Using Doodle Polling we determine a day and time at least four us an can volunteer for a few hours four times a year, winter, April, July and Oct. If you would like to observe, please contact Glenn.Welch@yahoo.com.
In pairs, using a net, we disturb the stream bed and collect in our net whatever floats in. We take 20 net collections and transfer what we find to a small tub.
Any small animal without a backbone that we find on the bottom (benthic macro invertebrate) we examine and identify it. We determine how many individuals of each type we find. We stop when we reach 100.
There are three orders of insect larva that when present can indicate a healthy stream, these are mayflies (pictured), stoneflies and caddisflies.
We of course find crayfish, and larval forms of dragonflies, damselfies, beetles, true flies and others. We count and tally them all.
Currently the health status of streams in lower Montgomery County is not good as they are in the fair to poor range. Our mission then continues to be to improve the overall health of our streams.
Collecting invertebrates from the stream bed.
Wow ! A dragonfly larva
NWB is still the best of the bunch, but not as good as 2 weeks ago.
It's so nice seeing that green bar for the NWB!
Unfortunately, the NWB didn't pass this time, but is not as bad as the others. Bear in mind, of course, that the others feed into the NWB downstream from Burnt Mills.
Sad not to see a green bar--or at least a yellow one--for the NWB. That's what heavy rain does--washes a lot of nasty stuff straight into the NWB, probably mostly by-passing the riparian buffer.
The site at Burnt Mills definitely suffered from the storms of the previous 2 days. Our usual site was somewhat under water, woody debris was piled against the rocks, and plastic trash was everywhere.
The super high bacterial level--off the chart--makes one wonder about possibly septic or sewer contamination. We had been a little spoiled by that green bar earlier in the summer. Now it's ALL red.
We were surprised the results were so bad because Wednesday morning when we scooped the sample, the water appeared to have settled down following the heavy rains of a few days before.
NOT liking that tall red bar for NWB2! How could Sligo Creek, with all the hard cover in its watershed, be better than the Northwest Branch?
Once again, the Northwest Branch fails dramatically, while Sligo Creek is pretty decent. How to explain it?
While this is a little better (lower) than last time, it is not at all good.
We PASSED at last! But this was before the rain. If you are interested in some of the other measures taken, see the ARK water quality portal here.
It is really a mystery how NWB-2 came out so well this time relative to Sligo Creek, and so poorly the previous two times.
The water was very calm. We collected our samples while crouching on the sand bar at the right edge of the picture and on the adjacent rock. Analysis showed our E-coli counts to be just 36.9 and 38.4 mpn/100mL, the lowest by far of the 5 sites sampled. (The other sites are on Long Branch and Sligo Creek.) If the E-coli level stayed like that, swimming would be safe. But unfortunately, after a rain, E-coli levels rise. 5/19/21
Perched on a rock, Anne shows the turbidity sample. We also check the acidity level and water temperature vs air temperature. Sampling will continue every 2 weeks, and at the end of the summer we'll have a profile of stream quality. 5/19/21
Bacteria samples must be kept on ice and analyzed within 5 hours from collection, so it's a race against time to turn in the samples.5/19/21
That's a thermometer she is holding over the water. 6/2/21
The water turned out to be a shade warmer than the air. Perhaps hot water running off pavement? 6/2/21
The bacteria sample must be analyzed within 5 hours, so the label must have time as well as date. The e-coli level, averaged between 2 samples, was 249 MPN/100 mL, still passing, but higher than on 5/19. 6/2/21
Monitors also must fill out a chain of custody form. 6/2/21
They compare the pH strip color to the coding. The water was more alkaline than at the testing 2 weeks earlier. 6/2/21
After a dry period, the e-coli level at our monitoring site was very good. Kem holds the monitoring kit with ice packs and the clip board for recording our data. 6/30/21
Anacostia Riverkeeper's grant provides for testing on 3 sites on Sligo Creek and 1 on Long Branch in addition to our site at Burnt Mills. This map shows the locations of the sites, with colorful e.coli results.
These results for the NWB are very good-just 95.9 mpn/100ML.
The weather had been dry, so road runoff was greatly reduced. But Sligo Creek still suffered, and of course it feeds into the NWB, which may explain why our E.coli readings farther down the NWB last summer were bad.