The western seacoast was originally rising land, but because each of the two tributaries to the upstream portion of the Tsengwen River had dams built on them, plus a great amount of illegal pisciculture on the western seacoast, today reclaimed land on the seacoast is declining, not increasing.
西海岸原本是上升地形，卻由於曾文溪上游的兩條支流，各有一水庫攔截了沖刷而下的泥砂，加上西海岸大量非法濫墾魚塭，如今海岸新生地不增反減，要為鳥兒另覓一片相似的沙洲並不容易。