The lower reaches of the Yellow River are the leading and bridgehead of the new Eurasian continental bridge. Taking Lianyungang, Rizhao Port, Xuzhou Station, Shangqiu Station, Zhengzhou Station and Luoyang Station as boarding points, it directly communicates with the Bohai Economic Zone in the east of China and the Yangtze River Delta Economic Zone, and becomes an outpost for implementing the national strategy of developing the central and western regions and promoting the economic take-off of the underdeveloped areas in the middle and upper reaches of the Yellow River.

(1) The lower reaches of the Yellow River are facing the double pressures of severe flood control and water shortage.

The per capita water resources and per mu water resources in this area are 20% and 25% of the national average, respectively, and the direct economic loss caused by the annual interruption of the Yellow River alone reaches 26.9 billion yuan. The threat of the Yellow River flood is another worry in this area. At present, the occurrence rate of major floods in the Yellow River basin with a discharge greater than 10000 m2/s has increased from 100 a to once every 20 years. The flood discharge capacity of the Yellow River decreased from 22000 m3/s in 1950s to 7600m3/s at the end of 1990s. Moderate floods may also cause great losses to people and property downstream, and it is almost a foregone conclusion to prevent accidents in flood rivers.

(2) The lower reaches of the Yellow River are densely populated and the ecological environment is fragile.

In the estuary area, due to the rapid accumulation of sediment in the Yellow River, since 1855, the area of the modern delta has expanded by more than 5,000 square kilometers, with an average of 52 square kilometers of land reclaimed from the sea every year. At this rate, Laizhou Bay may become an inland saltwater lake in 25 years, and may be filled up after 140 a, and the Bohai Sea will cease to exist in 2000.

(3) The uneven rise and fall of the earth's crust and the earth's rotation cause serious lateral erosion of the east (Shandong section) and south (Henan section) of the Yellow River.

According to statistics, from Dongbatou to Taochengbu 190 km, the east dike has 50 km riverbank and 18 dangerous section. On the other hand, the west levee has only 10 km dangerous levee, and there are 6 dangerous works, which shows the great difference. In the reach from Xiaolangdi to Taohuayu near 100km, the lateral erosion of the Yellow River has formed a large number of landslides on the Loess Plateau. Taking 1972 Mayigou, Gongxian County, Henan Province as an example, the length of the rear edge of the landslide reached 1500 m, and the amount of earth and stone moved reached 75,000m3, which forced the main stream of the Yellow River to move northward more than 500 m, and the depth of geological disaster was only behind the dust in the Three Gorges of the Yangtze River.

2. Geological background of the lower Yellow River

(1) The lower reaches of the Yellow River are located in the North China Depression.

The basement structure of the depression consists of a series of different forms of fault depression and fault uplift. The larger geological structural units are Jiyuan sag, Wuzhi uplift, Kaifeng sag, Neihuang uplift, Jiyang sag, Chengning uplift and Huanghua sag from west to east. Significantly, the Yu He River and the Yellow River, which operated stably for more than 3,000 years in the Qin and Han Dynasties, both passed through the basement uplift area. More interestingly, the Yellow River channel from Xiaolangdi to Taohuayu did not flow to the bottom of Jiyuan sag, but cut the uplifted Songji Mountain, forcing Mangshan Mountain to retreat southward by more than 1500m. The phenomenon of river dynamic geology shows that crustal uplift and river erosion can achieve dynamic balance under certain conditions.

(2) Large piedmont slope plain and diluvial skirt in front of Taihang Mountain and southwest of Shandong Province.

The tectonic environment in the piedmont area is mostly a strong subsidence area corresponding to the crust, and the local depth can reach several kilometers. These alluvial sediments, which are mainly sandy gravel, have good water storage space, which can replenish the limited transit water in flood season to form underground reservoirs, which is an effective way to alleviate the water supply for industry, agriculture and cities along the Yellow River.

(3) The uplift area of Sanmenxia Basin and Luo Yi Valley in the lower Yellow River during the Neotectonic period.

The area rises in mountainous units such as Zhongtiaoshan Mountain, Xiaoqinling Mountain and Xiaoshan Mountain, with an average rising rate of 4 mm/a. There are deep late Pleistocene Malan collapsible loess on the surface of these areas, and there are river gravel layers with a thickness of more than 30 m under Malan loess in most areas. This loose deposit is prone to landslide in flood season, which will shake the stability of the loess plateau, cause a large area of loess collapse and form debris flow. Therefore, under the action of hydrodynamic force, gravity erosion is the main mechanism of geological disasters in this area. In the Xiaolangdi reservoir area, the resulting large-scale landslide can instantly reduce the width of the river by two-thirds.

(4) The way out of the Yellow River flood.

