Watershed field trip and water quality laboratory experiments to introduce students to environmental
sustainability concepts around water sources for urban areas
Purpose: This activity has a twofold purpose that work together to introduce students to concepts in
environmental sustainability and water quality preservation approaches.
Target audience: Since this activity incorporates a field trip and subsequent laboratory investigations
into collected water samples, the activity will be spread over two to three days. The students that
participate in the activity will be walked through the field portion of the activity and the laboratory
portion of the activity in 2 hour afterschool periods.
Overview of activity: Students will first be introduced to an urban watershed to showcase different
types of water sources from urban areas. Students will collect water from the watershed in different
areas and analyze the water for biological and chemical quality. A potential site to visit is the old
Decatur Waterworks site in Mason Mill Park near Decatur, Georgia
(http://en.wikipedia.org/wiki/Decatur_Waterworks).
Figure 1. Photograph of the Decatur Waterworks from an old archive on the left and an image from
GoogleEarth on the right (http://www.medlockpark.org/2013/02/decatur-waterworks-then-andnow.html).
Starting out as a water treatment site between ~1900-1945 A.D. for Decatur Georgia, this site fell into
disrepair for many decades. This site has recently been bioremediated into an urban park that
showcases different types of water sources. Fast flowing streams of large and small sizes, retaining
ponds, and former reservoirs are present at the site and present sources of different amounts of water
quality. Students will sample the water from these different areas and investigate the water quality
using a variety of biological and chemical methods in the laboratory. The overall goal of the activity will
be to identify which place in the watershed is best for using as an urban water source. The students will
analyze the pH of the water, analyze the water for basic contaminants thereby assaying the chemistry of
the water, and observe the water samples under a light microscope to look for various biological
organisms that may be considered as contaminants from the perspective of water purification. The
students will pool their data together into a class compendium and work together to make conclusions
about the overall water quality of the area and decide which part of the watershed is the most idea
source for water for an urban area. What part of the watershed has the cleanest water from both a
chemical and biological perspective?
Protocol: Analysis of pH from water
1.
A simple assay for the pH of the water will be conducted using pH paper. The goal of this
portion of the activity will be to place pH values on a photograph of the site to give students an
idea about the overall profile of pH values on the watershed land. The students will then be
asked, “What pH is the best for treating the water from the watershed to make drinking water?”
Analyzing the water for basic contaminants and chemistry of the water
1. The students will first collect approximately 1 gallon of water from different sites in the
watershed, the same sites that pH values were collected from and allow the water to settle in a
basin for a day to analyze the overall particulate matter composition of the water and to look for
any films on the top of the water that suggest the presence of oil run off from roads or other
urban pollution sources. The overall water turbidity, particulate composition, and presence of
any visual characteristics of the water like surface films will then be placed on the same
photograph as the pH portion of the activity. The students will then be asked the question,
“What water site in the watershed has the water with the lowest turbidity, particulate
composition, and surface film presence indicating the most suitable water from the watershed
to make drinking water?”
2. Using a protocol from a DIY (do it yourself) biology laboratory book,1 students will test for the
boron concentration of the water. For this part of the experiment reagents and equipment from
a separately provided kit can be used to provide students with the necessary components to
perform this specialized assay.
Observing the water samples under a light microscope to look for various biological organisms that may
be considered contaminants from the perspective of water purification
1.
1
The students will take the water samples from the same sites in the watershed as the chemistry
and pH analyses and look at the water under a light microscope (perhaps provided by the
Clarkston High School biology department) to search for living organisms. The students will use
stains such as iodine to stain the water samples to look at the internal components of living
organisms in the water and to aid in the discrimination of organisms that can appear almost
transparent under a light microscope. The protocol for staining with iodine and additional stains
is provided by a DIY biology books2 and reagents from a separately provide kit. Additional stains
can be provided. The students will be asked the question, “What water has the least amount of
living contaminates thus making it most suitable for treatment?”
Thompson, Robert Bruce et al. All Lab, No Lecture: Illustrated Guide to Home Biology Experiments. (O’Reilly:
Beijing, China), 2012.