Friends of Cabin John Creek board member Roy Seidenstein gathers macroinvertebrates from Cabin John Creek, Oct. 18, 2020. Photo by Burr Gray, FOCJC.

New Bacterial Monitoring Program

We have started a pilot program this summer (2022) testing E-Coli in Cabin John Creek.

Current Monitoring Program


October 2020: We Saw Lots of Biodiversity, but Poor Habitat

The Friends of Cabin John Creek (FOCJC) stream monitoring team spent the afternoon of Sunday, Oct. 18, 2020, catching and identifying macroinvertebrates in the Cabin John Creek mainstem at Cabin John Local Park. As of the latest county reporting in 2015, the Cabin John Creek Watershed was rated "Fair" for benthic macroinvertebrates, fish species, and habitat. The creek suffers from silting, erosion and flooding (check out this video when the creek becomes more of a river!)

Although our biodiversity score was high (see report below), indicating many different types of critters are hanging in there, they were mostly the somewhat-pollution-tolerant and very-pollution-tolerant kind. We were happy to see a pollution-sensitive darner dragonfly and many fingernet caddis fly larvae. The usual suspects included pollution tolerant mayfly larvae, caddis fly larvae, black fly larvae, midges, crane fly larvae, aquatic worms, and sowbugs.

Our habitat score was very low (see stream scoresheet report PDF), indicating poor or stagnant habitat to support the sensitive macroinvertebrates that we'd like to see in a healthy creek. 

Friends of Cabin John Creek has recently re-started our water quality monitoring program under Covid-19 protocols. We work in partnership with Audubon Naturalist Society and follow their protocols. The data is entered into their database that tracks stream conditions in Montgomery County. We just completed our second year of quarterly macroinvertebrate sampling in the creek at Cabin John Local Park.

-- By Greg Gurley, member of the FOCJC Board of Directors


Friends of Cabin John Creek Vice President Sandy Laden used a microscope to identify macroinvertebrate species at the Oct. 18, 2020, water quality monitoring event. Photo by Burr Gray, FOCJC.

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Volunteers from Friends of Cabin Creek and the Audubon Naturalist Society working to identify macroinvertebrates sampled from the creek in Cabin John Local Park in June 2020. Photo by Greg Gurley, FOCJC.

Initial Creek Health Monitoring in the 2000s


In October 2000, Friends of Cabin John Creek began a six-year water quality monitoring program in which volunteers collected and analyzed stream samples from sites throughout the watershed.  Water quality monitoring data can be used to establish a baseline measurement of ecosystem health, identify and prioritize pollution problems, and gauge whether restoration efforts are successful. 


At its peak, the program collected data four times annually at 10 sites with approximately 50 volunteers participating.  Most of the sampling and analysis was conducted using the Izaac Walton League’s Save Our Streams Benthic Macro Invertebrate (BMI) Protocol. Additional measurements included turbidity, pH, temperature, dissolved oxygen, vegetation, and erosion. Monitoring results were submitted to the Montgomery County Department of Environmental Protection (DEP), to supplement their monitoring program, and FoCJC also participated in the Maryland State Department of Natural Resources (DNR) Stream Waders monitoring program.


Monitoring sessions were held on one day during the first three full weekends of the month in May, July, and September,  and optionally in December-February.  Training sessions were once or twice a year for new monitors, but the knowledge can be picked up relatively easily during the sessions themselves.  Data collected by the monitoring program was used to evaluate the health of the creek and to determine whether the County's stormwater runoff control program was working.  Much of the adverse impacts on local streams comes from stormwater runoff.


Powerpoint Presentation on FOCJC Monitoring Program, presented by Roy Seidenstein at the October 27, 2007 Montgomery County Watershed Conference.


Creek Health Monitoring Data

2011-2015 Watershed Health

2000-2006 Monitoring Site Map

2003-2006 Water Quality Data

2000-2003 Monitoring Data Tables


For details, contact