Why has Dongting Lake become smaller over time?

Dongting Lake has decreased in size primarily due to the reclamation of land along its banks and within its surrounding dikes, a process that was particularly active between the 1930s and the 1950s.1

This reduction in area was further accelerated by the gradual silting up of the lake, caused by the significant volume of sediment deposited by the rivers that flow into it, most notably the Yangtze River. By the 1970s, these combined factors resulted in the lake's surface area being approximately 400 square miles (1,000 square km) smaller than it had been in 1937.1

While this reclamation once hindered the lake's ability to act as a vital flood-retention reservoir, the government has since prohibited such practices and initiated various conservation and restoration projects to reconnect the lake system and reinforce its banks.1