The biological observation of the stream, pond, or salt water is probably the most rewarding to a non-scientist.  It involves learning the vegetation and organisms that live along the creek.  It is a life-long skill to observe and appreciate what nature brings to our doorstep.  Understanding the biological component helps to determine if restoration was successful or not. 

Understanding the biology of an area takes careful inventory and observation for many years.  Seasons and weather is an important component on what life can be found in an area.  Even places that are just a few kilometers apart may be very different. 

Biological assessment of an area is a long and tedious process.  A base survey just reflects the diversity, not abundance or specific location within the area under investigation.  If a stream corridor has an abundance of larger animals, that infers an ecosystem which is supporting itself.  The food web has an internal structure that supports the different layers of the food pyramid. 

A complete survey of an area should include groups like land arthropods, annelids, and other small land invertebrates. Plants should include aquatic plants, trees, shrubs, other flower plants, and grasses.  Vertebrates should include birds, mammals, amphibians, and reptiles.  Birds usually dominate because in many wetlands they reflect the top of the food chain.  The more birds documented the richer the food web supporting those animals. 

Aquatic microorganisms are emphasized because they reflect most accurately the health of the water in which it lives.  It can provide clues on the chemical balance of the creek.