Niagara's Plumbing: Lake Erie Drains to Lake Ontario

Niagara Falls isn't a source—it's a drain. The Niagara River connects two Great Lakes, moving 5,700 m³/s (200,000 cfs) over the escarpment.

The Connection

• Upstream: Lake Erie (174m / 571 ft elevation)
• River: 58 km (36 mi) north, dropping 99m (325 ft) total
• Falls: 51m (167 ft) vertical drop (Horseshoe + American + Bridal Veil)
• Downstream: Lake Ontario (75m / 246 ft elevation)

Flow Control

Natural flow would erode falls upstream ~1m/yr. Since 1950s: International Joint Commission mandates minimum flow over falls (tourism) + maximum diversion (hydropower). Sir Adam Beck (Canada) and Robert Moses (US) plants take 50–75% of flow. Night/off-season: more diverted.

Geologic Context

Niagara Escarpment: cuesta (tilted resistant caprock over soft shale). Falls retreat 11 km in 12,500 years. Current rate: ~0.3 m/yr (engineered). In ~50,000 years, falls reach Lake Erie — becomes rapids.

Beyond the Falls

Lake Ontario → St. Lawrence River → Gulf of St. Lawrence → Atlantic. The Great Lakes' only ocean outlet. Every drop from Superior, Michigan, Huron, Erie passes here.

Two lakes. One river. A waterfall that moves mountains — slowly.