In 1987, in order to develop new land by the seaside, the Tainan County government built a horseshoe-shaped dike at the mouth of the river. This created an area of more than 600 hectares which, while at this point still inundated at high tide, comes above water level at low tide.
民國七十六年，台南縣政府為開發海埔新生地，在曾文溪河口圍起馬蹄形的堤防，形成一片漲潮時淹沒、退潮時露出水面六百多公頃的沙洲。