Renovation effect of Shenyang stagnant water point is obvious and water withdrawal is fast

 Renovation effect of Shenyang stagnant water point is obvious and water withdrawal is fast

Rainstorms are increasing

Torrential rains, deep water, people in danger of extinguishing vehicles, people in the wind and rain to persevere in rescue, there are people who continue to fight unremittingly... To this day, people still remember the heavy rainfall on August 16. According to the Shenyang Meteorological Bureau, the heavy rain was the strongest hourly rainfall intensity since 1951 when Shenyang had complete meteorological data.

Last winter, it hardly snowed in the northeastern city of Shenyang. In such a strange climate, the Municipal Water Administration requires all flood control departments to increase their preparations for emergency links before the beginning of the flood season. Nevertheless, such a heavy rain was unexpected. The head of the Drainage Department of the Municipal Water Bureau told reporters.

According to the latest data provided by the meteorological department, from June 1 to August 23, the cumulative rainfall in Shenyang was 551.3 mm, 1.5 times that of the same period in previous years (372.9 mm), 2.7 times that of the same period last year (207.1 mm). Heavy rainfall occurred frequently, up to 30 times, especially from August 13 to 15, which was affected by the ultra-strong typhoon Liqima. After three days of continuous rainfall, the average rainfall in the city totaled 106.4 mm, and the maximum rainfall was 204.3 mm, resulting in a sharp increase in soil saturation and surface water confluence.

To make matters worse, it rained heavily on August 16 the next day, which was called the strongest short-term rainfall in 68 years by Shenyang meteorological circles. The maximum hourly rainfall was as high as 100.8 mm. For example, if you wash vegetables at home and the tap is running slowly, you dont need to think about it at all, and the pool wont accumulate water, but if you fill the basin with water and pour it into the pool instantly, the water wont go away at once. City Water Bureau experts told reporters.

This once-in-a-century rainstorm, which lasted only one hour, interrupted traffic on Hunnan Avenue, Nanwugong Railway Bridge, Nanbagong Railway Bridge and BeiErgong Railway Bridge, and stranded many weekend gatherers. At that time, the rainwater could not be discharged at all. The cover of the drainage well was washed away and the water column was several meters high. Li Wenwen, a water drainer on duty under the Second Street Highway and Railway Bridge in Tengfei on the evening of 16th, recalled the scene at that time.

If it rains 100 millimeters a day, Shenyangs roads will not be flooded, but if it comes down in an hour or half an hour, let alone Shenyang, foreign cities can not avoid it. Planning expert Liu Yuan told reporters that in recent years, Shenyang has built more and more high-rise buildings, asphalt roads, city squares, overpasses, parking lots and so on, making the bare land in urban areas less and less. Once it rains, it is difficult for rainwater to infiltrate into the ground. When rainstorms occur, runoff is formed and accumulated, especially in low-lying areas in urban areas, before rainwater can run through sewers.

For many Shenyang flood control personnel, if there are five words short-term strong rainfall in the weather forecast, it means that there will be a dangerous situation. The data show that in the 1950s and 1960s, the occurrence probability of such heavy precipitation in China accounted for 10%-15% of the samples, while after 2000, the occurrence probability exceeded 20%. Especially in mega-cities, under the catalysis of heat island effect and rain island effect, small-scale and high-intensity local rainstorms often occur in cities, which is easy to cause waterlogging disasters.

Fan Liguo, senior engineer of the Central Meteorological Observatory, told reporters that according to meteorological data, the concentration of precipitation in China has increased in the past few years, regardless of whether the precipitation is increasing or decreasing. That is to say, there will be more chances of heavy rain and heavy rain in the future, while the amount of continuous rainfall will be relatively reduced. Population concentration to cities will be a major trend in China in the coming decades. At the same time, global climate change is also a major trend in this century. These two trends confirm that urban flooding disasters are and will increase. This phenomenon has been particularly evident in recent decades. Fan Liguo said.

Aging Drainage Pipelines

Municipal rainwater pipes are laid under each road. Look at therainwateron the cover of this well. Here it is. Lu Jian told reporters at the edge of a well on Nanwu Road. Since serving as director of the garden community in the street city of Maluwan, Heping District, Lu Jian has often been busy with community waterlogging and has gradually clarified the underground drainage system.

