The creek is a crucial part of what made it appealing for the first settlers to start a life here and is the lifeline for plants and animals in the area. It's also the largest source of water in the San Ramon Creek watershed, which encompasses Danville and Alamo.
Yet it sometimes suffers from pollution.
"It's not unusual to find shopping carts in the creek, or bicycles," said Linda Ballentine, a Danville resident who works at the Contra Costa Resource Conservation District. "People just abandon them."
Unlike neighboring towns, there's no community group in the Danville area in charge of caring for the watershed and cleaning up the creek. Ballentine is hoping to change that - and she has a plan.
"Mainly wh at I'm trying to do is just raise awareness of proper creek stewardship," she said. "It doesn't take a lot to do."
First, what is a watershed?
A watershed is a geographical area that functions like a bathtub: It collects all the water that accumulates on the land.
The area is defined by ridges and mountains at its borders, or simply the subtle slope of the land that causes water to flow in a certain direction.
Rainwater flows into streams, which flow into creeks, then rivers and lakes, and eventually is funneled - similar to a tub's drain - into the sea.
About 72,000 people, including the populations of Danville and Alamo, live within the San Ramon Creek watershed, which is defined by Mount Diablo to the east and the Las Trampas Ridge to the west.
In the San Ramon Creek watershed, the water flows north, into the Suisun Bay. Sycamore, Green Valley and Bollinger creeks flow into San Ramon Creek, which flows into Walnut Creek and then to the Bay.
"We have to look out for the other communities that are downstream from us," said Ballentine. "That's part of our incentive for keeping our creeks clean."
Keeping the watershed healthy
People in the Danville area are environmentally conscious: They know not to litter and do their best to be mindful. But not everyone is fully aware of the damage toxins and trash can do to the creek, said Ballentine.
Did you know that soapsuds from washing your car outside can harm the watershed and the wildlife that lives in it? What about the runoff from lawn fertilizers? Not to mention plastic bags, soda bottles or even tree branches discarded on the banks of a stream.
"People might say, 'Oh, what can a little fertilizer do?' But fertilizer can cause algae to grow in the creek," Ballentine said. Algae make the water temperature rise, which throws off the oxygen content and makes the habitat unlivable.
On occasion salmon have been known to swim in the San Ramon Creek, especially during their spawning season in the fall.
"Whatever debris and materials are in the creek from the summertime and spring ... that's what the fish are encountering when they come up to spawn," said Ballentine.
While a polluted watershed can harm plants and animals, a healthy watershed will attract them. One reason vegetation is important is that it helps prevent erosion.
Without plants, "there's nothing that's going to hold that soil in place if you have a severe storm," Ballentine said. "The landslide material will fall into the creek."
An unhealthy watershed can also affect the people who live in the area. When debris builds up in the creek it can block pipes and drains, making the water level rise and eventually overflow, causing flooding.
The biggest risk of floods occurs if the first rain of the season is a major storm. During a downpour, debris will wash off people's properties into storm drains and into the water, potentially clogging pipes and raising the water level.
For all these reasons it's vital to get in and clean up the creek, which is just what Ballentine hopes to do.
Mobilizing the community
Creek cleanups are a great way to fix an already polluted watershed, but it's also important to prevent the environment from getting to that point in the first place.
Ballentine is hoping to inspire residents to feel a sense of ownership for their watershed, so they're motivated to care for it year round.
"We'd really like to get something going on here, just a network established," she said.
She has applied for grant funding to establish a watershed program for Danville, with herself as the coordinator and volunteer members. The group would hold creek cleanups and raise awareness about watershed health.
"It's fun to know about your environment and the habitat, and enjoy the birds and wildflowers and things like that," said the UC Berkeley wildlife management major, who went on to earn a master's in agribusiness finance.
"I was always interested in the crops and the environmental issues," she continued. "I was always wishing I could be the farmer."
A mother of two - a son at Montair Elementary and a daughter at Charlotte Wood Middle School - Ballentine also offered to go into classrooms to teach about watersheds.
She has been talking with town leaders and staff about establishing a watershed program in Danville.
"Both the mayor and the city manager have just been very 'rah-rah' about it," she said. "It's a positive thing. It's a community building thing."
Town Manager Joe Calabrigo said the town already does a lot to maintain clean water.
"Of course we're anxious to help out with something like this, but our maintenance crews, really, starting in the middle of next month, go out and do a lot of creek cleanup on their own," he said.
Every year, from August through early October, town staff will check to "make sure there's nothing in the creeks that will get washed downstream and cause obstructions once the winter rains come," he said.
To comply with regulations from the California Department of Fish and Game, creek cleanups must be completed by Oct. 15.
Calabrigo said there are plenty of people in town that would be willing to lend a helping hand, and "we certainly welcome the help, but it needs to be coordinated so we're making the best use of the volunteers."
"There's good community spirit," agreed Ballentine. "It's just a matter of getting everyone together."
Cleaning up the creek
Grab some coffee and a donut, gloves and a trash bag, and you're ready to hit the water.
Creek cleanups can be a lot of fun, said Ballentine. She has participated in events in neighboring towns and has seen more than 100 people show up. The largest existing local watershed group is called "Friends of the Creek." It holds annual cleanups in Walnut Creek.
For a Danville cleanup day, Ballentine envisions a booth at the Saturday farmers market where people can sign up even if they weren't already planning on participating.
Volunteers are given garbage bags and gloves and assigned to a specific stretch of the water.
"They just walk along the creek and if they find bottles or garbage, they put it in the bag," Ballentine said.
The full bags are left near the water's edge and picked up by another group of volunteers. Sometimes all the bags are brought to a single location where they can be counted, and everyone can see the difference they've made.
"It's a great activity for like a Cub Scout group or a school program," said Ballentine. Church groups, sports teams and families can enjoy working together for the good of the community.
If a watershed program is started in Danville, Ballentine said she'd like to call the group "Stewards of the San Ramon Creek watershed."
"You don't have to be a stakeholder to be a steward," she explained. "You just have to care."