How an ‘ancient landslide’ keeps threatening a railroad, homes in San Clemente
In 1968, San Clemente’s historic San Julian River flooded as a result of a landslide near the river’s mouth. The next year, authorities determined that the landslide was caused by a landslide of rock that had been dumped along the shoreline at the mouth of the river, according to an incident report from August 1968, San Clemente Public Library. The report also stated that the landslide occurred at 5:30 that morning with the storm tide already at its peak. During the subsequent week, the river remained low until it receded to its prior levels in the weeks following.
In the early 1970s, officials at the San Clemente Municipal Water District (SCMWD) began receiving reports about increased water use at the mouth of the river, due to an influx of debris from the 1968 landslide, according to the San Clemente Public Library. Over the next 14 years, the floodwaters receded, but the problem with debris continued to increase, the library said. In 1991, the SCMWD began to suspect that the debris had formed a dam on the river’s mouth, but officials did not realize the importance of this discovery until the mid-1990s, when residents of San Clemente began to complain about the amount of debris left behind after the flood.
In 1999, the SCMWD began installing a new intake and discharge structure that aimed to keep debris out of the San Julian River, the library said. However, the river’s flow rate did not change.
On March 17, 2017, the San Clemente City Council heard from officials of the San Clemente Municipal Water District (SCMWD) about the debris that was blocking the San Julian River. After being cleared, the debris that was left behind did not return, according to the San Clemente Public Library (SCPL). The SCMWD issued an emergency order for the removal of the debris that was blocking the San Julian River on April 12, 2017, according to