Expect some churn in the state Senate, with a couple of incumbents leaving to pursue higher office. Of the Senate’s 25 seats, 13 are up for election this year — and of these, only one incumbent, Breene Harimoto (District 16, Pearl City), is running unopposed for another four-year term.

On Oahu, six Senate seats have contested races in the primary election; here are the Star-Advertiser’s endorsements for them.

>> District 12 (Kakaako-Waikiki): Democrat incumbent Brickwood Galuteria faces a strong challenge from community advocate Sharon Moriwaki. A prominent entertainer and former Hawaii Democratic Party chairman, Galuteria is capable and an amiable ambassador of aloha, involved in Native Hawaiian and kupuna issues. But Moriwaki gets our endorsement here, for her breadth of experience and robust engagement in her neighborhood’s rapid growth, providing a needed proactive voice as development advances. Founder/president of Kakaako United, Moriwaki also knows government as one-time deputy director of the state Labor Department and director of Human Resources; and has served in Hawaii’s Judiciary as administrative director of the courts. She’s also co-chaired the Hawaii Energy Policy Forum, which would serve the Legislature well as fuel issues intensify.

The winner here will face Republican Lynn Mariano.

>> District 18 (Mililani-Waikele-Kunia): Michelle Kidani, the Democratic incumbent, has no challenger in the primary so awaits the winner of the Republican race: either Emil Svrcina or Anthony Solis. Of the two, Svrcina gets the nod by default as Solis has been unresponsive on the issues. Svrcina is a state-employed computer specalist and programmer critical of overtaxation and over-reliance on big government, and vows to fight against Hawaii’s “rigged housing market.”

>> District 19 (Ewa Beach-Iroquois Point): This race is technically a special election to fill the last two years of the office being vacated by Will Espero, now running for lieutenant governor.

Three solid Democrats are vying here: Veronica Duzon, a lawyer and community organizer; Matt LoPresti, currently a state House member and Asian-Pacific Studies professor; and Alicia Maluafiti, a political lobbyist and founder of Poi Dogs & Popoki, a spay-and-neuter organization. As expected in this booming district, traffic and schools overcrowding are top issues — and both LoPresti and Maluafiti, in particular, are well-versed in examining options. LoPresti, though, in his four years in the state House has shown the ability to deliver for his constituency, whether it be funds for Campbell High School’s addition or Fort Weaver Road improvements, so he gets the nod.

The winner faces Republican Kurt Fevella in the general.

>> District 21 (Kalaeloa- Waianae-Makaha): Democratic incumbent Maile Shimabukuro faces Timothy Riley, a retired Georgia assistant county commissioner who’s also worked as a rehabilitation and child counselor. He advocates tackling housing and cost-of- living problems by raising the minimum wage and fixing the Jones Act. Shimabukuro has been adept at advocating for the district and delivering results, such as for Nanakuli traffic projects and funds to expand area schools’ programs and building. A lawyer for a legal services nonprofit, and as Hawaiian Affairs Committee chairwoman, she knows her consti- tuents’ needs, from transitional shelter to Section 8 housing. She’s earned another term.

The winner here will face Republican Diamond Garcia.

>> District 23 (Heeia-Laie-Waialua): It’s a winner-take-all contest between two seasoned politicians: incumbent Gil Riviere and former legislator Clayton Hee. Both Democrats share an understanding to “keep the country country” and to be vigilant against urban sprawl. But Riviere has proven himself to be a conscientious and committed lawmaker, attuned to the needs of his district, so there’s no need to make a switch. Further, where Hee has a polarizing political history, Riviere has connected with his more-collaborative ways, staking out mitigations against tourism impacts on natural resources and on rental inventory.

>> District 24 (Kailua-Kaneohe): Jill Tokuda is leaving this office to run for lieutenant governor, so here’s another intriguing winner-take-all contest. The four-year term will go to either Kenneth Ito or Jarrett Keohokalole, now colleagues in the state House. It’s a study in contrasts: Ito, 74, has served in the Legislature since 1994, with military and educational backgrounds among his strengths; Keohokalole, 35 next month, is a relatively new politico, elected in 2014. Both have strong constituencies — but Keohokalole is living the many challenges facing today’s young working families.

As House majority policy leader this past year, he helped move laws to alleviate Kahekili Highway traffic, address Kaneohe Bay pollution, and take steps against housing and homelessness. He’s started to build a solid legislative record and shows potential for more, so gets our nod.

TOMORROW: Contested primary races in state House Districts 20-33.