Do you know the Yellow River Beach?

On the Safety Construction of the Yellow River Beach Area

Kou Geng Quan Ming

The floodplain of the Yellow River is an important area for sediment deposition and flood detention in the Yellow River, and it is also the only place for millions of people to survive. With the development of society, the total inflow of the Yellow River has decreased, the main channel has been silted up, and there are more opportunities for floodplain. How to strengthen the safety construction of the Yellow River beach, correctly handle the contradiction between flood control and beach development, and put forward that widening dikes, strengthening narrow river defense, resettlement to build towns, and flood diversion and silting beaches are effective ways to realize the flood control safety of the Yellow River and the people in the beach area to run towards a well-off life.

Key words: flood detention and sediment dike in Yellow River beach area

I. Overview of the Yellow River Beach Area

There are vast beaches on both sides of the wide channel in the lower Yellow River, with an area of about 3 1, 0 1 km2, accounting for 86% of the channel area. Divided by swaying river channels and production dikes, * * * forms1more than 20 natural beaches with different widths, 1.5 ~ 8.0 km. There are a large number of natural landforms such as gullies, depressions, dikes and rivers, beach protection projects and production dikes in parallel rivers, and artificial structures such as forests, villages, water shelters and houses scattered all over the beach. Each beach area is generally narrow from top to bottom and wide in the middle, and the longitudinal slope of the beach surface is basically the same as that of the corresponding river section. In recent years, the inflow water is seriously dry, and there are many opportunities for siltation and floodplain in the main channel. The flow rate varies from 2000 to 4000m3/s in different places. The gullies 1800m3/s flood may overflow, and some floodplains are flooded. Most floods with a flow rate of 4000m3/s may flood the floodplain, and all floodplains above 6000m3/s may be flooded. Especially in the reach from Dongbatou to Taochengpu, the transverse gradient of the beach surface is more than 3 times larger than the longitudinal gradient of the river, and the "secondary suspended river" is serious, and there is a danger that the flood will seize the flow and roll over the river and flood along the embankment.

Second, the beach safety construction needs to be strengthened.

After 1958 flood, in order to solve the safety of people's production, life and property in the beach area, low-standard and uneven quality production dikes were generally built spontaneously in the beach area of the lower Yellow River. After the completion of the production levee, the flood discharge channel will be narrowed, which is extremely unfavorable to the flood control of the Yellow River. In the State Council, (1974) Guofa No.27 document clearly stated that illegal buildings must be demolished, and people in the beach area began to build houses, village platforms and other water-proof projects in a planned way. However, due to the low engineering standard of the refuge platform, many quality hidden dangers, poor anti-flooding ability and seriously lagging progress, the production dike has not been abandoned so far. However, the production dike lacks reasonable planning and design, and there are many unreasonable places in flood control standards, dike line selection and section design. Some dikes even violate the law of river evolution and are laid in the beach area where floods are easy to scour, so there is no safety guarantee. Once the dike breaks, the people in the beach area will suffer serious losses. With the strengthening of "people-oriented" and building a well-off society in an all-round way, we should strengthen the safety construction in the beach area as soon as possible, so that the people in the beach area can live and work in peace and contentment and get rich as soon as possible.

Three. Some suggestions on safe construction in beach area

1. Widen the river course and reinforce the dike, and vigorously promote the standardized dike construction.

Strong dikes are the foundation and reliable guarantee means to ensure the flood control safety of the Yellow River. The vast beach area can effectively regulate and store large floods, deposit sediments, prolong the life of river courses and ensure the flood discharge safety of narrow rivers in Shandong Province. Further strengthen dikes, vigorously promote the construction of standardized dikes on the north and south banks, and ensure the overall flood control safety of the Yellow River when it encounters a flood of 22,300 cubic meters per second.

At present, the standardized dike construction should make a detailed project construction plan, and make clear the progress objectives of each stage; Strengthen and refine the management during the construction period; Thoroughly implement the project quality leadership responsibility system, improve the quality awareness of all parties involved in the construction, further improve the quality management system of "the government is in charge of a project, the legal person is responsible for the supervision unit, and the construction unit guarantees", strengthen quality management, strengthen supervision and inspection, and ensure the quality of the project. Further strengthen the standardized information management of dike construction, severely investigate and deal with quality problems in the process of engineering construction, and strive to ensure the quality and progress of engineering construction, and ensure that the quality and progress of engineering construction are completed as planned.

At the same time, speed up the construction of windbreak forest and improve the system of preventing the flat embankment from being washed by wind and waves; Strengthen the planting, renewal and management of the turf on the embankment slope to prevent the erosion and destruction of the embankment slope by rain; All water management units should earnestly do a good job in project safety management, and conduct project safety survey, hidden danger detection and root stone exploration on key river regulation projects in time to ensure the safe use of the projects.

