The grant to help clean up the San Gabriel Mountains National Monument is big news for a river that is key to the water supply.
The San Gabriel Mountains are 70% of the open space in Los Angeles County. The area, which is almost half a million acres, is designated as a national monument.
"We're acknowledging the importance need to continue to protect water quality while also expanding access here in the San Gabriel Mountains," said Joaquin Esquivel, chair of the state water board.
The stretch is used primarily for recreation. In 2021, more than 4.5 million people visited the area.
With an increase in visitors, it also brought an increase in problems.
Trash is a big issue. Now the state and the federal government are sending $3.5 million to help with maintenance and cleanup.
"The San Gabriel Mountains National Monument expansion also protects critical wildlife habitat, migration corridors, safeguards clean water and supports local economies," said Brenda Mallory, chair of the White House Council on Environmental Quality.
A major part of the funding is to improve the quality of a key source of water for Southern California - the headwaters of the San Gabriel River.
The watershed provides Los Angeles County with one-third of its water supply.
"It provides valuable habitat for wildlife, for aquatic life. For drinking water, yes, it's a source of drinking water," Jenny Newman of the Los Angeles Water Board said.
Construction on the first phase of the project will include an access trail along the river and restoration of plants. That's set for January.