www.charlescountymd.gov

Charles County, Maryland

Watershed Health & Monitoring

Watershed Health & Monitoring

Watershed protection and pollution prevention help secure our quality of life, maintain a clean water supply, and provide healthy living environments for humans and wildlife.  Reducing pollution through prevention also reduces the need and cost of watershed restoration efforts.

Per the requirements of the County’s NPDES MS4 Permit, pre and post rain event stream monitoring is required on a continuous basis.  The County monitors the biological, physical, and chemical health of our waterways to assess watershed health and prioritize watershed restoration efforts. 

Biological monitoring - Bugs in our streams are good indicators of pollution because they live in streams and cannot travel far to escape pollutants.  Some water bugs, called macroinvertebrates, are pollution tolerant and can live in somewhat polluted streams, while others are pollution sensitive and are only found in cleaner streams.  Collecting macroinvertebrates from streams, separating them by type, and using the data to measure stream health is known as a Benthic Index of Biotic Integrity (BIBI) score for each stream.  The scores range from 1.00 (poor) to 5.00 (good).  

Physical monitoring – A geomorphologic stream assessment is used to measure physical stream health.  The annual assessments include comparisons of permanently monumented stream channel cross-sections, comparisons of the stream profile, and stream habitat assessments using techniques defined by the EPA’s Rapid Bioasessment Protocol for use in Wadeable Streams and Rivers.  Rainfall effects including discharge rates, are measured annually using hydrologic models. 

Chemical monitoring -   Chemical monitoring measures water quality by taking samples during rain events to collect the rising limb, the peak, and falling leak of the storm flow.  Chemical monitoring measures levels of the following:

  • pH
  • water temperature
  • Biochemical Oxygen Demand (BOD)
  • Total Kjeldahl Nitrogen (TKN)
  • Total Petroleum Hydrocarbons (TPH)
  • Total Copper
  • Total Zinc
  • Total Suspended Solids (TSS)
  • Oil and Grease (optional)
  • Total Cadium
  • Nitrate Plus Nitrite
  • Total Phosphorous
  • Total Phenols
  • Fecal Coliform
  • Total Lead

Acton Hamilton Restoration Monitoring
The Acton Hamilton subwatershed is located in Waldorf on the southwest corner of the Route 301 and Acton Lane intersection.  It is a subwatershed of the Mattawoman Creek watershed that is impacted by 33% impervious cover, where only 44% of the stormwater runoff is managed to current standards. 

Charles County began biological and physical monitoring at this location in 2005, and in 2015 added a chemical monitoring station to determine if water quality improvements can be identified, once 75% of the stormwater runoff is managed to current standards.