In this work we compare three megadeltas that share dry climates but differ in how they interact with the coast. Each is shaped by a dominant force: waves in the Nile, tides in the Indus, and river flow in the Yellow River Delta. Over the past 50 years, these deltas have faced major changes due to both human actions and natural events. Using shoreline trend analysis, we trace how land is gained or lost in each region. Some changes are easy to see, while others follow hidden patterns linked to delayed or overlapping impacts. Our findings help reveal how delta shorelines respond over time and why long-term tracking is essential for understanding future risks.