The second Songhua River and the main tributary Lalin River, Ashi River, Mayi River, Mudan River, Woken River, etc. of Songhua River all had heavy rainstorm in late August, especially the second Songhua River, Mudan River and Tumen River, where the rainfall about the rainstorm center of three days was 149.3mm, 187.3mm and 241.6mm respectively. The rainstorm not only caused flood or great flood to rivers above, but also met the floods in Nenjiang River in July. And there was a 1m3/s flood in Harbin, which was the eighth largest flood from 1898 to 1998. After the trunk stream flood met the flood in Mudan River in JiaMuSi, the peak flow rate reached 19000m3/s (after reduction), which was the third largest flood between 1898 and 1998.
Rainfall process
Songhua River basin has a lot of rain in May, the duration of rain exceeds 15 days, and the amount of rainfall is about 60-180mm, three times more than that in the past years. Intense rainstorm processes occurred between June and August, and there were four cases with wider range as follows:
During 18th to 20th June, rainstorm covered Lalin River, Mayi River and Ashi River basins. Total rainfall was around 80-150 millimeters. Mostly within 18th and 19th, centered in Lalin river inspect station, the rainfall was 186.7mm on 18th for this station.
During 6th to 9th July, rain to heavy rain in the middle and lower reaches of Nenjiang. The rainfall was around 100-200mm. Mostly within 6th , centered in the downstream of Yalu River and Chuoer River basins, the rainfall was above 110mm every day.
During 5th to 7th August, the rain to heavy rain covered Latin River, Maui River, Mudan River areas and the wetland in the north of Songhua River, Tangwang River and the upstream area of Hulan River. The rainfall was about 100-260mm. Heavy rainstorm within the 6th, centered in Latin River area. The largest rainfall of Dexing Station is 183.5mm.
From 21st to 23rd in August, the rain to the heavy rain covered Mudan River, Mayi River, Woken River, the second Songhua River area, the downstream of main stream and Tumen River. The rainfall was 100-150mm, mostly within 23th. The rainfall in Mudan River area usually was 100-130mm, which the center was in Jingpo Lake Station and the rainfall was 138.8mm per day. The heaviest rainfall in Mayi River Lianhua Station was 118.5mm, the Woken River Woken Station was 126.3mm, and the rainstorm center in Tumen River at Jinkuang Gou was 181.5mm. The intensity of rainstorm and the scope of the rainstorm were rare in history.
In 1960, the Songhua River basin not only had a lot of rain, but also a wide range.
The rainfalls in Lalin River, Ashi River and Mayi River in the south of HeiLongjiang Province were a little much in June, where the rainfalls were 100-250mm per month, the 1-2.5 times than the same season of many past years' average number. The rainstorm center at Llin River basin Caijiagou Station was 313.0mm per month, which was the three times than the same season of many past years' average number. The rainstorm center at middle and lower reaches Yalu River and Chuoer River areas was 339.0mm measured by Jingxing Station, which was 2.5 times than the average number in many years. The monthly rainfall above 200mm covered 70,000km2area.
In August, the rainfall in the east and south of Heilongjiang Province was 250-300mm, which was 2.5 times than the average number in many years. The center at Changjiangtun Station was 359.2mm per month, which was 2.7 times than the average number in many years. The monthly rainfall above 200mm covered 150,000km2areas, while above 250mm covered 80,000km2.
The measure of area in Lalin River, Mayi River and Mudan River basins'monthly rainfall above 300mm was 30,000km2.
The two rainfall processes on August 5th to 7th and 22nd to 23rd covered 300,000 km2 in Songhua River basin. The latter rainstorm above 100mm was 50,000 square kilometers, which covered the upper reach of FengMan in the second Songhua River area, Mudan River area and the tributary Gaya River of Tumen River. The rainfall above 50mm per day was 100,000 km2.
The information is provided by Disaster Risk Reduction Knowledge Service.
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