Every time it rains for a long time in Beijing, there is a lot of water in the streets. What is the current situation of urban drainage system in Beijing?
2 problems existing in urban drainage system
2. 1 Inadequate drainage standard and aging facilities.
According to the Code for Design of Outdoor Drainage (GB500 14—2006), the design standard of (3 ~ 5) is generally adopted for important urban trunk roads, important areas or areas where short-term water accumulation will cause serious consequences; The return period of drainage design of interchange road is not less than 3 years. The current drainage standard of urban pipe network in Beijing is generally: the drainage trunk line is about 1 a (36 mm/h) once, the branch line is only (0.33 ~ 0.5) a once (10 ~ 15) mm/h), and the urban loop line is (/kloc-). Of the 88 rainwater pumping stations, 65 have a return period of less than 2 years (including 2 years), accounting for 73.8%. The drainage standard of drainage facilities is low, far below the standard of extreme rainfall (70 mm/h), and the urban flood control and drainage pressure is extremely high.
Among urban drainage pipelines, l 200 krn was built before 1977, accounting for 1/4 of the total length of the pipeline, including the old brick ditch before liberation and the combined drainage ditch after liberation. According to the technical level of pipelines, the low-grade pipe network facilities belonging to Grade III and IV account for 27%. In addition, the operation of electrical equipment in some pumping stations exceeds 10 a, and the electrical components are generally aged and damaged, which reduces the safety factor and greatly reduces the reliability and sensitivity. The monitoring facilities such as automation, explosion-proof and ventilation system of some pumping stations can no longer meet the needs of today's industry management. The aging of facilities has greatly reduced the actual drainage standard.
2.2 The construction of drainage facilities is lagging behind and the drainage system is not perfect.
Because the urban river regulation lags behind the urban municipal main project construction, some drainage projects are not implemented at the same time or at the same time, resulting in no downstream and no way out for pavement drainage after the project implementation, and it will become a water accumulation point on the day of completion.
Some sections lack municipal rainwater drainage facilities, natural drainage facilities such as side ditches are destroyed or buried, and the rainwater drainage downstream of some sections has no way out or is not connected, so the pipeline cannot be put into use after completion. The rainwater pumped by some pumping stations is directly discharged into open channels or rivers. Due to serious siltation, when encountering heavy rainfall, rainwater overflows the river or open channel.
2.3 Water problems caused by urban construction.
(1) Rapid urban construction, with many projects under construction and a wide area, has broken and changed the original urban drainage system pattern, resulting in poor drainage and increased drainage load.
(2) With the continuous expansion of urban area, the ground is highly hardened, the surface runoff coefficient increases, and the output per unit area increases by 30% ~ 70%.
(3) Temporary construction measures are not in place, and the problem of temporary drainage of the project is not reasonably solved, and many new water accumulation points will be formed when it rains.
(4) The construction management is not perfect, and the problem of construction waste blocking the drainage pipeline is more prominent. At the same time, the construction disturbance causes the drainage pipeline to be damaged, broken, leaking, polluting the environment and causing public grievances.
2.4 Management defects lead to the lack of facilities to ensure safe operation.
Due to historical reasons, urban drainage pipelines, especially the rainwater and sewage confluence pipelines in the old city, are close to houses and buildings, and there is a danger that houses will collapse and hurt people, so it is difficult to maintain and transform them. In particular, the ditch section under the houses is more dangerous, and in recent years, the problem of broken covers and collapse has appeared many times.
Due to the lack of long-term maintenance and operation funds, the maintenance personnel of drainage facilities are insufficient and unstable, and the technical quality is low, which is far from meeting the increasingly standardized management requirements.
In addition, the rain outlets are often blocked by domestic garbage, especially some small and medium-sized Chinese restaurants, which usually discharge oil directly into the pipe network without oil separation measures, although they cannot be prevented from strengthening inspection. At the same time, the theft of rain grates also happens from time to time.
3 countermeasures
3. 1 Accelerate the construction and renovation of drainage system and strengthen daily maintenance.
3. 1. 1 Accelerate the construction and renovation of drainage system.
(1) evaluation of drainage facilities pipe network in the eighth district of the city, and gradually improve and transform the drainage system in combination with road reconstruction and expansion; Carry out the function and structure inspection of public drainage pipelines, improve the capacity of drainage facilities, and give full play to the overall benefits of the drainage system.
(2) Accelerate the renovation of drainage pipe network. Since 2006, the drainage pipelines and pumping stations with major hidden dangers and low standards in urban areas have been transformed by stages, so that the pipelines and pumping stations can be restored to the original design standards or higher than the original design standards.
(3) Accelerate the construction of water accumulation point renovation project. While building and renovating the drainage system, 43 municipal water accumulation point renovation projects have been completed one after another, basically solving the problem of water accumulation on urban roads.
(4) Accelerate the urban river regulation project.
