Water Quality Monitoring Programs

Friends of Sligo Creek’s Water Quality Monitoring program includes measurements designed to evaluate and track the Creek’s biological, physical, and chemical health. We post the results of these monitoring efforts here on our website (see below), and regularly share them with government agencies such as Montgomery County Department of Environmental Protection (DEP) and the Maryland-National Capital Park and Planning Commission (M-NCPPC, or Parks.)

  • Our Water Quality volunteer team conducts monthly sampling throughout the year at seven sites along the Creek’s middle reach, measuring physical parameters like temperature, pH and conductivity, as well as pollutants like ammonia-N, Coliform and chlorine. See the Testing Parameters and Equipment table below for details on these parameters. Our monitoring data is summarized on the Water Quality Monitoring Data pages.
  • In the summer of 2020, we began sampling for turbidity, Coliform, and dissolved oxygen levels as part of a regional consortium, the ARK/FOSC Volunteer Water Quality Monitoring program. Led by Anacostia Riverkeeper (ARK), we partnered with ARK again in 2021 and 2022. You can view the results on the ARK/FOSC page.
  • In addition, we partnered before the pandemic with Nature Forward (formerly Audubon Naturalist Society) to help track Sligo’s biological state, keeping track of macro-invertebrates, insects, fish and other animals at our sampling sites on quarterly basis. This was suspended but has now resumed. In Section 1 at the Pepco power line, macro-invertebrate testing started in Spring 2022.
  • Finally, our Winter Salt Watch team tests the Creek and its tributaries for road salt runoff. Visit the Salt Monitoring Initiatives page for details on the program and how to become a Salt Watch tester.
Parks Dept staff in high waders electrofishing with nets in Sligo Creek, August 31, 2021.

Parks Dept staff electrofishing 8.2021

Objectives of the WQ Sampling Program

  1. To monitor the water quality chemistry of Sligo Creek and provide data to the general public and the government.
  2. To bring awareness to Montgomery County and Maryland State governments that we are watching the creek regularly.
  3. To report to the government when there are illicit discharges to the creek and to bring awareness of the need for budget monies to take action.
  4. To accumulate water quality data on Sligo Creek to know if it is becoming better or worse over time.

Testing Parameters and Equipment

Visit An explanation of the definitions of the testing parameters used in this table.

Parameters MeasuredEquipment Used
Temperature, pH, Salinity/TDS/ConductivityExtech ExStik II – EC510
ChlorideLaMotte Smart3 Colorimeter
ChlorineLaMotte Smart3 Colorimeter
SurfactantsLaMotte Smart3 Colorimeter
TurbidityLaMotte Smart3 Colorimeter
Ammonia, Copper, Iron, Nitrate, Nitrite, PhosphorusHach Test Strips
NoiseDr. Meter – MS10
Air QualityHoldPeak HP-5800D
Coliform3M Petrifilm Count Plates
Quincy Lab Model 10-140E Incubator

FOSC 2021-2022 Chemical/Bacterial Water Quality Monitoring Sites

FOSC chemical and bacterial water quality monitoring sites in Sligo

FOSC Water Quality Monitoring Sites
GPS Coordinates

FOSC Water Quality Monitoring sites 2022 with GPS coordinates

Related Program Links