Observing debris flows through normal flood water levels

The flood level should be judged based on debris flow investigation and hazard zoning, by understanding local weather forecast information and actually observing the water flow caused by heavy rain in the valley. Normal flood levels can be determined from vegetation growth or ant nest distribution. When the flash flood level is close to the normal flood level and heavy rains continue, personnel must be sent on-site to observe and take necessary avoidance measures. If the amount of earth and rocks entrained in the flood increases or intermittent flow breaks occur, be aware that debris flows may occur.

For valleys where debris flows often occur, the occurrence of debris flow disasters can be judged by the debris flow mud line. When the water level of flash floods and mudslides is close to the normal mud level and heavy rain continues, personnel evacuation measures must be taken.

Measurement of debris flow accumulation and mud level height (Xinping, Yunnan, 2005)

The residual mud level trace of the debris flow formed after the collapse of the Yigong landslide dam in Tibet in June 2000 (2006)< /p>