3. 1.2 Strengthen the daily maintenance of drainage facilities
(1) Strengthen the maintenance of drainage pumping stations and pipelines, and complete the maintenance and dredging of drainage pipelines in non-flood season to ensure smooth water flow. Focus on cleaning and dredging drainage pipes, water-prone areas, municipal and property connection parts within the scope of various projects to ensure the integrity and normal operation of drainage facilities.
(2) Increase and popularize maintenance machinery, further improve the degree of mechanization of maintenance, enhance the ability of flood control, drainage and emergency disposal, improve the quality and efficiency of maintenance, and reduce the labor intensity of maintenance operations.
(3) Do a good job in pre-flood maintenance of flood control pumping stations, do a good job in preventive tests of power supply and distribution equipment, and improve various operating procedures, management systems and post responsibility systems to ensure the good operation of pumps.
3.2 Enhance the sense of responsibility and implement the responsibility of flood control.
Deeply understand the importance of flood control and drainage, and enhance the sense of responsibility of flood control and drainage. Further improve the flood control responsibility system, clarify the main body responsible for flood control and drainage, standardize the working procedures, strengthen the supervision mechanism, earnestly implement the responsibility system of the chief executive of flood control and drought relief, further clarify the responsibilities and tasks of various departments, and improve the overall efficiency of flood control and drought relief. Strengthen the supervision and inspection of the responsibility system, strictly enforce the discipline of flood control, establish an assessment system, find out the gap, grasp the implementation and promote improvement.
3.3 due to the destruction of fortification, revise and improve the emergency support plan.
According to the principle of "unified command, graded responsibility and professional disposal", from the reality, the urban emergency drainage plan is formulated and improved in advance, and the emergency command system and responsibilities, emergency response work contents at different levels, emergency dispatch, drainage and rescue measures, flood control and rescue responsibility system, rescue teams and materials are defined, thus forming a feasible and complete plan system.
3.4 Strengthen drills to improve the ability to deal with dangerous situations.
Strengthen the construction of professional teams in flood control and emergency rescue, do a good job in management training, strengthen service functions, improve technical equipment, and play the role of the main force in flood control and emergency rescue. According to the situation of water accumulation in overpasses and roads, improve and strengthen the system of urban emergency drainage responsibility area. According to the emergency drainage responsibility area, all emergency rescue units have established an emergency rescue mechanism of "arriving before rain, patrolling in rain, taking the initiative to rescue, and ensuring linkage", further strengthened the construction and drills of rapid emergency rescue teams, and improved emergency drainage and rescue capabilities.
3.5 Collaborative defense, forming a departmental linkage mechanism.
Flood control, meteorology, water affairs, transportation, traffic control, construction, municipal administration and news media work closely together, and under the unified command of the Municipal Flood Control Headquarters, six mechanisms are formed, namely, internal notification linkage of meteorological flood warning, reporting responsibility of road personnel on duty in rainy days, linkage of road traffic guarantee in rainy days, rapid elimination of water accumulation points, supervision of flood control responsibility and information submission. In case of flood control emergencies, all departments and units should communicate in time and respond quickly to minimize disaster risks and losses.
4. Objectives, requirements and prospects of urban flood control and drainage
4. 1 work objective
The goal of urban flood control and drainage in Beijing is to ensure the safety of people's lives and property and the safety of urban operation.
(1) Under the conditions of non-extreme weather and rainfall, clear the accumulated water in key roads such as loop lines, tie lines and radiation in time and continue to pass; Water conservancy projects do not break dikes, dams or gates; The masses are not in danger.
(2) Make every effort to ensure the safety of urban operation under extreme weather and rainfall conditions; Go all out to rescue and minimize losses and impacts.
4.2 job requirements
(1) The drainage facilities are planned and constructed according to the specialty of rainwater drainage system.
(2) The drainage facilities are in good condition.
(3) The drainage facilities are operating normally.
(4) The water storage and drainage capacity of the river meets the requirements of urban flood control and drainage.
4.3 Suggestions and prospects
(1) Accelerate the implementation of flood control planning and flood control projects. Urban flood control planning should be synchronized with the overall planning and given priority to implementation. The design standard should be moderately improved in the construction and transformation of pipe network. In combination with the development of old urban areas and road reconstruction and expansion, the old drainage pipeline will be upgraded in a planned way to improve the drainage capacity and implement rain and sewage diversion. Establish the idea of leaving a path for rainwater, build rainwater utilization facilities, stabilize flood peaks and save water resources.
(2) Strictly implement the urban flood control and drainage planning. The drainage system construction of the project under construction must be synchronized with the main project construction and brought into the unified management of the urban drainage network.
(3) Drainage is the focus of urban flood control work, and water accumulation points mainly appear on roads. According to the actual situation, rainwater branch lines and rainwater outlets are added to focus on solving a number of stagnant water points.