Model essay on coping with water shortage of superior leaders

I. Current situation of urban water supply pressure in * * city

* * After more than 20 years of construction, the production capacity of water supply facilities has reached 60,000 m3/d, the total length of transmission and distribution water network is 1 18km(DN≥80mm), and the water consumption rate is 98%, which basically meets the urban water demand. However, according to "Urban water supply system should meet the requirements of urban water quantity, water quality, water pressure, urban fire protection and safe water supply" (Code for Planning of Urban Water Supply Engineering gb50282-98), there is still a big gap. At present, the most common and prominent problem reflected by the public is the lack of water pressure in the water supply network. The main reasons for this contradiction are as follows.

1, the existing water supply system has a low starting point and is inherently insufficient after urban expansion.

Jiangbei Waterworks, the main waterworks, was selected, requisitioned and finally scaled according to the general rules of the original county before the city was built. So far, it has not broken through the pattern of single water source, small water plant and dendritic water supply pipe network, and the water supply pressure is low. At first, the scope of water supply was mainly in the flat and low-lying areas on both sides of Dongba River (the high hillside area has not been developed), but in the 1980s and 1990s, most multi-storey buildings in urban areas were equipped with roof water tanks and pressurization equipment to adjust the uneven water consumption and water pressure day and night. Therefore, in the early stage of the construction of Jiangbei Waterworks, the supply exceeded demand, the citizens were satisfied and the government was happy, and many potential problems had not yet appeared.

After the withdrawal of the county and the establishment of the city, the general rules of * * have been revised several times, and the status of the city has been improved. The scope of water supply has rapidly expanded to the downstream and high-rise, and the number of buildings has generally increased, with more and more small and high-rise buildings. The original low-pressure water supply system seems to have a low starting point, and it is difficult to realize the transformation of water supply and safety improvement to medium-sized cities in a short time. Performance: 1, with multiple water sources, multiple water plants and emergency water sources; 2. The middle and far ends of the low-pressure pipe network should also be equipped with pressure compensation facilities; 3. After the urban cascade development, the topographic relief becomes larger, so the water supply mode of regional partial pressure should be adopted; 4. Re-rational layout and construction of a large-scale ring pipe network integrating production, living and fire fighting; 5. Many problems such as vertical zoning of water supply system in small high-rise buildings and high-rise buildings have become increasingly prominent, and the defects of the original water supply system cannot fundamentally solve the new contradiction between supply and demand after urban expansion.

2. The pipe network construction is lagging behind, and the water supply system is not completely matched.

Although the production capacity of Jiangbei Waterworks reached 50,000 m3/d after expansion and reconstruction, the construction of pipe network was not synchronized. Due to the lack of unified, scientific and strict planning in the construction of the original pipe network, the existing 1 18km pipe network is mostly small-caliber pipe network formed by "quick-acting" in small steps year by year, mostly dendritic. With the increase of water supply in recent years, bottleneck problems have emerged. Although the factory water pressure is 0.45mpa, it has dropped sharply to 0. 15-0.2mpa or even lower at the end of the pipe network. This is mainly manifested in Nanba area, Houheqiao area, Longquan area and the return air area at the end of the pipe network.

3. The damage of the high regulating pool directly affects the pressure regulation.

* * Water supply areas are mostly distributed in the middle and lower reaches far away from water plants. In order to make the water pipeline of the General Plant deliver water to the city more evenly, two brick-concrete high-level regulating tanks with a total volume of 3,500m3 were set up at Baiyun Station near Jiangbei Waterworks. In addition to regulating water storage capacity, its main function is to stabilize pressure. Due to the development and construction of the North Second Ring Road, the cutting off of the mountain around the pool and the blasting operation, the 1 pool (2,000m3) has cracked beyond repair, and only the No.2 pool keeps running at a low water level, which greatly weakens its water storage and pressure stabilization capacity. The amplitude and frequency of water pressure fluctuation in pipe network increase, especially in the peak period of water supply. At present, urban areas are not only under-pressure and short of water in high areas, high locations and high floors, but also lack of water supply pressure in low areas, such as Nanba area, Beimen area and Houhe community.

4. Sequelae of water supply in newly-built residential quarters are endless.

In recent years, with the transformation of the old city and the development of the new district, commercial housing groups in residential areas have mushroomed everywhere, most of which are small high-rise buildings with 7- 12 floors. However, the problem of water supply pressure has not attracted the attention of relevant personnel. From design, construction to completion and delivery, there is no water supply and pressurization facility in the building. Developers never seem to doubt whether the pressure of urban water supply network can be directly supplied to the top. In fact, the indoor and outdoor water supply system in the residential area is not perfect, the water supply facilities are not matched, and the water supply problems are endless. High-rise residents reported that the water heater could not be turned on and the toilet could not be flushed. Property management can't keep up, and the contradiction between water supplier and water user intensifies.

5. After the water supply mode of one household and one meter is changed, the required service head increases.

After the implementation of one meter for one household, centralized household registration is adopted on the first floor, and each household is equipped with a small-caliber (dn20) supervisor. Compared with the previous water supply mode in which each household has several large-caliber (dn40 or dn50) directors entering the kitchen, bathroom and bathroom respectively, the pipe diameter becomes smaller, the pipe length becomes longer, and the number of valves and accessories increases, which doubles the resistance loss of the pipe and users on the water distribution network take over the points. The user connection point mentioned in "Code for Planning of Urban Water Supply Project" meets the requirement of service head of 28m, which is equivalent to the minimum head required for supplying water to a six-story building, but in fact, the head required for "one household and one meter" in a six-story residential building is often much larger. Therefore, after the table is divided, many users report that the water pressure is insufficient.