The Basic Situation of Songhua River Basin Hydrological Station Network in 1998

From June 1998 to August, frequent rainfall such as heavy rain occured in the Nenjiang River Basin resulting in Nenjiang and its right had produced great floods in succession. 100 to 500-year return period flood happened in Qiqihar Station, Jiangqiao Town and Dalai Station which were in trunk stream of Nenjiang River. 50-year return period great flood occured in Daiji Station and Harbin Station which were in trunk stream of the Songhua River. The height of the flood peak was large and the duration of the flood was long, which was the greatest of history.

There were 731 various hydrometric stations in the Songhua River basin (see chart four), including 185 hydrologic stations, 32 water stations and 514 rainfall stations. The network density of the rainfall station was 766km²/ station and the density of the flow station network was 3010km²/ station. There were 164 hydrological stations in Nenjiang River basin. The density of rainfall station network was 1811km²/ station and the density of flow station network was 5211ktn²/ station. Second, there were 170 stations in the Songhua River basin. The density of the rainfall station network was 432km²/ station and the density of the flow station network was 1596km²/ station. There are 397 various hydrological stations in the main stream basin of Songhua River. The density of rainfall station network was 470km²/ station and the density of flow station network was 2273kmV station. From the distribution of hydrological station network in Songhua River basin, Hydrological station network distribution was basically reasonable in Di’er Songhua River and the main stream basin of Songhua River. However, the distribution density of hydropower station could basically control rainfalls. The number of hydrological stations in the Nenjiang basin was obviously small. The second tributaries and third tributaries were also lack of flow stations. The rainfall station was 1811km2/ station. For existing station network, it was difficult to obtain more complete and accurate precipitation event in Nenjiang basin.