Understanding Water Quality Science

Addison County River Watch Collaborative focuses on a limited set of chemical and physical characteristics of our flowing waters – measurements of which are called “parameters.”

Water Monitoring Parameters

Phosphorus is one of the most important parameters we sample for. It is one of our most significant parameters because all of our streams and rivers eventually flow into Lake Champlain, a lake that is considered impaired by phosphorus pollution. In recent years the public as well as federal and state agencies have become increasingly concerned about phosphorus entering the lake because it is a nutrient that leads to algal blooms, some of which are toxic. Another nutrient we sample for is nitrogen. Nitrogen in excessive quantities can also cause problems in rivers and receiving lakes.

We also collect samples of water – in special hermetically sealed sample containers – that are tested for E. coli colonies. E. coli is a type of bacteria that serves as an indicator of pathogens in the water.

Physical parameters we collect samples for are Total Suspended Solids (TSS) and turbidity, both variations of measurements of how much sediment is being carried downstream in our streams. Generally speaking, if TSS and turbidity concentrations are high (or increasing), one or more problems with erosion or stormwater runoff may need to be addressed.

Suspended sediment, measured as solids or turbidity, is important in streams and lakes because:

  • It limits visibility in water which can be hazardous to swimmers and boaters
  • It limits light penetration in surface waters which limits photosynthesis
  • It settles to the bottom of streams and other water bodies damaging habitat for aquatic animals and breeding areas for fish
  • Because phosphorus reacts with soil and sediment, it builds up in soils, especially where fertilizers have been applied. Runoff from the land and high stream flows causing bank erosion mobilize sediments and carry them and their associated phosphorus downstream, and eventually into Lake Champlain.

Monitoring Protocols

Addison County River Watch Collaborative’s monitoring protocols are rigorous and strictly followed. We can only expect our data to be useful if all our volunteers proceed according to our EPA-approved methods. In order for our data to be considered valid, we file a Quality Assurance Protection Plan with EPA (through the State of Vermont DEC) every year.  Our ACRWC Field Manual spells out our sampling protocols in a step-by-step manner.

During the late summer of 2017, we filmed an instructional video for samplers to refer to before and during the sampling season (April to September).


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