Velocity and volume of stormwater in heavy rain events can negatively impact our waterways.  Large amounts of water running quickly can erode the streambank, increase sediment and convey stormwater pollution downstream, All this can alter the characteristics of a naturally healthy streams and impact water quality in our source water in negative ways over time.

As part of the overall management of the urban watershed, PWD’s stream restoration initiatives helps stabilize and manage the stream flow to minimize erosion and restore natural habitats upstream and downstream.

Planting trees and other vegetation along the stream bank and reintroducing rock riprap for example are some of the restoration actions that help improve the health of the tributaries to make healthy waterways overall.

Past development practices have altered natural stream patterns and degraded riparian ecosystems. PWD and many others are now adopting the practice of   “working with nature” . These ecological restoration projects bring back ecosystem functions and protect critical water and sewer infrastructure along the stream corridors.

Ecological restoration means promotes stable waterways, asset protection, resilient riparian habitat and healthy streams.

Waterways in urban areas impacted by development, especially from the paving of large swaths of land, benefit from best management practices such as the planting trees and other vegetation and the restoration of streams’ natural features. This promotes a more natural flow in the watershed and helps restore the ecosystem.

Students will view videos of heavy rain storms with water rushing into the storm drain,

Using the images of exposed roots on this webpage from WHYY    https://whyy.org/articles/wissahickon-valley-park-creek-protection/

Ask students what they see in the picture. What is happening…looking for exposed roots of trees etc

Slide 2: What causes erosion? (tapping prior knowledge)

Why is erosion a problem?   Looking for water quality issues, flooding, etc…

Write a reflection or facilitate a brief discussion addressing the following prompts:

Slide 3: Should we restore streams? Why or why not? How does this address the idea of the entire watershed upstream as well as downstream?

Let’s explore –

In a previous Learning Experience your students created a “live” model of a stream when they acted out stormwater runoff , pollution and the benefits of riparian buffers. In their living model students acted like a buffer along their stream bank and captured objects to prevent them from getting into the stream  (the aisle) or at least slowing them down.

We are going to recreate that model but the focus this time will be on erosion and deposition.  Due to changes to the natural buffers along the rivers and streams, increased stormwater runoff, and the impact of trash and pollution stream banks suffer erosion or silt build up.

This activity will set up the exploration for the PWD’s stream restoration projects that help to restore the stream bank and the balance of natural ecosystems.

Step 1: Make the stream path

Arrange the classroom so that there is a cleared center aisle down the middle. This will represent your waterway. Make sure there is enough room on either side of the aisle (now your flowing waterway)  for two groups of students to become the stream bank on either side of the aisle.

Step 2:  Make a stream bank

Select some of the students to line up facing each other on either side of the aisle (now your flowing waterway) . They can stand side by side or link arms. These students are your stream bank. These students should have pieces of crumpled up paper and other objects that will represent sediment that will be deposited into the river as the water moves.

Step 3:  Activate your model!

It is important for you to choreograph this simulation, narrating what is happening as the students bring the model to life.

The students playing the role of water will move down the stream. Since the stream is straight, water moving down the stream will move quickly, given there are no turns or barriers to slow it down. As the water moves quickly sediment will be picked up and join the flow of water. Students can hold pieces of sediment and carry it with them to the end of the stream.

Rerun the simulation but this time have the students create a bend or two in the river. This has the effect of slowing down the flow of water. Sediment is more likely to be dropped or deposited in these areas.

If a student in the stream bank “runs out of” sediment, you might signal that the student enters the flow of water and deposits themselves at a curve in the stream. This would represent a major erosion event in the stream bank.

You can also add other elements to your stream. Add a chair or boxes to force the water to slow or fork. Sediment would build up at this location as well.

Introduce vocabulary as they identify and describe the different restoration tools.

Ask students:

• Where did erosion happen?
• Where was sediment transported?
• Where did deposition happen? Why?

Has erosion or deposition changed the stream?

Show students an example of two stream restoration projects in Philadelphia.

What do they notice, what do they wonder?

Great pictures from Cobbs Creek  https://water.phila.gov/projects/p50223/

Great pictures from Pennypack  https://water.phila.gov/projects/p50227/

(needs narrative once we know this is the right sequence of activities?)

Use the eco restoration graphic to show students what a natural stream channel looks like. Highlight the different areas around the stream and have students think about the services each area or natural tool provides to protect the stream.

Reinforce vocabulary as they identify and describe the different restoration tools.

Assign one of the types of restoration tools to groups of students. Have them read about their tool and then explain to the class how the tool provides important services in protecting the stream.

The WHY! This is a great description of the different ways PWD is trying to restore streams:

https://water.phila.gov/sustainability/ecorestoration/tools/

What makes a stream healthy? – Use the resources linked below to view the healthy macroinvertebrates, and other bio indicators that tell us the stream is healthy. These include  mayflies, caddisflies, and stoneflies. If you are able to collect a sample of stream or creek water these are easily collected and examined back in the classroom using microscopes or even close observation.

Mayflies:  https://stroudcenter.org/mayflies/

Streamside Forests: https://stroudcenter.org/wp-content/uploads/Streamside-Buffers-Brochure_2022UpdateWeb.pdf

FOW What is in my stream?  https://fow.org/creek-macroinvertebrates/