The Carmel River Notch

 

The Carmel River Notch was first put in after the 1995 flood.  The notch is at a section of the river where the bed narrows. It allows for water to spill through the levy and into a flood plain.

From KSBW

Carmel River Flood 1998

The lower Carmel River has overflowed its banks numerous times throughout history causing extensive flooding of businesses and homes. For example, storms in 1995, 1997 and 1998 caused millions of dollars in flood damage to the mouth of Carmel Valley, and in 1995 destroyed the State Highway One Bridge at the Carmel River, causing a closure of the highway at that location for six months and cutting off access to and from Big Sur.

From: Big Sur Land Trust