Chapter 11 Section 4 Water Control and Water Conservancy Projects

Everyone is very familiar with the widely circulated story of Dayu's flood control.According to ancient records, the result of Dayu's flood control not only eliminated water damage and enabled the ancestors to move from hills to plains to settle down, but also irrigated farmland, developed agricultural production, and turned water damage into water conservancy.It reflects that the issue of water conservancy has always been an issue that our ancestors attached great importance to. During the Spring and Autumn Period and the Warring States Period, along with the application of iron tools and the development of agricultural production, water conservancy construction also entered a new period.During this period, many large and medium-sized water conservancy projects were built. The famous ones are: Shaopi built by Chu State in Shouxian County, Anhui Province at the end of the 6th century BC, with a circumference of 120 miles and irrigating tens of thousands of hectares of farmland; The Twelve Canals of Zhangshui under the presidency of Zhangxian County improved the large saline-alkali land on both sides of the strait, and left a moving story of Ximenbao exposing the scam of "He Bo marrying a wife" by evil officials and witches; in 246 BC, Qin State was in Shaanxi The Zhengguo Canal built in Jingyang County turned the barren Weibei Plain into a fertile field; and the world-famous Dujiangyan.

Dujiangyan is located in Guanxian County, Sichuan Province. It was built by Li Bing and his son, Shu Shou of Qin State, around 256 BC. It is still completely preserved and playing a role.It consists of three parts: Fenshui Yuzui, Baopingkou and Feishayan.The three parts are both independent and interdependent, forming an organic whole. Fenshui Yuzui, also known as Dujiangzui, is located on the central line of the Minjiang River.Its shape is like a fish mouth facing the upper reaches of the Minjiang River, dividing the Minjiang River into inner and outer rivers.The Waijiang River is the mainstream of the Minjiang River.Water from the Neijiang River enters Baopingkou through the embankment and flows to the Chengdu Plain, where it plays three major roles: shipping, irrigation and flood diversion.Both the fish mouth and the embankment are made of local materials, made of large bamboo cages filled with pebbles.

The treasure bottle mouth is named for its shape like a bottle mouth. It was built by splitting the stone Yulei Mountain into two halves by manpower.The steep and isolated rock on the south bank is called Lidui, which was split from Yulei Mountain.Baopingkou is the throat that controls the flow of the Neijiang River, and it plays a role in ensuring that enough water passes through here and flows into the densely covered farmland irrigation canals in the Chengdu Plain. Feisha Weir is a low weir built with bamboo cages and stones, and it is a gate and dam project for flood diversion and siltation reduction in the Inner River.When the flood hits, excess water from the Neijiang River will overflow from the top of the weir into the Outer River; if the flood is too large, the weir will be washed away and the flood will flow directly into the Outer River, thus ensuring the safety of the Neijiang irrigation area.At the same time, it plays the role of reducing silt and discharging sand.Due to the blocked water at Baopingkou, the flow rate slows down, and the sediment brought from the upstream will be deposited here.However, a section of the inner river in front of Feishayan is a bend, which produces a bend circulation. Feishayan is located on the convex bank of the bend, which can make the bottom flow carrying sediment discharge to the outside of the weir, reducing the siltation in front of Baopingkou and The sediment content in the water flowing into the mouth of the treasure bottle.

There are also three stone figures carved in Neijiang Estuary, standing in the water and functioning as water gauges.It is used to measure the inflow flow of the Neijiang River, and provide a basis for adjusting the water level of the entire engineering system, so as to achieve the purpose of rationally distributing the flow of flood and low water. The completion of Dujiangyan has irrigated 3 million mu of fertile land in the Chengdu Plain, turning it into a high-yield field that guarantees harvests during drought and flood.In order to commemorate the achievements of Li Bing and his son, later generations built a Erwang Temple on the east side of Yuzui in Fenshui. In the temple, their legacy of water control is engraved: "Take the beach deep and make a weir at the bottom." There is also Fulong built on Lidui. It is said that Li Bing once subdued a wicked dragon that made waves here, so the temple was built to commemorate it.