Waimanalo residents are being asked to show up at a community meeting tonight to voice support or opposition for athletic fields and other planned improvements at the 75-acre Waimanalo Bay Beach Park, also known as Sherwood Forest.

The community group Na Kua‘aina o Waimanalo is sponsoring the meeting, which starts at 5 p.m. at the Waimanalo Public and School Library. Councilman Ikaika Anderson, who represents the district and has helped shepherd the Waimanalo Bay Beach Park Master Plan for more than a dec­ade, is scheduled to speak at 6 p.m.

The city began work on the $1.43 million first phase of the project about two weeks ago. It consists of grading and installing irrigation for a multipurpose sports field, a parking lot and a play apparatus, said city Parks and Recreation spokesman Nathan Serota.

Opponents of the plan said they were surprised to learn that trees were being leveled and brush removed from the site about two weeks ago. They are worried the improvements will eliminate green space and bring more outsiders into Waimanalo when it’s already being overrun by visitors who cause traffic congestion.

But Anderson and others who support the improvements said there is dire need for more athletic fields in Waimanalo, and the need will grow as more homes are built in the area.

Waimanalo resident Jody Green has collected more than 125 signatures on a petition asking the city stop the project.

Green said when work on the master plan began more than 10 years ago, she supported it because city officials promised it would use recycled water. She also liked that it would bring more walking trails, restrooms and camping sites. But the first phase consists only of a ball field, “which is the worst part of the plan,” she said.

“Waimanalo has changed so much since the inception of this plan,” Green said. “On the weekends, when it’s worse, traffic on the Kailua end backs up to Castle Hospital on the Kailua side and Sandy Beach on the Hawaii Kai side.”

Kukana Kama-Toth, a member of the community group Na Kua‘aina o Wai­manalo and the Waimanalo Neighborhood Board, said the board was informed that the project was commencing less than two weeks before it began.

Like Green, Kama-Toth said Waimanalo residents today “are facing other stresses upon our community than we were when the master plan was formulated.”

The master plan would largely benefit people from outside of Waimanalo when existing facilities are being neglected, Kama-Toth said. She cited the poor conditions of the Waimanalo gymnasium and Waimanalo Beach Park pavilion as examples.

Anderson said the public had been invited to participate and provide input on the master plan community working group, which had about a dozen people at any one time. Respected kupuna Rose Lani approached him in 2008, when he was an aide to the late Councilwoman Barbara Marshall, about the need for new athletic fields, restrooms and parking. The neighborhood board was supportive of the idea, and work on the master plan began, he said. The community working group added a larger group camping area, the possibility of cabins and playground apparatus, he said.

While he supported funding for the project, he purposely stayed away from the working group’s meetings. “I did not want people coming away feeling ‘this was Ikaika’s plan,’” he said. “This is the community’s plan.”

Anderson said a traffic impact analysis report concluded the overall project would not require any traffic signals fronting the park.

Critics are calling for improvements to be made to an existing field at Wai­manalo District Park that is seldom used. But both Serota and Anderson said the field is beyond repair because it sits on claylike soil.

Waimanalo Neighborhood Board Chairman Wilson “Kekoa” Ho said he believes the master plan has “overwhelming support” from a majority of the community.

“This is something so necessary,” Ho said. “This project is for the children. We don’t have enough playgrounds.”