STORMWATER AND WETLAND CHEMISTRY
Lesson Plan
Tule Ponds at Tyson Lagoon

if you want to go over Tule Ponds with a booklet please download the following booklet.
pdf

OBJECTIVES:

1.  Students learn where drinkable water is from in the Fremont area.
2.  Students learn about pollutants that stormwater brings into Tule Ponds at Tyson Lagoon during a storm.
3.  Students explore ways in which stormwater is cleaned by organisms in wetlands.
4.  Students sample pond water and perform chemical tests.

VOCABULARY:

      ·        elements – a substance cannot be reduced to simpler substances by normal chemical means
·        compounds – made up of more than one element
·       heavy metals - A metal with a specific gravity greater than about 5.0, especially one that is poisonous, such as lead or mercury
·       hydrocarbons  -  organic compounds that contain only carbon and hydrogen.
·       pesticide - a chemical used to kill  insects
·     respiration - chemical energy of organic molecules is released in a series of metabolic steps involving the consumption of oxygen and the liberation of carbon dioxide and water
·        toxic – harmful and/or poisonous

BACKGROUND:

The Tule Ponds at Tyson Lagoon provides a unique opportunity to see how the needs of humans in an urban setting and other organisms can mutually co-exist.   Before humans arrived in what is now Fremont, many organisms like mammals, birds, insects, and fish inhabited the area.  As areas become urbanized (populated with people and their buildings) the natural order of things starts to change.

Prior to urbanization, water from rain soaked into the ground and slowly percolated into the layers of the soil and bedrock.   If there were more rain than the earth could handle, the water would “run off” causing floods.  These flood waters brought nutrients from the nearby hills, and the plants, especially, benefited.   As people built homes and laid down asphalt and cement for cars to use, water flowed more quickly.  They usually build homes in the flat area near a river, which is referred to as a flood plain.  The rains caused flooding and damage to many homes.  To prevent floods, engineers developed ways to allow the water to flow quickly through man-made channels that would bring water to the San Francisco Bay edge.  It works, but it also causes loss of valuable habitat for other creatures. 

The Tule Ponds at Tyson Lagoon acts as a flood area to slow down and contain water on its way out to the bay.  After water leaves the lagoon it flows through earth or concrete-lined channels out to the bay.  This area helps to prevent floods, but also acts as a natural place for organisms to thrive.  Water in this area is also from underground water that percolates up via the Hayward Fault.

These wetlands also help to remove substances that enter the system from residential, urban, and agricultural runoff.  Some of these substances are considered pollutants and may be toxic to different types of organisms. Residential and urban runoff in this area would include garbage, pesticides, oil and grease, organic matter, and heavy metals.  Agricultural runoff from nearby small farms would include pesticides and nutrients.  The frequency of these substances is intermittent and dependent on winter rains. 

During a storm event, water will run off from asphalt, cement, and saturated soil carrying with it sediments, chemicals, and trash. Ponds B and C have logs anchored at the surface to help retard the flow of objects that float, like oil and garbage. Motor oil coats fish gills, preventing

the fish’s ability to use dissolved oxygen contained in the water.  Oil can coat bird wings, making flight difficult and prevents feathers from “fluffing up” to provide insulation against the cold.     You can notice that the constrictions between the ponds help to narrow the flow and trap these lighter objects.  The removal of harmful objects protects the wildlife. 

Concentrations of sediments, chemicals, and garbage change during a storm event.  The early part of a storm transports the largest amount of larger particles whereas the later stages of storms have a higher percentage of dissolved hydrocarbons and dissolved metals.  The velocity of the water also slows as stormwater enters the Tule Pond system.  This allows heavy particles to drop out of the system first. 

Pond A is designed to slow the flow of water to allow suspended particles to drop out of the water column.  This increases the quality of the water so it is less of a potential hazard when it enters the San Francisco Bay.  The suspended particles range from heavy metals, such as copper (Cu), lead (Pb) and zinc (Zn), to simple particles like sediment and soil.   The particles increase turbidity and prevent the penetration of sunlight to phytoplankton.  Increased nutrients in the water caused by fertilizers (such as nitrogen (N), phosphorus (P), and Potassium (K) create algal “blooms.”  As the plants decompose they cause conditions unfriendly to organisms in the water (eutrophication). Lead comes from paints, wood staining products, and emissions from diesel and gasoline operated vehicles.  Zinc is from automobile tires, paints, and wood staining products.  Copper comes from plumbing, electroplating processing wasters, brake pads in automobiles, and algaecides.   In high dosages these substances can be hazardous to organisms that live or frequent the ponds

Water quality is frequently enhanced as water passes through wetland.  Plants help to slow the flow of surface run off and cause sediment to settle out.  Living aquatic plants like algae and large emergent plants like tules and cattails, add dissolved oxygen to water during photosynthesis.   Wetland plants support much of the life in open water, and plants like cattails and tules provide shelter for larger animals living in the pond.

PROCEDURE:

1.  Show students Periodic Table of the Elements placemat and review elements and compounds.  Define a heavy metal.

2.  Define a watershed by having students circle the local watersheds in the Fremont area.

3.  Discuss information in the background.  Instruct students to read the graph of “Heavy Metals from Transportation.”   Answer the questions in the booklet.

4.  Before you go on a walk have the students do the following chemical experiment.

Add 1-2 drops of bromothymol blue to 15mL of water in a 25 ml graduated cylinder. Gently blow into the tube using a straw until it changes color to yellow. Have the students discuss the change. [The change occurs because CO₂ , has been added to the solution, making it more acidic therefore causing a color change. Remember, humans produce carbon dioxide and utilize oxygen whereas plants utilize carbon dioxide and produce oxygen]

Place a piece of elodea or “green water” from Tule  in the 25mL graduated cylinder with the yellow solution and insert a cork stopper in the beak of the cylinder. Expose the cylinder to sunlight for 20 minutes. [The yellow solution will change back to blue because the plant will utilize the carbon dioxide, making the solution less acidic, converting the color back to blue. ]

5.  Go on a walk of the facility and then when you return discuss what chemical reaction has taken place. Write the following reaction on the board:

[carbon dioxide + water - yields - carbohydrate + oxygen + water]

Explain the exchange of gases and how humans and plants live together in a mutual relationship. Without plants humans would not have oxygen and without humans plants would have no carbon dioxide. Through photosynthesis, plants produce food for both themselves and other living organisms. Remind students that when animals eat plants they too are eating the food that the plants produced.

FOR MORE LESSONS:

http://msnucleus.org/membership/html/k-6/wc/water/5/wcwa5_3a.html

http://msnucleus.org/membership/html/k-6/lc/plants/5/lcp5_3a.html