This is the most common way of laying underground drainage pipelines in Shenyang. Municipal rainwater pipelines under each road, like the trunk of a tree, stretch out numerous thin branches on both sides, connecting a leaf - rain outlet. Experts from the Municipal Water Bureau told reporters that there would be a pair of rainwater side wells every 30 meters on both sides of a general road, and the arrangement would be more intensive at the corner of the road.

Shenyangs drainage system can be seen as two levels, just like the arteries and capillaries of the human body. Experts say that the water catchment system laid under the road is like a dense capillary, after collecting rainwater, it will merge into the artery - the canal and Hunhe River. Therefore, any link of the drainage system has problems, which will lead to pavement water accumulation.

The first link is the road rainwater outlet. Once the leaves and other debris are blocked, the rainwater can not enter the sewer smoothly, and the roadside is bound to accumulate water. In addition, problems often occur in pipelines. Rainwater branch pipe will be flattened for various reasons, resulting in rainwater can not enter the main pipe smoothly. Experts say that even the main pipeline under the road is not safe. For example, in urban construction, pipelines are often broken or blocked, but not handled in time. Once it rains, it will inevitably lead to nearby water accumulation.

In the short-term heavy rain on August 16, many netizens took pictures of many rainwater wells not only unable to drain water, but also turned into fountains. There are many reasons, but the key is that rainfall exceeds drainage capacity. Experts say.

It is understood that the current standard for the construction of urban drainage facilities in China is that the recurrence period of design rainstorm for drainage facilities in general urban areas is 1-3 years (that is, to withstand the rainstorm once in 1-3 years), and only 3-5 years for important areas. Although the standard is not very high, most areas of Shenyang are still not up to the standard. Take the main urban area on the Bank of Hunhe River as an example, the drainage canals built before the 1980s accounted for more than 70%, and their capacity to withstand heavy rains was only 0.5 years.

In addition, most of the old urban areas in Shenyang still adopt the rainwater-sewage confluence drainage system. The design method still follows the design theory of the former Soviet Union in the 1950s. The drainage of rainwater is too much considered in the design, and the hydraulic gradient is generally smaller, which results in a large number of silting pipelines in the sediment, garbage and slurry of construction in the dry season. It is difficult to clean up and maintain, resulting in poor drainage capacity.

In fact, due to the aging of drainage pipes. In the face of heavy rains, Shenyang has to rely more on manpower to waterproof and drainage. Before the arrival of Typhoon Lichma, the Municipal Water and Drainage Group dispatched 450 people, 150 equipment and vehicles to control each easily accumulated water point in addition to the routine actions of repairing pumping stations and cleaning pipelines. Take the key take-off Second Street, we not only drove the pump truck with 3200 cubic meters/hour of drainage in advance, but also arranged 3-4 mobile pumps, equipped with 10 people. Municipal Water Group responsible person told reporters.

In this Lichma rainstorm, although Shenyang experienced the helplessness of looking at the sea, it was also touched by the dedication of flood prevention people, such as fire fighting, traffic police, drainage and sanitation. On August 13, Master Chen, an employee of the Western Company, jumped into the drainage well and immersed in the cold sewage for two hours in order to dredge the blocked drainage pipe as soon as possible and make the stagnant water point unobstructed as soon as possible. His photos became a hot topic on the Internet today. Many netizens left messages saying that they preferred Shenyang.

The number of water accumulation points decreased from 138 to 62

In the face of heavy rain, although Shenyang has established a complete emergency system, it is urgent to reform the drainage system if we want to eliminate the sea-watching mode fundamentally. However, the transformation of drainage system is much more difficult than that of traffic. Traffic can be uphill or downhill, where it is stuck, where it can be relaxed, but the pipeline is not good. Thickening pipeline must be whole line thicker, only part thicker, no use at all. Secondly, the pipeline needs a gradient, which is getting lower and lower in order to ensure water outflow, so it is difficult to transform the drainage system, not a problem that can be solved in the short term. Liu Yuan told reporters.

