Palo Alto Councilwoman Karen Holman prevailed Tuesday in an unusually expensive and competitive race for a seat on the Midpeninsula Regional Open Space District board against her longtime political adversary, Councilman Greg Scharff, early Election Day results indicated.

Early results showed Holman winning more than 60 percent of the votes in both Santa Clara and San Mateo counties. The two termed-out council members are vying to to represent Ward 5, which includes East Palo Alto and portions of Menlo Park, Palo Alto and Stanford.

The seat is now held by Nonette Hanko, a local resident who helped found the open space district in 1972. Hanko did not seek re-election.

In Santa Clara County, with 95 percent of the precincts reporting, Holman was leading with 67.8 6 percent of the vote to Scharff's 32.14 percent. In San Mateo County, with fewer than 2,000 votes counted, Holman had received 63.7 percent of the vote to Scharff's 36.3 percent, according to early results.

While races for the district are typically low-key affairs that rarely entail more than a few thousand dollars in expenditures, the Ward 5 race was a notable exception. Scharff had loaned his campaign more than $120,000 while Holman raised $28,271 in contributions as of Oct. 20.

In the run-up to Election Day, both candidates touted their environmentalist bona fides, with Holman citing her long history of advocating for conservation on the City Council and Scharff emphasizing his service on the Bay Conservation and Development Commission and on the San Francisco Bay Restoration Authority boards. Holman, who is aligned with the council’s slow-growth "residentialist" faction, had earned the endorsement of the entire open space board, including Hanko, who had personally encouraged Holman to run. Scharff, who is associated with the council’s more growth-friendly wing, was endorsed by prominent area Democrats, including state Senator Jerry Hill, state Assemblyman Marc Berman and San Mateo County Supervisor Dave Pine.

After her election was secured, Holman said she was "relieved" by the results and pointed to the support she had received from other board members.

"I really felt the burden of not wanting to disappoint them,"

She also said she saw her election as a victory for grass-roots campaigning and contrasted her campaign with that of her opponent.

"I’m gratified that the public recognizes the value of grass-roots campaigning, as compared to a heavily funded campaign," she said.

This story will be updated as more results are released.