It was a beautiful day for being outside and LFWA’s Stream Monitoring team was excited to be in the water looking for the benthic macro-invertebrates that give us an indication of the health of the Little Falls Branch. The weather was beautiful; the results discouraging. We found only 8 different species of organisms - caddisfly larva, damsel fly nymph, sow bug, aquatic worms, black fly larvae, midges, minnow mayfly nymph, an Asian clam, and sow bugs - putting the creek on the upper end of “poor” for bio-diversity. Unfortunately, we didn’t find any pollution sensitive organism rating our habitat “poor or stagnant”. This is a great improvement over our winter monitoring when we did not find the required 100 organisms needed to assess the stream. However, it is the same as we found in the fall of 2020 and basically the same diversity and types of organisms that we have found since we began our monitoring program in 2014.
What we look for
Using the protocol set by our partner organization, Audubon Naturalist Society, the team searches for benthic macro-invertebrates - the small critters that live on the bottom of the creek or under rocks. These organism are largely the larva form of flying insects you see around waterways. The diversity and number of organisms found help us determine the health of the creek. The organisms are rated by pollution sensitivity and then assigned a score based on the types found.
why our creek is so impaired
The main threat to our creek, and in fact most urban creeks, isn’t chemical pollutants, but stormwater run-off. Our densely populated area is 35 percent or more paved over. Driveways, sidewalks, streets, parking lots and houses are all impervious surfaces which prevent the water from soaking into the ground when it rains. Instead, the water runs off these surfaces into the storm drain system which flows directly to the creek. You can see the concrete inlets as you walk along the banks.
Every time it rains, the water coming into the creek is like a little tsunami; the volume and velocity blowing out the banks, causing erosion and habitat destruction. The dirt from the erosion buries the rocks that the benthic macro-organisms call home. You can tell just from looking at how buried the rocks are that our creek is not hospitable for the little critters. They prefer to live under the rocks not on the sides or top.
what You can do to help
The life of an urban stream is very hard. Besides the flooding when it rains, stream depend on ground water for their base flow. If rain water isn’t soaking into the ground, the base flow of the creek is impaired too. The most important thing that homeowners can do is manage stormwater on their property, so that it soaks into the ground and doesn’t run-off into the storm drain system.
Montgomery County has rebates for residents, non-profits and business for doing stormwater management on their property. Click HERE to learn more about how you can manage stormwater and the importance of getting water back into the ground for our natural areas.
learn more about our monitoring programs:
LFWA monitors four times a year. We also do salt monitoring and keep track of the pH and temperature of the creek. You can see the results from previous monitoring sessions HERE.
Learn about our Stream Team HERE. We are always looking for new members.