River network discharged 540 million cubic meters
- Category: Governmental News
- Published: Monday, 19 August 2019 08:56
"The typhoon has left Ningbo, but the river network is still at a high water level, and the drainage cannot stop." On August 11, Li Liangyu, a staff member of the Municipal River Management Center, said. From 8 am of 7th to 8 am of 11th, the city's river network accumulated 540 million cubic meters of drainage, equivalent to the water volume of four Baixi reservoirs. Among them, Yaojiang Second Channel (Cijiang) drains 46 million cubic meters.
From August 5th, a drainage campaign quietly started in the city. Under the guidance of the Municipal Water Conservancy Bureau, the major reservoirs and river networks are pre-discharged, and the water volume is
accurately dispatched according to the movement of typhoon, so as to release the flood storage capacity as much as possible. At 11 o'clock on August 8, with "Lekima" approaching, Baixi Reservoir pre-discharged at a flow rate of 200 cubic meters per second; at the same time, Jiaokou Reservoir pre-discharged at a flow rate of 30 cubic meters per second; at 14:30, Hengshan Reservoir was pre-vented...
"According to the meteorological forecast and the specific trend of the typhoon, 32 large and medium-sized reservoirs are pre-discharged in a unified order and flow control." The relevant person in charge of the Municipal Water Conservancy Bureau introduced. The water flowing down from the river network from west to east, the river sluice along the river drains according to the tide time, and the pump stations were fully draining.
On the early morning of the 10th, “Lekima” landed, and the impact of typhoon gradually increased in the city, and the rainfall increased rapidly. "In more than 20 hours from the 9th to the 10th morning, 440mm of rainfall poured into the Baixi Reservoir area, and the water level of the reservoir rose by 6.58 meters," said the person in charge of Baixi Reservoir Management Station.
From the 9th to the 10th morning, the rainfall in the reservoir area of Hengshan Reservoir was 350 mm, and the rainfall in the reservoir area of Zhougongzhai Reservoir was 324 mm... "Before the typhoon came, the reservoir pre-discharged 90 million cubic meters, and the storage capacity of the vacant land was close to 3 Dongqian Lakes. With so large amount of rainfall in a short period of time, if there is no vacant storage capacity, the pressure on the downstream and urban areas will be even greater.” The relevant person in charge of the Municipal Water Conservancy Bureau said.
The major river network is just like the reservoirs. At 8 o'clock on the 7th, the water level of the main river network in the city was at a medium-high water level. After pre-discharging, it was reduced to a medium-low water level on the 8th. Overnight, the river surged, and by 7:00 on the 10th, the water level of each major river network was once again at a high level. "After entering the typhoon-affected period, the reservoir will be changed from pre-discharge to flood-breaking, and pumping stations and gates will speed up drainage." The relevant person in charge of the Municipal Water Conservancy Bureau said that after the typhoon affected the city, rapid runoff was formed in the upper reaches of the reservoir. The large reservoirs will be fully blocked to ensure the safety of the downstream. From noon on the 9th to 11:00 on the 10th, the city's 32 large and medium-sized reservoirs blocked 260 million cubic meters, equivalent to the water volume of two Baixi reservoirs.
Due to the rain and the downstream tidal water, the water level of the main stream of the Yaojiang River and the inland river exceeds the guaranteed water level. On the basis of giving full play to the tidal drainage effect of the Yaojiang sluice and the straight sluice along Yaojiang River, the water conservancy department made all efforts to reduce the inland water level through sluice gates and pumping stations, and all localities are also fully equipped to tide the drainage and do their utmost to reduce the loss of upstream flood.
"The battle is not over yet, and the storage and forced discharge cannot stop for a moment. From the current situation, the reservoir, river network and sluice pump have exerted huge disaster reduction benefits under the scientific dispatch of the anti-disaster and water conservancy departments at all levels. They have become an important basis to overcome floods and safeguard the safety of people's lives and property." The relevant person in charge of the Municipal Water Conservancy Bureau said, "We are continuing to have a better control of over-limit water level reservoirs and main streams and river networks according to actual conditions to ensure safety."