How is the Yi River formed?

You should tell Yichuan if you win the tour.

Soft wind and peach blossom waves,

The heating is frivolous and the sun is shining.

People are generally concerned about tap water,

All your heart is in front of Bibo.

Looking back,

Talking about rejuvenation.

This is the Seven Laws written by Wu Wen, a poet in Ming Dynasty, when he traveled to yi river. Yi River, also known as Yishui, has three sources, four sources and five sources at its headwaters. 1988 10, Huaihe River Regulation Committee of the Ministry of Water Resources, Yishu River Management Office of Yishu Si Bureau of the Ministry of Water Resources, Linyi Water Conservancy Bureau of Shandong Province, Yiyuan Water Conservancy Bureau and other relevant departments conducted on-the-spot investigations. The conclusion is that the Yi River has four sources, and the main source is Xujiazhuang River (the largest basin area and water quantity). The four sources are: 1, Xujiazhuang River, which originates in the southwest of Longziyu Village, Xujiazhuang Township at the northern foot of Xiaoheishan;

2. Dazhangzhuang River, originating from the northern foot of the old Songshan Mountain in Zhangzhuang Village;

3. Nanyan River (also known as Renlizhuang River) originated in Nanshan, the valley next to Zhangjia in Zhangzhuang Village;

4. Gaocun River (also known as Tianzhuang River) originated at the northern foot of Langwo Mountain in Zhangzhuang Village. Tianzhuang Reservoir, where the four sources meet, is the "merger through Longdong Mountain" in the Qing Draft. The reservoir, hereinafter referred to as yi river, flows through Yiyuan, Yishui, Yinan, Hedong, Lanshan, Luo Zhuang, Cangshan and Tancheng County, and enters Jiangsu Province from Wujiadaokou Village in Tancheng County to Roman Lake in xinyi city, Jiangsu Province. The total length is 574 kilometers, and the drainage area is 17325 square kilometers. The main tributaries are Wenhe, Weihe, Weihe, Bengbu and Suhe. The annual runoff is 35 1 100 million cubic meters, and the widest part of the river bed is 1.540 meters.

Yi River was once an important tributary of Huaihe River. Since the Yellow River seized the Huaihe River and the Huaihe River was silted up, the Yi River has lost its access to the sea. After the founding of the People's Republic of China, this state was changed after the completion of artificial rivers such as Xinyi River and Xinshu River. Xinyi River has become the main channel to the sea of Yihe River.

Yi river is the mother river of Linyi, which runs through the southern plain of Linyi from Yimeng Mountain area. Surrounded by mountains, the river flows slowly south. On both sides of the river, the grass is delicious and the trees are lush, showing beautiful scenery of clear water and green mountains, white clouds in the sky, lush forest fruits and fragrant rice flowers. In old China, the water was deep and fast. Sailing boats could reach Nanma in Yiyuan, but it often brought disasters to people. There is a ballad, "Talk at the mouth of a river, the water overflows country-specific ones, the forest is flooded, and Pizhou is brought to the south". After the founding of New China, the Party and the people's government attached great importance to the management of the Yi River, and built more than a dozen large and medium-sized reservoirs in the upper reaches of its main tributaries, such as Bashan, Dike, tangcun and Xujiaya. And reinforce dikes downstream and build flood diversion gates, which not only basically controlled floods, but also benefited from fish farming, power generation and irrigation. 1997, the world's longest Xiaobudong rubber barrage was built in the east of Linyi, forming a water surface of 12000 mu, making the Yi River more charming.

The geographical coordinates of the basin are 1 17 25' east longitude to 1 18 42' north latitude to 34 23' north latitude, Yiyuan, Yishui, Yinan, Linyi, Mengyin, Pingyi, Feixian and Tancheng.

The most upstream of the basin is divided by Lushan anticline and Weihe River, and the rest of the veins of Yi Shan anticline are divided by Shuhe River in the east. The terrain is high in the northwest and inclined to the southeast. From Heyuan to Dong Wen Estuary, most of them are mountainous areas with overlapping mountains, with an altitude of 300-800 meters. Most of them are low hills and highlands in Xiewu, Qingtuo, Chashan and other places, with the ground elevation of 200-400 meters. The slope of the plain is 1/3000 ~ 1/2000.

Geomorphologically, the Yihe River Basin belongs to the tectonic denudation and accumulation plain area. The geotectonics belong to a part of the uplift of Luxi fault block. The yi river River Basin is bounded by the overlap of the Yi-Shu fault zone (including Yishui-Tangtou fault zone and Tanzi-Gegou fault zone), and the west of the boundary includes Yiyuan, Yishui, most of Yinan, Mengyin, Pingyi, Feixian, Linyi, Cangshan and Tancheng. The ground uplift is dominated by fault blocks, which are NW-trending and banded, and Mengyin and Pingyi are relatively depressed, forming a fault basin. There are Mesozoic volcanic eruptions and continental clastic rock deposits in the fault basin. Cenozoic tertiary fault activity is particularly strong, forming Yishan, Mengshan and other mountainous areas, laying the present mountain landform in Yimeng Mountain area.

The lithology of the basin is complex, including Neogene purplish red sandstone, glutenite, Mesozoic Cretaceous volcanic rock series, fluvial and lacustrine sand shale and Jurassic sand shale, Paleozoic Carboniferous and Permian coal measures strata, Ordovician and Cambrian limestone, Archaean complex and igneous rocks in various stages. Limestone has the largest distribution area and is rich in karst water.

During the Ming and Qing Dynasties (1368 ~1911), two water intakes, Jiangfengkou and Lukouba, were set up on both sides of the Nanyi River in Linyi County to divert water, so as to facilitate the navigation of the China Canal. Before 1949, due to the out-of-control floods in hilly areas, the downstream areas were invaded by the Yellow River to seize the sediment and waste of Huaihe River, which became the flood corridor in the lower reaches of Si, Yi and Shu, and the floods and droughts in yi river were serious. Since 1949, Shandong and Jiangsu provinces have successively built dredging projects, and opened the Xinshu River, Xinyi River, Fenyi Waterway and Picang Diversion Canal to solve the flood discharge in the middle and lower reaches. Preliminary improvement of the lower reaches of Laoyi River and related drainage channels; Soil and water conservation has been carried out in the upper reaches, and hundreds of large, medium and small reservoirs, such as grange, Bashan, levee, Tangcun, Xujiaya and Changli, have been built successively to retain floods and develop irrigation and aquaculture. It starts from Pengdaokou on the east bank of South yi river in Linyi County in the east and reaches Daguanzhuang in Linshu County on the west bank of Shuhe River in the east, with a length of 20.2 kilometers and a bottom width of 200 ~ 265,438+00 meters. The designed and checked flood flows are 4000m3/s and 5000m3/s respectively, which enter the Yellow Sea through Xinshu River in Hongkou, Jiangsu Province. The Picang River diverts the flood from Jiangfengkou on the west bank of yi river to Tanshang Village in Pixian County, Jiangsu Province on the east bank of the Central Canal, with a designed flood discharge of 3,000 cubic meters per second, which flows into Xinyi River through the Central Canal and Lake Rome. Through preliminary control, more than 660,000 hectares of cultivated land have been reduced due to floods and droughts on both sides of the strait, and commodity grain bases have been built in some areas.