Stream Monitoring on the NW Branch
Text and Photos by Anne Ambler (except where noted)
Have you ever wondered just what is involved in stream monitoring? For instance, what is monitored, and how is it done? And of course, what does it all mean? One can test water for nutrients and pollutants, but living organisms can also be checked to determine the current quality of the water and the trend over time, since some organisms are able to survive better than others in degraded water. Come along with the Neighbors of the Northwest Branch team as it returns a second time to its macroinvertebrate monitoring site on the Northwest Branch.
July 18, 2010. The stream monitoring team arrives at the chosen site a little below
the Old Randolph Road bridge, on the west bank of the Northwest Branch.
There's much unpacking to do.
Gretchen Schwartz explains a fine point to Katie Basiotis and Glenn Welch.
The table is set with tubs, gloves, two microscopes, cube trays to hold
individual invertebrates, cups, bags, and the record book.
The record book includes a satellite photo of the Northwest Branch to indicate
the location of the monitoring site.
Jewel Barlow takes a moment to relax before the work begins.
Phillip Capon and Charlie Dorian test the waters first for pH level.
The stream has returned to a more normal slightly alkaline pH of 7.6.
Bel Pre Creek appeared in the spring to have been responsible
for the passing high alkalinity, so it will be watched in the future.
Following the Audubon Naturalist Society protocol, the team must determine 20 places within the 75-meter site to collect samples. Charlie points out the places here that provide the best habitat for macroinvertebrates. In Piedmont streams, these will be
riffles, woody blockages, leaf packs, and undercut banks.
Gretchen and Katie take to the water.
In this business, one is unlikely to avoid getting quite wet.
But when the air temperature is 98 degrees, there are worse things!
The first catch is a crayfish, here confined to one of the white basins.
Back into that riffle again, now Gretchen and Katie have found...
...a mystery worm, somewhat defunct, displayed on Charlie's hand.
Maybe a land beetle larvae? Drowned? If you can identify it, please let us know!
Meanwhile, near the far bank of the stream, Glenn, Jewel, and Phillip are panning for....
not gold, but tiny life.
So it seems strange that Glenn appears to be describing a huge fish he just caught!
But no, he's merely emptying the water out of his gloves. Occupational hazard.
In reality, what they caught was small enough to require the microscope:
a small minnow mayfly.
Photo by Glenn Welch
So... judging from the macroinvertebrates found today, how good or bad is the water? Well, since we only found a couple of bug types representing the three groups we'd like to see that would indicate good water quality, we know the water quality is not very good. So there is a lot of room for improvement. With the renewed push to clean up the Anacostia River and regulations requiring more infiltration of rainwater soon to go into effect, there's hope for improving our Northwest Branch!