Shuibatang weather forecast

Reasons for frequent floods in the Yangtze River: 1. Flood control scheme for soil erosion: comprehensively control soil erosion and strengthen river regulation.

2. The area of natural lakes is reduced and the flood storage capacity is reduced. Flood control scheme: returning farmland to lake.

3. Centralized flood control scheme for heavy rainfall: build more flood diversion and storage projects.

In addition, in view of other situations, we can also: vigorously publicize and make people establish the awareness of protecting the Yangtze River; Accelerate the legislative work to protect the Yangtze River.

First, the meaning and classification of floods and flood disasters, as well as the main types of floods in this area.

Flood is a natural hydrological phenomenon, which refers to the sharp increase of river water volume and water level. The formation of floods is often influenced by natural factors such as climate, underlying surface and human activities. It can be divided into river flood, tidal flood and lake flood by region; According to the causes, it can be divided into six types: rainstorm flood, snowmelt flood, glacier flood, ice flood, mixed rain and snow flood and dam-break flood. When the flood threatens human security, affects social and economic activities and causes losses, it forms a flood disaster.

This area is mainly caused by rainstorm and flood, which is usually caused by heavy rainfall. According to the causes of rainstorm, it can be divided into thunderstorm flood (also called sudden rainstorm flood), typhoon rainstorm flood and frontal rainstorm flood. In addition, dam-break floods, flash floods and mudslides are mostly caused by heavy rains.

Second, the causes and meteorological factors of mountain torrents

Like other natural disasters, the disaster-causing factors of mountain torrents have dual attributes of nature, economy and society, which are embodied in the fact that their formation and development are mainly influenced by rainfall and rainfall intensity, topography and geology and human economic and social activities.

Meteorological factors affecting mountain torrents: (1) Pacific subtropical high. Its location, intensity and activity directly affect the summer rainfall in mainland China. Long-term, high-intensity and large-scale storms and floods often occur at the northwest edge of the stable and inactive subtropical high. 1999 "9.4" flood occurred in Ouhai, which was the result of strong and stable subtropical high and little movement. (2) front rain. The cold air in the north meets the warm air in the south, forming a strip with high temperature, high humidity and low density, which is lifted to the sky by the cold air and forms frontal rainfall. (3) Shear line effect. The line with discontinuous wind direction in high altitude wind is called shear line (such as between southwest wind and southeast wind, or between south wind and north wind). There is a strong upward movement near the shear line, which is prone to heavy rainfall, and most of the rainstorm areas are distributed near the shear line. (4) Vortex. Vortex whose air pressure is lower than its surroundings is called vortex on the high-altitude weather map. The vortex that affects our country is often cut off by the extension trough of the westerly belt, or the airflow is generated after passing through a specific terrain. It is divided into North China Vortex by region. (5) Cyclone. Cyclone refers to the area where the ground pressure is lower than the surrounding area, that is, low pressure. In the cyclone center, due to the interaction of cold and warm air, heavy rain or heavy rain often occurs. (6) Typhoon. Typhoon is one of the main causes of rainstorm and flood. "Typhoon" is a warm vortex with a diameter of hundreds of kilometers generated in the tropical ocean of the western Pacific Ocean. According to the World Meteorological Organization, when the maximum wind force near the vortex center is less than 8 (that is, the wind speed is13.9 m2/s ~17.1m2/s), it is called "tropical depression". When the wind reaches 8-9 (that is, the wind speed is 17.2m2/s ~ 24.4m2/s), it is called "tropical storm". When the wind reaches 10 ~ 10 (that is, the wind speed is 24.5 m2/s ~ 32.6 m2/s), it is called "severe tropical storm"; When the central wind reaches 12 (the wind speed is above 32.7m2/s), it is called "typhoon". When the typhoon landed, it was very windy and rainy. If we go deep inland and interact with the westerly belt system in the middle latitude, a heavy rainstorm will occur, resulting in disastrous rainstorm, flood and flash flood.

