A plan to build a church on a site that serves as a stormwater basin in Mililani Mauka is drawing both support and opposition from residents, with some saying the proposed New Hope facility will enhance the neighborhood while others raise concerns about traffic and noise.

The 1.5-acre site along Lehiwa Drive, adjacent to residential neighborhoods and near Mililani Middle School, was purchased by New Hope Central Oahu from Castle & Cooke for $100 in April. The property is zoned residential, but a meeting facility is a permitted use, with a height limit of 25 feet. Church officials propose that the facility will feature about 50 parking stalls, a conference room, meeting rooms and other facilities.

The church applied for a conditional use permit in July with the city’s Department of Planning and Permitting. A public hearing on the project will be held at 10:30 a.m. Sept. 18 at the Mission Memorial Building.

New Hope Central Oahu Senior Pastor Mike Palompo said the facility would be a benefit to the community and convenient for the church’s nearly 300 Mililani members. He added that while the church held services at Mililani Ike Elementary for eight years, they did not generate traffic or noise problems.

“In the 16 years that our church has been in existence, we’ve had such an amazing positive impact in people’s lives,” Palompo said Saturday. “I just want to assure everyone that we are going to continue with our vision and mission to make peoples’ lives better and more blessed.”

New Hope Central Oahu hosts services Saturday nights and Sunday mornings at the Mililani Tech Park. Other nearby locations include campuses in Haleiwa and Wahiawa.

David Brotchie of Group 70 International, an architecture, planning and engineering firm, told members of the Mililani Mauka/Launani Valley Neighborhood Board in June that the project includes installing new water quality features that “would actually work better.” The plan would use vegetation and other features to clean stormwater, which would eventually discharge into a gully.

Brotchie said it would cost about $1 million to build the new filtration system.

Palompo added that the system “will be superior” to the current one, which he said does not meet federal standards.

A traffic engineer estimated that the church would have “a very noticeable effect on traffic volumes” at the site and that church events would mainly be held during non-rush-hour times. Peak traffic on Lehiwa Drive mainly occurs during the morning and afternoon.

Officials have recommended that due to the traffic generated during some major events, the church provide off-site parking and a shuttle service.

Board member Luella Costales supports the project.

For area residents affiliated with New Hope and other churches, “it was really about building the church and creating a sense of community for families, for youths, for a place to go,” Costales said at the June meeting. “I really feel for the residents who do have the traffic concerns and some of the drainage issues. But I think that was addressed.”

The project has garnered concerns from several community members, prompting a group of residents to start an online petition protesting the development. The petition, which had 110 supporters Friday, maintains that the new church “will severely block the stormwater runoff, raise the risk of flooding in Mililani Mauka, significantly increase the traffic flow in a quiet residential neighborhood and ruin our residential view plane.”

Board Vice Chairman Stanton Oishi expressed concerns at the June meeting about better communicating and notifying residents about the project.

“It’s a very big thing for the community,” Oishi said. “There’s a lot of positives. There’s a lot of concerns.”

A motion for the neighborhood board to send a letter of support to the planning department failed to be adopted at the June meeting.

Board Chairman Dean Hazama, who recused himself from the vote because he is a New Hope member, expressed some concerns about noise but added that the community could work with the church to mitigate that issue. Regarding traffic, Hazama, who lives a few blocks from the site, said the church would typically use the facility during non-rush-hour times.

He added that the church offers several outreach programs, including one that encourages youth community participation.

“The church has been in the mauka community for quite a while,” Hazama said Friday. “(But) I would have some concerns if the project is negatively impacting residents.”