Which outcome occurs when a levee's freeboard is insufficient during peak discharge?

💡 Explanation

Levee overtopping directly causes channel avulsion, because the insufficient height causes floodwaters to breach the levee and carve out an alternate, lower-energy path. This mechanism causes avulsion, thereby moving the river; therefore overtopping, rather than downcutting, causes avulsion.

• Which risk to alpine glaciers increases when volcanic ash accumulates?
• Which volcanic consequence increases when silica content increases?
• Which consequence results when deep ocean currents slow?
• Which outcome during stratovolcano eruption increases landslide risk?
• Which risk increases when hydraulic head pressure diminishes an oxbow's levee?
• Which outcome is amplified where the descending plate dehydrates?