The problem of the way out of the Yellow River flood has not been fundamentally solved, and it is still an indisputable reality that the Chinese nation is deeply affected by it. According to the prediction of relevant experts, the Yellow River may have a catastrophic flood of 49,000 ~ 55,000 m3/s in recent years. Because the maximum flood discharge capacity of Huayuankou Station (standard in 1950s) is only 22,300m3/s, and the maximum flood discharge capacity of the narrow reach below Dongping Lake in Shandong Province is only 10000 m3/s, if the Yellow River levee breaks, it will surely cause devastating disasters to the coastal social economy.

3. Feasibility Analysis of Realizing Hydrogeological Environment Balance

Feasibility Analysis of Planning Target of Flood Control System in Lower Yellow River (1)

Facing the fact that the probability of flooding in the lower reaches of the Yellow River is increasing, and the flood discharge capacity of the existing rivers is declining year by year, the analysis of the realization of the downstream flood control system objectives, including the standby rivers of the Yellow River, is as follows:

A. Feasibility analysis

There is an erosion terrace as long as 100 km from Shankou to Taohuayu of the Yellow River. Among them, the symmetrical terrace is 25 kilometers long. This phenomenon shows that the Yellow River current can still maintain a certain downward cutting erosion ability after the crustal uplift rate reaches 2 mm/a. Coincidentally, before the Han and Tang Dynasties, the 3,000-year-old mainstream line of the Yellow River was always located in Wuzhi, Henan-Inner Yellow, Hebei-Cangzhou. The river regime is basically stable under the control of the river regime defense project and the defense system combining guidance and defense. At this time, the swing interval of the main stream of the Yellow River is still in the basement uplift area, which shows that the weak uplift of the fault block in North China Depression can achieve a certain degree of dynamic balance between river siltation and river sediment carrying capacity under certain external conditions. Therefore, using high-precision remote sensing imaging and GPS technology, the relationship function models of eroded reach of the Yellow River, crustal uplift and river undercutting, topographic slope and river sediment carrying capacity are studied. According to geophysical prospecting and drilling data, there are standard reflection surfaces and unconformity surfaces at the bottom of Neogene in the study area. Combined with geodetic data, the crustal uplift or subsidence rate is calculated, and then the relationship between crustal deformation and channel change of the Yellow River is extended. It is technically feasible to find a relatively safe zone in the relatively uplifted section of the earth's crust to achieve dynamic balance.

B. Proposed plan

The flood discharge capacity of the modern Yellow River is decreasing day by day. In the past 200 years, the probability of catastrophic floods in the Yellow River has gradually increased, and the problem of solving catastrophic floods in the Yellow River has become more and more prominent. The phenomenon of river dynamic geology shows that crustal uplift and river erosion can achieve dynamic balance under certain conditions. The existence of dynamically balanced reach in the lower reaches of the Yellow River is of great significance to the regulation and route selection of the distributary channel of catastrophic flood. In view of this, several rivers should be selected on the hydrodynamic balance zone to solve the outlet problem of the catastrophic flood, so as to ensure the safety of the country and people's lives and property. Based on the above factors, we put forward the proposal of "Diversion Scheme for Extraordinary Flood in the Yellow River", that is, 2-3 backup rivers are selected as branch canals for flood diversion of the Yellow River:

A. Qinhekou-Wuzhi Uplift-Neihuang Uplift-Chengning Uplift-Entering Bohai Sea;

B) Use the old course of the Yellow River in the Ming and Qing Dynasties east of Lankao as a diversion channel;

C. Use Zhengzhou East Jia Luhe as a diversion channel.

(2) Feasibility analysis of the Yellow River sediment resources target.

Faced with the fact that the lower reaches of the Yellow River are rapidly silting up and Laizhou Bay will be filled up, the analysis of realizing the goal of sediment resources in the Yellow River is as follows:

A. Feasibility analysis

There is an old saying: "The Yellow River fights water, and mud ranks seventh." It can be seen that the sediment concentration of the Yellow River is unique among the rivers in the world. What needs to be updated is that the Yellow River sediment should not be regarded as a heavy burden, but as a valuable renewable land resource. For example, at the mouth of the Bohai Sea, while land is being built at a speed of 52 square kilometers per year, the coastal areas of northern Jiangsu are advancing to the mainland at a speed of 63 meters per year ... In order for the Yellow River to benefit future generations, we must start with the rational allocation of sediment, that is, the resource utilization of sediment.

