With the state now its official owner, the 3,716-acre property known as Moanalua Valley — considered a sanctuary for endangered and rare birds and plants — is permanently protected, officials involved said.

It's a far cry from what appeared to be the valley's fate more than 30 years ago, when state and federal officials planned to send H-3 Freeway through it.

"People have been trying to get their claws on the Moanalua Valley and the gardens for years and years and years," said Anna Derby Blackwell, retired first executive director of the Moanalua Gardens Foundation.

"It is my hope the state will do right by it, because it's a treasure," said Blackwell, who was among the individuals heavily involved in fighting the H-3 route through the valley. "It is in no way a totally pristine place, but there are places along the foot trail where you can see what Hawai'i looked like before people started messing it up."

The Trust for Public Land and the state this month announced the purchase of the valley from the Estate of Samuel Mills Damon, calling it the "permanent protection of one of the last truly open spaces in the urban Ho-nolulu area." The Trust for Public Land facilitated the $5.5 million purchase, which included $3 million from the state, $1.6 million from the U.S. Fish and Wildlife Service, and $900,000 from the Army.

In addition to the H-3, the valley also had faced the threat of residential development for two decades, the Trust said.

But clearly H-3 Freeway was the biggest threat. Two Damon heirs formed the Moanalua Gardens Foundation in 1970 to educate the community about Kamana Nui Valley in Moanalua in hopes of convincing people that the freeway shouldn't go through it. There were legal fights and protests by environmental, cultural and other community groups.

The foundation and H-3 opponents used a rock bearing ancient Hawaiian petroglyphs to get the valley entered into the National Register of Historic Places.

The U.S. Supreme Court in 1976 upheld an appeals court's injunction against H-3. The appeals court said that the secretary of transportation erred in not issuing a statement that there was no "feasible and prudent" alternative route for the freeway.

In 1977, the state moved the route to North Halawa Valley.

Moanalua is a key example "of places where people cared enough and they didn't go away," said Muriel Seto, who was an active supporter of protecting Moanalua. "The public won at Moanalua."

Seto, former executive director of the environmental group Hawaii's Thousand Friends, said she was happy to hear about the acquisition of the valley.

"I am thrilled about it because it's the crown on top," she said. "It finalizes it for Moanalua."

Kamana Nui and Kamana Iki valleys are known collectively as Moanalua Valley. In the 1600s, the ahupua'a of Moanalua — including the valley — was designated the center of hula and chanting by O'ahu's King Kakuhihewa.

It is believed that Kamehameha the Great rested in Moanalua following the major battles of Nu'uanu and Kahauiki during his conquest of O'ahu. The land was passed on several times, including to Prince Lot — who reigned as King Kamehameha V from 1863 to 1872. It also was owned by Princess Bernice Pauahi Bishop, who willed the land to her husband's business partner, Samuel M. Damon, when she died in 1884.

The valley has five distinct forest types and more than nine miles of streams, the Trust for Public Land said. It's considered among the main habitats for the endangered 'elepaio bird. According to the U.S. Fish and Wildlife Service, it was the last place where the rare O'ahu creeper and the endangered Hawaiian hoary bat were sighted. It also has several cultural sites, including a pohaku carved with unique petroglyphs, the Moanalua Gardens Foundation said.

The valley will be managed by the state Department of Land and Natural Resources' Division of Forestry and Wildlife and will be added to the Honolulu Watershed Forest Reserve. That will enable the state to carry out watershed protection and research, native species habitat restoration, endangered species recovery, forest restoration and other conservation activity, DLNR said.

Blackwell said she was relieved to know that the land didn't ultimately wind up in the hands of developers. But she expressed some concern about DLNR's ability to manage the valley because there's "so much on their plate."

The valley will eventually be open to the public for hiking, hunting, cultural resource preservation and education. The state also will manage the back of the valley for wildlife preservation.

It will likely take four to six months before the state will open the valley to the public for hikes, DLNR said. The agency said it needs to first complete an administrative process — which includes a public hearing — to officially designate the area a forest reserve.

Still, publicity about the sale appears to have sparked a renewed interest in the valley in recent months, spurring an increase in hikers and inquiries about the area, said officials at the Moanalua Gardens Foundation, which has been leading school and other tours through the valley for more than three decades. Those tours are on hold until DLNR completes steps for forest reserve designation.

Mahealani Merryman, executive director of the Moanalua Gardens Foundation, is cautiously optimistic about the land transfer. "I want to see what's going to happen," Merryman said. "I'm hoping that the state will care for this and continue to allow access."

Steven Onoue, president of the Moanalua Valley Community Association, said he's very pleased that the state acquired the land, and that he has noticed more hikers recently.

"I think it's a good thing that people are enjoying it," he said. "Our only concern is that they do respect the land."

Reach Lynda Arakawa at larakawa@honoluluadvertiser.com.