Which outcome occurs when sediment supply decreases significantly in a coastal area with a longshore current?

💡 Explanation

Decreased sediment weakens deposition, triggering barrier island landward migration with rising sea levels by the mechanism of overwash. This occurs because erosion overtakes sediment build-up; therefore, islands retreat rather than accrete seaward.

• Which mechanism causes relatively shallow sill depths at the mouth of many fjords?
• Which mechanism causes the formation of terraced alluvial fans in arid environments after prolonged tectonic uplift?
• Which global precipitation effect is caused by the intertropical convergence zone (ITCZ)?
• Which outcome is more likely when floodplain levees subside unevenly?
• Which outcome occurs when a substantial section of a naturally formed levee is removed along a major river?
• Which increased hazard arises when pyroclastic surge encounters seawater?