According to related experiments, when the velocity of high sediment concentration flow is greater than 2.3 m/s, it cannot be guaranteed not to deposit. If the pipeline is used for transportation, the specific gradient will be reduced to110000, and the longest transportation distance can reach 1000 km. Black soil in Jiang Sha, Henan Province is mainly distributed in Zhoukou area of Huaihe River Basin. From Zhengzhou Huayuankou to Zhoukou Jiang Sha black soil distribution area, the terrain elevation difference is 45 m, and the terrain slope is as high as 1/4000. It is completely feasible to transport the Yellow River sediment to the black soil area of Jiang Sha with such a steep terrain. Therefore, the topographic conditions supporting long-distance sediment transport are the key to realize sediment utilization in the Yellow River. Using modern remote sensing information processing technology, DEM can be generated quickly in a large range, and the accurate terrain slope data required by sediment transport project can meet the requirements.

B. Proposed plan

Black soil in Jiang Sha is one of the main low-yield soils in North China Plain. In order to thoroughly control the black soil in Jiang Sha, we must break the traditional model, make full use of the high-sediment flow of the Yellow River for siltation, and thoroughly improve the structure of the black soil in Jiang Sha. From the point of view of geological forces, the high sediment concentration flow and the suspended river on the ground in the flood season of the Yellow River have created conditions for artificially controlling the sedimentary construction activities of the river. Nowadays, the suspended river on the ground has become the watershed between Haihe River and Huaihe River. The alluvial fan of the Yellow River takes the current river course and the ancient road of Ming and Qing Dynasties as the middle ridge and inclines to the east, northeast and southeast. The runoff network developed on it has actually become a natural channel for transporting sediment and water. If the Yellow River sediment discharge in Bohai Bay is reduced and the excess sediment is transported to northern Jiangsu, the coastal stability of Shandong and Jiangsu can be maintained. In the Huaihe River Basin, the terrain slope between Huaibei Plain and the suspended river reaches is generally around 4‰. If the river with a velocity greater than 2.3 m/s can not be silted, the pipeline transportation distance can reach about 1000km.

(3) Feasibility analysis of optimizing the target of underground water storage project in the lower Yellow River.

In the face of the shortage of water resources in the lower reaches of the Yellow River, it is difficult for plain reservoirs to play their role. The analysis of the realization of the optimal goal of the groundwater storage project scheme is as follows:

A. Feasibility analysis

At present, the limited water resources of the Yellow River are far from meeting the rapidly growing water demand along the Yellow River. According to incomplete statistics, the industrial, agricultural and urban water consumption along the Yellow River in 1950s was about 9500 Mm3. In the 1990s, it has reached 29000 Mm3, a two-fold increase. At the same time, the available water resources of the Yellow River decreased year by year, and the phenomenon of water cut-off began to appear in the lower reaches of the Yellow River in the early 1970s. In 1990s, the phenomenon of water cut-off became more frequent, including 83d of 1992, 122d of 1995, and 1996. The direct economic loss caused by the interruption of the Yellow River to downstream industry and agriculture is as high as 26.8 billion yuan per year. The problem of water resources has become an important factor restricting the economic development along the Yellow River.

In view of the existence of a large number of molasse buildings in front of Taihang Mountain, and the widespread leakage of groundwater in the wide Yellow River beach and Houhe depression, it is technically feasible to investigate and evaluate the water storage space of the piedmont diluvial skirt, ancient river highland and Houhe depression by using large-scale resource satellite digital images combined with geophysical, Quaternary geological, hydrogeological and borehole data.

B. Proposed plan

Facing the fact that water resources of the Yellow River are increasingly scarce, it is difficult for plain reservoirs to play an effective role. It is of great significance to determine whether an area can regulate and store groundwater for alleviating water supply and industrial and agricultural water use in cities along the Yellow River. In view of this, according to the special study of groundwater storage engineering in the lower reaches of the Yellow River (Henan section) 10 km, the zoning map of groundwater storage engineering along the Yellow River in Henan Province is compiled. According to the hydrogeological conditions, buried types of sand layers and lithologic distribution of vadose zone in the study area, the groundwater storage engineering division in the surveying and mapping area is divided into two types: shallow buried sand layer storage area and deep buried sand layer storage area, which consists of 16 storage sections. The water storage area of the two types of water storage areas is 5755.65km2 ... In terms of water storage mode, six shallow sand layers are replenished through the infiltration of rivers and canals; In the 10 sand layer deep buried water storage area, the groundwater funnel area is replenished by the mixed way of deep channel and shallow well infiltration. The maximum storage capacity of the two types is 4345.26mm3, of which the storage capacity of the north bank of the Yellow River 10 storage section is 2422. 19 Mm3, and the storage capacity of the six storage sections on the south bank of the Yellow River is 1923.07mm3. ..

Comprehensive investigation and evaluation of land resources in Henan Province by remote sensing

Comprehensive investigation and evaluation of land resources in Henan Province by remote sensing

Comprehensive investigation and evaluation of land resources in Henan Province by remote sensing

Comprehensive investigation and evaluation of land resources in Henan Province by remote sensing

Comprehensive investigation and evaluation of land resources in Henan Province by remote sensing