Stormwater 101 (Mount Gretna Edition)

What is Stormwater?

Stormwater isn’t just “rain” — it’s the water that runs off roofs, driveways, and roads during and after storms. Along the way, it can pick up debris, sediment, and pollutants such as leaves, fertilizers, pesticides, oil, and pet waste.

Why Stormwater is Different in Mount Gretna

Mount Gretna’s steep slopes send water rushing downhill quickly, while its shallow soils over fractured rock allow rapid infiltration in some places — and flooding in others. Add in our proximity to wellhead protection zones and you have a direct link between what runs off our streets and what comes out of our taps.

The Source Water Protection Plan for our region specifically flags stormwater runoff as a priority concern, because it’s one of the fastest ways pollutants can reach the aquifer.

Pollutants and Their Impact

Runoff can carry:

• • Sediment that clouds water, smothers aquatic habitat, and clogs drainage systems.

  • Excess nutrients (from fertilizers or decomposing leaves) that can trigger algae blooms in lakes and streams. The Chesapeake Bay Foundation warns that these blooms deplete oxygen, killing fish and other aquatic life.

  • Pet waste that adds bacteria and pathogens harmful to humans and wildlife.

  • Chemicals and oils from vehicles and treated surfaces.

Here in Mount Gretna, the forest, the aquifer, and stormwater are all linked. Protecting one protects them all.

From Roof to Bay

In Mount Gretna, stormwater follows a direct path: roof → gutter → driveway → street → storm drain → Conewago Creek → Susquehanna River → Chesapeake Bay. That means what happens here doesn’t just stay here — our runoff eventually impacts one of the most important estuaries in the United States.

Stormwater Policy & Oversight

Stormwater isn’t just a local challenge — it is governed through a layered system of municipal, state, and federal regulations.

• At the federal level, the U.S. Environmental Protection Agency (EPA) sets standards through the Clean Water Act and the National Pollutant Discharge Elimination System (NPDES) program.

• In Pennsylvania, the Department of Environmental Protection (DEP) requires many municipalities to hold MS4 permits (Municipal Separate Storm Sewer Systems), ensuring that stormwater is managed in ways that protect streams, aquifers, and downstream water bodies.

• Locally, the Lebanon County Conservation District (LCCD) plays a key role in reviewing development projects and ensuring compliance with erosion, sedimentation, and stormwater standards.

• Community members can also get involved through Penn State’s Master Watershed Steward Program, which trains volunteers to support conservation practices in their neighborhoods.

With climate change driving more frequent extreme rainfall events — sometimes dropping 10 to 20 inches of rain in a single storm — effective regulation and compliance are more critical than ever. When combined with local stewardship actions like rain gardens, vegetative buffers, and permeable paving, these policies form a coordinated defense to reduce flooding, protect water quality, and safeguard drinking water supplies.

Runoff in Numbers

A 1-inch rainfall on a 1,000 sq. ft. roof produces over 600 gallons of runoff. Imagine the cumulative effect across every roof, road, and parking lot in town.

What You Can Do at Home

• Install rain barrels or cisterns to capture roof runoff.

• Direct downspouts into vegetated areas instead of driveways.

• Use permeable pavers for patios and walkways.

• Plant rain gardens with native plants to slow and filter water.

• Maintain vegetative buffers along slopes and streambanks.

Why Local Action Matters in a Global Water Crisis

The urgency of water stewardship in Mount Gretna reflects challenges happening around the world. Across the American West, cities like Phoenix face limits to growth because groundwater and river supplies are increasingly strained

Globally, Iran has suffered aquifer depletion and faces growing internal and regional tensions over scarce supplies. In South Asia, India and Pakistan’s conflict over Kashmir is tied in part to control of the Indus River, which sustains millions of people. In Africa, new dams on the Nile River by upstream countries like Ethiopia pose existential concerns for downstream Egypt, where the river provides more than 90% of freshwater.

History offers sobering lessons. The decline of the Maya civilization in Mesoamerica, the Ancestral Puebloans (Anasazi) in the U.S. Southwest, and the great city of Angkor Wat in Cambodia all coincided with extended droughts and overuse of limited water. Today, climate change adds new stress: even regions not traditionally linked to drought, such as New Jersey and the Appalachians, are now experiencing more frequent wildfire risk as predicted by climate models.

These examples underscore a simple truth: when local communities conserve, enhance, and protect their water supplies, they not only secure their own future but also contribute to global stability. Stewardship here in Mount Gretna may feel small, but it is part of preventing the broader pattern of scarcity, conflict, and collapse.

Mount Gretna is small, but the same choices that prevent flooding here also safeguard one of the most important watersheds in the country. That’s real power in local hands. And it’s why every rain garden, every tree planted, and every step to reduce runoff matters — because together, they add up to clean water, resilient forests, and a healthier future for our community and beyond.