The Merced County Sheriff's Office says the person was found dead in the Merced River.
The search began late Sunday afternoon near the Hatfield State Recreation Area, about eight miles west of Stevinson.
The sheriff's dive team was called out to help with the search, and eventually found the body Sunday night.
Deputies said a man met his friends who were fishing on Sunday.
They decided to cross this part of the Merced River at the Hatfield State Recreation Area, when the man suddenly dropped 10 to 15 feet underwater.
"The friends noticed that their partner was in distress. They went in the water to try and save him, putting their life in danger as well, but they weren't able to grab him in time," said Sergeant Larry Hudec.
The sheriff's dive team pulled the man from the water within 11 minutes of arriving at the scene.
Sadly, it was too late.
"It's still continues to be a problem, but we just wanna try to resolve that as much as possible," said Deputy Michael Domingue.
The department has been using drone footage to help analyze the Merced River.
"The river is a rocky bottom, used to be a slough area, where they mine gold and it's just all rocks. With all the vegetation surrounding that, there's a lot of down trees, sinkholes," said Domingue.
The next step will be sharing additional information with the community about the most dangerous areas, and what to expect if you enter the water.
"Currently, the sheriff's office is looking for ways to kind of help people understand what they're getting into when they start to float in the river. So, we're looking at placing signage either on the river or before you enter the river," said Domingue.
He said that signage may include water flow rates and how long it will take to float down to Henderson Park in Snelling, which has been continued to be a problem spot.
"We tend to have a lot of rescues, the river does split, so we may have signage directing the best way to stay because if you go other direction, you may end up trees and end up in position to get out raft and walk and get out and injured in a brush area and not know where you are," said Domingue.
The sheriff said the signs will go up as soon as they're printed.
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