Agri Kultuur August / Augustus 2018 | Page 22

ponds along the main canal. At present, there are 10 medium- and small-sized melon-like reservoirs and 2 671 weirs and ponds in the irrigation district. The reservoirs are connected to the Changqu (Bai Qi) Canal with ditches and canals and are controlled by water gates. The Dujiangyan irrigation system, located in southwest China’s Sichuan Province, and was constructed around 256 BC which produced comprehensive benefits in flood control, irrigation, water transport and general water consumption. It consists of headwork, water diverting channels at various levels in irrigation district, ponds, weirs and farmlands. The headwork system mainly consists of the three major parts of Fish-Mouth Diverting Levee, Flying-Sand Weir (spillway) and Bottle Neck Canal and the auxiliary projects of the Baizhang Dike and the Renzi Dike. Starting from the point of the Fish Mouth Levee, the water flow is controlled by water diversion levees and overflow weirs made of bamboo cages and timber piles. In the irrigation district, there are now 111 main canals and sub-main canals that run 3 664 km long, 260 branch canals that run 3 234 km long, each irrigating thousands of hectares of farmland, and field ditches below branch canals that run over 34 000 km. It now irrigates around 668 700 hectares of farmland. The Jiangxiyan Canal in eastern Zhejiang Province, consisting of Jiang and Xi dams and was built in the 14th century and is still in use. The Jiangxiyan Irrigation System is composed of water-diversion headwork, irrigation and drainage canal network and control work. The water-diversion headwork includes Jiang Weir (upper weir), Xi Wei (lower weir), intake AgriKultuur |AgriCulture gate and scouring sluice. Jiang Weir is 100 m long; its bed is 32 m wide and 63.2 m high and located on the right side of the sandbank on the upper reaches of the Lingshangang River. Xi Weir is 50 m long and its bed is 30 m wide and 63.1 m high and located on the left side of the end of the sandbank on the lower reaches. Xi Weir is arc-shaped, diverting water into the main irrigation canal through the intake gate. The total irrigated area is 2 333 ha Built in 214 BC, the Lingqu Canal covers 4 333 hectares of farmland and is a major irrigation structure in southern Guangxi Zhuang Autonomous Region, connecting the basins of the Yangtze River and Pearl River. The irrigation system includes headworks, main canal project, flood control project, gravity and water lifting irrigation systems among others. The headworks are located on the Xiang River. It consists of the Plow Beak, the large and small-scale weirs, as well as the south gate and the north gate. India’s two historical irrigation and drainage systems are- Large Tank (Pedda Cheru) and the Sadarmatt Anicut system. Large Tank (Pedda Cheru) was restored in 1897 and has 3 sluices with one located at the weir. The weir is located on the left flank with a height of 3.75 m and the length of the weir is 145 m. The maximum flood discharge is 8 860 cusecs. The length of the bund is 1 800 m and the maximum height of the bund is 14 m. The capacity of the tank is 4.86 Mm 3 and the water spread area of the tank is 3.05 km 2 . The Sadarmatt Anicut was built in 1891 across the river Godavari on the left arm in 22