Three. Causes and characteristics of frequent mountain torrents

The frequent occurrence of mountain torrents is closely related to climate and geographical conditions. China has obvious monsoon climate characteristics, with north wind blowing in winter and dry air; In summer, the south wind blows and the air is humid, and the rainy season mostly occurs during this period. Generally speaking, frequent mountain torrents are mainly affected by monsoon climate for three reasons. (1) The rainfall time is concentrated and the intensity is high. Most areas are controlled by monsoon climate, and most of the annual precipitation is concentrated in the humid and high temperature period in summer, mostly in the form of typhoons and rainstorms. The rainfall from June to September accounts for 60%~80% of the normal annual rainfall, which is often concentrated in the process of several heavy rains. (2) The seasonal displacement of monsoon rain belt leads to the periodic stability of rainfall area. The summer monsoon begins in May and advances from south to north. There are three corresponding rainy seasons, namely South China rainy season (April-June in southern provinces), Jianghuai rainy season (June-mid-July in the middle and lower reaches of the Yangtze River) and Northeast rainy season (July-mid-August in northern and northeastern provinces). At this time, the monsoon reaches its strongest. After September, the monsoon weakened and retreated south, and the rain belt gradually retreated south. 10 months later, the monsoon leaves Chinese mainland and the rainy season ends. Secondly, frequent typhoon activities in summer and autumn are also the main reasons for the formation of flash floods. After the typhoon landed on the coast, it generally turned north at around 300N~350N, and the wind speed gradually slowed down, forming a low pressure. If it is combined with the cold air in the north, it may form a wide range of heavy rains, floods and flash floods. In addition, the broad masses of cadres and people are not aware of disaster prevention. Large-scale activities such as mining, quarrying, road construction and canal digging affect the stability of the mountain, and the construction of development projects causes a lot of soil erosion, which is also the main cause of mountain torrents.

Mountain torrents have the following characteristics: first, they are sudden and difficult to predict; Second, it is fierce, fast and destructive; Third, strong seasonality and high frequency; Fourth, the area is obvious and prone to occur; Fifth, the scope is concentrated and it is difficult to recover after the disaster.

Four, mountain flood disaster prevention measures

(a) to scientific prediction, timely prediction.

This year, flash floods broke out. From May 3 1 day to June 1 day, heavy rains and flash floods occurred in Hunan, Guizhou and Heilongjiang, causing serious losses. Flash floods are sudden, and it is impossible to prevent them. Governments at all levels and relevant departments should adhere to the people-oriented and prevention-oriented principles, carefully study the characteristics and laws of mountain torrents, scientifically and rationally plan defense countermeasures, plans and emergency plans, and scientifically defend against sudden natural disasters. Before the rainy season comes, water conservancy, meteorology, hydrology and other departments should strengthen cooperation with land resources and other departments, do a good job in forecasting rain and water conditions, do a good job in forecasting heavy rainfall and floods in time, and report to the local people's government (and its flood control and drought relief headquarters) and the competent department of geological disaster prevention and control and relevant units. In case of emergency, notify all enterprises, institutions and the masses as soon as possible, and transfer the masses in advance when there are signs of danger, so as to ensure the safety of people's lives and reduce the loss of mountain torrents.

(two) to increase publicity and popularize common sense of disaster prevention.

A more effective way to prevent mountain torrents is to increase the popularization of common sense and knowledge of mountain torrents, grasp this work well, and truly spread it to every village and villager. Enhance the self-protection ability and awareness of the broad masses. Let the masses use scientific and practical flood control knowledge to avoid disasters and rescue, which is the best way. The masses have a sense of self-protection, and understanding the causes and characteristics of mountain torrents will enhance their vigilance. In the case of sudden flood, the village should make clear a series of self-help work such as evacuation routes.

(3) Strengthen law enforcement management and standardize project construction.

First of all, we should standardize the construction of mountainous areas to avoid the influence of mining, quarrying, road construction, canal digging and other activities on the stability of mountains and the hidden dangers of geological disasters in mountain torrents. In addition, it is necessary to strengthen the construction management of towns and settlements in mountainous areas, avoid building houses in dangerous areas such as flash flood-prone areas and low-lying areas along rivers (streams), and effectively reduce the losses caused by flash floods.

(4) Establish and improve the early warning system.

First of all, we should implement disaster prevention inspectors, make use of the human resources of Shantang Reservoir inspectors, strengthen the training of their common knowledge and early warning knowledge about mountain torrents, and equip them with corresponding communication tools so that they can have certain knowledge of disaster prevention and have the tools to communicate in time. Secondly, when inspectors find sudden short-term heavy rains and flash floods, they should immediately report to the local (or superior) government, its flood control and drought relief headquarters and the downstream people. After receiving the alarm, the local (or superior) government and its flood control and drought relief headquarters immediately consulted, started the early warning and forecasting system and disaster prevention plan in time, and formulated practical emergency measures for disaster relief. So as to grasp the initiative of emergency evacuation, reduce casualties and property losses and minimize disaster losses.

(5) Strengthen the supervision and management of soil and water conservation to reduce the occurrence of mountain torrents from the source.

First of all, it is necessary to strengthen the supervision of projects under construction. If the project under construction does not take practical measures, it will cause a lot of soil erosion. Only by strengthening supervision and urging the construction unit to do a good job in soil and water conservation according to the soil and water conservation plan can soil erosion be effectively reduced. Secondly, it is necessary to restore the damaged vegetation in mountainous areas, improve the rainwater conservation capacity in mountainous areas, slow down the speed of surface runoff after rainfall, vigorously carry out afforestation, close hillsides to facilitate afforestation, and return farmland to forests, and do our utmost to reduce the occurrence of mountain torrents.