松花江、嫩江流域黑土区是我国重要的商品粮基地。但是，由于近几十年的人为开发，导致植被严重破坏，水土流失触目惊心。’９８嫩江流域超强度、长历时的降雨，导致该地区各支流山洪暴发，嫩江、松花江干流防汛形势异常严峻。调查’９８洪灾的结果说明，异常降雨是天灾，... Songhua River and Nenjiang River Basin are the important commodity grain bases in our country. However, as a result of man-made development in recent decades, vegetation has been severely damaged and water and soil loss has been shocking. ’98 The super-strength and long-term rainfall in the Nenjiang River basin led to the outbreak of tributary flash floods in the area. The flood control situation in the Nenjiang and Songhuajiang rivers was exceptionally severe. The results of the survey ’98 flood show that abnormal rainfall is a natural disaster, ...