A few days ago, it was affected by heavy rainfall
The water level of the Qijiang River, a tributary of the south bank of the upper reaches of the Yangtze River, continues to rise
July 4
The "Qijiang River Flood No. 1 of 2023" was formed
This was released by Chongqing this year
The first small and medium-sized river numbered flood
Floodwaters pass through Chongqing's Qijiang urban area Photo from China News Network
What is a numbered flood?
Why are floods numbered?
What are the criteria for flood numbers?
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What is a numbered flood
April 2019
The Ministry of Water Resources issued the latest revision
The Regulations on the Numbering of Floods of Major Rivers in the Country are clear
The country's large rivers, lakes and inter-provincial flows into the sea
The water level (flow) of the main rivers is reached
Flood control warning water level (flow): once in 2 years ~ once in 5 years, flood magnitude
or water level (flow) that affects local flood safety
as a flood numbering standard
Why number the flood
For the public
Numbering floods can alert everyone
Which rivers are currently in the process of flooding
to enhance public awareness of flood risk prevention
For the flood control department
There is a numbered flood
It means that the water level at the key station of the river is reached
Alert water level or other specific value
There is a possibility that a dangerous situation may occur in the embankment
It is necessary to strengthen the inspection of dikes
Do a good job of flood prevention
How to number a flood
The flood number is by
River (lake) name
+
The year in which the flood occurred
+
Flood serial number
Composed of three parts sequentially
The inflow of the Three Gorges Reservoir reached 50,000 cubic meters per second, ushering in the No. 1 flood of the Yangtze River in 2020 Photo by Zheng Jiayu
For example, July 2, 2020 at 10 o'clock
The inflow of the Three Gorges Reservoir reached 50,000 cubic meters per second
The flood is the first time the Yangtze River has reached it in 2020
Numbered standard floods
It is numbered as "Yangtze River Flood No. 1 of 2020"
What is the numbering standard for large rivers and lakes
In accordance with the Regulations on the Numbering of Major Rivers in the Country
Different big rivers and big lakes correspond
Flood numbering standards are different
Take the Yangtze River and Yellow River flood numbers as an example
The Yangtze River number range is
The section from the main stream of the Yangtze River to the Datong River
When the flood of the Yangtze River meets one of the following conditions
Carry out flood numbering
01
The flow rate of the upstream Cuntan hydrological station or the inflow of the Three Gorges Reservoir reaches 50,000 cubic meters per second
02
The water level of the middle reaches the warning water level (32.50 meters, freezing the elevation of Wusong) or the water level of the Hankou Hydrological Station reaches the warning level (27.30 meters, freezing the elevation of Wusong)
03
The water level of the downstream Jiujiang hydrological station reached the warning level (20.00 meters, freezing the Wusong elevation) or the water level of the Datong hydrological station reached the warning water level (14.40 meters, freezing the Wusong elevation)
Once there is a compound flood in the Yangtze River
(Refers to the rarer phenomenon of flood "superposition")
When the flood reaches the numbering standard again
And when the interval reaches 48 hours
Numbered separately
The Yellow River number range is
The main stream of the Yellow River from Tangnaihai to Huayuankou River
When the Yellow River floods one of the following conditions
Carry out flood numbering
01
The upstream Tangnaihai hydrological station or Lanzhou hydrological station has a flow rate of 2500 cubic meters per second
02
The flow rate of the midstream Longmen hydrological station or Tongguan hydrological station reaches 5,000 cubic meters per second
03
The downstream Huayuankou hydrological station has a flow rate of 4,000 cubic meters per second
For compound flooding
When the flood reaches the numbering standard again
And the upstream flood interval reaches 48 hours
or when the midstream and downstream flood interval reaches 24 hours
Numbered separately
furthermore
Regulations on the Numbering of Floods in Major Rivers in the Country
For the Huaihe River, Haihe River, Pearl River, Songliao, Taihu Lake and other river basins
The flood number is also clearly specified
What is the flood numbering standard for small and medium-sized rivers
All localities refer to the Regulations on the Numbering of Major Rivers in the Country
Different small and medium-sized rivers were introduced
Flood numbering standard
Take Chongqing as an example
July 2021
Chongqing Municipal Water Conservancy Bureau compiled and issued
Regulations on Flood Numbering of Major Rivers in Chongqing
Clear use of warning water level (flow rate)
The flow rate in and out of the reservoir is used as the flood numbering standard
Mainly applicable in Chongqing
Qijiang, Longhe, Sexi River, Renhe River
The main stream of 7 major rivers: Meijiang, Daning and Binan Rivers
The water level in Qijiang District rises Image from China News Network
Take the Qijiang River, the first small and medium-sized river flood this year, for example
When the Qijiang flood meets one of the following conditions
Carry out flood numbering
01
The water level of Dongxi Hydrological Station reached the warning level (283.59 meters)
02
The water level of Gunan Hydrological Station reached the warning level (221.30 meters)
03
The water level of Wucha Hydrological Station reached the warning level (198.51 meters)
current
The whole country is about to enter a critical period of "seven lower and eight upper" flood control
The number of numbered floods will also increase
Let's focus more on flood knowledge
Enhance flood prevention awareness
Review丨Chen Rui
Executive producer丨 Fan Yizi
Responsible editor丨Yang Jing
Proofreader丨Meng Jing