Friday, February 21, 2020

Monitoring Streams With Visual Assessment Important For Assessing Stream Conditions

By Danielle Rhea, Penn State Extension Educator

Monitoring our waterways is important for assessing stream conditions and water quality and using visual assessments is a low-tech way to evaluate stream health.
Oftentimes we look at a stream and make a quick assumption of its condition. 
A stream with a cobble bottom that is well connected to its floodplain with an abundance of streamside trees is typically thought of as healthier than a stream with a muddy bottom and steep vertical banks that lacks riparian vegetation. 
The more habitat we see, the more fish we expect to find. Streams and rivers are a complex interaction between biological, physical, and chemical processes. 
Changing the physical features of a stream, such as removing riparian vegetation, can result in chemical changes, such as warmer water and increased nutrient and sediment loading, that will ultimately affect what can live in the stream. 
While not always the case, many studies have shown a positive correlation between physical habitat and the present aquatic community. 
By completing a visual assessment of a stream’s physical properties, we are able draw conclusions of the overall stream health.
Visual assessments evaluate multiple physical parameters and convert qualitative information to quantitative scores. 
By scoring a stream, it becomes easier to determine a baseline level of stream health, justify the need for a restoration project, or compare how a stream’s condition changes over time. 
While assessing the biological, physical, and chemical properties of a stream is the best way to get a full picture of stream health, it can be expensive and require specialized training and equipment, making it a difficult feat for watershed associations and other community or volunteer based groups. 
Performing visual assessments is a valid way of obtaining basic stream health evaluations that can be successfully done with a little training, time, and enthusiasm.
Many different protocols have been created for performing stream visual assessments. 
One example is the Stream Visual Assessment Protocol (SVAP) that was developed by the U.S. Department of Agriculture Natural Resources Conservation Service to be a simple, user-friendly assessment tool for riparian landowners. 
The SVAP starts with a site diagram and assesses 10-15 parameters including channel condition, hydrologic alteration, width of the riparian zone, bank stability, water appearance, nutrient enrichment, barriers to fish movement, instream fish cover, presence of pools, and macroinvertebrate habitat. 
Each parameter is scored from 0-10 to rank a stream from poor to excellent condition.
Another well-known visual assessment protocol is the habitat assessment portion of the U.S. Environmental Protection Agency’s Rapid Bioassessment Protocols For Use in Streams and Wadeable Rivers
This protocol assesses ten parameters including available cover, pool substrate, pool variability, sediment deposition, channel flow status, channel alteration, channel sinuosity, bank stability, vegetative protection and riparian zone width and scores them from 0-20. The higher the score, the better the condition. 
Additional water quality parameters such as temperature, dissolved oxygen, pH and the presence of large woody debris can also be recorded on the data sheets; however, without this information, a total score can still be obtained.
Finally, Penn State Extension and the Penn State Agriculture and Environment Center developed the First Investigation of Stream Health (FISH) Protocol as a citizen science monitoring protocol. 
This protocol not only assesses habitat, but also provides the opportunity to record information on the organisms living in and around the stream to get a fuller picture of stream health.
One of the main benefits of performing visual assessments is that by scoring a stream numerically, it is easy to compare it to other similarly evaluated streams or to gauge changes over time. 
In this manner, restoration projects can be prioritized and improvement or degradation over time can be illustrated in a measurable way. 
Consequently, regardless of the protocol chosen to complete a visual assessment, consistency in both the method and how each parameter is assessed is key for obtaining results that can be compared from stream to stream and from year to year.

(Reprinted from Penn State Extension Watershed Winds newsletter.  Click Here to sign up for your own copy.)

[Posted: February 21, 2020]  PA Environment Digest

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