The Forbidden City also stores water in heavy rain
Encountered by the heavy rains that appeared in Beijing a few days ago, the Forbidden City is not "dropping water" as described in the wind and the wind.
On July 20, a "crossroads" at the Imperial Garden of the Forbidden City, with an insole floating in a small puddle, became a photographic highlight for many tourists.
As a "thousand dragon spitting water" of the Forbidden City, near noon on July 20, in the pouring rain, there were three or four faucets in the row under the steps of the Zhonghe Temple, which still locked the "dragon mouth", and two only ticked. The ground is dripping, but some gaps between the railings and the steps spray water out. In the Forbidden City, the Taihe Hall, Zhonghe Hall and Baohe Hall are placed back and forth. They are located on an I-shaped three-story platform with a height of more than 8 meters. There are drainage holes at the bottom of the railing around the platform. There is a stone faucet with a round hole in the mouth, which is also the main drain. These dragon heads are called hoe heads or horned beasts. They spit water like Bai Lian during heavy rain and icicles during light rain.
Outside the Cining Palace, the stagnant water did not pass over the feet for a while, and several security guards marked the non-slip tips in the doorway to remind past visitors; there were also many small puddles on the ground in the area of the three halls.
Last month, a main rainwater pipe on the west side of the Royal Garden was found blocked and full of waste.
In this regard, Shan Xiangxiang explained one by one.
Waste is the enemy of drainage systems. Beverage bottles and napkins thrown away by the audience often blocked some drains. When it rains, the operator needs to wade through the water and pull out the debris with his hands. "But soon after finishing, the drain will be blocked by new debris."
Dragon mouth spouting water needs to accumulate a certain amount of water. However, the ancient fence and the first year of the crotch are already high, and each year they must "tick teeth". "The sensation during the finishing process may lead to cracking of the bow head, so you cannot use strong things to clear it, you can only use a bamboo stick to organize it little by little."
And some of the water is caused by the later laying. "Some ground unevenness is to maintain the original appearance, and some is due to a large number of ground paving has been changed to impermeable concrete ground and asphalt pavement, which is not conducive to drainage and water seepage. "
Changed " pervious bricks " most of the year
"Each rainfall process is the best opportunity to discover the problem. The museum uses the dry season to make and summarize the distribution map of water accumulation points in the hospital, analyze the causes of water accumulation, and discuss and summarize solutions." Shan Yanxiang said.
Regarding the accumulated debris, such as leaves and muck, in the rainwater ditch, the Palace Museum will arrange manual excavation and replace the damaged and broken trench cover. The other Forbidden City will replace the eastern pipeline of the Royal Garden, and conduct special investigations and reorganization of rainwater pipe ditches in other areas such as Xi Liugong. Since the previous year, the Palace Museum has gradually changed the cement floor and asphalt pavement of the hospital to traditional construction materials such as masonry. It is estimated that most of the cement floor will be replaced with " pervious bricks " this year, and the traditional pavement will be completely restored next year. For the uneven ground, the Palace Museum will dug in time.
The drainage system of the Forbidden City now uses the original ancient rainwater system. For this drainage system left by the ancestors, the Forbidden City also launched a special project discussion.
According to statistics, the length of the ancient rainwater ditch still in use at the Forbidden City is over 15 kilometers, and the length of the ditch is nearly 13 kilometers. The Forbidden City conducted investigations in the entire area of Yongshou Palace, Kun Kun Palace, and Chu Xiu Palace in the area of Xi Liugong Palace, Yangxin Palace Courtyard, Qianqing Gate, and Longzong Menqian Square. A total of 7 types of rainwater outlets and 64 were found. 53% of them were single-hole vertical without grille type. According to the planning requirements of the grid-type rainwater outlets used in cities now, all the rainwater outlets in the Forbidden City not only passed, but also exceeded the maximum value claimed by the planning specifications.
However, experts have found that the original ancient rainwater system in some areas was damaged or difficult to perform its original function through the construction activities of different dynasties. Regarding these drainage systems, the Forbidden City will complete a "cleanup" within 4 years. For example, for some river gangs to bulge and shift, some drainage ditches appear to be partially collapsed, and repairs will be implemented to ensure the smooth flow of river water; for some rainwater ditches to be full of silt or debris, the drainage will be reduced. In time, it is necessary to eliminate the obstructions under the railing, in the middle of the bow, and in the drainage holes. For some drainage ditch covers or drainage openings that are damaged and lose the function of blocking debris from entering the drainage system, the trench will be repaired and replaced in time. Trench cover and gully. In addition, weeds must be pulled in time to prevent weeds from blocking drainage outlets during concentrated rainfall and severely affect drainage capacity.
At present, the Forbidden City has incorporated 15 kilometers of ancient rainwater ditch into the ancient maintenance and repair project.
The Jinshui River will be opened to release water during heavy rain
The National Palace Museum also formulates the "Flood Prevention Emergency Plan" every year, and establishes day and night duty guidelines for flood prevention.
The museum has divided the flood warning information into four levels: general, heavier, severe, and particularly severe, which are represented by blue, yellow, orange, and red in turn.
Once the orange flood warning is issued, the Forbidden City will reduce or stop ticket sales based on the actual situation, and adopt measures such as agile transfer, evacuation, or dispersal of audiences. When the red flood prevention warning is issued, the Forbidden City will immediately adopt corresponding measures to form a rescue team and harmonize relevant parts to participate in emergency operations.
"We also set up a contact with the River and Lake Management Office of the Beijing Municipal Water Affairs Bureau to investigate the water level of the Jinshui River at any time during the dry season. After the gate is opened, we can adjust it. For example, water will be released when the red warning is issued." All members of the Forbidden City will take up their posts, divide the work according to the piece, and timely clean up the debris floating upstream to the drainage outlet. "
Forbidden City 2 meters north to south
The Forbidden City is a royal project, with a sophisticated drainage system. Shan Xiangxiang commented: "The capital of Beijing faces Yanshan in the north and the Bohai Sea in the east. The terrain is high in the north and low in the south, so the water flows to the southeast. The trend of the Forbidden City is the same, with the center high and two low."
According to the data, the level of Shenwumen in Beimen is 46.05 meters, the level of Wumen in Nanmen is 44.28 meters, and the vertical height difference is about two meters, which has created favorable conditions for natural drainage.
Together, the courtyards of the palaces of the Forbidden City have drainage systems, such as dry ditches, branch ditches, open ditches, dark ditches, culverts, and Liushui ditch eyes. Whenever it rains, part of the rain falls along the glazed tiles on the roof of the building, and then flows along the open ditch to the entrance of the dark ditch; part of the rain directly constitutes surface runoff and flows into the stone trough open ditch around the yard and the base of the house. underground drain.
Rainwater enters the ditch, and there is naturally little water on the surface. According to statistics, the length of the ancient rainwater ditch still in use at the Forbidden City is over 15 kilometers, and the length of the ditch is nearly 13 kilometers, accounting for more than half.
After all, the rainwater was discharged into the Neijin River. This river flows from the sluice on the west side of Shenwumen, flows from the northwest to the southeast, flows through most of the Forbidden City, flows from the southeast corner, and merges into a 52-meter-wide Zhihe River. Later, the Tongzi River communicated with surrounding water systems such as Waijinshui River and Zhongnanhai.
Not only that, the internal drainage system of the Forbidden City also constitutes the separation of rain and sewage. The sewage system is an independent pipeline connected to the municipal pipe network. The drainage system is only used to remove rainwater.