Why did the French originally plan a sea-level canal through Panama?

The French decision to pursue a sea-level canal across the Isthmus of Panama was primarily driven by the influence and recent success of Ferdinand de Lesseps. Having successfully led the construction of the Suez Canal, Lesseps utilized his reputation to garner public support and capital for a similar sea-level design in Panama.1

Lesseps’s approach was flawed because he either lacked familiarity with the unique conditions of the Panamanian isthmus or failed to acknowledge how they differed from the arid environment of Suez. Unlike the flat, sandy terrain of the Suez, Panama presented a challenging tropical landscape characterized by dense jungles, heavy rainfall, and mountainous terrain, including the Continental Divide. Although engineers like Adolphe Godin de Lépinay proposed a more practical high-level lock-type canal, their warnings were ignored in favor of the sea-level plan. The project ultimately collapsed due to the insurmountable environmental challenges, lack of a sound engineering plan, and the devastating impact of tropical diseases on the workforce.1