The same is true. In the past two years, although Shenyang rainstorm waterlogging has become a routine, the story plot has changed a lot. For example, waterlogging has begun to appear in Hunnan and Changbai new urban areas, but it has eased this year in areas such as Huanggu and Dadong, where waterlogging was serious before. When the drainage and waterlogging project was carried out last year, many people scolded for occupying roads, but this year there was no water. Everyone was very happy. Zhao Yuhuan, a resident of Liutiao Lake community, told reporters.

Under the Liutiaohu overpass, it was a famous water accumulation point in Shenyang. In the past, in order to quickly remove the accumulated water, the city water drainage group parked the best drainage truck here. The car drains 6,600 cubic meters per hour, the worlds largest multi-functional self-priming drainage vehicle. Last year, in order to drain water, the blue hoses connected to the car were laid hundreds of meters away in canal canals. Li Wenhai, who is responsible for the drainage, said.

As the largest city in Northeast China, Shenyang accounts for almost all the causes of urban waterlogging. In early 2017, the Ministry of Housing and the National Development and Reform Commission issued the Notice on the Construction of Drainage and Waterlogging Repair Boards in Cities, listing Shenyang as one of the 60 cities with serious waterlogging disasters in China. In order to solve the problem of urban waterlogging, last year Shenyang formulated the Action Plan for Drainage and Waterlogging Prevention and Repairing in Shenyang (2018-2020). Through three yearsefforts, the drainage capacity of drainage channels, regional drainage (rainwater) trunk lines and pumping stations in key urban areas will reach the national three-year once-in-a-year standard by 2020, and the three-year once-in-a-time standard will be reduced. When it rains, the ground will not be flooded; when it rains below the standard once in 50 years, it will be realized that waterlogging disasters will not occur in key urban areas.

Last year, Shenyang Water Group completed 51 projects, including 15 new rainwater trunk lines such as Kunshan Road, Linhe Road, Gongnong Road, 21 pumping stations such as Beiling and Songhua River, widening and renovating the outlet of the lower reaches of the North Canal, and constructing Liutiaohu Lake, Wanghua Overpass, Linghe Road, North Second-class Key Regional Water Transfer and Storage Pools. Fifty-five scattered waterlogging sites have been improved, 119 rainwater drainage channels have been set up along the canal, and rainwater feeder lines have been reconstructed in conjunction with rainwater trunk lines. The change in the wicker Lake region has benefited from this.

According to reports, through the construction of the first phase of drainage and waterlogging control project, the drainage capacity of Shenyang trunk line system has been greatly improved, and the flood discharge capacity of the lower reaches of the canal has been significantly improved. The old Liutiaohu Railway Bridge, Wanghua Bridge, Liangkong Second Street Bridge, North Second Road Railway Bridge, Shenda Zero-kilometer and other important water accumulation points have been effectively solved due to the full play of the new reservoir in the flood season this year. The number of water accumulation points dropped from 138 last year to 62 this year.

This years drainage and waterlogging control project in Shenyang is still in progress, and next year, this years project will play an important role. Municipal Water Group responsible person told reporters. According to reports, a batch of construction projects of the second phase of drainage and waterlogging control in Shenyang this year totaled 32 projects, including 6 major systems, 27 new pipelines and canals and treatment projects of sporadic water accumulation points, and 5 new and improved pumping stations. After the completion of these projects, 25 water accumulation points will be thoroughly solved, such as the Third Ring Area of North Street of Yalu River, Beidaying Area, Yuhong New Town Area, Guangye Road, Lingdong Street, West Street of Lingyuan, Xinhua Road, Democracy Road, Literature and Art Road, Glorious Street, Liaoshen Second Street, East Station Street and Tengfei Second Street.

We are now working with the Urban and Rural Construction Bureau to organize a team of experts to further systematically demonstrate the water-prone problems in the areas with weak drainage, and to formulate a feasible project implementation plan, which will be included in the next stage of the urban construction plan for drainage and waterlogging prevention. With the continuous advancement of these projects, the Shenyang drainage system will be further improved and the waterlogging problem will be greatly alleviated. Finally, the head of the Drainage Department of the Municipal Water Administration said.

(function () {(window. slotbydup = window. slotbydup | []). push ({id:6374560, container:ssp_6374560, size:300,250, display:inlay-fix, async: true});} (); source of this article: responsible editor of Shenyang Evening News: Luo Chongwei_NB12082