Stormwater 101: From Rain to Runoff

I still remember the moment stormwater became real to me.

It was a heavy rain day during lunch. We were in our classroom, and one of my friends pointed out the window at the parking lot. Water was rushing down the pavement in rivers, carrying leaves, dirt, bits of trash—all flowing toward a storm drain. I suddenly realized I’d never actually thought about where that water went. I just knew it disappeared.

That question—“where does it go?”—became the foundation for one of our most popular Earth & Us workshops.

The Journey of a Raindrop

Let me trace it for you, because it’s not as simple as you might think.

When it rains on a school parking lot, the water doesn’t soak into the ground like it would in a forest. Instead, it flows across the asphalt, picking up things as it goes: oil residue from cars, dirt, small pieces of plastic, fertilizer from landscaping. This mix—stormwater plus pollutants—rushes into a storm drain.

Here’s the critical part that most people don’t know: storm drains do not go to water treatment plants. They connect directly to local waterways—creeks, rivers, and wetlands.

So that contaminated water flows straight into our local waterways without any treatment.

What’s in Stormwater? The Inventory

During one of our workshops, I brought in water samples from a storm drain in Frisco and a stream downstream. We looked at them under a microscope. The kids were shocked at what they saw—particles, bacteria, algae blooms. It made the abstract concept of “pollutants” concrete.

Here’s what typically ends up in stormwater:

From vehicles:

• Oil and grease
• Heavy metals from brake wear (zinc, copper, cadmium)
• Tire particles
• Antifreeze

From landscapes:

• Fertilizers (nitrogen and phosphorus)
• Pesticides
• Soil sediment

From human activity:

• Trash and microplastics
• Pet waste
• Food waste
• Cleaning products

During construction:

• Dust and sediment
• Concrete slurry
• Debris

In a single heavy rain, a medium-sized parking lot can discharge pollutants equivalent to a small oil spill. That’s not exaggeration—that’s what water quality studies show.

The Impact on Water Systems

I visited a local creek near one of our partner schools. It was spring, and after a heavy rain, the creek was brown and cloudy. The normal clarity was gone. Here’s what happens:

Immediate impacts:

• Sediment clouds the water, blocking sunlight from reaching aquatic plants
• Sudden increases in nutrient levels (nitrogen, phosphorus) cause algae blooms
• Algae blooms deplete oxygen, creating “dead zones” where fish can’t survive
• Oil and chemicals are toxic to aquatic life

Long-term impacts:

• Heavy metals accumulate in fish tissue
• Fish populations decline
• Ecosystems become imbalanced
• Water quality deteriorates, affecting human water supplies

I showed these photos and explanations to students, and one girl asked: “But can’t we just clean it up?” The answer is yes, but it’s much easier to prevent pollution than to clean it up after.

Understanding the System: How Stormwater Moves

During our most popular workshop, we create a stormwater model. Here’s what we do:

We take a tilted piece of plywood and create a miniature city—parking lot, street, roof surfaces. We mark out where a storm drain would be. Then we put water mixed with food coloring, dirt, and small debris at the top and let it flow downhill.

What students observe:

1. The water flows extremely fast—much faster than rain naturally falls
2. Everything in its path gets swept along
3. The water travels directly to the drain without any filtering
4. The pollutants reach the waterway immediately, undiluted

This simple model teaches more than any lecture could. Students see that rain on a parking lot is fundamentally different from rain in a forest. In the forest, water slowly percolates through soil, getting naturally filtered. In a city, it’s a highway for pollution.

Real-World Solutions: What’s Being Done

After understanding the problem, students always ask: “So what do we do about it?”

Several solutions exist, and some are being implemented in Frisco:

Green Infrastructure

Rain gardens and bioswales are landscaped areas designed to capture and filter stormwater. I visited one school that installed a rain garden after watching our workshop. It’s a shallow basin with native plants. When it rains, water collects there instead of flowing into a storm drain. The plants and soil act as a filter, removing pollutants naturally.

Student impact: Students designed the rain garden, selected plants, and now monitor it. They’ve documented three species of frogs, various insects, and improved water quality in a nearby stream.

Permeable Surfaces

Some parking lots and walkways are being replaced with permeable pavement that lets water through. Instead of flooding the surface, water soaks through and is filtered by layers of gravel and sand below.

Stream Restoration

Several creeks in Frisco are being restored with riparian buffers—strips of vegetation along the banks that filter stormwater and provide habitat. Students have participated in planting native trees and shrubs.

Rain Barrels and Cisterns

Individual schools are installing systems to capture roof runoff for irrigation. This reduces the volume of stormwater that enters the system while providing a free water source.

What Students Can Do

The most powerful moment in our workshops is when students realize: I can do something about this.

Here are actions that are actually happening:

1. Storm Drain Stenciling

One Earth & Us team organized a project where students stenciled “Don’t Dump - Drains to Creek” on storm drains. It sounds simple, but research shows that people dump fewer things when they see this message. The visual reminder changes behavior.

2. Pollution Prevention

Students organized parking lot cleanups at schools. Before rain events, they collected trash and debris that would otherwise end up in storm drains. One team documented that they removed 45 pounds of debris in a single cleanup—material that would have become water pollution.

3. Advocacy for Green Infrastructure

Student groups presented to school boards about installing green infrastructure. One school is now planning a rain garden for next year, directly because students advocated for it.

4. Water Quality Monitoring

With proper training, students can collect water samples and monitor water quality in local creeks. Several students in our workshops have started ongoing monitoring programs—tracking seasonal changes and the impact of rain events.

The Bigger Picture: Thinking Like a Watershed

Understanding stormwater taught me to think differently about cities. I realized that every raindrop on every surface is part of a system. Every choice about what surface we create—concrete or permeable, vegetated or bare—affects that system.

When I visit schools now, I look at the landscape differently. I see an impervious surface and think, “That’s water pollution waiting to happen.” I see a rain garden and think, “That’s a student learning about systems.”

Why This Matters for Environmental Leadership

Here’s what I tell students: “Understanding stormwater is understanding how cities work. It’s understanding that our choices—what surfaces we build, what chemicals we use, how we maintain our landscapes—flow directly into nature. And when we realize that, we start thinking about solutions.”

That systems thinking is what environmental leadership means. Not just caring about the environment in abstract terms, but understanding the concrete connections between human infrastructure and natural systems.

Getting Involved

If you want to explore stormwater issues in your community:

1. Map your watershed - Find out where your storm drains go
2. Monitor water quality - Partner with a local environmental organization
3. Propose green infrastructure - Talk to your school or city about rain gardens or permeable surfaces
4. Change behavior - Start a campaign about what shouldn’t go down storm drains
5. Join Earth & Us - We offer stormwater workshops and monitoring training

The next time it rains, pay attention. Watch where the water goes. Think about what’s in it. And imagine what could be different if we designed our cities with water quality in mind.

That’s the beginning of environmental leadership.