water was a freshly deceased juvenile American Eel, about seven inches long. These creatures are known to be present, but are seldom encountered, being nocturnal and prefering to remain hidden among the rocks. 
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 A fine day on Accotink Creek |
 Looking for every last bug |
June 11, 2022 Stream Monitoring: A light drizzle was with us for much of the morning, but otherwise conditions were good with mild temperatures and the creek running at an optimal level. We were pleased to catch the full quota of over 200 invertebrates with just one net today. It's been almost three years since the last time we were able to do that. The species we caught today were overwhelmingly dominated by Netspinner caddisflies, a species tolerant of impaired water, and the one we catch most often (though not in such a huge proportion). We caught 80 caddisflies which were not Netspinners, the most ever at this site. This is encouraging because these other caddisfly species require better quality water. A first for us today was a single alderfly larva. ID was a bit of a challenge, as we could not seem to magnify it to a satisfactory level of detail, but its little snapping jaws were clearly indicative.
Double sixes! Accotink Creek achieved a stream health score of 6, the same as last time. |
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March 26, 2022 Stream Monitoring: We were guests at the Country Club Hills stream cleanup today and conducted biological stream monitoring by request. The weather was unsettled early spring, ranging from sunny and mild, to overcast, to a few flakes of fast-melting snow. Our catch today had a high percentage of caddisfly larvae, a species intolerant of impairment. The largest percentage of the catch by far was made up of much more tolerant midges, an indication of subpar conditions for aquatic life. Accotink Creek received a poor numeric stream health score of 4 on a scale of 0 to twelve. . See the tabulated results here. | |
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March 13, 2022 Stream Monitoring: We had a crew of 14 volunteers today, including members of Cub Scout Pack 187. We had been forced to postpone our session from yesterday, when blizzard conditions proved too challenging. The weather was more favorable today, cold, but sunny and calm, with temperatures rising to 40 degrees. Accotink Creek was a bit high with snowmelt runoff, but we were still just able to set our nets. The abundance of invertebrates was not impressive. We required three nets to collect the minimum of 200 invertebrates for a valid score. Our catch today had a high percentage of caddisfly larvae and riffle beetle larvae, both species intolerant of impairment. The beetle count was multiples of what we've seen before. Accotink Creek still received a poor numeric stream health score of 6 on a scale of 0 to twelve. We did have a moment of excitement when we thought the score was 7, on the cusp of exiting the unacceptable range. Just a few more caddisflies would have made the difference. See the tabulated results here.
Paved surfaces are the nemesis of Accotink Creek's benthic invertebrate population. All the runoff during rainstorms pours down storm drains and shoots into the creek, scouring away the banks and smothering stream life in fine sediment. The sediment-generating activities of the I-66 project are exacerbating the situation. Take advantage of financial incentives to become part of the solution with Conservation Assistance.
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Accotink Creek Creatures
A lament for aquatic invertebrates penned
GET YOUR BRAIN WET!
Plan now to volunteer again with others to preserve our oceans and waterways Back to our main Monitoring Page
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The bit of luck we had with hopeful scores of our last two monitoring sessions ended, as today's roll of the dice produced a stream health score of only three, quite low on the 0 - 12 scale. 
These numbers are better than our usual scores, but still outside the acceptable range on the scale 
