Demystifying Big Data Tracking Flood More than 4,000 hydrological telemetering stations in Sichuan are moved by the ＂peak＂
From July 9 to 11, in just three days, the string of Sichuan flood control emergency was tightened again and again. At 7: 00 am on the 11th, Sichuan Flood Control and Drought Relief Headquarters connected Sichuan Hydrology and Water Resources Survey Bureau and several local anti-finger offices through video conference to forecast and dispatch the emergency flood along the river to meet the flood peak. How to schedule? Upstream water, how to store water and flood discharge in the reservoir? How to reduce the impact of flood peak transit on coastal cities? ….. To find out the "details" of the flood, we need to rely on hydrological monitoring and water regime forecasting.
In this hydrological information network covering the whole province, the "big data" sent back in real time from hydrological telemetering stations in various river basins provide decision support for flood control and disaster reduction, and make an important staff for the safety of the land of abundance, ranging from analyzing and judging the impact of the flood process to the height of sandbags on the flood front.
monitor
More than 4,000 telemetering stations in the province transmit hydrological data 24 hours a day.
July 12, Chengdu, Yin. In the hydrological duty room of the Provincial Hydrological Bureau, on the hydrological monitoring platform, the minute-by-minute changes of rainfall, water level and flow of major rivers in Sichuan Province are clearly displayed.
In this extraordinary period, the main work of the Provincial Hydrological Bureau is to judge and predict the fluctuation of river water level in the future through data, and to predict whether the flood has exceeded the warning or guaranteed water level. "For example, take the forecast of san huang Temple Station in Jintang County as an example. At 17: 00 on July 11, the peak flow rate was 8,000 cubic meters per second, and the actual peak flow rate was 7,810 cubic meters per second, which exceeded the guaranteed water level by 2.64 meters." Chang Gaosong, a senior engineer in the Hydrological Forecasting Department, said, "When it rains, the hourly rainfall analysis is a necessary work link for forecasters. According to the change of rain conditions, they made and released the flood forecast of the corresponding rivers in the rain area. After the flood process ended, they also analyzed and summarized the characteristics of rainstorm and flood. "
More than 4,000 hydrological, water level and rainfall telemetering stations scattered around the province transmit hydrological data to the provincial hydrological forecasting center 24 hours a day. They are called "clairvoyant eyes and ears with the wind" for flood control and disaster reduction by people in the industry. The sensors deployed have no dead ends to monitor rainfall or water level changes, and the farthest monitoring "guard" sticks to shiqu county, Ganzi Prefecture.
"The collected information is transmitted to the Provincial Hydrological Bureau and the River Basin Bureau through SMS, 4G network, Beidou satellite and other communication methods." Zhao Guomao, the person in charge of the hydrological forecasting center, said that the hydrological forecasting departments in various places will also report the rain, hydrological conditions and forecast information to the local anti-finger department in time, and transmit them to the hydrological forecasting department of the Provincial Hydrological Bureau. "After we receive it, we will discuss it in time and report the analysis results to the provincial flood control headquarters."
predict
In March this year, it was predicted that there would be a serious flood in Longmen Mountain area this summer.
Prevention is better than disaster relief. Real-time rolling update and collection of local data, with 24-hour flood prediction.
"In the past, after the rain, it was expected that the river water level would reach the warning water level, so we made flood forecast. But now, as long as there is a blue rainstorm warning and above, we must make flood forecast ahead of time according to the weather forecast." Zhao Guomao introduced that every day at 7: 00 a.m. or 4: 00 p.m., the Provincial Meteorological Bureau will send a weather forecast to the Provincial Hydrological Bureau, and an "alarm" will be sounded from time to time.
At 16: 00 on July 10th, the hydrological forecasting center received a yellow rainstorm warning, and the former analyzed the river situation in the rainstorm coverage area according to this information: whether it will exceed the alarm and guarantee, and the fluctuation of flow and water level … one by one, the questions were put on the discussion table. "Although the trend forecast is not very accurate, it can at least allow the flood control department to make preventive deployment in advance." Zhao Guomao said.
Through rainfall analysis, we can roughly judge the change of river water level in the region. "The rainfall in a basin will eventually converge into the river, and the hydrological station at the outlet of our river can monitor the water quantity of the whole basin." Zhao Guomao said that they will work out a flood forecasting plan based on the measured rainfall or water level and flow data collected by the station for many years. "But the situation in nature is very complicated, and even the same rainfall will have different water conditions." Therefore, they will analyze the water level and flow of the river after the rainfall according to the forecast scheme.
The pre-judgment of the overall flood situation in that year may begin three or four months before the flood season. "In March this year, we analyzed the factors that will affect the climate in Sichuan according to the precipitation law over the years and the climate change this year, such as SST, subtropical high and monsoon." Ju Yumei, a senior engineer of the Provincial Hydrology Bureau, said that it was predicted at that time that there would be a serious flood in the Longmenshan area during the flood season this year.
dispatch
Dispatch the flood of Mianyang Jiangyou City beyond 100 years into the flood of once every 10 years.
To cope with the flood, dispatching the upstream reservoir is a measure to cut off the peak and store the flood, so as to avoid the danger caused by the excessive inflow from the downstream. The storage and discharge of reservoirs, in addition to the storage capacity of reservoirs, the water storage situation of incoming water and hydrological forecast are also the basis for their judgment and control.
Since July 9, Sichuan Province has also dispatched some large reservoirs in the upper reaches of the province, such as Zipingpu, to make room for the flow to be put into storage. "In advance of flood discharge, we will make scientific and reasonable dispatching suggestions by analyzing the predicted inflow and combining the rainfall data. The most important thing is to consider the flood control safety of the reservoir and the downstream."
Zhao Guomao said that when the flood peak arrives, the reservoir that makes room will also play the role of flood detention. According to the plan, some floods will be intercepted, and the amount of water entering the downstream will be adjusted to ensure the safety of the downstream. "Don’t underestimate the flood detention function. The total flood detention of only three reservoirs during this flood is equivalent to the storage capacity of 8.5 large-scale water conservancy projects."
"The whole dispatching has really played a great role. The incoming traffic is getting bigger and bigger, and the outgoing traffic is still in a stable state." Zhao Guomao, for example, said that the Zipingpu Reservoir in Minjiang River Basin timely dispatched and controlled the discharge, which gained valuable time for the rescue of Jinma River downstream. Wudu Reservoir in Fujiang River Basin pre-discharges ahead of schedule, and adjusts the flood with a return period of over 100 years in the main stream into a flood with a return period of 50 years; Tingzikou Reservoir in Jialing River Basin pre-discharges ahead of schedule and timely dispatches, and adjusts the flood with a return period of over 50 years in the main stream into a flood with a return period of 10 years. In addition, by pre-discharging the reservoir in advance, the once-in-100-year flood in Mianyang city is scheduled to be a once-in-50-year flood, and the once-in-100-year flood in Jiangyou city of Mianyang is scheduled to be a once-in-10-year flood. (Reporter Yang Chen, trainee reporter Yang Jinzhu)