P'O-YANG, LAKE

Chinese (Wade-Giles) P'o-yang Hu, or (Pinyin) Poyang Hu, large lake in northern Kiangsi sheng (province), China. It lies in a depression south of the Yangtze River and is fed by various rivers from Kiangsi, the most important being the Kan River, which drains almost the whole of Kiangsi. P'o-yang Lake itself drains into the Yangtze at Hu-k'ou. The lake's size is ill defined, a whole system of lakes and marshes being subject to very great seasonal variation. At its greatest extent it is about 95 miles (150 km) in length from north to south and has a breadth of 19 miles (31 km) from east to west. In winter the whole area becomes a huge marsh, intersected by waterways and dotted with hills surmounted by villages. In summer the whole area is flooded, and the hills become islands. The water level depends on complex factors, including the level of the Yangtze River as well as the level of its tributaries. The P'o-yang has always been an important retention lake that receives some of the excess of the Yangtze in flood time; consequently, the surrounding farmland is often extensively flooded. The lake has been silting up in recent centuries. Even in summer there is a wide margin of reedbeds and swamp around the lake itself, and over the centuries large areas of farmland have been reclaimed from the lacustrine deposits. Nan-ch'ang, capital of Kiangsi, was once on the lakeshore but is now some 15 miles (24 km) from it. The lake is divided into two sections by a narrow neck of land called Ying-tzu-k'ou. The northern section is sometimes known as Lake Lo-hsing. The much larger southern section is sometimes known as Lake Tzu-t'ing, or Lake Kung-t'ing. The total area of the lake is about 1,383 square miles (3,583 square km), but precise measurement is impossible because the difference between flood level and low-water level is sometimes as much as 25 feet (8 m). Unlike Lake Tung-t'ing in Hunan province, Lake P'o-yang has no artificial retention basin to increase its capacity to receive the Yangtze's floodwaters.