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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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 Starting the invertebrate tabulation while bug picking continues on the table. |
December 9, 2023 Stream Monitoring: The weather was sunny and a bit on the cool side today, with temperatures rising to about 50. Our catch today was dominated by aquatic worms and netspinner caddisflies, species that are tolerant of impaired waters. We did catch a single mayfly, a species that prefers clean water. If only we found more mayflies, we might be able to believe the health of Accotink Creek was showing sins of improvement.
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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After weeks of hot weather without any rain, we were worried we would not find any streamflow at all. However, overnight rain raised the water level to where we could place our collection nets without problems. The heat wave relented as well, giving our crew of ten volunteers comfortable working temperatures around 80 degrees.
Our monitoring today produced a stream health score of 3, below our usual average, and outside the acceptable threshold of eight on the 0 - 12 scale. See the tabulated results here. The most unusual invertebrate we encountered today was not found in our nets, but was a caterpillar of the Banded Tussock Moth that came wandering by as we were counting the aquatic invertebrates. |
Everyone got into the water today. |
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June 24, 2023 Stream Monitoring: Continuing rainshowers for several days sent the creek to levels too high for sampling overnight, but by the time we arrived we were pleased to see the water had receded just enough to permit us to work. We were fortunate to catch the full quota of over 200 invertebrates with just one net today, just as also happened last June. 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 a single caddisfly which was not a Netspinner, and a single Riffle beetle larva. These are species require better quality water and which we hope to someday see in larger numbers. Accotink Creek achieved a stream health score of 5, outside the acceptable range on the scale of 0 to 12. See the tabulated results here. |
 Littlest volunteer can barely see over the table, but still spotted a lot of bugs. |
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March 11, 2023 Stream Monitoring: We had a crew of 12 volunteers today. The weather was favorable, sunny and calm, with temperatures rising to 46 degrees. Accotink Creek was a bit high rain the previous day, but not to high for us to carry on. We needed to set the maximum of 4 nets to collect the minimum of 200 invertebrates for a valid score. The last net was the most productive. We should have tried that spot first. Our catch today included a single scud, a shrimp-like crustacean, and one we've not seen for years. Otherwise, was overwhlmingly dominated by midges and aquatic worms, borth tolerant of water quality impairment. Accotink Creek received a poor numeric stream health score of 5 on a scale of 0 to twelve. This is what we've come to expect at this location, usually 4, sometimes 5, sometimes 3. 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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Our attention was diverted for a time by mounds of white foam floating along the creek. Foam in streams can sometimes be a sign of contamination, but this was a natural product of bacterial interaction with sediment.
We needed the full allotment of four nets to collect the minimum of 200 invertebrates required for a statistically valid sample. After our final count came up short at 198, we scoured the nets again until we found enough to put us just over the top, at 201.