2. The narrow river channel and weak defense protect the beach production to a certain extent.

In order to intensify river dredging, it is necessary to thoroughly remove tall crops, trees and other water-blocking objects planted by the masses on both sides of the river regulation project, so as to improve the flood discharge capacity of the river, reduce the flood level, reduce the roughness of the tender beach, increase the velocity at the same level and reduce the siltation of the tender beach, and formulate measures or conventions to prohibit planting. At the same time, we should face up to the fact that the inflow of water in the lower reaches of the Yellow River is gradually decreasing, and the probability of a major flood is greatly reduced. We should learn from the successful experience of the construction of Wenmengtan resettlement area of Xiaolangdi Water Control Project, make full use of the favorable conditions of river regulation, effectively control the change of river regime, improve the production and living environment of the beach area, and take the production levee as the first line of defense for flood control in the beach area for scientific planning and utilization.

3. River regulation and submission of Xiaoshui River

More than 50 years of river regulation practice has proved that small rivers with low water level are the root of large rivers with high water level, and there is no clear boundary between natural fluctuation and transition of different types of floods with low, medium and high water levels. Effectively regulating the low-flow river course can effectively affect the middle-water river course. At present, the operation of Xiaolangdi Reservoir faces a rare opportunity: the application of Xiaolangdi Reservoir greatly increases the duration of small water in the lower reaches of the Yellow River, and the occurrence probability tends to be stable. In the case of reservoir regulation, the duration of the flood is greatly increased, the probability of occurrence is reduced, and it can be stable. Using the long-term control conditions of small water, clear water and water diversion projects, a relatively stable small waterway is formed, with controllable flow, about 3000 m3/s and sediment concentration of 3 ~ 500.

4. Diversion of flood and siltation in high beach area to alleviate the unfavorable situation of secondary suspended river.

The Xiaolangdi Reservoir is used to adjust water and sediment to form a flood with high sediment concentration, and large-scale siltation is carried out in the beach area in a planned way, so as to raise the beach and fill the dike river, forming a high beach and deep trough conducive to flood control and sediment transport. Xiaolangdi Reservoir regulates the flood with sediment concentration of 300 ~ 5 mkg/m3, and the discharge is slightly larger than the reserved reach. By presetting 2 ~ 3 flood diversion gates and artificial diversion in each diversion project, the flood diversion from top to bottom will deposit the floodplain of each river section at one time, thus eliminating the unfavorable situation of "secondary river suspension". After the sediment deposition, the water volume will be controlled to return to the expected position and the main channel will be scrubbed.

It should be noted that the use of silt beach should be coordinated with the local government and residents in the beach area. The silt particles in the beach area are fine, which is beneficial to crop planting and land reclamation and the implementation of silt-free beach; It is planned to implement the policy of "one water and one wheat" in the silting year. After the accumulated water in the beach area is concentrated through dikes or ditches, the Yellow River levee will be used to pass through dikes and sluice holes, and then the water pump will be used to lead out the beach area in time, which will not affect the sowing of wheat after autumn.

5. Beach safety construction

The construction of reservoirs and underground rivers in the beach area should be safe, reliable, and use the beach area as much as possible to reduce losses. Starting from the overall situation of harnessing and developing the floodplain in the lower reaches of the Yellow River, the existing production structure is completely changed, and the floodplain is clearly divided into areas with completely different functions: most of them are very flood detention and siltation areas, and this part of the floodplain has changed from simple grain production to a production structure dominated by grain production, supplemented by the development of animal husbandry and economic forests, and the floodplain is operated and developed by farms or groups. A small part of the town development zone was built as immigrants, and the population in the beach area was concentrated in different areas. While the masses are engaged in agriculture, animal husbandry and forestry production, the surplus labor force in the beach area is encouraged to vigorously develop the secondary and tertiary industries, realize the urbanization development of the masses and run towards a well-off society. In order to solve the problems of small scale, low standard, unreliable quality, scattered people's residence and lack of material and financial resources for flood control in single-family villages, towns and villages where people are concentrated adopt high standards to avoid floods on the spot.

6. Accelerate the development of mobile combined diversion dam.

The distribution of soil quality in the lower reaches of the Yellow River is very irregular and random. Different soils have different water erosion resistance. In addition, due to the change of incoming water and sediment conditions and the small flow energy, temporary abnormal river regime similar to that in front of Caijisheng levee in September 2000 and Zaoshugou first beach in July 2000 often appears in the wider river channel with the regulation standard of 5000 m3/s and reserved flood discharge width. If the construction project is contained in time and allowed to develop, it may worsen the river regime and bring unexpected dangers and passive flood control to the project. A better measure is to use the movable combined diversion dam to temporarily adjust the temporary river regime. In addition, historical experience tells us that an effective measure for emergency interception of the Yellow River levee is to use diversion to change the unfavorable scouring conditions of water flow on the project or beach, and create better conditions for emergency interception of the project. Mobile combined diversion dam should be developed as soon as possible.

(Author: Yellow River Affairs Bureau of Henan Province)

Editor Wei Fengnian