With master planning finally underway, Tolay Lake Regional Park, a sprawling patchwork of grasslands, oak woodlands and agricultural space, could open to the general public by early 2015, officials say.

Petalumans have eagerly awaited the expanded hiking, horseback riding and other recreational opportunities that will come with the park opening, something that was delayed for many years by a lack of money needed to create the master plan.

Tolay, located in the Sonoma Mountains two miles southeast of Petaluma, will be Sonoma County's biggest regional park at more than 3,400 acres when combined with the adjacent Tolay Creek Ranch property owned by the Sonoma Land Trust. Master planning got underway in late 2012 after the county received a $300,000 grant from the California Coastal Conservancy and a $500,000 donation from the Federated Indians of Graton Rancheria, the group that is developing the casino in Rohnert Park.

At the end of the two-year planning process, the park will begin opening in phases. The first phase will allow the general public to access the land for hiking, wildlife viewing and other activities that don't require much infrastructure.

Other phases could include retrofitting the property's old buildings, creating an interpretive center, and improving the dilapidated roads that lead to the park.

Park officials, in coordination with a contracted planning firm, are conducting an online survey to gather public input on what the park should ultimately offer, and on June 15, they held a worskhop at the park that drew more than 50 people.

The majority of those who have weighed in — 87 percent — say they want a serene environment for hiking and wildlife viewing, though people also expressed an interest in environmental and historical education, horseback riding, kayaking, dog walking, and camping.

"It will always be a trail park, with an open space feel, wide horizons, undeveloped," said Brandon Bredo, a ranger at the park.

But building trails won't be the only work involved in fully opening Tolay. The park is rich in natural, cultural and agricultural history that must be considered and preserved.

Its name comes from the 175-acre natural, seasonal lake at its center, the largest in the San Pablo Bay watershed. Fed by 18 nearby springs, it was once double its current size before settlers altered it for farming. Rare turtles live there, as well as dozens of species of birds, including golden eagles. For thousands of years, Native American tribes have considered Tolay Lake a spiritual destination.

"The shallow lake bed was a very sacred place, a gathering place for Indian doctors and medicine people from all over the area," said Greg Sarris, chairman of the Federated Indians of Graton Rancheria. Sarris said many members of the Graton Rancheria are descended from a Coast Miwok tribe that lived on the southern end of Tolay Lake.

Indians journeyed to the lake to toss in small rocks, charmstones, used in healing practices. Some of the stones found there originated as far away as the Mexican border.

Some of the charmstones now lie in the Smithsonian in Washington, D.C.

In the 1800s, settlers cultivated much of the land that is now Tolay for farming, and from the mid 1900s, the Portugese cattle farming family the Cardozas owned it.

They sold the land to the county in 2005 for $18 million. In 2007, the Tolay Creek Ranch parcel was acquired in a separate deal. Five houses, 10 ranch buildings, and cattle and goat herds remain on the property, a reminder of its agricultural history.

The park system is seeking to preserve all these elements as it develops Tolay, which is why planning will take two years.

The park is already open on weekends to about 3,000 people who hold a permit, earned by attending an hour-long orientation session. Permit holders can hike or horseback ride on the park's 9 miles of trail, which take them around Tolay Lake and beyond, to hills that rise up about 700 feet, offering views of Petaluma and San Pablo Bay. Creeks and oak woodlands provide a respite from the otherwise open grasslands.

Restoring the lake and the land surrounding it is a goal of the county as well as the Graton Rancheria, which has been actively participating in the planning.

"When you have an amazing resource like this, the opportunities to do all sorts of things are endless," said Parks Director Caryl Hart.

What ultimately happens at the park will depend on funding and approval by neighbors. Neighbors have expressed concerns about trespassing, vandalism and fire, said Bredo.

Currently, there is no money set aside to implement the plans for the park, but Hart said that funding often becomes available once the master plan is in place. The recently opened Taylor Mountain Regional Park, for instance, got a $750,000 grant after the master plan was complete.

Anyone wishing to weigh in on what the park should become can complete the online survey through July 15 at https://www.surveymonkey.com/s/TolayLake. The next workshop, at which three conceptual plans for the park will be presented, is expected to take place in the fall.

(Contact Jamie Hansen at jamie.hansen@arguscourier.com)