Water is discharged from Gunnam Dam in the northern county of Yeoncheon, Monday. Yonhap

Torrential rains on Monday caused the water level of the Imjin River near the border with North Korea to rise dangerously, local officials said.

The northern parts of Gyeonggi Province were hit by rains ranging from 80 millimeters to 170 mm from midnight to 1 p.m., prompting weather authorities to issue heavy rain alerts for the areas.

The water level at Pilseung Bridge over the northern part of the river rose from 1.24 meters at 7 a.m. to 2 meters at 10:50 a.m. and 4.23 meters at 2:30 p.m., Yeoncheon County said.

The bridge is located near the Southern Limit Line, the southern boundary of the Demilitarized Zone, which separates the two Koreas.

When the level reaches 2 meters, an evacuation order is issued for riverside areas.

The water level in Gunnam Dam, located about 10 kilometers downstream from the bridge, also went up from 25.21 meters at 7 a.m. to 26 meters at 10:50 a.m. and 28.59 meters at 2:30 pm.

All floodgates of the dam were opened, discharging 2,306 tons of water per second. (Yonhap)